HoloWiki - A Holography FAQ holowiki https://holographyforum.org/wiki/Main_Page MediaWiki 1.31.0 first-letter Media Special Talk User User talk HoloWiki - A Holography FAQ HoloWiki - A Holography FAQ talk File File talk MediaWiki MediaWiki talk Template Template talk Help Help talk Category Category talk Gadget Gadget talk Gadget definition Gadget definition talk 0 267 381 2006-02-16T16:36:38Z 68.127.162.37 0 wikitext text/x-wiki Make sure your edit is needed! Using double squar brackets around a word will make a new page with that name or link to an existing page. Using "===section Title===" Makes sections and a contents section on a page. Using single square brackets makes an external link to a web site. 9880fa78c631a72fb1167cb119d0071095cfdb6e 0 266 379 2006-02-18T00:45:06Z 68.127.155.163 0 wikitext text/x-wiki This is a resource created by a bunch of holographers. We try to keep it accurate but use your own judgment. If we say it is impossible then it might not work. If we say it is easy then it might be possible. :-) 1944d46b3604751ff1ea4f270be3c6f5b2d9c3fb 0 211 269 2006-02-18T21:09:42Z Colin Kaminski 0 wikitext text/x-wiki from [http://Nobelprize.org www.nobelprize.org] Dennis Gabor – Autobiography [[Image:Gabor.gif]] I was born in Budapest, Hungary, on June 5, 1900, the oldest son of Bertalan Gabor, director of a mining company, and his wife Adrienne. My life-long love of physics started suddenly at the age of 15. I could not wait until I got to the university, I learned the calculus and worked through the textbook of Chwolson, the largest at that time, in the next two years. I remember how fascinated I was by Abbe's theory of the microscope and by Gabriel Lippmann's method of colour photography, which played such a great part in my work, 30 years later. Also, with my late brother George, we built up a little laboratory in our home, where we could repeat most experiments which were modern at that time, such as wireless X-rays and radioactivity. Yet, when I reached university age, I opted for engineering instead of physics. Physics was not yet a profession in Hungary, with a total of half-a-dozen university chairs - and who could have been presumptious enough to aspire to one of these? So I acquired my degrees, (Diploma at the Technische Hochschule Berlin, 1924, Dr-Ing. in 1927), in electrical engineering, though I sneaked over from the TH as often as possible to the University of Berlin, were physics at that time was at its apogee, with Einstein, Planck, Nernst and v. Laue. Though electrical engineering remained my profession, my work was almost always in applied physics. My doctorate work was the development of one of the first high speed cathode ray oscillographs and in the course of this I made the first iron-shrouded magnetic electron lens. In 1927 I joined the Siemens & Halske AG where I made my first of my successful inventions; the high pressure quartz mercury lamp with superheated vapour and the molybdenum tape seal, since used in millions of streeet lamps. This was also my first exercise in serendipity, (the art of looking for something and finding something else), because I was not after a mercury lamp but after a cadmium lamp, and that was not a success. In 1933, when Hitler came to power, I left Germany and after a short period in Hungary went to England. At that time, in 1934, England was still in the depths of the depression, and jobs for foreigners were very difficult. I obtained employment with the British Thomson-Houston Co., Rugby, on an inventor's agreement. The invention was a gas discharge tube with a positive characteristic, which could be operated on the mains. Unfortunately, most of its light emission was in the short ultraviolet, so that it failed to give good efficiency with the available fluorescent powders, but at least it gave me a foothold in the BTH Research Laboratory, where I remained until the end of 1948. The years after the war were the most fruitful. I wrote, among many others, my first papers on communication theory, I developed a system of stereoscopic cinematography, and in the last year, 1948 I carried out the basic experiments in holography, at that time called "wavefront reconstruction". This again was an exercise in serendipity. The original objective was an improved electron microscope, capable of resolving atomic lattices and seeing single atoms. Three year's work, 1950-53, carried out in collaboration with the AEI Research Laboratory in Aldermaston, led to some respectable results, but still far from the goal. We had started 20 years too early. Only in recent years have certain auxiliary techniques developed to the point when electron holography could become a success. On the other hand, optical holography has become a world success after the invention and introduction of the laser, and acoustical holography has now also made a promising start. On January 1, 1949 I joined the Imperial College of Science & Technology in London, first as a Reader in Electronics, later as Professor of Applied Electron Physics, until my retirement in 1967. This was a happy time. With my young doctorands as collaborators I attacked many problems, almost always difficult ones. The first was the elucidation of Langmuirs Paradox, the inexplicably intense apparent electron interaction, in low pressure mercury arcs. The explanation was that the electrons exchanged energy not with one another, by collisions, but by interaction with an oscillating boundary layer at the wall of the discharge vessel. We made also a Wilson cloud chamber, in which the velocity of particles became measurable by impressing on them a high frequency, critical field, which produced time marks on the paths, at the points of maximum ionisation. Other developments were: a holographic microscope, a new electron-velocity spectroscope an analogue computer which was a universal, non-linear "learning" predictor, recognizer and simulator of time series, a flat thin colour television tube, and a new type of thermionic converter. Theoretical work included communication theory, plasma theory, magnetron theory and I spent several years on a scheme of fusion, in which a critical high temperature plasma would have been established by a 1000 ampere space charge-compensated ion beam, fast enough to run over the many unstable modes which arise during its formation. Fortunately the theory showed that at least one unstable mode always remained, so that no money had to be spent on its development. After my retirement in 1967 I remained connected with the Imperial College as a Senior Research Fellow and I became Staff Scientist of CBS Laboratories, Stamford, Conn. where I have collaborated with the President, my life-long friend, Dr. Peter C. Goldmark in many new schemes of communication and display. This kept me happily occupied as an inventor, but meanwhile, ever since 1958, I have spent much time on a new interest; the future of our industrial civilisation. I became more and more convinced that a serious mismatch has developed between technology and our social institutions, and that inventive minds ought to consider social inventions as their first priority. This conviction has found expression in three books, Inventing the Future, 1963, Innovations, 1970, and The Mature Society, 1972. Though I still have much unfinished technological work on my hands, I consider this as my first priority in my remaining years. Honours Fellow of the Royal Society, 1956. Hon. Member of the Hungarian Academy of Sciences, 1964. D.Sc. Univ. of London, 1964, Hon. D.Sc. Univ. of Southampton, 1970, and Technological University Delft, 1971. Thomas Young Medal of Physical Society London, 1967. Cristoforo Colombo Prize of Int. Inst. Communications, Genoa, 1967. Albert Michelson Medal of The Franklin Institute, Philadelphia, 1968. Rumford Medal of the Royal Society, 1968. Medal of Honor of the Institution of Electrical and Electronic Engineers,1970. Prix Holweck of the French Physical Society, 1971. Commander of the Order of the British Empire, 1970. Married since 1936 to Marjorie Louise, daughter of Joseph Kennard Butler and Louise Butler of Rugby. From Les Prix Nobel en 1971, Editor Wilhelm Odelberg, [Nobel Foundation], Stockholm, 1972 This autobiography/biography was written at the time of the award and later published in the book series Les Prix Nobel/Nobel Lectures. The information is sometimes updated with an addendum submitted by the Laureate. To cite this document, always state the source as shown above. Dennis Gabor died on February 8, 1979. da0bbce15e2113daaa6ef128352e50f0980f1522 6 147 565 147 2006-02-18T21:10:58Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 515 1180 2006-02-18T21:26:02Z Colin Kaminski 0 wikitext text/x-wiki Stephen Benton [[Image:Benton.jpg]] In Memory: (December 1, 1941 - November 9, 2003) Allen Professor of Media Arts and Sciences Director, Center for Advanced Visual Studies Group: Spatial Imaging [http://www.media.mit.edu/~sab Benton at MIT]] Biography Stephen Benton was best known as the inventor of the white-light "rainbow" hologram, most often seen on credit cards and magazine covers. He was also known for the work he and his group did to create the world's first real-time interactive holographic video system. He was a prolific author and held multiple patents in optical physics, photography, and holography. Benton headed the Lab's Spatial Imaging research group. While an MIT undergraduate, Benton worked with Harold "Doc" Edgerton in the famous "Strobe Lab," and received his BS degree in electrical engineering in 1963. He continued his studies at Harvard University, receiving a PhD in applied physics in 1968, and remained at Harvard until 1973 as its first assistant professor of applied optics. He was associated with laboratories of the late Edwin Land at Polaroid Corporation since his undergraduate days, and returned there to establish an imaging physics laboratory, where he did much of the early work on white-light viewable holograms, and explored other applications of lasers to photography. Curriculum Vita 1999 E. Rudge ('48) and Nancy Allen Professor of Media Arts & Sciences Head, Spatial Imaging Group, Media Laboratory Director, Center for Advanced Visual Studies (CAVS) Graduate Officer, Program in Media Arts & Sciences Massachusetts Institute of Technology 1999 Vice President, Society for Imaging Science & Technology 1996 Director, Center for Advanced Visual Studies (CAVS) 1990 - 1993 Board of Governors, Int'l Soc. Optical Eng'g (SPIE) 1987 - 1994 Founding Head, MIT Program in Media Arts & Sciences 1987 - 1992 Board of Trustees, Museum of Holography, New York 1984 Founding Faculty, Media Laboratory, MIT 1982 Founder, Spatial Imaging Group, MIT 1980 - 1984 Chairman, US National Committee for the International Commission for Optics 1980 - 1983 Visiting Scientist, MIT Laser Research Center 1979 - 1984 Visiting Committee, International Museum of Photography at George Eastman House 1978 - 1981 Board of Directors, Optical Society of America 1976 - 1977 President, Optical Society of America, New England Section 1973 - 1982 Senior Scientist, Polaroid Corporation 1968 - 1973 Assistant Professor of Applied Optics, Harvard University PUBLICATIONS: Articles: 46 Patents: 14 EDUCATION: Bachelor of Science in Electrical Engineering, MIT, 1963 Master of Science in Engineering, Harvard University, 1964 Doctor of Philosophy in Applied Physics, Harvard University, 1968 PROFESSIONAL SOCIETIES Optical Society of America (Fellow, former Director) Society for Imaging Science & Technology (IS&T/SPSE) (Fellow, Vice President) Institute of Electrical & Electronic Engineers The International Society for Optical Engineering (SPIE) (Fellow, former Director) Society for Information Display (SID) Holographic Display Engineers & Artists Club (HODIC, Japan) 42cb8fb62edab870ef208aab91ebf66a925f988a 6 110 451 110 2006-02-18T21:27:00Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 85 793 85 2006-02-18T21:32:45Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 455 1060 2006-02-18T21:33:43Z Colin Kaminski 0 wikitext text/x-wiki [[Image:Pchristie.jpg]] [http://www.litiholographics.com Liti Holographics] Company founder, President and Chief Technology Officer Mr. Christie has extensive knowledge and experience in developing optical systems. Prior to completing graduate work in holographic & three-dimensional display technology at MIT, one of the world’s leading media labs, Mr. Christie was responsible for inventing several new technologies for improving LCD projection displays for Projectavision, Inc., one of which was patented. His Masters Degree work is also currently being patented by MIT. He subsequently formed the predecessor company to Liti Holographics in December of 1997. He holds a Bachelor's degree in Applied Physics from Columbia University and a Master's degree in Media Technology from MIT. 5a55966785e353be7412e05b6f4cac2af30114d6 6 121 495 121 2006-02-18T21:38:00Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 118 481 118 2006-02-18T23:09:54Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 248 343 2006-02-18T23:42:48Z Colin Kaminski 0 wikitext text/x-wiki [http://www.hmt.com/holography/cherry/cherry.html Web Site] 7c5e221c386a92d9cfa6c7f0ab4dd7f17afe3556 6 60 733 60 2006-02-19T03:35:49Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 597 1344 2006-02-19T03:56:37Z Colin Kaminski 0 wikitext text/x-wiki [http://www.ultimate-holography.com/ Ultimate] f53c72dd5cf18f75124dee086093de3f6f579631 0 457 1064 2006-02-19T03:58:18Z Colin Kaminski 0 wikitext text/x-wiki [http://www.pearljohn.co.uk/holography.html Pearl John] b2b34e9bdb5d899ee8a717fcc8499bb6e2e76a03 6 137 529 137 2006-02-19T21:58:28Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 140 543 140 2006-02-20T06:31:20Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 79 775 79 2006-02-21T15:45:35Z Michael Harrison 0 Dag photo of Michael Harrison taken in Spain 2005 wikitext text/x-wiki Dag photo of Michael Harrison taken in Spain 2005 fa657036337a16da2ec2ddf7dde9c9255fc4de95 0 433 1016 2006-02-21T16:08:59Z Colin Kaminski 0 wikitext text/x-wiki [[Image:Mmueller.jpg]] Martin Mueller Born and lives in Zurich, Switzerland. Used to work as a freelance journalist, essay writer and translator. Caught the holography virus (1980) when writing an essay on holography (which put emphasis on forerunners in the arts mainly). Run a small holography business with Ralph Kuehne for more than ten years. 1998 begin of friendship and cooperation with Sergio Oliveira (Sao Paulo, Brazil), which led to the development of a new photopolymer system [http://www.polygrama.co.nr/ Polygrama]. cfd3ff4e3ecac1d5d56db9280a1b575f0b50d346 6 81 779 81 2006-02-21T16:13:54Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 398 947 2006-02-21T23:47:18Z Colin Kaminski 0 wikitext text/x-wiki [[Image:Jross.jpg]] JONATHAN ROSS [http://www.jrholocollection.com WebSite] CURRICULUM VITAE BORN 1953 London EDUCATED Bryanston School, Dorset 1970 - 71 Studied Art History in Venice and London 1972 - 77 Worked as assistant in Film Production and Theatre Management 1978 - 79 Founded and managed The Hologram Place - The first European gallery devoted to holography 1978 - 90 Founded and managed SEE 3 (HOLOGRAMS) LTD. - a production company for the manufacture of display holograms 1992 Organised “Four British Holographers” exhibition at Smith’s Gallery Covent Garden 1993 Organised “Landscapes & Metamorphoses” exhibition at Smith’s Gallery 1994 Organised “3x8+1” a selection of holograms from personal collection at Milton Gallery, St.Paul’s School, London 1995 Contributed selection of holograms to “Holograms from around the World” James Dun’s House (Aberdeen Art Gallery) Guest curator of “The Art of Holography” at the National Museum of Photography, Film & Television, Bradford 1996 Co-curator of “Raum in Sicht - Magie in 3-D”, Technorama Switzerland. Special Consultant to Art in Holography2 Symposium, Nottingham University Exhibited selection from collection and gave paper on collecting holograms. 1997 Exhibited selection from collection at The Royal Photographic Society, Bath. 1998 Founded Gallery 286 in Earl’s Court Road, London and has curated an ongoing programme of exhibitions featuring holographers, photographers, painters and sculptors. Over 50 exhibitions to date, including one-person shows by John Kaufman, Andrew Pepper, Margaret Benyon, Matthew Schreiber, Jon Mitton and Pearl John 1999 Advisor to the Shearwater Foundation Holography Award Programme 2000 A special Exhibition of work selected from the collection at The Butler Institute of American Art, Youngstown, Ohio, USA The Royal Photographic Society Holography Group Summer Exhibition 2000. A selection of work from the Jonathan Ross Collection. 2004 Received The Royal Photographic Society Saxby Medal for contributions to 3-D Image-making 1988 - 93 Consultant Editor, Art Line International Art News 1983 - Hon.Treasurer, Royal Photographic Society Holography Group During his long association with holography, Jonathan Ross has assembled one of the world's most extensive collections of holograms, details of which can be found at http://www.jrholocollection.com c493b47d5163d6f4898344f036ba3f16f3772b6b 6 40 677 40 2006-02-21T23:47:40Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 158 163 2006-02-22T01:30:28Z Colin Kaminski 0 A Beginners Guide to DCG moved to A Beginners Approach to DCG wikitext text/x-wiki #redirect [[A Beginners Approach to DCG]] 00326dff2d8e6c55534a1327009e21165d697841 6 78 773 78 2006-02-22T01:42:24Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 157 161 2006-02-24T13:30:35Z John Pecora 0 wikitext text/x-wiki '''A Beginners Approach to DCG Holography''' By: [[John Pecora]] (Note: as this is an original article please do not edit it unless you are John. Please use the discussion page to comment on this work.) ==Abstract== As the availability of green lasers becomes cheaper and more widespread, so does the potential for one to make their own Dichromated Gelatin (DCG) film and holograms. The purpose of this paper is to provide a basic step-by-step set of procedures such that the beginner may have success in producing their own DCG film and making simple DCG Holograms. There are many variables in the fabrication and processing which alter the aesthetics of a DCG hologram, most of which will be beyond the scope of this paper. And the basics here will not guarantee a professional quality hologram but will lead the reader down one correct path to successfully make DCG film and DCG holograms. It will be up the reader to take the next steps to perfect the quality and repeatability of the DCG hologram process. ==Introduction== DCG emulsion is made from a simple solution of Ammonium (or Potassium) Dichromate, Raw Gelatin and Water. Exposure to the DCG emulsion is done in the Green or Blue with higher sensitivity to the shorter wavelengths. Processing is simply a soak in Standard Photographic Fixer followed by a soak in water followed by a dehydrating process in one or more alcohol concentration baths. As a DCG hologram is susceptible to image loss when exposed to moisture, the DCG hologram will be sealed. There is a multitude of ways to perform each of these functions and the ones presented here have been tried and prove to work but may not be the best or suit a particular application for the DCG hologram. ALSO, IT IS VERY IMPORTANT TO INSURE SAFETY AT EACH STEP OF THE PROCESS USING GOOD CHEMICAL SAFETY PRACTICES, KNOWLEDGE OF THE CHEMICALS AND EQUIPMENT BEING USED, PROPER DISPOSAL OF CHEMICALS AND COMMON SENSE. It is not within the scope of this paper to point out safety hazards and it is the responsibility of the reader to research each and every potential safety hazard. I also suggest reading the entire paper first to familiarize your self with the procedures and note any materials and supplies you may need. ==Glass Preparation== Cleaning the glass properly is important. If the glass is not cleaned properly the emulsion can lift off the glass in spots or completely during processing. Also, if there are any dust particles, the emulsion tends to have different properties at that area and a circular ring of deformation of the hologram will be seen around that area. Soak the glass in a 3% concentration of Hydrochloric Acid overnight. This can be bought as Muriatic Acid from most home improvement centers. You could also use a 25% concentration of household bleach. This procedure also works for recycling glass from previously coated plates but I found the bleach takes longer. After soaking, using rubber gloves, scrub the plates with a plastic wool scrubby used for cleaning Teflon pans. Steel wool may scratch the glass. After scrubbing rinse the glass thoroughly under running water and place in a tray of running water. Then repeat the rinse process while rubbing again with the plastic wool. After the final rinse, lean the plates against the wall on a paper towel. Before the plates dry completely use a paper towel to dry off one plate at a time and continue to turn the paper towel until the plate is dry. You will hear and feel the difference between a damp plate and a dry one. Repeat for the other side of glass. Do not touch the plate with your skin or oils will be left behind which can also cause the emulsion not to stick to the glass. ==DCG Emulsion Fabrication== DCG emulsion is comprised of an amount of Distilled Water, Dry Gelatin and Ammonium (or Potassium) Dichromate. A good starting formula is 100:12:3 for the procedures described here. Take the water and place it in a heat resistant glass or plastic container. Place this on a Magnetic Heater/Stirrer or in a double boiler. Add the Gelatin to the water while it is cool and allow it to mix for a couple of minutes. If you are not using a Heater/stirrer the stirring should be done by hand. Bring the temperature up slowly to a maximum of 120 F and a minimum of 110F. Once the solution reaches the 110 F temperature continue mixing until the gelatin mixture is completely dissolved. With the Heater/stirrer allow the solution to be well mixed the entire time but not so fast as to cause excessive bubbles or foam. By hand, mix well for one minute every 5 minutes (this get laborious by hand). Mixing too long is better then under mixing and I suggest 45 minutes after the minimum temperature is reached for a more aesthetic hologram. But again shorter times may be used as long as the gelatin is dissolved. It will look very clear and not cloudy when dissolved with no suspended particles. FROM THIS POINT ON A SAFELIGHT MUST BE USED UNTIL AFTER THE WATER BATH IN PROCESSING. A good safelight to use is a standard yellow incandescent bug light. Now add the Dichromate. Allow this to mix until it is all dissolved (about 15 minutes) within the same temperature range. When this is completed, filter the mixture through a paper coffee filter into a clean container. A funnel or similar can be used to hold the coffee filter paper. It is best to allow the narrow end of the funnel to touch or be very close to the bottom of the final pouring container such that dripping from the funnel end does not produce bubbles. The container can be a beaker or other similar container that can easily be poured from but at the same time can be put back on the Heater/stirrer or back in the double boiler to maintain the previous temperature range. If the emulsion is cooler during coating the final emulsion thickness will be thicker. Take a Q-tip and pop or remove any small bubbles that may be on the emulsion. The emulsion is now ready to coat. The emulsion can be stored at this time in a refrigerator but should be sealed, labeled and not allowed to be exposed to light. ==Plate Coating== The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70F.) Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45 degree angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. Take the plate and immediately place it on a table and spin it as 78 RPM’s. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. I prefer the spin method. If you run out of emulsion in the pouring container, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. ==Exposing the Plate== The plate is best after 4 hours old and can be up to a week(s) old. I have found the brightest holograms are between the 4 and 12 hour age. It seems when plates are older they are harder to get broadband replay and/or replay into shorter wavelengths and lose some sensitivity. The simplest recoding geometry is a Single Beam Reflection in which the object is lying down on its back and the plate is laid right on top of the object. Make sure the object and plate do not wobble. Place the emulsion facing the object. As DCG is quite relaxing in the energy requirements I suggest doing test exposures with the times being doubled thus covering the largest range of times in the least amount or test exposures. Once the time range is found with your laser it will be easy to reproduce. An example is 10 seconds, 20 seconds, 40 seconds, 80 seconds, and 160 seconds. After exposure allow the plate to set in complete darkness for 2 to 5 minutes before processing. ==Processing the Plate== All temperatures can be at room temperature (70F). Take the plate and put it in Kodak Rapid Fixer with hardener. The Fixer should be mixed as per the instructions for the most dilute mixture (paper 1:7). Gently rock the tray until all yellow is gone then an additional 15 seconds. This should take anywhere from ½ minute to 2 minutes. I use a white tray to observe the yellow more easily. Once this is completed, place the plate in running water for 5 minutes ( a tray of water can be used if running water is not available). I now turn on a quartz halogen light that shines on the spot where I will lean the hologram to blow it dry. Then take the plate and place it in 35% alcohol for 15 seconds. Then 70% alcohol for 15 seconds, then 91% alcohol for 15 seconds then finally 100% alcohol until diffraction is visible (anywhere from 15 seconds to two minutes or longer). As soon as diffraction (colors) is seen allow another 15 seconds in that bath. Then take the plate out and lean it against the wall in the overhead light. With practice you will find which angle the diffraction is seen in the light and which way that relates to the visibility of the hologram when blow drying it. As soon as you lean the plate against the wall begin blow drying it with a hair dryer set on its hottest and strongest settings. Blow dry very close to the plate. Start at the center and in a circular motion move to the outside of the plate and repeat often. If the plate is leaning the right way the diffraction and image should start to get really bright. Continue drying until hologram in completely dry. You cannot over dry but you can under dry. This usually takes me 5 minutes minimum. ==Sealing the Hologram== If the hologram is acceptable in quality and brightness to your liking, it must be sealed against moisture. After it is completely dry, use a razor to scrap off ¼ inch of emulsion from around all 4 edges. Three edges will be easy if you maintained ¼ inch when pouring the coating. The bottom wiped edge from coating will probably need the most attention. Now have another cleaned piece of glass ready the same size as the hologram. Mix up some 5 minute 2-part epoxy. I use a Q-Tip with the swab cut off. Now take the Q-Tip and use it to lay down a bead of epoxy around the entire cleaned edge on the emulsion side of the hologram. Take the clear cleaned piece of glass and place it over the hologram. You should see the epoxy sandwiched between the glass plates at the edge where the emulsion was scraped. Look closely and make sure there are not voids where the epoxy did not get sandwiched. Let the plates dry horizontally and check often to make sure the top plate does not slide and move into a different location. After about 15 minutes the hologram can be displayed as liked. d3777ac456286777b128f7da3cf645424ae416dd 0 198 243 2006-02-25T06:58:28Z Colin Kaminski 0 Copywrite moved to Copyright wikitext text/x-wiki Unless otherwise stated by the author the copyright for the HoloWiki will be GNU Public Documentation License as follows: Copyright (C) 2000,2001,2002 Free Software Foundation, Inc. 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. 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A copy of the license is included in the section entitled "GNU Free Documentation License". If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the "with...Texts." line with this: with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software. 67b097f4a3b57a00f7c1021260021f54e13518b1 6 108 445 108 2006-02-25T22:20:45Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 593 1336 2006-02-25T23:20:23Z Colin Kaminski 0 wikitext text/x-wiki A Wiki is really a large scratch pad that is edited by a collective. Wikis can be completely public or completely private. The HoloWiki can be viewed by all but only edited by registered users. At any time any page on a Wiki can be edited by any user. The software logs all edits and an editor can look back to older revisions in order to save deleted information or have it for reference during an edit. The word Wiki is from the Hawiian language where wiki wiki means quickly. Feel free to edit any page that is not an author specific article. Any author specific articles should have comments put into the discussion link at the top of the page. This will allow the author to make the edits. This is a professional courtesy to our authors that have spent considerable time writing an article. Also, I intend to have the biographies be a place where a holographer represents themselves. Please do not use them to review their work. If we need a place to review work we can make a new section. d777603bcdfd280e28d122be22972a66c71dbd8b 0 268 383 2006-02-25T23:26:19Z Colin Kaminski 0 wikitext text/x-wiki Any user who defaces the HoloWiki or demeans another person will be blocked. 66e91aab2263210847e22770e1b481b35b6c4657 0 224 295 2006-02-26T03:11:35Z Colin Kaminski 0 wikitext text/x-wiki Emmett Leith (born in Detroit, Michigan, died December 23, 2005) was a professor of electrical engineering at the University of Michigan and the inventor of three-dimensional holography. Leith was educated at Wayne State University. Professor Leith and his coworker Juris Upatnieks displayed the world's first three-dimensional hologram at a conference of the Optical Society of America in 1964. In 1979, President Jimmy Carter awarded Leith with the National Medal of Science for his research. [http://en.wikipedia.org/wiki/Emmett_Leith Wikipedia] b09d470ab056dffbfb13e4eebf9958fb02e01398 1 547 1244 2006-02-27T14:58:56Z John Pecora 0 wikitext text/x-wiki This isn't really DCG specific is it? Well, I guess maybe it could be modified for gelatin only but I seem to realise that the Silver method that uses gelatin is at a much higher concentration and thus thicker and may prove to be diferent. I figured to keep it as knowledgable and first hand as possible I would post it as DCG and others could add another section for plain gelatin. What do you think? JohnFP. d064b8e7136b44c4fa5491ad47a4a0ce0844ce9b 0 215 277 2006-02-27T15:37:17Z Michael Harrison 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 399 949 2006-02-27T15:37:45Z Michael Harrison 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 525 1200 2006-02-27T18:02:13Z Colin Kaminski 0 wikitext text/x-wiki Hope you don't mind, I made some changes. JohnFP Nice Work! Colin 876fd9380f0544d2b80de25577d7bd9c7e96167e 1 527 1204 2006-02-27T20:46:37Z John Pecora 0 wikitext text/x-wiki If anyone has used gelatin to fabricate a Silver Halide Emulsion, please include in this article the bloom and Type gelatin used if it was sucessful. JohnFP. feafd7de078bebeb4f1bfad90517cb4b17c23b1c 0 397 945 2006-03-01T14:10:22Z John Pecora 0 wikitext text/x-wiki Sorry, I had more of a holography history for me then a biography. I have an AA degree from a local Community College with an emphasis in Computer Science. I furthered my education at University of Maryland with Physics, Math and Computer Classes. I am a Microsoft Certified Systems Engineer and presently design Wide Area Networks. I have worked at North East Holographics and responsibilities included: Design, configure and produce H1 multi-channel rainbow master holograms for replay with a HeCd laser using a large frame Argon Ion laser. Design, configure and produce H2 rainbow copy holograms in Photoresist utilizing a fringe locker to help with stability during the long exposure times and using a HeCd laser. Fabricate Photoresist emulsions on glass plates. Implemented quality control of Photoresist plates. Silverized the Photoresist plates with an atomizing spray system. Built, maintained and controlled variables for producing different types of Nickel Shims made from the Silverized Photoresist plates. Built, maintained and operated a complete wide format Embossing Printer used to hot stamp nickel shim hologram in foil backed plastics. I have also been involved with amateur holography since 1982 working with Silver Halide. Currently and for the past 3 years I have been concentrating my efforts in working with Fabrication and production of Dichromated Gelatin holograms implementing a variety of techniques formulas and geometries. I have moved from the basement to a dedicated lab. f03f3c53cb3b477bcc67f54174be4a09264d507c 0 424 998 2006-03-02T02:40:44Z Colin Kaminski 0 wikitext text/x-wiki [[Image:Lcross.jpg]] ad8cf59eb04fa1975b0157f132d7cf769aa2afcf 6 59 731 59 2006-03-02T02:41:39Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 415 980 2006-03-02T16:10:43Z Colin Kaminski 0 wikitext text/x-wiki ==What is Light?== ==Learning About the Spectrum== ==Is Light a Wave?== Young's Double Slit Experiment. ==Learning About Interference== ==How Does a Laser Work?== bc482e8c7ea2e1eeb82418ada7148194add195da 6 33 661 33 2006-03-04T21:26:22Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 7 863 7 2006-03-04T21:31:35Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 12 869 12 2006-03-04T21:42:09Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 96 423 96 2006-03-04T21:54:07Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 123 499 123 2006-03-04T22:21:11Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 82 781 82 2006-03-05T21:38:04Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 45 695 45 2006-03-06T00:03:47Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 127 509 127 2006-03-06T02:40:16Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 128 511 128 2006-03-06T03:29:22Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 129 513 129 2006-03-06T03:37:17Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 130 515 130 2006-03-07T06:50:20Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 131 517 131 2006-03-07T06:55:57Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 132 519 132 2006-03-07T07:03:39Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 133 521 133 2006-03-07T07:04:35Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 134 523 134 2006-03-07T07:05:33Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 135 525 135 2006-03-07T14:58:31Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 136 527 136 2006-03-07T14:59:13Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 124 503 124 2006-03-07T14:59:59Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 125 505 125 2006-03-07T15:00:49Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 126 507 126 2006-03-07T15:01:37Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 532 1214 2006-03-07T23:48:26Z Colin Kaminski 0 wikitext text/x-wiki I am not sure where to put this but one of the things that I think always presents confusion for beginning holographers is which way to orient the geometry of and H1 (overhead lighting, below lighting etc.) so that the final H2 hologram has overhead lighting with the virtual view. Where would this best be placed and what should it be called? JohnFP. ---- Put that into Holopraphy Technology:H1 to H2 Copies. I messed that one up at PCG I. 8) I will eventually get to diagram all of the set ups for that section in my CAD program. - Colin ---- This page has turned into a nice Beginner FAQ. I wonder if the page title should be adjusted to match? - Phil Edit: Oops, I see the main page already calls it a FAQ. That's probably fine. ---- I think we shold rename it to have FAQ in the title. It will help with search engines. 08a3381cef605b5140ae5dae5ceee30a9b95a2a3 6 152 593 152 2006-03-08T00:15:06Z Phil Edelbrock 0 test image wikitext text/x-wiki test image 203fee975fbd208c63d07f5c5ec42dbce4c21d84 6 2 827 2 2006-03-08T19:08:56Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 3 829 3 2006-03-08T19:11:06Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 508 1166 2006-03-08T19:13:46Z John Pecora 0 wikitext text/x-wiki [[Image:SBR.JPG]] Side View The expanded laser beam, diverging, is coming in from above left. You can see with only an approximate 50 degree reference angle, the plate needs to be considerably larger then the object such that the top of the plate does not bisect the object (object shadow is very near top of plate shadow) or one could choose a shallower object. With the addition of black tape across the top of the plate (not shown here) to elliminate internal reflections, the top edge of the plate shadow whould be thicker and darker. [[Image:SBR2.JPG]] Front View The expanded laser beam, diverging, is coming in from above and just to right of camera view. 8fd7b89a7a13b7fde5e663319adb824e977e0464 6 46 699 46 2006-03-09T03:11:15Z Phil Edelbrock 0 A light bulb lit up the hard way. wikitext text/x-wiki A light bulb lit up the hard way. d1eca86d96570b64cb9e10026fa68d1e55099718 0 474 1098 2006-03-09T16:01:24Z Colin Kaminski 0 wikitext text/x-wiki This page is under construction! Here is an example MSDS for denatured alcohol. MSDS 03200, Revision 2.0 / Revision Date 12/18/01 JC Formula 3 200 Proof / Page 1 of 2 Product Information (xxx) xxx-xxxx / Emergency Assistance (xxx) xxx-xxxx MATERIAL SAFETY DATA SHEETS SECTION I PRODUCT AND COMPANY IDENTIFICATION PRODUCT: Denatured Ethanol, Anhydrous (Prop Solv. #3) This MSDS is valid for all grades and catalog #’s including 123PS3200 and 124003200 Synonyms: Denatured Ethanol Anhydrous, Industrial Alcohol Formula: Mixture Manufacturer: Pharmco Products Inc. 58 Vale Road Brookfield, Connecticut 06804, USA Phone (203) 740-3471 Fax (203) 740-3481 Emergency Contact: CHEMTREC 1-800-424-9300 SECTION II COMPOSITION /INFORMATION ON INGREDIENTS %vol Material CAS Exposure Limits 92.46 Ethanol 64-17-5 1000ppm TWA 3.7 Methanol 67-56-1 200ppm TWA, OSHA/ACGIH;250pp m STEL OSHA/ACGIH 1.9 MIBK 108-10-1 50ppm PEL/OSHA; 50ppm TLV .97 Ethyl Acetate 141-78-6 400ppm TWA .97 Toluene 108-88-3 100ppm TWA/OSHA 150ppm STEL/OSHA SECTION III HAZARDS IDENTIFICATION Carcinogen Status: Established uses of denatured ethanol are not considered to pose a significant cancer hazard. Poisonous: This product contains methanol. It can not be made non-poisonous. Ingestion of 60-200ml of methanol is a fatal dose for most adults. Ingestion of 10ml may cause blindness. Routes of Exposure: Swallowing: May cause dizziness, faintness, drowsiness decreased awareness or responsiveness, nausea, vomiting, staggering gait, lack of coordination, blindness, coma and death. Skin Absorption: Prolonged or widespread contact may result in the absorption of potentially harmful amounts. Inhalation: High vapor concentration may cause burning sensation in nose and throat and stinging and watering in the eyes. At concentrations which cause irritation, dizziness, faintness, drowsiness, nausea and vomiting may also occur. Skin Contact: Prolonged or repeated contact may cause defatting and drying of the skin. Eye Contact: May cause irritation including stinging, tearing, and redness Effects of Repeated Overexposure: Long term repeated oral exposure to ethanol may result in the development of progressive liver injury with fibrosis. Overexposure to methanol may cause eye damage and liver or kidney injury. Other Health Hazards: Repeated ingestion of ethanol by pregnant mothers has been shown to adversely affect the central nervous system of the fetus, producing a collection of effects which together constitute fetal alcohol syndrome. Medical Conditions Aggravated by Overexposure: Repeated exposure to ethanol may aggravate liver injury produced from other causes. Skin contact may aggravate dermatitis. SECTION IV FIRST AID Obtain medical attention for all cases of over-exposure. Swallowing: If patient is fully conscious, give two glasses of water. Induce vomiting. Obtain medical attention. Skin: Wash skin with soap and water for at least 15 minutes Inhalation: Remove to fresh air; Give artificial respiration if not breathing; If breathing is difficult oxygen may be given by qualified personnel; Obtain medical assistance is discomfort persists. Eye Contact: Flush eyes with water for at least 15 minutes. Obtain medical assistance. Note to Physician: Symptoms vary with alcohol level of the blood. Mild alcohol intoxication occurs at blood levels between 0.5-.15%. Approximately 25% of individuals show signs of intoxication at these levels. Above .15% the person is definitely under the influence of ethanol; 50-95% of individuals are clinically intoxicated at these levels. Severe poisoning occurs when the blood is ethanol level is 0.3- 0.5%. Above 0.5% the individual will be comatose and death can occur. The unabsorbed ethanol should be removed by gastric lavage after intubating the patient to prevent aspiration. Avoid the use of depressant drugs or the excessive administration of fluids. SECTION V FIRE FIGHTING MEASURES Fire/Explosive Properties - For Pure 200 Proof Ethanol Flash Point: 58F (14C)Tag Closed Cup Flammable Limits in Air (for ethanol): For pure ethanol: 3.3% - 19.0% Flammability Classification: 3 (NFPA) 1993 Emergency Response Guidebook: Guide 26 (for pure ethanol) 1996 North American Emergency Response Guidebook: Guide 127 (for pure ethanol) Extinguishing Media: Apply alcohol-type or all-purpose foam by manufacturer’s recommended techniques for large fires. Use carbon dioxide or dry chemical media for small fires. Special Fire Fighting Procedures: Use water spray to cool fireexposed containers and structures; Use water spray to disperse vapors - re-ignition is possible; Use self-contained breathing apparatus and protective clothing. Unusual Fire and Explosion Hazards: ¨ Vapors may travel to source of ignition and flash back. ¨ Vapors may settle in low or confined spaces. MSDS 03200, Revision 2.0 / Revision Date 12/18/01 JC Formula 3 200 Proof / Page 2 of 2 ¨ May produce a floating fire hazard. ¨ Static ignition hazard can result from handling and use. SECTION VI SPILL/ACCIDENTAL RELEASE MEASURES Small spills can be flushed with large amounts of water. Large spills: Eliminate all ignition sources; ground all equipment; do not walk through spill; stop spill if possible; prevent entry into sewers, confined spaces, etc.; use a vapor suppressing foam to reduce vapors; absorb spill with noncombustible matter and transfer to containers; use nonsparking tools to collect absorbed material. Refer to Section 11 for disposal information. SECTION VII HANDLING AND STORAGE ¨ Flammable material - keep away from heat, sparks, and flame; sudden releases of hot organic vapors or mists from process equipment operating at elevated temperature may result in ignitions without the presence of obvious ignition sources. ¨ Avoid contact with eyes. ¨ Keep container closed. ¨ Use with adequate ventilation. ¨ Ground container when transferring product. ¨ Vapors may collect in containers; treat empty containers as hazardous. ¨ Wash thoroughly after handling ¨ Vapors may settle in low or confined areas ¨ Danger - may cause blindness or death if swallowed SECTION VIII EXPOSURE CONTROLS / PERSONAL PROTECTION Ventilation: Special, local ventilation is needed where vapors escape to the workplace air Respiratory Protection: Use self-contained breathing apparatus in high vapor concentration Personal Protective Equipment: gloves, lab coat or uniform, safety glasses, eye wash, safety shower SECTION IX PHYSICAL AND CHEMICAL PROPERTIES Appearance: clear, colorless liquid Odor: characteristic Characteristics for 200 Proof Ethanol: Vapor pressure @ 20C: 44.6mm Hg Vapor density: 1.6 (air =1) Boiling point @ 760mm Hg: 78.3 C (172.9F) Freezing Point: < -114.1C (<-173.4F) Solubility in Water: 100% @ 20C Density @ 15.56C (60F) 6.6lbs/gal Evaporation Rate: 3.0 (butyl acetate = 1) Percent Volatiles: 100% Specific Gravity : .796 @ 15.56 SECTION X STABILITY/REACTIVITY INFORMATION Stability: Stable Conditions to avoid: None known Incompatibility/Materials to avoid: strong oxidizing agents; strong inorganic acids Hazardous Combustion/Decomposition Products: Carbon monoxide and/or carbon dioxide Hazardous Polymerization: Will not occur SECTION XI DISPOSAL CONSIDERATIONS Vapors may collect in empty containers. Treat empty containers as hazardous. Dispose of spill-clean up and other wastes in accordance with Federal, State, and local regulations. SECTION XII TRANSPORTATION INFORMATION Proper Shipping Name: Alcohol, nos Hazard Class: 3 UN Number: 1987 IMO Information: Alcohols, NOS Label of Class: 3 Packing Group II Intermediate flashpoint group SECTION XIII REGULATORY INFORMATION Federal EPA Comprehensive Environmental Response Compensation, and Liability Act of 1980 (CERCLA) requires notification of the National Response Center of release quantities of Hazardous Substances equal to or greater than the reportable quantities (RQs) in CFR. Components present in this product at a level which could require reporting under this statute are: Chemical CAS Number Upper Bound Conc. % MIBK 108-10-1 1.9 Methanol 67-56-1 3.7 Acetaldehyde 75-07-0 .0010 Toluene Ethyl Acetate 108-88-3 141-78-6 .97 .97 Superfund Amendments and Reauthorization Act of 1986 (SARA) Title III requires emergency planning based on threshold planning quantities and release reporting based on reportable quantities in 40 CFR 355 (used for SARA 302, 304, 311, and 312). Components present in this product at a level which could require reporting under this statute are: none. Superfund Amendments and Reauthorization Act of 1986 (SARA) Title III requires submission of annual reports of release of toxic chemicals that appear in 40 CFR 372 (for SARA 313). This information must be included in all MSDS’s that are copied and distributed for this material. Components present in this product at a level which could require reporting under the statute are: Methanol (67-56-1) upper bound concentration 3.7% Toxic Substances Control Act (TSCA) Status: The ingredients of this product are on the TSCA inventory. State Right to Know California Proposition 65: This product contains trace levels of acetaldehyde known to the State of California to cause cancer. This product contains toluene which the State of California has found to cause birth defects or other reproductive harm. Massachusetts: Hazardous substances and extraordinarily hazardous substances must be identified. Components present which could require reporting: Extraordinarily Hazardous (=> 0.0001%): Acetaldehyde (CAS 75-07-0) upper bound conc. .0010% Hazardous (=>1%): Ethanol (CAS 64-17-5) upper bound conc. 92.46% Methanol (CAS 67-56-1) upper bound conc. 3.7% Pennsylvania: Hazardous substances must be identified. Hazardous (=>1%): Ethanol (CAS 64-17-5) upper bound conc. 92.46% Methanol (CAS 67-56-1) upper bound conc. 3.7% California SCAQMD Rule 443.1 (VOC’s) A Volatile Organic Compound (VOC) is any volatile compound of carbon excluding methane, carbon monoxide, carbonic acid, metallic carbides, or carbonates, ammonium carbonate, 1,1,1 tri-chloroethane, methylene chloride, (FC-23), (CFC-113), (CFC-12), (CFC-11), (CFC-22), (CFC- 114) and (CFC-115). VOC 800g/l; vapor pressure 41.4 mm Hg @20C for pure 190 proof ethanol The information contained herein is based on data considered to be accurate. However, no warranty is expressed regarding the accuracy of these data or the results to be obtained from the use thereof. It is the user’s obligation to determine the conditions of safe use of the product. 9bc13a994de122c6c8cc31ced1cbda71f05e5a47 6 4 831 4 2006-03-10T00:19:07Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 5 833 5 2006-03-10T00:20:24Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 509 1168 2006-03-10T00:24:14Z John Pecora 0 wikitext text/x-wiki [[Image:SBT.JPG]] Side View The expanded laser beam, diverging, is coming in from above left. You can see that the object needs to be far enough away so that there is adequate lighting that can be seen by the plate but this does waste light. [[Image:SBT2.JPG]] Front View The expanded laser beam, diverging, is coming in from above and just to right of camera view. A simple mirror in the set up to gather some of the wasted light and redirect it to the object would be beneficial. d3422bfe838280c3d33dcc2b97da0debb725daab 6 47 707 47 2006-03-10T00:36:46Z Phil Edelbrock 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 541 1232 2006-03-10T03:02:30Z Colin Kaminski 0 wikitext text/x-wiki I like the beginning you have. The blue writing for the links is a little difficult however. Nice Image. a259d7830c1cad37e34dffd5976d58103c37ff43 6 48 709 48 2006-03-10T15:24:44Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 49 711 49 2006-03-10T16:08:36Z Colin Kaminski 0 More contrast and less brightness. wikitext text/x-wiki More contrast and less brightness. bb77f4ed57c622aa4a7a0851ca155bf49f44a879 6 97 425 97 2006-03-11T18:21:03Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 6 861 6 2006-03-11T18:51:05Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 98 427 98 2006-03-11T19:06:36Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 99 429 99 2006-03-11T19:15:37Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 100 431 100 2006-03-11T19:24:03Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 101 433 101 2006-03-11T19:43:17Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 102 435 102 2006-03-11T19:43:54Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 103 437 103 2006-03-11T19:48:43Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 104 439 104 2006-03-11T19:51:01Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 105 441 105 2006-03-11T20:55:41Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 57 727 57 2006-03-11T21:26:40Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 75 765 75 2006-03-11T21:27:29Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 58 729 58 2006-03-11T21:28:53Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 17 909 17 2006-03-11T21:40:00Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 43 687 43 2006-03-11T21:54:25Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 25 631 25 2006-03-11T22:56:10Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 153 645 153 2006-03-11T23:24:15Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 154 629 154 2006-03-11T23:25:01Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 26 633 26 2006-03-11T23:40:43Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 27 635 27 2006-03-11T23:41:23Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 28 637 28 2006-03-11T23:42:08Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 29 639 29 2006-03-11T23:43:17Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 30 641 30 2006-03-11T23:44:06Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 31 643 31 2006-03-11T23:45:34Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 141 545 141 2006-03-12T00:47:48Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 144 551 144 2006-03-12T00:49:00Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 143 549 143 2006-03-12T00:51:05Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 145 553 145 2006-03-12T00:52:40Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 146 555 146 2006-03-12T00:53:50Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 142 547 142 2006-03-12T00:54:44Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 241 329 2006-03-12T01:53:45Z Colin Kaminski 0 wikitext text/x-wiki From "Electron Micrographs of Hologram Cross-sections" Motoo Akagi, Tadao Kaneko, Tsutomu Ishiba. Applied Physics Letters, Vol 21, No. 3, 1 August 1972. The photos below were made with [http://en.wikipedia.org/wiki/Transmission_electron_microscope| Transmission Electron Microscopy]. [[Image:Fringes1.jpg]] 20u wide photo of an amplitude hologram in Kodak 649F Film. [[Image:Fringes4.jpg]] Same sample zoomed into 5u wide. [[Image:Fringes2.jpg]] Phase hologram in Kodak 649F about 25u wide. [[Image:Fringes3.jpg]] Phase Hologram in Scientia 14C75 film about 25u wide. [[Image:Fringes5.jpg]] Same sample zoomed in to 5u wide. [[Image:Fringes6.jpg]] Cross section of an amplitude hologram on Kodak 649F about 30u wide. fa0e58a62971eae89244587eae579fccc7fecfb2 6 88 805 88 2006-03-12T02:08:29Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 232 311 2006-03-12T02:34:54Z Colin Kaminski 0 wikitext text/x-wiki This page is under construction! > I do have > one question, I was under the impression that the only way I could make an > isolator is with a Faraday Rotator and a polarizer. This is well out of my > budget. It is the only true isolator I know of. > However a 1/4 wave plate and a polarizer sounds easy. I just purchase 4 1/4 > wave plates from e-bay for cheap and if I can use one of them it would be > simple. > > How does a 1/4 waveplate and a polarizer function as an isolator? This is not a true isolator. It only works to block back-reflections from a mirror (or other reflective surfaces, as long as they maintain the polarization). It is simple, but not so simple to understand. When I first came across it, it took me some time, and I was standing in front of the set-up. The setup: The light goes through a polarizer, a 1/4-wave plate (oriented at 45 degrees to the polarization) and hits a mirror. There are two ways to look at it: 1. The light goes through the 1/4 plate twice (forwards and backwards), making it effectively a 1/2 plate ==> the polarization is turned by 90 degrees and cannot pass the polarizer on its way back. 2. The light goes through the polarizer and then through the 1/4 plate. The result is circular polarization. At the mirror, the light is reflected back, still in circular polarization. At the 1/4, it is converted back to linear, but at 90 degrees to its original orientation. If the reflection depolarizes the light (e.g. on a diffuse surface), it doesn't work any more. That's why it is not a true isolator, since it doesn't block arbitrary light in the reverse direction. If the reflection de-polarizes only to a certain degree (like atmospheric back-scattering, which generally de-polarizes only a little bit), then it reduces the amount getting back significantly, but doesn't block it 100%. > Holographers have a big problem with the back reflection changing when the > shutter opens. Any level of isolation would be extremely helpful. Especially > with diode lasers. So you have to look at the nature of your back-reflection. Either use one polarizer and insert and rotate the 1/4 plate to see whether it helps at all, or look through a polarizer at the back-reflected light and see whether turning it will have any effect (assuming that your laser light is polarized). If yes, the 1/4 plate will help to the same degree. However, be sure that the 1/4 plates you have are really for 635nm. Some of them are only narrow bandwidth. Anyway, maybe it is even best to play around first: use a plain mirror to reflect your laser almost back into itself (let it hit a screen next to the laser aperture just a few mm besides the aperture). Then insert the polarizer, so that the forward and reverse beams go through it. If the laser is polarized, you should see not much of an effect, if the polarizer is oriented properly. Then insert the 1/4 plate between the polarizer and the mirror and rotate it. The reflected spot should change from full power to almost non-visible within 45 degree rotation. If the polarizer is a polarizing beam splitter (like a cube), then you should see the reflected beam coming out of the side of the polarizer when it is minimum at the straight reflection. It is quite impressive, when you see it the first time. 39e3a56a4bab60b183b61ffddce88e5f445bd2b0 12 259 365 2006-03-12T04:59:06Z Colin Kaminski 0 wikitext text/x-wiki To get help on editing the HoloWiki look [[Help:Editing|here]]. To get help on holography you can ask questions [http://www.holographyforum.org/phpBB2 here]. To use Google to search this site add "site:www.holographyforum.org" to any google search. [http://www.google.com Google] 87b1ecee048787326cad92e32d4c9535f3cbc0b2 6 112 459 112 2006-03-12T17:27:16Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 111 457 111 2006-03-12T17:38:51Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 412 974 2006-03-12T17:56:13Z Colin Kaminski 0 wikitext text/x-wiki I am working on an article for this. - Colin cd0e9095f8570a0f52c686bdd77c16ae88b1a5ef 12 260 367 2006-03-12T19:05:06Z Colin Kaminski 0 /* headings */ wikitext text/x-wiki This Wiki uses a simple markup to allow for special formatting. Edit this page to see how the things below were done. Besides the buttons at the top of a edit form, there is additional formatting such as bullets for lists: * item * something else * and another thing numbered lists: # first # second # last ====headings==== (more equal signs mean smaller heading) Tables: {| | 1 || 2 || 3 |- | 4 || 5 || 6 |} Boxed text (indent with a space) Span tags for <span style="text-decoration: underline">real</span> <span style="background: yellow">power</span> users. And, lots more. See here for details: [http://languagemachine.sourceforge.net/mediawiki.html media wiki grammer] [http://meta.wikimedia.org/wiki/MediaWiki_User's_Guide:_Editing_overview Media Wiki's Overview on Editing from the Users Manual]. Here is a [[Sandbox]]. Just to try and edit what ever you want. c9b6c1de3a5b59754e21d69bb6d12b9bf03e139e 6 92 823 92 2006-03-12T22:33:34Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 8 839 8 2006-03-12T23:00:31Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 89 791 89 2006-03-12T23:01:09Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 182 211 2006-03-12T23:10:40Z Colin Kaminski 0 wikitext text/x-wiki More information can be found at [[Brewster's Angle]] and [[Polarization]]: Kaveh Posted: You want to reduce reflections between surfaces, so as not to get woodgrain. So you should make sure your reference beams are p-polarized. In this way, you will always get less reflection than s-polarized light. Now, if you want to be sure you get no reflection, then you should use p, and come in at the Brewster angle. But holography is a compromise, and always having to use Brewster is limiting. So, we can use other angles, knowing that at least we are getting less than we would with s polarization. Look at the graph showing the reflectivity of the two states: [[Image:BrewstersGraph.jpg]] At zero incidence, around 4% of all light is reflected. As we increase the angle of incidence, the reflected portion of the s light, dashed curve, steadily increases. But p decreases first, going to zero at Brewster's angle, and then increases. Now take 45 degrees. With s, you get around, say, 8% of the light reflected. With p, only around 1%. So you have dramatically reduced the unwanted reflection beams, and not used Brewster. Bob Hess posted: I'd like to share a technique I've discovered which prevents "wood grain" fringes, and increases both the brightness and "viewing zone" of image-planed reflection holograms. It's based on the material Polaroid used to make to reduce glare off computer screens, which is a circular polarizer laminated to a linear polarizer (I believe the product number was HNCP-36). I was using p-polarized light in the collimated reconstruction beam for my 30x40cm H1s, and p-polarized light in the collimated reference beam (at approximately Brewster's angle) for the H2. The system was laid out flat on the table, so that all incidence angles were parallel to the table. The problem was that the light comming from anywhere on the H1 that was out of the plane of incidence was no longer p-polarized when it hit the H2 recording plate! This effectively decreased the efficiency of the gratings formed by those rays (the skew rays) and the collimated reference beam. My solution was to use the HNCP-36 as follows: A) the HNCP-36 was cut so that the linear side was parallel to the edges of the piece (as opposed to being at 45 degrees as supplied), B) the HNCP-36 was index-matched to the emulsion side of the recording plate with the linear side toward the emulsion and oriented to pass s-polarized light, C) the reconstruction beam for the H1 was made to be circularly polarized, and D) the reference beam for the H2 was made to be s-polarized. The use of a circularly polarized H1 reconstruction beam meant that the skew rays diffracted by the H1 were also circularly polarized. This light would first encounter the circular polarizer at the recording plate, which would make them linear again. The resulting linearly polarized skew rays would then make fringes of maximum visibility with the linearly polarized reference beam, and this increased the brightness of the H2 when viewed off to the sides. The use of s-polarization at the H2 recording plate provided maximum fringe visibility regardless of the angles of incidence, therefore increasing the overall efficiency of the hologram. "Wood grain" fringes were avoided because: A) the linearly polarized reference beam passes through the linear polarizer, B) it's made to be (let's say right-handed) circular, C) reflects off the polarizer-to-air interface as (in this case left-handed) circular, D) becomes linear again after passing back through the circular polarizer (but now its polarization has been rotated by 90 degrees), and E) is absorbed by the linear polarizer before hitting the emulsion again. The downside of this technique is that it is wasteful of light. The resulting holograms, however, are brighter and stay bright all the way to the edges of the viewing zone. Also, the use of Brewster's angle is not necessary for the H2 reference beam. As Keveh pointed out, a little "wood grain" on the H1 is tolerable and the small amount that results from this technique is generally not noticed in the final image. 80ad18185278dc6302900eb3da163f9a0457f822 0 181 209 2006-03-13T03:46:51Z Colin Kaminski 0 wikitext text/x-wiki When Sir David Brewster was studying [[Polarization]] he found that at a certain angle the reflected light was completely polarized. We now call this light s-polarized. The p-polarized light is completely transmitted throught the medium. As holographers we use this method to polarize lasers by inserting a brewster's window into a laser or to minimize the reflections from a piece of glass holding our emulsion. Since out laser is completely polarized we can choose s or p polarization independently from the other. [[Image:BrewstersGraph.jpg]] A graph of reflection vs incedent angle for s-polarized (dashed Line) light and p-polarized (solid line) light. ===Brewster's Law=== [[Image:BrewstersEq.gif]] Brewster's Law calculates the angle of minimum reflection for [[Polarization|p-polarized]] light. n1 and n2 are the [[Refractive Index|refractive indicies]] of the two media. Usually for us that is 1 for air and about 1.5 for glass. So, for air at 1.00029 and glass at 1.5 we get: tan(theta)=1.5/1.00029 theta=56.3deg And then for gelatin 1.36: tan(theta)=1.36/1.00029 theta=53.66deg More information about when to use Brewster's Angle can be found [[Brewster's Discussion|here]]. ===Finding Brewster's Angle=== One way to determine Brewster's Angle is to set up your laser for [[Polarization|p-polarization]] and place a single piece of glass in it. Hit the glass with your spread beam. The glass is going to reflect some of the light hitting it, so place a white card in this reflected light path (in order to view it). If you rotate your glass plate, you will notice that this reflected light becomes brighter and dimmer. Find the spot within the rotation where the reflected light is at it's dimmest on your white card, and you've got it. With a properly-running diode, the reflection will go completely out on the card (100% -- or VERY close to 100% -- transmission through the glass). Also of interest is the angle change when a beam travels between two materials of different indicies of refraction defined by [http://en.wikipedia.org/wiki/Snells_law Snell's Law]. 1926ee1bae862fb0ec0489bff16add66cef2350c 0 450 1050 2006-03-13T05:52:12Z Colin Kaminski 0 /* Chromatic */ wikitext text/x-wiki =Spherical= Parabolic mirrors can focus light tightly, a spherical mirror produces aberrations particularly along the outer edge. =Coma= Coma is most often encountered in holography when a parabolic collimation mirror is used off-axis. =Astigmatism= When the lens is more oblong than it is spherical. It's also the most common vision problem with the human eye. =Chromatic= If a lens diffracts differnt colors in different ways, then you get chromatic abberation. The classical example is a prism that breaks white light into a rainbow of its components (ROYGBIV). Mirrors are imune from chromatic aberrations. [http://en.wikipedia.org/wiki/Aberration_in_optical_systems Wikipedia's Aberration Section] aeb2c81f568ff2554e3593bffa95bda3adeee00f 0 185 217 2006-03-13T19:30:12Z Colin Kaminski 0 Calculating Elipses moved to Calculating Ellipses wikitext text/x-wiki If you need to find the change in area between a circle and when it is tranformed into an ellipse by tilting it so that its major axis is increased. When the circular region in 3 space is rotated about one of its diameters, turning it into the new minor axis, the orthogonal radius becomes the major axis, and will be increased by the inverse of either the sine or cosine of the angle, depending on how you measure it. If the circle is just sitting there minding its own business basking in the light waves arriving along its normal, then we say it's moved 0 degrees, so we use cosine, (since cos 0 degrees = 1, otherwise we run into a problem with dividing by sin 0 = 0) because we will be dividing the other diameter's measurement by the cosine of the angle that we have rotated it. Tilting 30 degrees from the normal, the major axis grows by 1/cos 30 degrees or 1/.8660 = 1.155. Then this could be plugged into the area of an ellipse equation. Tilting more to 45 degrees gives a lengthening of the diameter by 1/.7071 or 1.414 times. Notice the areas of the new ellipses compared to the original circle are off by a factor of, you guessed, the cosine of the angle of displacement from the normal! This is why the light meter's reading is attenuated, the area of radiant flux at right angles to the beam is now spread out over a larger area of the transformed ellipse! So there are less photons per unit area! Now does everyone see the wisdom of the detector parallel to the recording material? This can also be used to calculate the area of coverage of your collimation mirror. 5cee890e45ffc680fd23af941c549a693ece58c4 10 553 1256 2006-03-13T21:58:56Z Colin Kaminski 0 wikitext text/x-wiki red 78988010b890ce6f4d2136481f392787ec6d6106 10 556 1262 2006-03-13T21:59:24Z Colin Kaminski 0 wikitext text/x-wiki green bc74f4f071a5a33f00ab88a6d6385b5e6638b86c 10 561 1272 2006-03-13T21:59:53Z Colin Kaminski 0 wikitext text/x-wiki black 466bc8cef3e71de796ec483e212724a2c2044c68 10 550 1250 2006-03-13T22:01:17Z Colin Kaminski 0 wikitext text/x-wiki <noinclude>{{colorsample|#ff99cc}}</noinclude><nowiki>#</nowiki>ff99cc db82fbc3ee828901dcd2427ddcdc364424477e9f 10 551 1252 2006-03-13T22:02:38Z Colin Kaminski 0 wikitext text/x-wiki <noinclude>{{colorsample|#ff6666}}</noinclude><nowiki>#</nowiki>ff6666 abba2ddc4c837be870a6939b2f1ebfb825dd15de 10 548 1246 2006-03-13T22:03:46Z Colin Kaminski 0 wikitext text/x-wiki <span style="display:inline-block;width:1.618ex;height:1ex;border:1px solid black;background:{{{1}}}">&nbsp;</span> 2bb3af38519ddb15c6f152fe7fccaeac5d1cdcce 10 563 1276 2006-03-13T22:04:58Z Colin Kaminski 0 wikitext text/x-wiki 1px dashed black 80745b62f37d66fe7d7b4f1940a129f4b12164fe 10 564 1278 2006-03-13T22:05:34Z Colin Kaminski 0 wikitext text/x-wiki 1px solid black 848a0ccf71e1d37b5f260d977454fdccac6b020e 10 565 1280 2006-03-13T22:06:04Z Colin Kaminski 0 wikitext text/x-wiki 1px dotted black 22d8f7f24279c23b2d7da0e3792b90119dceda15 10 566 1282 2006-03-13T22:06:32Z Colin Kaminski 0 wikitext text/x-wiki none; padding:1px 07257e0b5b8376ea25e1fd0b6804965eb6a947d7 10 567 1284 2006-03-13T22:07:12Z Colin Kaminski 0 wikitext text/x-wiki {| style="clear: both; width: 75%" align="center" class="toccolours noprint" !align="center" style="background:#ccccff"| [[Periodic table]]s |- |align="center"|<small> [[Periodic table (standard)|Standard table]] | [[Periodic table (alternate)|Vertical table]] | [[Periodic table (big)|Table with names]] | [[Periodic table (large version)|Names and atomic masses (large)]] | [[Periodic table (detailed)|Names and atomic masses (small)]] | [[Periodic table (text only)|Names and atomic masses (text only)]] | [[Periodic table (wide)|Inline F-block]] | [[Periodic table (extended)|Elements to 218]] | [[Periodic table (electron configurations)|Electron configurations]] | [[Periodic table (metals and non-metals)|Metals and non metals]] | [[Periodic table (block)|Table by blocks]] </small> |- !align="center" style="background:#ccccff"| Lists of elements |- |align="center"|<small> [[List of elements by name|Name]] | [[List of elements by symbol|Atomic symbol]] | [[List of elements by atomic number|Atomic number]] | [[List of elements by boiling point|Boiling point]] | [[List of elements by melting point|Melting point]] | [[List of elements by density|Density]] | [[List of elements by atomic mass| Atomic mass]] </small> |- |align="center" style="background:#ccccff"|[[Periodic table group|'''Groups:''']] &nbsp;&nbsp;[[alkali metal|1]] - &nbsp;[[alkaline earth metal|2]] - &nbsp;[[Group 3 element|3]] - &nbsp;[[Group 4 element|4]] - &nbsp;[[Group 5 element|5]] - &nbsp;[[Group 6 element|6]] - &nbsp;[[Group 7 element|7]] - &nbsp;[[Group 8 element|8]] - &nbsp;[[Group 9 element|9]] - [[Group 10 element|10]] - [[Group 11 element|11]] - [[Group 12 element|12]] - [[Boron group|13]] - [[carbon group|14]] - [[nitrogen group|15]] - [[chalcogen|16]] - [[halogen|17]] - [[noble gas|18]] |- |align="center" style="background:#ccccff"|[[Periodic table period|'''Periods:''']] &nbsp;[[Period 1 element|1]]&nbsp; - &nbsp;[[Period 2 element|2]]&nbsp; - &nbsp;[[Period 3 element|3]]&nbsp; - &nbsp;[[Period 4 element|4]]&nbsp; - &nbsp;[[Period 5 element|5]]&nbsp; - &nbsp;[[Period 6 element|6]]&nbsp; - &nbsp;[[Period 7 element|7]]&nbsp; - &nbsp;[[Period 8 element|8]]&nbsp; - &nbsp;[[Period 9 element|9]] |- |align="center" style="background:#ccccff"|[[Chemical series|'''Series:''']] &nbsp; [[Alkali metal|Alkalis]]&nbsp; - &nbsp;[[Alkaline earth metal|Alkaline earths]]&nbsp; - &nbsp;[[Lanthanide]]s&nbsp; - &nbsp;[[Actinide]]s&nbsp; - &nbsp;[[Transition metal]]s&nbsp; - &nbsp;[[Poor metal]]s&nbsp; - &nbsp;[[Metalloid]]s&nbsp; - &nbsp;[[Nonmetal]]s&nbsp; - &nbsp;[[Halogen]]s&nbsp; - &nbsp;[[Noble gas]]es |- |align="center" style="background:#ccccff"|[[Periodic table block|'''Blocks:''']]&nbsp; [[s-block]]&nbsp; - &nbsp;[[p-block]]&nbsp; - &nbsp;[[d-block]]&nbsp; - &nbsp;[[f-block]]&nbsp; - &nbsp;[[g-block]] |} [[Category:Periodic table]] 444432fbf1179260ba9c5d9330be8ec05abe0014 10 562 1274 2006-03-14T02:10:18Z Colin Kaminski 0 wikitext text/x-wiki <noinclude>{{colorsample|#ffc0c0}}</noinclude><nowiki>#</nowiki>ffc0c0 643c40505b09e82dfc638a5091d598bf1b5aff72 10 560 1270 2006-03-14T02:11:52Z Colin Kaminski 0 wikitext text/x-wiki <noinclude>{{colorsample|#cccccc}}</noinclude><nowiki>#</nowiki>cccccc 4489dec08e71c72196bf5383a287a1c4d93b3616 10 559 1268 2006-03-14T02:12:39Z Colin Kaminski 0 wikitext text/x-wiki <noinclude>{{colorsample|#a0ffa0}}</noinclude><nowiki>#</nowiki>a0ffa0 03a2c416f259bb45faaf3ec0308abc91f440ad16 10 558 1266 2006-03-14T02:13:34Z Colin Kaminski 0 wikitext text/x-wiki <noinclude>{{colorsample|#c0ffff}}</noinclude><nowiki>#</nowiki>c0ffff 526be33f65f14c64eeadfe0e72373ab2f055fe23 10 557 1264 2006-03-14T02:14:15Z Colin Kaminski 0 wikitext text/x-wiki <noinclude>{{colorsample|#cccc99}}</noinclude><nowiki>#</nowiki>cccc99 d2ef6a2a1221f869841b37e222b8bca9b76d70d6 10 555 1260 2006-03-14T02:18:10Z Colin Kaminski 0 wikitext text/x-wiki <noinclude>{{colorsample|#ffbfff}}</noinclude><nowiki>#</nowiki>ffbfff 6ddcb3f41d5c32406d9b27e809494bc3fda90ffc 10 554 1258 2006-03-14T02:18:52Z Colin Kaminski 0 wikitext text/x-wiki <noinclude>{{colorsample|#ffff99}}</noinclude><nowiki>#</nowiki>ffff99 ea826ba8176d2be9b63e3ba5fa76acd47abbed61 10 552 1254 2006-03-14T02:19:43Z Colin Kaminski 0 wikitext text/x-wiki <noinclude>{{colorsample|#ffdead}}</noinclude><nowiki>#</nowiki>ffdead 90b48d49c7143026f874740eb2838046ddb8da23 1 524 1198 2006-03-14T02:45:42Z Phil Edelbrock 0 wikitext text/x-wiki I wonder if you should preface this with a basic sentence or two of what Brewster's Angle is? Personally, I thought it was the incedence angle where total internal reflection occurs. Like being under water and looking at a slight angle at the (calm) water/air boundry and getting a nice mirror effect. Or how light in a fiber optic can travel so far bouncing so many times off the internal boundries. In general, nice technical information on the wiki in, btw. I'm learning so much more now just going through the pages! -Phil ---- Does that make more sense? I also added a link to Snell's Law at the bottom to cover total internal reflection. ---- Yeah. Wow, an incredible amount of work going on Colin. -Phil 064a339cd0452d4a64476ee7875b273a780454de 10 549 1248 2006-03-14T03:38:25Z Colin Kaminski 0 wikitext text/x-wiki title="{{{6|}}}; {{{7|}}}; {{{5|}}}" style="text-align:center; color:{{element color/{{{5|Solid}}}}}; background:{{{9|{{element color/{{{6|Transition metals}}}}}}}}; border:{{element frame/{{{7|Primordial}}}}};" | {{{1}}} <br> {{{8|{{{2}}}}}}|{{{3}}} b046b188ed3d1ccf4fc140e3b2349abc35210605 6 16 889 16 2006-03-14T05:13:12Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 476 1102 2006-03-14T14:38:27Z Colin Kaminski 0 wikitext text/x-wiki The refractive index is a dimentionless quantity that measures the speed of light in the material. It is defined as the ratio of the speed of light in a vacuum to the speed of light in the material and is usually signified by the letter n. n=c(vacuum)/c(mat) ==Mixing Two Chemicals to Get a new Refractive Index== If you need a different refractive index two '''compatible materials''' can be mixed the new refractive index would be: P1/100 = (n(new) - n2) / (n1 - n2) where P1 denotes the volume percent of component 1, n1 is the index of component 1, n2 that of component 2, and n(new) that of the mixture. (Hanz Bjelkhagen). ==Choosing the best Refractive Index== The optimum Refractive Index for matching two materials is given by the equation (the geometric mean): n(optimum)=sqrt((n0)(n1)) Large deviations are posible so don't kill youself trying to get the exact one. ==Refractive Indices== Here are some available index matching fluids for reference (could be helpful for liquid filled lenses as well). There are some scary chemicals here so get the MSDS before you use them and follow all recomended procedures: *Methyl Alcohol 1.328 *Water 1.335 *Freon-113 1.358 *Gelatin 1.36 (8 grams in 50 ml of water) *Paraffin (Lamp Oil) about 1.4 *l-Butanol, 3 methyl 1.405 *Kodak Dispersant MX-1320 1.420 *Stoddard Solvent 1.435 *Methyl Chloroform 1.438 *Kerosene 1.460 *Carbon Tetrachloride 1.461 *Decalin Solvent 1.475 *Glycerin 1.475 *Mineral Oil 1.475 *Trichloroethene 1.494 *Tetrachloroethane 1.494 *Diethylbenzene 1.496 *Toluene 1.496 *p-Xylene 1.496 *Di-n-butyl phthalate 1.497 *Xylene (commercial) 1.499 *Glass (common) 1.5 *Tatrachloroethylene 1.504 *o-Xylene 1.506 *Pyridine 1.509 *Dimethylphthalate 1.515 *Benzyl ether 1.517 *b-Ionone 1.520 *Ethyl benzoil acetate 1.523 *Chloro benzene 1.524 *Methyl salicylate 1.536 *Benzyl benzoate 1.570 *Bromo naphthalene 1.658 Refractive index shown at 20C. From Silver-Halide Recording Materials for Holography and Their Processing by H.I. Bjelkhagen except Paraffin, glass, water and gelatin ca23097cddbc111c5c5093db69e739baca8ff262 6 71 755 71 2006-03-16T01:27:11Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 61 735 61 2006-03-16T01:27:46Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 72 757 72 2006-03-16T01:28:44Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 74 761 74 2006-03-16T01:29:12Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 64 743 64 2006-03-16T01:45:16Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 62 739 62 2006-03-16T02:18:07Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 73 759 73 2006-03-16T02:20:22Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 63 741 63 2006-03-16T02:21:22Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 65 745 65 2006-03-16T02:24:38Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 66 747 66 2006-03-16T02:27:23Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 67 749 67 2006-03-16T02:28:35Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 68 751 68 2006-03-16T02:29:30Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 69 753 69 2006-03-16T02:30:36Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 70 737 70 2006-03-16T02:31:20Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 150 563 150 2006-03-16T04:12:02Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 244 335 2006-03-16T04:15:24Z Colin Kaminski 0 wikitext text/x-wiki [[Image:GLippmann.jpg]] French physicist who received the Nobel Prize for Physics in 1908 for producing the first colour photographic plate . He was known for the innovations that resulted from his search for a direct colour-sensitive medium in photography. Though born of French parents in Luxembourg, Lippmann grew up in Paris and was a bright but unruly student. Despite the fact that he never received his teacher's certificate, he was appointed professor of mathematical physics at the Sorbonne in 1883. He later was appointed head of the Sorbonne's Laboratories of Physical Research (1886). Lippman's scientific talents were varied, but he was best known for his contributions in the fields of optics and electricity. He did early, important studies of piezoelectricity (precursors of Pierre Curie's work) and of induction in resistanceless, or superconductive, circuits (precursors of Heike Kammerlingh-Onnes' validations). He also invented the coleostat, an instrument that allowed for long-exposure photographs of the sky by compensating for the Earth's motion during the exposure. In 1891 Lippmann revealed a revolutionary colour-photography process, later called the Lippmann process, that utilized the natural colours of light wavelengths instead of using dyes and pigments. He placed a reflecting coat of mercury behind the emulsion of a panchromatic plate. The mercury reflected light rays back through the emulsion to interfere with the incident rays, forming a latent image that varied in depth according to each ray's colour. The development process then reproduced this image, and the result, when viewed, was brilliantly accurate. This direct method of colour photography was slow and tedious because of necessarily long exposure times, and no copies of the original could be made. It never achieved popularity, therefore, but it was an important step in the development of colour photography. [http://nobelprize.org/physics/laureates/1908/lippmann-bio.html Nobel Prize's Biography of Gabriel Lippmann] b263f6cbbc8d8b6541b90b344f273c27ea052fc8 1 529 1208 2006-03-16T04:19:29Z John Pecora 0 wikitext text/x-wiki Wow, this page is getting long. I think we'll need to split it out soon into seperate pages. I'm also getting conflicts as I'm editing while somebody else is too. Great work! -Phil ---- Yes, we need to cut it up. I think we can make all of the main sections into new pages. I was editing right ahead of you. I'll watch and work on different sections until I find a better way. Have you been looking at the recent changes page? It allows you to see who has been working where. - Colin ---- Hi Colin. Yes, I've been looking at the recent pages more now. This is great stuff here in the wiki. Finally things that can be contributed that aren't slipping off the bottom of the page. The good stuff gets accumulated instead of diluted and forgotten! -Phil ---- I see that recording materials is it's own set of pages. It seems like it should be part of the Technology heirarchy in the same style as however this information ends up after being diced up. -Phil ---- This is great. I took a first step and someone took it to the next level. I LIKE IT! Great work! JFP ddb853c288db0287b6d32257abf86d1335d6db06 6 86 795 86 2006-03-16T04:30:23Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 87 797 87 2006-03-16T04:35:02Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 475 1100 2006-03-16T23:37:19Z Colin Kaminski 0 wikitext text/x-wiki There are literally thousands of articles about holography in the technical journal. 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Retrieved from "http://www.holographyforum.org/HoloWiki/index.php/Copyright" 675d9b98a219bca068f6ccc95fa6fdbd2d164f84 6 50 713 50 2006-03-17T20:42:42Z Phil Edelbrock 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 51 715 51 2006-03-18T15:30:36Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 34 663 34 2006-03-18T18:09:34Z Wolfgang 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 113 471 113 2006-03-18T18:19:13Z Wolfgang 0 Shows how laser spectrum and coherence length correspond to each other. wikitext text/x-wiki Shows how laser spectrum and coherence length correspond to each other. d8ef75d6b7794702e6845e6ee6f23cba1da42a72 6 52 717 52 2006-03-19T01:48:34Z Phil Edelbrock 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 2 584 1318 2006-03-19T01:56:44Z Phil Edelbrock 0 wikitext text/x-wiki Welcome to the [http://www.holographyforum.org Holography Forum's] Holography Wiki. <span style="position: absolute; left: 25px; top: 100px">http://www.holographyforum.org/HoloWiki/images/Laser-bulb8.jpg</span> <!-- left column --> <span style="position: absolute; left: 45px; top: 120px; font-size: 16pt; line-height:100%">[[Holography for Beginners|____________]]<br /> <span style="font-size: 12pt; color: #cef7f4;">faq for beginning holographers</span> </span> <span style="position: absolute; left: 45px; top: 205px; font-size: 16pt; line-height:100%;">[[Holography Glossary|_______]]<br /> <span style="font-size: 12pt; color: #cef7f4;">technical terms defined</span> </span> <span style="position: absolute; left: 45px; top: 290px; font-size: 16pt; line-height:100%;">[[Holography Links|_____]]<br /> <span style="font-size: 12pt; color: #cef7f4;">other web resources</span> </span> <span style="position: absolute; left: 45px; top: 375px; font-size: 16pt;line-height:100%;">[[Biographies of Holographers|__________]]<br /> <span style="font-size: 12pt; color: #cef7f4;">people who have made <br>it all possible</span> </span> <span style="position: absolute; left: 45px; top: 460px; font-size: 16pt; line-height:100%;">[[History of Holography|______]]<br /> <span style="font-size: 12pt; color: #cef7f4;">documenting<br> the people and events</span> </span> <!-- Right column --> <span style="position: absolute; left: 353px; top: 120px; font-size: 16pt; width:225px; text-align:right; line-height:100%;">[[Hologram Recording Materials|________________]]<br /> <span style="font-size: 12pt; color: #cef7f4;">how to get or make them</span> </span> <span style="position: absolute; left: 353px; top: 205px; font-size: 16pt; width:225px; text-align:right; line-height:100%;">[[Holography Safety|_____]]<br /> <span style="font-size: 12pt; color: #cef7f4;">chemical and <br>laser information</span> </span> <span style="position: absolute; left: 353px; top: 290px; font-size: 16pt; width:225px; text-align:right; line-height:100%;">[[Holography Theory|______]]<br /> <span style="font-size: 12pt; color: #cef7f4;">mathematics and science</span> </span> <span style="position: absolute; left: 353px; top: 375px; font-size: 16pt; width:225px; text-align:right; line-height:100%;">[[Holography Technology|_________]]<br /> <span style="font-size: 12pt; color: #cef7f4;">hardware and setups</span> </span> <span style="position: absolute; left: 353px; top: 460px; font-size: 16pt; width:225px; text-align:right; line-height:100%;">[[Lippmann Photography|______________]]<br /> <span style="font-size: 12pt; color: #cef7f4;">color photographs<br>made with diffraction patterns</span> </span> <!-- keep these blank lines. Sorry, it the only way I know how to keep the rest of the wiki page below the image --> <!-- create plenty of empty space--> [[What is a Wiki?]] ---- This project is only possible with the generous time and support of the authors. In order to obtain a login to edit the HoloWiki please contact [[Colin Kaminski]]. 695f66dcc7606966e16dbc6469808bfded740f9c 0 264 375 2006-03-19T03:14:12Z Colin Kaminski 0 wikitext text/x-wiki Sharing information is the reason that a group of holographers has joined together. It started at the [http://www.holographyforum.org Holography Forum]. The holography forum was created on July 1st 2002, since that time we've posted more than 30,000 posts. The forum and HoloWiki Director is [[Colin Kaminski]]. We also have created a sister organization called the [http://www.pcgholography.com PCG] now run and maintained by [[Michael Harrison]]. It's purpose is to carry our momentum off the web and into the real world. We do this through meetings and outreach. 981e9e0bd1c3b56799e1992bcb39fdcc10249c5b 0 262 371 2006-03-19T03:27:58Z Colin Kaminski 0 wikitext text/x-wiki The Holowiki is the off-shoot of the [http://www.holographyforum.org Holography Forum]. Since we started we have generated more than 30,000 posts and found we were talking about some of the same things again and again without reference to the information we had dug up the last time we read it. [[Phil Edelbrock]] came up with the great idea of starting a "small wiki". What you see now has taken 100's of hours of work looking through old posts and writing new information. The Holowiki logo in the upper right corner was drawn in pencil by Tim ???? in Napa, CA. It was drawn life size then scanned and reduced. The Light Bulb Logo on the main page was the brain child of [[Phil Edelbrock]]. He took three photos of his HeNe laser shining on a light bulb and used photoshop to shift the colors to three make it look like 3 different lasers. When the three images were superimposed the lightbulb was white without adjustment. He then wrote the code for the positioning of the titles on the main page. [[What is a Wiki?]] dc5e14ce94779cb6ab267825de7a069f47f4e426 6 114 473 114 2006-03-19T09:58:28Z Wolfgang 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 80 777 80 2006-03-21T15:51:56Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 533 1216 2006-03-21T16:20:13Z Colin Kaminski 0 wikitext text/x-wiki I have a suggestion for the illustration. It looks like the object on the left is something between two mirrors and the two mirrors are movable in and out. I assume, but I may be wrong, that it is a resonator??? I think if it is just a laser, remove the two mirrors and the double arrow. If it is something else I am misinterpreting, maybe a small blurb below the image may help. In a Michelson, usually only one leg would want to be moved in an out...NO? JohnFP ---- I uploaded a temporary one. I'll make a better one later. ---- ffb4b5b7fb51634de4abda93fc5f32d185fabcc8 0 156 159 2006-03-22T15:43:01Z Colin Kaminski 0 wikitext text/x-wiki ==Holography Glossary== [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Aerial perspective''' - the distance or depth effect caused by atmospheric haze. Haze creates a large amount of extraneous ultra-violet light to which all photographic emulsions are sensitive. *'''Acetic acid''' - chemical used for stop baths and to acidify acid fixing solution. *'''Acetone - solvent chemical used in certain processing solutions that contain materials not normally soluble in water.''' *'''Albumen paper''' - printing paper invented by Blanquart-Evrard in the mid-19th century where egg whites were used to coat the paper base prior to sensitization. The albumen added to the brightness of the white base and substantially improved printed highlights. *'''Allegory''' - work of art that treats one subject in the guise of another. An allegoric photograph usually illustrates a subject that embodies a moral "inner meaning". *'''Alum''' - chemical used in acid hardening fixing baths. *'''Aluminum compounds''' - groups of chemicals often used as hardeners in fixing baths. *'''Ambrotype''' - Mid-19th century photographic process introduced in 1851-52 by Frederick Scott Archer and Peter Fry. It used weak collodion negatives which were bleached and backed by a black background which produced the effect of a positive image. *'''Amidol''' - soluble reducing agent which works at low pH values. *'''Ammonium chloride''' - chemical used in toners and bleachers. *'''Ammonium Dichromate''' - chemical used as a sensitizer in Dichromated Holograms. *'''Ammonium persulfate''' - chemical used in super-proportional reducers. *'''Ammonium sulfide''' - pungent but essential chemical in sulfide or sepia toning. *'''Ammonium thiosulfate''' - highly active fixing agent used in rapid fixing solutions which works by converting unused silver halides to soluble complexes. *'''Amphitype''' - Mid-19th Century process based on an underexposed albumen-on-glass negative. This was viewed by reflected light against a black background to give a positive image similar to a ambrotype. *'''Anaglyph''' - result of forming stereoscopic pairs from two positives each dyed a different color, usually green or red. *'''Antiscreen plates''' - photographic plates containing dyes that reduce the blue sensitivity. Used unfiltered, they can give results similar to those obtained with yellow filtered orthochromatic plates. *'''Apodization''' - lens treatment designed to cut down diffraction fringes that appear around the images bright points of light. *'''Aquatint''' - etching technique allowing control of tonal areas to produce almost unlimited gradations from pale gray to black. Because of this it has also been used in photography as an alternative term for gum bichromate process. *'''Argentotype''' - Mid-19th century silver print process, on which the kallitype and sepia paper processes are based. *'''Aristotype''' - early commercial print type made on collodion-chloride or gelatin-chloride paper. *'''Azo dyes''' - compounds forming colors of great strength and purity. Used in camera filters and integral tripack dye-bleach materials. a5cb819f9093313bb4b2d3fd43ab62ac8397cf3c 0 174 195 2006-03-22T15:44:08Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Ballistic photography''' - photography of weapons, ammunition and projectiles usually used for analysis. *'''Baryta''' - coating of barium sulfate applied as the foundation to fiber based printing papers. *'''Base-relief''' - photographic image effect usually produced by printing from a negative and a positive sandwiched together in the enlarger, slightly out of register. *'''Belitski's reducer''' - solution used as a chemical reducer for negatives. It consists of ferric potassium citrate or oxalate in an acid fixing solution. *'''Bichromate''' - refers to potassium bichromate or potassium dichromate, used for bleaching and as a sensitizer for gelatin. *'''Bitumen''' - hydro-carbon which hardens by the action of light. It was used by Joseph Nicephore Niepce to produce the worlds first photograph in the early 19th century. *'''Black silver''' - finely divided metallic silver formed from silver halides by exposure and development. *'''Bleach''' - chemical bath capable of rehalogenizing black metallic silver. *'''Bleaching''' - stage in most toning, reducing and color processing systems. *'''Bleach-out''' - method of producing line drawings from photographic images. The photographic is processed in the normal way, its outlines sketched, and the black metallic silver image is then bleached away to leave a drawn outline. *'''Blocked up''' - a portion of an overexposed and/or overdeveloped negative so dense with silver halides that texture and detail in the subject are unclear. *'''Blocking out''' - method of painting selected areas of a negative with an opaque liquid on the non-emulsion side. Since light is unable to penetrate these areas they appear white on the final print. *'''Borax''' - mild alkali used in fine grain developing solutions to speed up the action of the solution. *'''Boric acid''' - compound used in certain fixers to prolong shier hardening life. *'''Brightfield''' - method of illumination used in photomicrography which will show a specimen against a white or light background. *'''Brilliance''' - intensity of light reflected from a surface. It is sometimes an alternative term for luminosity. *'''Brometching''' - obsolete, special method of producing a bromide print. The result acquired the texture of its support and appeared similar to an etching. *'''Bromide paper''' - most common type of photographic printing paper. It is coated with an emulsion of silver bromide to reproduce black & white images. *'''Bromoil process''' - old printing process invented in 1907, consisting of three stages. First, an enlargement is made on bromide paper and processed. Second, the silver image is removed in a bleacher which also modifies the gelatin so it will accept lithographic ink. Third, while still damp the gelatin is inked up by hand to create the image. *'''Brush development''' - method of development in which developer is applied to the material with a brush or similar instrument. *'''Buffer''' - chemical substance used to maintain the alkalinity of a developing solution, particularly in the presence of bromine which is produced during development. *'''Butterfly lighting''' - lighting in which the main source of light is -placed high and directly in front of the subject. 68bb4c1b7d60cf1cff2941ba68af55788a19a94f 0 183 213 2006-03-22T15:44:35Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Callier effect''' - contrast effect in photographic printing caused by the scattering of directional light from an enlarger condenser system. The negative highlights are of high density and scatter more light with little or no scattering from negative shadow areas, which are of low density. This gives a print higher contrast than a contact print. *'''Calotype process''' - first negative/positive process, invented by W.H. Fox Talbot in 1839. Paper was coated with silver iodide and a solution of silver nitrate and gallic acid. After exposure the paper was developed in a silver nitrate solution. *'''Camera lucida''' - lens and prism system through which a virtual image was seen, apparently appearing on the surface of the drawing paper. *'''Camera obscura''' - origin of the present day camera. In its simplest form it consisted of a darkened room with a small hole in one wall. Light rays could pass through the hole to transmit on to a screen, and inverted image of the scene outside. It was first mentioned by Aristotle in the 4th Century B.C. and developed through the centuries as an aid to drawing. *'''Canada balsam''' - liquid resin with a refractive index similar to glass. It is used for bonding elements in compound lenses. *'''Candid pictures''' - unposed pictures of people and animals, often taken without the subject's knowledge. These usually appear more natural and relaxed than posed pictures. *'''Carbon process''' - contact printing process, introduced in 1866, using tissue coated with pigmented gelatin. The paper was sensitized in potassium bichromate and contact printed behind a negative in sunlight. *'''Carbon tetrachloride''' - liquid used for removing grease and finger prints from negatives. *'''Carbro process''' - early color print process using an adaptation of the carbon printing process. *'''Carte-de-visite''' - portrait photograph on a mount about the size of a postcard. Introduced in 1854, carte-de-visite became a social craze in many countries during the 1860s. *'''Cast''' - overall bias toward one color in a color photograph. *'''Caustic potash''' - high alkaline used in high contrast developing solutions to promote vigorous development. Highly corrosive and poisonous. *'''Chemical vapor''' - method of exposing negatives in a closed container to a small amount of mercury of sulfur dioxide. After approximately 24 hours the film is developed normally. It produces interesting yet very inconsistent results. *'''Chiaroscuro''' - light and shade effect. The way in which objects can be emphasized by patches of light, or obscured by shadow. *'''Chlorhydroquinone''' - developing agent contained in warm tone developers. *'''Chloride paper''' - printing paper with a silver chloride emulsion. Much less sensitive than bromide paper. Mainly used for contact printing. *'''Chromogenic development''' - process in which the oxidation products of development combine with color couplers to form dyes during processing. *'''Chlorobromide paper''' - photographic paper coated with an emulsion made up of both silver chloride and silver bromide. Used for producing enlargements with a warm, slightly brownish-black image, especially if processed in a warm tone developer.*'''Chronocyclograph''' - photograph used for the analysis of complex cyclic movements. *'''Chlorquinol''' - alternate term for chlorhydroquinone. *'''Chrome alum''' - alternative term for potassium chromium sulfate. *'''CIE standard''' - system of standards adopted by the Commission Internationale de I'Eclairage, allowing accurate descriptions of colors. *'''Clayden effect''' - desensitizing of an emulsion by means of exposure to a strong, brief flash of light. *'''Clearing agent''' - processing solution used to remove stains or to cancel out the effect of chemicals left on the sensitive material left from previous stages in the process. *'''Cliche-verre''' - designs painted on glass in varnish or oil paint, or scratched into the emulsion of a fogged and processed plate using an etching needle. The results are then printed or enlarged on photographic printing paper. *'''Collage''' - composition employing various different materials combined with original artwork attached to some type of backing. *Collodion - soluble gun-cotton, dissolved in a mixture of ether and alcohol. *'''Collodion process''' - also known as "wet collodion" was invented by Frederick Scott Archer in 1851-52. It was a great improvement over the earlier calotype process because because of the large increase in speed gained by exposing the plate while still "wet", but it had the disadvantage of requiring bulky equipment. *'''Color toning''' - system of changing the color of a black and white photograph by converting black metallic silver into a colored compound. *'''Combination printing''' - producing a composite image by printing more than one negative on a single sheet of paper. *'''Compensating positive''' - image on translucent material that can be printed together with the negative of the same image. When combined the result makes printing contrasty negatives easier. *'''Constructivism''' - art movement that begun in Russia c. 1913. Characterized by the use of everyday materials in abstract compositions. *'''Contact screen''' - type of half-tone screen in which the dots consist of slightly unsharp halos. Used to make half-tone images. *'''Contour film''' - special print film producing a equidensity line image from a continuous tone negative or print. *'''Contre-jour''' - backlighting. A photograph taken with the camera pointed directly at the light source. *'''Copper chloride''' - chemical contained in certain bleaches, toners, intensifiers, and reducers. *'''Copper sulfate''' - chemical contained in certain bleaches, toners, intensifiers, and reducers. *'''Copper toning''' - chemical process used for toning monochrome prints. *'''Coving''' - plain curved background which has no edges, corners or folds and gives the impression of infinity. *'''Cubism''' - early twentieth century European art movement characterized by the rendering of forms as simplified planes, lines and geometric shapes. 2d7e2101e3abc4d14ba6c9ba4e4e033ca7f03586 0 203 253 2006-03-22T15:44:55Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Daguerreotype''' - first practical and commercial photographic process, introduced by Louis Daguerre in 1839. The sensitive material comprised silver iodide, deposited on a polished silver plated copper base. A positive image was produced by camera exposure and mercury "development", which turned light struck halides gray-white. The image was made permanent by immersing the plate in a solution of sodium chloride. *'''Daylight enlarger''' - early type of enlarger using light from a hole in a window to provide illumination of the negative. *'''Desensitizing''' - reducing an exposed emulsion's sensitivity to light. This can be done by the application of dyes or by using oxidation agents *'''Developer''' - chemical bath containing reducing agents, which converts exposed silver halides to black metallic silver, making the latent image visible. *'''Development''' - process of converting exposed silver halides to a visible image. *'''Diazo''' - abbreviation of diazonium compounds, which decompose under the action of intense blue or ultraviolet radiation, forming an image in an azo dye. *'''Dichroic filters''' - produced by metallic surface coatings on glass to form colors by interference of light. Used in high quality color enlarger heads. *'''Dichroic fog''' - purple-green bloom usually seen on negatives and caused by the formation of silver in the presence of an acid. *'''Dilution''' - reduction in the strength of a liquid by mixing it with an appropriate quantity of water. *'''Dimensional stability''' - substance's ability to remain unchanging in size when subjected to processing and drying. *'''Dish development''' - method of development used for processing single sheet, cut film or paper by immersing in a shallow dish of developer and agitating by rocking the dish. *'''Documentary photography''' - taking of photographs to provide a record of social and political situations with the aim of conveying information. *'''Dodging''' - control of exposure in photographic printing achieved by reducing exposure to specific areas of the paper. *'''Dry down''' - refers to the amount a print darkens after drying. *'''Dry mounting''' - method of attaching prints to mounting surfaces by heating shellac tissue between the mount and the print. *'''Dye destruction process''' - method of producing a colored image by partially bleaching fully formed dye layers incorporated in the sensitive material. *'''Dye-image monochrome films''' - black & white negative films designed for color processing. *'''Dye sensitizing''' - defined as all silver halides used in black & white emulsions are sensitive to blue light. Early photographic materials possessed only this sensitivity.''' *'''Dye transfer print''' - method of producing color prints via three color separation negatives. Negatives are used to make positive matrixes, which are dyed in subtractive primaries and printed in register. *'''Dynamism''' - picture structuring which relates to a sense of movement and action. 30e028a8809dbdd048e71dc51206b2594f192e7a 0 220 287 2006-03-22T15:45:24Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Eberhard effect''' - border effect occurring in a developed image. It appears as a dense line along an edge of high density and as a light line along an edge of low density. It occurs most often in plates developed flat in solution that is not sufficiently agitated. The effect was described by Gistav Eberhard in 1926. *'''Electrophotography''' - creation of images by alteration to the electrical properties of the sensitive material as a result of the action of light. *'''Elon''' - another term for Methylaminophenol sulfate. It is more commonly known as metol. *'''Emulsion''' - light sensitive material which consists of a suspension of silver halides in gelatin. *'''Endoscope''' - optical device allowing the viewing and photography of small inaccessible subjects. *'''Evenescent Wave''' - "Tending to Vanish" - A wave whose intensity decays as an exponetial of distance. (As opposed to sinsusoidally.) *'''Exposure latitude''' - amount by which it is possible to over or underexpose a light sensitive material and, with standard processing, still produce acceptable results. a26eede8a1e43a4d73ca02e8c53edc87d5ffaac8 0 230 307 2006-03-22T15:45:56Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Factor''' - number that tells how many times exposure must be increased in order to compensate from loss of light. *'''Fahrenheit scale''' - scale of temperature named after its German originator, G. D. Fahrenheit. On this scale, the freezing point of water is 32° F, and the boiling point of water is 212° F. F=(C*(9/5))+32 *'''False attachment''' - part of one object seen behind another so that lines, shapes or tones seem to join up. A composition device used in various ways to produce images in which foreground and background objects appear to occupy the same plane. *'''Farraday shutter''' - high-speed shutter using a pair of crossed polarizers, between which is a glass block within a coil. When a voltage passes through the coil, the plane of polarization changes, allowing light to pass through the second polarizer. *'''Ferric chloride''' - bleaching solution used on negative materials. *'''Ferrotype process''' - method of creating direct positive images with dark enameled metal plates as a base. Also known as the tin-type process. *'''Film characteristic curve''' - describes a graphical relationship between the logarithm of the exposure value (horizontal axis) and density (vertical axis) of film. Each brand of film exhibits a different characteristic curve. *'''Finality development''' - prolonged development, reducing silver halides affected by light to silver until no further image density improvement occurs. *'''Flashing''' - briefly and evenly exposing photographic materials to white light.Often used to lower contrast of printing paper, when the flashing exposure is made in addition to the regular exposure. *'''Fluorescent whites''' - brilliant highlights produced by applying a fluorescent agent to a printing paper base. The print can also be treated after washing with a fluorescent whitener or dye solution. *'''f numbers''' -e numbers on the lens barrel indicating the size of the aperture relative to the focal length of the lens. f numbers are calculated by dividing the focal length of the lens by the effective diameter of the aperture. *'''Fogging''' (Fog) - produces an overall veil of density on a negative or print, which does not form part of the image. It can be achieved by chemicals or exposing the sensitive material to light. *'''Frilling''' - wrinkling and separation of the emulsion along the edges of its support material. *'''Futurism''' - art movement started in Italy c. 1910, characterized by an aggressive rejection of tradition, and the representation of the dynamic movement of machinery. 675feb945f4e4838bfbcf024b58f52d88dc8e935 0 471 1092 2006-03-23T03:58:25Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Quantum''' - smallest indivisible unit of radiant energy. '''Quarter Wave Plate''' - a optical element used to convert polarization in between circular and linear. '''Quarterplate''' - negative or print format measuring 3 * x 4 * inches. It's one quarter the size of a full plate (8 * x 6 * inches). '''Quartz-iodine lamp''' - compact tungsten filament lamp designed to maintain its color temperature and light intensity throughout its working life. 5394f9cbfbea88600a65b95086787f3632311972 0 579 1308 2006-03-23T04:00:26Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Ultrasonic image recording''' - image formation by measurement of ultrasound echoes translated electronically into a scanned visual image on a TV display. Also known as sonography. '''Ultraviolet''' (UV) - part of the electromagnetic spectrum from about 400nm down to 1nm. It is invisible to the human eye, but most photographic materials are sensitive to near UV bands down to 250nm. It records as increased haze, particularly in distant views and at high altitudes, and may give a blue cast in color images. technique of projecting an infrared image on a phosphorescent surface. '''Under-development''' - reduction in the degree of development. It is usually caused by shortened development time or a decrease in the temperature of the solution. It results in a loss of density and a reduction in image contrast. '''Underexposure''' - result of too little exposure in the camera or at the enlargement stage. '''Uprating''' - no longer used term to define the process of increasing the manufacturers film speed by the use of: hypersensitizing; using specially prepared proprietary developers; or by a two stage process. 4dcf77af541310dc4d0f3a0cd072017c7f8a63ce 0 587 1324 2006-03-23T04:00:52Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Vacuum back''' - a camera back with a perforated plate through which air is drawn by a pump. A sheet of film is therefore sucked flat against the plate and held firmly during exposure. Used for special large format cameras such as copying devices where dimensional accuracy is critical. '''Vacuum easel''' - a compact printing frame which ensures firm contact between the film and paper by excluding air between the surfaces. Some types are used to hold the paper flat on the enlarger baseboard when enlarging. '''Vanishing point''' - the point at which parallel lines, viewed obliquely, appear to converge in the distance. '''Vapor discharge lamp''' - a lamp in which electrical current passes through a vapor or gas rather than through a wire filament, thus producing illumination. '''Veil''' - a uniformly distributed silver deposit in a photographic image, not forming part of the image itself. Also known as fog. '''Video still camera''' - a camera using an electronic charge coupled device instead of film. '''View camera''' - a large format camera which has a ground glass screen at the image plane for viewing and focusing. '''Viewfinder''' - a system used for composing and sometimes focusing the subject. There are several types: direct vision, optical, ground glass or reflex. '''Viewpoint''' - the position of the camera in relation to the subject. '''Vignetting''' - a printing technique where the edges of the picture are gradually faded out to black or white. It also refers to a fall off in illumination at the edge of an image, such as may be caused by a lens hood or similar attachment partially blocking the field of view of the lens. '''Vinyl film''' - an emulsion coating on a polyvinyl chloride acetate base, with less shrinkage than conventional film bases. '''Viscose sponge''' - a synthetic sponge used to wipe surplus water off films before they are hung up to dry. '''Viscous processing''' - a process using chemicals carried in sticky semifluid substances instead of normal liquids. Used for instant picture processing. '''Volt''' - a unit of electrical potential difference and electromotive force. '''Voltage stabilizer''' - a transformer used to produce a steady output voltage despite fluctuations of input voltage. '''Vortograph''' - an abstract photograph made with a simple kaleidoscopic apparatus, first used by Alvin Langdon Coburn in 1917. cb1edb2aeb798e7f2604e45d5b0cd44819870a71 0 590 1330 2006-03-23T04:01:21Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Warm colors''' - any colors which, by association, suggest warmth, such as red, orange and yellow. '''Washing''' - the final part of the processing cycle, which removes residual chemicals and soluble silver complexes from the emulsion. '''Water bath''' - large water filled containers used to maintain processing trays, tanks or chemicals at the correct temperature. '''Water softeners''' - used to eliminate most of the minerals and slats found in hard water. '''Watkins factor''' - an old system of development control, based on observation of the processing image under safe lights. '''Watt''' - a unit of power in electricity. '''Watt-second''' - an alternative unit of energy, equal to the joule. '''Wavelength''' - the distance from wave-crest to wave-crest between two corresponding waves of light in the electro-magnetic spectrum. Wavelengths are measured in nanometers (nm) and Angstrom units (A). '''Waxed paper process''' - an early form of photography. A variation on the calotype process. '''Weak''' - a negative or print which is low in contrast or density. '''Wedge spectrogram''' - an indication of the spectral sensitivity of a sensitized material by exposing it to a spectrum of light through a graduated gray wedge. '''Wet collodion''' - a much improved calotype developed by Frederick Scott Archer. A sensitized glass plate was dipped into a bath of silver nitrate and exposed while still wet. The improved speed made much shorter exposures possible. '''Wet processing''' - processing by the application of chemicals in fluid form. The traditional method of photographic processing. '''Wetting agents''' - chemicals which, when used in minute quantities, reduce the surface tension of water. They are usually added to the final wash of films and plates to improve draining. '''White light spectrum''' - the electromagnetic wavelengths between 400-700 nanometers. Also referred to as the visible spectrum. '''Whole plate''' - a negative or print format measuring 6 * x 8 * inches. '''Wide-angle lens''' - a lens with wide covering power. It has a focal length which is less than the diagonal of the film format with which it is being used. '''Wood grain''' - a term for a pattern formed on a hologram by polarized. '''Wood print''' - a print made on a wood surface which has been photochemically prepared. '''Working aperture''' - the widest aperture at which an acceptable image can be achieved. '''Working solution''' - a liquid chemical that has been mixed and diluted for use. e858f830cbc8db77e9c8e62956094fb68ace65e0 0 594 1338 2006-03-23T04:01:48Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Xenon''' - a rare gas sometimes used with electronic flash tubes and enclosed arc light sources. '''Xerography''' - a photographic process which uses an electrically charged metal plate. On exposure to light the electrical charge is destroyed, leaving a latent image in which shadows are represented by charged areas. A powdered pigment dusted over the plate is attracted to the charged areas, producing a visible image. '''Xography''' - a system of photography which produces prints and transparencies with a three-dimensional effect. A cylindrically embossed lenticular screen is placed in contact with the film and a shutter behind the lens is arranged to scan the subject during exposure. '''X ray''' - electromagnetic radiations beyond ultraviolet which, when passed through a solid object and allowed to act upon a sensitive emulsion, form a shadow image of the internal structure of the object. '''X ray film''' - spectral sheet film for radiography, having a thick emulsion coated on both sides of the support to increase the absorption of X rays. 0184618011cfa25c041078dedd96336ab2911dec 0 595 1340 2006-03-23T04:02:18Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- 744390aabe168f30877c11535c648a5b6e16d923 0 598 1346 2006-03-23T04:02:46Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Zirconium lamp''' - an arc lamp used in powerful enlarges and projectors. '''Zoetrope''' - an early device for creating illusion of continuous motion. A sequence of still pictures was viewed so quickly through slits in a rotating drum, that the images appeared to merge. '''Zone focusing''' - a method of focusing the lens so that the depth of field extends over a preselected range of distances. '''Zone system''' - the method of determining exposure and development required for individual scenes, invented by Ansel Adams. It is based on analysis of subject luminosities in terms of ten gray tones, labeled zones 0 through X and previsualizing them as print densities. By measuring each subject luminance with a hand meter it is possible to determine how much the range of values must be contracted or expanded by negative development control to give the required values in the print. c39458c550c1f325a404637ef446171f7e2f6b1d 6 53 697 53 2006-03-23T15:41:32Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 345 719 2006-03-23T15:56:20Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 54 701 54 2006-03-24T04:05:59Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 55 703 55 2006-03-24T04:10:12Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 56 705 56 2006-03-24T04:11:37Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 251 349 2006-03-24T04:18:00Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Halation''' - diffused ring of light typically formed around small brilliant highlight areas in the subject. It is caused by light passing straight through the emulsion and being reflected back by the film base on the light sensitive layer. This records slightly out of register with the original image. *Halide *'''Hand coloring''' - process of applying color tints, in the form of paint, to a photographic image to create or enhance the color effect. *'''Hard gradation''' - term denoting the quality of harsh contrast in a photograph. *'''Hide''' - camouflaged barrier used by natural history and wildlife photographers. *'''High art photography''' - general term for an early form of artistic photography (1851-1870), in which photographers set out to match the style and subject matter of paintings of the period. *'''High key''' - photograph which contains large areas of light tones, with few middle tomes or shadows. *'''Highlights''' - the brightest ares of the subject, represented on a negative by dense deposits of black metallic silver, but reproducing as bright areas on the positive print. *'''Hill cloud lens''' - lens with a 180° angle of view, used for photographing cloud formations and other meteorological work. *'''Holding back''' - 1. Shortening the development time given to film to help reduce image contrast. 2. Method of decreasing exposure given to selective areas of the print. Also referred to as dodging. *'''Horizon''' - line at which earth and sky appear to meet. Its position, which can be altered by titling the camera or by cropping the image determines whether the sky or the landscape concentrates interest in the picture. A low horizon (tilting the camera up) concentrates interest in the sky while a high horizon (tilting the camera down) concentrates interest in the landscape. *'''Hydrobromic acid''' - acid liberated during the developing process by the reduction of bromide. *'''Hydrochloric acid''' - chemical used in some bleaching solutions. *'''Hydrogen peroxide''' - chemical used in hypo clearing agents. *'''Hydroquinone''' - reducing agent. It is used in developers to provide high contrast results in the presence of a strong alkali. *'''Hypo eliminator''' - chemical bath which removes traces of fixing agent from an emulsion. 7d136106547d30686a019bfbe5ac4a2565ed759f 0 406 963 2006-03-24T04:21:03Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Lamp black''' - pure carbon pigment, made from soot deposited from burning oils. *'''Laser''' - an achronym for Light Amplification by the Stimulated Emission of Radiation. It is a device that emits a light beam that has special qualities. Most lasers are a pure color and travel in a beam with out spreading. *'''Lead acetate''' - crystalline, highly poisonous powder used in some toning and intensifying solutions. *'''Latensification''' - method of increasing relative film speed by fogging after exposure and before development. It can be achieved by chemical or light means. *'''Lenticular screen''' - lens system consisting of a screen containing a number of small lenses.There are two applications of lenticular systems. They are used in some exposure meters to gather light and to determine the angle of acceptance of light by the meter. A lenticular screen consisting of a number of lenses et into rows can be used at the camera stage to produce stereoscopic images by synthesizing binocular vision. *'''Light trap''' - system of entry to a darkroom which allows easy access, but prevents unwanted light from entering. *'''Linked Ring Brotherhood''' - group of pictorialist photographers who broke away from the Photographic Society of Great Britain. Existed between 1892-1910. *'''Lippmann process''' - early color process invented by Professor Gabriel Lippmann (1845-1921). Light first passed through an almost transparent emulsion layer and was then reflected back by a layer of mercury. The interference between reflected and incident light produced a latent image in the emulsion which could be given b&w processing, but when backed with a mirror appeared in color. *'''Local control''' - method of controlling the final quality of a print by increasing or decreasing the exposure given to localized areas of the print by selective masking. e2d51e9a6d472abb23276e065b71bdb1d1cd1413 6 116 477 116 2006-03-24T07:44:36Z Wolfgang 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 164 175 2006-03-26T04:07:59Z Colin Kaminski 0 wikitext text/x-wiki Media Artist and innovator, since 1967, in the areas of film and video, avant-garde film, video art, holographic art, and more recently, stereoscopic 3D video, digital graphics - web media and web-based virtual reality. His films have received a number of awards, including a 1988 Los Angeles Film Critics Award, and his media art works are found in a number of international collections and have been exhibited internationally, including a 1997 stereoscopic 3D video showing at the Louvre, a 2002 film-video retrospective at the Electronic Media Arts Festival in Osnabruck, Germany, and a 2004 exhibition of 3D video, film, video at SeNef, Seoul, Korea. He also has an extensive background as a teacher in film production / film studies, is a past publisher of two periodicals on film and holography, and has invented / developed a number of film, video, holographic and 3D imaging techniques. In 2000-01 he was involved as Head of 2D/3D Graphics for the Mission Corporation (Bellevue, WA) in developments of speech-interactive (avatar-based) graphical interfaces for next-generation (post-PC) environments. He continues to create independent works in interactive 3D web graphics and installations. He has an extensive background as film and holographic arts producer, project lead and designer, critic, historian, writer, teacher and cultural activist, with special skills as cinematographer, videographer, holographic systems and installation designer, producer and director of films and videotapes, screen-writer, stereoscopic 3D videographer and editor, internet site designer, Speech-interactive Avatar UI designer and HTML and VRML programmer-creator. He is also a writer of screenplays, prose, and prose-poetry. d57cf989b83945ec045e7db776e1ed28e61daabd 6 115 475 115 2006-03-26T11:20:54Z Wolfgang 0 repl by file with smaller size wikitext text/x-wiki repl by file with smaller size 035686105a8efe8ca4548fd7e9b6185a9a3e25d9 6 32 587 32 2006-03-26T18:48:25Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 218 283 2006-03-26T18:53:39Z Colin Kaminski 0 wikitext text/x-wiki [http://www.integraf.com Integraf] Dr. Tung H. Jeong (better known as "T.J.") is a professor emeritus at Lake Forest College, Lake Forest, Illinois, and has over 35 years of experience in holography. He has led the field of holography as researcher, innovator, consultant, and, most significantly, educator. Having authored numerous articles, T.J. is recognized as a leading scholar in holography. TJ's recent publications include an article published in Applied Optics, the most widely read international holography journal. Besides research, T.J. has also produced two motion pictures. One entitled, "Introduction to Holography," was sponsored and marketed by Encyclopedia Britannica. A teacher at heart, T.J. has been invited to lecture and teach seminars at over 500 universities, professional societies, and industrial sites in Europe, China, Russia, among other international locations. T.J. has also co-chaired international conferences on holography and optics in Russia, Bulgaria, and Hungary. Moreover, for nearly 30 consecutive years, T.J. has hosted holography workshops for novices and experts. In 1982, T.J. started the triennial International Symposium on Display Holography. His most recent symposium attracted over 120 scientists, artists, and businessmen from 18 countries. Together with Dr. Hans Bjelkhagen, a visiting scientist from Sweden, T.J. discovered technology that makes true-color holograms possible. T.J. is also credited with the discovery of cylindrical holograms, changing holograms from flat formats into images people could walk around and view from all perspectives. In 1973, T.J. shared in the development of the technology that created three-dimensional moving holograms and was the first to implement the use of optic fibers, making holograms simpler and less costly to make. In the business world, T.J. serves as a worldwide consultant to corporations in various industries to develop holographic solutions. For example, T.J. has worked extensively with DuPont on their development of holographic photopolymers. With the development of this technology, holograms is becoming a common part of people's lives. (Photo: Encyclopaedia Britannica Educational Corp., 1972) T.J. joined the faculty of Lake Forest College in 1963 and served as director of the Center for Photonics Studies. He came to the U.S. from China as a young boy in 1948. Upon graduation from Amarillo High School in Texas, he attended Yale University under a full-scholarship, and received his B.S. degree in physics and mathematics in 1957. He completed his Ph.D. degree in nuclear physics at the University of Minnesota in 1963. A member of many professional societies, T.J. is a Fellow of the Optical Society of America and the recipient of the Robert Millikan Medal from the American Association of Physics Teachers. He is also recipient, of the Saxby Medal of the Royal Photographic Society of Great Britain and the Lifetime Achievement Award from the International Holographic Manufacturer's Association. T.J. has regularly chaired of the annual conference Practical Holography - Materials and Applications, sponsored by the International Society of Optical Engineering (SPIE) and the Society for Imaging Science and Technology (IS&T), taking place in San Jose, California. In November 2005, T.J. was a keynote speaker at the Holopack Holoprint international conference in Shenzhen, China. 97b7ea478b7f0878f6b1fdfbcc8be43f4ea6a0b0 0 496 1142 2006-03-26T18:56:38Z Colin Kaminski 0 wikitext text/x-wiki [http://www.mccormackholography.com/ Sharon's Website] Sharon McCormack was born in New York City and now lives and works in the Columbia River Gorge National Scenic Area, White Salmon, Washington. Since 1975, Sharon's professional activities have included Owner/ Director, School of Holography, San Francisco, CA to holographic lens system construction for X-ray applications to lecturing, consulting, and commissioned work in the field of holography. Over that period, Sharon has created numerous world-wide group & solo exhibitions, has won many prestigious awards & grants, and has been featured in a broad range of publications from technical journals to sport magazines. 40b8e36f158ef1844bb85c80f16a54396ebc55ec 0 167 181 2006-03-26T19:00:12Z Colin Kaminski 0 wikitext text/x-wiki [http://www.apepper.com/ Andrew's Web Site] Andrew Pepper studied Fine Art in the UK, where he began working with projected light and 3-D light installations. During this period he saw his first hologram in Paris, at an exhibition organised by Jody Burns and Posy Jackson, at the American Cultural Centre, in the City. He thought this would be the ideal medium to use to document his installations in 3-D. On conclusion of his Fine Art course, he spent 2 years at the Museum of Holography, in New York, as a Fulbright Scholar, and it was there that he learned how to make holograms at new York Holographic Labs. It was some time before he felt comfortable using the medium - wanting to find an alternative to the amazing 3-D effect which had originally attracted him to the medium. When he returned to the UK in 1981 he began lecturing and writing on creative holography and starting to produce his own work, which has now been exhibited in solo and group shows world-wide. He also completed a PhD in Fine Art Holography, the first of its type to be awarded by the Fine Art Department of the University of Reading. During 1988 Pepper was awarded a Lionel Robbins Memorial Scholarship which allowed him to continue his PhD research and carry out extensive exploration in a specially built holography studio at Reading University. In 1991 he moved to Cologne to take up a 5 year post with the newly established Academy of Media Arts, which as part of its studio activities was offering Holography under the direction of German Artist, Professor Dieter Jung. During this time in Germany he was able to realise a project he had been working on for several years earlier and founded the Creative Holography Index, The International Catalogue for Holography, which provided a very high quality collection of material about artists working in the medium, as well as commissioning several leading writers to give their views on the development of the field. While at the Academy he was introduced to the Internet and world wide web and eventually began to ‘translate’ the paper publication into a digital one, making it accessible to a much wider audience. He has remained interested in this idea of digital publishing and delivered several papers on the subject at international conferences. 1996 saw him move back to the UK to organise and chair Art in Holography2, a major international symposium which attracted speakers and delegates from all over the world and concentrated entirely on the art of the medium. From 1999 - 2004 he was director of the Shearwater Foundation Holography program, established by Posy Jackson in 1987. Each year it provided 100,000 US Dollars to support and encourage creative holography, as well as honouring several artists with the annual Holography Award, given to outstanding practitioners in recognition of their major contribution to the field. Pepper is a visiting lecturer at the Nottingham Trent University, School of Art and Design, a81150217a4ebfab9398686a109b60c4c291408e 0 165 177 2006-03-26T19:15:51Z Colin Kaminski 0 wikitext text/x-wiki [[Image:AStephens.jpg]] [http://anait.com/ Anait's Web Site] Anait (Anait Arutunoff Stephens) was born in Berlin, Germany in 1922. On August 21, 1998, Anaït lost her battle against cancer in Santa Barbara, California, USA, in 1998. 1954 Instituto Nacional de Bellas Artes, Mexico, with Orozco Romero. 1958 Mexico City College, Mexico, with Toby Joysmith. 1964 University of California at Los Angeles, USA, with Dewain Valentine. 1971 School of Holography, San Francisco, California, USA, with Lloyd Cross. 1980 Museum of Holography, New York, USA, Artist-in-Residence. Professional Activities Lectures (selected) 1974 Studio lectures, Artist’s studio, Los Angeles, California, USA. 1977 Electro-Optics Seminar, Anaheim Convention Center, Anaheim, California, USA. 1978 Third Conference On Holography, USSR (the only woman and artist in attendance). Museum of Holography, New York, USA. 1980 Santa Barbara Museum of Art, Santa Barbara, California, USA. 1983 Studio lectures, Artist’s studio, New York, USA. 1986 The Royal Photographic Society Holography Group, London, UK. 1990 Chicago Art Institute, Chicago, Illinois, USA. 1991 Durand Art Institute, Lake Forest, Illinois, USA. 1992 Visiting tutor, Royal College of Art, London, UK. PUBLICATIONS Catalogues (selected) 1976 Through the Looking Glass, Museum of Holography, New York, USA. 1977 Theme and Variation, National Academy of Science, Association of Science – Technology Center, Washington, DC, USA. 1978 Alice in the Light World, Isetani Museum, Tokyo, Japan. 1979 ANAIT Retrospective 1966-1979, Museum Of Holography, New York, USA. 1983 Light Dimensions, Octagon, Bath, UK. 1984 Licht-Blicke, Deutsches Filmmuseum, Frankfurt/Main, Germany. 1987 Light Dreams, Kalamazoo Art Institute, Michigan, USA. 1991 Fiat Lux! Holografia, Asturias, Spain. 1991 Fourth International Exhibiton of Display Holography, Durand Art Institute, Lake Forest, Illinois, USA. Articles/interviews 1973 Blasco-Ibanez, “Down to the Sea in Sculpture”, Los Angeles Herald-Examiner Sunday Magazine, California Living. 1974 Melinda Wortz, “Los Angeles: Anait at Gallery 707”, Arts Magazine. 1978 Lincoln F. Johnson, “Defining, Evaluating Holography”, The Baltimore Sun. Anait, “My Art in the Domain of Reflection Holography” Leonardo Journal, Vol. 11 pp. 306-7. “A Letter to Leonardo”, Leonardo Journal, Vol. 11, pp. 351. 1979 William Wilson, Review, A-B Gallery, Los Angeles Times. 1980 James Wood, “Painterly Holography”, Artweek. 1981 Ricky Horton, “Anait: Holography as Art”, New York Arts Journal. 1987 Joan Crowder, Santa Barbara, News Press. OTHER INFORMATION 1972 Opened “Gallery 707”, Los Angeles. First gallery for women artists in LA. 1976 First solo art exhibit in the world in reflection holography: “Theme and Variation”. 1986 Listed in “Allgemeines Künstlerlexikon” (International Art Encyclopedia). 4b21ee688fe70223afe5dcd06cf39b0da24bfc6a 6 107 419 107 2006-03-26T19:16:53Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 170 187 2006-03-26T19:24:26Z Colin Kaminski 0 wikitext text/x-wiki [[http://www.anamarianicholson.com/ Anna's Web Site]] f6bd52d29c8f2d410b070d90cd8b8218163113b6 0 284 415 2006-03-26T19:26:09Z Colin Kaminski 0 wikitext text/x-wiki [[http://www.hololab.com/ Ikuo's Web Site]] 200725896d40d33e07643c6a48fa314af6f00dc5 0 217 281 2006-03-26T19:33:05Z Colin Kaminski 0 wikitext text/x-wiki [http://www.vilamedia.com/ VilaMedia's Web Site] 6d589f6d169cc09c6f5b9b6de0975f261ebfecb1 6 122 497 122 2006-03-26T22:20:46Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 209 265 2006-03-26T22:22:54Z Colin Kaminski 0 wikitext text/x-wiki [[Image:DBattin.jpg]] [http://www.geocities.com/greenpagoda/islandholo1.html Dave's Web Site] IT all started for me in the Museum of Holography, in the late 70s. after making one visit i was hooked for life! Seeing what could be done was unbeleivable..... I then joined as a member and started to read any information i could absorb. Attending college in Boston I found all kinds of new info at the college libaries. Upon graduation from college I headded west, finding work near Los Angles in a large machine shop, I found this very convenient for making tooling for my holographic components. After leaving LA and returning to New York, I continued my holographic studies, and met a fellow holographer, Mark Segal (owner of now defunct Spatial Images International)at this lab we produced a large ammout of DCG holography. A short time later a head hunter contacted me about a job working for company called Farirchild Weston Space and Camera, the job was for an optical engineer, I couldn't wait for the interview! They hired me in a flash! The optics lab was about 2500 sq.ft of total OPTICS! Lenses, mirrors, lasers a gigantic isolation table (20 tons+), I spent the next five years building telephoto lenses ths size of 55 gallon drums and tiny ccd cameras that would fit in matchbox! This is where I really learned about the nature of light and optics. 79317af696e9bf934471b16ba84e245512b76295 6 138 531 138 2006-03-26T22:31:04Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 237 321 2006-03-26T22:33:18Z Colin Kaminski 0 wikitext text/x-wiki [[Image:FDeFreitas.jpg]] [http://www.holoworld.com HoloWorld] Frank started holography in 1983. While having no formal training in science, he has made a career in science and technology. He runs [http://www.holoworld.com HoloWorld], perhaps the most popular web site for holography. He is one of the pioneers of using laser pointers to make holograms. He is the author of "Shoebox Holography" and runs an internet radio program, [http://www.holoworld.com/holotalk/index.html HoloTalk]. He also teaches holography to childeren in workshops. cdaeaf38969ea9ea2ae896c104066cec2660ad32 0 395 941 2006-03-26T22:52:16Z Colin Kaminski 0 wikitext text/x-wiki [[Image:JBlyth.jpg]] a129eecfa2418870c4dc76082d5783d2808450ed 6 35 665 35 2006-03-26T22:52:44Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 42 679 42 2006-03-26T23:22:42Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 404 959 2006-03-26T23:23:08Z Colin Kaminski 0 wikitext text/x-wiki [[Image:KBazargan.jpg]] Optics has interested me ever since I was a small child. Everything from how a movie was projected in a cinema, to why shadows were sometimes sharp and sometimes not, constantly occupied my mind. This inquisitiveness finally led to a masters degree in Optics, at Imperial College, London. Here I developed an interest in holography, so I stayed on to complete a PhD in Display Holography. I have uploaded the thesis [http://www.focalimage.com/public/kaveh-PhD.pdf here]. The two areas I worked on most were natural color holography, and dispersion compensation. For colour holography I proposed using the three "prime" colors (as first identified by W A Thornton in 1971) for image recording. The work on dispersion compensation led to a compact hologram viewer which was patented, and is now marketed as the [http://www.apple.com/science/profiles/voxel/ "VoxBox"]. After 5 years of research in holography I was distracted by the fascinating emergence of "desktop publishing", and set up a graphics and typesetting [http://www.river-valley.com company] in 1988, which is now established and pays the bills. I am now raising my head again in holography and hope to continue where I left off. [http://www.holographer.org The Holographer] represents my re-entry into the field. 28734756aa7636407946e6d306646253d4cc12ec 6 41 675 41 2006-03-26T23:37:55Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 400 951 2006-03-26T23:38:42Z Colin Kaminski 0 wikitext text/x-wiki [[Image:JUpatnieks.jpg]] Director of Applied Optics Ann Arbor, Michagan Professor, Electrical and Computer Engineering Department University of Michigan Mechanical Engineering and Applied Mechanics Department University of Michigan Born: May 7, 1936, Riga, Latvia ---- ==List of Patents== *3,506,327 Wavefront Reconstruction Using a Coherent Reference Beam, 1970 *3,532,407 Spatial Frequency Reduction in Holography, 1970 *3,539,241 Method of Imaging Transparent Objects with Coherent Light, 1970 *3,545,835 Two-Beam Holography with Reduced Source Coherence Requirements, 1970 *3,548,643 Holographic Vibration Analysis Method and Apparatus, 1970 *3,580,655 Wavefront Reconstruction", 1971 *3,637,313 Method of Imaging Transparent Objects with Coherent Light, 1972 *3,677,617 Technique of Holographic Data Reduction Utilizing an Additional Diffusing Structure During Reconstruction, 1972 *3,748,048 Method of Detecting Changes in Specular Surface, 1973 *3,838,903 Wavefront Reconstruction, 1974 *3,894,787 Holograms, 1975 *4,012,150 Holographic Light Line Sight, 1977 *4,057,317 Hologram Projector, 1977 *4,223,975 Aberration Correction of Magnified Holographic Images, 1980 *4,277,137 Coherent Optical Correlator, 1981 *4,643,515 Method and Apparatus for Recording and Displaying Edge- Illuminated Holograms, 1987 *4,711,512 Compact Head-Up Display, 1987 *5,151,800 Compact Hologram Displays and Methods of Making Compact Hologram, 1992 *5,483,362 Compact Holographic Sight, 1996 6d18e713af1529cd397829690649fa163d236a5a 6 94 819 94 2006-03-26T23:57:31Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 481 1112 2006-03-26T23:58:11Z Colin Kaminski 0 wikitext text/x-wiki [[Image:RLakes.jpg]] [[http://silver.neep.wisc.edu/~lakes/ Rod's Website]] *Columbia University, Mathematics, 1964, 1965 *Rensselaer Polytechnic Institute, B.S., 1969; Ph.D., 1975 *Yale University, Research Associate, 1975 -1977 Applications of holography: experimental mechanics Lakes, R. S., Gorman, D., and Bonfield, W., "Holographic screening method for microelastic solids", J. Materials Science, 20 2882-2888 (1985). Classical elastic and Cosserat elastic materials may be quickly distinguished via holographic study of displacement of a notch at the corner of a square section bar in torsion. Chen, C. P. and Lakes, R. S., "Holographic study of conventional and negative Poisson's ratio metallic foams: elasticity, yield, and micro-deformation", J. Materials Science, 26, 5397-5402 (1991). This article presents an experimental study by holographic interferometry of the following material properties of conventional and negative Poisson's ratio copper foams: Young's moduli, Poisson's ratios, yield strengths, and characteristic lengths associated with inhomogeneous deformation. The Young's modulus and yield strength of the conventional copper foam were comparable to those predicted by microstructural modelling on the basis of cellular rib bending. The re-entrant copper foam exhibited a negative Poisson's ratio as indicated by the elliptic contour fringes on the specimen surface in the bending tests. Inhomogeneous, non-affine deformation was observed holographically in both foam materials. Download pdf Lakes, R. S. and Elms, K., "Indentability of conventional and negative Poisson's ratio foams", J. Composite Materials, 27,1193-1202, (1993). The indentation resistance of foams, both of conventional structure and of a novel re-entrant structure giving rise to negative Poisson's ratio, was studied using holographic interferometry. In holographic indentation tests, re-entrant foams had higher yield strengths sigma y and lower stiffness E than conventional foams of the same original relative density. Damage in both kinds of foam occurred primarily directly under the indenter. Calculated energy absorption for dynamic impact is considerably higher for re-entrant foam than conventional foam. Chen, C. P. and Lakes, R. S., "Holographic study of non-affine deformation in copper foam with a negative Poisson's ratio -0.8", Scripta Metall et Mater., 29, 395-399, (1993). Negative Poisson's ratio copper foam (Poisson's ratio -0.8) with a permanent volumetric compression ratio of 2.2 exhibits a greater non-affine (inhomogeneous) deformation than either conventional foam or negative Poisson's ratio foam (Poisson's ratio = -0.1) with a volumetric compression ratio of 3. Anderson, W. B., Lakes, R. S., and Smith, M. C., "Holographic evaluation of warp in the torsion of a bar of cellular solid", Cellular Polymers, 14, 1-13, (1995). Holographic methods are utilized to examine deviations from classical elasticity in a cellular solid, polymethacrylamide closed cell foam. A square cross section bar is subjected to static torsional deformation. The warp deformation is observed to be less in a foam bar than in a homogeneous polymeric bar used as a control. The homogeneous bar obeys the predictions of classical elasticity. Behavior of the foam bar is consistent with Cosserat elasticity. In a Cosserat solid, points in the continuum to rotate as well as translate, and the material supports couple per unit area as well as force per unit area. Cosserat effects can lead to enhanced toughness. This image shows holographic fringes associated with warp. Development of holographic methods Lakes, R. S., "Multi wavelength techniques in holographic interferometry", Journal of Modern Optics, 35(9), 1459-1465 (1988). Techniques are presented which take advantage of the wavelength dependence of various phenomena in holographic interferometry. Image-plane interferograms illuminated with light containing multiple wavelengths exhibit color dispersion of the fringes. We extract from this dispersion, full- field information concerning displacement components which are not disclosed by monochromatic illumination. Cohen, B. and Lakes, R. S., "Aberration reduction in one step lens image plane holography", Applied Optics, 27, 3322-3323 (1988). A simple correction scheme is presented, which permits the use of large aperture lens systems of modest quality, even single element lenses, to produce image plane holograms viewable in white light. The present method allows white light reconstruction and corrects field curvature, which is the most objectionable aberration in display holograms. The field curvature was corrected by making the hologram with diverging light and illuminating the hologram with collimated light to introduce a compensating negative curvature of field. Wuest, D. and Lakes, R. S., "Color control in reflection holograms by humidity", Applied Optics, 30, 2363-2367 (1991). A method is presented which permits control of the reconstruction wavelength of reflection holograms and holographic optical elements [HOE's]. This approach makes use of developer and bleach which minimize emulsion shrinkage combined with control of ambient humidity to control the emulsion shrinkage during formation and reconstruction. A simple index matching approach to the elimination of the wood grain effect in reflection holograms is also presented. Applications: Holographic Optical Elements Wadle, S. and Lakes, R. S., "Holographic diffusers: polarization effects", Optical Engineering, 33, 1084-1088, (1994). In some applications of diffusers, it is desirable to minimize the diffuse back reflection of light. Use of polarized light is one way to reduce this back reflection. To that end, the effect of diffusers upon polarized light is studied experimentally. Diffusers based on ground glass, white plastic containing scatterers, and holographic optical elements are considered. The ground glass and HOE diffusers preserve polarization in the diffusion process, but the white plastic does not. Diffuse back reflection from ground glass or holographic diffusers can be significantly reduced by the use of an isolator based on a quarter wave plate. Wadle, S., Wuest, D., Cantalupo, J., and Lakes, R. S., "Holographic diffusers", Optical Engineering, 33, 213-218, (1994). Holographic diffusers were prepared using silver halide (Agfa 8E75 and Kodak 649F) and photopolymer (Polaroid DMP128 and DuPont 600, 705, and 150 series) media. It was possible to control the diffusion angle in three ways: by selection of the properties of the source diffuser, by control of its subtended angle, and by selection of the holographic medium. Several conventional diffusers based on refraction or scattering of light were examined for comparison. Wuest, D. and Lakes, R. S., "Holographic optical element for projection of stereo images", Applied Optics, 31, 1008-1009 (1992). We present a holographic element capable of projecting dynamic stereo images, and allowing the observer to see through the device, for possible use as a head up display in aircraft. The device is based on a volume reflection holographic optical element which contains two sets of Bragg planes. Each set of Bragg planes diffracts light from a two-dimensional source to the appropriate eye to achieve a stereo effect. Lakes, R. S. and Vick, G., "Partial collimation of light from a diffusely reflective source", J. Modern Optics, 39, 2113- 2119, (1992). A general purpose collimator capable of collimation of radiation from an arbitrary thermal source of diffuse light is incompatible with the second law of thermodynamics. However there are 'special purpose' collimators which would not be generally applicable. A new collimator which is effective when placed close to a white (diffusely reflective) source is presented. Wadle, S. and Lakes, R. S., "Holographic diffusers with low back-scatter", J. Modern Optics, 42, 1387-1396, (1995). Holographic diffusers have been produced with very low back diffusion in comparison with diffusion in the forward direction. Reduced back diffusion was achieved by lamination and index matching procedures which minimized the formation of Bragg planes parallel to the film surface. Photopolymer media were used as phase media. Diffusers with the lowest values of back diffusion were prepared by moderately restricting the field angle of incident light during formation. 9a8ab2dc30f42f98e478de8102593954aa0be29d 0 468 1086 2006-03-28T00:28:36Z Colin Kaminski 0 wikitext text/x-wiki Pre-swelling is used to make the replay color of a reflection hologram shorter. It works by expanding the gelatin before exposure and allowing the gelatin to shrink after exposure therefore making the fringe spacing closer. [[TEA]] The most common method for pre-swelling. efa0b9c6f3f70374a4d404443fa54f8c4801b795 0 575 1300 2006-03-28T00:33:51Z Colin Kaminski 0 wikitext text/x-wiki '''by Ed Wesly''' The replay color of a reflection hologram depends not only on the color of the laser recording the hologram, but also on the way the hologram is processed. For bleached holograms on silver halide plates, the processing will either recreate the laser color, (develop-rehalogenating bleach for no emulsion shrinkage), or the hologram will reconstruct at colors shorter than the laser's wavelength due to shrinkage of the coating through loss of material either through removal of silver halides in fixing or by loss of developed silver in a silver solvent bleach. Overall control of image color is afforded by the latter two methods, as the shrinkage of the coating is proportional to the amount of developed silver and the color can be controlled by juggling of exposure and development times. However the range of hues is limited, with only oranges and greens possible with a helium neon laser using these schemes. If the hologram is exposed to first one and then another of two different objects, both objects will be the same color, unless some clever masking scheme is used. But the artist needs to make holograms with different colored images in it but usually they can only afford one color of laser (if that). In the original triethanolamine duo color paper in holosphere[1], Jeff Blythe explained how he recorded two different colored images in the same hologram using only a helium neon laser. The trick was to record the two separate interference systems in the emulsion while varying the thickness of the coating between the two exposures. WHY IT WORKS: An ideal reflection hologram recording would have layers of varying refractive index to represent the bright and dark fringes present during. Their thickness would be 1/4 of the recording laser's wavelength, so that the exact same wavelength of recording out of all of those present in the white light fits in them snugly and is strongly reflected thanks to Bragg diffraction. If the material in the holographic recording layer were to shrink, a shorter wavelength than the original one would fit into the fringe structure and the color of reconstruction would be greener or even bluer. Blyth's ingenuity lies in pre-swelling the emulsion before exposure to make it thicker. After exposure and processing, which removes the plumping agent, the emulsion shrinks back to its original out of the box thickness. The fringe system also shrinks, inversely proportional to the swelled state during exposure. A higher concentration of plumping agent in the pre-soak will expand the gelatin coating more, so the eventual collapse of the fringe spacing will be more dramatic and bluer. TEA (TriEthanolAmine) is a water soluble oil, but it does not evaporate like water. A holographic plate soaked in a 10% solution of TEA in water will swell up three to ten times its original thickness while wet, but when the water dries out of the gelatinous sponge, the ten per cent of oily TEA is left behind, now swelling the emulsion to about 10% thicker than at first. The plate is now exposed to 633 nm He-Ne light for a single beam reflection hologram. The TEA is washed out. The hologram is processed and dried so that it is the out of the box thickness, which is 10% less than when it had been exposed. The holographic pattern is now 10% thinner too, and it reflects a color about 10% shorter in wavelength, about 570 nm, a yellowish green. MAKING A TRIETHANLOAMINE PALETTE: Lay out bottles of different concentrations of TEA; usually a series of 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0 per cent solutions will span the visible and maybe even into the ultraviolet in some cases with a sensible division of the spectrum. Soak a plate or two in each concentration for two to five minutes, the soaking time is not as critical as the time spent exposed to your "safe"light. The truly critical step in triethanolamining is the elimination of streaking. The viscous TEA flows at a different rate than water if the plate is held vertically, and dries in messy streaks over the plate. The original practitioners, Lon Moore and John Kaufmann, used windshield wiper blades to squeegee most of the syrup out of the emulsion, eliminating streaks and quickening drying times. However this technique requires a knack which needs to be mastered, applying even pressure from edge to edge during the wipe and being able to do it consistently from plate to plate otherwise your calibration palette is worthless. I have heard that Edwina Orr of Richmond Holographic Studios uses an air knife which blows a concentrated stream of air across the plate as it is conveyed below it on a sliding drawer type arrangement to standardize production. Greg Cherry and Nancy Gorglione have described[2] their spin coating apparatus, and thanks to a donation to the Holography Dep't @ SAIC by Weston Morris of his Swirl Art machine we have our own. This is the most fun way of TEAing, plus it is consistent, no streaks, and the plate is dry enough to shoot most assuredly after 5 minutes on the machine, but usually two minutes suffices for the lower concentrations in most cases. After a plate is soaked and dried for each concentration, they should be exposed for one half the normal exposure they would get for processing in CWC2 and copper sulfate bleach (or your favorite rehalogenator). The pre-soak in water dissolves out the excess bromine put in during manufacture to extend the shelf life of the plates, so there is an increase in sensitivity of about one stop. Before processing, rinse the plates in water to remove the TEA so that it won't pollute the developer. The CWC2 developer followed by a rehalogenating bleach type of processing is chosen for its non-shrinking virtue. After gentle air drying, the different concentrations can be sorted by their replay colors. QUESTION? What has happened to the reference angle? FOR DUO COLOR HOLOGRAMS: Usually the practice is to pre-soak for the highest concentration you want to use. Wash the plate after the first color's exposure, soak in the second color's TEA bath, or plain Kodak Photo-Flo if the second color is to be laser red. You could start with both exposures being equal between the two at first, but may have to tweak one or the other up or down for color blending. REFERENCES -------------------------------------------------------------------------------- [1]. Jeff Blyth, Pseudoscopic Moldmaking Handy Trick for Denisyuk Holographers, holosphere Vol 8, #3. [2]. Greg Cherry, Spin Coater for Triethanolamine Pretreatment, L.A.S.E.R. News, vol 5, #2, 1989 0e2148fc80d28200835f5c84eee133e8002c77b9 0 519 1188 2006-03-28T00:34:40Z Colin Kaminski 0 wikitext text/x-wiki [[Triethanolimining| Triethanolimining by Ed Wesly]] 50e4e88759deb1e7e8d36d1db812fc4e90d7bab0 0 222 291 2006-03-28T00:44:19Z Colin Kaminski 0 Edward Wesley moved to Edward Wesly wikitext text/x-wiki [[Image:Edwesley.jpg]] Ed Wesly Ruby Pulsed Hologram - Fermilab PROFESSIONAL OBJECTIVE: To continue to share my wealth of knowledge and experience with more students in the fields of lasers, optics, holography and photography. TEACHING EXPERIENCE: Full-Time Faculty, Harrington College of Design, teaching Physics of Light (Optics), Photo-History, and College Math in the Digital Photography Department, January 2005 to present. Adjunct Assistant Professor, teaching a variety of classes in the Art and Technology and Liberal Arts Departments at the School of the Art Institute of Chicago, including the Beginning and Intermediate/Advanced Holography Studio, Optics for Artists, 3-D Hard Copy, and The Physics of Everyday Objects, January 1986 to present, with a couple of hiatuses. Instructor, Columbia College, Chicago, for the courses, "The Physics of Lasers, Holograms, and Modern Optics", "Photographic Theory/Laboratory Practice for Cinematographers", and "Imaging Optics", February 1985 to June 1997. Teacher, Cicero School, Cicero, IL, 7th and 8th grade Math Classes, September 1981 to June 1982. Director of Education for the Fine Arts Research and Holographic Center, Chicago, IL, June 1980 to May 1981. Teacher, Hardey Preparatory School, Chicago, 6th, 7th, and 8th grade Math Classes, September 1977 to June 1980. TECHNICAL EXPERIENCE: Production Holographer, CFC International, Countryside, IL, laboratory technician preparing holographic images for mass production, October 1998 to November 2004. Sales Engineer, BEA electro-optics, Des Plaines, IL, manufacturer's representative for a variety of electro-optical companies, June 1997 to October 1998. Research Associate at Lake Forest College, Lake Forest, IL, supported by a grant from a manufacturer of medical equipment to test the feasibility of replacing conventional optics in some of their equipment with Holographic Optical Elements, October 1987 to February 1993. Holographic Engineer for Northwestern University, Evanston, IL, researching holographic endoscopes using Ruby laser light piped through fiber optics, May 1986 to May 1987. Holographic Engineer for Holicon Corporation, Evanston, IL, setting up a studio to record holographic portraits using a Ruby laser, May 1986 to May 1987. Holographer for the 15 foot Bubble Chamber at Fermilab, Batavia, IL. Part of a team using a Ruby laser to make holograms of atomic particle tracks, March 1985 to April 1986. Optical Engineer for Magnaflux Corporation, Chicago, IL. Designed and built an 8 by 8 foot isolation table equipped with an Argon laser for real time interferometry of large objects, October 1983 to September 1984. EDUCATIONAL BACKGROUND: University of Illinois at Urbana, Bachelor's of Science Degree in the Teaching of Mathematics, January 1976. PROFESSIONAL ORGANIZATIONS: Member of the Optical Society of America, (OSA), and the Society of Photo-Instrumentation Engineers (SPIE). Councillor for Chicago Chapter of SPIE/Optical Society of Chicago Featured Speaker at the June, 1997 meeting of the Optical Society of Chicago. PUBLICATIONS TEXTBOOKS (self-published): INSTRUCTION MANUAL FOR THE HOLOGRAPHY STUDIO AT SAIC, September 1995 OPTICS FOR ARTISTS, September 1995 (e-version on-line Fall 2003) PHOTOGRAPHIC THEORY/LABORATORY PRACTICE For Cinematographers, September 1995 IMAGING OPTICS, February 1996 VIDEOS: "Ruby Laser Guts", 1996, and "Gaseous Lasers", 1996 SELECTED ARTICLES: "Inside-Out Engineering: Characterizing the Holographic Stereogram Printer at The School of the Art Institute of Chicago", Proceedings of the SPIE, 1997. "A Toast to Nick Phillips", Leonardo, Volume X, Number 3, 1992. "A Proposal for a National Space Monument", Proceedings of the SPIE, Vol. 1600, 1991. "Holography of Particle Tracks in the Fermilab 15-Foot Bubble Chamber," with W. Smart et al., Nuclear Instruments and Methods in Physics Research A297, 1990, p.364-389. "Teaching Holography in an Art School Environment," Proceedings of the SPIE, Vol. 1396, 1990. "Progress in True Color Holography", with T. Jeong, Proceedings of the SPIE, Vol. 1211, 1990. "Recycling Holographic Plates", Proceedings of the Third International Symposium on Display Holography, Lake Forest College, 1988. "Exploring Personal Holography", Darkroom and Creative Camera Techniques, Nov/Dec. 1986. "Seven Single Beam Projects", Proceedings of the Second International Symposium on Display Holography, Lake Forest College, 1985. Technical Editor for holosphere, the Advocate of Holographic Art, Science, and Technology, 1985 to 1991. REFERENCES: Dr. Tung Jeong, emeritus, Lake Forest College, Lake Forest, IL (Tjeong@aol.com) Dr. Hans Bjelkhagen, DeMontfort University, Leicester, England (Hansholo@aol.com) Dr. Manfred Stelter, PTI, Oak Creek, WI (pti@execpc.com) Dr. Gerald Cohn, Cyber-Tech, Evanston, IL (cybertek@megsinet.net) Dr. Elizabeth Wright, School of the Art Institute of Chicago, Chicago, IL (ewright@artic.edu) Dr. Pan Papacosta, Columbia College, Chicago, IL EXHIBITIONS: GROUP SHOWS Untitled, Richard Hunt Art Center, Benton Harbor Michigan, November 1996. Candy for the Eyes, Mind and Sol Gallery, Chicago, IL, September 1995. Unknown Chicago, Gallery 312, Chicago, IL, July 1995. The Fourth International Exhibition of Display Holography, Lake Forest College, July 1991. Matter Over Mind Sculpture Conference, Fermilab, Batavia, IL, May 1991. Diorama Wonderama, Gallery 836, Chicago, IL, November 1990. L.A.S.E.R. Members Show, Holos Gallery, San Francisco, CA, Summer 1990. New Media, New Directions, Northern Indiana Arts Association, Munster, IN, August, 1990. International Congress on Art in Holography, May - July 1990. The One-Liner Show, Gallery F-XU, Chicago, IL, February 1990. Visual Perceptions: Color, Light and Space, Gallery of Design of the Merchandise Mart, Chicago, IL, February 1989. The Third International Exhibition of Display Holography, Lake Forest College, July 1988. Visions in Light, Museum of Holography, Summer 1988. Images in Time and Space, Montreal, Canada, May 1987 to June 1989. The Holographic Instant: Pulse Laser Holograms, at the Museum of Holography, New York, May to October 1987. A.I.R. Waves at the Museum of Holography, New York, January to May 1987. 2 X 2 Show at the School of the Art Institute of Chicago, May 1986. Holography Group Show at the Limelight, Chicago, February 1986. Holography Exhibition at the School of the Art Institute of Chicago, November 1985. The Second International Exhibition of Display Holography, Lake Forest College, July 1985. New Light, Chicago Public Library Cultural Center, July 1984. The Connie Show, W.P.A. Gallery, Chicago, IL, April 1984. Stare Magazine Fifth Anniversary Show, at Word City, Chicago, June 1982. Post-Mortem Moderne, at the House o' Beauty, Chicago, IL, July 1980. First Contact, Chicago, IL, February, 1979. Illinois Photographers' Lottery, De Kalb, IL, May, 1978. EXHIBITIONS: ONE MAN SHOWS Down in the Basement, Artigliography, Indianapolis, IN, September - October, 1990. Doodles, Atlanta Gallery of Holography, Atlanta, GA, April 1990 Recent Pulsed Stuff and Other Delights at Benny's CASINO, Chicago IL, August 1986. AWARDS: Artist in Residence Direct Grant, from the Museum of Holography, New York, October 1984. Participant in the International Congress on Art in Holography, St. Mary's College, South Bend, IN, July 1990. COLLECTIONS: Global Images, Vancouver, British Columbia, Canada. Museum of Holography Collection, MIT Museum, Cambridge, MS. Dimensional Imaging Consultants, Niles, MI. Hans Bjelkhagen, Leicester, England 0c1e24f97d4b1a7f71c759f8f0b647ef523acaf8 0 250 347 2006-03-29T15:40:14Z Colin Kaminski 0 wikitext text/x-wiki [[Image:GFavalora.jpg]] Gregg E. Favalora (Arlington, Mass., USA) *B.S., Yale Univ. (1996) *S.M., Harvard Univ. (1998) *Founder and CTO, Actuality Systems (1997-present) *[http://www.actuality-systems.com Actuality Systems, Inc.] *[http://www.greggandjenny.com/gregg Personal homepage] Gregg Favalora is not a holographer in the traditional sense. Rather, he has focused on the design and development of many three-dimensional display architectures since being bitten by the "3-D bug" in 1988. He holds a BSEE from Yale and a Masters' in Engineering Sciences from Harvard, which he left in 1997 to found Actuality Systems, a firm specializing in 3-D visualization for medical imaging, oil & gas, and entertainment. His research interests include optics, 3-D displays and electro-holography, biologically-inspired electronic systems design and "neuromorphic engineering", and industrial design. In his spare time he wishes he were better at playing the drums and the ancient strategy game of go. In 1996, while a student at Yale, Gregg developed the first parallel raster-scanned 3-D display under the guidance of Prof. Peter Kindlmann. It used 32 laser diodes in conjunction with a polygonal mirror scanner to illuminate a rotating diffuse screen with 32,768 voxels. The autostereoscopic, full-parallax volumetric image occupied roughly egg-sized volume. It is described in U.S. Pat. 5,936,767 and has been in operation - through at least 2006 - in Becton Center at Yale University since 1996. In 1997, Gregg founded Actuality Systems to develop software and opto-electronic systems for true 3-D visualization. In 2001, Actuality's engineers developed the world's highest-resolution volumetric 3-D display. Now marketed under the name Perspecta(r), it generates 10"-diameter 3-D imagery by projecting patterned light at 6,000 frame/s onto a swiftly rotating diffuse screen. The imagery created by Perspecta is composed of approximately 100 million voxels. Through 2006, Actuality's innovations include: "Spatial Visualization Environment," the world's first software platform that interprets graphical data from standard applications and processes them for displays of a wide variety of underlying physics, such as multiplanar displays, holographic displays, and highly-multiview displays. With a team including Oliver S. Cossairt, Rick K. Dorval, and Sam Hill, showed that it is possible to create a volumetric display with voxels having viewer-position-dependent effects, such as variable opacity. Developed several quasi-holographic "aerial" display systems that project free-floating imagery measuring 1" x 1" x 1" to 6" x 6" x 3". Working with leading hospitals to use volumetric 3-D displays for the review of cancer therapy plans using radiation oncology. Gregg is an inventor or co-inventor on: *U.S. Pat. 5,936,767, "Multiplanar autostereoscopic imaging system" *U.S. Pat. 6,183,088, "Three-dimensional display system" *U.S. Pat. 6,487,020, "Volumetric three-dimensional display architecture" *U.S. Pat. 6,512,498, "Volumetric stroboscopic display" *U.S. Pat. 6,570,681, "System and method for dynamic optical switching" *U.S. Pat. 6,940,653, "Radiation conditioning system" Gregg is a winner of the 1996 National Inventors' Hall of Fame / BFGoodrich Collegiate Inventors Award, is a member of the MIT Technology Review "TR-100" young innovators, and is a frequent speaker on the topic of entrepreneurship. Due in large part to the efforts of Actuality's engineers, his work has appeared in the Wall Street Journal, Wired, CNN Headline News, and a variety of major technology and medical publications around the world. 3c0bf31a507e99d41d9ea79633321e538a3af96e 6 148 561 148 2006-03-29T15:40:47Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 523 1196 2006-03-30T01:20:24Z Colin Kaminski 0 Talk:Advanced Mathematics for Holography moved to Talk:Holography Transmission Equations: Need more room! wikitext text/x-wiki #redirect [[Talk:Holography Transmission Equations]] 826f9d5598eb8b1624a085200073cce898cd886c 0 278 403 2006-03-30T01:41:55Z Colin Kaminski 0 Holography Transmission Equations moved to Holography Transmission Equations Part I: Better title. wikitext text/x-wiki #redirect [[Holography Transmission Equations Part I]] d156f21ca0aaf755fb350e2a7da17a174ed75f5d 0 279 405 2006-03-30T01:41:55Z Colin Kaminski 0 Holography Transmission Equations moved to Holography Transmission Equations Part I wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== [[Image:InterferenceEQ.gif]] Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: [[Image:SpatialEQ.gif]] (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say. (while I nodded off!) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html [[Image:DiffractionEQ.gif]] They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) [[Image:EdExample1.gif]] Just like it should. If we repeat the above but with m = 2, we get: [[Image:EdExample2.gif]] Unh-unh! sin of an angle can’t be >1! (This is called a [[http://en.wikipedia.org/wiki/Evanescent_wave evanescent]] wave and is not propegated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) [[Image:EdExample3.gif]] (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: [[Image:EdExample4.gif]] Replacing m by 2, [[Image:EdExample5.gif]] When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm [[Image:EdExample6.gif]] Replacing m by 2, [[Image:EdExample7.gif]] This time we can get away by replacing m by 3, [[Image:EdExample8.gif]] So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== fbc0f252fcad12b0d9b6f5edee3cef874f031174 1 530 1210 2006-03-30T01:41:55Z Colin Kaminski 0 Talk:Holography Transmission Equations moved to Talk:Holography Transmission Equations Part I: Better title. wikitext text/x-wiki #redirect [[Talk:Holography Transmission Equations Part I]] a29f0012f3a5f91906060add6a7f197dc97c703a 1 531 1212 2006-03-30T01:41:55Z Colin Kaminski 0 Talk:Holography Transmission Equations moved to Talk:Holography Transmission Equations Part I wikitext text/x-wiki Ed- This is very nice! Can we move the TEA discussion to the Wiki? Give me te permission and I will make the changes. This sentence might need to be revised a little: "Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle!" Perhaps this is more clear: "Starting in the green means you have to post-swell to get red, (another, different, kind of headache!) the farther the shifted frequency is from the recording frequency the lower the deffraction efficience is and the dimmer the resulting hologram becomes at the same angle!" In order to upload your picture Click on the little image icon above the editing pane and it will insoert an example link. Edit it to a good name for you file. It does not have to be the same name as your original file. When you save the page and read it, click on th elink and it will prompt you to upload the file. Try to make it less than 50K so it will load quickly. Playing with morier patterns helped me a lot. Perhaps I can make a Java Applet to insert into your article. I'll work on it. Colin Ed, Sweeeeeet! JohnFP 01ab656eb2bbca37a7d97907529460d19d7e0b1a 0 162 171 2006-03-30T01:42:15Z Colin Kaminski 0 wikitext text/x-wiki Holograms can be made with no mathematics. However, there is a mathematical basis for all of holography. Below we will explore the mathematical basis for holography. *[[Holography Transmission Equations Part I]] by Ed Wesly *[[Holography Transmission Equations Part II]] by Ed Wesly *[[The Calculus of Holography]] bb014b1458ba31d18d2bc5d1320340d2ae41742f 0 506 1162 2006-04-02T03:54:55Z Colin Kaminski 0 /* Notes */ wikitext text/x-wiki =SHSG for PFG-03C and PFG-03M= from: *'''Transmission and Reflection SHSG Holograms''' - Kim, Choi, Choi, Kim, Kim, Bjelkhagen, Phillips - SPIE *'''SHSG processing for three-wavelength HOEs recording in Silver Halide Materials''' - Kim, Choi, Bjelkhagen, Philips - SPIE I have made some assumptions about their process. Please read the source if you are serious about this process. ==Hardening bath== *Formaldehyde (37%) 10ml *Potassium Bromide 2g *Sodium Carbonate (anhydrous) 5g *Deionized Water 1L ==Stop Bath== *2% Acetic Acid Bath ==Bleach== (pH 5) *Cupric Bromide 1g *Potassium Persulfate 10g *Citric Acid 50g *Potassium Bromide 20g *Borax 30g *Chromium (III) Potassium Sulfate 20g *Deionized Water 1L Add 1g Metol after everything is mixed ==Fix Bath== *Ammonium Thiosulfate (anhydrous) 10g *Sodium Sulfate (anhydrous) 20g *Deionized water 1L ==Process== *Prehardening 6 min *Develop G282C Diluted 1 to 3 to 1 to 5 3 min *Rinse Running Deionized Water at least 3 Min *Stop *Wash? *Bleach (diluted 1:3) 15 min *Warm water bath (60C) 10 min *Wash? *Dehydrate 50% IMS 3 min *100% IMS 3 min *Dry in 45C oven 5 min *Vapor harden with Formaldehyde 25 min or 50% glutaraldehyde vapor *25min *Fix 2 Min *Wash *Dehydrate 50% Isopropyl 10 min *100% 10 min *100% 70C 2min *Dry in 45C oven. Seal with Pascofix ==Notes== From Martin: The two developers mentioned in US 4108661 might be candidates for developers a la G284c: I *hydroquinone: 16.5 g *potassium bromide: 1.7 g *sodium salt of EDTA: 1.7 g *potassium metabisulphite: 40 g *1-phenyl-5-mercaptotetrazole: 35 g *sodium hydroxide and water to make: 1 liter at pH 11.8. II *hydroquinone: 25 g *potassium bromide: 2.5 g *sodium salt of EDTA: 2.5 g *potassium metabisulphite: 62.5 g *1-phenyl-5-mercaptotetrazole: 50 mg *potassium thiocyanate: 0.5 g *sodium hydroxide and water to make: 1 liter at pH 11.8 (Colin's Note: These developers have some of the features but the MSDS includes Potassium Sulphite and Hydroquinone as the only listable toxins. Info from Kim et. al. G282C is the high speed reversal prosess for AGFA Millimask Plates. "Such non-tanning developers usually contain halide solvents and encourage sharp developed edges." -------------------------------------------------------------------------------- by Martin Maybe I should have pointed to another paper (also in SPIE 4659) by a Russian group (Evstigneeva, Drozdova, Mikhailov) dealing with SHSG. The authors recorded pulsed holograms on VRP plates (which incidentally are said to come close to PFG-01). (Colin's Note: VRP is green sensitive and PFG-01 is Red Sensitive. For more details see www.slavich.com) They describe the following processing steps: #Development in a non-tanning developer (SM-6); #rehalogenating bleach (permanganate); #intermediate alcohol (ethanol) drying; #uniform second exposure; #second development in diluted developer; #reversal bleaching (dichromate); #fixing; #dehydration in isopropanol. The potassium permanganate bleach is formed by: *Pot. permanganate ................0,4g *Sulfuric acid ...................0,4ml *Sodium chloride....................10g *Water...............................1L The second developer: *Sodium sulfite ......................5g *Metol................................5g *Hydroquinone........................10g *Ascoribic acid......................10g *Phenidon.............................1g *Sodium hydroxide....................10g *Water................................1L 1ea20453957e5ea0a2e7a0452069b48d03f7d741 0 263 373 2006-04-02T19:06:32Z Colin Kaminski 0 wikitext text/x-wiki [[Colin Kaminski]] is the administrator of the HoloWiki. If you would like to help him with administration please contact him. 25c965db19299d5223150a5e91f957a4a66a4fb1 0 247 341 2006-04-03T01:49:56Z Colin Kaminski 0 wikitext text/x-wiki *[http://google.com/groups?q=$1 '''Google''' "$1"] *[http://groups.google.de/groups?q=$1&hl=de alle '''Google Newsgroups''' nach "$1" durchsuchen] dcabf0ea1afac7b5c91b524c3e25012a09d0e6cd 0 462 1074 2006-04-03T03:29:27Z Colin Kaminski 0 /* Finding P-Type Polarization */ wikitext text/x-wiki I am putting in notes. If anyone wants to add to this feel free. Definition: [[Image:Reflection_Polarization.png]] Reflection of a plane wave from a surface perpendicular to the page. The p-components of the waves are in the page, while the s components are perpendicular to it. rpar=(tan^2(alpha-beta)/tan^2(alpha+beta) rperp=(sin^2(alpha-beta)/tan^2(alpha+beta) alpha=angle of incedence beta=transmitted angle ===S-Type=== [[Image:SPolarization.jpg]] S-Type ===P-Type=== [[Image:PPolarization.jpg]] P-Type Polarizaton P-Polarization is used when you need to minimize the reflection off an interface between two materials of differing index of refraction. The index of refraction of air is about 1 and most glasses are about 1.5. For these two the angle of least reflection is about 56 deg. and is known as the [[Brewster's Angle]]. ===Finding P-Type Polarization=== One way to determine p-polarization is to set up your plateholder at [[Brewster's Angle]] (about 56 deg) and place a single piece of glass in it. Hit the glass with your spread beam. The glass is going to reflect some of the light hitting it, so place a white card in this reflected light path (in order to view it). If you rotate your laser head, you will notice that this reflected light becomes brighter and dimmer. Find the spot within the rotation where the reflected light is at it's dimmest on your white card, and you've got it. There should be two spots for this with every 360-degree of rotation. With a HeNe, you'll always have a "little" bit of light reflected. With a properly-running diode, the reflection will go completely out on the card (100% -- or VERY close to 100% -- transmission through the glass). ===Finding S-Type Polarization=== The easiest way to find S-Type Polarization is to find P-Type first and mark the top of your laser. Rotate the laser 90 degrees and you are at S-Type. Another method is to make a set up like for finding P-Type Polarization and place a light meter in the reflected beam. Adjust the rotation of the laser until the reflected light is a maximum. ===Testing Materials for Bifingence=== Many plastics will act as a bad wave plate. They will take your linear polarized laser beam and make it elliptical. Fortunatly there is a easy way to check. Place the sample of the material in question in between two crossed polarizers. If you see colors then it is acting to rotate the polarization. [http://en.wikipedia.org/wiki/Polarization Wikipedia's Article on Polarization] 6b2781b5f97dd66f881108bb66e89901d362d9de 6 77 771 77 2006-04-03T03:42:07Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 76 769 76 2006-04-03T03:51:42Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 201 249 2006-04-04T14:23:28Z Colin Kaminski 0 wikitext text/x-wiki Because of the expense of making these crystals they are usually quite small. The can be quite thick compared to other mediums and can store a large number of holograms. The exposure energy is quite high and they are erased by light so reading the stored hologram degrades the image. Some researchers have gotten around the erase problem of these crystals. For further information see the the references at the bottom of the page. ==Lithium Niobate== Fe-doped LiNbO3 crystals have been used to store holograms. These crystals are only Available in small sizes but they are available in large thicknesses compared to traditional materials. This thickness can be used to make holograms that can be made to read different holograms when the reference beam comes from different angles. Reading the hologram at the same frequency as writing it will cause degredation of the image. The exposure requirement is quite high at about ^4 J/m^2. The interested researcher should refer to Petrov, M.P. (1979) Light diffraction from volume holograms in electro-optic bifringent materials. Optics and Laser Technology. 11, 149-151. ==Barium Titanate== BaTiO3 ==Sr.75Ba.25Nb2Og== ==BSO== Bi12SiO20 Exposure requirement - 3J/M^2. This material is used with an applied field perpendicular to the fringes. This applied field can be up to 900V/mm. Information storage length for dark storage is reported to be only 30 hours. ==BGO== Bi12GeO20 ==References== Optical Holography, P. Hariharan, 1996, ISBN 0521439655 52216d19493eadf5db5b6546072e8ea3c8087531 0 216 279 2006-04-05T05:48:16Z Kaveh 0 wikitext text/x-wiki Here is a [http://rudieberkhout.home.mindspring.com/SPIE-Acompactdisplay.htm Great Article] by [[Rudie Berkhout]]. 2dc1ff8bef87677ee63899438d74c914cfdfcd7e 6 10 857 10 2006-04-07T01:33:52Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 9 855 9 2006-04-07T01:34:54Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 493 1136 2006-04-07T01:36:11Z Colin Kaminski 0 wikitext text/x-wiki [[Image:SVorobyov.jpg]] A physicist, expert in holography, Ph. D. of technical sciences. Sergey Vorobyov has been studying holography since second year of the university. During 30 years of his work, he took part in the development of the main directions of applied holography - hologram manufacturing on silver-halide photomaterials, hologram production on dichromate gelatin, manufacturing of holograms for information systems, embossed and color holography and etc. Sergey Vorobyov was a member of the commission on industrial application of photoplates for holography: PFG-01, PFG-02, PFG-03, PFG-04 at the Slavich company. He took part in testing those plates and optimization of the manufacturing process. Sergey Vorobyov is director of holographic studio at the All-Russian Exhibition Center (Moscow). He developed unique technology of recording and copying of pulse holograms. Commercial manufacturing of display holograms has been organized with his help. Sergey constantly improves technology of manufacturing of transmission and reflection holograms. As a holography popularizer he wrote the course "25 holography lessons". It has been published in Russian and English on [http://www.holography.ru www.holography.ru] web site. Sergey Vorobyov also developed the compact kit for amateur holography. f198df26477f86b0c9892de50a49c1b2ea8cecbb 0 494 1138 2006-04-07T01:37:28Z Colin Kaminski 0 wikitext text/x-wiki [[Image:SZharkiy.jpg]] Sergey Zharkiy graduated from the Moscow State University, Faculty of Physics with a MS (Master of Science) in Physics in 1999. He studied lasers and holography at the International Laser Center of Moscow State University. He took part in scientific conferences with his articles on holography and laser applications. Sergey Zharkiy is an author and developer of [http://www.holography.ru Holography.Ru] web site. He wrote and translated many articles for this web site. Sergey also designed and made several art holograms for gallery of Russian Holographic Studios. Sergey Zharkiy took part in development of compact holographic kit for amateur holographers. He is also author and director of educational film (DVD) on holography. 38787c57278d1cf03021f1544097ac7ecf9e658e 0 173 193 2006-04-07T02:07:32Z Colin Kaminski 0 wikitext text/x-wiki [http://www.lasart.com Lasart] 0bd5063994c88bb56707ba655937ebc3c2b024fc 6 36 667 36 2006-04-08T13:55:40Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 37 669 37 2006-04-08T13:56:28Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 38 671 38 2006-04-08T13:56:54Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 39 673 39 2006-04-08T13:57:24Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 396 943 2006-04-08T14:08:49Z Colin Kaminski 0 wikitext text/x-wiki '''A simple spatial filter design''' by John Klayer A few people asked to see my design, so here it is. It was published in the L.A.S.E.R. News Vol. X #4 Winter 1990-1991. It is very easy to use and not too difficult to build. [[Image:JKSpatialFilter1.jpg]] '''Parts list:''' '''A Carriage:''' 1/4 by 1-3/4 by 2-1/2 inch plexiglas. A 1-1/4 inch hole is centered 7/8 inch from the top. The top and one side are drilled and tapped to receive D1 and D2. A slot is filed at 45 degrees to receive F. (See the drawing below for an alternate method.) A hole is centered, drilled and tapped 3/8 inch from the bottom to receive E. Two holes 3/8 inch from the bottom and 1/4 inch from each side are drilled thru the carriage and the base h to receive I1 and I2 - use a #6 drill. (These holes need to be drilled thru the carriage and base in one operation.) Around the 1-1/4 inch hole three holes are drilled and tapped 120 degrees apart for the 2-56 screws that secure the fender washer C. '''B Magnet:''' A 1-1/8 inch ring magnet available from Radio Shack. '''C Plate:''' a 1-5/8 by 5/16 inch fender washer with three holes drilled 120 degrees apart for the 2-56 by 1/4 screws that secure it to the carriage A. '''D1, D2 Fine Positioning Screws:''' 0-80 by 1/2 machine screw, end rounded and fashioned into a thumbscrew by soldering onto the head the knurled disk part cut from a 10-32 knurled nut. The 10-32 knurled nut is cut by putting it on a 10-32 screw and turning it with a drill while applying a hacksaw blade. The soldering task can be simplified by using a wooden fixture to align and hold the knurled disk and the 0-80 screw: Bore a flat bottom hole 1/2 inch diameter by 1/8 inch deep into a block of wood then continue concentrically with a 1/16 inch hole. (I've thought about replacing the 0-80 screws with 2-56 screws.) '''E Focusing Adjustment:''' Same as D1 and D2 but use a 3/4 inch screw. '''F Spring:''' Closed and ground ends, length from 3/8 to 5/8 inch, about 1/8 inch diameter. '''G Pinhole Holder and Coarse Adjuster:''' Any piece of ferrous metal shaped similar to the illustration. Glue the pinhole to the ring part. The ring and handle should be able to lay flat against the magnet - this is important, otherwise the ring would be drawn to the magnet center and there wouldn't be any coarse adjustment. The handle part should extend beyond the edge of the carriage. You may find an item like this at a hardware store called a "ring hanger". '''H Base:''' 3/4 by 1-1/2 by 1-3/4 inch block of wood. Two holes drilled thru it 3/8 inch from the bottom and 1/4 inch from each side. These holes must align perfectly with the two in the carriage,A. To assure alignment, start with a sheet of plexiglas and a piece of wood about 2 inches wider, attach the plexiglas firmly to the wood with two wood screws and drill thru both, the saw to the 1-3/4 inch width. Make a notch 3/4 inch wide and 1/8 inch deep in the front to receive K. Centered on the top, drill a 3/4 inch flat bottomed hole partially thru and continue concentrically with a 5/16 inch hole the rest of the way to hold L. '''I1,I2 Sliding Shabts:''' Three inch aluminum screw posts (manufactured by Charles Leonard, Inc.) available from office supply stores. The normal use is for binding books. These have two heads, one attached to the shaft and the other screws into the other end. Insert the posts thru the carriage and base so that the screw end is to the back. Epoxy the front 1/4 inch of the posts inside the carriage holes. '''J1,J2 Focusing Springs:''' Any spring that will fit over the shaft with a lenght of about 1-1/2 inch and not too stiff. '''K Lens Mount:''' 3/4 by 1/8 inch aluminum. 1-5/8 inch from the bottom drill a hole the diameter of the lens. Drill and countersink two holes 3/16 and 9/16 inch from the bottom for two wood screws to secure it to the base. '''L Fastener:''' 1/4-20 by 3/4 inch T-nut secured in the hole in H by three small wood screws. This is to provide a means of mounting the assembly on a post. '''Lens:''' You could use a simple lens. What I found works real well is a "Hastings Triplet" from Edmund Scientific. Forget the microscope objectives. ---- An alternate design for the carriage magnet spring: [[Image:JKSpatialFilter2.jpg]] Here I'm using a hole drilled at 45 degrees with a head of a small nail against the magnet, a small spring held in the hole by a short section of brass tube epoxied in the hole. I used clear plexiglas for the first few I built then I found some black plexiglas. Use the black if you can find it. If you never tried drilling a 1-1/4 inch hole in plexiglas before, you're in for a real treat. I'm sure there are plenty other materials you can try besides plexiglas and wood. These materials worked for me. Good luck. [[Image:JKSpatialFilter3.jpg]][[Image:JKSpatialFilter4.jpg]] a5b093683c0ce3dbf5a285204c93642a182af9f0 0 425 1000 2006-04-09T17:38:56Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Mackie line''' - an effect sometime found on a negative or print, in which a light line forms along the boundaries of the darkest image areas. It may also be caused during processing by the diffusion of exhausted developer, lack of agitation, or by solarization. *'''Macrophotography''' - photography which produces an image larger than the original subject size without the use of a microscope. *'''Magazine''' - a light-tight container holding roll film. *'''Magnification''' - the size of the image relative to the size of the subject used to produce it. It is an expression of the ratio of the subject-lens distance to the image-lens distance. When object distance = image distance, magnification = 1. *'''Mask''' - an opaque material used to cover the edges of the printing paper, and thus produce borders when the paper is exposed to light. *'''Masking''' - a system of controlling negative density ranges or color saturation through the use of unsharp masks. *'''Masking frame''' - an adjustable frame used to hold printing paper in position under the enlarger, also referred to as an enlarging easel. *'''Mastic varnish''' - varnish used for negatives. *'''Mat''' - an alternative term used for matte. Also describes the cardboard surround in a picture frame. *'''Matte field''' - a granular textured surface that disperses light in order to form a clear image. Used in the viewfinder optical system. *'''Matrix''' - a relief image, usually made from gelatin and used for processes such as dye transfer printing. Also a pretty good movie. *'''Matte''' - a term used to describe a non reflective, non-textured surface. *'''Matte box''' - a mask used to make images suitable for wide-screen projection. *'''Mercury vapor lamp''' - an artificial light source produced by passing current through mercury vapor in a tube. *'''Metal print''' - a photographic print made on a sensitized metal surface *'''Microfiche''' - a sheet of microfilm usually forming part of a filing system. *'''Microfilm''' - a film used to produce a microscopic record of a document and intended for projection. *'''Microflash''' - an electronic flash of very short duration used to illuminate subjects traveling at a very high rate of speed. *'''Micron''' (µ) - is one millionth of a meter. *'''Microphotograph''' - a photograph produced to a very small size which can be viewed with a microfilm reader. *'''Microprism collar''' - a grid type ring found in the center of a camera focusing screen, usually surrounding a split image screen. *'''Midtone''' - an area in a print or scene that contains average values. *'''Millimicron''' (mµ) - one thousandth part of a micron. (Also one nanometer) *'''Mired''' - an abbreviation for the term micro reciprocal degrees, a scale of measurement of color temperature. The mired value of a light source is calculated by dividing 1,000,000 by its color temperature in Kelvins. *'''Mirror lens''' - a lens system which uses mirrors within its internal construction. Most lenses of this type have a mixture of reflecting and refracting optics and are known as catadioptric lenses. *'''Microfiche''' - a sheet of microfilm usually forming part of a filing system. *'''Modeling light''' is a light used to create a three dimensional effect achieved through the perception of form and depth. *'''Modelscope''' - a device employing a short rigid endoscope fitted with a right angle mirror at its tip, used to photograph scale models from a seemingly eye-level viewpoint *'''Modular enlarger''' -an enlarger with interchangeable filtration heads and illuminations systems. *'''Monobath''' -a single solution which combines developer and fixer for processing b&w negatives. It is a quick simple system but does not allow for development control. *'''Monochromatic''' - light rays of a single wavelength. Monochrome is single colored. It is most frequently applied to black and white photographs, but can also describe sepia and other toned images. *'''Monopack''' - an outdated term describing a film carrying system. *'''Monorail camera''' - a sheet film camera, of modular construction, mounted on a rail system to give maximum camera movements. *'''Montage''' - a composite picture made from a number of photographs. *'''Mordant''' - a colorless dye absorbing substance used in some forms of toning. The silver image is converted into a mordant then soaked in dye. *'''Mosaic''' - a composite made up from a patchwork of partly overlapping photographs. *'''Motor drive''' - an automatic film wind-on mechanism which can be attached to some cameras. While the shutter remains depressed the film will keep winding on after exposure. *'''Mottle''' - a processing fault characterized by random print density differences. *'''Mount''' - a frame and/or backing used to support and protect prints and transparencies. *'''MTF''' (Modulation transfer function) - A comparison of contrast between a test chart and the reproduced image. One of the measurements of lens performance used in the manufacturing process. *'''Mercuric chloride''' - a chemical used in certain types of intensifiers. *'''Methyl alcohol''' - a volatile, poisonous spirit commonly known as wood alcohol. Used as a substitute for pure alcohol in some photographic processes. *'''Metolquinone''' - a combination of metol and hydroquinone, used as a developing agent (MQ developer). *'''Mordant''' - a colorless dye absorbing substance used in some forms of toning. The silver image is converted into a mordant then soaked in dye. *'''Multi-band photography''' - a method of aerial photography using cameras and scanners which are sensitive to different wavelengths in the spectrum to record different subject characteristics. *'''Multiple exposure''' - the technique of making more than one exposure on the same film frame, normally so that the images are superimposed. *'''Multiple flash''' - the use of more than one flash unit, usually operating simultaneously to light a subject. Can also be multiple modelocked lasers. *'''Munsell system''' - a method of precise color description, based on comparison with comprehensive hue and saturation charts. Has closest application to pigments, whereas the CIE system relates directly to light. 2dd0db6852e00fb5557ff51dc0afb40b6c6479c1 0 394 939 2006-04-09T17:39:22Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Joule''' - unit used to quantify the light output of electronic flash. A joule is equal to one watt second of 40 lumen-seconds. The measure is used to compare flash units in terms of power output. f9aead7abea7dec4702846f11147816eade568f6 0 401 953 2006-04-09T17:39:49Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Kallitype''' - obsolete printing process, resembling the platinum process. The image is formed in metallic silver rather than expensive platinum. *'''Kerr cell''' - high speed shutter without moving parts, using two crossed polarizing filters at either end of a cylinder filled with nitrobenzine. *'''Key light''' - studio light used to control the tonal level of the main area of the subject. *'''Knifing''' - method of removing marks and other blemishes from the surface of a print by gentle scraping with the tip of a sharp knife. *'''Kostinsky effect''' - development effect in which dense image points are inclined to move apart, relative to each other, and light image points to move together, relative to each other. This occurs because developer is not being equally distributed over the image point and is rapidly exhausted when to heavily exposed image points are close together. *'''Kromskop''' - early viewing instrument invented by F.E. Ives, embodying a system of mirrors and color filters to synthesize a full color image. This enabled monochrome transparencies made from separation negatives to be rear-illuminated through blue, green and red filters, and then been seen combined in register as a single image. 73a8c06e88bb82b05dc9d587ce9abbbd3b016129 0 442 1034 2006-04-09T19:53:45Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Nadar''' - the name adopted by the first aerial photographer, G. F. Tournachon, who took photographs from an air balloon. *'''Nanometer''' - a unit of measurement of light wavelength. A nanometer is one millionth of a millimeter. (1/1000 micron; 10 angstroms). *'''Naphtha''' - a volatile petroleum based solvent such as benzine or gasoline (but not kerosene). *'''ND''' - an abbreviation for neutral density. *'''Near ultraviolet''' - wavelengths from about 400nm down to 250nm. Most photographic emulsions are sensitive to this range of bands. *'''Negative''' - the image produced on a photographic emulsion by the product of exposure and development, in which tones are reversed so that highlights appear dark and shadows appear light. *'''Negative carrier''' - supports the negative between the light source and the enlarging lens of an enlarger. *'''Neutral density''' - a technique which makes possible shorter printing times in color printing. *'''Neutral density filter''' - a gray camera filter which has an equal opacity to all the colors of the spectrum and so does not affect the colors in the final image. It is used to reduce the amount of light entering the camera when aperture or shutter settings must remain constant. *'''Neutral filtration''' - in color printing is the filtration at which color balance is achieved, rendering a neutral gray ion the film image as a neutral gray on the photographic paper. *'''New Objectivity''' - an approach to the subject matter of photography originating in Germany in the 1920s. The photographer remains an impartial observer, intensifying the appreciation of forms and structures in ordinary things but de-personalizing his/her approach. *'''New Realism''' - an alternative name for New Objectivity. *'''Newton's rings''' - rings of colored light produced when two glass or transparent surfaces are in partial contact. *'''Nitrate base''' - an early flexible film support which was highly inflammable. *'''Nitric acid''' - used in emulsion manufacture, in toners, and in bleaches, it is highly corrosive. *'''Nodal plane''' - an imaginary line passing through the nodal point, perpendicular to the optical axis. *'''Nodal points''' - located in two areas in a compound lens system. The front nodal point is where rays of light entering the lens appear to aim. The rear nodal point is where the rays of light appear to have come from, after passing through the lens. Nodal points are used to calculate optical measurements. *'''Non-silver processes''' - image making processes that do not require the use of metallic silver, such as Gum bichromate. *'''Non-substantive''' - a name given to color film in which the color couplers are not contained within the emulsion, but are introduced during processing. *'''Notch''' - a V or U shaped cut into one edge of sheet film. It denotes the location of the sensitive side of the film as well as identifying the type of film. 15e583db5653b446d87dde8ee1c9c525a3349621 0 447 1044 2006-04-09T19:55:49Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Off the film metering''' - a meter which determines exposure by reading light reflected from the film during exposure. Pioneered by Olympus on its OM2n. Most flash modes have OTF. *'''Oil reinforcement''' - a method of altering the tonal range of prints on matte or textured fiber papers. The dried print is rubbed with a medium consisting of two parts of turpentine to one of mastic varnish and one of linseed oil. Artists oil color is then applied locally to the print. *'''One shot color camera''' - an obsolete plate camera making three color separation negatives from a single exposure. *'''One shot developer''' - a developer that is used on a single occasion and then discarded. *'''Opacity''' - the light stopping power of a a material. The greater the opacity of a substance, the more light its stops. In photography, opacity is expressed as a ration of the amount of light falling on the surface of the material to the amount of light transmitted by it. *'''Opalescent''' - like opal, a material with a cloudy-white translucent appearance. *'''Opal lamp''' - a filament lamp with an opal glass bulb for optimum diffusion. *'''Opalotype''' - an obsolete printing process in which a carbon-process image is transferred on to translucent opal glass. *'''Opaque liquid''' - a dense red or black pigment, dissolved in water to form a liquid paint used to fill in film areas that are required to pint as pure white. *'''Optical axis''' - an imaginary line passing horizontally through the center of a compound lens system. *'''Optical bench''' - a device for measuring the optical performance of lenses. Holographers usually use horizontal planes called ‘tables’. *'''Optical glass''' - used for manufacturing lenses and prisms. It is specially manufactured to be free of defects and distortion, and to withstand heat and humidity. Each type f optical glass is classified according to its refractive index and light dispersive quality. Two or more types of optical glass are typically used in the component elements of photographic lenses. *'''Optical sensitizing''' - a method of increasing a films sensitivity by the use of dyes. *'''Optical wedge''' - a strip of material, clear at one end and gradually increasing in opacity, which is used to determine the effect of light intensities on sensitized materials. *'''Optics''' - the science dealing with the behavior of light. *'''Ordinary emulsion''' - a term applied to a photographic emulsion which is only sensitive to ultra-violet and blue light. *'''Orth-phenylene diamene''' - a fine-grain developing agent. *'''Orthochromatic''' - used to describe an emulsion which is sensitive to blue and green light, but insensitive to red. *'''Over-development''' - a term indicating that the amount of development recommended by the manufacturer has been exceeded. It can be caused by prolonged development time or an increase in development temperature, and usually results in an increase in density and contrast. *'''Over-exposure''' - an expression used to indicate that the light sensitive material has been excessively exposed. *'''Oxalic acid''' - soluble white crystals used in some toners. *'''Oxidation product''' - the chemical produced by a color developer during the conversion of exposed silver halides to black metallic silver. 55a371f78711c9eea77aece159b86dddf9495a22 0 452 1054 2006-04-10T03:34:15Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Painting with light''' - technique of lighting large, dark interior. The camera, mounted on a tripod, is given a long time exposure. The photographers moves continuously around the interior, giving flash or battery powered photoflood illumination to the shadow areas. *'''Panchromatic''' - photographic emulsion sensitive to all the colors of the visible spectrum and to a certain amount of ultra-violet light. The sensitivity is not uniform throughout the spectrum. *'''Panchromatic vision filter''' - filter through which the subject can be viewed approximately as it would appear in monochrome as recorded by a panchromatic emulsion. *'''Panning''' - technique of photographing moving subjects. While the shutter is open, the camera is swung in the same direction as the subject is moving. This creates a blurred background, but a sharp subject. *'''Panorama''' - picture presenting a continuous view of the landscape, produced either by using a panoramic camera or from a composite of several images. *'''Panoramic camera''' - camera with a special type of scanning lens which rotates on its rear nodal point and produces an image of the scanned area on a curved plate or film. *'''Parallax''' - difference between the image seen by a viewing system and that recorded on film. Only TTL viewing systems avoid parallax error. *'''Paraphenylenediamine''' - reducing agent used in some fine grain and color developers. *'''Paraphotography''' - general term for non-silver-halide image forming processes. *'''Paraxial''' - rays nearest the optical axis of a lens. *'''Patch chart''' - squared pattern test strip often made when color printing by the additive method. *'''Pellicle''' (pellicule) - thin film used in one-shot color cameras as a semi-reflecting surface. *'''Percentage solution''' - solution containing a given quantity of a dissolved substance in a stated volume of solvent. *'''Perforations''' - accurately spaced holes punched throughout the length of film for still cameras. Basically the perforation function as a guide for precision registration of film and also provide mechanical movement from frame to frame. *'''Periphery photography''' - technique used to photograph the entire inner or outer surface of a cylinder or tube. *'''Permanence tests''' - methods of establishing whether long term permanence of an image has been achieved. *'''Perspective''' - relationship of size and shape of three-dimensional objects represented in two-dimensional space. *'''pH scale''' - numerical system running from 0-14 and used to express the alkalinity or acidity of a chemical solution. 7 is neutral. Solutions with a lower pH value are increasingly acidic, and those with a higher pH value are increasingly alkaline *'''Phenidone''' - reducing agent used in many fine grain solutions. *'''Phenol varnish''' - resin used to produce a hard durable top coating. *'''Phosphorescence''' - property held by some materials of absorbing light of one wavelength and emitting it as light of a different wavelength. *'''Phosphotophotography''' - technique of projecting an infrared image on a phosphorescent surface. *'''Photo color transfer''' - method of making color enlargements by exposing on full size sheet film which is then soaked in a activator solution and rolled in face contact with receiving paper. The sandwich is then left in normal light for 6-8 minutes and peeled apart to give a finished print. *'''Photo elasticity''' - method of determining stress patterns in structures with the aid of polarized light. *'''Photo-electric cell''' - light sensitive cell. Two types are used in exposure meters. A selenium cell generates electricity in proportion to the amount of light falling upon its surface. A cadmium sulfide cell offers a resistance to a small electric charge when light falls upon it. Cadmium sulfide cells are more sensitive then selenium, especially at low light levels. *'''Photo-engraving''' - production of a relief printing surface by chemical or mechanical means, with the aid of photography. *'''Photo-etching''' - technique of contact printing an image on lith film on a presensitized zinc plate which is then processed and chemically etched to give a relief image. *'''Photogenic drawing''' - original name given by William Fox Talbot to his earliest method of recording camera images. *'''Photogram''' - pattern or design produced by placing opaque or transparent objects on top of a sensitive emulsion, exposing it to light and then developing it. *'''Photogrammetry''' - method of making precise measurements from photographs. *'''Photography''' - literally writing or drawing with light (from the Greek words photos meaning light and graphos, writing). First suggested by Sir John Herschel to William Fox Talbot in 1839. *'''Photogravure''' - method of printing photographs from an etched copper plate. *'''Photolinen''' - laminate of linen and paper coated with black and white photographic emulsion. It is used for photographic wall coverings. *'''Photolithography''' - lithographic printing process using an image formed by photographic means. *'''Photometer''' - instrument for measuring light being reflected from a surface. It works by comparing the reflected light with a standard source produced within the photometer. *'''Photomicrography''' - system of producing larger than life photographs by attaching a camera to a microscope. *'''Photon''' - particle of light energy. It is the smallest quantity of radiant energy that can be transmitted between two systems. *'''Photo-reportage''' - use of photographs in newspapers and magazines, to supplement or replace written journalistic accounts. *'''Photo-resistor''' - photoelectric cell which varies in its electrical resistance according to the light received. *'''Photo-silkscreening''' - method of silkscreening images, using a stencil produced photographically. *'''Photo telegraphy''' - transmission of pictures between two points by means of radio or telegraph. A print is wrapped around a cylinder and scanned by a small spot of light. Reflected light values are transmitted as a stream of signals. They control an exposing light source at the receiving station, which exposes light sensitive material on a similar drum. *'''Photo-transistor''' - light sensitive electronic component which functions as a switch. Used for slave firing of electronic flash heads. *'''pH scale''' - numerical system running from 0-14 and used to express the alkalinity or acidity of a chemical solution. 7 is neutral. Solutions with a lower pH value are increasingly acidic, and those with a higher pH value are increasingly alkaline *'''Physical development''' - system of development in which silver is contained in suspension within the developer and is attracted to the emulsion by silver halides which have received exposure. *'''Physiogram''' - photographic patter produced by moving a regulated point of light over a sensitive emulsion. *'''Pictorialist''' - photographs which are a picturesque, decorative art in their own right and appeal to the viewers sense of beauty. *'''Piezo-electric flash''' - tiny flash bulbs (normally housed in flash cubes) which can be fired by a very low current produced by striking a piezo-electric crystal. Such bulbs can therefore be used without a battery. *'''Pigment''' - coloring material that is insoluble in the liquid carrier with which it is mixed. Examples include paint or poster color. *'''Pigment processes''' - making a positive print by using the property of bichromated colloids by changing their physical characteristics with exposed light. Gum bichromate is a pigmented process. *'''Pinacryptol''' - yellow and green dye powders which are used in desensitizing solutions. *'''Pincushion distortion''' - lens aberration causing parallel, straight lines at the edge of the image to curve toward the lens axis. *'''Pinhole camera''' - camera without a lens which uses a very small hole pierced in one end to allow light to pass through and form an image on the back of the camera which can be covered by film. *'''Pixels''' - abbreviation for picture elements. The tiny squares of light making up the picture are transmitted in digital form and reconstituted as a visual image. *'''Plane''' - imaginary straight line on which image points may lie or which passes at right angles through a set of points perpendicular to the optical axis. *'''Plates''' - early photographic glass plates coated with emulsion. *'''Plate camera''' - camera designed to take glass plates but often adapted to take cut film. *'''Platinotype''' - obsolete contact printing process popular among pictorialists. *'''Point source lamp''' - arc type lamp producing light from a small gap between two carbon rods. *'''Polarization''' - light said to travel in a a wave motion along a straight path, vibrating in all directions. Polarization can be brought about with a polarizing filter which causes light to vibrate in a single plane only. Polarizing filters are used over camera lenses and light sources to reduce or remove specular reflection from the surface of objects. *'''Polarized light''' - rays of light that have been restricted to vibrate in one plane only. *'''Polarizing filter''' - colorless gray filter made from stressed glass. Polarizing filters are used over light sources or camera lenses to reduce or remove specular reflection from certain types of surfaces. *'''Pola-screen''' - another term for a polarizing filter. *'''Portrait lens''' - lenses produced specifically for portraiture. They usually have a long focal length and produce a slightly diffused image. *'''Potassium bromide''' - chemical used as a restrainer in most developing solutions and as a rehalogenizing agent in bleaches. *'''Potassium carbonate''' - highly soluble alkaline accelerator used in most general purpose and print developing solutions. *'''Potassium chloride''' - chemical used in some bleaches and sensitizers. *'''Potassium citrate''' - chemical used in blue and green toners. *'''Potassium ferricyanide''' - chemical used in Farmer's reducer as a bleach. *'''Potassium hydroxide''' - caustic potash. Highly active alkali, used as the basis for high contrast developing solutions. *'''Potassium iodide''' - chemical used in bleaches, toners and intensifiers. *'''Potassium metabisulfite''' - acidifier used in fixers and stop baths. *'''Potassium permanganate''' - chemical used extensively in reducers, bleaches and toners. *'''Potassium persulfate''' - chemical sometimes used in super-proportional reducers. *'''Potassium sulfide''' - chemical used in sulfide toning. *'''Potassium thiocyanate''' - chemical used in some fine grain developers as a silver solvent. *'''Positive''' - in photography, the production of prints or transparencies in which light and dark correspond to the tonal range of the original subject. *'''Posterization''' - photographic technique using a number of tone separated negatives which are printed on high contrast material. A master negative is made by printing these in register. The final print from this contains selected areas of flat tone in place of continuous tone. Sometimes incorrectly referred to as solarization. *'''Potassium Dichromate''' - sensitizer use to make Dichromated Holograms and also use in some Silver Halide Bleaches. *'''Prehardener''' - chemical solution used to harden the gelatin of an emulsion prior to processing. *'''Preservative''' - chemical, commonly sodium sulfite, used in developing solutions to prevent rapid oxidation of the reducing agents in use. *'''Preset focus shooting''' - technique in which focus is set at a predetermined setting and the shutter is released when the subject moves into the focus point. *'''Pre-soak''' - preparatory water bath for film or paper prior to processing that prevents uneven development. It is essential in some color processes. *'''Principal axis''' - imaginary line which passes through the center of curvature of all the lens elements. *'''Principal planes''' - imaginary lines which pass through the nodal planes of a lens system. *'''Principal point''' - point from which the focal length is measured. The principal point of a simple lens is located at the center of the lens. Compound lenses have two principal points, the location of which cannot be determined by appearance. *'''Processing''' - sequence of steps whereby a latent photographic image is converted into a visible, permanent image. *'''Projection cutting''' - any method of printing in which the image is optically projected on the sensitized material. *'''Projector''' - apparatus used to display enlarged still or moving images on to a screen. *'''Protective toning''' - toning process used to protect black and white prints from fading and give archival permanence. Usually used selenium or gold toners. *'''Pulling''' - method of underrating the normal ISO speed of a film to produce an overexposed latent image. *'''Pushing''' - method of overrating the normal ISO speed of a film to produce an underexposed latent image. Used to increase the working speed of a film. *'''Push processing''' - increasing the development time of a film to increase its effective speed. See Pushing. 9056b84e333387f2f5e34acc93d192ce0cf4080b 0 472 1094 2006-04-10T03:47:44Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Rack and pinion focusing''' - mechanical focusing system used on copying or monorail cameras. A pinion engages a rack on a slide. Focusing is achieved by turning a knob or wheel, which moves the lens or image panel. *'''Radiography''' - technique of using X-rays, gamma rays and charged particles to form shadow images on photographic materials. Used in medical and industrial research because of its ability to penetrate opaque objects. *'''Rayographs''' - term coined by Man Ray and his friends for pictures made by placing directly on photographic paper (i.e. photograms). *'''Rear focus''' - refers to the focused area behind the picture's subject. *'''Rebate''' - margin on photographic film surrounding the image area. *'''Reciprocity failure''' - in photographic emulsions occurs when exposure times fall outside a films normal range. At these times an increase in exposure is required in addition to the assessed amount. This can be achieved either by increasing intensity or time. *'''Reciprocity law''' - states that exposure = intensity x time, where intensity is equal to the amount of light and time is equal to the time that amount of light is allowed to act upon the photographic emulsion. *'''Reconstituted image''' - photograph produced by translating light from the subject into electronic signals. *'''Red eye''' - effect encountered when light from a flash unit travels parallel to the lens axis during exposure. *'''Reflected light''' - light bounced off a subject, not falling on it. *'''Reflected light reading''' - measurement by a light meter of the amount of reflected light being bounced of the subject. The light meter is pointed towards the subject. *'''Reflections''' - rays of light which strike a surface and bounce back again. Specular reflection occurs on even, polished surfaces; diffuse reflection occurs on uneven surfaces, when light scatters. *'''Reflector''' - any substance from which light can be reflected. It also describes a white or gray card used to reflect from a main light source into shadow areas. *'''Refraction''' - change in direction of light rays as they pass obliquely from one transparent medium to another of different density, e.g. air to glass. *'''Refractive index''' - numerical value indicating the light bending power of a medium such as glass. The greater the bending power, the greater the refractive index. *'''Register''' - exact alignment when overlaying separate images. *'''Register punch''' - punched used to make alignment holes in film or paper for registering images. *'''Rehalogenization''' - process by which black metallic silver is converted back to silver halides. It is used in bleaching for toners and intensification. *'''Relative aperture''' - measurable diameter of the diaphragm divided by the focal length of the lens in use and expressed in terms of "f" numbers, marked on the lens barrel. *'''Replenishment''' - addition of chemicals to a processing solution to maintain its characteristics, e.g. developers are replenished with reducing agents as the old ones are exhausted through use. *'''Resin coated paper''' (RC) - printing paper with a water repellent base. RC Paper can be processed faster, require less washing, and dry more quickly than fiber based papers. *'''Resist''' - protective but removable layer applied to a surface in the form of a pattern or image. Used to prevent chemicals solutions reaching covered areas. *'''Resolving power''' - ability of the eye, lens or photographic emulsion to determine fine detail. In photography, the quality of the final image is a result of the resolving power of both the lens and the sensitive emulsion. Resolution is expressed in terms of lines per millimeter which are distinctly recorded or visually separable in the final image. *'''Restrainer''' - chemical constituent of developing solutions which helps prevent reducing agents from affecting unexposed halides and converting them to black metallic silver. *'''Reticulation''' - regular crazed pattern created on the emulsion surface of negatives which is caused by extreme changes of temperature or acidity/alkalinity during processing. *'''Retouching''' - after treatment carried out on a negative or print, in the form of local chemical reduction, local dye or pencil additions or air-brushing. The purpose is to remove blemishes on the negative or print. *''Reversal materials'' - materials specifically designed to be processed to a positive after one camera exposure. *'''Rising front''' - camera movement enabling the front lens panel to be raised or lowered from its central position on most view cameras. *'''Rods''' - receptors forming part of the retina at the back of the eye sensitive only to variations in brightness, not color. See Cones. ae2215a0d0b8fbb855afdf6b14544933ba44d34d 6 95 421 95 2006-04-12T20:46:28Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 187 221 2006-04-12T20:55:43Z Colin Kaminski 0 /* Using a Pair of Anamorphic Prisms */ wikitext text/x-wiki This is a article stub. ==Using a Pair of Cylindrical Lenses== It is easiest to think of this method as a telescope for one axis only. InputD/OutputD=fl1/fl2 when the lenses are at fl1+fl2 distance apart. For Example: If your laser beam is 2mm wide and 7mm tall and you want to get as close to round as you can. You will align a cylindrical lens so the cylinder is on the wide axis. This will spread the beam. The second lens acts to re-collimate the beam. 2/7=1/3.5 It is easy to obtain cylindrical lenses in 25mm focal length increments from places like [http://www.edmundoptics.com Edmund Industrial Optics]. If you were to choose 25 mm and 75 mm you would be close at 1/3. Placing these lenses at 100mm apart your beam would be re-collimated at 6mm x 7mm which is closer to cylindrical. The laser beam does not care about the orientation of the lenses but the laser does, there are two ways to minimize the reflection back to the laser. One is to place the flat side of the lenses towards the laser and mis-align the lens so the back reflection misses the laser. The other is to place the convex surfaces towards the laser so the back reflection gets spread into a larger area. Which method you choose has to do with how close the lenses are to the laser. ==Using a Pair of Anamorphic Prisms== [[Image:AnamorphicPrism.jpg]] This drawing shows an anamorphic prism pair expanding a single axis of a laser beam. It is also posible to reduce a single axis as well. Note: only one side of each prism needs to be AR coated if the laser beam is P-Polarized as the other is close to [[Brewster's Angle]]. The two dis-advantages of this system is that the beam is displaced and it will only work on one axis if it is not AR coated on all faces. 8b62ba4170440d79a8823bc323e75038c755c1ec 0 592 1334 2006-04-15T03:22:29Z Colin Kaminski 0 wikitext text/x-wiki What is Art? by Leo Tolstoy CHAPTER FIVE (excerpts) . . . 1. In order correctly to define art, it is necessary, first of all, to cease to consider it as a means to pleasure and to consider it as one of the conditions of human life. Viewing it in this way we cannot fail to observe that art is one of the means of intercourse between man and man. 2. Every work of art causes the receiver to enter into a certain kind of relationship both with him who produced, or is producing, the art, and with all those who, simultaneously, previously, or subsequently, receive the same artistic impression. 3. Speech, transmitting the thoughts and experiences of men, serves as a means of union among them, and art acts in a similar manner. The peculiarity of this latter means of intercourse, distinguishing it from intercourse by means of words, consists in this, that whereas by words a man transmits his thoughts to another, by means of art he transmits his feelings. 4. The activity of art is based on the fact that a man, receiving through his sense of hearing or sight another man's expression of feeling, is capable of experiencing the emotion which moved the man who expressed it. To take the simplest example; one man laughs, and another who hears becomes merry; or a man weeps, and another who hears feels sorrow. A man is excited or irritated, and another man seeing him comes to a similar state of mind. By his movements or by the sounds of his voice, a man expresses courage and determination or sadness and calmness, and this state of mind passes on to others. A man suffers, expressing his sufferings by groans and spasms, and this suffering transmits itself to other people; a man expresses his feeling of admiration, devotion, fear, respect, or love to certain objects, persons, or phenomena, and others are infected by the same feelings of admiration, devotion, fear, respect, or love to the same objects, persons, and phenomena. 5. And it is upon this capacity of man to receive another man's expression of feeling and experience those feelings himself, that the activity of art is based. 6. If a man infects another or others directly, immediately, by his appearance or by the sounds he gives vent to at the very time he experiences the feeling; if he causes another man to yawn when he himself cannot help yawning, or to laugh or cry when he himself is obliged to laugh or cry, or to suffer when he himself is suffering - that does not amount to art. 7. Art begins when one person, with the object of joining another or others to himself in one and the same feeling, expresses that feeling by certain external indications. To take the simplest example: a boy, having experienced, let us say, fear on encountering a wolf, relates that encounter; and, in order to evoke in others the feeling he has experienced, describes himself, his condition before the encounter, the surroundings, the woods, his own lightheartedness, and then the wolf's appearance, its movements, the distance between himself and the wolf, etc. All this, if only the boy, when telling the story, again experiences the feelings he had lived through and infects the hearers and compels them to feel what the narrator had experienced is art. If even the boy had not seen a wolf but had frequently been afraid of one, and if, wishing to evoke in others the fear he had felt, he invented an encounter with a wolf and recounted it so as to make his hearers share the feelings he experienced when he feared the world, that also would be art. And just in the same way it is art if a man, having experienced either the fear of suffering or the attraction of enjoyment (whether in reality or in imagination) expresses these feelings on canvas or in marble so that others are infected by them. And it is also art if a man feels or imagines to himself feelings of delight, gladness, sorrow, despair, courage, or despondency and the transition from one to another of these feelings, and expresses these feelings by sounds so that the hearers are infected by them and experience them as they were experienced by the composer. 8. The feelings with which the artist infects others may be most various - very strong or very weak, very important or very insignificant, very bad or very good: feelings of love for one's own country, self-devotion and submission to fate or to God expressed in a drama, raptures of lovers described in a novel, feelings of voluptuousness expressed in a picture, courage expressed in a triumphal march, merriment evoked by a dance, humor evoked by a funny story, the feeling of quietness transmitted by an evening landscape or by a lullaby, or the feeling of admiration evoked by a beautiful arabesque - it is all art. 9. If only the spectators or auditors are infected by the feelings which the author has felt, it is art. 10. To evoke in oneself a feeling one has once experienced, and having evoked it in oneself, then, by means of movements, lines, colors, sounds, or forms expressed in words, so to transmit that feeling that others may experience the same feeling - this is the activity of art. 11. Art is a human activity consisting in this, that one man consciously, by means of certain external signs, hands on to others feelings he has lived through, and that other people are infected by these feelings and also experience them. 12. Art is not, as the metaphysicians say, the manifestation of some mysterious idea of beauty or God; it is not, as the aesthetical physiologists say, a game in which man lets off his excess of stored-up energy; it is not the expression of man's emotions by external signs; it is not the production of pleasing objects; and, above all, it is not pleasure; but it is a means of union among men, joining them together in the same feelings, and indispensable for the life and progress toward well-being of individuals and of humanity. 13. As, thanks to man's capacity to express thoughts by words, every man may know all that has been done for him in the realms of thought by all humanity before his day, and can in the present, thanks to this capacity to understand the thoughts of others, become a sharer in their activity and can himself hand on to his contemporaries and descendants the thoughts he has assimilated from others, as well as those which have arisen within himself; so, thanks to man's capacity to be infected with the feelings of others by means of art, all that is being lived through by his contemporaries is accessible to him, as well as the feelings experienced by men thousands of years ago, and he has also the possibility of transmitting his own feelings to others. 14. If people lacked this capacity to receive the thoughts conceived by the men who preceded them and to pass on to others their own thoughts, men would be like wild beasts, or like Kaspar Houser. 15. And if men lacked this other capacity of being infected by art, people might be almost more savage still, and, above all, more separated from, and more hostile to, one another. 16. And therefore the activity of art is a most important one, as important as the activity of speech itself and as generally diffused. 17. We are accustomed to understand art to be only what we hear and see in theaters, concerts, and exhibitions, together with buildings, statues, poems, novels. . . . But all this is but the smallest part of the art by which we communicate with each other in life. All human life is filled with works of art of every kind - from cradlesong, jest, mimicry, the ornamentation of houses, dress, and utensils, up to church services, buildings, monuments, and triumphal processions. It is all artistic activity. So that by art, in the limited sense of the word, we do not mean all human activity transmitting feelings, but only that part which we for some reason select from it and to which we attach special importance. 18. This special importance has always been given by all men to that part of this activity which transmits feelings flowing from their religious perception, and this small part of art they have specifically called art, attaching to it the full meaning of the word. 19. That was how man of old -- Socrates, Plato, and Aristotle - looked on art. Thus did the Hebrew prophets and the ancient Christians regard art; thus it was, and still is, understood by the Mohammedans, and thus it still is understood by religious folk among our own peasantry. 20. Some teachers of mankind - as Plato in his Republic and people such as the primitive Christians, the strict Mohammedans, and the Buddhists -- have gone so far as to repudiate all art. 21. People viewing art in this way (in contradiction to the prevalent view of today which regards any art as good if only it affords pleasure) considered, and consider, that art (as contrasted with speech, which need not be listened to) is so highly dangerous in its power to infect people against their wills that mankind will lose far less by banishing all art than by tolerating each and every art. 22. Evidently such people were wrong in repudiating all art, for they denied that which cannot be denied - one of the indispensable means of communication, without which mankind could not exist. But not less wrong are the people of civilized European society of our class and day in favoring any art if it but serves beauty, i.e., gives people pleasure. 23. Formerly people feared lest among the works of art there might chance to be some causing corruption, and they prohibited art altogether. Now they only fear lest they should be deprived of any enjoyment art can afford, and patronize any art. And I think the last error is much grosser than the first and that its consequences are far more harmful. CHAPTER FIFTEEN 24. Art, in our society, has been so perverted that not only has bad art come to be considered good, but even the very perception of what art really is has been lost. In order to be able to speak about the art of our society, it is, therefore, first of all necessary to distinguish art from counterfeit art. 25. There is one indubitable indication distinguishing real art from its counterfeit, namely, the infectiousness of art. If a man, without exercising effort and without altering his standpoint on reading, hearing, or seeing another man's work, experiences a mental condition which unites him with that man and with other people who also partake of that work of art, then the object evoking that condition is a work of art. And however poetical, realistic, effectful, or interesting a work may be, it is not a work of art if it does not evoke that feeling (quite distinct from all other feelings) of joy and of spiritual union with another (the author) and with others (those who are also infected by it). 26. It is true that this indication is an internal one, and that there are people who have forgotten what the action of real art is, who expect something else form art (in our society the great majority are in this state), and that therefore such people may mistake for this aesthetic feeling the feeling of diversion and a certain excitement which they receive from counterfeits of art. But though it is impossible to undeceive these people, just as it is impossible to convince a man suffering from "Daltonism" [a type of color blindness] that green is not red, yet, for all that, this indication remains perfectly definite to those whose feeling for art is neither perverted nor atrophied, and it clearly distinguishes the feeling produced by art from all other feelings. 27. The chief peculiarity of this feeling is that the receiver of a true artistic impression is so united to the artist that he feels as if the work were his own and not someone else's - as if what it expresses were just what he had long been wishing to express. A real work of art destroys, in the consciousness of the receiver, the separation between himself and the artist - not that alone, but also between himself and all whose minds receive this work of art. In this freeing of our personality from its separation and isolation, in this uniting of it with others, lies the chief characteristic and the great attractive force of art. 28. If a man is infected by the author's condition of soul, if he feels this emotion and this union with others, then the object which has effected this is art; but if there be no such infection, if there be not this union with the author and with others who are moved by the same work - then it is not art. And not only is infection a sure sign of art, but the degree of infectiousness is also the sole measure of excellence in art. 29. The stronger the infection, the better is the art as art, speaking now apart from its subject matter, i.e., not considering the quality of the feelings it transmits. 30. And the degree of the infectiousness of art depends on three conditions: On the greater or lesser individuality of the feeling transmitted; on the greater or lesser clearness with which the feeling is transmitted; on the sincerity of the artist, i.e., on the greater or lesser force with which the artist himself feels the emotion he transmits. 31. The more individual the feeling transmitted the more strongly does it act on the receiver; the more individual the state of soul into which he is transferred, the more pleasure does the receiver obtain, and therefore the more readily and strongly does he join in it. 32. The clearness of expression assists infection because the receiver, who mingles in consciousness with the author, is the better satisfied the more clearly the feeling is transmitted, which, as it seems to him, he has long known and felt, and for which he has only now found expression. 33. But most of all is the degree of infectiousness of art increased by the degree of sincerity in the artist. As soon as the spectator, hearer, or reader feels that the artist is infected by his own production, and writes, sings, or plays for himself, and not merely to act on others, this mental condition of the artist infects the receiver; and contrariwise, as soon as the spectator, reader, or hearer feels that the author is not writing, singing, or playing for his own satisfaction - does not himself feel what he wishes to express - but is doing it for him, the receiver, a resistance immediately springs up, and the most individual and the newest feelings and the cleverest technique not only fail to produce any infection but actually repel. 34. I have mentioned three conditions of contagiousness in art, but they may be all summed up into one, the last, sincerity, i.e., that the artist should be impelled by an inner need to express his feeling. That condition includes the first; for if the artist is sincere he will express the feeling as he experienced it. And as each man is different from everyone else, his feeling will be individual for everyone else; and the more individual it is - the more the artist has drawn it from the depths of his nature - the more sympathetic and sincere will it be. And this same sincerity will impel the artist to find a clear expression of the feeling which he wishes to transmit. 35. Therefore this third condition - sincerity - is the most important of the three. It is always complied with in peasant art, and this explains why such art always acts so powerfully; but it is a condition almost entirely absent from our upper-class art, which is continually produced by artists actuated by personal aims of covetousness or vanity. 36. Such are the three conditions which divide art from its counterfeits, and which also decide the quality of every work of art apart from its subject matter. 37. The absence of any one of these conditions excludes a work form the category of art and relegates it to that of art's counterfeits. If the work does not transmit the artist's peculiarity of feeling and is therefore not individual, if it is unintelligibly expressed, or if it has not proceeded from the author's inner need for expression - it is not a work of art. If all these conditions are present, even in the smallest degree, then the work, even if a weak one, is yet a work of art. 38. The presence in various degrees of these three conditions - individuality, clearness, and sincerity - decides the merit of a work of art as art, apart from subject matter. All works of art take rank of merit according to the degree in which they fulfill the first, the second, and the third of these conditions. In one the individuality of the feeling transmitted may predominate; in another, clearness of expression; in a third, sincerity; while a fourth may have sincerity and individuality but be deficient in clearness; a fifth, individuality and clearness but less sincerity; and so forth, in all possible degrees and combinations. 39. Thus is art divided from that which is not art, and thus is the quality of art as art decided, independently of its subject matter, i.e., apart from whether the feelings it transmits are good or bad. 40. But how are we to define good and bad art with reference to its subject matter? 551d11cf1ff62a624b5ad3c1a5205c16f72f6127 0 172 191 2006-04-15T03:29:48Z Colin Kaminski 0 /* What is Art? */ wikitext text/x-wiki ==What is Art?== This is the age old question artists and critics have bantered around since before writing. Leo Tolstoy wrote an essay about it called [[What is Art?]]. "A large part of the beauty of a picture arises from the struggle which an artist wages with his limited medium." - ''Henri Matisse'' "Art is a man made object that is created to release an emotion from the artist and to invoke an emotion in a viewer." - ''Colin Kaminski'' A very informative treatment can be found in Maragret Benyon's [http://www.holonet.khm.de/benyonarchive/writings/gram.htm Holography as Art] ==The Hologenic Object== ==Composition== ==Lighting a Hologram== ==Fitting a Hologram into Your Decor== 795e43a762410d45d545577d6b75cabaef54a284 0 451 1052 2006-04-15T03:38:45Z Colin Kaminski 0 wikitext text/x-wiki ==Lens Equations== ==Ray Tracing== ==Images== ===Real Images=== ===Imaginary Images=== ===Orthoscopic Images=== ===Psuedoscopic Images=== ==Spatial Filter Theory== [[Optics_Aberrations]] 4a91fbae222d8b3816f9dc561185a263b927301c 6 11 871 11 2006-04-15T19:51:55Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 84 785 84 2006-04-15T20:27:25Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 151 571 151 2006-04-15T20:54:05Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 139 539 139 2006-04-16T15:38:58Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 511 1172 2006-04-16T22:51:03Z Colin Kaminski 0 Usagin Article moved to Sogokon Article wikitext text/x-wiki '''SOGOKON' A. B.''' '''LIPPMANN PHOTOGRAPH''' ON THE LAYERS OF THE BICHROMIZED GELATIN Are investigated the spectral characteristics of the Lippmann images, obtained on the layers of the bichromized gelatin (BKHZH). It is shown that the color of image depends not only on the wavelength of emission, but also on its intensity. This is connected with the heterogeneous swelling of gelatin and with a change of its structure in the nonirradiated sections with the rapid dehydration. The uncommon properties of Lippmann photographs on BKHZH can be used for preparing the selective mirrors, for mapping of graphic information, and also for registration and image processing. Is known [1] the method of obtaining the colored images, based on the registration of standing waves in the volume of thick transparent photographic emulsion. The period of the registered interference structure is unambiguously connected with the wavelength of that falling to the layer of emission, which ensures the correct color reproduction of the photographed image with the illumination by its white emission. Because of the great technical difficulties in its time this method did not obtain wide application. The development of holography led to the creation of the fundamentally new technique of experiment and new recording media. Appeared communications about the record of Lippmann photographs on the contemporary emulsions of the type LOI-2 [ 2,3 ] and on the layers of the bichromized gelatin (BKHZH) [ 4,5 ]. Purpose of this work - study of the special features of the Lippmann photographs, obtained on the layers BKHZH, the mechanism of shaping of images and possibilities of their practical application. '''Procedure and the results of the experiment''' For the preparation is layer BKHZH the basis it is undertaken the method Lina [6]. The holographic plates Of pe-2 and LOI-2 they fixed in the acid fixative, washed in the running water and dried at room temperature. The sensitization of the dried plates was conducted directly before the exhibition. For this plate was immersed on 5-15 min in 1-5%- ache the solution of dichromate of ammonium and after its runoff dried in the jet of hot air or in the cabinet drier at a temperature 100-150°. Duration of drying 3-5 min. [[Image:LippmannFig1.jpg]] Fig. 1. Installation diagram for the contact printing Lippmann photographs; 1 - luminous source (laser or mercury-vapor lamp), 2 - lens, 3 - negative, 4 - layer BKHZH, 5 - the mirror The installation diagram for the printing of Lippmann photographs is given in Fig. 1. They direct the extended laser beam to the negative, located before the recording medium, the passed emission is reflected from the flat mirror and, being extended in the opposite direction, is formed in the volume of the recording medium the standing wave, whose amplitude depends on the transmission of negative. As the radiation sources were used the lasers LPM-YY (442) and LIE -21 (337 nm) and mercury-vapor lamp DRSH-2SHCH0 (365, 436 nm). Furthermore, by means of the usual photographic enlarger was achieved the direct projection printing of enlarged images. The regime of working the plates exposed practically was differed in no way from the regime of working BKHZH for obtaining the holograms [ 7 ]. The images, obtained employing the procedure given above, have a number of interesting properties. With the examination of image in the reflected light (a subnormal incidence in the light) different sections of image depending on the density of initial negative acquire different color. Under the transparent sections is obtained the image of dark-blue color, while under the opaque - red. The semitones of negative are transferred by nuances within the limits from the orange to the green. Hence it is possible to draw the conclusion that the period of the interference structure, fixed in the layer BKHZH, depends both on the wavelength of emission and on its intensity. If we arrange Lippmann imprint on the sheet of black paper and to examine at large angle, then usual black and white image is observed. Under the transparent sections of the negative of gelatin it remains transparent, while under the opaque acquires milk-white tone. In this case the image is constructed not due to the luminous absorption, but due to its scattering, which resembles the properties of images on the vesicular materials [8]. For investigating the dependence of the color of image on the exposure level on one plate they achieved a number of exposures by the uniform collimated laser beam or photographed the image of sensitometric wedge, and then the spectra of the transmission of the obtained images were measured. [[Image:LippmannFig2.jpg]] Fig. 2. Characteristics of Lippmann the image: and, g - dependence of the spectra of the transmission of the images from the exposure level with the record by the emission heliumcadmium (442 nm) and nitric (337 nm) lasers; b and d - dependence of the density of image on the exposure for the same wavelengths; C - the dependence of the color of the image from the logarithm of exposure (curve 1 - 442, curve 2 - 337 nm); e - dependence of the half-width of the spectra of the transmission of the images from the exposure (1 - 442, 2 -337 nm) Fig. 2 depicts the spectral characteristics of the images, obtained on the plates Of pe-2, sensitized by the 1%- by the solution of dichromate of ammonium during the exhibition by the emission of lasers LPM-YY (Fig. 2, A) LIE -21 (Fig. 2, g). From the analysis of spectra follows that depending on exposure level the width of reflection spectra (Fig. 2,e) changes, the wavelength of the maximum of reflection (Fig. 2, c), and also the density of image (Fig. 2, b, d). It should be noted that the wavelength of the maximum of reflection with the long exposures does not correspond to the wavelength of the emission of record. This is connected with the fact that in the process of treating the layer an increase in the period of interference structure occurs. The wavelength of the maximum of reflection linearly depends on the logarithm of exposure (Fig. 2, c), which gives the possibility to write down [[Image:LippmannEq1.gif]] (1) where - the wavelength of the maximum of reflection with the high energy of exposure (wavelength of saturation), H - energy of exposure, k - constant of proportionality, which can be interpreted as the coefficient of the color contrast. With the conversion of the color of image occurs a change in its density (Fig. 2, b, d). These dependences are analogous to the characteristic curve of blackening of the usual recording media. However, the photographic latitude of linear section is considerably less, and in the field of the long exposures is observed the especially large spread of experimental points, which it is not possible to explain by error of measurements. It is possible to assume that the dependence of image in the region of saturation bears the oscillitory nature, for example, as shown in Fig. 2, d. '''Mechanism of the formation of the images''' In the process of the preparation of plates for the sensitization they prolonged time (about 1 h) find in the water. As a result of this gelatin it swells, long protein molecules untwist and they attempt to form the linear arrays. To molecules, which are been located on surface layer, this succeeds to the larger degree than for molecules, which are located in the depth, since they to a lesser degree experience the resistance of adjacent molecules. In the razbukhshem layer is obtained the heterogeneous tanning, which grows from surface layer to the base layer. The surface molecules of gelatin, which formed the linear arrays, no longer can accomplish work, they occupied energetically advantageous position, while molecules, which are located in the depth of layer, they have a certain reserve of potential energy, since interaction of some with others and with the molecules of tanning matter does not make possible for them to be erected into the linear arrays. Tanning can be determined by value, to the inversely proportional work, accomplished by molecules with the working in the water. Layer is not tanned, if molecules realize entire stored potential energy, and it is tanned, if potential energy with the working in the water does not realize. The potential distribution energy along the thickness of the razbukhshego layer can be schematically presented, as shown in Fig. 3, A. Let us examine the processes, proceeding with swelling of those exposed it is layer. In this case we consider that the photochemical transformations Cr(.VI) into S.r(.III) in the gelatin occur in accordance with the model, described in the work [ 9 ]. The number of photos-seam between the molecules, which were being formed in the antinodes of standing wave, is small with low energies of exposure, summary binding energy between them is also small, and the potential distribution energy of the molecules of the swollen layer takes the form, shown in Fig. 3, b. furthermore, with the prolonged working in the water together with swelling of layer in the knots of standing wave can occur the local dissolution of gelatin, i.e. the hydrated molecules acquire relative freedom, changing the structure of gelatin, but they cannot leave layer because of the tanned sections in the antinodes. In the works [ 10,11 ] it is shown that the structure of gelatin changes both with working of layer in the water and in the process of drying. Therefore with the working by isopropanol a change in the structure of gelatin in the knots and the antinodes occurs differently, i.e. with the rapid loss of water of molecule they do not manage to return to the initial state and they are forced to form the new molecular network, different from that, which is obtained with usual gel-NII - Scientific Research Institute or slow drying. In the knots of standing wave gelatin density decreases due to an increase in the volume of layer, while in the antinodes it increases due to structure change under the action of that forming Of s.r(.III). As a result of gelatin the elasticity loses, and in the layer the increased period of interference structure is fixed. With an increase in the exposure grows modulation of potential energy of the razbukhshego layer. The number of constant-phase surfaces, recorded in the layer, increases (Fig. 3, in, g, d), the width of reflection spectra and displacement into the red region decrease, and diffraction effectiveness rises. By a change in the structure of gelatin it is possible to explain the formation of black and white image. The destructured sections strongly scatter light, which gives milk-white form to them. '''Consideration of the results''' Uncommon properties of Lippmann photographs on the layers BKHZH can be used for preparing the selective mirrors, for obtaining the pseudo-colored slides from the black and white negatives, for registration and image processing. The possibility of using the Lippmann photographs as the selective mirrors directly follows from Fig. 2. The wavelength of reflection and half-width depend on exposure level. In this case the reflection coefficient attains 99%, which makes it possible to use such mirrors in the resonators of lasers, in the Fabri-Perot interferometers, and also as the beam splitters in the holographic devices. The cost of them is considerably lower than interference dielectric mirrors, and in this case is a possibility of preparing the mirrors of practically any sizes and creation of any distribution of spectral characteristics in the plane of mirror. [[Image:LippmannFig3.jpg]] Fig. 3. Diagram, which elucidates the dependence of the period of the interference structure from the exposure level: and - the distribution of the tanning in the razbukhshem unexposed layer; b, in, g, d - modulation of the tanning in the razbukhshem layer depending on the exposure The pseudo-colored slides, obtained from the black and white negatives, can be used for mapping of graphic information, for example diagrams, tables, graphs. Slides can be demonstrated both in the transmitted light by usual kadroproyektorom and in that reflected with the application of an epidiascope. The second version should be given preference, since with this more fully is used color range and is reached higher high-contrast image. With the printing from the black and white negatives the value [[Image:LippmannEq2.gif]] and [[Image:LippmannEq3.gif]] in equation (1) can be represented in the form [[Image:LippmannEq4.gif]] and [[Image:LippmannEq5.gif]] where - the intensity of light, which falls to the negative, the smallest density of negative (density of veil), density of image, time of exhibition. After substituting these values in (1), we will obtain [[Image:LippmannEq6.gif]] whence it follows that a change in the color in the Lippmann photograph is linearly connected with the density of negative. Recently increasingly more frequently is used the idea of complex spatial distributions of different physical quantities by means of the conditional it is color, for example, with digital processing of images [ 12 ]. To Lippmann photographs on BKHZH this property is inherent by their nature itself. In this case Lippmann "painting" has the advantage that the obtained image can be subjected to further optical working. Examining the pseudo-colored image through the light filter with the passband [[Image:LippmannEq7.gif]], we will observe the details of initial image, which are located in the density range [[Image:LippmannEq8.gif]]. By a change in the wavelength of light filter it is possible to separate the image details interesting, and by changing its half-width - range of densities interesting. If the image, observed through the interference light filter, photographed on the contrasting photographic material, then it is possible to obtain the images of the lines of identical density - equidensities. For the illustration is carry ouied processing the image of planet Jupiter. For this from the astro-negative they printed image with an increase by the layer BKHZH. The obtained image they photographed through the interference light filter with [[Image:LippmannEq9.gif]] = 640 nm and [[Image:LippmannEq10.gif]]= 90A. Fig. 4, and depicts the photograph of initial image, while on Fig. 4, b, C - to a series of photographs with the different angles of the slope of interference light filter, i.e. with the different [[Image:LippmannEq9.gif]] and [[Image:LippmannEq10.gif]]. It is evident that even under the conditions for the incorrectly set experiment (reconstruction of the wavelength of light filter was achieved via its inclination) on the obtained images it is possible to reveal more interesting details, than on the initial negative. [[Image:LippmannFig4.jpg]] Fig. 4. Isolation of equidensities on the image of planet Jupiter: and - the imprint of siskhodnogo astro-negative; b - photograph of the Lippmann image, obtained with the interference light filter with the different angles of its inclination in the reflected light; C - the same, but in the transmitted light However, with the two-stage process unavoidably are shown distortions and noise, which appear during the first stage of registration. The granularity of images on Fig. 4, b is caused by the granularity of the material, on which is registered initial negative. Therefore the considerably larger volume of information can be extracted with processing of the Lippmann images, obtained with the direct registration. However, sufficiently small sensitivity it is layer FOR BKHZH it does not make possible to directly record the images of other astros-object, except the sun. The direct registration of Lippmann images possibly in biology. In this case the emission of lamp DRSH-2SHCH0 it is completely sufficient for obtaining the images with increase in 30-100x. Thus, the Lippmann photographs, obtained on the layers BKHZH with the use of sources of monochromatic light, have properties, substantially different from the properties of usual Lippmann photographs. This is connected with the special features of the recording medium: the period of the fixed interference structure depends not only on the wavelength of incident radiation, but also on its intensity. As a result the possibility of the single-valued conversion of the intensity of light in the color appears. Simplicity of the diagram of obtaining Lippmann photographs, possibility of using the sources with the small length of coherence and high diffraction effectiveness of images open the great possibilities of the practical application of this method. In conclusion the author considers as his pleasant duty to express appreciation To v. p. sherstyuk and L. ye. mazur for the valuable considerations, in. By a. kaminskoy and By l. ye. nikishinoy for help in conducting of spectrophotometric measurements and V. n. dudinova - for the kindly furnished astro-negatives. '''LITERATURE''' *1. Lippmann G S. R// Acad. Sci. 1891. V. 112. P 274. *2. Kostylev G. d. //Pis'ma in ZHTF 1976. Vol. 2. Of iss. 23. S. 1086. *3. Kostylev G. d., Ivanenko L. i.// the theses of dokl. IV All-Union conf. "photometry and its metrological guarantee". M., 1982. S. 119. *4. Sogokon' A. V.// the theses of dokl. IV All-Union conf. "non and uncommon fo- tograficheskiye processes". Blackcap, 1984. Vol. 1 of h. 2. S. 251. *5. Sogokon' A. b.// the theses of dokl. II All-Union conf. the "forming of optical image and the methods of its working". Kishinev, 1985. Vol. 1. S. 125. *6. Lin L n.// Appl. Opt. 1969. V 8. № 5. P 963. *7. Sjolinder S// Photogr. Sci. And Eng. 1984. V 28. № 5. P 180. *8. Nagornyy V. i., Chibisova N. p. //ufn. 1978. Vol. 19. S. 32. *9. Sherstyuk V. p., Dilung I. I. In the book: Fundamental bases of the optical of pamya- TI and medium. Kiev: Vishcha shk. 1982. Iss. 13. S. 33. *10. Levi S. m., Suchkova O. m., Suvorin V. V.// the jour. of nauch. and appl. photo- and kinema of tografii. 1984. Vol. 29. № 4. S. 252. *11. Murzinov A. V., Moiseyeva G. V., Stryukova e. g. and other// theses of the report republic of se- of minara "applied holography". Kiev, 1984. S. 49. *12. Usikov A. 4., Babichev A. A., Yegorov a. d., etc.// to conduct. AN OF UKRCSSR - UKRAINIAN SSR. 1977. № 10. S. 47. Kharkov state university im. a. M. of Gor'kiy 25c7666842e7392e25efaaaf5cbb3400fceb0244 0 580 1310 2006-04-16T22:51:03Z Colin Kaminski 0 Usagin Article moved to Sogokon Article: Wrong Author! wikitext text/x-wiki #redirect [[Sogokon Article]] 93c6065a2d9de963d758ae074e9210b85973895a 0 275 397 2006-04-17T14:10:59Z Colin Kaminski 0 wikitext text/x-wiki While holography is a fairly safe activity it is important to understand the materials we are dealing with and treat them with respect. Below we have compiled so information that a holographer will find usefull. It is always growing and is by no means exhaustive. '''[[Laser Safety]].''' Safe practices and some potential hazards of Lasers. '''[[Chemical Safety]].''' Safe practices and some potential hazards of chemical handling. '''[[Power Tool Safety]].''' You can make anything you want but keep your eyes and fingers! '''[[Books]].''' 0fc416ad1fbe7c3064d58cce53ba8519be58c698 0 458 1066 2006-04-18T03:02:19Z Phil Edelbrock 0 wikitext text/x-wiki http://secure.netroedge.com/~phil/IRs/DSCN1472.jpg (high speed near-infrared photo from a digital camera (Nikon Coolpix 995) I modified just minutes before this photo was taken. I was staring in amazement at the LCD display while I snapped this picture. [http://holographyforum.org/phpBB2/viewtopic.php?t=2043 more on this]) I'm a scientist, engineer, and a wanna be entrepreneur. I was a Linux kernel developer for a while ([http://secure.netroedge.com/~lm78/ the project] still runs strong with the help of others), I have a degree in both computer science and computer engineering (the first is mostly software, the other hardware). I'm a weak lab sort. I'm impatient. For example, I hate movies, they take too long. So I spend a vast majority of my waking hours doing work on a computer (I prefer Linux for work, I support Macs at work, and have a few Windows machines for games and evil proprietary needs). I'm the IT, IS, DBA, telephone, sometimes backend web programmer, and general tech support guy at a small advertising/graphic design agency. As far as holography goes, I got amazed with holograms and lasers in middle and high school. At the time, though, it was expensive, very vague, and sometimes dangerous. Alas, I was completely unsuccessful at creating a hologram, and most likely I found out much later due to some useless Kodak film that was pushed on to me. My doubts lifted when I made a hologram in an unused bathroom at high school during electronics class (the closest thing to a hands-on science class at the time) using Agfa film (which at the time seemed to be getting very hard to get). Later, it was only after finding out about the Holography Forum that I got back into making, buying, and helping those making holograms (where I can) that I got back into the hobby. I'm proud to help Colin, Michael, John, and the many others who work hard to make holography less a monopoly, less scary, less mystical, and simply fun and creative. (PS- I have a problem with using too many parenthesis (as if you didn't notice!), but deal with it! This is my space! ;') [[http://www.holographyforum.org/HoloWiki/index.php?title=Talk:Phil_Edelbrock&action=edit Have a comment? Click here.]] b369b63998b6e7936230988f6be9e6eb7d09479b 0 428 1006 2006-04-19T14:18:08Z Colin Kaminski 0 wikitext text/x-wiki ====A Machined Film Holder==== [[Image:FilmHolder.gif]] by: Colin Kaminski '''4" x 5" Film Holder''' after Dinish and Joy Padyir's. This film holder is a copy of one Dinesh and Joy were using when I was there. I made it from 3/4" square aluminum bar. (This is not quite how I made it but I am going to include how I would make it again when I make a second one this week.) Take a 12" or so section of 3/4" aluminum bar and set a table saw to cut .25" deep. Set the fence .125" from the blade (make sure the fence is parallel to the blade!) Run the piece of aluminum through. (Use two push sticks so you don't get your hands anywhere near the blade. Also a feather board or two would be of use but I did not have any handy.) Then move the fence over about .035 inches or however wide you want the slot. You can make the slot wide enough to accommodate 2 plates and film if you wish. Then hack saw it to 4.25" or so. (Where the table saw blade exited the part you will notice the slot is wider than the rest of the part. This is because the blade started to ring upon exit and you should make sure to cut off this end.) Set up your cross cut saw on your table saw very square then taking about .030 inches in a pass trim both ends until the ends are clean, square and the piece is exactly 4". Cut another piece to 6+ inches and clean up the ends on the table saw till it is square and 6" long. Measure down the 4" pieces 1" from each end and make a line. Measure from the lip .125" and make a line. Where these lines intersect, use a drill press and drill a #36 hole through to the channel. (Marking the hole with a spotting dril is handy to keep the wholde from drifting. At least make sure you have as little of the drill bit sticking out of the chuck as posible and mark the spot with a punch.) Tap to #6 32 tpi. These will be the plate holder screws. (Note: tap from the small side for a reflection plate holder and from the thick side for a transmission holder, or you can make two slots in the same plate holder.) Mark the two 4" pieces on the ends in the center. (This operation will make the parts "Handed" so make sure to pick opposite ends for this mark.) Drill in a drill press a #F hole about 1/2" deep. Tap to 5/6" 18 tpi. Measure .375" up and over on the 6" pieces (on the 6" face) and make a mark at each end. Drill through with a 5/16" drill bit. (If you miss this hole or the holes in the ends you can make this hole larger so you can get the parts to align.) In the center of the bottom of the 4" pieces (away from the slots) drill a #7 hole .425" deep. Tap with a 1/4 20 tpi tap. In the center of the 6" piece, on the same face as the holes, drill a #7 hole .425 or so deep and tap to 1/4" 20 tpi. These will be the mounting holes. Clean up the corners with a file, and clean up the holes with a countersink tool. Spray paint with Krylon Ultra flat black paint. Bolt channels to the bas with 2-5/16", 18 tpi, 1" long Allen bolts. Put 4 #6 32 tpi Allen bolts into the channels but first file the ends flat with a 6" mill smooth file. The length should be chosen so it sticks out about .25" when holding a plate. Put 3 1/4", 20 tpi, .75" long Allen set screws into the tapped holes. These now will fit any 1/4" mounting rod. Spray paint with Krylon Ultra flat black paint. My total time invested was three hours. A nice touch would be to bevel the front side of the plate holder to 45 deg. You can easily do this with a router and a bearing bit. What you say? Cut aluminum with wood working tools? The truth is it works very well and I have been doing it for years. It works much better than many woods and it is much faster than milling. I once purchased a 9 HP pin router from Boeing that was used to rout airplane parts. We used it to make electric guitar bodies. If you were going to use your table saw a lot for making aluminum parts I would use a ATB grind 60 tooth blade with large blade stiffeners. 3bfa786fa94a0c5a6ddaa4a3b362979c856c775e 0 169 185 2006-04-19T14:19:52Z Colin Kaminski 0 wikitext text/x-wiki By: John Pecorra Well, there has been some talk about tables and plateholders so I thought I might post my plateholder design. It is original and I like it better then any plateholder I have ever used or seen. It allows from a 4" to a 20" format. It is quick and easy to load, even in the dark. It is very stable. I tried to put notes in the drawing to describe how it works but feel free to question anything. Also feel free to use the design if you want. It is all steel construction. The vertical poles are solid 1 1/2" rods. The angle iron on the top has holes cut out for the poles but the holes are slightly larger. There is no need to have the holes and rods within close tollerances. The top angle iron simply rests on the plate via the 2 sets of 2 screws as described. Then the thumbscrew is turned to place a slight bit of pressure from the angle iron to the pole to take the "ting' out but no stressing is involved as the large holes in the angle iron allow the angle iron to float freely, tilting to and away from the pole with the turn of the screw. The design of the top shades the very top part of the plate so nothing else is needed to keep the light from entering the edge of the plate. Another nice feature is there is room to squeeze light very close to the plate on the inside or outside of the pole depending on acutal film plate size. [[Image:AngleIronFilmHolder.jpg]] fd43596e97af92e42c70bb3ebc8212d2107107ea 6 106 443 106 2006-04-19T14:20:25Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 522 1194 2006-04-20T05:33:22Z Colin Kaminski 0 /* Cross cutting */ wikitext text/x-wiki ==Setting up a table saw== *Set the blade to full depth. *Measure the blade to table angle with a square. *Adjust the blade angle to square. *Set the blade depth. If making a through cut you want the blade to not be higher than 1 tooth above the work. *Adjust the fence to position. Very carefully measure from the edge of a front tooth to the fence and then measure the tooth on the back edge the blade the fence. Adjust the fence until they are equal and the fence is square. *Setup the miter carage ==Choosing the proper blade== ==Cutting Aluminum== ==Cross cutting== ===Cross Cutting with a Fence=== ==Safety== 735609e86c695544ae6fcbb42d5febc20e22eab8 0 434 1018 2006-04-21T01:41:14Z Colin Kaminski 0 wikitext text/x-wiki Under construction - please feel free to add... The best calculator available on the net is the Google search box! [http://www.google.com/help/features.html#calculator Google Math!] For example if you enter: c in furlongs/fortnight It will give you the speed of light in the most esorteric dimensions imaginable. the speed of light = 1.8026175 × 10^12 furlongs / fortnight ==Math Links== [http://mathforum.org/library/topics/basic_algebra/ Math Forum] ==Simple Trigonometry== It is helpful to read equations aloud until you have some experience with them. Here is a guide on how to pronounce different equations. * sin(θ) is read as "the sine of Theta". * cos(θ) is read as "the cosine of Theta". * tan(θ) is read as "the tangent of Theta". [[Image:TrigAngles.gif]] In a right triangle the: * sin(θ)=opposite/hypotenuse or a/c * cos(θ)=adjacent/hypotenuse or b/c * tan(θ)=opposite/adjacent a/b ===Pythagorean Theorem=== a^2+b^2=c^2 - Read as a squared plus b squared equals c squared. The Pythagorean Therom is used to find an unknown side length if the other two are known in a right triangle. ===Angle Theorem=== The sum of all angles in a triangle are equal to 180 degrees. ===Examples=== With sin, cos, tan and the Pythagorean Theorem you can solve all of the sides and angles in a right triangle if any 3 parameters are known. For Example: If a=7 and b=5 then 7^2+5^2=c^2 49+25=c^2 74=c^2 sqr(74)=c 8.6=c Now we have all three sides. sin(θ)=7/8.6 sin(θ)=.814 θ=arcsin(.814) - Pronounced theta equals the arc sine of point 814. θ=54.5deg Now we have two angles (90 and 54.5): 180=90+54.5+(our missing angle) 180-90-54.5=our missing angle our missing angle = 35.5. Now we have solved all of the sides and angles of this right triangle. I choose to use Pythagorean Theorem, sin and the angle theorem but we could have used other choices. ===Simple Identities=== *tan(θ) = sin(θ) / cos(θ) = a / b *sin(-θ) = -sin(θ) *cos(-θ) = cos(θ) *tan(-θ) = -tan(θ) *sin^2(θ) + cos^2(θ) = 1 *sin(2x) = 2 sin x cos x *cos(2x) = cos^2(x) - sin^2(x) = 2 cos^2(x) - 1 = 1 - 2 sin^2(x) *tan(2x) = 2 tan(x) / (1 - tan^2(x)) *sin^2(x) = 1/2 - 1/2 cos(2x) *cos^2(x) = 1/2 + 1/2 cos(2x) *sin x - sin y = 2 sin( (x - y)/2 ) cos( (x + y)/2 ) *cos x - cos y = -2 sin( (x-y)/2 ) sin( (x + y)/2 ) ===Law of Sines=== Given Triangle abc, with angles A,B,C; a is opposite to A, b oppositite B, c opposite C: a/sin(A) = b/sin(B) = c/sin(C) ===Law of Cosines=== *c^2 = a^2 + b^2 - 2ab cos(C) *b^2 = a^2 + c^2 - 2ac cos(B) *a^2 = b^2 + c^2 - 2bc cos(A) ===Law of Tangents=== *(a - b)/(a + b) = tan 1/2(A-B) / tan 1/2(A+B) ==The Greek Alphabet== *Α - Alpha *α - Alpha Lower Case *Β - Beta *β - Beta Lower Case *Γ - Gama *γ - Gama Lower Case *Δ - Delta - Sometimes spoken as "the change in". *δ - Delta Lower Case *Ε - Epsilon *ε - Epsilon Lower Case *Ζ - Zeta *ζ - Zeta Lower Case *Η - Eta *η - Eta Lower Case *Θ - Theta *θ - Thete Lower Case - Used to represent angles. *Ι - Iota *ι - Iota Lower Case *Κ - Kappa *κ - Kappa Lower Case *Λ - Lamda *λ - Lamda Lower Case - Used to represent wavelength. *Μ - Mu *μ - Mu Lower Case *Ν - Nu *ν - Nu Lower Case *Ξ - Xi *ξ - Xi Lower Case *Ο - Omicron *ο - Omicron Lower Case *Π - Pi *π - Pi Lower Case - The diameter of a circle divided by it's diameter *Ρ - Rho *ρ - Rho Lower Case *Σ - Sigma - "The sum of" *σ - Sigma Lower Case *ς - Sigma *Τ - Tau *τ - Tau Lower Case *Υ - Upsilon *υ - Upsilon Lower Case *Φ - Phi *φ - Phi Lower Case *Χ - Chi *χ - Chi Lower Case *Ψ - Psi *ψ - Psi Lower Case *Ω - Omega *ω - Omega Lower Case 9df6bfbd3268e6495f71e30728bdb32d5ccf9fe7 0 486 1122 2006-04-21T02:06:02Z Colin Kaminski 0 /* Holography Glossary */ wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Sabattier effect''' - part positive part negative effect formed when an emulsion is briefly re-exposed to white light during development, and then allowed to continue development. Also known as pseudo-solarization. *'''Safelight''' - darkroom light of a color and intensity that will not affect light sensitized photographic materials. *'''Safety film''' - term used to describe a film with a base that is not readily inflammable. *'''Scale''' - linear relation between the size of the subject and the size of its image. *'''Scanning electron microscope''' - device used in photomicrography. *'''Schumann plate''' - plate coated with an emulsion with so little gelatin content that the silver halide grains protrude above its surface. Used for photography in the ultraviolet region. *'''Screening''' - conversion of a continuous tone image to a half-tone image. *'''Screen plate''' - plate used in early additive forms of color photography. *'''Scrim''' - lighting attachment which, when placed in front of a lamp, reduces its strength, usually by one stop, without affecting lighting quality or color. *'''Selective focusing''' - method of adjusting the lens aperture and shutter speed to give a depth of field that will limit image sharpness to a particular area of the image. *'''Selenium''' - light-sensitive substance which, when used in a barrier-layer construction, generates electrical current when exposed to light. Used in exposure meters and dry copy film. *'''Selenium cell''' - light sensitive cell used in many types of exposure meters. It generates electricity in direct proportion to the amount of light falling upon its surface. *'''Self-timer''' - mechanism for delaying the opening of the shutter for a given number of seconds after the release has been operated. *'''Self toning paper''' - obsolete silver chloride paper used for contact printing in daylight. *'''Sensitive material''' - in photography, refers to materials that react to the actinic power of light. *'''Sensitivity''' - degree of response of a photographic emulsion to exposure to light. *'''Sensitometry''' - scientific study of the response of photographic materials to exposure and development. It establishes emulsion speeds and recommended development and processing times. *'''Separation images''' - technique of producing an image by combining photographs produced on a material or using equipment which is sensitive to one region of the visible spectrum. *'''Separation negatives''' - black & white negatives, usually prepared in lots of three or four, which have been taken through filters which analyze the color composition of an original in terms of blue, green and red. They are used particularly in photomechanical color printing and dye transfer printing processes. *'''Shadow detail''' - details visible in areas that are darkest in the subject. *'''Shadows''' - darkest areas in a photographic print. *'''Shellac''' - natural resin with a low melting point. It is mainly used on dry mounting tissue. *'''Shelf life''' - length of time unused material or chemicals will remain fresh. *'''Shutter''' - mechanical system used to control the time that light is allowed to act on the sensitive emulsion. *'''Shutter speed''' - action of the shutter that controls the duration of an exposure. The faster the speed the shorter the exposure. Shutter speed settings are given in the fraction of a second. Each setting is half the duration of the preceding one in a constant scale, marked on the shutter speed dial or ring. *'''Side lighting''' - light striking the subject from the side relative to the position of the camera. It produces shadows and highlights to create modeling on the subject. *'''Silhouette''' - photographic image in which the subject is seen as a solid black shape against a light background. *'''Silicon release paper''' - thin, heat resistant interleaving paper, used between a photographic print and textured material in a heated press. It allows remolding of the print surface yet prevents the two materials from sticking together. *'''Silk print''' - image made on silk by means of the diazo or dye printing methods. *'''Silkscreen''' - method of applying inks to paper or similar materials using a nylon stencil produced by photographic means. *'''Silver halides''' - light sensitive crystals used in photographic emulsions, i.e. silver bromide, silver chloride and silver iodide. The change from white to black metallic silver when exposed to light. *'''Silver nitrate''' - chemical combination of silver and nitric acid. It is used in intensifiers, physical developers and photographic emulsions manufacture. *'''Silver reclamation''' - system for recovering silver from exhausted solutions. *'''Silver recovery''' - system of reclaiming silver from exhausted solutions. *'''Silver salts''' - compounds of silver. *'''Simultaneous contrast''' - effect that adjacent color hues have upon each other. *'''Sizing''' - very dilute, gluey substance used to prepare surfaces for coating by filling in pores and giving even absorbance. *'''Sky filter''' - outdated term for a filter which has a graduated density across its surface. *'''Slit shutter''' - narrow vertical slit either just in front of the emulsion or at a similar distance in front of the lens. Film is wound through the camera at a constant speed giving one long image along the length of the film. *'''Slow sync''' - flash technique for using the flash at a slow shutter speed. Flash shooting in dim light or at night at a fast shutter speed often results in a flash-illuminated subject against a dark background. Using a slower shutter speed with the flash brings out the background details in the picture. *'''Snapshot''' - term once used to describe a photograph taken with the I (instantaneous) setting on cameras. The term originally came from rifle shooting, when little or no time is allowed for aiming. *'''Snoot''' - cone shaped shield used on spotlights to direct a cone of light over a small area. *'''Sodium bichromate''' - chemical used in intensifiers, toners and bleaches. *'''Sodium bisulfite''' - chemical used in fixing baths as an acidifying agent. *'''Sodium carbonate''' - alkaline accelerator used in many general purpose and print developers. *'''Sodium chloride''' - used in some bleaches and reducers. *'''Sodium hexametaphosphate''' - water softener. *'''Sodium hydrosulfite''' - used as a fogging agent in reversal processing. *'''Sodium hydroxide''' - highly active alkaline accelerator used in conjunction with hydroquinone to produce high contrast developers. *'''Sodium metabisulfite''' - used as an acidifying agent in acid fixing baths. *'''Sodium sulfide'''- chemical used in sulfide (sepia) toning. *'''Sodium sulfite''' - chemical commonly used as a preservative in many developing solutions. *'''Sodium thiocyanate''' - alternative to potassium thiocyanate and is used as a silver solvent in physical and ultra-fine grain formulae. *'''Sodium thiosulfate''' - chemical used in many fixing solutions. It converts unused halides to a soluble complex which can be removed by washing. *'''Soft developer''' - paper developer that can be used alone or in combination with other developers (two-bath development) to achieve more subtle contrast control. *'''Soft focus''' - definition of a diffused image. This can be achieved at the camera or enlarging stage. *'''Soft focus lens''' - lens, uncorrected for spherical aberrations, used to produce a soft focus effect. *'''Solarization''' - reversal or partial reversal of tones in a photographic image caused by vast amounts of over-exposure. It is often inaccurately used to describe the partial reversal effect caused by fogging photographic material with light, which is actually the Sabattier effect. *'''Solubility''' - in general terms is the ease with which a solid will mix homogeneously with water to provide a chemical solution. *'''Spacing bracket''' - device used to position the camera at the right distance from the subject for the lens focus setting in closeup work. *'''Spectral sensitivity''' - relative response of a photographic emulsion to each of the colors of the spectrum, including infrared and ultraviolet. *'''Spectrum''' - usually used in reference to the visible part of the electro-magnetic spectrum, i.e. the color bands produced by diffraction, and arranged according to wavelength, when white light is passed through a prism. *'''Speed''' - sensitivity of a photographic emulsion to light. Films are given ISO or DIN numbers denoting speed characteristics. *'''Spherical aberration''' - lens fault which causes loss of image definition at the image plane. Its affects are reduced by stopping down. *'''Spool''' - bobbin like object consisting of a narrow core with flat disks on either end, around which the film is wound. *'''Spotlight''' - artificial light source using a fresnel lens, reflector, and simple focusing system to produce a strong beam of light of controllable width. *'''Spot meter''' - used to get accurate light readings of a small part of a subject. It uses a narrow angle of view to measure within limited areas. *'''Spotting''' - method of retouching. Blemishes or unwanted details are removed from negatives and prints by brush and dye or pencil. *'''Sprocket holes''' - perforations on both edges of 35mm film, which engage with the teeth of the film transport mechanism. *'''Squeegee''' - tool with rubber blades or rollers, used to squeeze water out of wet prints. *'''Stabilization''' - alternative method of fixing. Unused halides are converted to near stable compounds, insensitive to light. No washing is required. *'''Stabilizer''' - final solution often used in color processing which leaves the dyes produced by chemical development more stable and fade resistant. *'''Staining developer''' - developer, such as pyro, in which the oxidation products give extra image density by staining the gelatin. *'''Stand''' - alternative name for a tripod. *'''Static marks''' - jagged fog marks on negatives as a result of a very dry film being rewound or unwound too rapidly. *'''Step wedge''' - printed series of density increases, in regular steps from transparent to opaque. Its a method of making exposure tests when enlarging. Stereoscope - viewer which accepts pairs of stereoscopic images. *'''Stereoscopic camera''' - camera designed to take simultaneous images of the same subject from viewpoints separated by the same distance as that between the eyes. *'''Stereoscopy''' - method of creating a three dimensional effect on a two dimensional surface using a pair of images taken from slightly different viewpoints, and viewed through specially made stereo viewers. *'''Still life''' - inanimate subject, either in the studio, or outdoors, normally arranged to make full use of form, shape and lighting. *'''Stop''' - aperture of a camera or enlarging lens. *'''Stopping down''' - reducing the size of the lens aperture and thus the amount of light passing into the camera. It increases depth of field. *'''Stress marks''' - black lines on a photographic emulsion caused by friction or pressure. *'''Subbing''' - layer applied to a photographic support as a foundation for the emulsion. *'''Subject''' - person or thing photographed. *'''Subjective photography''' - interpretive image of the subject, with results influenced by the attitude of the photographer. *'''Successive color contrast''' - trick of the human eye by which the impression of a color is influenced by an immediately preceding color stimulus. *'''Sulfide toning''' - conversion of a black metallic silver image into a brown dye image. Usually known as sepia toning. *'''Sulfuric acid''' - high corrosive chemical used in reducers. *'''Supper coat''' - top coating of non-sensitized gelatin added to sensitized emulsions to form a protective layer. *'''Surface development''' - development process in which the image forms primarily on the surface of the emulsion and then penetrates deeper. *'''Surge marks''' - streaks on the image from each of the sprockets holes of 35mm film caused by excessive agitation. *'''Surrealism''' - originally an early 1920s artistic movement, now taken to indicate the production of unreal images which defy reason. *'''Swing back/front''' - term used to describe the movable lens and back panels of most view and monorail cameras. They allow manipulation of perspective and depth of field. *'''Symmetry''' - effect of an evenly balanced arrangement of visual information, such as pattern, on either side of a central division. ea920f4ca0f50707dc7483570b3e6470b45c84ef 0 518 1186 2006-04-21T02:11:51Z Colin Kaminski 0 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''T''' (Time) - shutter speed setting used for timed exposures longer than the numbered settings. The shutter opens when the release is pressed and closes when it is pressed again. Now largely super ceded by B (Bulb). *'''Tacking iron''' - heated tool used to stick part of the dry-mounting tissue to a print and its mounting board. *'''Tempering bath''' - large tank or deep tray filled with water maintained at the correct temperature for processing. Used to house tanks, drums or trays as well as containers of processing solutions. *'''Test strip''' - trial and error method of calculating exposure in photographic printing. A number of exposures are given to a strip of emulsion, over important areas of the image to help judge the correct exposure in the final print. *'''Texture''' - broadly defined as the surface character of an object. *'''Texture screen''' - transparent film or glass printed with a fine background pattern. They're interposed between the image and the paper to break up large areas of tone or for special effects. *'''T-Grain technology''' - name for Kodaks film emulsion technology used in all Kodak APS films. Uniquely shaped grains that align better than conventional silver crystals absorb and transmitting light more effectively to produce sharper images. *'''Thermography''' - recording images by means of the heat radiated from the subject. *'''"Thick" negative''' - antique term used to describe a dense negative. *'''"Thin" negative''' - antique term used to describe a negative lacking in density. *'''Time and temperature''' - controlling factors of a chemical photographic process. *'''Time exposure''' - general term for an exposure longer than can be set using the camera's fixed shutter speeds. *'''Time lapse photography''' - method of recording chemical and physical changes in a subject over a period of time by photographing it at regular intervals from the same viewpoint. *'''Timer''' - clock used to control processing. *'''Tinting''' - application of color tints, usually in the form of dyes or paints, to a photographic image to create or enhance color. *'''Tomography''' - radiographic technique used in medial photography. *'''Tone''' - refers to the strength of grays between white and black. It relates to the brightness, lightness and darkness of the subject and is determined by illumination. *'''Tone line process''' - technique used to reproduce a photographic image so that it resembles a pen and ink drawing. *'''Tone separation''' - process of reducing the tonal range of a photograph to a very restricted range. The final result has strong highlights and deep shadows with a set number of intermediate tones. Also refereed to as Posterization. *'''Tone values''' - various shades of gray between the extremes of black & white in a photographic image. *'''Toners''' - used to change the color of the photographic print by chemical baths. Through the system of bleaching and toning, the black metallic silver image is converted to a dye image. *'''Toning''' - method of soaking the print in selenium or similar chemical(s) to help give the print an overall feeling of "richness". *'''Transfer processes''' - methods of transferring a photographic image from one surface to another. *'''Transmission''' - passage of light through a transparent or translucent material. *'''Transmitted light''' - light which is passed through a transparent or translucent medium. The amount of light transmitted depends on the density of the medium through which it is passed and on the brightness of incident light source. Transmitted light is always less than incident light, but the amount of loss depends on the density of the medium. *'''Transparency''' - positive image in black and white or color, which is produced on transparent film. *'''Transparent magnetic layer''' - information storage layer built into Advanced Photo System film that enables enhanced information exchange capabilities. *'''Transposing frame''' - frame used for printing pairs of stereoscopic negatives from a two lens camera. *'''Tray development''' - any process carried out in open trays rather than using tanks or similar apparatus. *'''Trichrome Carbro Process''' - method of making assembly color prints from separation negatives, using an adaption of the carbro process. *'''Triple extension''' - camera system in which lens-image distance can be extended by as much as three times its focal length. It is particularly useful for close-up photography. *'''T stops''' - more accurate measurement of light entering a lens than "f" numbers. Whereas "f" numbers represent the ratio between measured diameter and focal length, "t" stops are based on actual light transmission at different diameters. *'''Tungsten filament''' - artificial light source using a tungsten filament contained within a glass envelope. *'''Tungsten halogen lamp''' - improved version of the normal tungsten lamp. It is much smaller and more consistent in color temperature as the glass envelope used is non-blackening. *'''Tungsten light''' - light from standard room lamps and ceiling fixtures, not fluorescent. *'''Two-bath development''' - development of negatives in two stages. Developer without alkali is followed by an alkali bath, which activates development. *'''Two-color photography''' - simple method of color photography which analyzes the spectrum into two parts instead of three, forming images which are combined with complementary colors. *'''Type A film''' - color film balanced to artificial light sources at a color temperature of 3400K. *'''Type B film''' - color film balanced to artificial light sources at a color temperature of 3200K. *'''Type D film''' - obsolete term for film balanced for daylight. *'''Two-bath development''' - development of negatives in two stages. Developer without alkali is followed by an alkali bath, which activates development. 70756d29a24ccd507768574266aa7c74bc4e39c5 0 467 1084 2006-04-22T02:03:11Z Colin Kaminski 0 wikitext text/x-wiki Using power tools saftley is a very importent step that is often overlooked in the rush to get a project together. When in doubt read the manual! More information can be found on the pages for [[Shop Basics|specific tools]]. *Wear safety glasses! (Nothing is 3-D with only one eye!) *Wear hearing protection. *Don't wear gloves with drills or drill presses. *Don't cross cut with the fence on a table saw. *Use a vice in a drill press. *Check the underside of a cut before skill sawing. *Pay attention. *Don't ever put your body at risk. Stop. Make a jig. be736f85f56ad79b134b714ee80df4243e04cfc0 0 277 401 2006-04-22T02:19:02Z Colin Kaminski 0 wikitext text/x-wiki [http://courses.media.mit.edu/2002spring/mas450/reading/chaptersPDF/index.html Steve Benton's Book Draft] is a good place to start. *[[Learning About Light]] *[[Holography Theory K-12]] *[[Advanced Mathematics for Holography]] *[[Optics Theory]] *[[Color Theory]] *[[3-D Perception]] *[[Art Theory]] *[[Table Design Theory]] *[[Math Help]] *[[Strength of Materials]] *[http://en.wikipedia.org/wiki/Periodic_table_%28standard%29 Periodic Chart] *[[Books]] acb951038f4f412b897d7c9b2b14d9a6eea8e89b 0 272 391 2006-04-29T16:05:03Z Colin Kaminski 0 wikitext text/x-wiki ===Diffraction gratings=== ===Reflection Holographic Optical Elements=== ===Transmission Holographic Optical Elements=== e6f08a62e99e20230fd40c44e33927251a76c6d3 6 109 447 109 2006-04-30T15:09:02Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 470 1090 2006-04-30T15:09:45Z Colin Kaminski 0 /* Gel Strength= */ wikitext text/x-wiki '''Gelatin''' *by Dr. Bernard Cole *Copyright - 2006 Bernard Cole - This is not Open Source Copyright *[http://www.gelatin.co.za/ Dr. Bernard Cole's Web Site] [[Image:BCole.jpg]] ===INTRODUCTION=== Gelatin is a substantially pure protein food ingredient, obtained by the thermal denaturation of collagen (1), which is the structural mainstay and most common protein in the animal kingdom. Today gelatin is usually available in granular powder form, although in Europe, sheet gelatin is still available. There are two main types of gelatin. Type A, with isoionic point of 7 to 9, is derived from collagen with exclusively acid pretreatment. Type B, with isoionic point of 4.8 to 5.2, is the result of an alkaline pretreatment of the collagen. However, gelatin is sold with a wide range of special properties, like gel strength, to suit particular applications. Gelatin (2) forms thermally reversible gels with water, and the gel melting temperature (<35°C) is below body temperature, which gives gelatin products unique organoleptic properties and flavour release. The disadvantage of gelatin is that it is derived from animal hide and bone (not from trotters as is a common perception), hence there are problems with regard to kosher and Halal status and vegetarians also have objections to its use. Competitive gelling agents like starch, alginate, pectin, agar, carrageenan etc. are all carbohydrates from vegetable sources, but their gels lack the melt in the mouth, elastic properties of gelatin gels. ===CHEMISTRY and BIOCHEMISTRY=== Gelatin is an amphoteric protein with isoionic point between 5 and 9 depending on raw material and method of manufacture. Like its parent protein, collagen (3), it is unique in that it contains 14% hydroxyproline, 16 % proline and 26 % glycine. The only other animal product containing hydroxyproline is elastin and then at a very much lower concentration, so hydroxyproline is used to determine the collagen or gelatin content of foods. In brief, the protein is made up of peptide triplets, glycine - X - Y, where X and Y can be any one of the amino acids but proline has a preference for the X position and hydroxyproline the Y position (3). Approximately 1050 amino acids produce an alpha-chain with the left-handed proline helix conformation. Collagen exists in many different forms but gelatin is only derived from sources rich in Type I collagen which contains no cystine, however, hide or skin contains some Type III collagen which can be the source of traces of the traces of cystine found in some gelatins. Although Type I collagen contains no cystine, the alpha procollagen chains excreted by the cell do contain cystine at the C terminal end of the protein which is thought to be the site of assembly of 3 alpha-chains. The three chains then spontaneously (4) coil together, zipper fashion, to form a right-handed helix. After spontaneous helix formation, cross links between chains are formed in the region of the N terminal telopeptides (globular tail portion of the chains) and then the telopeptides (containing the cystine and tyrosine of pro-collagen) are shed leaving the rod-like ca. 3150 amino acid containing triple helix . These collagen rods assemble together with a quarter-stagger to form the collagen fibre and the fibres are stabilised by further cross-links. Gelatin is the product of denaturation or disintegration of collagen. Initially the alpha-chains of collagen are held together with several different but easily reducible cross-links. As the collagen matures, so the cross-links become stabilised (3). Then as time progresses the eta-amino groups of lysine become linked to arginine by glucose molecules (Maillard reaction) to form the pentosidine type cross-links which are extremely stable (5). Hence when the alkaline processing is used on young animal skin the alkali breaks one of the initial (pyridinoline) cross-links and as a result, on heating, the collagen releases, mainly, denatured alpha-chains into solution (5). Once the pentosidine cross-links of the mature animal have formed in the collagen, the main process of denaturation has to be thermal hydrolysis of peptide bonds resulting in protein fragments of various molecular weights i.e. polydisperse protein fragments. With the "acid process", the collagen denaturation is limited to the thermal hydrolysis of peptide bonds with a small amount of alpha-chain material from acid soluble collagen in evidence (6). Nutritionally, gelatin is not a complete protein food because the essential amino acid tryptophan is missing and methionine is only present at a low level. Type A gelatin (dry and ash free) contains 18.5 % nitrogen, but due to the loss of amide groups, Type B gelatin contains only about 18 % nitrogen (7). Gelatin is abnormally stable and a special catalyst has to be used to obtain the correct Kjeldahl nitrogen content. The amino acid analysis of gelatin (8) is variable, particularly for the minor constituents, depending on raw material and process used, but proximate values by weight are: glycine 21 %, proline 12 %, hydroxyproline 12 %, glutamic acid 10 %, alanine 9 %, arginine 8%, aspartic acid 6 %, lysine 4 %, serine 4 %, leucine 3 %, valine 2 %, phenylalanine 2 %, threonine 2 %, isoleucine 1 %,hydroxylysine 1 %, methionine and histidine <1% with tyrosine < 0.5 %. It should be remembered that the peptide bond has considerable aromatic character, hence gelatin shows an absorption maximum at ca. 230 nm. Collagen is resistant to most proteases and requires special collagenases for its enzymic hydrolysis. Gelatin, however, is susceptible to most proteases, but they do not break gelatin down into peptides containing much less than 20 amino acids. The cross-linking of gelatin with aldehydes is being used to extend the uses of gelatin. In particular, treatment of gelatin films with glutaraldehyde is receiving considerable study in order to improve their thermal resistance, decrease their solubility in water as well as to improve their mechanical properties. In Japan and Brazil the cross-linking of gelatin using the enzyme trans-glutaminase and its use in joining gelatin to other proteins, is approved for food use. An occasional phenomenon is the loss of gelatin solubility after storage in a new kitchen cupboard where the residual formaldehyde vapour from the adhesives used, causes cross-linking of the gelatin. This reaction has been used to make gelatin adhesives water-resistant. Furthermore, the "smokes" used in food preservation are rich in aldehydes and thus can have unwanted reactions with gelatin. ===GELATIN MANUFACTURE=== There are a large number of unit processes used in the manufacture of gelatin and the raw materials from which it is derived are demineralised bone (called ossein), pigskin, cow hide, fish skin and in China, donkey hide is also used quite extensively. In theory there is no reason for excluding any collagen source from the manufacture of gelatin, but the ones above are the currently commercially available raw materials. Interestingly, in countries where pork is sold with its skin intact, there is no pigskin available for gelatin manufacture. There are basically two processes by which collagen is processed to gelatin: The acid process (studied in detail by Reich (9)) is mainly used with pigskin and fish skin and sometimes bone raw materials. It is basically one in which the collagen is acidified to about pH 4 and then heated stepwise from 50°C to boiling to denature and solubilize the collagen. Thereafter the denatured collagen or gelatin solution has to be defatted, filtered to high clarity, concentrated by vacuum evaporation or membrane ultra-filtration treatment, to a reasonably high concentration for gelation and then drying by passing dry air over the gel. The final process is one of grinding and blending to customer requirements and packaging. The resulting gelatin has an isoionic point of 7 to 9 based on the severity and duration of the acid processing of the collagen which causes limited hydrolysis of the asparagine and glutamine amino acid side chains. The alkali process (studied in detail by Cole and Roberts (10)) is used on bovine hide and collagen sources where the animals are relatively old at slaughter. The process is one in which collagen is submitted to a caustic soda or lengthy liming process prior to extraction. The alkali hydrolyses the asparagine and glutamine side chains to glutamic and aspartic acid relatively quickly (11), with the result that the gelatin has a traditional isoionic point of 4.8 to 5.2, however, with shortened (7 days or less) alkali treatment, isoionic points as high as 6 are produced. After the alkali processing, the collagen is washed free of alkali and treated with acid to the desired extraction pH (which has a marked effect on the gel strength to viscosity ratio of the final product). The collagen is then denatured and converted to gelatin by heating, as with the acid process. Because of the alkali treatment, it is often necessary to demineralise the gelatin solution to remove excessive amounts of salts using ion-exchange or ultrafiltration. Thereafter the process is the same as for the acid process - vacuum evaporation, filtration, gelation, drying, grinding and blending. Although gelatin is often considered a commodity like sugar, the descriptions of the processes and raw materials above, should indicates that gelatin has the potential for being a variable product and it behoves users to ensure that they are using the best product for each particular application. In the past, little emphasis has been placed on the animal age of the raw material, particularly in the case of gelatins from bovines, however it is now known that this factor plays a significant role in the molecular structure of the derived gelatin. The role of liming in the alkali process used to be considered one of progressive alkali hydrolysis of the collagen, which made it possible to denature the collagen at lower temperatures and thus maximise the yield of top quality gelatin. Recently, however, it has been shown that the role of liming is limited to the hydrolysis of one collagen cross-link which fluoresces at 290/380 nm and that liming has less and less effect on "extractability" as the animal gets older. The result is that alkali treatment times have been greatly reduced. One of the less well recognised effects of alkali treatment is the "opening up" of the hide collagen, as it is termed in leather manufacture, or the destruction of the proteoglycans associated with the collagen fibrils and this probably results in a more pure gelatin via the alkali process as is indicated by electrophoresis of the gelatin proteins (12). At present, enormous developments are being made in the understanding of the structure of collagen and the changes occurring with senescence, and these developments are bound to have an impact on the appreciation of the variables in gelatin, particularly at the molecular level. ===GELATIN SAFETY=== Gelatin is regarded as a food ingredient rather than an additive and it is Generally Regarded as Safe (GRAS). In 1993 the FDA reiterated the GRAS status of gelatin and stated that there was no objection to the use of gelatin from any source and any country provided that the hide from animals showing signs of neurological disease were excluded and also Specified Raw Materials were excluded from the manufacturing process. Although, at the beginning of the Bovine Spongiform Encephalopathy (BSE) scare in Europe the popular media brought suspicion on all products of bovine origin as being possible transmitters of the disease to humans as CJD, this was a thoroughly unscientific assessment of the dangers of spreading infection. It is now recognised that BSE is a neurological and brain problem and not associated with the hide of the animal. It is also recognised that the processes of manufacturing gelatin make it virtually impossible for the survival of a defective prion, if it were present in the first place. Detailed and unbiased information on BSE is available from the Institute of Food Science and Technology Web site. Hence, today, gelatin retains its GRAS status. Furthermore, the Joint Expert Commission on Food Additives (JECFA) placed no limit on the use of gelatin in 1970. Gelatin is an excellent growth medium for most bacteria, hence considerable care needs to be taken, during manufacture, to avoid contamination. This care is evidenced by the use of documented HACCP programs by manufacturers. In the same way to ensure product reproducibility, most companies are implementing ISO 9000 quality management systems. ===GELATIN PROPERTIES AND USES=== ====Solubility in water==== Gelatin is only partially soluble in cold water, however dry gelatin swells or hydrates when stirred into water. Such mixtures should generally not exceed 34 % gelatin. On warming to about 40°C gelatin that has been allowed to hydrate for about 30 minutes melts to give a uniform solution. Alternatively, dry gelatin can be dissolved by stirring into hot water, but stirring must be continued until solution is complete. This method is normally only used for dilute solutions of gelatin. If gelatin solutions are spray dried or drum dried from the sol state, the resulting gelatin is "cold water soluble" and such gelatins gel quickly when stirred into cold water. These gels are generally not clear, so the use of this form of gelatin is limited to milk puddings and other products where solution clarity is not required. The compatibility of gelatin in aqueous solution with polyhydric alcohols like glycerol, propylene glycol, sorbitol etc. is virtually unlimited and they are used to modify the hardness of gelatin films. In products with limited moisture availability, as in confectionery, and where there is another polymer, as in glucose syrup, competing for the available water, then gelatin can be precipitated resulting in loss of gelation and cloudiness. In these cases the gelatin solubility is very dependent on the charge on the protein molecule or the pH of the product. Hence, the further the product pH is from the isoionic pH the better will be the solubility and performance of the gelatin. ====Adhesive properties==== Possibly the oldest use of gelatin was as animal glue. For adhesion to take place a warm gelatin solution must be used and the gelatin must not have gelled before the surfaces to be glued are brought together. An example of this use of gelatin is in pharmaceutical or confectionery tableting and in liquorice all-sorts where it can be used to join the layers. ====Gelling properties==== The most common use of gelatin is for its thermally reversible gelling properties with water, for example, the production of table jellies. Gelatin is also used in aspic to add flavour to meat products while on gelling it also provides a pleasing shiny appearance to the product. In some cases gelling is known as its "water absorbing property": For example, in canned hams, gelatin can be added to the can before cooking. On cooking the exudate from the meat is absorbed by the gelatin and appears as a gel when the can is opened. In confectionery, gelatin is used as the gelling binder in gummy products, wine gums etc. In the manufacture of these products gelatin is combined with sugar and glucose syrups. Incompatibility between gelatin and glucose syrup can occur (13) and is a function of the concentration of glucose polymers containing more than 2 glucose units, contained in the syrup. Competition between gelatin and glucose polymers for water in low water content products can result in, at worst, precipitation of the gelatin and at best a marked loss in gelling properties or hardness of the product. It is also known that different gelatins with similar properties in water, can have very different properties in confectionery formulations. Some raw fruits like pineapple and papaya contain proteolytic enzymes like bromelin which hydrolyse gelatin and destroy its gelling ability. In such cases it is essential that the fruit is cooked to destroy the protease before the fruit is added to gelatin solutions. In general one can say that the lower the mean molecular weight (MW) of a gelatin the lower the gel strength and viscosity of its solution, however it has been shown that the collagen alpha-chain (MW 100 kD and gel strength = 364 g Bloom) is the main contributor of gel strength (14) and that higher molecular weight components (beta-chain with MW 200 kD, gama-chain with MW 300 kD and "microgel" with MW > 300 kD) make a relatively low contribution to gel strength but a high contribution to viscosity. ====Foaming properties==== Gelatin is a very efficient foam stabiliser and this property is exploited in the manufacture of marshmallows. Different gelatins have different foam stabilising properties and gelatin for this use needs to be carefully selected. However, the foaming properties can be standardised by the use of sodium lauryl sulphate (15), if this is permitted by local food additive regulations. In marshmallows the gelatin's film forming properties are also used to stabilise the foam on cooling, and because the product is normally not acidified, it has to have a much lower moisture content (>85 % solids) than gummy products (76 % solids) to avoid mould growth in storage. ====Protective Colloid/Crystal habit modifying properties==== If a gelled jelly is frozen, the product will suffer from syneresis and on thawing the clear jelly will disintegrate with much exuded water. However, if water containing 0.5 % gelatin is frozen, the water will freeze as millions of small discrete crystals, instead of forming a single solid block of ice. This effect is most desirable in "ice lollies" and is also used in ice cream manufacture to obtain a smooth product with small ice crystals and also to ensure that any lactose precipitates as fine crystals avoiding the development of graininess with time. ====Film Forming properties==== Gelatin's film forming properties are used in the manufacture of both hard and soft (pharmaceutical) capsules. Gelatin films shrink with great force on drying, hence such uses usually involve the addition of polyhydric alcohols to modify the adhesion and flexibility of the dry film. Also, for film forming, a gelatin with a high viscosity is preferred to one with a low viscosity, hence for hard capsules and in photography, ossein gelatin is preferred and commands a premium price. ====Emulsifying properties==== The amphoteric character as well as hydrophobic areas on the peptide chain gives gelatin limited emulsifying and emulsion stabilising properties used in the manufacture of toffees and water in oil emulsions like low fat margarine. ====Stability==== Dry gelatin has an almost infinite shelf life as long as the moisture content is such as to ensure that the product is stored below the glass transition temperature. The stability of gelatin in solution depends on temperature and pH. Generally, to minimise loss of gel strength and viscosity with time, the pH of the solution should be in the range 5 to 7 and the temperature should be kept as low as possible, consistent with the avoidance of gelation and the suitability of the solution viscosity to the particular application. Often the cause of degradation or hydrolysis of gelatin in solution is microbial proliferation, so gelatin solutions should not be stored for longer than is absolutely necessary, and after addition of the acid to confectionery formulations, the solution should be used and cooled/gelled with minimal delays. ====Microencapsulation - Mixed film forming properties==== Besides being precipitated by polymers competing for water, gelatin is amphoteric, i.e. it has both positive and negative charges on the molecule (and no net charge at the isoionic point). Hence, at a pH where the basic side chains do not carry a charge, acid groups for example from gum arabic can react with the basic groups of gelatin to form an insoluble gelatin-arabate complex which can be precipitated around emulsified oil droplets, forming micro-ecapsulated oil. The microcapsules are hardened with formaldehyde or glutaraldehyde before harvesting and drying. In this application the pI of the gelatin is critical. This process has been used in the food industry for encapsulating flavours. ====Milk - Food stabilising properties==== Gelatin is used as a stabilizer particularly in yoghurt, where the addition of 0.3 - 0.5 % acts to prevent syneresis thus allowing the production of stirred and fruit containing products. In this instance the gelatin reacts with the casein in the milk to reduce its tendency to separate water from the curd. Gelatin can also be used in cheese manufacture to improve yield and in the stabilisation of thickened cream. ====Fruit Juice Clarifying properties==== In "fining" applications, gelatin reacts with polyphenols (tannins) and proteins in fruit juices forming a precipitate which settles leaving a supernatant which is stable to further cloud formation with storage time. In wine, usage levels are about 1 to 3 g/hL and excess usage, which would lead to protein instability, needs to be avoided. Traditionally, low Bloom strength gelatins are used but it has been shown that high Bloom strengths are equally effective (16). However, from the practical point of view, the use of low Bloom Strength gelatin is cheaper and makes it easier to mix the gelatin into the bulk of the cold juice before gelation can occur. In this regard, it has become common practice to treat cold grapes, during the initial crushing process, with gelatin that has been hydrolysed to the extent that it can no longer gel. ====Texturising properties==== Gelatin is used in dried soups to provide the appropriate mouth feel (viscosity) to the final product. ====Nutritional properties==== As stated earlier, gelatin is not a complete protein source because it is deficient in tryptophan and low in methionine content, however the digestibility is excellent and it is often used in feeding invalids and the high level of lysine (4 %) is noteworthy. More controversially, studies have shown that the consumption of 7 to 10 g/day can significantly improve nail growth rate and strength (17) and it also promotes hair growth (18). Gelatin has also been shown to benefit arthritis sufferers in a large proportion of cases (19). ====Corrosive properties==== Although 304 stainless steel (s/s) can be used with milk, gelatin attacks 304 s/s and tubing can be perforated after a few months of continuous usage. With gelatin, it is essential to use 316 s/s and if heat exchanger plates are involved, the use of 316 s/s with the minimum specified molybdenum content of only 2 % can be unacceptable. ====Fish skin gelatin==== Fish skin gelatin is available commercially and can be produced for kosher use provided that the appropriate conditions are met (such as the use of fish having scales). Fish gelatin with normal gel strength has a normal hydroxyproline content (21) and is made from fish from warmer waters and not necessarily from fresh water, although this is normally the case. Fish gelatin with low or no gel strength (20), has a low hydroxyproline content (7) and is produced from cold water species which are sourced typically from the sea. The low gel-strength gelatin has been used to emulsify vitamin A before spray drying to give another type of microencapsulated product using gelatin. ===GELATIN TESTING METHODS=== The best published sources of gelatin testing methods are British Standard 757 of 1975 (22) or Standard Methods for sampling and testing gelatin, published by the GMIA (23) or the Pharmacopoeias. Many of the methods used in laboratories need to be modified to suit the peculiarities of gelatin. ====Identification==== Gelatin gives the normal positive trichloroacetic acid, biuret, ninhydrin tests for protein. The precipitate with 5 % tannic acid is a particularly sensitive test for very dilute solutions of gelatin. In addition the thermally reversible gelation of a 6 % solution in water between 10 and 60°C is unique for this protein. ====Gel Strength==== The most important attribute of gelatin is its gel strength and when determined by the standard method (22), is called the Bloom Strength. This is the force in grams required to press a 12.5 mm diameter plunger 4 mm into 112 g of a standard 62/3% w/v gelatin gel at 10°C. Several penetrometer type instruments have been adapted to determine Bloom Strength. A frequent question is how to substitute gelatin of one Bloom Strength for a gelatin of another. As a guide one can say: C x B½ = k (24) or C1(B1)½÷(B2)½ = C2 Where C = concentration, B = Bloom strength and k = constant, however, there are other considerations besides gel strength which can invalidate such a substitution calculation. For example, in a gummy formulation, the texture using 250 Bloom gelatin is far shorter than when 180 Bloom gelatin is used. ====Viscosity==== From the point of view of functionality, the solution viscosity of gelatin is probably the second most important parameter. The standard method calls for the viscosity of a 62/3 % solution at 60°C. Low viscosity (and a high gel strength) is required for poured confectionery, and high viscosity for film forming applications. In viscosity calculations, usually C logV = k but the model is not as good as is the mathematical model for Bloom calculations. ====Colour and Clarity==== Solution colour and turbidity or clarity are attributes which may or may not be important depending on the application. Poor clarity markedly affects the ability to measure colour (25) and at this stage there are no internationally accepted methods for determining these attributes, however, if clarity is good, then gelatin colour obeys Beer's Law. ====pH==== Solution pH (1%) is usually about pH 5 but can vary considerably. At this pH the viscosity of Type B gelatin is minimal and the gel strength is maximal, hence from the manufacturers point of view it is advantageous to manufacture gelatin at this pH. However, due to the strong buffering capacity of gelatin this pH may not be the most advantageous for the customer. ====Moisture==== The moisture content of gelatin may be as high as 16 %, however, more normally it is about 10 % to 13 % because at 13.0 % moisture content the glass transition temperature (26) of gelatin is about 64°C which allows particle size reduction to be a simple operation. In addition, at 13 % moisture content and 25°C gelatin is close to equilibrium with ambient air moisture contents of ca. 46 % RH. At 6 % to 8 % moisture content gelatin is very hygroscopic and it becomes difficult to determine the physical attributes with accuracy. Due to the variable granule size of gelatin, the rate of moisture loss at 105°C can be variable. Hence it is normal to add water to the gelatin powder before placing the sample in the drying oven. This means that the gelatin melts and water is lost from a uniform thin film of protein. It should be noted that metal dishes have to be used because, on drying, the film of gelatin shrinks and breaks containers of glass or ceramic. Finally, the drying of gelatin to very low moisture contents results in cross-linking and loss of solubility. It is thus difficult to distinguish between free and bound water in gelatin. ====Ash==== The gelatin ash content is determined by pyrolysis at 550°C. Usually ash contents up to 2.5 % can be accepted in food applications. However the nature of the ash can be important. For example, 2 % CaSO4 in gelatin can have excellent clarity in spite of the solubility product of the ash being exceeded (due to the crystal-habit modifying effect of gelatin), however on dilution of the gelatin in a confectionery formulation, the ash can precipitate. Furthermore, ammonia is often used as a pH modifier in gelatin preparation and salts like NH4Cl are not determinable by pyrolysis. ====Sulphur dioxide content==== Sulphur dioxide is used as a biocide and bleach in gelatin manufacture. The nationally permitted level of residual SO2 in gelatin is variable and the methods for its determination can give a great variation in results. It is known that gelatin promotes oscillating redox reactions (28,29) and the control of this contaminant is not easy. Hydrogen peroxide is often used to control the SO2 content of gelatin and sometimes the permitted level of this contaminant is also specified. It is interesting to note that both H2O2 and SO2 can be shown to coexist in gelatin. ====Heavy Metal content==== Once again the determination of heavy metals in gelatin can be a problem because of the difficulty of completely degrading gelatin and also because the main component of the ash in gelatin can be of low solubility, like calcium sulphate, hence with a variable ability to absorb traces of heavy metals. It must be recommended that internal standards be used wherever possible. ====Isoionic point==== The isoionic point of gelatin (27) is best determined by passing a 1 % solution of the gelatin at 40°C through a mixed bed column of ionexchange resin (Rohm & Haas MB3) at a flow rate of not more than 10 bed volumes per hour and measuring the pH of the eluate. It should be noted that on cooling, isoionic gelatin has poor clarity and the conductivity should be between 1 and 5 s/cm for Type B gelatin. ====Microbiological properties==== Gelatin is an excellent nutrient for most bacteria, hence the manufacturing processes have to carefully avoid contamination. Most countries have microbiological specifications for gelatin, but generally they are not very onerous. Total mesophyllic plate counts of 1000 are generally accepted with various countries limiting the presence of Coliforms, E. Coli, Salmonella, Clostridial spores, Staphylococci, and sometimes even Pseudomonades. ===BIBLIOGRAPHY=== ====General References==== A.J. Bailey and N.D. Light. Connective tissue in meat and meat products. Elsivier Applied Science. London and New York. (1989). M. Glicksman. Gum Technology in the Food Industry. Academic Press New York and London. (1969). G. Stainsby. Recent Advances in Gelatin and Glue Research. Pergamon Press, London New York, Paris, Los Angeles. (1958). A. Veis. The Macromolecular Chemistry of Gelatin. Academic Press - New York and London. (1964). A.G. Ward and A Courts. The Science and Technology of Gelatin. Academic Press. London . New York . San Francisco. (1977). ====Citations==== 1. A.J. Bailey and R.G. Paul. Journal of the Society of Leather Technologists and Chemists. 82(3), 104-110. (1998). 2. M. Glicksman. Gum Technology in the Food Industry. Academic Press New York and London. pp. 359-397. (1969). 3. A.J. Baily and N.D. Light. Genes, Biosynthesis and Degradation of Collagen in Connective tissue in meat and meat products. Elsevier Applied Science. London and New York. (1989). 4. D.J. Prockop. Matrix Biol. 16(9), 519-528. (1998). 5. C.G.B. Cole and J.J. Roberts. Proceedings of the International Union of Leather Technologists and Chemists Societies Congress. London. 57-64. (1997) 6. C.G.B. Cole and J.J. Roberts. Journal of the Society of Leather Technologists and Chemists. 80, 136-141. (1996). 7. J.E. Eastoe and A.A. Leach. A survey of recent work on the amino acid composition of vertebrate collagen and gelatin in Recent Advances in Gelatin and Glue Research. Ed. G. Stainsby. Pergamon Press, London . New York . Paris . Los Angeles. 1958. 8. P.V. Stevens. Food Australia. 44(7), 320-324. (1992) 9. G. Reich, S. Walther, F. Stather. Deutsche Lederinstitut, Frieberg/SA. 18, 15-23. (1962). 10. C.G.B. Cole. The Occurrence of Dark Coloured Gelatin. in Occurrence, Measurement and Origins of Gelatine Colour as Determined by Fluorescence and Electrophoresis. 19-155. Thesis. University of Pretoria. Pretoria. 0002. South Africa. 11. A. Veis. The Macromolecular Chemistry of Gelatin. Academic Press - New York and London. 196. 1964. 12. C.G.B. Cole and J.J. Roberts. Journal of the Society of Leather Technologists and Chemists. 80, 136-141. (1996). 13. W.M. Marrs. Gelatin/carbohydrate interactions and their effect on the structure and texture of confectionery gels in Progress in Food science and Nutrition 6, 259-268. Ed. G.O. Phillips, P.A. Williams, D.J. Wedlok. Pergamon Press. Oxford . New York . Toronto . Sydney . Paris . Frankfurt. 1982. 14. E. Heidemann, B. Peng, H.G. Neiss, and R. Moldehn. Proceedings of the 5th IAG Conference: Photographic Gelatin. Ed. H. Ammann-Brass and J. Pouradier. International Arbeitsgem. Photogelatine, Fribourg, Switzerland. 15. Federal Register. May 15, 1964. p. 6383. 16. W. Bestbier. Wynboer. 621, 6-62. (1983). 17. M. Schwimmer and M.G. Mulinos. Antibiotic Medicine and Clinical Therapy. IV(7), 403-407. (1957). 18. United States Patent 4,749,684. (Jun.7, 1988). B. Silvestrini ( to Bruno Silvestrini). 19. M. Adam. Therapiewoche 38, 2456-2461. (1991). 20. A.G. Ward. Conversion of collagen to gelatin, and chemical composition in Recent Advances in Gelatin and Glue Research. Ed. G. Stainsby. Pergamon Press, London . New York . Paris . Los Angeles. 1958. 21. European Patent 0 436 266 A1. (Published 10.07.91). S. Grossman. (to Bar Ilan University 22. Methods for sampling and testing gelatine. BS 757 : 1975. Gr8. British Standards Institution. 2 Park St. London W1A 2BS 23. Gelatin Manufacturers of America, Inc. Standard Methods for Sampling and Testing of Gelatin. GMIA, Inc., New York, 1986. 24. A. Veis. The Macromolecular Chemistry of Gelatin. Academic Press - New York and London. 392-396. 1964. 25. C.G.B. Cole and J.J. Roberts. "Gelatine Colour Measurement". Meat Science. 45(1), 23-31. (1997) 26. M.H. McCormick-Goodhart. Research Techniques in Photographic Conservation. Proceedings of the Copenhagen Conference. 65-70. (May 1995). 27. A. Veis. The Macromolecular Chemistry of Gelatin. Academic Press - New York and London. 107-113. 1964. 28. C.R. Chinake and R.H. Simoyi. S.Afr.J.Chem., 48, 1-7. (1995). 29. Z. Melichova, A. Olexova and L. Treindel. Chemical Abstracts. Number 123:267635. Z. Phys. Chem. (Munich). 191(2), 259-64. (1995). 251c1fa0adb5569e49c8f02f70be756389cba40d 0 283 413 2006-04-30T17:52:13Z Colin Kaminski 0 Isoionic point wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Impressionism''' - art movement in which painters broke away from the techniques of continuous brushstrokes and clearly expressed detail. They were largely concerned with the effects of light and color. *'''Infectious development''' - development action which occurs in processing "lith" materials. The oxidation of hydroquinone produces new and highly active reducing agents, semiquinones, in the presence of a low quantity of sodium sulfite. This results in a very high contrast image. *'''Intensification''' - chemical method of increasing the density of the photographic image. It is only suitable for treating negative materials and works better on negatives that have been underdeveloped rather than underexposed. *'''Intermittency effect''' - states that, a number of short, separate exposures will not produce the same photographic result when combined as a single exposure of equivalent total duration. *'''Intersection of thirds''' - compositional technique whereby the image area is divided horizontally and vertically into equal thirds by means of four imaginary lines. The main subject is considered strongly placed it it is positioned at the intersection of any two of these lines. *'''Inverse square law''' - states that, when the light source is a point, illumination on a surface is inversely proportional to the square of the distance of the light source. *'''Iodine''' - chemical used in reducers and bleachers. *'''Isoionic Point''' - The pH where the concentration of the dipolar ion is at a maximum *'''Ivorytype''' - obsolete printing process designed to give the impression of a painting on ivory. A hand colored print was impregnated with wax and squeegeed face down on hot glass. The paper base was then back by ivory tinted paper. ce411fc9568baa73f7175267ab508af4b5962e52 6 149 569 149 2006-05-01T01:24:42Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 234 315 2006-05-01T02:22:21Z Colin Kaminski 0 wikitext text/x-wiki Files either cut by being abrasive or by being sharp. Abrasive files work like sand paper. Diamond is the most common abrasive file. (Another realated tool is the [[Rasp]]. Cutting files come in different shapes: *Mill *Round *Half-Round *Machinists' Flat *Three-Square *Square *Flat *Taper *Knife *Warding And in different tooth patterns (Listed from Coarse to Fine): *Coarse double-cut *Coarse *Bastard double-cut *Bastard *Smooth *Dead Smooth *Fine Files can be sharpend a few times by being placed in an acid bath. If you use lots of files it is worth the cost if you only need to replace a couple of files each year don't bother sharpening. After the teeth are cut on a file the file is hardned. This makes them easy to break. That can be used to yor advantage if you need to shorten a file. After shortening, grind the end making sure not to heat the file. (Use a bucket of water to cool the file after every few seconds of grinding. Choose course files for softer materials and for leaving rougher surfaces with quicker stock removal. Choose finer files for harder materials and finer finishes with slower stock removal. f6cb1350e1d5f3adda571a68477f5b5fe3e46240 6 91 821 91 2006-05-01T14:15:08Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 93 825 93 2006-05-01T14:15:52Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 473 1096 2006-05-01T14:18:59Z Colin Kaminski 0 wikitext text/x-wiki '''Rasps''' [[Image:RaspTeeth.jpg]] A rasp looks like a file but instead of having long teeth the theeth are brought to points. The come in a varity of shapes and tooth patterns. For the smoothest finish use rasps that have been cut by hand to a random tooth pattern. They come in a varity of shapes and teeth patterns. A inexpensive general porpous rasp is called a 4 in 1 rasp and has four tooth patterns on one rasp. '''Rifflers''' [[Image:Riffler.jpg]] Rifflers are related to rasps however a riffler has the cutting surface bent to lift the handle out of the work area. Rifflers are used for cutting shallow depressions. Rasps and rifflers should only be used on soft materials like wood, soapstone etc. Metal will dull them quickly. They can be sharpened many times in an acid bath. 043599f63d77bbb44c8a9b73a7685a07c558faf6 6 19 923 19 2006-05-03T03:32:39Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 20 925 20 2006-05-03T03:33:17Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 18 911 18 2006-05-03T03:33:53Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 405 961 2006-05-03T04:34:02Z Colin Kaminski 0 /* Sharpening Knives */ wikitext text/x-wiki A knife is a broad word encompassing a large number of tools. The cheapest knife to buy and maintain is an x-acto knife. [[Image:XactoNo1.jpg]] The no. 1 knife handle with the no. 11 blade is the most common knife we associate with X-Acto but they make a broad product line for model makers. The blades are stainless and never get as sharp as a steel blade. [[Image:XactoX2000.jpg]] A more comfortable handle is the X-2000. X-Acto knife blades are cheap enough that sharpening is not required. The blades are simply replaced. [[Image:ViolinMakersKnives.jpg]] A better knife is a violin makers knife. You can sharpen the blade and trim back the handle for a lifetime. They are available in German steel and Japanese Steel. The German steel is more durable (chips less easily). The Japanese steel gets sharper and stays sharp longer but chips quite easily. ===Sharpening Knives=== Sharpening knives is a task of patience. You must completely sharpen one face to completion before moving on to a finer grit. You may stop at anytime the knife is sharp but what is described below will make a knife sharp enough to shave. [[Image:KniveAngles.jpg]] The angle you sharpen at is chosen based on what the knife will be used for. Use a blunt angle for rough work and a durable blade and use a sharp angle for delicate work. [[Image:KnifeSharpening.jpg]] *Rough out both sides in a single plane with a course stone. *Polish the faces with a fine stone. *Hone the knife on a leather strop with red compound (rouge). *Hone the knife on a 2nd leather strop with white compound. [[Image:KnifeSharpeningStages.jpg]] Tips: *Do not switch to fine grit until all chips have been removed. *Be careful to not round the edge. You need one plane from the shank of the knife to the edge. *Sharpen both sides evenly. Safety Tips: *Do not pull a knife towards your body or fingers. [[Image:KnifeSharpeningTips.jpg]] ===Links=== [[http://www.frets.com/FRETSPages/Luthier/Technique/ToolUse/KnifeTechnique/knifetech01.html Master Luthier Frank Ford on Knives.]] eb1ce34b412a47edb5796a31f60ae8807c389e3b 0 246 339 2006-05-03T11:59:00Z John Pecora 0 wikitext text/x-wiki [[Image:GlassCutter.jpg]] Glass cutters work by damaging the glass along a specific line. For a straight cut place a straight edge along the work and score the glass with the wheel. After scoring, the glass is placed with one end of the underside of the score (score still on top) on top of and centered over the ball. Then an even pressure is applied to both sides of the glass. If the glass is large (a long score), a second ball should be used, one under each underside of both scored ends or a straight edge place at the underside just at the score. Since glass will tend to break where it has been damaged it will break along the line. Tips *Using a steel or aluminum square for cutting glass Holo-Plates insures the glass is square. *Make sure the glass cutter is sharp (not worn out). *Make sure the cutter wheel spins freely. *Don't use excessive pressure. *For straight lines use a steel rule or similar. *Make sure to start at the edge of the glass. *Keep even pressure along the entire score. *Keep a smooth continuous motion until done, do not stop and restart. *Only make one score - If the cutter skips only go over the unscored part but try to avoid this. *Pay special attention to the end of the cut. *Some people find the ball at the handle end useful to tap the score line for thick glass. *Keep the score on top and break the glass down. *After the break, the noches on the cutter can be used to break off parts that did not break at the score but they will alway be rough and sharp. Safety: *Wear eye protection. *Handle large sheets with your finger tips and never your palms. a79d5bac40f8cd11af74185077ecb592d3ea1b7b 0 254 355 2006-05-03T13:04:25Z John Pecora 0 wikitext text/x-wiki A hand tap is used to make threads in a drilled hole, usually but not exclusively in metal. The tap looks like a bolt as it has threads but the thread are tapered from narrow at the point to the standard bolt thread size as you go up and the tap is usually made from a very hardened steel. Which means they are very hard but can snap or break easily. So do not use excessive force. It is better to take smaller cutting turns then described below then to force and break the tap off in the hole. As the tap is hardened it is almost impossible to drill out or remove one is has been forced and broken off in a hole. The tap usually has a cross bar at the top to allow ease of turning the tap. There are tap charts to look up the drill bit size to use for drilling the hole for final tap size. There are many size taps depending on bolt size. There is also a regular through tap and a bottom tap. When using a bottom tap is it recommended to use a through tap first to get the threads started, then use the bottom tap to finish the job. A bottom tap is used to tap a hole that does not go all the way through the material (thus past the taper on a through tap) but the threads should reach as close to the bottom of the hole as possible. For steel the most important thing is to keep the tap and hole well lubricated with oil. More and often is better then not enough. A good cutting oil is recommended. Once the hole is drilled insert the tap into the hole and rotate it clockwise (for standard bolts) gently until you feel it bite trying to keep it as perpendicular to the work as possible. Then rotate it clockwise another 1/4 turn. Turn it counterclockwise 1/4 turn. This breaks away the cut metal from the cutting threads. Again rotate it clockwise for 1/2 a turn and then counterclockwise 1/4 turn. Repeat the 1/2 turn clockwise and 1/4 turn counterclockwise until the depth desired is reached or the entire hole has been taped which is easy to tell as there will be no more pressure resistance on the 1/2 turn clockwise cutting motion. The tape can then be backed out. Some soft materials like aluminum that are thin do not need the counterclockwise backout cuts an can be tapped simply by continuing to turn clockwise. But as thickness and hardness of the material increases this step will be needed. A final note is that if you try to tap without the counterclockwise backup cut for quite a few turns and then find you need to use it as the cutting it getting very hard, it may be impossible to do the backout cut. So it is better to use the backout cut if unsure. 5d3e1a493021cf3d3ce5e42f436347c327b53e36 0 253 353 2006-05-04T11:03:05Z John Pecora 0 wikitext text/x-wiki A hand die is used to put bold thread on a piece of rod stock. A hand die looks like a hexigontal disk with a center hole shaped like a four leaf cloverthat has threads on it. The outside hexigontal fits into a handle to ease the turning of the die when cutting the thread on a rod stock. The threads are tapered thus a smaller diameter on one end and a larger diameter on the other end. There are diffferent die sizes for different stock rod sizes. If the rod is soft material the counterclockwise cut off steps, as described below, may be elliminated. First oil both the die and the rod stock and keep it well lubricated. More and often is better then not enough. Then find the larger diameter threaded side of the die. This will be marked on some dies. This larger diamter is the side the fits over the rod stock first. Start to turn the die clockwise (for standard bolt threads) until it starts to bite into the rod stock while keeping the die perpendicular to the rod stock. Once the die has started to bite into the rod stock, turn the die another 1/4 turn clockwise. Then turn the die 1/4 turn counterclockwise. This cuts away the material from the die and you can feel pressure give to ease of turning. Continue to turn the die 1/2 turn clockwise then 1/4 turn counter clockwise until the length of threading needed is complete. Once complete, unthread the die (counterclockwise) off the threaded rod stock. eb5850c671df1db90d3745b8d5c81bf70d8c2378 0 252 351 2006-05-04T11:22:03Z John Pecora 0 wikitext text/x-wiki Hack saws are hand saws that are used to cut metal. First, as with any material removal in metal, keep the blade and material well lubricated with cutting oil. This can be elliminated and is not as important with soft metals but is needed and will save your hacksaw blade with harder materials. They usually have finer teeth then wood hand saws and the blade should be put in such that the teeth point toward the user handle, not away from the user handle as in a wood saw. As the teeth are pointing toward the user, the cut into the metal is done on the pull stroke and not the push stroke. This allows a finer and more straight cut as the blade pressure during the cutting stroke is from the solid handle and not the tensioned far end. Finer teeth are used for harder metals and courser teeth used for softer metals like aluminum but both should still be metal cutting blades. Fine teeth can be used for hard and soft metals but course teeth should only be used for soft metals. Only apply slight pressure on the pull (cutting) stroke and no perssure at all on the push stroke. Do not force or excesssively bear down on the saw. Most of the time after the piece is cut there will be a burr on the end of the material. This can be filed or sanded away. 1ab56d044f06d5387e253916de943057fe64cce9 0 431 1012 2006-05-07T16:04:35Z Colin Kaminski 0 /* Chapter 2 */ wikitext text/x-wiki This is a work in progress. Check back in a few months. ===Manual of Interfermetric Photography=== by A. Berthier, 1895 *Translated by Colin Kaminski. *Note: Colin doesn't speak French so this translation is aproximate. Please see the french version on this site for the original text. ===Introduction=== HANDBOOK OF PHOTOCHROMY INTERF ÉRENTIELLE. Since the publication of the remarkable experiments of Mr. Lippmann, physicists have sought to reproduce them. Some succeeded, others were less happy and obtained only not very encouraging results. The study of successes as well as that of the vexations is extremely instructive, because it makes it possible to determine rather exactly the conditions of the experiment and, by the fact, the procedure to employ to achieve the desired goal. There does not exist, until now, of the scientific raity explaining in detail the method to follow in the by interferential reproduction of the colors; the majority of the experimenters who took the route opened by Mr. Lippmann are of a too tested discretion, with regard to the practical details of the process they are useful. In fact, obtaining perfect tests being still at the present time surrounded with difficulties, each one was ingénié in Jes to better overcome of sound, and such artifice which makes an admirable success with one, gives between the hands of another only a poor result. One would not thus know, for the moment, to give a method absolute and final; it is to better show details the various processes employed by the most skilful researchers, to allow each one to make a suitable selection. One could better start only by quoting the creator himself of the interferential method, Mr. Gabriel Lippmann. ===Chapter 1=== the REPAIR OF the LAYER SENSIBJ, E. 1. - LlppmanlL process Spectrum photographs. - In the month of 1' 1:vrier 1891, Mr.. Lippmann, professor de good Physique it it SOl', announced with the Academy of Science that I! to photographi.er the solar spectrum had arrived. Reports of the Academy of Science (T exile, p. ' l74 and suiv.) contain this important communication completely. Here is the talk: "I proposed, said \ Mr. Lippmann, to obtain on a photographic plate the image of the spectrum with!les colors, in such way that this image deIneurât from now on fixed and p11t to remain indefinitely exposed at the great san day!! to deteriorate. "I could solve this problem while operating with the significant substances, los developers and fixed them current hairs Photographs some, and by modifying sim 1"the ARTIE. - OPERATIONAL PROCESSES. plement physical conditions of the experiment. The essential conditions to obtain the colors Photographs sout two of it: ID continuity of the sensitive layer; 2d presence of a reflective surface leaned with this layer. "I understand by continuity the absence of, grains: it is necessary that the iodide, the silver bromide, etc, are disseminated inside a blade of albumin, gelatine or another transparent or inert mâtière, a uniform way and without forming grains which are visible even with the microscope; if there are grains, it is necessary that they are of negligible size compared to ID. luminous wavelength. "the use of the coarse used emulsions ' today is by there excluded, a continuous layer is transparent except usually a light blue opalescence. I employed like support the albu. mine, collodion and the gelatine, like matters "sensitive ioùure and the silver bromide; all these combinations give good results. "the plate, dries, is carried by a hollow frame where mercury is poured; this, mercury forms "reflective surface in contact with sible layer SEN. The exposure, the development, the fixation, ', make as if one wanted to obtain a negative black of the spectrum; but the result is different: when the stereotype is finished and dried, the colors appear. "the stereotype obtained is negative by transparency, it be-with-ùire each color is represented by its complementary. By reflexion, it is positive, and one sees the color itself, which can be obtained very brilliant. To obtain positive thus, rél' is needed 3rd. 1st or sometimes to reinforce the image so that the die. could photographic has a clear color, which is obtained, as one knows, by the use of liquors acidùs.. " One fixes at the soda hyposulphite followed neat C Inva' ges: I have vérifl, 6 that then the colors resisted the light électrique.la plus inlens ". " The theory of the experiment is very simple. Read. incidental mière, who forms the image daus the darkroom, interferes with the light rétléchie by mercury. It is formed, consequently, in the interior of the sensitive layer a system of fringes, i.e. the maximum luminous one and obscure minima. Be maximum only impress the plate; following the photographic operations, these maximum remains marked by more or less reflective money deposits which occupy their grip. The sensitive layers so find divided! by these deposits in a series of blades minees which have for épaisscur J' interval which separated two maximum, it ost-with-statement a domi-Ionguor of wave of the incidental light. These!times minees has thus precisely I thickness necessary for repl' to oduir J) Los visible colors on the stereotype are thus of comparable nature that those of soap bubbles. They are only more pure and brilliant plu!l, at least, when the photographic operations gave a quite reflective deposit. That is due with what it is formed dans the thickness of the sensible layer a very great number of superimposed thin blades: approximately 200, if the layer has, for example,tu miIlimèt~e. For the same reasons, ]a considered color is of as much pltJs pure that the number of the reflective layers increases. These layers form, indeed, an in-depth form of network, and for the same reason as dnns the network analysis by reflexion, the purity of the colors is growing with the number of the elementary mirrors, U In his first experiments, Mr. Lippmann was useful himself of the process to the collodion and the albumin of Taupenot. This process presents the avantages' those at collodion and albumin, in the sense that it perm6& of conser\' gold los ices after their preparation. An inherent defect with the process on albumin lies in the difficulty in obtaining homogeneous layers (exemptesde bubbles, etc). Mr. Taupenot, by extending albumin on a porous surface of collodion, faH to act porous fibres of this layer on the microscopic bubbles, so as to do them disparaitl:e; One can be useful oneself of sensitized and washed collodion, or collodion mêmo not iodized (Gaumé). The ice, cleaned well, is covered with ordinary collodion, which one sensitizes and which one washes as for the process,au ()ollodion. L~glace being drained, after the dèrnièr washing; 011' iarècouvrè('. from albumin, exactemeut as one extends collodion, I and one lets run out excess in a special bottle. 011 employs, for this preliminary albumenizing, least possible of albumin, which is only used to drive out water and which one throws then. When the ice is well drained, one covers it with new albumin. The ices are dried like the ices with tannin. They are preserved inrléfinirrient. One sensitizes them a few days before making use of it I they conser\' ent this sensitivity during one year. One operates this sensitizing while plunging them san, S downtime in a bath C *Eau 100" *Nitrate d'argent. . '. .. ... ... .. . . ::. 10" *Nitrate de soude 10 *Acide acétique cristaIUsable . ... , 10 The time of immersion should not exceed twenty seconds. The ice, withdrawn of this bath, is plunged in the distilled water contained in a wood tank, where it remains ten garlic minutes less, then in a tank filled with ordinary water. Withdrawn, it is abandoned Li the desiccation, supported against the wall, and dans the most complete darkness. The exposure to the light is a little shorter than with ordinary albumin (1). The plates obtained thus are extremely transparent: their grain is very fine, but their SENsibility is relatively low, If one substitutes the bromide ù. ' the money iodide, one makes a success of it slightly exalter this sensitivity. The plates are then prepared in the manner sui praises: 011 begins raI' to cover the ' ice with collodion which one sensitizes in a nitrate bath, then, after lavn:ge, one covers it, collodion of a layer a]bumineuseformée by an albumin solution containing} ù. ~ for 100 of potassium bromide. The plates "once dry, are subjected during two minutes it a bath of *Water. 100 parts. *Acetic silver nitrate 10 *Acid 10 Like all the preparations with silver bromide, this one presents a maximum of sensibilitépOUL' the blue area of the spectrum and a minimum for the yellow and red area: it is thus necessary to employ a bain..sensibilisator (solution of cya-, nine with 1: 25000). The développeml-MT is carried out either with revealing the addes, or with the reducers alcali~s, or better still with both, by employing them su~cessivement. One starts by revealing the image with a pyrogallic acid solution it. 1 per 100, then one, _ termine' with a pyrogallol solution slightly alkaline, container unpeu of potassium bromide. The fixation takes place in a soda hyposulphite bath it 15pOl~r 100: the layers being very thin, it - - quickly is finished, If one does not fear to prolong the exposure time, one can be useful oneself of the process on albumin likely to give good results: * Albumin 1. * Iodize potassium 10. * Iodine 0", 5 The potassium iodide is dissolved in some water drops, then iodine is added there. The whole is then thrown in the albumin, which one beats in snow. After Duit of rest, one elutriates the liquid in a test-tube. Using a pipette, one takes albumin in this test-tube with the average part of the liquid, which is always clearest. The extension of albumin on the ice is extremely difficult. One sel'. transfered oneself of a spinner or a centrifugal apparatus. ~es ices, once albumenized, is preserved indefinitely. One sensitizes them in the following bath: *Eau, . ".'. , l00t'C' *Azotate d'argent cristalllsablc 6,. *Acide acétique cris talUsablc.. .. ... .. . .. 12 The nitrate solution fiItrée is versed in a vertical basin out of glass, in which the ice is plunged without downtime, using a hook also out of glass. The layer of albumin, qui' was originally transparent, becomes slightly tender offer line. Generally, one lets it remain uansle bath of money only ten seconds to one minute (1). To wash then and dry with, the shelter of the light. To expose to the darkroom, the indications of Mr. Lippmann. The installation is extremely long and can only with difficulty be specified. Procèdé Lippmann with isochromatic plates. - As of May 189.2, Mr. Lippmann supplemented first stated that it had made his discovery, by the communication suivante': "In the first communication that I had the honor to make with the Academy on this subject, I said. that the sensitive layers that I employed then lacked sensitivity and of isochromatism, and which these defects were the principal obstacle with the application of the method which I had imagined. Since then, I have réussi to improve the sepsible layer and, although it remains still much to be made, the new results are rather encouraging pour' that I allow myself to make share with the Academy of it. ), On layers of albumino-bromide of money, made isochromatic by the azaline and cyanin, I obtain very brilliant photographs of the sp' êctre.. All the colors come at the same time, even the roug(;1, without interposition of coloured screens, and after an installation comp' small channel between five and thirty seconds. "On two of these stereotypes, one notices that the colors, seen by transparency, are very definitely complementary among those which one sees by D inflection. The theory indicates that the colors COM -, posed that cover the natural objects would have goes laughed el' Photographs some as well as the simple lights of the spectrum, It was not less necessary to check the fact in experiments. The four stereotypes which I have the honor, to subject àl' Académie represent rather various objects accurately: a stained glass with four colors; a group of flags; a ' orange dish surmounted by a red poppy; a multicoloured pel' "roquet. They show that 10 modelled is returned at the same time as the colors, "Le~ flags and the bird required from five to ten minùt, are of installation to the electric light or the sun. The other objects were made after many hours of installation to the diffuse light. It remains, therefore to make still much before returning the procédépratique. " Pl' océdé Lippmann ù the gelatine bichJ' oJJwtée. ~ One knows that a layer dries of albumin or of dichromate gelatine is modified by the light: the organic matter, becomes less hygrometrical. , the majority of the processes of photomechanical impression employed in industry are founded on this, action of the light ' A layer of albumin (or gelatine) bic.hromatée, run and dried on glass, est' exposed with the darkroom, leaned with a mirror of mel' cure. It is then enough to put it in water for voi; apparaitre colors; this washing it it pure water, by ènlevant bichromate, fixes the test at the same time as it develops it. The image disparait when one dries the plate, to reappear each time that it again is wet, The colors are very brilliant; one sees them under all the incidences, i.e. apart from the incidence of the regular reflexion. By looking at the plate by transparency, one clearly sees complementary colors seen by reflexion, The dichromate gelatine is composed in the same way, except that the colors appear in their place, not when the plate is wet into full, but when one, makes it slightly wet into blowing to his surface. The theory of the experiment is easy to make. Comme' in the case of the sensitive layers containing a money salt, the mirror of mercury gives place, during the installation, with a series of maxima' and minima of interferences. The maximum ones only impress ln. layer, which takes, pn.r continuation, a In.mellaire structure and is divided into layers alternatively inflatable and ' noninflatable pn.l' the en.u. ' fant that the plate is dry, one n.perçoit pn.s of image; but, as soon as water intervenes, it!! left the layer not impressed soak some; the index of refraction varies consequently periodically, in the thickness of the couc, He, just as the capacity reflectors, and the coloured image becomes visible. When albumin is employed, it fn.ut to extend a layer of this liquid on glass, ln. to make dry and, moreover, to coagulate it by bichlol' RUE of meroure before plunging it in bichromate of potasse', Without this precaution, not impressed albumin would dissolve at the time of washing it it pure water. One can pass to bichloride mercury either front, or after the plate received the luminous inlpression (!). These di\' strops experiments of Mr. Lippmann has excited at the most point the interest of the erudite world. Collected initially it it foreign with a skepticism not disguised, they forced the attention by their highly scientific character and the assumptions that they confirm. Also incredulity it made place it fills with enthusiasm it, and one currently sees eminent physicists and skilful experimenters to compete of zeal to improve the obte- results. naked. It would be unjust not to note that, thanks to the contest of these goodwills, in particular of France and Germany, the question notably progressed. We quickly will review the various methods suggested either like alternatives, or like improvement a.u procédéLippma.nn. With the first category are attached all the tests which derive more ' or less directly of the ancians experiments C Becquerel and Poitevin. Their list would be long. It suftlm to quote quelquesuns of it: those C I\:rone, of Saint-Florent, etc. The future does not appear to be reserved to them. With the second category, i.e. it that of the improvements. are attached the processes of MISTERS Lumière, Valenta, ' 1' hwing, etc. C all the eXj)él' imentateul' S which are occupied of this delicate question, ' i\I. Louis Lumière is certainly that which innovated with the most bonheur~ M~I. Valenta and Neuhauss also succeeded in it obtaining good photochromies, as the success of the illustrated conferences of pro attests it, jections which they gave in Vienna and ù. Berlin (1). , ====Krone Procedure==== In the current of the year J8D2, Mr. Krone makes a success of ù. to obtain color tests without the use of a reflective mercury surface. To this end. it uti!is' has the reflexion back luminous radiations on the su~face inter~e C the plate glass, to form the necessary fringes ù.la reproduction of the colors. To increase the action of glass, it recouv~ait 13 plate of a tight black velvet against the layer, of albumin. The colours obtained by this process are less beautiful than those that-gives a mercury mirror, but they are perfectly perceptible; The theory of the phenomenon is rather complicated, because diffraction should certainly be fairei~tervenir;: Since then, read. Krone(2} consigned the result d~ its experiments in a Work where it exposes aùssi work of its precursors. In his opinion, the condions necessary to obtain a correct reproduction of the colors are determined by the following observations: *l0 It is essential that the sensitive layer is perfectly homogeneous. *20 When the sensitive layer exceeds a certain thickness, the colors are denatured or disappear completely. Everywhere where a grain of dust is, one observes this phenomenon in all his variations. *30 the formation of the colors corresponding exactly to those of the original depends on the following circumstances: . (has.) Proportion exact and difficult to determine sensitizer compared to salt haloYde of money, this last being in the layer with the ét' At of extreme division; *(b) Of the degree of heat to which drying takes place; *(c) Of the duration of the installation and I intensity of the lnmière; *(d) Of the development. When one or the other of these conditions is not filled exactly, one observes the abnormal production of coulel~r~ false or the disappearance of couleurl! true. *40 the percentage of moisture of the plates moditie D sultat, while varying the colors *50 In the case of the photography solar spectrum, height of the Sun above the horizon intiuo on the value of the colours obtained: IG 1"PART. - OPERATIONAL PROCESSES. *60 actinic intensity of an electric arc lamp whose positive charhon is placed at 36 ====has, - Process of Saint-Florent ('),==== An ordinary plate with money gélatinobromure having been exposed under glass coloured with the rays di-. rects of the sun during fifteen to sixty minutes, then fixed without development and washed after fixation, reproduced the colors of the original if one placed SUl' it will tra -. jet of the pencil of light an orange screen-fillre, the colors are visihles by reflexion when HT layer is wet. Here the talk of the procedure followed by Mr. of S~int-Florent, such as it gave it in a communication made to the meeting of the French Company of "Photography of December 2, 1892: "a plate with gélatinobromure is exposed to the sun behind a yerre colored (glass of magic lantern) during a time which can vary fifteen minutes It one hour. With leaving the frame, the plate is not pas dé\' eloppée, but Ilxée immediately in a concentrated hyposulphite bath and washed with the greatest care "In front of colored glass, one had care to place a screen out of orange glass. Qn can also make use of the successive screens indicated by Mr. Berget (red, green etbleu). "At leaving the last bath of washing, the test has by réllexion the colors of the model. These colors, which are very low, but nevertheless distinct, disappear almost completely when the ice is dry "Lcs colors are more sharp and the larger speed if, before the exposure, one plunges the ice to gélatinobromure in a silver nitrate solution to iD for approximately 100, ' added with alcohol in a strong proportion. These plates, without any washing, preserve their sensitivity long enough. *This sensitivity increases pal' the addition with the bath of one or two mercury nitrate drops by 100cc of solution. *This last bath Sc does not preserve. *U The colors by transmission are generally complementary colors seen by reflexion. *Please notice that I do not develop the tests, and that there is no mercury mirror in the experiment which I have just described. The reflexion incidental rays is done about normally on a reflective surface, which is most probably the posterior trauche of the significant substance and not that of the ice. D Principal conditions of the so remarkable experiment of Mr. Lippmann trouvent.donc with louse close realized, and the phenomena of interference pro' are duisent in about similar circonstances'. D All handling is done, without any in convénient, with a weak diffuse light. D The orthochromatic plates of Mr. Lumière give good results, but I could not encoro pass to me from screen. D If, garlic place of plate to gélatinobromure, one employs plates with the gélatinochlorure (Perron mark), one often obtains tests whose eouleÙrs are (Pa!, reflexion) complementary of those of the model. I could not, until now, to return to me account of this anomaly "In the meeting of the 7 aoQt 1891 (Bltllcti1~, of September), I made known the tests that I had made by means of the dichromate gelatine appliquée.sur polished metal plate. D I come from the r.épéter with albumin. D The results obtained are encouraging, but still quite incomplete. The colors have a great glare, a true metallic lustre; they my Trent only when the plate is dry, contrary result with that which has just obtained ~f. Lippmann in CUAI'. 1. - PRI::PARATIOll RE I.A COUCIIE SE"Slnl.E. IV brilliant experiments exél:utées by means of the dichromate albumin applied to glass "It is as extremely singular as the tests with gélatinobromure that I have obtenuos are visible (I speak about the colors) only when the wet ice ost, whereas 1\ 1. Perhaps Berget, in its Works and dllns its conferences, expressly known as that the colors se' show only when the ice is completely dry "That is due with the suppression of the révéllltour in the process of which I have the honor to return account to you, suppression with which I was brought in répétllnt the famous experiment of Yung." I have fllit some essllis by means of the black chllmbl' E; one obtains many épl' euves stained glasses and landscapes, m~is it is very long, and the visible colors son' tà sorrow. One thus needs still well DCS experiments before arriving to the complete solution of the major problem by the method mentioned above "to preserve the color tests, I imagined a kind of vertical basin whose former face is out of glass. This basin is full of slightly carbolic water, and one places the test there on black bottom J the face glass is framed and presents the aspect of a genuine framework of photography. "By finishing this long letter, I believe duty to announce you a rather singular fact: "Hunt, about 1845, managed to print the solar spectrum with its couleurd, but the colors disappeared with the fur and measurement which the sheet dried 20 1"PART. - PROCESSES OPÉRÂTOIRE. of paper on which it operated. You will find, in all its details, this experiment in the Roret Handbook, 18G2, tom~ II, page 297. D What proves that there u' is nothing again under the sun ".' . . Another curious fact, also announced by Mr. de Saint-Florent is as follows: "I arrived, written ~r. of Saint-Florent, fi to produce color tests by means of iron salts to the maximum. "I employ the bath indicated quite simply, a long ago, by Poitevin: *Water. 100" *Perchloride of fcr 10 *tartaric Acid 5 "As I did not have a plaqnes with the simple gelatine. I took the pl!\ques ones with the gélatinobromure of which I removed salt haloid of money to average C hyposulphite "Aprè.s of the lavag' are neat and a complete drying, the plate, whose gelatine became insoluble, is exposed behind glass colored pendant\.un rather long time. After the exposure, one washes it it tepid water; the insolated parts became more or _ less soluble, and a épl' euve is obtained that devnnt should be dried quickly fire. "When the image is dry, it presents neck their light, among which the red, yellow and breadth ert. The purple ones and the blue ones are it pains visible. "These colors are not seen under all the incidences; they should be observed under the same conditions as in the first experiments of Mr. Lippmann. "I also obtained turns dichromate color with Ia.gélatine applied to glass. One develops with the cau cha.ude. The colors are shown as in the experiment above. "It appears certain to to me that with a mercury mirror the results must be infinitely better (1)". In another communication at the French Company of Photography, Mr. de Saint-Florent thus summarizes the results of his experiments: 1. One takes a paper with the chlorl1l' E of built-in money daus a vehicle like collodion, the albu~ mine, the gelatine, etc. Papers with the celloïdiJ1c are excellent "One exposes this paper to the diffuse light until the moment oil it starts to show traces of metallization: One then applies it, without no preparation, in a positive frame, behind glass colored "At the end of several hours of exposure in full sun, one obtains a positive image which presents at little p1' ès, on a a little dark bottom, all the colors of the model. D 20 a paper sheet to the gélatinochlorure (money excess) are exposed during several hours Photo-gazette (t), 1893, p; 55. behind glass of magic lantern and place to a negative test presenting gives some traces of colors. The image changes, it is -âdire that it becomes positive, if, to leaving the châssi~, one exposes it to sunlight. The colors already a ' little appa.rgraft become more sharp and those which were latent. show souventa.près a duration more or less prolonged. The greens and especially the ja.unes come very with difficulty "These. tests have a certa.ine stability, ma.is they are not fixed ". With papers with collodion-chlorùre.. (celloYdine, etc), the speed is larger, and the ve1' ts and the yellows come better, if one applies to the test, av' ant its exposure on the ground have, a little varnish to terpentine (very diluted). " ====4. Process CH R. ThwJng==== Mr. CH R. ' the hwing, with an aim of increasing SEN. sibility of the plates, A. proposed into 1892 of sq;bstituer money collodiobromure to albuminiodure. . formulate indicated is the suiva.nte: \. *Cadmium Bromuro,; . 25" *Alcohol Acid 250" *chlorhydl' Ique... . . . . . . . ... . . . . . . . ... ... . . 5 One mixes Sec this solutionà, 40cc of ether and one adds 2sr pyroxylin' E, then, drop by drop, une' alcoholic solution C nitrate d~argent to 10 per 100. It is necessary to extend. the mixture on the plates before it was transformed into emulsion: the sensitive layer is blue pale, slightly opalescent. ====6. -:Procédé Kltz (').==== Mr. Kitz announced this fact that certain positive papers, Obernotter paper with money gélatinochlorure (of Emile Buhar, in Mannheim) for example, are likely to reproduce the colors, when one isolates them under coloured glass. The polychrome images obtained cannot be fixed. It is necessary to bring closer this fact coux published by Mr. de Saint-Florent. This experiment is attached rather to old ~é thodes of Becquerel and Poitevin. The colors are né.anmoins due probably to a phenomenon of interference. ====6. -:Procédé Lumlére.==== As soon as the experiments of Mr. Lippmann had been. published, ' MISTERS Auguste and Louis Light, of Lyon, undertook to repeat them. Of all the experimenters who la.ncèrent themselves in this way, they were more ' happy;! because they not only succeeded to reproduce the colors of the spectrum, but they were able to improve the process and to make it practical in a cèrtaine measurement. Btant given the importance of the results to which they arrived, - as the splendid polychrome stereotypes testify it which one could see in various exposures or conferences, -- we will completely quote their first communication made it it French Company of Photography on Celt question, on May 5, 1893. "As of the début' of our experiments on the Photography of the colors according to the method, if remarkable, imagined by 1\1. professor Lippmann, we had proposed to make c:onnaitre the process which had led us it it obtaining, of the tests which we had presented at the French Company of Photography, but the irregularities quç we note then retained us and we have préféréattendre a(ln to give indications pr6cises allowing to surely arrive it of good results. ) That us re\' endiquer is allowed, very of A., edge, priority on process which Mr. Valenta made known, of Vienna, and who consists it mélangér, to obtain emulsion, if as well is as one pJisse to thus call the preparation obtained, deux' gelatinous solutions, one containing ùn soluble bromide, -, the other of silver nitrate. NoÙs, indeed, made connaltre, in one, communication on March 23, 1892, it it Company of industrial Sciences. , of Lyon, the method which we follow then. and which, CllAI'. 1. - the nÉI' AnATlO~ Of COUCllE SENSIULE. 25 as you will see it, differs very little from that in diquée by this expérimentateur' (1). "the following formulas were established empirically, that goes without saying, but we offorcés ourselves, in the very many experiments which we made, to proceed with method, never not changing, at the same time, which only one of the constituent elements, as well with regard to the emulsion as in what looks at the revealing one. From where the quantity of tests required and the extremely long duration of time that we have dCl to devote to it "to obtain the sensitive emulsion, the following solutions are prepared: With. - distll\ée Water.... "........ 400" GéIMino ' 20 "One adds to the solution C half of solution A, then other half of the latter is addi, tionnée i1 D. One mixes then these two solutions ' 1 ';' (')"Vno solution of 5 pOUl' iOOde gélatino ost addiUonnéo of it. 2 pOUl' 100 C bromuro, chloride, Iodide solublo. Of auiro Pa T, tlno soiutlonsemblable C gelatine is addHlonnce of 2 à3 for 100 C nltrato of argont. It sufllt Llo méiangOl' cos two soluLions for rOl' l1101' I' émulsiou, if it or pout appelol' thus 10 result of the mé~ ' lange, then C dyalisol', to obtain to the preparation of which us uous sommos sorvis." (Accounts I end custom of Socic!te! ielles backs Soioncos ine/usll' of Lvon.) gelatinous by pouring the liquid containing silver nitrate in that containing potassium bromide. One adds then with a suitable coloured sensitizer: cyanin, purple of, methyl, érythrosine, etc, pui~ the emulsion is filtered and couché.e on plates. This operation must be done. with the spinner, the temperature. solution not exceeding 400. "One makes take the layer in frost, then the plates are immersed in alcohol, during a very short time, treatment which allows the complete damping of surface, and finally one washes in a current of cau. The layer being very mean, washing does not require that very little time "This method present, on that indicated by 1\1. Valenta, the advantage of avoiding the enlargement of the silver bromide grain, enlargement resulting from the washing of the mass and the heating required for the recasting, and of allowing the obtentiQn plates of a complete transparency. Moreover, one must avoid, for the same reason, the use of a too great soluble bromide excess, "the plates having been washed suffisammen\.sont put to dry, then, before employment, treated, during two minutes, by the following solution: Distilled water 200"Nilrato of argont il' acetic Aclde.. ... ............... . . ....... ... . 1 "This last treatment makes it possible to obtain images much more brilliant. It increases, moreover, the sensitivity, but rather quickly brings the deterioration of the sensitive layer. One dries again, then the plate is exposed, in accordance with the indications given by Mr. professor Lippmann.)) ====7. - Prooédé Va.lenta.==== At the same time as Mr. Louis Lumière continued in France his remarkable experiments, Mr. E.Valenta.obtenait in Germany of the similar results by not very different means. It is right to note however that the priority belongs incontestably to the young French scientist whose photochromies had been presented at the Company industrial Sciences of Lyon since 1892. Mr. Valenta exposed làrésultat his research in a certain number of German periodicals (Photographische Çorrespondenz; Photographisches Wochenblatt), and in particular in a Work which it published on this question: Die Photogl' aphy in natiirlichen Farben CHalle. a. S., KnapPi -1894). . To obtain the continuity and the homogeneity of the layer, - essential conditions of success indiquées' by Mr. Lippmann, - Mr. Valenta observes that all the efforts must tend towards this goal: to prevent the emulsion from mùrir. Ammonia, heat make mflrir the emulsion and increase its sensitivity, but also the particle sizes: they will thus have to be avoided. One will prepare two solutions with also low moderated ture that possible (300 to approximately 350), one being composed of the quantity necessary of silver nitrate, the other of the gelatine and bromide, then one will pour the first in the second: no precipitate is formed, the solution tt' ouble not, but becomes slightly opalescent; it should be employed earlier ~e possible, tout' delay supporting the production of a coarse grain. Here a' elsewhere the exact formula, fruit of patients research. on behalf of the author: A. Gélatine 10" Eau. .. .. .. . .. .. ... ... .. 300" Azotato d'argenl., . ... , .. . .. . 0 G' B. Gélatine 20" Eau .. . ... .. . . .. .. .. .. .. .. .. .. ... . .. . ... 300" Bromure de potassium .. 5., These solutions are cooled it 350 C; then, in the obscure laboratory, solution A is slowly versed in the solution B, while stirring up constantly. When the mass is quite homogeneous, one plunges it in approximately was of alcohol with 90 per 100, then one stirs up it with a rod of glass until all the bromurée gelatine is adherent for him. One carries out then washing as for an emulsion ordinkiro, i.e. one divides it into menus fragments which one places a few minutes in running water. 3rd: - well washed milking is then molten at as low temperature as possible in a bell jar; one adds the quantity of water necessary to reform the primitive volume of 600", then one filters and, if there is place, one incorporates with the mass the dyes necessary to obtaining orthochromatism. If one wants to avoid this last operation of fusion of the mixture, one can adopt the artifice indicated by Mr. Lumière. The emulsion is not precipitated, but one proceeds with spreading immediately after the mixture of the two solutions A and B. The plates are placed on a quite horizontal marble support until. what the sensitive layer is taken. One then washes quickly approximately fifteen minutes with running water, Co which is enough perfectly to remove all soluble salts. Da.ns all the cases, the emulsion must be filtered before being wide. To this end, one will be useful oneself with a\' anta.ge of a funnel whose bottom is furnished with a glass wool plug or better still of hemp ita.lien than one will have beforehand made boil 3.Yec a solution of very wide potash, then washed with large water. N is necessary of prendr.e guard, when one proceeds with the spreading of the emulsion, quela sensitive layer does not exceed a certain thickness. Mr. Valenta noted that the best results are obtained with leseouches thinnest. If there is not the practice of this kind of operations, one could be useful oneself of a tOllrnant plate on which one will place the ices: grace it ]0. centrifugal force, the emulsion will be distributed amusement in all the directions, One will observe moreover than, lol' S of the preparation of the plates, it is essential to subject them to an alcohol bath diluted before final washing I if one omitted this precaution, one would notice that the sensitive layer is covered small bubbles of air. who adhere to the emulsion and prevent consequently water from producing its action. When the sensitive layer is dry, one will thus immerse the plates in a cuv.ette containing wide alcohol and one will agitate the liquid until the whole surface is well wet and which all the bubbles disappeared. One will finish by an energetic washing under an apple of watering-can, then in running water (twelve to fifteen minutes) and one will obtain perfectly transparent ices thus, presenting by reflexion a light opalescent colouring. The plaSlue is then ready to receive the impression}umineuse one, If one had suddenly exposed it to the ammoniacal vapors, the sensitive layer would bleach quickly in consequence of the enlargement of the grain of the emulsion. One could not think any more it of obtaining the reproduction of the colors. Mr. Valenta noticed that the emulsions with the money chlorobromide gave results more brilliant than those to bromide, It indicated, for this purpose, the following formulas like most practical: A. Water.............. ... ....................... G 61allne..... . ..... ..... ... ... ....... ....... D, Water..... Lunar caustic.. . . ... ...... C, Water.. . . . . . . . . ... ... . . . . . . . . . . . ..... . . . . ... Bromide ùo potassium...................... Chloride ùe sodium.................. \' 200 " 10.' 15" 1 GI',5. A. Eau.. .. .. .. .. .. .. . .. . .. .. .. .. .. .. .. .. .. .. .. . G 61allne .. .. . . .. .. . .. .. . .. . .. . .. .. .. . .. .. ... D, Eau ..... Azotate d'argent .. . . . .. . ... ... C, Eau.. . . . . . . . , . . .. . .. . . . . . . . . . . . . .. .. . . . . . .. . Bromure ùo potassIum...................... Chlorure ùe sodium... ............... 15" 081',35 0",35 One divides A in two equal parts, one that one pour in B with 3: 0 or 400, the other in G One mix well and one pours B in C. A. Water 300"GélaLine 10. Silver nitrate... G N Eau 300"Gelatine..... 20. Bromide of potasRlum 2, -, 4 Chloride of sodium..... L,5 cdc666e1c3c28b3c3fdc1422caf750814eef000c 6 44 689 44 2006-05-07T21:51:16Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 120 489 120 2006-05-07T21:57:24Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 83 783 83 2006-05-07T22:23:26Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 119 487 119 2006-05-07T22:39:21Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 453 1056 2006-05-08T13:55:00Z Colin Kaminski 0 /* Tips */ wikitext text/x-wiki Painting the back of a hologram black is a great way to enhance the contrast of the image. Care must be taken to not destroy the image while painting it. (Do not try this before sealing DCG holograms!) ===Tips=== *Paints that dry too quickly can damage some emulsions by shrinking them and making a crazed glass pattern. *Krylon Ultra flat black can dry very quickly if not applied in very thin coats. *Krylon gloss and flat seem to work well. *Make sure to protect the front of the hologram while painting. *Paint the edges if you are not going to frame the hologram to keep stray light from entering. *More thin coats is better than one thick coat. *Don't try to rush the drying. *Examine the hologram from the front after painting with a light source behind it to look for any thin spots. 4e065bda67229d7022fa49e7b87ee6dbf8118e68 0 228 303 2006-05-09T11:37:46Z John Pecora 0 /* Some Uses for Everyday Items in Holography */ wikitext text/x-wiki ==Some Uses for Everyday Items in Holography== by John Pecora Here are some tips for saving money on ‘lab’ equipment. It is surprising how many everyday objects can be used to good effect in holography. These are just suggestions. Please remember that it is your responsibility to pay attention to safety, and use common sense. *Heating pads used with three or more settings can be used as adjustable heaters for processing trays. Simply put the heating pad under the tray and turn the pad on to the desired setting. *Black foam board can be used for blocking stray light. The type that is black throughout is best as the edges stay black even when they are cut. This material can also be used for making an iris. *A shutter can be made from most old 8mmmovie cameras. They have a low voltage electric shutter. Remove this unit and set up a circuit with the original voltage of the camera, and a switch. *A thick piece of glass, 1/4 inch or thicker, can be used as a beam splitter. Using the thick piece of glass allows a small piece of electric tape to be placed over the glass to block the secondary reflection off the back. *Sandwich boxes can be use as processing trays and also as storage for the chemistry without having to pour the liquids back into bottles after each session. They come in many sizes and shapes with airtight lids. Store sealed containers with chemicals in a dark, dry, cool place when not being used. *Rubber inner tubes can be used as the dampening mechanism between a holographic table and the support legs. *A slab of granite can be used as a holographic table. *Most old overhead projectors contain large front surface mirrors and large Fresnel lenses. They can be purchased at yard sales and flea markets for just a few dollars. *Most photocopiers and fax machines contain front surface mirrors. *New Jefferson Nickels have a weight of 5 grams and new Lincoln Pennies have a weight of 2.5 grams. Standard paper clips have a weight of 1 gram. To verify the weight of the paper clips put a nickel on one side of the balance and find 5 paper clips of the same size that equals the nickel. These can be used on a balance for measuring out chemicals. *A hair dryer can be used to dry a piece of holographic film or plate after processing. Drying intensity and heat is variable with very inexpensive dryers. *Polarizers can be found in polarizing sun glasses. These can be used to adjust the intensity of polarized laser light by inserting the polarizer in the beam path and rotating. They can also be used to check the polarization of light at different locations in an optical set-up. *Two pieces of window pane glass and binder clips can be used to sandwich a piece of holographic film. This will hold the film rigid and flat. *A microwave can be used to warm the deionized or distilled water needed for mixing up processing chemistry. But please be careful to keep chemical-contaminated containers separate and secure. One method is to heat the water in a clean container in the microwave and then pour it into the chemical container for mixing, always keeping the clean container free of any chemicals. *Two-part, fast-hardening epoxy is great for securing two pieces of metal without the need for drilling and tapping. This also allows easy disassembly with just a small sharp blow to one of the pieces. *A pinhole can be made by sandwiching 5 or 10 pieces of aluminum foil together and poking with a pin while the pile is on a hard piece of rubber. Each piece of foil will have a slightly different size of pinhole. *Automobile windshield wiper blades can be used as a squeegee. If you epoxy two blades to a pair of scissors then, when the scissors are closed 3/4 of the way, you can squeegee both sides of the film at the same time. For plates this is not necessary as you can do one side at a time with a single blade. *Clothes pegs on a line can be used to hang up films to dry. After clamping the film at two corners with the pegs, clamp two more at the bottom corners as weights to keep the film straight while drying. *Dishwasher drying agent can be in place of PhotofloTM in the final rinsing bath. Use an agent that does not have fragrance and, preferably, one that is clear. *Sodium carbonate can be purchased cheaply as a chemical for increasing the pH of swimming pools and spas. *Sodium bisulfate can be purchased cheaply as a chemical for decreasing the pH of swimming pools and spas. *Sulfuric acid can be purchased as car battery acid. Most formulas call for concentrations that are lower than that sold as auto battery acid. *Black Sanford Sharpie markers, which come in different sizes, are ideal for blackening optics, mounts and anything small you want to reduce reflections on. They are permanent markers that write on almost anything. *Paper MateTM liquid paper correction is great for painting objects for holography. It dries to a flat white and diffuses the light very well. *A disposable shower curtian works well as a dust protector for a collimation mirror. fe6b24a607672d1089e351c9f6889efc64c58fb7 6 90 811 90 2006-05-09T22:56:45Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 537 1224 2006-05-10T14:02:44Z Colin Kaminski 0 wikitext text/x-wiki Colin, I don't know how to delete and uploaded file. So I had to re-upload this one and named it "PreScoredCoatAtOnce2.JPG". Could you delete the original named [[Image:PreScoredCoatAtOnce.JPG]] and explain how to delete an uploaded file. I do not want to waste space on the server. John P. ---- Hi John, if you have the image showing, click on the image. There is a button for deleting it. I don't really know why we can save a new image to an old name, it is not a reported bug with this version. It likely has to do with the security settings... BTW, nice work! I deleted it... 289dd642d3cb24ccb32f7bfbfc056273103f3c03 6 13 883 13 2006-05-12T11:21:03Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 536 1222 2006-05-19T00:29:33Z Colin Kaminski 0 wikitext text/x-wiki I am not sure but I believe the Rain-X was used just on the surface of one of the pieces of glass to allow the emulsion not to stick to that piece of glass. I believe if you treaded both peices of glass the emulsion may lift off the piece of glass it was meant to stick to. ---- Rain-X will not stick to gelatin at all. I believe it is silicone. It is important to only coat one side. 7a448fa172449b02902444e0a451e93f75a674f9 1 538 1226 2006-05-19T00:33:10Z Colin Kaminski 0 wikitext text/x-wiki I am not sure why you had the first measurements of the red and blue beams at 4 instead of 4.5 thus indicating different path lengths compared to green. I matched them to the diagram (4.5) and all paths are the same length again. Thanks for taking the time to review it though. ---- It did not really bother me as in the real world sometimes you have to accept a beam placement that will fit on the table and not really the best beam. Thanks for the work! 7eaf94811f8f6d1dc385b824423ed3bd689e34fe 6 14 885 14 2006-05-19T16:59:16Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 15 887 15 2006-05-19T17:23:24Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 440 1030 2006-05-19T17:26:48Z John Pecora 0 wikitext text/x-wiki In the illustration below the laser beam exits the laser in the upper right. It is then split by a beam splitter. Following the red path (red only for distiction and no correlation to laser wavelength) you can see it travels 3+14+15 = 32inches to the film plane. Now following each of the black paths from the first beam splitter you can see that the beam that illuminates the back of the object travels 14+2+8+8 = 32inches, as does each of the other paths 14+2+2+8+6 = 32inches and 14+2+2+2+8+4 = 32inches respectively to the film plane. The benefit of this technique is as follows. If your laser only has a coherence length of 3 inches and it can be deduced that the object is 7 inches deep and only the center object beam is used, only 3 inches of depth will be visible in the final hologram, 1 1/2 inches in front of the center of the central object beam and 1 1/2 inches in back of the center of the central laser beam. With the configuration below the front beam not only reaches to the front of the object which is only 1 inch away from the center of the front beam but also reaches 1 1/2 inches toward the back of the object at which point 1 inch back the second beam is reaching and the coherentness overlaps. Thus coherence limitations are maintained for each of the three "Volumes" of the object. The expanded reference beam is not shown for clarity. The coherence "Volume" is show with the object beams by only showing that part of the expanded object beam. [[Image:TransVolume2.JPG]] 9dba22f9dd869f0deba17b5f20223f31ac5623ec 1 542 1234 2006-05-19T22:29:56Z Colin Kaminski 0 wikitext text/x-wiki I am sorry, I could not for the life of me find where "Path Length Matching" was linked so I included it here. Feel free to move it to a more appropriate location if you find it more helpful. JohnFP ---- The cool thing about the wiki is you can link from anywhere and everywhere! ---- a499200e3a33959dba2909745df31c05c1d39428 0 504 1158 2006-05-20T02:35:08Z Colin Kaminski 0 Moving out the Silver recipies wikitext text/x-wiki [[Silver Processing Formulas]] 2765fe4f109324532f33db373fa351134154da84 6 23 931 23 2006-05-21T00:12:32Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 24 933 24 2006-05-21T00:13:13Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 596 1342 2006-05-21T00:16:25Z Colin Kaminski 0 wikitext text/x-wiki [[Image:YDenisyuk.jpg]] Died at the age of 88 in May 2006. Yuri Denisyuk invented single beam reflection holography. ===A Memorial by Ed Wesley=== {| |[[Image:YDenisyuk2.jpg]]|| “Now maybe the girls will notice me!” quips Yuri Denisyuk, proudly displaying the Cyrillic Danger: Laser Radiation sign presented to him by the local Coherent Laser sales rep at his first visit to Lake Forest College in 1989. This is my favorite image of one the great gods of Mt. Holympus, personified as everyone’s favorite grandfather with a wacky sense of humor. After all, it was a science fiction story that inspired him to invent his own style of wavefront reconstruction! |} 23547694fa01e4436246f818676e4a704e37c097 1 539 1228 2006-05-26T01:56:25Z Phil Edelbrock 0 thoughts on costs vs. technology at smaller scales wikitext text/x-wiki I might suggest that on smaller scales, the distiller option might be cheaper and provide a better solution to, say, charcoal filtering? For example, I bought my 1-gallon distiller (on super-sale) for about the cost of 3 Pur charcoal filters. Granted, the power usage of the distiller is an additional cost, but I wouldn't think it was significant? Of course, $50 or $100 can buy a lot of distilled water at the local mega-mart, too! 3da4b9475901b88f33ed8540f3a895b0ca39909c 0 276 399 2006-05-26T15:02:41Z John Pecora 0 wikitext text/x-wiki Holography #'''Holograms''' - [[Holograms|Hologram definition and types]] #'''Model Building''' - [[Making Hologenic Objects]] #'''The Lab''' - [[The Lab|Setting up your lab]] #'''Equipment''' - [[Equipment|Equipment used in making a hologram]] #'''Setups''' - [[Setups|Setups - different holographic geometries and configurations]] #'''Computer holography''' - [[Computer Holography|Computer Holography]] #'''Interferometry''' - [[Interferometry|Holographic Interferometery]] #'''Holographic Optical Elements (HOE)''' - [[Holographic Optical Elements|Holographic Optical Elements]] #'''Tips and Tricks''' - [[Tips and Tricks|Tips and Tricks]] #'''Troubleshooting Holograms''' - [[Troubleshooting Holograms|TroubleShooting Holograms]] #'''Displaying and Illuminating Holograms''' - [[Displaying and Illuminating Holograms|Displaying and Illuminating Holograms]] #'''Photographing Holograms''' - [[Photographing Holograms|Photographing Holograms]] #'''Shop Basics''' - [[Shop Basics|How to use shop tools to make mounts and hardware]] #'''Holography Glossary''' - [[Holography Glossary|Holography Glossary]] #'''Books''' - [[Books|Books on Holography]] #'''References''' - [[References|References]] c08819ceedcae219a22a60a7b3a203c1e73deb57 1 544 1238 2006-05-26T16:58:56Z Colin Kaminski 0 wikitext text/x-wiki This should probably be included on the links page. [[Holography_Links#Links_to_Holography_Supplies_and_Tools]] ---- Ok, should I reorg the section in this link by item, then put the suppliers underneath? That way one that is looking for a "front surface mirror' for example can find it more easily. John ---- That is a good idea. Also the descriptions are very brief now. Perhaps we will have time to expand them... 8211e6ccb402748a9056794fea357704d62530a2 1 543 1236 2006-05-26T17:13:41Z Colin Kaminski 0 wikitext text/x-wiki Hi John, I was wondering if this should all be on this page? It would be easier to compare the differences and learn if they were all on one page. Colin ---- Feel free to reorg as you wish. John ---- How is that? C 7d7d6229aabbc1d7886d45f73aacb6c0f2c51bb7 0 503 1156 2006-05-26T18:32:20Z Colin Kaminski 0 wikitext text/x-wiki Described here are sucessful chemistries to use for each qualifying film for a particular type of hologram. For specific formulations look at [[Silver Processing Formulas]]. ===Single Beam Transmission - Film vs Chem=== ====PFG-01==== For low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up. (Ed Wesly) ===Single Beam Reflection - Film vs Chem=== ====PFG-01==== (Ed Wesly)- Replay in the same wavelength use CWC2 developer with PBQ rehalogenating bleach (Ed Wesly)- Replay is color shifted use Pyro or CWC2 developer with Dichromate reversal bleach Replay in same color use JD3 - Integraf Replay shorter use JD2 - Integraf ====PFG-03==== (Ed Wesly)- Replay is same wavelength use Slavich Hardener with G2 Developer and Slavich Fixer ====BB640==== (Ed Wesly)- Replay in the same wavelength use Pyrogallol based developer with Rehalogenating bleach ===H1 Transmission - Film vs Chem=== ====PFG-01==== (Ed Wesly) - Replay in the same wavelength use CWC2 developer PBQ rehalogenating bleach Another case is for low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up (Ed Wesly). ===H2 Transmission - Film vs Chem=== ====PFG-01==== Another case is for low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up (Ed Wesly). ===H2 Reflection - Film vs Chem=== ====PFG-01==== (Ed Wesly) - Replay in the same wavelength use CWC2 developer PBQ rehalogenating bleach (Ed Wesly) - Replay is color shifted Pyro or CWC2 developer Dichromate reversal bleach ====PFG-03==== (Ed Wesly)- Replay is same wavelength use Slavich Hardener with G2 Developer and Slavich Fixer ====BB640==== (Ed Wesly)- Replay in the same wavelength use Pyrogallol based developer with Rehalogenating bleach b5cb77df2fb9ff0be3715c637250420362a0d19c 0 465 1080 2006-05-27T21:55:30Z Colin Kaminski 0 wikitext text/x-wiki POPULAR OPTICS by Sam Brown, Edmund Scientific Company, Barrington, New Jersey, 1974. “This book is a reprint from several smaller booklets published by Edmund Scientific Co. during the past fifteen years. Most of the standard optics specified are currently available, but some military surplus items are long gone. Where practical a substitute lens has been mentioned - in all cases the current Edmund catalog is your guide.” From the contents page. It’s 30+ years later, but still some of the same optics are available. And there still is a need for a real how-to book on building simple optical devices like overhead projectors, opaque projectors, telescopes, collimators, magnifiers, etc. One of the great features of this book are its formulae. They take the Simple Lens Formula and break it into all its permutations. For instance, if you know the object distance and focal length for an imaging scenario, you can find the magnification by looking up the appropriate formula and plugging and chugging. They also give examples of practical calculations for all formulae, using whole numbers so that it is easy to see the math in action. I haven’t seen it in the Edmund catalog recently, but who knows if there isn’t a box of them in a store room in New Jersey. $12.95 last list price, but the same information is found in books costing far more! And not as interestingly illustrated! -Ed Wesly 021675a644fcfef49214a2cb1139a7863146ff72 0 231 309 2006-05-27T21:56:26Z Colin Kaminski 0 wikitext text/x-wiki FACETS OF LIGHT Colors, Images, and Things That Glow in the Dark, K. C. Cole, Exploratorium San Francisco, CA, 1980. 107 pp. This is not an easy book to find, but it is worth the effort in tracking it down. Part of the problem is that the Exploratorium, founded by Robert Oppenheimer, has some problems with the US Government, and doesn’t believe in ISBN numbers. The book is basically a catalog of the optical exhibits at the Exploratorium, so it doesn’t read like a normal textbook. It’s hard to know 25+ years later if any or most of these exhibits still exist, but having some familiarity with optics will help flesh them out in the mind’s eye. As an added bonus there was a packet of materials glued in the back cover. A diffraction grating, 4 colors of gels, and a couple of pieces of Polaroid enabled the reader to explore in their own pad the facets of light. K. C. has written a number of other science books, also worth reading. A companion to this volume is Vision: In the Eye of the Beholder, also an Exploratorium Publication. I couldn’t find the list price of the book, but I believe it was under $10 when new. Use this a guideline when looking for copies on-line, because I have seen it at extortionate prices. -Ed Wesly bca16af3156fe87d1e3cddb497e457b37774e61f 0 492 1134 2006-05-27T21:57:35Z Colin Kaminski 0 wikitext text/x-wiki SEEING THE LIGHT Optics in Nature, Photography, Color, Vision and Holography David Falk, Dieter Brill, David Stork, John Wiley & Sons, New York, 1986, ISBN 0-471-60385-6. One of the classic contemporary texts on optics, although it was written before the digital age hit. But the explanations of the classic optical phenomena are right on, with a wacky sense of humor appearing from time to time. Sprinkled throughout the text are TRY ITS which are demonstrations that can be done at home, like making a periscope, a pinhole and an anamorphic slit camera based on 126 film cartridges (no longer manufactured by Kodak since 1999, but still hanging in there thanks to Ferrania of Italy!), conical anamorphic photographs, and many more. There are also PONDERS which really get you thinking about what you just read or experienced. The frontispiece is the first Random-Dot Stereogram (aka Magic Eyes) that I ever saw and they describe how to make one without using a computer! Their holography section is surprisingly quite comprehensive. One of the authors, David Falk, has published an article in Scientific American and devotes a whole web site to nay-saying the basic premise of David Hockney’s book, Secret Knowledge. I myself prefer to believe in Hockney’s explanation of the use of optical devices to render perspective and the fact that the artists kept their tricks secret, knowing what I know about 19th century photographers and 20th century holographers. The only downside of this book is that some of the photographs could have been reproduced better. But there are a lot of them! A must get book for all practitioners of optical arts! It is a bit on the pricey side, but what textbook isn’t in this day and age! -Ed Wesly b8e0f6544623c88c4826d1f502a171dfa4149fae 0 418 986 2006-05-27T21:58:34Z Colin Kaminski 0 wikitext text/x-wiki LIGHT SCIENCE Physics and the Visual Arts, by Thomas D. Rossing and Christopher J. Chiaverina, Springer-Verlag, New York, 1999, ISBN 0-387-98827-0. Like Seeing the Light, this book promises to be an Everyman’s guide to optics with particular attention to the visual arts. (A discussion of whether or not to restore the Mona Lisa is included!) A lot of ground is covered without rigorous mathematics. There is a 61 page appendix of demonstrations that the student can do at home. There are 225 illustrations, about 80 in color. It is a much more up to date book than Seeing the Light, being published more than 10 years later. Photography, holography, and digital imaging each have their own chapters. Both of the authors are Physics teachers, Rossing at Northern IllinoisUniversity, Chiaverina at New Trier High School in a suburb of Chicago. But the writing style is rather tedious, which is probably due more to Chiaverina rather than Rossing, since his Science of Acoustics book doesn’t bog down like this one. Still if you were to have one book on your shelf that answers questions in general optics this would be a good choice. A must get, although pricey! -Ed Wesly 4236504f872c3bf95dad9876cc0601a9ceeca3a6 6 370 859 2006-05-28T02:58:26Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 478 1106 2006-05-28T03:09:30Z Colin Kaminski 0 /* The Reversal Bleach system. */ wikitext text/x-wiki ==The Reversal Bleach system== by Jeff Blyth The most popular form of this type originally used dichromate salt and sulfuric acid. It has been of particular value for use on the AGFA 8E75 HD plates and film because when used correctly it can produce the lowest levels of light scatter. Its popularity for Denisyuk reflection holograms made with 633nm from HeNe lasers also comes from the inclination to hit the fairly elusive yellow replay coloration due to the right amount of emulsion shrinkage. I consider that its chief asset today with finer grain materials available is as a bleach for transmission holograms. It has good printout resistance (i.e. low tendency to darken in ambient lighting over time) and can produce high diffraction efficiency. However for Denisyuk reflection holograms it does not achieve as much diffraction efficiency as can be obtained from a good rehalogenating bleach. People using it have however failed to appreciate that the developer used beforehand should not contain silver halide solvents such as sodium sulfite and urea, and the need for the rigorous exclusion of halide contaminants as discussed in the Theory section. A suitable developer for use in conjunction with this bleach is [[TJ1 Developer]]. The proportions used in the formulation is hugely tolerant of variation. I have chosen to use a lower concentration of dichromate compared to previous publications because it leaves the bleached hologram with less yellow coloration from the dichromate salt and this means less rinsing is required to remove it. Increasing the dichromate proportion will reduce the time taken to bleach the dark silver. I have substituted sulfuric acid with the more manageable solid salt sodium hydrogen sulfate. (This is in fact a semi-neutralized form of sulfuric acid). The basic formula is: *1 g. potassium dichromate (or ammonium dichromate) *10g sodium hydrogen sulfate. *made up to 1 litre in distilled or de-ionized water. The set up should include 2 baths of de-ionized water (DI) as follows: '''Bath 1''' *DI with *4% acetic acid (Acts as a “Stop” to stop developer action) '''Bath 2''' *DI '''Bath 3''' *Reversal Bleach ==Procedure== #After development, a brief 10 second rinse under running tap water then a good rinse in Bath 1. for ~1 minute . #A good rinse in Bath 2. ~1 minute #Immerse in Reversal bleach (Bath 3) and gently agitate until no dark silver remains #Important- after the bleach bath the hologram should be put first back in DI (Bath 2) for ~ 20 sec. before being rinsed under tap. ==Theory== The idea might seem simple enough, after development the developed up silver is dissolved up into the solution and removed from the gelatin film so that then leaves the undeveloped virgin AgBr in the dark fringes to make the hologram. So in effect it both “fixes” and bleaches. The good point about it is that it has a high resistance to printout or darkening in ambient light and can have low scatter levels with holographic plates that do not have the smallest AgBr grains such as the old Agfa material, the lowest scatter comes about provided you understand what you must do to stop any soluble halide ions getting into your hologram before you have finished processing. ==Developer considerations== Because of the way this bleach operates, particular consideration has also got to be given the developer system used first. It is not satisfactory to have any “physical development “ which encourages silver bromide to be dissolved in the developer. We need to have as much virgin AgBr as possible to create our final diffraction and it makes no sense to load up the developer with sulfite ion­ a weak silver halide solvent and similar remarks apply to urea as in the CW developer. The amount of development is also more important than in the case of the rehalogenating bleach system. Since all the developed silver is going to be washed away, if you develop too much for too long then you start to eat into your virgin AgBr in the dark fringes because even unexposed AgBr is developable given enough time. The consequence is that reflection holograms made with red lasers may look a dull green instead bright yellow/green due to increased contraction . This effect has also been shown to cause a peak in the graph of diffraction efficiency vs. developer/exposure level and after the peak the efficiency drops away. Whereas when a rehalogenating bleach is used after the same developer conditions, the diffraction efficiency flattens off. [Joly] ==Importance of De-ionized rinsing water.== After the developer the hologram needs a good rinse under tap water to remove the developer and soluble bromide and iodide ions in it . Even if the developer had no halide ions initially, the development process means that the AgBr and AgI in the emulsion had to be broken up and turned into dark silver and soluble Br- and I-. The tap water rinse then leaves the emulsion with just chloride ions from tap water which are less of a problem to deal with later than soluble bromide or iodide ions. Before the dichromate bath is used you have to have two pre-baths of de-ionized water (DI) to remove all traces of dissolved halide ions. If you don’t do this then some of the developed up silver fails to be removed from the light-struck fringes and deposits itself back in the fringe as silver halide. This causes scatter in the finished hologram and reduces diffraction efficiency because the light struck fringes have failed to be properly cleared of AgBr . Where even experienced holographers commonly go wrong is that after removing the bleached hologram from this reversal bleach bath, they rinse it under the tap instead of first putting the hologram back in de-ionized water for a second time . This is because after leaving the bleach bath the hologram is full of silver ions in solution which can instantly form silver chloride particles with the chloride ions in tap water. So this causes scattering from inside the emulsion which cannot be wiped away even if surface silver chloride can be. After using the bleach bath you may notice a red-brown precipitate or scum in the bath. This is normal and it is actually good to have it in there. It is made up of silver chromate or dichromate which is not very soluble but is far more soluble than are the silver halides. So what this red sludge means is that your bleach bath is saturated with silver chromate in solution and any stray halide ions in solution are effectively precipitated out before they can get inside your emulsion. Even though some precipitated silver chromate may form in your gelatin layer it comes out easily in the DI bath. After this final DI bath you can then rinse the hologram in tap water to eliminate any dichromate ions if you wish, because there will be no soluble silver ions to cause trouble in a final tap water rinse. (Personally I like having a trace of dichromate in the hologram not washed out because it helps to prevent future printout. However dichromate is quite poisonous and who knows what future use your hologram may be put to particularly with young children around). ==Tap water rinsing== Prolonged tap water rinsing can remove some of your AgBr with significant differences depending on time of year and the temperature of your cold water supply. Any AgBr loss causes a shift to a shorter wavelength replay in the case of reflection holograms and of course some loss in diffraction efficiency but sometimes people prefer to simply shift the color from orange-yellow to yellow-green using a hot water rinse. The result can look brighter, also any scatter from AgCl contamination can be removed because AgCl is about ten times more soluble than AgBr. Some idea of the temperature effect can be seen from this graph: [[Image:SilverSolubility.gif]] ==References== [Joly L., Jacobs P. Spectral Response of reflection gratings on Holotest 8E75 HD Proc. Int’l Symp. on Display Holography, ed. Jeong, T.J. Lake Forest College IL. Vol III p115-126 (1989).] [Owen, B.B. and Brinkley, S.R. J.A.C.S. 60, 2237 (1938).] e75fa688214d0f9739dcc8f1b19b689401b54caa 6 292 467 2006-05-28T06:33:06Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 194 235 2006-05-28T06:36:06Z Colin Kaminski 0 wikitext text/x-wiki [[Image:CIEDiagram.jpg]] 5a100b415dd5ba1b49b021495dd5b2dc3db63f0f 6 316 595 2006-05-28T14:46:24Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 325 613 2006-05-28T14:49:26Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 326 615 2006-05-28T14:52:05Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 327 617 2006-05-28T14:56:40Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 353 799 2006-05-28T14:59:30Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 328 619 2006-05-28T15:01:53Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 329 621 2006-05-28T15:18:56Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 330 623 2006-05-28T15:19:21Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 331 625 2006-05-28T15:21:36Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 319 601 2006-05-28T16:17:05Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 322 607 2006-05-28T16:18:44Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 323 609 2006-05-28T16:19:11Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 324 611 2006-05-28T16:19:36Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 332 627 2006-05-28T16:30:21Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 317 597 2006-05-28T16:30:49Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 318 599 2006-05-28T16:31:21Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 320 603 2006-05-28T16:31:47Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 321 605 2006-05-28T16:32:10Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 568 1286 2006-05-28T18:48:47Z Colin Kaminski 0 wikitext text/x-wiki ==A Simplified Analysis of Holography== Assume a photographic plate in the xy plane: Given a reference beam: [[Image:HoloEQ1.gif]] where [[Image:HoloEQ2.gif]] is the amplitude as a complex number retaining the phase information. The reflected object beam is: [[Image:HoloEQ3.gif]] At the plate the fringe amplitude is given by: [[Image:HoloEQ4.gif]] because the square of the magnitude of a complex number is product with its complex conjugate. (Note: [[Image:PhotographyEQ1.gif]] is the amplitude of a photograph. See how we lose the imaginary part of the equation, this is when we lose the phase.) Thus, [[Image:HoloEQ5.gif]] The first and second terms are intensities of the reference and object beams. The third and forth terms are the magnitude and phase of [[Image:HoloEQ6.gif]]. When we reconstruct the hologram, [[Image:HoloEQ7.gif]], with the reference beam [[Image:HoloEQ8.gif]], so that the transmitted light has the complex magnitude [[Image:HoloEQ9.gif]], [[Image:HoloEQ11.gif]] i.e. [[Image:HoloEQ12.gif]] or [[Image:HoloEQ13.gif]] where [[Image:HoloEQ14.gif]] and is the zero order beam (it passes straight through the hologram). [[Image:HoloEQ15.gif]] is the intensity of the reference beam and [[Image:HoloEQ16.gif]] is the virtual image. The third term, [[Image:HoloEQ17.gif]], is the real image. It is important to notice that its amplitude is the complex conjugate of [[Image:HoloEQ18.gif]]. (We have to flip the plate to make the conjugate or real image.) 245c9c8cc96f8269731a513fc2efb3c8af9b1bcf 0 280 407 2006-05-28T19:09:54Z Colin Kaminski 0 /* Lateral Magnification */ wikitext text/x-wiki Back to [[Holography Transmission Equations]] Part One. ==Lateral Magnification== [[Image:LatMagEq.gif]] Lateral Magnification The ratio of the image distance to the object distance in lensed imagery gives the magnification ratio; how big is the image compared to its original size. There are a variety of equations useful for figuring this out, but the simplest to visualize and most like the holographic equation is: [[Image:MagRatioEQ.gif]] When image distance = object distance, magnification ratio = 1:1, the Xerox machine case. In normal picture taking situations, a magnification < 1 or minification takes place; a whole human figure is reduced down to the size of a piece of film or digital chip, with object distance being much greater than image distance. (The denominator in the equation is bigger than the numerator.) A projector has a short object distance compared to its image distance, and the magnification is >1. (Values of numerator and denominator reversed.) Spare me and don’t ask about what happens when an object is at infinity today. This equation refers to the object’s dimensions in the two planes parallel to the holoplate; the longitudinal, or z dimension magnification is an evil equation and is coming next. It relates the original object wavefront curvature, Robj to it’s current position, Rimg. But it can also apply to what happens when the replay wavelength is different than the exposing one. And our little friend m pops up and although not pertinent to the art of H1 masters it is useful for cases when there are multiple image orders, like in a Gabor hologram and its close relative, the zone plate. So if we put our properly exposed and developed laser transmission hologram back in the plateholder where it was made once again like in the examples above, we can calculate: [[Image:MagLatEqEx1.gif]] Image is the same size as the object, since we haven’t moved anything. In the previous section, the image distance was calculated when the reference beam was moved in closer. (Scenario refresher: reference beam in at 45 degrees from infinity or collimated, object plane 100 mm from plate.) Plugging in these object distances in response to moving in the reference beam closer, we get magnifications of these new object distances over 100 mm, since the ratio of wavelengths is unity and so is m. *R ill = 10 m, *R out = 99 mm; *mag = .99 *R ill = 1 m, *R out = 90.9 mm; *mag = .909 *R ill = 100 mm, *R out = 50 mm; *mag = .5 If the object were a 10 by 10 grid of squares 10 mm (1 cm) on a side, the when the reference was at 10 m, the grids would shrink to 9.9 mm on a side; at 1 m, about 9.1 mm squares; and with that very close reference, they drop down to 5 mm mini-squares. Couldn’t there be magnification just like in the lens examples above? There was none possible in the previous hologram because the reference beam during recording was collimated, parallel and coming from infinity, and there is no longer R ill to plug in and let the equation “grow” in replay. Sharp-eyed readers might realize that there is no R ill in the Magnification Equation. But it’s necessary to find R img for the latter, and so the example will include solving for image distance based on reference replay position, then to be plugged into the magnification equation. The parameters for this hologram will be Robj, the point on the object of interest, positioned 10 cm behind the holographic plate; and a Rref of one meter, a distance easily attainable in a sandbox or other small tabletop isolation system, for the reader to verify themselves. It could also be the basis for a Science Fair Project, something on the order of “Experimental Verification of Predicted Object Magnification in Transmission Holograms.” Or just looking at any transmission hologram by moving it back and forth in an expanding illuminating beam will also bring a sense of relevance to these mathematical meanderings. 1/R out = (lambda ill/lambda exp)(1/R obj - 1/R ref) + 1/R ill = (633 nm/633 nm) X (1/100 mm - 1/1000 mm) + 1/1000 mm = 1 X (.01 - .001) + .001 = .01, R out = 100 mm As usual this is the replay configuration that duplicates the recording, so the object distance in the hologram is the same as in real life, and it’s safe to say that magnification is = 1. Halving the reference distance: 1/R out = (lambda ill/lambda exp)(1/R obj - 1/R ref) + 1/R ill = (633 nm/633 nm) X (1/100 mm - 1/1000mm) + 1/500 mm = 1 X (.01 - .001) + .002 = .011, R out = 90 mm compared to R obj of 100 mm yields a magnification ratio of 90/100 = .9 or 90%. This didn’t yield an object magnification of 50%! This equation works exponentially, not linearly. To see where the reference beam needs to come from for a magnification of 50%, (50 mm object distance, or R out) we need to solve for R ill: 1/R out = (lambda ill/lambda exp)(1/R obj - 1/R ref) + 1/R ill = 1/50 = (633 nm/633 nm) X (1/100 mm - 1/1000 mm) + ? = .02 = 1 X .01 - .001 + ? 1/R ill = .011, R ill = 90.9 mm Going in the other direction, doubling the R ill distance, 1/R out = (lambda ill/lambda exp)(1/R obj - 1/R ref) + 1/R ill = (633 nm/633 nm) X (1/100 mm - 1/1000 mm) + 1/2000 mm = 1 X (.01 - .001) + .0005 = .0095, R out = 105.2631 mm, rounded to 105, for a 5% increase in image size. The largest possible virtual image magnification would be when the R ill is brought all the way to infinity, so 1/R ill drops out, and the object distance is 1/.009, or 111.111… An exercise for the reader would be to think of how to tweak the holographic set up (reference, object distance, and replay distance) for the maximum possible magnification, kind of like a holographic magnifying glass! Another tricky transformation that this equation implies is the change in object size when the wavelength is changed. This was Gabor’s impetus for developing holography; to shoot the hologram with short wavelengths, like electron waves or X-rays, and then replay it in the optical domain for an extreme magnification, namely on the order of the ratio of the wavelengths. Replaying a hologram shot with 6 nm X-Rays with a 589 nm sodium vapor light (this is pre-laser era!) would yield approximately a 100X magnification! Reading the early papers of Gabor and Rogers they did attempt to experimentally verify this by exposing holograms with the blue line of a mercury vapor lamp and replaying it with its green line! Theoretically satisfying, the big practical stumbling block was being able to supply a point source of the really short lambdas! ==Longitudinal Magnification== [[Image:LongMagEq.gif]] ==Vertical Focus== [[Image:VertFocusEq.gif]] ==Off Axis Lateral Magnification== [[Image:LatMagOffEq.gif]] 8a1c53ac6853a0ae9fac0303639bcc2dc6c5fc58 0 188 223 2006-06-03T21:49:16Z Colin Kaminski 0 /* Notes */ wikitext text/x-wiki From Bastian_S: Dielectric mirrors can be cleaned with acetone and appropriate cleaning tissue, for example this one [http://www.whatman.com/products/?pageID=7.29.142 Whatman 105 Lens Cleaning Tissue] if its just a bit dust you can lay the lens paper on the mirror, put 2-3 drops acetone on the lens paper and pull it away over the surface. It should be dry when the lens paper is completely pulled away. If there is more dirt or fingerprints its the best to fold the paper several times and grip it on one edge where its folded with hemostats. Add some acetone and wipe the mirror ONCE. If you need to wipe again you might fold it again and use a new edge or take a new paper. ====Tips==== *Fingerprints might attack the coating of dielectric mirrors if they stay on it for days/weeks so it might be the best to clean them right after accidently touching them. ====Notes==== *A word of warning here on dielectric mirrors. They typically use fluorides of light elements such as magnesium. These have very low but still significant water solubility, getting a film of water on them can be quite bad so that a say 135nm layer carefully coated to reflect say green could suddenly have patches only say 100nm or so because some of it has got washed away in water so it then it reflects blue instead of green. Evaporating acetone very fast in a cold damp room can produce significant water condensation. A warm hair drier should stop this from happening, I don't have a perfect answer, I am just pointing out something to be aware of. - Jeff 22aa19f528eba1e8b8e5d05c5bd4096116708608 0 516 1182 2006-06-04T00:36:09Z Colin Kaminski 0 Typo wikitext text/x-wiki Stop baths are used in holography in the same way they're used in photography, to cease the action of the developing agent. There are several chemicals used from from running tap water, DI water to acetic acid purchased at the chemist or even vinegar purchased at the grocery store. From [1] "The use of a stop bath in ordinary photography is common, but when processing holograms certain points should be kept in mind as regards the type of hologram to the be processed. Amplitude holograms and certain types of phase holograms are also normallly fixed before bleaching. It is important to avoid contamination resulting from the use of different processing solutions, which is why careful washing between active baths is necessary. It is also important to maintain a constant temperature of all processing solutions, including all washing baths. If a develoer contains sodium carbonate (like in D-19) which when mixed with the acetic acid stop bath can cause liberation of carbon dioxide, it will result in the emulsion being perforated with a multitude of tiny bubbles." ==Photographic stop bath== ==Tap water== ==DI water bath== ==Vinegar== ==References== 1 - Silver-Halide Recording Materials - H.L. Bjelkhagen ISBN 3-540-56576-0 12756e57eef09743f092f1f3eaab3ecdb4a09c55 0 479 1108 2006-06-04T01:46:47Z Colin Kaminski 0 wikitext text/x-wiki This is a stub *A great description of DPSS ring lasers can be found in [http://www.holographyforum.org/files/holopdfs/DPSSThesis.pdf Christoph Boling's Thesis]. e97f48dfe4784e3bb475906b946eb7ab87e3e681 0 282 411 2006-06-04T05:01:29Z Colin Kaminski 0 /* How a Laser Works */ wikitext text/x-wiki ==How a Laser Works== Mirrored from Lawerence Livermore Labs [[Image:HowLaser1.gif]] ===Background=== The word "laser" stands for "light amplification by stimulated emission of radiation." Lasers are possible because of the way light interacts with electrons. Electrons exist at specific energy levels or states characteristic of that particular atom or molecule. The energy levels can be imagined as rings or orbits around a nucleus. Electrons in outer rings are at higher energy levels than those in inner rings. Electrons can be bumped up to higher energy levels by the injection of energy-for example, by a flash of light. When an electron drops from an outer to an inner level, "excess" energy is given off as light. The wavelength or color of the emitted light is precisely related to the amount of energy released. Depending on the particular lasing material being used, specific wavelengths of light are absorbed (to energize or excite the electrons) and specific wavelengths are emitted (when the electrons fall back to their initial level). The ruby laser was the first laser invented in 1960. Ruby is an aluminum oxide crystal in which some of the aluminum atoms have been replaced with chromium atoms. Chromium gives ruby its characteristic red color and is responsible for the lasing behavior of the crystal. Chromium atoms absorb green and blue light and emit or reflect only red light. For a ruby laser, a crystal of ruby is formed into a cylinder. A fully reflecting mirror is placed on one end and a partially reflecting mirror on the other. A high-intensity lamp is spiraled around the ruby cylinder to provide a flash of white light that triggers the laser action. The green and blue wavelengths in the flash excite electrons in the chromium atoms to a higher energy level. Upon returning to their normal state, the electrons emit their characteristic ruby-red light. The mirrors reflect some of this light back and forth inside the ruby crystal, stimulating other excited chromium atoms to produce more red light, until the light pulse builds up to high power and drains the energy stored in the crystal. The laser flash that escapes through the partially reflecting mirror lasts for only about 300 millionths of a second-but very intense. Early lasers could produce peak powers of some ten thousand watts. Modern lasers can produce pulses that are billions of times more powerful. Another characteristic of laser light is that it is coherent. That is, the emitted light waves are in phase with one another and are so nearly parallel that they can travel for long distances without spreading. (In contrast, incoherent light from a light bulb diffuses in all directions.) Coherence means that laser light can be focused with great precision. Many different materials can be used as lasers. Some, like the ruby laser, emit short pulses of laser light. Others, like helium-neon gas lasers or liquid dye lasers emit a continuous beam of light. Our ICF lasers, like the ruby laser, are solid-state, pulsed lasers. ===How the First Ruby Laser Works=== [[Image:HowLaser2.gif]] In contrast to an ordinary light source, a laser produces a narrow beam of very bright light. Laser light is "coherent," which means that all of a laser's light rays have the same wavelength and are in sync. [[Image:HowLaser3.gif]] 1. High-voltage electricity causes the quartz flash tube to emit an intense burst of light, exciting some of the atoms in the ruby crystal to higher energy levels. [[Image:HowLaser4.gif]] 2. At a specific energy level, some atoms emit particles of light called photons. At first the photons are emitted in all directions. Photons from one atom stimulate emission of photons from other atoms and the light intensity is rapidly amplified. [[Image:HowLaser5.gif]] 3. Mirrors at each end reflect the photons back and forth, continuing this process of stimulated emission and amplification. [[Image:HowLaser6.gif]] 4. The photons leave through the partially silvered mirror at one end. This is laser light. There are many types of lasers, including solid-state, gas, semiconductor, or liquid. The ruby laser is a solid-state laser. Solid-state lasers provide the highest output power of all laser types. The National Ignition Facility laser will also be a solid-state laser, but will use a special glass (rather than crystals of ruby) to amplify the initial laser pulses to very high energy levels. The NIF laser will be the most powerful laser in the world. 1377da2c3122bb3819bb9a7e4dd44613c070ff78 6 333 647 2006-06-04T05:01:59Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 334 649 2006-06-04T05:02:37Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 335 651 2006-06-04T05:03:09Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 336 653 2006-06-04T05:03:42Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 337 655 2006-06-04T05:04:16Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 338 657 2006-06-04T05:04:47Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 363 841 2006-06-05T01:43:42Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 200 247 2006-06-05T05:27:12Z Colin Kaminski 0 /* Cr4+:YAG Passive Q-Switch */ wikitext text/x-wiki ==Cr4+:YAG Passive Q-Switch== *Formula: Cr4+:Y3Al5O12 *Crystal Structure: Cubic Garnet *Density: 4.56 g/cm3 *Hardness: 8.5 (Mohs) *Damage Threshold: > 500 MW/cm2 *Refractive Index: 1.82 @ 1064 nm *Recovery Time 8.5 µs *Repetition Rate > 30 Hz *Orientation <111> cubic *Absorption of Ground State Level 5.7x10-18 cm2 *Absorption of Exited State Level 8.0x10-19 cm2 Available in initial transmissions of T=40% to T=99% and thicknesses up to 5mm. Maximum transmission is at a fluence of around .6 J/cm^2. 240806bdbfb247ad72b836731a0790ca2faeaa5d 0 403 957 2006-06-06T04:39:42Z Colin Kaminski 0 /* KTP - KTiOPO4 */ wikitext text/x-wiki ==KTP - KTiOPO4== '''Parameters''' *Phase Match Type II *Non-Linear Coeffecient 3.18 x10^-12 m/V at 1064nm to 532nm *Refractive Index 1.74 *Absorption .010 cm^-1 *Transparent Range 350nm to 4000nm *Required Power Density 200MW/cm^2 *Damage Threshold 500MW/cm2 *Phase Matching Angle 24.3 deg *Walk-off Angle .26 Deg *Melting Point 1150 deg C *Lifetime at 80 Deg C and 150MW/cm^2 20 x 10^7 pulses '''Tolerance Parameters (FWHW)''' *Angular 25 mr-cm *Thermal 25 Deg C-cm *Spectral .56 nm-cm 4ccd52cfd1b296bf3955175ab0185696d22a71e7 0 408 966 2006-06-06T05:14:00Z Colin Kaminski 0 wikitext text/x-wiki ==LBO== 577d3295490630caace6d6451dd0b4d98a527036 0 402 955 2006-06-06T05:15:56Z Colin Kaminski 0 /* KD*P KD2PO4 */ wikitext text/x-wiki ==KD*P KD2PO4== '''Properties''' *Phase Match Type II *Non-Linear Coefficient .37 10-12 m/V *Refractive Index 1.49 *Damage Threshold .5 GW/cm^2 *Absorption .005 cm^-1 *Phase Matching Angle 53.7 Deg. *Walk Off Angle 1.45 deg '''Tolerance Parameters ''' *Angular 2.2 mr-cm *Thermal 6.7 deg C-cm *Spectral .66 nm-cm '''Notes''' KD*P is very fragile and is quite hygroscopic. It is supplied in an index matched fluid filled cell to protect the crystal. It is available in very large sizes and is less expensive than KTP. 40711bfc645644d6528e1fbebac32332dd676279 0 444 1038 2006-06-07T04:30:22Z Colin Kaminski 0 /* Room Temperature Transitions */ wikitext text/x-wiki ==YAG Physical and Chemical Properties== *Formula: Y3AI5O12 *Molecular Weight: 596.7 *Crystal Structure: Cubic *Moh Hardness: 8 - 8.5 *Melting Point: 1950°C (3540°F) *Density: 4.55 g / cm-3 *Refractive Index of YAG at 25C and 1.0 (µm)= 1.8197 ==Properties of Nd:YAG at 25°C (at 1.0% Nd)== *Formula: Y2.97Nd0.03AI5O12 *Weight % Nd: 0.725 *Nd Atoms / cm3: 1.38 x 1020 *Wavelength: 1.064 mm *Transition: 4F3/2 — 4I11/2 *Fluorescent Lifetime: 230 µsec *Thermal Conductivity: 0.14 W cm-1 K-1 *Specific Heat: 0.59 Jg-1 K-1 *Thermal Expansion: 6.9 x 10-6°C-1 *dn / dt: 7.3 x 10-6°C-1 *Young’s Modulus: 3.17 x 104 Kg / mm-2 *Poisson Ratio: 0.25 *Thermal Shock Resistance: 790 Wm-1 ==Room Temperature Transitions== *1.052um 46% *1.062um 92% *1.064um 100% *1.065um 50% *1.074um 65% *1.078um 34% *1.105um 9% *1.112um 49% *1.116um 46% *1.123um 40% *1.319um 34% The precentage shown are relative to 1.064nm. ==Main Absorbtion Peaks== *590nm *750nm to 770nm *790nm to 820nm cae49e0a91786842846bfd29f48b564556bbaed6 1 534 1218 2006-06-07T17:06:10Z John Pecora 0 wikitext text/x-wiki I cannot find exact numbers right now and you may have the information at your finger tips but for the yag lasers it is important to include the Near infrared (1.06 microns) wavelength in your reflectivity numbers for cavity materials. The IR pulsed lasers we used always had a gold (polished or plated not sure) cavity interior. It is after the population inversion and subsiquently the lasing the that beam is frequency doubled into the visible wavelength range. John ------------------------- Actually you don't want any reflection at 1064nm as it tends to depopulate the upper energy levels by stimulated emission in directions that are not in line with the mirrors. -Colin ----------------------- Got it. That makes sense. 18b9923bc0859d67bec980c26fed8e3d8cad85e2 0 483 1116 2006-06-07T20:13:38Z Colin Kaminski 0 /* Physical Properties */ wikitext text/x-wiki '''Ruby''' - Chromium doped aluminum oxide (Cr:Al2O3) ====Physical Properties==== *Specific Gravity 3.9 to 4.1 *Hardness 9 *Refractive Index 1.76-1.77 *Fluorescent Lifetime 3.0ms at 300K *Spectral Linewidth 11cm^-1,5.3A *Major Pump Bands 404nm and 554nm *Doping Level .05% by wt. '''TECHNICAL DATA PROPERTIES OF SYNTHETIC SAPPHIRE & RUBY ''' *Chemical Formula: AL 2 0 3 (monocrytalline/hexagonal) *Density: 0.143 lb/in 3 (3.97 gm/cm 3 ) *Specific Gravity: 3.97 *Tensile Strength: 60,000 psi (2600 kg/cm 2 ) min @ 25° *Compressive Strength: 350,000 psi (21,000 kg/cm 2 ) *Modulus of Rupture: 67,000-95,000 psi (4000-7000kg/cm 2 ) *Modulus of Rigidity: 25 x 10 6 psi (19,000 kg/mm 2 ) *Young's Modulus: 51 x 10 4 psi *Hardness: 9 (MOHS) /1800?2200 (KNOOP) / 2500-3000 (VICKERS) *Poisson's Ratio: 0.28 ? 0.33 *Coefficient of Friction: 0.14 (Dry Friction on Steel) *Porosity: 0 % '''THERMAL''' *Melting Point: 3725 0 F (2053 0 C) *Specific Heat: 0.18 cal/g 0 C *Thermal Conductivity: 0.09 cal/sec?cm 0 C *Maximum Operating Temperature: 3632 0 F (2000 0 C) *Coefficient of Thermal Expansion: 4.8?5.3x10 -6 cm/cm 0 C '''ELECTRICAL''' *Electrical Resistivity: 10 16 ohm?cm (@25 0 C) *Dielectric Strength: 480,000 volt/cm (@60 Hz) *Dielectric Constant: 8.5 ? 10.5 (300 KHz ? 1 GHz) *Dielectric Loss Tangent: < 0.0001 [http://www.roditi.com/Laser/Ruby.html Ruby Specs] de510e1c5d9cea22179d5fc362009765a4139764 6 315 591 2006-06-08T06:15:41Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 375 877 2006-06-10T23:02:12Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 569 1288 2006-06-10T23:06:36Z Colin Kaminski 0 /* The Eye */ wikitext text/x-wiki ==The Eye== from LBL [[Image:TheEye.gif]] A diagram of the human eye. The eye is the area of greatest concern with respect to laser safety.The various parts of the eye are described below, along with descriptions of how laser radiation can harm them. ===Cornea=== The cornea is a transparent living membrane that covers the eye. It is very thin and composed of epithelial cells over a supporting matrix. The cornea has no blood supply; thus, its cells have no defense system and are easily damaged, both thermally and mechanically. If corneal injury is minor, then regrowth of epithelium can occur within a day or so without any permanent abnormality. If more extensive injury occurs, corneal scarring may ensue, with loss of the capacity of the cornea to conduct clear images. Damage to the outer cornea ranges from uncomfortable to painful, but will usually heal in one to two days. Damage to the cornea and the conjunctiva tissue surrounding the eye usually occurs at greater power levels than damage to the retina; therefore, these issues only become a concern for those wavelengths that do not penetrate to the retina (UV and IR radiation). Since amplification by the lens is not involved, injuries can also be caused by diffuse and noncoherent light. ===Lens=== The lens focuses light to form images on the retina. The lens does not have an active cellular turnover and thus cannot repair itself. Over the course of repeated minor injury, or even one major injury, the lens may become progressively more opaque. This condition is known as cataract formation. While cataracts are a common side affect of aging, they are accelerated by exposure to certain light energies, including lasers. When UV or IR laser light enters the eye, much of the light is absorbed in the lens. Depending on the level of exposure, this may cause immediate thermal burns or the development of cataracts over a period of years. ===Retina=== The retina is made up of a thin layer of light-sensitive cells called rods and cones, so named for their basic appearance. The rods make up the vast majority of the retina (over 95% of the total retinal area) and are sensitive to both movement and light and dark. They are more sensitive to light than are the cones, but they cannot see color. The cones make up less than 5% of the total retinal area, but that area is the critical central part of the retina, called the fovea centralis, where we see both color and fine detail. The retina is an actual extension of the human brain. Retinal cells detect only what we call "visible light." Laser light in the visible and near-infrared (IR) region (400–1,400 nm) that enters the eye is focused on the retina, creating a hazardous concentration of laser energy out of a "minor" laser source. One mW of visible laser radiation entering the eye deposits 100 W/cm2 at the retina. b9a5ad7681877eca7f3ff3f03f2f4ae03282a117 0 411 972 2006-06-10T23:16:12Z Colin Kaminski 0 wikitext text/x-wiki ===AHD Guidlines for LASER Alignment=== From LBL The following are requirements and suggestions for the laser alignment section of a laser AHD at LBNL (note that the alignment procedures are only one part of the laser AHD). ===Laser Alignment Guidelines to Help Prevent Accidents=== *No unauthorized personnel will be in the room or area. *Laser protective eyewear must be worn. *All laser users must attend the LBNL laser safety class, EHS0280. *The individual who moves or places an optical component on an optical table is responsible for identifying and terminating every stray beam coming from that component. *To reduce accidental reflections, watches and reflective jewelry should be taken off before any alignment. *Beam blocks must be secured. *When the beam is directed out of the horizontal plane, it must be clearly marked. *A solid stray beam shield must be securely mounted above the area to prevent accidental exposure to the laser beam. *All laser users must receive an orientation to the laser use area by an authorized laser user of that area. *Laser users must have had their baseline eye examination prior to performing any alignment procedures. *The lowest possible/practical power will be used during alignments. *When possible, a course alignment should be performed with a HeNe alignment laser. *Have beam paths at a safe height, below eye level when standing or sitting, not at a level that tempts one to bend down and look at the beam. If necessary, place a platform around the optical table to raise one’s height. ===Alignment=== The techniques for laser alignment listed below will be used to help prevent accidents during alignment of the lasers covered by this AHD. ====Initial Considerations==== Access to the room/area is limited to authorized personnel only. Persons conducting the alignment have been authorized by the PI and are listed in this AHD. A NOTICE sign must be posted at entrances when temporary laser control areas are used or when unusual conditions exist that warrant additional hazard information be available to personnel wishing to enter the area. If the laser is a Class IIIb or IV open-beam system, make sure exterior warning signs/indicators are functioning. Use beam blocking barrier or laser curtain to contain beam - Use "Notice" and "Danger" signs per ANSI standards. ====Preparation==== Consider having someone present to help with the alignment. Remove watches, rings, dangling badges, necklaces, reflective jewelry, etc. before any alignment begins. The use non-reflective tools should be considered. Remove all unnecessary equipment, tools, combustible material (if fire is a possibility) to minimize the possibility of stray reflections and non-beam accidents. Skin protection should be worn on the face, hands and arms when aligning UV systems. ====Equipment preparation==== Identify equipment and materials necessary to perform alignment. Have all equipment and materials needed before beginning the alignment. This system requires the following items: tools, targets, beam stops/blocks, power meter/detector, beam profiling system, curtain, signage, caution tape, personal protective equipment (PPE): alignment eyewear, face shields for scattered UV. Pay attention to housekeeping; make sure the immediate work area/benchtop/optical table is free from opportunistic specular reflectors not need for alignment (e.g., glass bottles, razor blades, forceps, screw drivers, optical posts, photographic paper, plastic, dye cells, etc.) ====Area preparation==== Cover windows or viewing ports within the controlled area. Prepare the beam delivery system: remove beam tubes or other parts of the protective housing as necessary, including extended sections that may be covered by beam tubes or bellows; check all optics (mirrors, lenses, filters, polarizers, expanders, etc.) and optomechanical components (base plates, post holders and fasteners, mirror mounts, etc.) ensuring they are currently aligned (for changes/ additions to an existing alignment) and securely mounted. Isolate and demarcate the area to avoid distractions and minimize the hazard to others. If the high-power laser is embedded in other equipment, establish temporary laser controlled area. ====Eyewear==== Appropriate laser protective eyewear MUST be worn by all persons within the Nominal Hazard Zone (NHZ) whenever there is an open Class 3B or Class 4 beam. The NHZ is considered to be the entire room or lab in which the laser is located unless otherwise specified in the AHD. Violation of this policy is cause for a STOP WORK action. ANYONE witnessing a violation of this policy has the right and the obligation to initiate a STOP WORK action and report it to the LSO and division management. You must have the correct eyewear for your wavelength(s) and power. The LSO has authorized reduced optical density eyewear to allow the beam spot to be seen. Measures shall be taken and documented to ensure that no stray hazardous specular reflections are present before the lower OD eyewear is worn. A return to the Maximum OD eyewear as listed in the laser table will be made when the alignment is complete. The eyewear is labeled as alignment eyewear and is stored in a different location than the standard laser eyewear for this operation. ====Beam viewing==== No direct (intrabeam) viewing by eye is allowed unless specifically evaluated and approved by the LSO. Intrabeam viewing is to be avoided by using cameras or fluorescent devices. When using viewing aids to visualize the beam, reach into the beam path slowly and deliberately with the card slightly angled so you can see the diffuse reflection. Adjust the optic so that the beam strikes the card just in front of the surface of the component. Invisible beams are viewed with IR/UV cards, business cards or card stock, craft paper, viewers, 3x5 cards, thermal fax paper, Polaroid film or similar technique. Operators are aware that specular reflections off some of these devices is possible, and that they may smoke or burn. ====Beam control==== Label all areas where the beam leaves the horizontal plane. If the beam path changes elevation (+Z), be aware of the increased potential for vertical reflections. Terminate all stray or unused beams. Confine the beam to the optical table or benchtop. Be aware of the potential for errant reflections (stray beams) from components such as polarizers and dielectric mirrors. Check for stray beams at each step and again after completing all alignment steps. As you progress down the optical path, place beam blocks behind optics to be adjusted to stop errant (stray) beams. Close the shutter or insert the beam block during adjustments; resecure optics making sure components are properly located/adjusted. Make sure that the beam shutter is closed or a beam block is in front of the end window. Make sure beam block is securely mounted. If the beam path to be aligned is located in different rooms, locate a beam block in the beam path between the rooms, and align one room, then the other. If line of sight with personnel in other rooms is blocked, use two-way, real-time communications. Be patient at each step. Restore the system to normal operational mode (pay attention to the protective housing, interlock switches, and shutters) and verify normal operation. ====Light power reduction==== Perform the "rough" or coarse" alignment with the beam blocked. Reduce the beam power through the use of ND filters, beam splitters and dumps, or reducing power at the power supply. Avoid the use of high-power settings during alignment as much as is practical. If the alignment has been performed at lower power or with a low-power collinear beam but final steps will be performed at operational power levels, be sure and change to the appropriate eyewear for the high-power beam. Pulsed lasers are aligned by firing single pulses when practical. For pulsed lasers, use single pulses and/or reduce pump power. For Q-switched lasers, turn off the Q-switch and use in the low-power, CW mode For CW lasers with adjustable power, adjust the power to a minimum stable level. Co-axial low power lasers should be used when practical for alignment of the primary beam. Enclose the beam as much as practical, close the shutter as much as practical during course adjustments, secure optics/optics mounts to the table as much as practical, secure beam stops to the table or optics mounts. If the primary laser is optically pumped by another laser and alignment of the pump beam is necessary, block the primary beam to limit potential multi-wavelength exposure/eyewear concerns, align the pump beam, and then replace beam enclosure in the pump-to-laser beam path. cb3b16c6343c8990426314df631c40993ba123f1 0 488 1126 2006-06-10T23:45:22Z Colin Kaminski 0 wikitext text/x-wiki ==Safe Electrical Procedures== From LBL. '''Positively ensure the correct circuit is identified before lockout and tagout:''' Almost every week, some electrician or technician is hurt in the United States because the breaker he/she locked out was the wrong one. This type of accident is so easily preventable, yet it is far too common. Before you lock out a circuit breaker or power disconnect switch, check that you are locking out the correct breaker — the one that controls the equipment on which you will be working. Breaker off, the equipment stops. Breaker on, the equipment runs. Then, and only then, lock it out! '''Whenever possible de-energize the equipment before testing.''' Conduct tests with the electrical equipment deenergized, or, if there is no other way to perform the test, with reduced hazard. '''The employee in charge must conduct a briefing before all energized electrical work:''' Before starting any diagnostics & test energized electrical work having a Hazard Class greater than 1A or 1B, the supervisor or his/her designee, must complete a Job Planning Checklist (Appendix C) and conduct a job briefing with the employee(s) performing the work. '''Identify hazards and anticipate problems:''' Think through what might go wrong and the consequences of that action. Do not hesitate to discuss any situation or question with your supervisor and coworkers. '''Resist “hurry-up” pressure:''' Program pressures should not cause you to bypass thoughtful consideration and planned procedures. '''Don’t hesitate to use the Stop Work Policy:''' LBNL has a stop work policy (PUB-3000, Chapter 1.5) Do not hesitate to use it if you see a fellow worker performing unsafe acts. '''Always consider electrical equipment energized unless positively proven otherwise:''' When working on electrical equipment, treat the equipment as live until it is tested, locked, tagged, shorted, and/or grounded, as appropriate. '''Use suitably rated electrical devices only as intended:''' Electrical devices shall be fully rated for the system to be tested, and must not be modified beyond the intent of their design. '''Remove or cover all jewelry before performing energized electrical work:''' This includes rings, watches, or metal pendants and chains that could inadvertently fall into the work. Metal-framed glasses must be restrained when working around electrical equipment. '''Know how to shut down equipment in an emergency:''' Know the location, and operation of, emergency disconnects for all sources of power to equipment before beginning energized work. '''Know LBNL emergency procedures:''' All persons working in areas of high hazard (with high-voltage power supplies, capacitor banks, etc.) must be trained in emergency response procedures, which should include cardiopulmonary resuscitation (CPR) certification. '''Design for safety:''' Consider safety to be an integral part of the design process. Protective devices, warning signs, and administrative procedures are supplements to good design—not a substitute for it. Engineering controls are always preferable to administrative controls. Completed designs should include provisions for safe maintenance. '''Reset circuit breakers only after the trip problem has been corrected:''' When a circuit breaker or other over current device trips, it is usually due to an overload or fault condition on the line. Repeated attempts to re-energize the breaker under these conditions may cause the breaker to explode. Do not attempt to reset a circuit breaker unless the problem has first been identified and corrected or isolated. ''Maintain the protection of covers, barriers and shielding:''' When you remove a panel or cover for access (a barrier), replace it with a temporary barrier to restore at least some of your protection. This could be a transparent Lexan sheet, a rubber sheet or blanket, etc., place over the portions of the equipment under test to which you do not need access. '''Never drill into a wall or floor slab without Facilities' approval.''' See Admin 053 Facilities Penetration Policy. When drilling into a wall or floor, wear suitable PPE for the working conditions (dirt, slurry, debris) in case of an unknown electrical hazard. At a minimum, this will include safety glasses, hard hats, all leather shoes, and fully rated gloves. '''Never modify or penetrate premises wiring conduit or enclosed wireways:''' Only qualified and authorized Facilities Department personnel are allowed to work on premises wiring, conduits or enclosed wiring. 1fd10a08506bee1906c5c7ee1fb5d42a471f893d 0 445 1040 2006-06-11T07:33:57Z Colin Kaminski 0 wikitext text/x-wiki ==ND:YVO4 - Vandate== *Lasing Wavelengths : 914nm, 1064nm, 1342nm *Refractive Indices: @1064nm 1.9573(no) 2.1652(ne) *@808nm 1.9721(no) 2.1858(ne) *@532nm 2.0210(no) 2.2560(ne) *Absorption Coefficient: ~31.4%/cm @808nm *Absorption Length: 0.32mm @808nm *Stimulated Emission Cross-Section: 2.50x10-18 cm2 @1064nm *Fluorescent Lifetime: 90 µs (about 50 µs for 2 atm% Nd doped) @ 808nm *Intrinsic Loss: 0.02/cm @ 1064nm *Gain Bandwith: 0.96nm (257 GHz) @ 1064nm *Polarized Laser Emission: p polarization;parallel to optic axis (c-axis) *Diode Pumped Optical to Optical Efficiency: >60% ===Physical Properties:=== *Crystal Structure: Zircon Tetragonal, space group D4h *Cell Parameters: a=b=7.12Å, c=6.29Å *Mohs Hardness: »5 *Density: 4.22g/cm3 *Hygroscopic Susceptibility no *Thermal Conductivity(W/cm·K): parallel to c: 0.0523; vertical to c: 0.0510 *Thermal Expansion Coefficient: parallel to a: 4.43x10-6; parallel to c: 11.37x10-6 36508e66cbf4ed350f686a4a2d3ca589e63b5f90 0 175 197 2006-06-11T07:45:24Z Colin Kaminski 0 /* Chemical Properties */ wikitext text/x-wiki ==BBO== ===Physical Properties=== *Crystal Structure trigonal, space group R3c *Cell Parameters a = b = 12.532Ä, c = 12.717Ä, Z = 6 *Melting Point 1095 +/-5°C *Transition Temperature 925 +/-5°C *Optical Homogeneity Dn ≈10-6/cm *Hardness 4.5 Mohs *Density 3.85 g/cm3 *Absorption Coefficient < 0.1%/cm (at 1064 nm) *Hygroscopic Susceptibility low *Resistivity > 1011 ohm-cm *Relative Dielectric Constant eT11/e0: 6.7, eT33/e0: 8.1 *Tan d, < 0.001 *Thermal Expansion Coefficients(in the range of 25°C- 900°C) a, 4 x 10-6/K c, 36 x 10-6/K *Thermal Conductivity ^c, 1.2 W/m/K; ||c, 1.6 W/m/K ===Chemical Properties=== *Phase-matchable SHG range 189-1750nm *NLO coefficients d11 = 5.8 x d36(KDP) *d11 = 0.05 x d11, d22< 0.05 x d11 *Electro-Optic Coefficients g11 = 2.7 pm/V, g22, g31< 0.1 g11 *Half-Wave Voltage 48 KV (at 1064 nm) *Damage Threshold 5 GW/cm2 (10 ns) **at 1.064 mm 10 GW/cm2 (1.3 ns)1 GW/cm2 (10 ns); **at 0.532 mm 7 GW/cm2 (250 ps) *Transparency Range 189 - 3500 nm *Refractive Indices **at 1.0642 mm ne = 1.5425, no = 1.6551 **at 0.5321 mm ne = 1.5555, no = 1.6749 **at 0.2660 mm ne = 1.6146, no = 1.7571 *Therm-Optic Coefficients **dno/dT = - 9.3 x 10-6/°C **dne/dT = -16.6 x 10-6/°C c9268d428f1472c38e7f4994d246a877debc9a74 6 350 767 2006-06-12T01:50:17Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 487 1124 2006-06-12T03:56:05Z Ron Michael 0 minor edit, changed temporal to spatial regarding modes wikitext text/x-wiki [[Image:SSY1.jpg]] The SSY-1 laser is available surplus very inexpensively. It has a Plano-Plano resonator with [[Nd:YAG]] as the active medium and a passive Q-Switch. This laser can be modified to make a master oscillator but the alignment of a Plano-Plano cavity is the most sensitive of any cavity configuration making it very difficult to align and keep in alignment. This is taken care of very well in the original design but it makes for a difficult design to modify. ie. increase the cavity length. Replacing the OC (Output Coupler) with a resonant reflector helps with the coherence length but alignment is made simpler by replacing the HR (Highly Reflective Mirror) with one with a large radius. It's output is not polarized and has multiple spatial and longitudinal modes. Since the cost is so low many amateur hologaphers are working at modifying it for holographic use. '''Specs''' *Plano/Plano Resonator *Nd:YAG 4 mm x 50mm *Passive Q-Switch *Diffuse Cavity *Flash Lamp 3mm bore x 35 mm long *Recomended Flash Lamp input 900V at 15J *Output 15 to 50 mj at 1064nm *100us optimal flash lamp pulse [http://www.repairfaq.org/sam/laserscl.htm#sclsy1 Sam's Laser FAQ on the SSY-1] 6c9757e300f13ffe695f9ffe944c7c32f718bce7 0 227 301 2006-06-12T04:51:55Z Colin Kaminski 0 wikitext text/x-wiki An etalon is a optical devise inserted into a laser cavity in order to extend the coherence length. It works by selecting a single frequency of the cavity and only allowing it to propegate. The other modes present are extiguished. :'''''Etalon''' redirects here. '''Etalon''' is also the French word for [[stallion]].'' In optics, a '''Fabry-Pérot interferometer''' or '''etalon''' is typically made of a transparent plate with two reflecting surfaces, or two parallel highly-reflecting mirrors. (Technically the former is an etalon and the latter is an interferometer, but the terminology is often used inconsistently.) Its transmission spectrum as a function of wavelength exhibits peaks of large transmission corresponding to resonances of the etalon. It is named after Charles Fabry and Alfred Pérot. 'Etalon' is from the French ''étalon'', meaning 'measuring gauge' or 'standard' [http://www.allwords.com/word-etalon.html]. Etalons are widely used in telecommunications, lasers and spectroscopy for controlling and measuring the wavelength of light. Recent advances in fabrication technique allow the creation of very precise tunable Fabry-Pérot interferometers. Fabry-Pérot interferometers also form the most common type of optical cavity used in laser construction. Telecommunications networks employing wavelength division multiplexing have add-drop multiplexers with banks of miniature tuned fused silica or diamond etalons. These are small iridescent cubes about 2&nbsp;mm on a side, mounted in small high-precision racks. The materials are chosen to maintain stable mirror-to-mirror distances, and to keep stable frequencies even when the temperature varies. Diamond is preferred because it has greater heat conduction and still has a low coefficient of expansion. In 2005, some telecommunications equipment companies began using solid etalons that are themselves optical fibers. This eliminates most mounting, alignment and cooling difficulties. == Theory == [[Image:Etalon-1.png|frame|right|A Fabry-Pérot etalon. Light enters the etalon and undergoes multiple internal reflections.]] The varying transmission function of an etalon is caused by interference between the multiple reflections of light between the two reflecting surfaces. Constructive interference occurs if the transmitted beams are in phase, and this corresponds to a high-transmission peak of the etalon. If the transmitted beams are out-of-phase, destructive interference occurs and this corresponds to a transmission minimum. Whether the multiply-reflected beams are in-phase or not, depends on the wavelength (&lambda;) of the light, the angle the light travels through the etalon (&theta;), the thickness of the etalon (''l'') and the refractive index of the material between the reflecting surfaces (''n''). The phase difference between each succeeding reflection is given by &delta;: :<math>\delta = \left( \frac{2 \pi}{\lambda} \right) 2 n l \cos\theta. </math> [[Image:Etalon-2.png|frame|right|The transmission of an etalon as a function of wavelength. A high-finesse etalon (red line) shows sharper peaks and lower transmission minima than a low-finesse etalon (blue).]] If both surfaces have a reflection coefficient ''R'', the transmission function of the etalon is given by: :<math>T_e = \frac{(1-R)^2}{1+R^2-2R\cos(\delta)}</math> Maximum transmission (''T''_e = 1) occurs when the optical path-length difference (2''nl'' cos ''&theta;'') between each transmitted beam is an integer multiple of the wavelength. In the absence of absorption, the reflectivity of the etalon ''R''_e is the complement of the transmission, such that ''T''_e + ''R''_e = 1. The maximum reflectivity is given by: :<math>R_{max} = \frac {4R}{(1+R)^2} </math> and this occurs when the path-length difference is equal to half an odd multiple of the wavelength. [[Image:etalon-finesse-vs-reflectivity-2.png|thumb|400px|right|Finesse as a function of reflectivity. Very high finesse factors require highly reflective mirrors.]] The wavelength separation between adjacent transmission peaks is called the free spectral range (FSR) of the etalon, &Delta;&lambda;, and is given by: :<math>\Delta\lambda = \frac{ \lambda_0^2}{2nl \cos\theta } </math> where &lambda;₀ is the central wavelength of the nearest transmission peak. The FSR is related to the full-width half-maximum, &delta;&lambda;, of any one transmission band by a quantity known as the finesse: :<math> \mathcal{F} = \frac{\Delta\lambda}{\delta\lambda}=\frac{\pi}{2 \arcsin(1/\sqrt F)}</math>, where <math> F\equiv \frac{4R}{{(1-R)^2}}</math> is the ''coefficient of finesse''. This is commonly approximated (for ''R'' > 0.5) by :<math> \mathcal{F} \approx \frac{\pi \sqrt{F}}{2}=\frac{\pi R^{1/2} }{(1-R)} </math> Etalons with high finesse show sharper transmission peaks with lower minimum transmission coefficients. A Fabry-Pérot interferometer differs from a Fabry-Pérot etalon in the fact that the distance ''l'' between the plates can be tuned in order to change the wavelengths at which transmission peaks occur. Due to the angle dependence of the transmission, the peaks can also be shifted by rotating the etalon with respect to the beam. === Detailed analysis === [[Image:Fabry Perot Diagram1.png|320px|right]] Two beams are shown in the diagram at the right, one of which (<math>T_0</math>) is transmitted through the etalon, and the other of which (<math>T_1</math>) is reflected twice before being transmitted. At each reflection, the amplitude is reduced by <math>\sqrt{R}</math> and the phase is shifted by <math>\pi</math>, while at each transmission through an interface the amplitude is reduced by <math>\sqrt{T}</math>. Assuming no absorption, we have by conservation of energy <math>T+R=1</math>. Define ''n'' as the index of refraction inside the etalon, and <math>n_0</math> as the index of refraction outside the etalon. Using phasors to represent the amplitude of the radiation, let's suppose that the amplitude at point <math>a</math> is unity. The amplitude at point <math>b</math> will then be :<math>T_0=T\,e^{ikl/\cos\theta}</math> where <math>k=2\pi/\lambda</math> is the wave number inside the etalon. At point <math>c</math> the amplitude will be :<math>TR\,e^{2\pi i + 3ikl/\cos\theta}</math> The total amplitude of both beams will be the sum of the amplitudes of the two beams measured along a line perpendicular to the direction of the beam. We therefore add the amplitude at point ''b'' to an amplitude <math>T_1</math> equal in magnitude to the amplitude at point ''c'', but which has been retarded in phase by an amount <math>k_0l_0</math> where <math>k_0=2\pi n_0/\lambda</math> is the wave number outside of the etalon. Thus: :<math>T_1=RT\,e^{2\pi i+3ikl/\cos\theta-ik_0l_0}</math> where <math>l_0</math> is seen to be: :<math>l_0=2l\tan(\theta)\sin(\theta_0)\,</math> Neglecting the <math>2\pi</math> phase change due to the two reflections, we have for the phase difference between the two beams :<math>\delta=2kl/\cos(\theta)-2k_0l_0\,</math> The relationship between <math>\theta</math> and <math>\theta_0</math> is given by [[Snell's law]]: :<math>n\sin(\theta)=n_0\sin(\theta_0)\,</math> So that the phase difference may be written :<math>\delta=2nkl\,\cos(\theta)\,</math> To within a constant multiplicative phase factor, the amplitude of the m-th transmitted beam can be written as :<math>T_m=TR^m e^{im\delta}\,</math> The total transmitted beam is the sum of all individual beams :<math>A_T=\sum_{m=0}^\infty T_m=T\sum_{m=0}^\infty R^m\,e^{im\delta}</math> The series is a [[geometric series]] whose sum can be expressed analytically. The amplitude can be rewritten as :<math>A_T=\frac{T}{1-Re^{i\delta}}</math> The intensity of the beam will be just <math>A_TA_T^*</math> and, since the incident beam was assumed to have an intensity of unity, this will also give the transmission function: :<math>T_e=A_TA_T^*=\frac{T^2}{1+R^2-2R\cos(\delta)}</math> ===Another expression for the transmission function === [[Image:LASCO C1a.png|thumb|200px|A picture of the solar corona taken with the LASCO C1 coronagraph which employed a tunable Fabry-Pérot interferometer to recover scans of the solar corona at a number of wavelengths near the FeXIV green line at 5308 Å. The picture is a color coded image of the doppler shift of the line, which may be associated with the coronal plasma velocity towards or away from the satellite camera.]] Another useful expression for the transmission function may be derived as follows: The sum representation of the amplitude <math>A_T</math>&nbsp; may be used directly to express the transmission function: :<math>T_e=T^2\sum_{m=0}^\infty \sum_{n=0}^\infty R^{m+n}\,e^{i(m-n)\delta}</math> Defining <math>l=m-n</math>, rearranging terms, and using the [[geometric series]] formula on ''R'' yields :<math>T_e=\frac{T^2}{1-R^2}\sum_{l=-\infty}^\infty R^{|l|}\,e^{il\delta}</math> The terms of the sum are seen to be the [[characteristic function]] of the [[Lorentz distribution]] which allows the sum to be written: :<math>T_e=\frac{T^2}{1-R^2}\sum_{l=-\infty}^\infty \int_{-\infty}^\infty L(\delta-\delta';\gamma)\,e^{il\delta'}\,d\delta' </math> where <math>L(x,\gamma)</math> is the Lorentz distribution: :<math>L(x;\gamma) \equiv \frac{\gamma}{\pi (x^2-\gamma^2)}</math> and <math>\gamma\equiv\ln(1/R)</math>. The order of integration and summation may be interchanged which yields a sum over the exponential term alone. This sum is seen to be a [[Dirac comb]] <math>D_T(x)</math> and so the transmission function is seen to be the [[convolution]] of a Lorentzian function and a Dirac comb: :<math>T_e=\frac{2\pi\,T^2}{1-R^2}\,\,L(\delta;\gamma)*D_{2\pi}(\delta)</math> ==References== *{{cite book | first = G. | last = Hernandez | year = 1986 | title = Fabry-Pérot Interferometers | publisher = Cambridge University Press | location = Cambridge | id = ISBN 0521322383 }} *[http://www.micronoptics.com/telecom_ffp.htm Micron Optics' optical fiber etalons] 4544c1f7d6183b2e8b0538adcad39310be38b68f 0 443 1036 2006-06-16T01:37:17Z Colin Kaminski 0 wikitext text/x-wiki Nd:Glass is a large family of materials. The properties of one of them is listed so far. ===Q-246=== Silicate Nd:Glass *Wavelength 1063nm *Cross Section 2.9x10^-20cm^2 *Flourescent Lifetime 330 u sec *Linewidth FWHM 27.7nm *Loss .002%-cm^-1 *Index of Refraction 1.572 *Index of Refraction @ 1063nm 1.561 *Nonlinear Index 1.4 N2 (10^-14 esu) *dn/dt 2.9 (10^-6/deg C) *Thermal Expansion 96 x 10 ^-7/ deg C *Thermal Conductivity .82 W/m*K *Specific Heat .80 J/g*K *Density 3.206 g/cc *Hardness (Knoop) 558 *Young's Modulus 7150 Kg/mm^2 *Poission's Ratio .24 *Damage Threshold >25 J/cm^2 (1ns) aa5f2359a1f7d27ac3160ccd400788f593adb517 6 312 583 2006-06-18T16:15:16Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 255 357 2006-06-18T16:21:27Z Colin Kaminski 0 wikitext text/x-wiki [[Image:HBjelkhagen.jpg]] Dr Hans I. Bjelkhagen, professor of Interferential Imaging Sciences, with North East Institute for Higher Education, Wrexham, at the Centre for Modern Optics located in OpTIC Technium in North Wales, UK. He received his PhD degree in 1978 from the Royal Institute of Technology in Stockholm, Sweden. There he developed methods for recording interferometric holograms and performed holographic nondestructive testing for the Swedish car and airplane industry, e.g., VOLVO and SAAB. In addition to industrial applications of holography, Dr Bjelkhagen specialised in medical and dental holographic recordings. Dr Bjelkhagen has developed a holographic recording system for dental casts. The equipment: HOLODENT SYSTEM was produced and marketed by Dentatus International AB in Sweden. He has also invented and patented a special method to detect caries lesions (tooth decay) at an early stage based on laser fluorescence. Currently, a quantitative clinical system based on that patent is being developed and marketed by INSPEKTOR Research Systems bv in Amsterdam, the Netherlands. In 1983, he joined CERN in Geneva, Switzerland, where he was involved in development of bubble chamber holography. A year later he participated in an international team working on neutrino physics experiments recording holograms in the 15-foot bubble chamber at Fermilab in Batavia, IL, USA. Between 1985-1991 he was at Northwestern University, Evanston, IL, working on medical endoscopic applications of holography. He developed methods of recording in-vivo holograms at the tip of a special fibre-optic endoscope. Dr Bjelkhagen has been involved in the development of a large autostereoscopic computer display system when working for American Propylaea Corporation and Intrepid World Communications in Michigan. The project was carried out between Propylaea and US Army Tank Command, Warren, MI, through a CRDA (A Cooperative Research and Development Agreement). The work resulted in a prototype based on a 30" by 50" projection HOE and an array of single-lens video projectors and run by Silicon Graphics ONYX computers. During the last ten years, Dr Bjelkhagen has been most recognized for his work in colour holography, holographic recording materials and Lippmann photography. Dr Bjelkhagen has been able to demonstrate that high-quality full-colour holograms recorded in "white" laser light (combined RGB light from three laser wavelengths) could be stored in a single-layer ultra-high-resolution silver halide emulsion. In December 1997 Dr Bjelkhagen was invited by Professor Nicholas Phillips to join him at the newly established Centre for Modern Optics at De Montfort University, Leicester, in England. There he continued his research on 3D imaging, colour holography, colour HOEs, holographic recording materials, and Lippmann photography. Currently, a new optical variable device (OVD) based on the one-hundred-year-old Lippmann photographic colour recording technique is being developed. The application is in the field of optical document security. Individually recorded OVDs, similar to reflection holograms, can be applied to documents, such as, passports, ID-cards, driver’s licenses, etc. At the Centre for Modern Optics he has been involved in projects supported by companies, such as, SAMSUNG and SHARP. In addition to his scientific 3D coherent imaging Dr Bjelkhagen is a well-known holographer who has recorded many holograms for 3D display purposes. From his early years in holography he has been involved in large-format, high-quality display holography both pulsed and cw laser holography. He has recorded many unique art objects, such as, e.g., the Swedish Coronation Crown of Erik XIV (from 1561) in 1974 and the Chinese Flying Horse from Kansu (from 100 A.D.) at an exhibition in Stockholm in 1976. Dr Bjelkhagen has been working with several famous artists, for example, Carl Fredrik Reuterswärd, creating holograms exhibited in many art museums and art galleries around the world. Dr Bjelkhagen has specialized in pulsed display holograms, in particular, holographic portraits. He has recorded holograms of many people the most famous one being President Ronald Reagan, a portrait recorded May 24, 1991. This is the first and, so far, the only holographic portrait recorded of an American president. One copy of the holographic portrait is in The National Portrait Gallery of the Smithsonian Institution in Washington DC. When Dr Bjelkhagen was working in the USA in the 80s and 90s, he started two holographic companies together with two of his colleagues in Chicago. One company was HOLICON Corporation, a company specialised in large-format pulsed holography and portraiture. Among the interesting projects can be mentioned a promotional project for Bristol-Myers Squibb Company: "The Gallery of the Pathogenesis of Atherosclerosis" using hologram of microscopes through which arteries could be studied. After the campaign was over, the holograms were donated by Bristol-Myers Squibb to museums in the USA, for example, the Museum of Science and Industry in Chicago, where the holograms are still on display. HOLICON was also financially responsible and provided equipment for recording the 1991 holographic portrait of President Ronald Reagan which took place at Brooks Institute of Photography in Santa Barbara in California. The other company, Holographic Industries Inc., operated several Lightwave Hologram Galleries, marketing holograms and other holography-related products and located in US cities such as, e.g., Chicago, Detroit, and San Francisco. Dr Bjelkhagen has published over 100 papers in refereed journals and conference proceedings and holds 9 international patents. However, his most important academic contribution is the Springer book on Silver-Halide Recording Materials for Holography and Their Processing. That book considered to be the standard textbook on the subject is now used in many of the universities teaching holography as well as in most worldwide companies producing display holograms. Bjelkhagen is a member of the Optical Society of America (OSA) and a Topical Editor of the society's journal Applied Optics. He is a fellow the International Society for Optical Engineering (SPIE) and the co-chairman of SPIE's Holography Technical Group. He is an Accredited Senior Imaging Scientist and Fellow of The Royal Photographic Society (RPS). Bjelkhagen received the RPS SAXBY AWARD in 2001 for his work in holography. *2004 - present Professor, Interferential Imaging Sciences North East Institute of Higher Education, Wrexham, and Centre for Modern Optics at OpTIC Technium, St. Asaph, Wales *2001 -2004 Professor, Interferential Imaging Sciences, De Montfort University, Leicester, England. *1997 - 2001 Senior Research Fellow, Modern Optics De Montfort University, Leicester, England. *1996 - 1997, Visiting Research Scientist, Lake Forest College, Lake Forest, Illinois, USA. *1994 - 1995, Vice President - Research & Development, American Propylaea Corp., Birmingham, Michigan, USA. *1992 - 1994, Visiting Professor, University of Münster, Germany. *1985 – 1992, Associate Professor, Biomedical Engineering, Northwestern University, Evanston, Illinois, USA. *1985, 1991, Associate Professor, Applied Photonics, Louis Pasteur (6 months each University, Strasbourg, France. *1984 1985, Visiting Research Associate, Fermi National Accelerator Lab, Batavia, Illinois, USA. *1983 1984, Visiting Research Associate, CERN (European Organization for Nuclear Research), Geneva, Switzerland. *1978 1983, Associate Research Professor, Production Engineering, Royal Institute of Technology, Stockholm, Sweden. *1969 1978, Research Assistant, Production Engineering, Royal Institute of Technology, Stockholm, Sweden. Swedish citizen, UK resident, US Green Card Holder, Date of Birth: March 9, 1945, Stockholm, Sweden. 7a944325261a7a59821e9f838a2f8cbfea485bf2 6 309 577 2006-06-19T01:17:56Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 311 581 2006-06-19T01:18:38Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 310 579 2006-06-19T01:20:31Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 308 575 2006-06-19T01:21:27Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 421 992 2006-06-19T01:43:15Z Colin Kaminski 0 /* Optically Variable Device for Security Documents */ wikitext text/x-wiki '''Optically Variable Device for Security Documents''' *Professor Hans I Bjelkhagen *Centre for Modern Optics *OpTIC Technium *St Asaph Business Park *ST ASAPH LL17 0JD, UK *hansholo at aol dot com ===INNOVATION=== The innovation is based on an old colour photographic technique, interferential photography or Lippmann photography, which was invented in 1891 by Gabriel Lippmann.[1] He was awarded the Nobel Physics Prize for his invention in 1908. Lippmann photography was the first technique, which could record colour photographs directly in the camera. However, the technique had several limitations, e.g., a special type of isochromatic film was needed, the image could not be copied, the image switched between a negative and a positive colour image depending on viewing direction. These limitations are now real advantages for a photographic document security device. A Lippmann photograph can be applied as a new type of Optically Variable Device (OVD) to be used on individually issued security documents, such as, e.g., identification cards, passports, credit cards, driving licences, and other documents where a high degree of security is needed. A Lippmann photograph is very similar to the embossed holograms currently used in this field; however, a unique recording of each document can be made to achieve a degree of security higher than that with mass-produced holograms. The recording of Lippmann photographs requires a special type of photosensitive recording material in contact with a reflecting layer. Modern panchromatic photopolymer materials or ultra-high-resolution silver halide emulsions can be used and, after being recorded and processed, laminated to security documents. A special type of recording equipment is required. Lippmann photographs are virtually impossible to copy and, certainly, cannot be copied by conventional photography or colour copying machines. ===Brief description of the recording technique=== A Lippmann photograph can be recorded on a photopolymer material in the following way. The photosensitive layer has to be rather thin, in the order of a few micrometers only. The light-sensitive layer must be coated on a flexible transparent base and a special type of reflecting foil has to be laminated on top of to the photosensitive polymer layer in perfect contact with it. Experimental photopolymer materials have been manufactured by DuPont, e.g., the HRF-700X071-3 film. This film was used to prove the concept of recording Lippmann photographs in modern photopolymer materials.[2] The polymer film laminated to the reflecting foil must be exposed in a special camera. After being exposed to the image-forming information in the camera, the reflecting foil is detached from the photopolymer film and the photopolymer layer is exposed to strong white light or UV light for developing. The image brightness is increased by heat treatment of the recorded film. The whole processing technique of the photopolymer film is a completely dry process, which makes it suitable for manufacturing a recording/processing machine intended for Lippmann security labels: Lippmann OVDs. After being processed, the transparent photopolymer label is laminated to its corresponding security document. The polymer film contains no dyes or any fading chemicals, which means that the archival stability is expected to be very high. The photograph is simply a piece of plastic material with the information recorded in it as an optical phase structure (refractive index variations within the photopolymer layer). In Fig. 1, a sample US passport is shown having a Lippmann OVD attached in the upper right corner. Figure 2a shows a close-up of the Lippmann OVD in colour, when observed perpendicular to the passport page. In Fig. 2b, the Lippmann OVD appears as a negative when viewed at an angle. [[Image:HBfig1.jpg]] Fig. 1. Passport with a Lippmann OVD. [[Image:HBfig2a.jpg]] Fig. 2a. Lippmann OVD in colour. [[Image:HBfib2b.jpg]] Fig 2b. Lippmann OVD as a negative. Note that these digital photographs cannot show the quality of the real Lippmann photograph with its extremely high image resolution. [[Image:HBfig3.jpg]] Fig 3. A passport with a Lippmann OVD attached in the upper left corner. Light from a diffuser above the passport makes it easy to inspect the Lippmann OVD on the passport. ===Advantages of the Lippmann OVD=== As already mentioned holograms are common in the field of document security, where mass-produced embossed holograms are attached to many types of security documents and most commonly recognised are the holograms on VISA and MasterCard credit cards. In almost every case where holograms are used, exactly the same hologram image is attached to a large quantity of security documents of the same type, e.g., the embossed dove hologram on the VISA cards. Since holograms are difficult to manufacture and lasers are required for the actual recording of a hologram, the use of holograms has been a valuable security device over many years. Nowadays, however, it is possible to copy holograms and there are examples of illegally copied security holograms reported. Nevertheless, a hologram is a very valuable OVD for mass-produced security instruments such as bank notes, cheques, vehicle stickers, product labels, etc. Lippmann photography offers a new type of optical security device that is unique and can be individually produced for each security document issued. Some of the advantages of a Lippmann OVD as a security device are: *Automatic recording and processing equipment for Lippmann OVDs can be manufactured to be used by security document producers and institutions issuing security documents. *The recording is rather simple to perform, no specially equipped laboratory is required. *The access to the recording photosensitive film, the special photopolymer material, can be strictly controlled by the manufacturer of the film. Only approved producers of security documents and institutions issuing such documents can order the material from the film manufacturer (e.g. like bank note paper). *The Lippmann OVD has a very high archival stability. *The Lippmann OVD is Bragg sensitive, which means it changes its colour depending on the angle of illumination and observation. It also switches between a positive and negative image. These features are extremely important as the effects are easily recognised when inspecting the Lippmann OVD. (Fig. 2 a and b) *The Lippmann OVD cannot be copied by conventional colour photography nor can it be copied using colour copy machines or colour scanners. *Since the resolution of the Lippmann OVD is extremely high, a reduced image of the security document can be laminated to the document, occupying only a limited area of it. In this case, magnifying techniques may be necessary to be able to read all the recorded information in the high-resolution Lippmann photograph. One example of a Lippmann OVD used for document security and counterfeit-resistant purpose is on a passport. The Lippmann OVD can be recorded of the passport page including specific information about the individual, the signature, and the conventional colour photograph of each issued passport. Then, a reduced-size Lippmann image is laminated to the page at an appropriate place. The colour shift of the Lippmann OVD indicates that it is a genuine Lippmann photograph and not a conventional photograph. In addition, all the information recorded in this OVD can be compared with the corresponding information in the document itself. It is a very difficult process to go through if someone wants to tamper with Lippmann-protected documents. The most important advantage is that there is really no point in trying to copy a Lippmann OVD since it is unique to a particular passport and of no use applied to a different passport. The authenticity of a Lippmann OVD is easy to verify simply by looking at it. However, it is also possible to make automatic inspection equipment that can check the iridescence of the image or compare the information recorded on the document itself with the corresponding information stored in the Lippmann OVD. The innovation (the application of Lippmann photography to security documents) is protected by a US patent and pending European patents.[3] The Lippmann OVD was first described in a paper published in Optical Engineering.[4] DuPont has expressed an interest in developing and manufacturing the special photopolymer film needed. Design and development of the recording and processing equipment are required. There is also more work needed to improve the quality of the recording material for Lippmann OVDs. There is a worldwide interest in increasing the security of documents in general. In England, OVDs have been introduced to protect banknotes. In this case a kinegram is used, which is similar to embossed holograms. Personalised documents, e.g., the UK passport, also carries an OVD. However, identical holograms are used on all passports. Credit cards, although they are also personalised documents, all carry identical holograms. Recently, Germany introduced a new type of passport which contains a monochrome, individually-made 2D hologram, overlaminated to the passport page. There is no doubt about the fact that personalised documents need to be more difficult to fake, which means, adding personalised security features to them. The worldwide market for document security is large and rapidly growing. The holographic security industry including the worldwide OVD market size in 2001 was $1.09 billion. There are many personalised documents which would benefit from a higher degree of security, for example, driving licences, traveling documents (Shengen Visa), corporate ID cards (air pilot's ID cards, people working in nuclear power stations), and military personnel, police officers, custom inspectors, etc., are all potential candidates for more secure ID documents. The approach as regards Lippmann OVDs as security devices is to introduce a complete recording/processing system which is used in house for the manufacturing of the labels. Currently, mass-produced embossed holograms and other types of OVDs (e.g. the kinegram) are produced by different holographic companies and then delivered to the issuers of security documents to be attached/laminated to various security documents. Since the Lippmann OVD is unique to a particular document, there is no need to produce them in advance. Therefore special recording/processing machines have to be made which can be sold or leased to companies or authorities issuing security documents. The machine is similar to a photocopier. The security document issuer records the Lippmann OVD at the same time the document is prepared. In this way the issuer has full control of the process and the security around it. ===REFERENCES=== # G. Lippmann, "La photographie des couleurs," C. R. Hebd. Séances Acad. Sci. 112, 274-275 (1891) # H. I. Bjelkhagen, "Lippmann photographs recorded in DuPont color photopolymer material," Proc. SPIE 3011, 358-366 (1997) # H. I. Bjelkhagen, "Secure photographic method and apparatus," US patent No. 5,972,546, Oct 26, 1999 # H. I. Bjelkhagen, "A new optical security device based on one-hundred-year-old photographic technique," Opt. Eng. 38, 55-61 (1999) 05bdb31738824daee6011edf37dfba801bb8b07e 0 430 1010 2006-06-19T03:13:41Z Colin Kaminski 0 /* Stainless Steel */ wikitext text/x-wiki Learning to build a pump cavity allows a frugal holographer to utilize many surplus components. The requirements of a pump cavity are: *Concentrate light on the active medium. *Dissipate the heat generated inside the cavity. *Electrically isolate the flash tube. ==Calculating the Ellipse== [[Image:PumpCavity1.jpg]] The lower the ratio of height to width of the ellipse the more efficient the pumping will be. Since the rod and the flash lamp are placed at their respective foci this meens that the rod and the lamp must be as close together as feasible. Aditional space must be allowed for mounting and machining considerations. ==Material Selection== ===Copper=== '''Advantages''' *Great Thermal Conductivity *Easy to plate '''Disadvantages''' *Poor Reflectivity Requires Plating *Does not take a good polish requiring polishing after plating ===Aluminum=== '''Advantages''' *Great thermal conductivity *Very good reflectivity for Ruby systems *Takes a very good polish '''Disadvantages''' *If not coated the surface can tarnish *Not the best reflectivity for pumping Nd:YAG *Inexpensive and commonly available ===Stainless Steel=== '''Advantages''' *Very hard *Polishes well *Plates easily '''Disadvantages''' *Low thermal conductivity *Difficult to machine *Very chemical resistant *Must be plated ==Polishing the Reflective Surface== Polishing the cavity is like doing any other polishing. You start at the finest grit that will remove the deepest scratch. Once the surface has a uniform scratch pattern you move to a finner grit. Making a fitting for your drill is the fastest way to polish a tube. *Coarse (less than 400 grit) *400 grit *600 grit *800 grit *Red Polish *White Polish ==Plating== ===Nickel=== ===Aluminum=== ===Silver=== ===Gold=== ==Making the Ellipse== ==Designing and Fabricating End Plates== ===Polishing End Plates=== ==Electrical Considerations== ==Water Cooling== a4be1aa2f7036a8f20f74f9c4fb9328f86c5afe4 0 414 978 2006-06-22T01:16:41Z Ron Michael 0 update wikitext text/x-wiki Tools Needed: * Nice feature to have is quick change tool post. * Indexable cutter set; 5 piece holder set with different orientations of the indexable cutter bits. * Drill chuck/drills for tail piece. Smaller end mills also can be used. * 1/16" cutoff blade and holder. * Boring bars and holders. If you get a quick change tool post, these usually come with 5 different holders. Make an optic adapter. Place some round stock in the 3 jaw lathe chuck and tighten. Face the end of the part by using an indexable cutter across the face. Run a cutter along the outside diameter cutting 20 to 40 thousands off aluminum per pass. Just before the OD is reached with 10 thousands make a slow good clean pass to provide a better finish. Chuck up in the tail piece a drill and bore into the face of the part. Use progressively larger drills or end mills to get to the ID you want. If a tool is not close enough, then use a Boring bar to shave off the last little bit of ID. Use a cutoff blade tool slowly and give yourself time by pulling in and out the blade to make sure it is not wandering off at an angle or snags and breaks. Place the part in a drill press with an X Y table and drill a set screw hole or use a Mill for the same job. Hand tap the hole and place a nylon tip set screw in for the optic adapter. Square holes will require the mill and small end mills inorder to fabricate. 5cb4fea4f745f094cd77b1e5fd9a054d2f26bda1 0 436 1022 2006-06-22T04:39:59Z Colin Kaminski 0 wikitext text/x-wiki Tools needed: * vise held down with tnut etc hardware. A good vise is KURT with better than 6" opening preferred. * set of different height parallels 1/8 inch thick for small parts and 1/4 inch for the larger ones. * Dial Calipers * end mills: center cutting 2 or 4 flute. * collet system to hold end mills. Spring collets like the ER40 on larger mills are nice. * DRO (digital readout) is a nice feature to have but not necessary. * drill chuck and drills * rubber mallet Basics: Make sure your mill is trammed [http://www.jjjtrain.com/vms/mill_movments_vert_hd.html] Place part in vise on top of parallels and tighten vise. Use rubber mallet to pound down the part and tighten vise more parallels should not move if seated well. Making a rectangle object Best to square up the sides first. Place part in vise cut one side, flip part over and cut other side. Lay part flat using the two fresh cut sides in the vise and use the side of the cutter to cut 3rd side. Flip part over and cut 4th side with the side of the cutter. Now sides are square and the part can be placed at correct height to cut the faces of the part. Flip part over and cut last face. ===Links=== [http://en.wikipedia.org/wiki/Milling_machine Wikipedia] af5b4f9ae22955f5f944c199595b39cbffcc38be 6 379 893 2006-06-22T14:44:13Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 380 895 2006-06-22T14:52:00Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 381 897 2006-06-22T14:52:35Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 382 899 2006-06-22T14:53:08Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 383 901 2006-06-22T14:53:36Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 384 903 2006-06-22T15:08:23Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 385 905 2006-06-22T15:09:52Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 386 907 2006-06-22T15:11:06Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 347 723 2006-06-24T00:25:14Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 356 807 2006-06-24T00:26:50Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 387 913 2006-06-24T00:27:27Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 304 557 2006-06-24T00:27:52Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 389 917 2006-06-24T00:28:25Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 269 385 2006-06-27T05:46:48Z Colin Kaminski 0 wikitext text/x-wiki This site is run by [[Colin Kaminski]] as a web based Holography information source as part of [http://www.holographyforum.org www.holographyforum.org]. It is really not very expensive to run but if you wish to donate to the cause you can through PayPal. The cost of maintaining the Wiki part of this site is $25 per year above the $20 per month to run the Holography Forum. Click this link to donate $20 to the Holography Forum. [https://www.paypal.com/xclick/business=colinsk@pacbell.net&item_name=Holography+Forum+Donation&amount=20.00&no_shipping=1&return=www.holographyforum.org/thankyou.html&currency_code=USD Donate with PayPal] The best donation you can give the HoloWiki is your time. Any time you spend writing and editing will help every holographer to have a better understanding of our craft. 552d67ababccd9466841fa17ec7d0e5a4804276b 0 459 1068 2006-06-27T19:01:55Z Michael Harrison 0 wikitext text/x-wiki This section could use some work on laser-lit transmission holograms and refinement on the instructions for rainbows. ==General tips== * Use a digital camera. This will allow you to experiment to your hearts content without worrying about burning film. * Always turn your flash off, it will never help when photographing holograms. * Use a good steady tripod. Minor shake can cause ugly blurring in what could otherwise be a good photo. * If your camera has them, experiment with the manual exposure, metering, aperture and ASA controls. If your camera records all these settings in the exif data you won't need to write down what settings go with what picture. If anything is missing, make sure you take good notes so that you'll know what settings give you the best results. * Take your pictures in a dark room (excepting the single light used to illuminate your hologram) so that you won't see reflections of the room in the surface of your hologram. * If you can't make your room sufficiently dark and find that reflections of you or your camera are visible in the hologram glass, do the following. Take a large sheet of black cloth and cut a slit in it big enough to pass the lens of your camera through. Place sheet over your camera with the lens sticking through the slit and wrap a rubber band around the slit edges and lens so that the sheet is held in place. When taking your pictures drape the sheet over your head so that you and the camera can't be seen in the hologram glass. You may need a sheet large enough to cover the legs of your tripod if it's highly reflective. * If your camera has difficulty focusing on the image in the hologram instead of the glass take the hologram and lean it such that it is shimmed away from a flat surface or wall by an inch or so. Take a piece of white card and lie/lean it next to the hologram at the flat surface or wall (it will be an inch or so further away from the camera then the hologram). Now take the digital camera and point it at the white card and hold the button half way down. This locks in the focus and exposure of the white card. Now without releasing the button, move to the hologram and push the button in the rest of the way which will take the photo. By adjusting the distance separation between the card and the hologram (1/4 inch, 1/2 inch, 1 inch etc.) you should be able to get the hologram to be in focus. By adjusting where you point the camera on the card (edge or middle) and by holding down the button you should be able to lock in different degrees of exposure/aperture as locking on to the hologram itself overexposes the photo. * For lighting use a single halogen bulb plugged into a dimmer so that you get a clear single source of light and can control the brightness to get the best image. * Optileds can also be used to provide narrow-band replay light that results in less haze and clearer, deeper hologram reconstruction. ==Rainbow Holograms== To photograph these, if you want the greatest detail, I would recommend the following: * Make sure you have a really good point source of light, so the image is as sharp as possible. As you have a camera and tripod, you can use a long exposure, and the image does not have to be bright. So move your reconstruction light as far away as convenient from the hologram. The image will get dimmer but sharper. I am assuming the hologram is designed to be viewed with a collimated or near-collimated beam. * Now move your camera towards or away from the hologram till the image is a single color. Now you are in the projected 'slit' of the rainbow hologram. * Move the camera up and down till the center of the image is the color you want the image to be. * Move camera towards or away till the entire image is in that color. * Switch off flash; put camera ASA setting to minimum, e.g. 50 * Focus the image. Simple digital cameras don't normally allow manual focusing these days, but try different things till the image looks as sharp as possible. * If you have any control, keep the aperture as wide as possible, i.e. f/2 is better than f/16. This will minimize speckle. * To minimize shake you could put on timer and the camera will shoot a few seconds after you press the button. All would be so much simpler with an old fashioned manual camera, or else a pro digital camera with full control. Good luck. ==Links== 2354bd98dd43215e9669cf8ce917d3b3d4daea73 0 435 1020 2006-07-07T21:59:30Z Michael Harrison 0 wikitext text/x-wiki [[Image:MichaelHDag.jpg]] Born in Houston, TX in 1966 I became enamored with holography in 1984 soon after seeing the first National Geographic with a hologram of an Eagle on the cover. Up to that point I'd never asked for much beyond the typical geek-oriented holiday and birthday gifts such as telescopes, microscopes, circuit kits and the like but that summer I bought the Holography Handbook and soon after asked my parents for a laser. My mother liked to tell the story that after I asked for a laser she called up my father and said "he finally asked for something. He wants a laser." Unlike all her other kids I didn't ask for a car (I was 18 by this time) but asked for something right out of left field as far as they knew. My dad scrouged a .5mW laser out of a telecopier and I set about building a 4'x4' sand table in my bedroom. I made a few transmission holograms over the next year but nothing wonderful. I did end up cracking the foundation though. Fortunately my parents were forgiving. Since diving back into holography in 2003 I've made hundreds of holograms, some not worth keeping but I keep most anyway and have made many more worth keeping, selling, giving away to friends and associates as well as hanging on my walls. I enjoy sharing what I know in person, on the Holography Forum, through the PCG and tutorials on my web site. The full body of my work is available on my web site at [http://holography.dragonseye.com Dragon's Eye Holography] a31af0d54055130efaef6b2f1b52b60d7a75bb74 0 219 285 2006-07-07T22:00:39Z Michael Harrison 0 /* Drilling a hole in a drill press */ wikitext text/x-wiki ==Drilling a hole in a drill press== *Layout the position of a hole with a scribe. *Mark the exact hole position with a punch. *Drill large holes by predrilling a hole matching the diameter of the web of the drill bit. *Choose the correct speed for the size hole and the material being drilled. *When in doubt use slow speeds and strong feeds. *Smaller holes require quicker speeds and lighter feeds. *Back holes in soft materials with another piece of material to prevent "Blowout". ==Seting up a drill press== *There shold be only the smallest amount of play when trying to move the chuck back and forth by hand. *Make sure when drilling through work that the drill bit can not come in contact with the table. *Use a piece of 1/2" drill rod in the chuck with a square to measure the table for squareness. *Setup holes so the minimum amount of quill extention is required for drilling a hole. ==Speeds and Feeds== *Steel *Aluminium *Soft Wood *Hard Wood ==Safety== *Never leave the key in the chuck wihile changing drill bits. *Never wear gloves while holding work in a drill press. *Always try to hold down work by bolting it to the table or by using a vise. *Always usy eye protection when using a drill press. *Unplug or remove the dafety key when chaning drill bits. *Never allow the chip fromed by drilling a hole to grow larger than 1 inch. If the chip starts to become a string relax pressure on the feed until the chip breaks off. 8942021b2424387fca466042bac1ea6493cbe919 0 393 937 2006-07-07T22:29:46Z Michael Harrison 0 Added image that doesn't have the light shining in someone's eyes and information on using a camcorder to evaluate fringe behavior wikitext text/x-wiki ===The Michelson Interferometer=== http://www.dragonseye.com/interferometer.jpg This is one of the most useful tools in a holographer's laboratory. Placed on the holographic table and observed carefully, it can answer many questions - * how long does it take for the table to settle after components are moved? (this could be minutes to hours to a day or more!) * does the table ever completely settle? * what outside factors influence the stability of the set up? (like hearing a car going by and seeing if the fringes move) * what times of day are the most stable? * are the movements due to air movement, vibrations, temperature etc. ? * how long does it take the table to settle after a plate is loaded? and a variety of other useful vibration feedback. If the Michelson is rigidly fixed on an optical rail and allowed to equalize then the interferometer can be used to study properties of the laser such as mode hop behavior, drift and coherence length. ====How It Works==== The Michelson Interferometer uses a beam splitter to split a laser beam into two beams. Each beam takes a different path towards its own mirror which reflects it back into the beamsplitter which now acts to combine the beams so that they overlap. The overlapped beams are fed through a lens and expanded onto a wall or white card. The beams interfere to form fringes which can be seen and studied. The beams in the diagram are slightly offset so that the laser light isn't reflected back into the laser cavity. This reflection back into the laser can cause gas lasers to fluctuate in power and cause fringe movement and even ruin diode lasers. ====Diagnosing Fringe Behavior ==== *Fringes drift slowly back and forth, either continuously or sporadically - This is most likely due to air currents. Create a breeze and see if it affects the drift. *Fringes move slowly and continually in one direction - This is drift and most likely an optic is drooping or the table is sagging in one spot (this is most often seen on sand tables). *Fringes jitter rapidly - This is most likely caused by vibrations coming through the table legs or a fan or other electrical component on the table is vibrating. *Fringes stay stable then jump - This is called a mode hop. It is common when lasers are changing temperature. Allow your laser to warm up before use. If you aren't using a diode laser this can also be caused by air pressure changes. Make sure the AC is turned off and doors in your building aren't being opened and closed while testing with the interferometer or making an exposure. Inserting a plate into the plateholder - the time it takes for the fringes to stop moving is the minimum settling time needed after you load a plate for table movement to stop. [[Equipment#Longitudinal_Modes_and_Coherence_Length|Coherence Length]] - start with both legs of the interferometer set to exactly the same length (to within a millimeter if your coherence length is unknown). When you get all your mirrors aligned properly, you should see fringes. If and when you do, they should be contrasty, not washed out. If not, ask the holography forum for help. After the fringes stabilize, increase the length of one of the legs by a small amount. If fringes remain and are still contrasty your laser is still coherent to the length of the difference in path lengths. Continue to increase the length of the same leg until the fringes are not contrasty or disappear entirely. At this point you have exceeded your coherence length. To find the exact length start to go back from this length to the laser known good length in small increments. ====Tests==== Once the fringes are stable, do a variety of tests. Tap the table slightly and see how long it takes for the fringes to stop moving. Tap the floor with your foot and see how long it takes for the fringes to stop moving. Have someone tap the floor with their foot at different locations remote from the table, i.e. next room, upstairs, downstairs, further away etc. while you are viewing the fringes. Watch the fringes at different times of day - at night when streets are quiet, daytime when streets are busy etc. An excellent way to evaluate your table is to set up a camcorder aimed at the fringes and set a walkie-talkie next to it. Now move around your house/building and walk around, open and close doors, start machinery (if in a home, start your dishwasher etc) and generally cause vibrations while talking into a second walkie-talkie. You can then review the tape and see exactly what, if anything affects your ability to make a hologram in your lab. This tape also serves as a record of table behavior that can be used at a later date to compare current and past behavior. ===References=== Great references for using holograms as measuring tools: Schumann, W. and Dubas, M., Holographic Interferometry, Springer, 1979. Schumann, W., Zürcher, J. P., and Cuche, D., Holography and Deformation Analysis, Springer, 1985. 8d78817779f3b350c9b11dd2d1c90f977058eb2e 1 546 1242 2006-07-12T14:33:24Z John Pecora 0 wikitext text/x-wiki Colin, your amazing and this Wiki is great. I was reading over the HeNe section this statement is contained, "If the mirrors are placed at Brewster's Angle then the laser will have a Polarized output. Some HeNe lasers have mirrors that are external to the glass tube and some have mirrors bonded into the glass tube." I am not sure how the mirrors can be placed at brewsters in an in line cavity. But I didn't want to change is as I surely could be lacking in understanding here. Also, I have taken pictures of my SP Argon Ion and will be uploading them soon. I will let you link them where you think best or tell me and I will do it. I assume in this section would be one good place to link them. Also, with these discussions, would it be advantageous to delete the discussions after they are outdated or leave them? John --------------------------------------- No you are right it should be Brewster's windows with external mirrors. Your understanding is exactly correct. For now leaving the discussions helps people to realize what the pages are for so I have been leaving them. Colin PS Have you seen the MOPA page? It is comming along. I'll announce it when it is further along. --------------------------- Yes I have seen it. Your doing an amazing job. I am grateful for your unending enthusiasm for the WIKI. John ---------------------- Colin, I don't seem to be able to see the photos of the Argon Ion laser I uploaded. I could see them the day I uploaded them but not for the laser week or so. Is it on my end or on the Wiki end? John ----------------------- This is aproblem on my end. I can't seem to find the setting for the Max image size. I think it is set to around 50K. When I have had problems like thi I make the picture files smaller. I looked for a good 40 minutes for the setting but I cna't find it. I'll keep working on it. ---------------------------- If it's easier, you can just make the files smaller so that they are displayed. John --------------------------------- 9c84899608364fe3ebcc303f35129c2ee231fce7 6 307 573 2006-07-12T15:53:10Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 540 1230 2006-07-13T15:08:09Z Michael Harrison 0 wikitext text/x-wiki How does one delete an entry? This article needs to go away. 3a43db2cbf91d2d636a749f4021ab62ce2a49225 1 528 1206 2006-07-13T16:04:25Z John Pecora 0 wikitext text/x-wiki At what point does one become a "professional" holographer? Anyone have any opinions on when someone should be listed in the pro vs amateur category? ------------------------ I think in the Olympics one is no longer an amateur when they have made money practicing that sport. So I am not sure but I assume it would be, once you sell a hologram your are a professional. JohnFP 59f86cb90350bc356487b7ff363b84e7ff8982c7 6 371 865 2006-07-13T16:35:01Z Hans de Jong 0 A temperature controlled diode laser wikitext text/x-wiki A temperature controlled diode laser 87f8a37fae3224989a6ca24576fd5824790059e4 6 372 867 2006-07-13T16:37:54Z Hans de Jong 0 A temperature stabilized laser diode wikitext text/x-wiki A temperature stabilized laser diode a3e9858c28a332e1188c245870b8d6174cecfb9a 6 343 691 2006-07-13T16:55:46Z Hans de Jong 0 A simple constant current source for a laser diode. wikitext text/x-wiki A simple constant current source for a laser diode. 90f9ad444139d094484f511968e082b58ed7cad5 6 376 879 2006-07-13T17:07:05Z Hans de Jong 0 Top view wikitext text/x-wiki Top view 9d597493304aed540ed1f806581a50f570082497 6 377 881 2006-07-13T17:09:43Z Hans de Jong 0 Top View wikitext text/x-wiki Top View e800176ba71bf1fe8e9abff8def5e052dfc9da34 6 344 693 2006-07-13T17:12:02Z Hans de Jong 0 Power Source wikitext text/x-wiki Power Source eccc3205e121f540e66387a9aa3e240cff28df30 6 373 873 2006-07-13T17:26:50Z Hans de Jong 0 How it looks. :) wikitext text/x-wiki How it looks. :) aaec8421cdb668a79950c02d258c6c1e5a32b1c1 0 512 1174 2006-07-16T01:41:33Z Colin Kaminski 0 wikitext text/x-wiki Soldering a Laser Diode is a easy way to kill it! *The diode is very fragile. *Don't bend the pins, subject the diode to shock or static electricity. *Make sure to use a heatsink when soldering and use very thin wire for the connections. *Use very fine wire as the stiffness of the wire can bend a pin and break an internal wire. *Keep the leads from the driver to the diode short. *Shield as much of the wire as possible. 0825253ddfa92d8e9506df5879d951c6f4171aa3 0 166 179 2006-07-17T10:36:07Z Michael Harrison 0 wikitext text/x-wiki The bio below was shamelessly pulled from Andres' home page and could use further editing. I have been involved in holography for quite some time. It started back in 1988 when I was in high school and needed to do some experiments for my school science fair week. At the time, all I had was a small 0.5mW HeNe from Metrologic that my grandfather bought for me after a very intense negation with him :), a limited supply of Agfa Holographic plates and one of the best resources of the time for the amateur holographer, the famous Holography Handbook by Fred Unterseher, Jeannene Hansen and Bob Schlesinger. The setup consisted of a sand box (as described in the handbook) resting on top of 4 inner tubes and 4 cinder blocks, some mirrors, lenses, Kodak D19 developer and a few other chemicals for development and bleaching (can’t remember the names). The process was very frustrating at the beginning. After using almost half the box of holographic plates, no hologram was obtained. You can imagine how wonderful it was when I was able to produce my first hologram. It’s a day I will never forget… I was only able to work with holography for a very limited period at that time and I was not able to do any holography work for 13 years. That all changed in 2003 when I met Michael Harrison. Susan, his wife, works with me and she used to bring Michael’s holograms to the office all the time. It didn’t take long for me to notice that and after talking with her decided to meet him. Well, suffice it to say, I got hooked instantly. Michael’s setup at his house is impressive and he was more that willing to help me get started again. This time though, things were a lot easier. First, I have another holographer that lives 5 minutes from my house, the internet, the holography forum for discussing anything holograhic with profesional and amateur holographers all over the world and last but not least, there is e-bay, the best source for equipment, lasers, optics, books, and anything relating to holography. My current setup is a lot more complex that my first one, it consists of an isolation table top built using a light weight material called Hexcel (a honeycomb material) sandwiched between three layers of steel sitting on top of inner tubes. A pair of 8” parabolic mirrors, spatial filter, magnetic bases to hold components, tons of lenses and mirrors and of course a laser (15mW HeNe). http://www.ghisays.net/default.php 00929dcbc49c1862c22afc4f93b7af016ec5560d 6 359 815 2006-07-18T20:14:52Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 3 581 1312 2006-07-19T13:13:13Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 355 803 2006-07-19T15:56:11Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 454 1058 2006-07-19T22:59:37Z Ron Michael 0 /* Tips */ updated a few more tips. wikitext text/x-wiki The minimum coherence length needed for holography is the twice depth of the scene unless [[Multiple Coherence Volumes]] are used. In order to preserve your coherence length you need to make sure the distance from the laser to the film is with in the coherence length of your laser. This is extremely important with inexpensive HeNe lasers with a coherence length of only a few inches and not so important on lasers that have 50M or so of coherence length like the Coherent C315. In a complicated set up you can end up with 5 or more laser beams. Every one of the beams needs to be traced and measured. There two methods in common use. ===Method 1=== The easiest way is to use a piece of string. Since the distance from the laser to the first beam splitter is the same for all paths we can start our measurements from the first beam spliter. Hold the end of the string against the beam splitter mount at a place that is the same distance as the reflective surface. Then hold the string to the next mirror or optic and keep your finger on that place of the string. Then starting where your finger was on the string continue down it to the next optic or plate and mark this on the string. Continue this until you reach the film plane. Now, mark film plane intersection on the string with a piece of tape (the edge facing the starting end of the sting). This is your path length. Now repeat the same for the second beam path again starting at the beam splitter. Adjust one of the optics to gain or lose distance such that both path lengths are the same. Do this for all paths from the beam splitter. If a second beam splitter is used then each path from that splitter needs to be matched but independenly of the total length from the first beam splitter as stated above the path to the second beam spliter will be the same for each of the split beams. This method may require two people depending on geometry and table size. This is a little confusing, it is important to make sure that when going to the second beamsplitter thet the first path measured not be shifted. It is only the unmeasured path that needs to be changed. I'll think of how to reword it... ====Tips==== *Use a rigid string and not a stretchy one like nylon. Test the string by holding one end the pull it just taught against a wall or table. Then add additional pulling tension. If the string stretches easily and continuously DO NOT USE IT. If it does seem to stretch a little but then a lot of force is needed to stretch it more, it can be used and note the pressure needed to get past the original stretchyness of the string. You will need this pressure when using it on the holographic table. *A piece of fishing thin wire and most fishing lines do not have stretch are are preferable. *'''Make sure to include the distance from the object to the film for object beams!''' * Unless your laser is single longitudinal mode, you want to make sure your path length is even multiples of 2L where L is the length of between resonator mirrors in your laser. So for a HeNe that is 12 inches long you want to make sure the path length is either 24,48,etc multiples of 24 inches. Odd multiples is where the beam intensity will be it's lowest. * In Pulse lasers don't forget it's the distance from the oscillator so you need to know the laser's internal path length as well. * Finally don't forget about polarization. If you use a standard optical table mounted setup with mirrors all the same height as the object then a vertical polarized laser orientation gives a brighter image than a horizontal one. ===Method 2=== Another method it to use a carpenters retractable rule, the metal kind that roll up into a casing (Tape Measure). Most of these rules are designed with a curve such that you can be at the casing end of the rule, pull it out and hold it at just the casing end and the extended end will support its own weight and remain rigid. Thus using this method has two benefits. One, longer lengths can be done by just one person. Second, there is no error of trying to hold the string and mark it with one hand and keep the mark for the next set of optics. *Simply extend the rule from the beam splitter to just past the first optic. *Then hold the rule such that the extended end is at the optic surface then measure to the beam splitter surface. *Write down the length. *Do this for each segment until the film plane. *Add up the lenghts and that will give you a final length from the beam splitter to the emulsion surface. *Then do the same for each beam after the beam splitter. But the disadvantage is as follows. Say that you have a beam splitter then one mirror in each path and then the film. With the string simply find the length from beam splitter, to mirror to film and mark the string. Now with the second path simply hold the end of the string at the beam splitter and the marked end at the film and pull the center of the string out so that it makes a "V" this is where you can place the second transfer mirror. The rigigidity of the tape make this difficult. It may be advantageous to use the string to get approximate optic placements, then use the tape method to be more precise. ====Tips==== *'''Be careful not to scratch the optics!''' *The wider the tape, the longer distance it can remain unsupported. ===Example Diagram=== In the following diagram you can see that each path (green, red and blue) are all equal to one another starting at the first beam splitter. It is important, especially if your coherence length is low, to be precise in your measurements. Measure from the exact plane of the emulsion (in this example the emulsion is on one side of a glass plate), from the reflection side of the beam splitter for both beams and from the center of the depth of the object. [[Image:TransSetUp.JPG]] '''Split Beam Reflection Diagram.''' Note: All of the beams are of one color and from one laser. The different colors are shown to represend different path lengths. '''Red''' Object beam 1. *4.5+4+4.25+3.5+1.25=17.5 '''Green''' Reference beam. *1.5+5+5+6=17.5 '''Blue''' Object beam 2. *4.5+4+4.25+3.5+1.25=17.5 Note: Using this method (using center of object) the coherence length of your laser will very nearly dictate the depth of your object. 340f51f2fae2f1de83a1b18b1e73b884dd2243d5 6 360 817 2006-07-20T01:22:55Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 348 725 2006-07-20T01:24:48Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 357 809 2006-07-20T01:25:11Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 388 915 2006-07-20T01:25:29Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 305 559 2006-07-20T01:25:48Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 390 919 2006-07-20T01:26:04Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 535 1220 2006-07-20T07:18:26Z Colin Kaminski 0 wikitext text/x-wiki I'm inspired by the work being done here. Thank you Colin for putting up such a great wiki system! That said, the main page is a little weak right now. Especially after Technology gets broken out, this page should be a little less than line-items down a page. Perhaps groupings and more utilization of the unused real estate of the page. See my toyings on the [[sandbox]] page for some style examples which control layout (experiements to see how much I could control on a page). -Phil ------ Phil, All of the changes you have made on other pages have made things look better and made it more clear and easier to read. I trust your judgment. Please feel free to edit, move, split or rename pages at will, remember if we get somewhere we don't like we can revert. Colin ---- OK, thanks. I wasn't sure where the line was drawn for major changes/moves. I'll start digging a little deeper. -Phil ---- I will try to keep the '''''Recent changes''''' to a minimum but I was playing with changes to an existing format and wanted to embed images and do it on a linked page. JohnFP ---- What does the bold '''m''' and '''N''' stand for on the Recent changes page? JohnFP ---- '''m''' is a minor edit, meaning you checked the box. '''N''' is a new page or file addition. Don't worry about the amount of recent changes. :-) ---- OK, I put up a new main page. I'm not stuck on it, so rip it apart or whatever, it won't hurt my ego. ;') Keep in mind, that the styles define where (physically on the page) the links and text are. So, moving them into a different order does nothing. You have to tweak pixel offsets if you want BTW- The image was created using my red diode, DPSS green, and DPSS blue lasers... ha! yeah right. It's really from three seperate photos, all done with the same ancient HeNe laser. Each was turned into grayscale and colorized R,G, & B (I tried to eyeball reasonable laser colors). When layered together, the lightbulb became a very convincing white all by its self. I basicly blurred the crap out of the background, foreground, and bulb, removed 'stuck' pixels from my crappy dig camera, and added a slight embelishment from the reflected rays off the lightbulb. But, those highlights on the counter are untouched. -Phil ---- Ah, another important note is: I tried to order the topic for newbies (obviously) to the upper left, and then informational links down the left. Users in unfamiliar web pages tend to start upper left and work down. Hard core technical info goes down the right side (i.e. stuff for people who MAKE holograms). People looking for info browse the left, producers of holograms the right. It helps keep the people hitting the page for the first time in an area that they are likely to be most interested in. And, users who are familiar shouldn't have any problem looking to the right for the links they want. -Phil ---- I like the new page. I made it a little smaller to fit in one screen view for most monitors. I don't know haw to change the link colors on one page only. I know how to set them for the whole wiki. I am afraid the the blue visited link is too dark. ---- Phil that is great and amazing. I like it. John ---- I don't like the darkened image, but I total agree that the links aren't bright enough. Hummm. Overriding that style w/i the wiki is a bit of a problem. I'll ponder and play some more. Another random thought is that the 'main' page could be a static page outside of the wiki, but that might be a bit premature since things are still in major flux. At some point the main page might benefit from the added customization and control of being static. TTYL, and have a good weekend, guys! -Phil ---- I did not delete some of the older revisions of the file, I just renamed them. Play with the brighter ones. If you find one that the writing is not overwhelmed by the light bulb I am cool with having a brighter image. I like how the lasers bounce throough the lightbuld and illuminate spots on the table. ---- I am trying to change the links to a bright green for this page only. I don't quite understand this article: [http://meta.wikimedia.org/wiki/User_styles#CSS_selectors] Can we do it with this? Colin ---- I don't quite understand that page either. Can you include a css style sheet just for the main page? If so, then I think we can just create a style for bodyContent.a {color:green} (Or something like that) -Phil ---- OK, take a look at my personal page for a possible work around: http://www.holographyforum.org/HoloWiki/index.php/User:Phil_Edelbrock -Phil ---- I like that solution. Good Idea! I would prefer the words to be 532nm green. Then we could brighten up the image again. The old image was tough to view on LCD monitors as it was a little overwhelming. Colin ---- I assume you've got photoshop, right? I'll attach the PSD here. I started with a light green color, but Lippman got hard to read with the lighter image. BTW- Lippman Photography seems to be a rather odd topic to throw on the main page. It seems like it should belong to another broader category like under Technology? (edit: oops, I can't upload the file here. I emailed it to you Colin.) -Phil ---- Tweaked home page after chatting w/ Colin. Centered the light bulb (I wish it were straighter). I swapped Recording Tech and Technology, too, so they were more readable. Please email me if you want the photoshop file (phil (at) philedelbrock.com) -Phil ---- I moved the "obtaining Login" information to the footer. I also moved the What is a wiki to the about article. I then changed the page naming so it adds "A Holography Database". I think this will help us target the search engines better. ---- I reduced some wordiness on the bylines to one-liners. I think it looks and reads a bit better, but feel free to edit/revert. -Phil ---- I like the look and feel of the one liners. I would like so text for the google bots to find. Now that the text is in the image there is very little for gogle to search. Do you have any ideas? -Colin ---- Here are the original descriptions I chose them to be searchable. Perhaps we can imbed the text invisably into the main page? Welcome to the [http://www.holographyforum.org Holography Forum's] Holography Wiki. The goal of this wiki is to create a knowledge base for the holographic arts. It is divided into sections as follows: *'''[[Holography for Beginners]].''' A FAQ for beginning holographers. *'''[[Holography Technology]].''' The hardware and setups for making holograms. *'''[[Hologram Recording Materials]].''' *'''[[Holography Theory]].''' The Mathematics of Holography. *'''[[History of Holography]].''' A project to document the people and events before we grow old and forget how exciting this last 60 years has been. *'''[[Holography Safety]].''' Knowledge and practices. *'''[[Biographies of Holographers]].''' The people who have made the magical world of holography posible. *'''[[Holography Links]].''' The World Wide Web for Holography. *'''[[Holography Glossary]].''' A Glossary of holography releated terms. ---- Ok, that still needs lots of work, but I have to run to work. ---- Yeah, they could just be under the image. Google will see them and others won't. (edit: lol, I was thinking under the image literally as a style layer underneith, but a text summary at the bottom of the page works great, too. Probably better since we can see and edit it.) -Phil ---- I revised the footer nav. Colin, if you have the psd file that made the current image handy, center up the light bulb (say 10 pixels to the left, from eyeballing it). That will help make Lippmann a little easier to read and center up the image. This is really great stuff on the wiki. I'm glad to be a part of it, I just wish I had more time/money to help. ;') -Phil ---- I made a new logo for the holography forum link in the footer. It is much sharper. I tried to move the bulb around but I am not skilled enough. I was creating problems on the right edge and then I was loosing some of the laser light bouncing down from the bulb under some of the words. :-( -Colin Feel free to clean up the Hologram Recording Materials section on the main page. I tried to add (& Chemistry) which is in the code but could not get it to show up on the Main Page. So I modified the description underneath. I believe we need this as it is hard to find where chemistry is discussed on the main page. JohnFP Never mind. I found that what I tried to alter in the titles ended up breaking the links, so I just added to the discription of each on the main page to include chemistry. JohnFP --------------------------------------------------------------------------------- Do you think we should have a "Suppliers" section? I was thinking of purchasing some of those magnetic mount bases and could not find the thread on the forum. I know as time goes on it may become outdated but it would be a good reference for things like Pinholes, bases, chemicals etc.. John Pecora --------------------------------------------------------------------------------------------- I wonder if we want a manuals section. I have found that to be the hardest thing to locate when a used piece of equipment is purchased. Augie sent me a copy of his for my Ion laser. And I was reading a laser forum and someone else was looking for that same manual, whick I will copy for him. Are their any legalities associated with posting manuals here? John Pecora --------------------------------------------- If we have a disclaimer that we contacted (a person's name) and recieved permission to publish it here. This is not the easiest thing to aquire. Without it I would advise you to make a section on your own site and post a link in the links section. Oh, yeah the supplier for magnetic baes is Enco. 777c155f556a59c7336d16bb773b3939414a234e 6 358 813 2006-07-21T05:25:39Z Ron Michael 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 514 1178 2006-07-30T18:43:58Z Colin Kaminski 0 wikitext text/x-wiki Some emulsions are harder than others. Harder emulsions can take squeegeeing better than softer ones. BB-640 and PFG-01 are pretty hard and sqeegees well; Ultimate and PFG-03 are pretty soft and easily scratched. *Squeegeeing works better when a wetting agent is used. Photoflo works well, but some think it may contribute to printout. Others use the Ilford product, or just a drop of liquid soap in the final rinse. *You didn't say if you were using plates or film. For film, use a piece of clean glass to support it. Stick the film to the glass emulsion side down a la index matching and squeegee the back. The remove the film, squeegee the glass dry, and stick the film back onto the glass emulsion side up and squeegee that side last. *For glass plates, the sharp edge of the glass will make cuts in the rubber blade, which will leave streaks next time. To minimize this problem, make a jig that keeps the wiper blade in the same position relative to the plate every time. This way the cuts will always be close to the edge of the glass. 15cee72873159d5a455057f4378ac46d1f7d9785 0 574 1298 2006-08-05T18:54:57Z Ron Michael 0 /* Tips for Pulsed Ruby Holograms */ wikitext text/x-wiki ====Tips for Pulsed Ruby Holograms==== by Ron Michael When using a pulsed ruby laser and to avoid the waxy look of pulsed ruby reflection holograms try these tips: A reflection hologram is taken instead of a H1/H2 setup. The person sits further back (A safety requirement of this setup to avoid the reference beam in regards to shooting a direct reflection hologram. Details: [http://www.rotorwave.com/holography.htm Details] ). Together these contribute to a higher demand on spatial frequency resolution of the film. [http://www.rotorwave.com/holofringe.xls holofringe.xls] This when combined with the playback illumination in effect helps give a smoother image of that person with a small loss of detail. I use glamor lighting technique to enhance my subject's features. I don't use use a harsh lighting technique but opt for softer fill light in addition to the main light. (This necessitates using a multi beam reflection setup.) Glamor lighting is where a main spot beam is directed from the front, on one side, overhead at a 45 degree angle just enough to cause a slight nose shadow and a second fill light up front, on the other side, similar angle to reduce contrast of the shadows. If you take pictures underwater with a simple flash camera you get a lot of backscatter from the particles in the water. But at a 45 degree angle lighting technique (similar to glamor lighting) you get the pictures on Scuba magazines. Similar if you pancake light someone you get more of the deeper reflections of the IR lightning. So it's a technique issue as well. I strived for a natural lighting appearance of the subjects as if it was taken in white diffused light very similar to natural photography, good detail without overt razor sharpness and in using a processing chemistry like SM-6 and a reversal bleach I get the subject playback back toward red-orange for a more brighter playback. If not careful it's easy to over contrast the image, or pancake light the subject, managed to give them a dead look, able count the pores in the face and yes in that pancake shot get a very waxy look. Yet some ruby work are excellent and remain famous images. Below is a reflection hologram from a ruby laser without spatial filtering and with a collimated reference beam in a direct reflection holographic setup with two diffused object beams in a glamour lighting technique. Two object beams was split 78/16 percent. Subject is 12 to 15 inches away from film plane. Exposure was single pulse 12nsec at 45 to 60uj/cm2. Film plate is a 30cm x 40cm glass plate Agfa 8E75HD processed in SM-6 and pyrochrome bleach. Two photographs of the same hologram was taken. The hologram was illuminated by HeNe laser. When viewed directly the image appearance was sharp and less contrast and more visible detail. For example you could see the fingers holding the fish. [[Image:PulseRubyEx2.jpg]] ed29a05a571564e08dc5a5f125fc2692687500e5 6 342 685 2006-08-13T17:09:23Z Wolfgang 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 480 1110 2006-08-30T00:12:27Z Jeff Blyth 0 /* Importance of De-ionized Rinsing Water */ wikitext text/x-wiki A proper rinse is very important for making good holograms. There are a few things to consider. The first is the length of the rinse. A good rinse is long enough to remove all of active chemicals. 5 minutes is often used. ==About Water== Water is more than just H2O. Tap water starts as rain fall. This water filters down through the ground to an aquifer. From the aquifer it either comes up through a spring or is pumped up through a well. This path disolves many things into the water. Gypsom, Epsom, Calcium Chloride and salt are often encountered. Also, it is common for water to disolve traces of iron on the way to the tap. Ions in Tap Water: *Ca++ Calcium *Mg++ Magnesium *Na+ Sodium *Cl- Cloride *SO4-- Sulfate *HCO3- Hydrogen Carbonate and to a lesser extent H2CO3 and CO3--. It can also contain disolved CO2 as carbonic acid. ==Tap water rinsing== By Jeff Blyth Prolonged tap water rinsing can remove some of your AgBr with significant differences depending on time of year and the temperature of your cold water supply. Any AgBr loss causes a shift to a shorter wavelength replay in the case of reflection holograms and of course some loss in diffraction efficiency but sometimes people prefer to simply shift the color from orange-yellow to yellow-green using a hot water rinse. The result can look brighter, also any scatter from AgCl contamination can be removed because AgCl is about ten times more soluble than AgBr. Some idea of the temperature effect can be seen from this graph: [[Image:SilverSolubility.gif]] ==Importance of De-ionized Rinsing Water when "reversal" bleach is used.== By Jeff Blyth If you are using a rehalogenating bleach then tap water alone is OK but with reversal bleach it is really important to avoid soluble halide ions (ie. bromide,chloride or iodide ions) remaining in your hologram before it goes into the dichromate bleach bath. So the procedure should be: After the developer the hologram needs a good rinse under tap water to remove the developer and soluble bromide and iodide ions in it . Even if the developer had no halide ions initially, the development process means that the AgBr and AgI in the emulsion had to be broken up and turned into dark silver and soluble Br- and I-. The tap water rinse then leaves the emulsion with just chloride ions from tap water which are less of a problem to deal with later than soluble bromide or iodide ions. Before the dichromate bath is used you have to have two pre-baths of de-ionized water (DI) to remove all traces of dissolved halide ions. If you don’t do this then some of the developed up silver fails to be removed from the light-struck fringes and deposits itself back in the fringe as silver halide. This causes scatter in the finished hologram and reduces diffraction efficiency because the light struck fringes have failed to be properly cleared of AgBr. Where even experienced holographers commonly go wrong is that after removing the bleached hologram from this reversal bleach bath, they rinse it under the tap instead of first putting the hologram back in de-ionized water for a second time. This is because after leaving the bleach bath the hologram is full of silver ions in solution which can instantly form silver chloride particles with the chloride ions in tap water. So this causes scattering from inside the emulsion which cannot be wiped away even if surface silver chloride can be. After using the bleach bath you may notice a red-brown precipitate or scum in the bath. This is normal and it is actually good to have it in there. It is made up of silver chromate or dichromate which is not very soluble but is far more soluble than are the silver halides. So what this red sludge means is that your bleach bath is saturated with silver chromate in solution and any stray halide ions in solution are effectively precipitated out before they can get inside your emulsion. Even though some precipitated silver chromate may form in your gelatin layer it comes out easily in the DI bath. After this final DI bath you can then rinse the hologram in tap water to eliminate any dichromate ions if you wish, because there will be no soluble silver ions to cause trouble in a final tap water rinse. (Personally I like having a trace of dichromate in the hologram not washed out because it helps to prevent future printout. However dichromate is quite poisonous and who knows what future use your hologram may be put to particularly with young children around). ==Filtration Systems== Filtration is a good way to make large quanities of water at a known quality. There are many filter types. ===Charcoal=== Charcoal filtration passes water through activated charcoal. Charcoal is activated by using Oxygen to open millions of tiny pores in the carbon structure. The resulting surface area can exceed 1000 M^2 per gram! A charcoal filter works by adsorbing impurities it is effective in removing chlorine and carbon based molecules. '''Advantages''' *Inexpensive *Commonly Available *Removes Chlorine '''Disadvantages''' *Will not remove Nitrates or salts ===Ion Exchange=== Ion Exchange uses salt to take out all of the ions in water and replace them with Na+ and Cl- ions. Also called water softeners. These are not very suitable to rinse water. '''Advantages''' *Removes all of the Ca++ and Mg++ ions. *Inexpensive compared to DI units. *Removes upto 10 ppm of Fe. '''Disadvantages''' *Must be flushed with water daily. *The salt must be replaced frequently. *Adds lots of Na+ and Cl- ions to the water. *Leaves chlorine intact. ===Deionization=== These filters usually use a mixed bed ion exchange unit. It provides very pure water. The cartridges must be recharged by washing the ions from them. Most often they are replaced. Usually a Carbon filter and/or a softener are used ahead of a DI unit. '''Advantages''' *Very pure water. *High flow rates. '''Disadvantages''' *Medium installation costs. *Expensive to recharge and replace cartridges. ===Reverse Osmosis=== Small RO systems usually consist of 3 or 4 filters. A coarse filter, a fine filter, a charcoal filter and a membrane filter. It is the function of the last filter that gives this system it's name. In order to operate much water is used for providing the osmotic pressure. It is not unheard of to have 2 gallons of waste water for each gallon of RO water. RO units are slow to produce water so they usually have a storage tank to hold water made in off peak times. '''Advantages''' *Filters all ions to around 5ppm or better. *Filters almost all impurities. '''Disadvantages''' *Wastes lots of water. *Filter replacement is expensive. *Requires a storage tank. *Expensive ===Distillation=== Distillation evaporates water and condenses it on a cool surface leaving all of the impurities behind. It provides the purest water in a lab. '''Advantages''' *Provides the most pure water. '''Disadvantages''' *Expensive. *Low flow rates. *High energy costs. 3ffa5507f658854aa6860dc193ce38537b9367ad 6 294 479 2006-09-03T02:50:21Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 464 1078 2006-09-04T04:38:35Z Martin Mueller 0 wikitext text/x-wiki The history of photopolymers may actually go back as far as the early 19th century when French photo pioneer Nicephore Niepce (http://www.niepce.com/pages/inv1.html#) carried out experiments with light-sensitive bitumen of Judea. Previously applied by the printing industry, photopolymer materials have meanwhile become an essential part of our daily life (from adhesives to optical memories). In the late 1960s companies like Hughes, Bell, RCA, DuPont, Canon, Polaroid started introducing photosensitive polymers for holography. In the meantime a great many photopolymer systems have been developed. Generally these light-sensitive compositions were formed of a photopolymerizable monomer, an initiator system and a polymer binder. Photopolymerization may be defined as the reaction of monomers or macromers to produce polymeric structures upon light-induced initiation. In photopolymer systems designed for holography index modulation usually is caused by refractive index changes. Upon actinic radiation polymerization is being initiated within the recording layer creating thus areas of increased molecular weight, converting a monomer into a polymer. Colburn/Haines (Volume hologram formation in photopolymer materials, Applied Optics, Vol. 10, 1971, pp.1636-1637) point out: ''In general, hologram formation in photopolymers is a three-step process. First, a normal exposure is made to the interference pattern to be recorded; this initial exposure polymerizes part of the monomer, with the amount of polymerization being a function of the intensity of the illumination. Monomer concentration gradients, caused by variations in the amount of polymerization, then give rise to the diffusion of the relatively small monomer molecules from regions of higher concentration to regions of lower concentration. With the completion of the diffusion step, the photopolymer is exposed to light of uniform intensity until the remaining monomer is polymerized.'' In a holographic setup the variations of light intensity will translate into refractive index changes. So far most photopolymer materials represent almost ideal phase media. In order to achieve maximum index modulation each component needs to be adjusted to each other with regards to optimizing refractive index differences. Such criteria might equally apply to components like solvents, binders, plasticizers, surfactants etc. Photopolymers can be spectrally sensitized over a wide range of wavelengths from UV to IR. Carré/Lougnot (Photopolymers for holographic recording: from standard to self-processing materials, J. Phys.III France 3, 1993, p.1445, www.edpsciences.org/articles/jp3/ref/1993/07/jp3v3p1445/jp3v3p1445.html) distinguish four categories: "dry formulation containing a polymeric film-forming binder (substrate), a dissolved monomer and a photoinitiating system; liquid or highly viscous coating containing monomers with several reactive functions and an initiating system; dry film composition containing crosslinkable, dispersed or grafted structures or unreacted double bonds and an initiating system; polymer film composition containing sensitive groups capable of undergoing photomodification (isomerization) or photodegradation (cleavage)." In order to provide the photosensitive material with sufficient mechanical strength, many systems contain a binder material. However, the binder tends actually to lower the diffusion of the monomers within the recording layer, preventing thus full polymerization. Such systems may hence suffer from insufficient efficiency and reduced index modulation. One way to get around that issue is to subject the recording layer to a thermal treatment following the laser exposure and the subsequent UV post-exposure. The temperature rise will increase diffusion speed to enhance the degree of polymerization. Liquid post-treatment of the fully polymerized layers may be carried out to influence paramters like playback wavelength and bandwidth. While most systems used to rely on radical polymerization, there has been increasing interest in cationic photoinitiators. The latter are based on the generation of an acid, which forms upon actinic radiation and promotes cationic polymerization. Dupont makes a line of photopolymer films available for large applications. It is reported to nolonger be available for art holography markets. [http://www.dupont.com/holographics/ Dupont] Polaroid makes a line of photopolymers as well. DMP128. [http://www.dupont.com/holographics/technicalpapers.html Dupont's Technical Papers] 063799f88cc8795edd6feb0c7afc197c44b41d10 6 349 763 2007-01-05T07:30:11Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 287 453 2007-01-05T07:32:00Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 288 455 2007-01-05T07:32:30Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 339 659 2007-01-05T07:34:49Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 572 1294 2007-01-05T07:35:29Z Colin Kaminski 0 /* Thermometer Calibration */ wikitext text/x-wiki Thermometers come in a variety of types. They are used to measure the temperature of a gas, liquid or solid. ==Liquid Filled Thermometers== [[Image:LiquidThermometer.jpg]] '''Advantages''' *Accurate *Calibration is insensitive to mechanical shock. '''Dis-Advantages''' *Fragile *Difficult to insert into processes *Can not be recalibrated ==Bi-Metal Thermometers== [[Image:BiMetalThermometer1.jpg]] [[Image:BiMetalThermometer2.jpg]] '''Advantages''' *Easy to read *Easy to insert into proceses *Easy to recalibrate '''Dis-Advantages''' *Calibration is sensitive to mechanical shock ==Thermocouples== ==IR Thermometers== [[Image:IRThermometer.jpg]] '''Advantages''' *No contact is required *In-expensive *Easily measures surface temperature of solids '''Dis-Advantages''' *Only measures surface temperature ==Thermometer Calibration== For Calibrating low temperature thermometers make a bath of distilled water and crushed ice. Stir this solution for a couple of minutes and your thermometer should read 32F or 0C. Adjust as necessary. For Hi-Temperature thermometers boil distilled water. Your altitude will effect the temperature of boiling water. At sea level adjust to 212F or 100C. At 2000 ft adjust to 208F. At 4000 ft adjust to 204F. At 6000 ft adjust to 201F. at 8000 ft adjust to 197F. at 10,000 ft adjust to 194F. ==Further Reading== http://en.wikipedia.org/wiki/Thermometer 3630a814cd27e70eff73bc2ed293b8e6bb6f4699 0 197 241 2007-01-05T07:43:19Z Colin Kaminski 0 wikitext text/x-wiki Concrete is a mixture of Portland Cement, sand, gravel and water. As an engineering material it only works in compression. Any tension and the concrete will crack. Concrete structures are designed with metal bars or cloth inside to support the tension loads of the structure. Concrete can be mixed from the scratch raw materials (above) or can be bought already pre-mixed needing only the water added. When mixing concrete add just enough water to make the concrete just loose enough to be pushed into the desired form (mold). If anything, on the stiffer side is better then on the runny or loose side. Just after pouring concrete a screet is used to level the concrete to the top of the form. A screet is usually just a very straight piece of long wood. The screet is placed on both sides of the form and pushed back and forth while being pulled in one direction. This levels the concrete. The excess concrete usually overflows over the side and at the finish of the screeting process. Then after the concrete has set up partially (enough so that you are able to press one of the grave stones down into the mixture but it requires some force) a concrete float (usually aluminum or magnesium) is used to press the gravel down into the concrete and "float" the portland/sand to the top. This leaves a nice smooth top. This can be done once to serveral times and for a finer finish and a fine spray of water can be added to the top of the setting concrete just before the second or subsiquent floating proceedures. This additional water also help the curing process. It is also at this point you can press your hand into the concrete to preserve you hand print for a very long time, or sign you name in the concrete. It should be noted that concrete does not DRY. It cures. It will cure to a harder product if youkeep the surface wet for a few days. A wet carpet on the surface works well. 18cc11c5ea3fe048ee08114ca1a1def64d3cda51 0 517 1184 2007-01-05T07:45:58Z Colin Kaminski 0 wikitext text/x-wiki Staight edges, as pointed out, are to lay out straight lines and to check if things are straight and flat. Wooden materials are bad to use as staight edges as they usually have bows in them. Squares and metal rulers are good straight edges. Plastic rules are also good straight edges. A drywall square has a 4 foot straight edge with measured increments. For very long straight lines, a chalked string line (called a snap line) can be used. In expensive large straight edges can be purchased as "flat ground steel" from industrial suppliers like MSC Industrial or McMaster-Carr. Be very careful with your straight edges as they can get easily get nicks that will effect their ability to measure flatness. ==Testing a Straight Edge== If you compare any three straight edges thay can only be straight if they all match. Any two straight edges can match if they have the same curve. But, for three to match they must all be straight. 908b84de14ec2f9f306718050160d52b47145ee9 6 361 835 2007-01-07T22:31:07Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 346 721 2007-01-07T22:33:52Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 303 541 2007-01-07T22:43:44Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 313 585 2007-01-08T00:14:31Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 362 837 2007-01-15T18:09:59Z Michael Harrison 0 Updated image of the SPER light meter wikitext text/x-wiki Updated image of the SPER light meter baab0273dcdad4bfa1d0359f33d6eb62a059403d 0 191 229 2007-01-24T05:16:11Z Colin Kaminski 0 wikitext text/x-wiki ===Kris Meerlo's Coating Machine=== Some pictures from my new home made coating machine: [[Image:KrisCoatingMachine.jpg]] Some specifications: -Temp control ( roomtemp to 70 C ) -Variable speed control. -cooling with fans. For the temp control I use the amazing sauna belt from amazing discoveries incl a digital temp controller from Conrad electronics. For quick cooling off the aluminium heating plate I use harddisc drive cooling fans. I tape the heat tracing from the Sauna belt on the Alu plate with heat resistance alu tape. The movement of the meyerbar is variable. ( I "stole" some ideas for the coating machine from the internet ). And I have some ideas from Hans. ===Hanz' Coating Machine=== [[Image:HanzCoatintMachine.jpg]] One problem I have found with my machine is the following: If I use normal glass that has only been cleaned with Glassex window cleaner, the machine produces a nice and flat coating. But if I pre-treat the glass with silane, the glass becomes hydrophobic. This has a negative effect on the flatness of the coating because the gelatin wants to run of the glass in any direction it can while it is still liquid. 84181922941c8041966dea332f3b4f26ca49d0be 6 341 683 2007-01-24T05:18:09Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 314 589 2007-01-24T05:18:46Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 192 231 2007-01-24T05:25:03Z Colin Kaminski 0 wikitext text/x-wiki Coating a plate with gelatin of even thickness is a demanding task. It is quite important that the coating be of a uniform thickness. There are many methods for coating a plate listed below: [[Veil Coating (with Spin or Lean)]] [[Myer Bar Coating]] [[Spin Coating]] [[Mold Coating]] [[Coating Machines]] [[Prepping Glass]] for coating. d788fa834f701756126c0e437ee33966137483a1 0 271 389 2007-01-24T05:48:24Z Colin Kaminski 0 /* Edge Lit Holograms */ wikitext text/x-wiki See [[Setups]] for more information on making these types of holograms. ===A Hologram Defined=== hol·o·gram (hŏl'ə-grăm', hō'lə-) n. A [[Diffraction|Diffraction Pattern]] which, when properly lit, produces a three-dimensional image. Typically, holograms are made using a laser as a light source and and a very high resolution film or glass plate to record the diffraction pattern resulting from interference between light coming directly from the laser and light reflected from the object. ===Transmission hologram=== This was the one of the first holograms made. A transmission hologram is made when the reference beam and light from the object enter the recording material from the same side. The recorded interference fringes form a transmission grating which diffracts light passing through the hologram. Properties include: * looks like a blurry rainbow image when viewed with white light * viewable as a sharp image only by shining laser light through the hologram * recording material requirements are more relaxed (less resolving power is needed) * simple set-up * greater depth of the scene is possible * the scene can be projected by shining a collimated laser beam through the hologram ===Reflection hologram=== A reflection hologram is made when the reference beam and light from the object enter the recording material from opposite sides. Properties include: * viewable in regular light * very simple Denisyuk style setup can be used * finished hologram is monochromatic (a single color) for each laser color used * color can be shifted by pre or post shrink/expanding recording material ===H1 to H2 copies=== H1 refers to a first generation (master) hologram. H2 refers to a copy made from the H1. H1s are usually transmission holograms and H2s are usually reflection. They may use different recording materials. Properties include: * Somewhat complex setup requirements * Objects can be made to appear to be coming out of the plate towards the observer * Once a usable master H1 is made and the setup constructed, many copies can be produced easily ===Rainbow Holograms=== Rainbow holograms are transmission holograms which are produced in such a way as to be viewable in regular white light. Depending on the viewing angle, the color changes (hence the term rainbow) Properties include: * perspective information is lost in one axis (for example, you may not be able see a change in perspective when looking from above or below) ===Open-Aperture Transmission Hologram=== An open-aperture transmission hologram is simply a transmission hologram the has the image very close to the film plane and is designed to be viewed in white light. Properties include: *White light viewable. *Image blurs colors as the image move in front of, or behind the film plain. *2 cm usable depth of field. *The image is achromatic. ===Multiplexed holograms=== Multiplexed holograms store many different holograms on one piece of film usually as multiple exposures. Properties include: * simple animations are possible * diminishing quality as more holograms are stored ===Edge Lit Holograms=== Edge Lit Holograms have the reference beam entering the plate from one edge instead of one face. This allows the illumination to remain hidden from the observer and makes for a fairly compact display. *They are difficult to make. [http://www.media.mit.edu/spi/SPIPapers/ryder/thesis.pdf Edgelit holography:Extending Size and Color] by Ryder Sean Nesbitt ===Embossed Holograms=== Embossed holograms are made by forming a rainbow transmission hologram in thermoplastic and bonding it to a mylar mirror. It is the kind of hologram seen on credit cards. Properties include: * very low per-unit cost when mass-produced * shallow hologram depth (usually just a few millimeters) * durable and flexible * mass production can use existing equipment and technology (e.g. CD production) ===Pulsed Holograms=== Pulsed Holograms can be either transmission or reflection. The key difference is the pulsed laser emits a short, powerful pulse of light rather than a continuous beam. This pulse (about 20ns) is short enough to stop moving objects and make an image. Even bullets can be stopped with the correct setup. Most often used for portraits. * The flash photography of holography * Stability requirements are greatly diminished, allowing for holograms of people, melting ice, flowers, animals, etc. to be made * Pulse lasers are very expensive * Setup and testing can be tricky and dangerous See [[Tips for Pulsed Ruby Holograms]]. ===True Color Holograms=== [[Image:CIEDiagram.jpg]] True color holograms are a variety of reflection hologram made with more than one laser color. There have been good true-color holograms made with two, three and four colors of lasers. The resulting hologram displays the same colors as the original object. * Since true color holograms are multiplexed holograms, recording material need to be capable of holding a lot of information * Lasers and equipment can be expensive and tricky to set up [http://www.ultimate-holography.com/GB/galerieanglais2Color.html See examples by Yves Gentet] 85b7157da9bc9b9b9a1d66f8a1beed793daef9dd 0 439 1028 2007-01-25T23:39:29Z Colin Kaminski 0 wikitext text/x-wiki Mold coating is the process where you use spacers between two pieces of glass, one with a release agent, in order to get an even coating thickness. Depending on the exact chemistry desired a coating thickness is set by the spacers. A place to start is 7um. Swollen unhardened gelatin can contract on hardening by a factor of 8, but partially hardened stuff can be less than half this. #Take two identical pieces of glass. One with tape on two opposing edges. Different tape thicknesses will yield different final emulsion thicknesses. #Treat the piece of glass without the tape with Rain-X to prevent sticking. #Place a small puddle of emulsion in the center of the plate with tape on it. Make sure the emulsion does not have any air bubbles in it. With practice a known about of emulsion can be used that covers the plate but with minimal excess and overflow. #Then gently lay the piece of glass without tape and with the Rain-X (Rain-X side facing the emulsion) on top of the puddled glass as flatly as possbile. You will see the puddle of emulsion expand though th entire plate. #Place 4 black paper clamps, two on each side right over the tape. #After the gelatin has dried, minimally 3 or 4 hours, gently pull them apart. A very flat surface is left behind. ==Tips== *I would add that air bubbles in the gelatin can be removed using the edge of piece of adsorbing paper. I found bubble formation is a quite common problem when making plates. - Cristiano ===Tips from Dave Battin=== The glass I use for my mold is 1/4" mirror (back silver), while I won't call this glass optically flat, it is of optical quality. The Rain-x is the key, I put a couple drops on the mold, then buff it in, heat the mold and film plate, and meter out the emulsion. To see the emulsion do a little dance on the rain-x is really amazing! I have a "two suction cup" handle that I use to hold my plate and slowly drop/ hinge the plate along the taped edge of the mold. I then place six larger paper clamps around the perimeter My plate size is 5"x 15" and i can get 3 nice 4x5s per mold , If metered carefully (absolutely leveled mold) ,only a few drips will come off the mold ends …………. As soon as the gel sets (a few mins) I move the still slightly warm plate and mold, on to a frozen piece of granite, where it rapidly cools down. Buy the way the granite can work both ways, for both cooling, and heating! I purchased these as granite tiles a the local Depot (12"x12"), and cut them up ........ The tape I used is plain Scotch Tape and is .0025” or @ 63 microns thick. And to my surprise the film thickness came in @ .0004” or @ 10 Microns. The gelatin was Knoxx brand at a 15 grams /110 ml DI water, poured @ 70+degrees C. 7214f66546519cee8845d2bc4ce69a159faa9aed 0 469 1088 2007-01-26T04:41:38Z Colin Kaminski 0 /* JohnFP's Method= */ wikitext text/x-wiki ===Cristiano Perrucci's Method=== #- hand wash for a few a minute with sponge and dish detergent #- soak in 50% domestic bleach for 6-8 hrs #- wash in hot tap water (~45C) scrubbing with a sponge for a minute #- final wash in R.O. water for a few seconds #- dry with a towel #- final cleaning with Glassex (Windex in the USA?) this procedure works fine for MBDCG If I'm recycling old homemade plates, I start cleaning procedure from step 3 until all old emulsion has been washed out. Cleaning plates is the most boring task of DIY holographic plates, I liked to minimize time spent for this crucial step. ===Hans' Method=== I have had great results with this method: Previously I had great trouble with sticking gelatin to glass by silane'ing the glass with a solution of silane+acetone. I have found a new formula (from Bjelkhagens book) that seems to work much better for me. A mix is made with 40% silane + 45% Isopropylalcohol + 5% water. After 24 hours, this mix is further diluted with Isopropylalcohol to 5%. Then rub the glass thouroughly with this liquid and let it rest for about two hours. I then cleaned the glass further with glassex before application of the gelatin. I always take 1cc of this solution and then add 19cc of IPA. The diluted solution can be used for about two days. Just rub it on a plate with a towel. You will see a white haze on the plate. I then put the plate away for a couple of hours and clean with a ammonia based glass cleaner. If you wait more than a day before cleaning the plate with glass cleaner, the white haze becomes very difficult to remove. I have been using kitchen gloves. I also use goggles and a painter's mask with carbon filters. The undiluted Silane is nasty stuff. You don't want to get that on your skin or breathe it. Mix it in a fume cuboard if you can. I mix it always outside the house. ===Adam's Methods=== I soak my plates overnight in 10% potassium hydroxide aqueous/isopropyl solution (1 part alcohol per 6 parts of water) . I rinse them in warm tap water (rubbing with latex gloves - one side of the glass will make a sound when hydrophilic), rinse in DI/distilled water and wipe with towel paper until dry, wipe with a clean cloth (of silk for example) and blow with canned air. 2 days ago after such treatment, courtain coating (10% culinary gelatin, at 80deg.C), hardening in alum/formaldehyde (2 batches) and curing at 60deg.C I left my plates in DI water for 24 hours (to remove traces of a hardener). Today the gelatine is still fine and can be removed only by scratching with a nail. I hope it helps. The other way to clean plates would be soaking them in car battery acid solution with 10% potassium dichromate added. It worked with lab glass, but I haven't tried it for holographic plates. This mixture is supposed to be cancerogenic, so maybe it would be better to use KOH solution if possible. ==JohnFP's Method== For my standard DCG I soak the plates in 5% HydroChloric Acid at least 12 hours. I then scub them with a plastic wooly used to clean no stick pans in the Acid. I then put them in running how water and scrub them again in the hot water with the plastic wooly. I then set them in a rack and before they dry completely I wipe them with a fresh clean paper towel. It is important that there is a very little moisture on the glass during this wiping. I then blow them off with air. efa0a05f4070b968b6b88ca09951533de1dbe44d 0 229 305 2007-02-13T00:54:15Z Colin Kaminski 0 wikitext text/x-wiki In order to find the optimum exposure and development times it is possible to make exposure tests. There are many variations on the method but Graham Saxby's method works well if you have your film lying flat in a single beam reflection setup. (Any other setup will only take a slight variation using a moving slit or tape.) Calculate your best estimate at the proper exposure time. Place 4 coins on the film. Remove one coin after 1/4 of you estimate, remove one more coin after 1/2 of your estimate, remove one more coin at your estimate, remove the last coin at double your estimate and then shut off the exposure at 4 times your estimate. If you use tape, you can remove tape at the proper times. This makes strips of differing exposure, if you cut the plate across the strips and develop each piece for a different time you can see the effects of exposure and developing times. ==Some tips from ErichRose== After screwing around with one inch vertical strips I came up with my own little system: I was shooting 4x5s so I made a black cardboard mask that had one quadrant missing (~2x2.5). It was cut just a bit smaller than the plate so it would nestle in front of the plate between the edges of the plate holder, then it was tacked in place with hot glue. I started with the upper left corner, then upper right, lower right & bottom left. In other words clockwise* around the plate. I usually did 1/2 the calculated exposure, 1x, 1.5x and 2x for the first test. The beauty of the quadrants was the ease of lining up the card. I just flipped it around or rotated it. I had minimal overlap on the exposures. It also gave me a better field of view for assessing the exposure. The "one inch" strips often ended up being 3/4, 1-1/4, overlapped, a thin strip unexposed, etc. I could easily live without the fifth exposure. After a while you get a feel for how much the exposure will need to be even if one of the four isn't quite right. I also made good use of that fine point Sharpie marker and labeled all test plates immediately. And I kept good notes. Which I am re-reading twenty years later. Just wish I was going to be working again with 8E75 so I wouldn't have to do so much over agian. * It's a good habit to make a habit of always doing things in the same order: clockwise, left to right, top to bottom, etc. When working in the dim safe light this will make it easier to keep everything straight. ==Notes from Ed Wesly== *ErichRose is on the right track, by using a quadrant system. This takes into account the natural Gaussian fall-off of the spread laser beam, unlike the strip methods where the peripheries are seeing different flux energies at the edges compared to the centers. The quadrant captures the radially diminishing exposures, so that there is a realistic comparison of same intensities in the center of the plate but with different exposure times. *Another point to make is that the exposure times should be logarithmic, like the response of the eye. In other words, a series like 1", 2", 4", 8", 16" ... as appropriate would be good, or for finer tweaking, 1", 1.4", 2", 2.8", 4", 5.6", 8", 11", 16" ... d9d582474e84ba91e09b43ac97ea99ca6b50d68f 0 155 157 2007-02-28T16:28:43Z Colin Kaminski 0 /* External Links */ wikitext text/x-wiki == Biological Basis of Vision == ===The Human Eye=== Well-informed expositions on the biology and architecture of the human eye are available online, for example: [http://www.merck.com/mmhe/sec20/ch224/ch224b.html Online Merck Manual]. A broad article is available at [http://en.wikipedia.org/wiki/Eye WikiPedia]. A frequently cited reference on the retina from a neural/functional standpoint is Dowling (1987). The human eye is a direct extension of the brain; much more than a "biological camera," the eye performs pre-computation on observed imagery prior to transmitting it towards the visual cortex. In the words of Churchland and Sejnowski (1993), "[t]he primate retina transforms patterns of light on the 100 million photoreceptors into electrical signals on the mere one million axons in the optic nerve, and the 100:1 compression ratio suggests heavy-duty signal processing and information compression" (p. 148). One striking illusion that highlights visual precomputation, [http://studenthome.nku.edu/%7Edouglask/illusions/MachBands.htm Mach banding], is the incorrectly-perceived brightness at edges of differently-shaded fields. Although still incompletely understood, this may be due to lateral inhibition amongst nearby photoreceptors, resulting in high-pass filtering in the eye itself. ===Relevant Neural Regions=== In general, imagery from the right visual field (as collected by the ''left'' hemisphere of both eyes) is transmitted via the optic nerve and optic chiasm to the left hemisphere's optic tract; likewise, imagery from the left visual field travels along the ''right'' hemisphere's optic tract. We note that most of this flows to the thalamus's lateral geniculate nucleus (LGN), with another pathway to the superior colliculus. The information reaches the visual cortex, which is located at the back of the brain. The visual cortex has several regions: V1, V2, and so on, whose supposed function is beyond the scope of this discussion. However, we note two relevant and generally-supported hypotheses: '''Retinotopic Mapping in V1''' A striking series of experiments showed that regions of the visual cortex are mapped retinotopically to the observed field, that is, "neighboring cells have neighboring receptive fields" (Churchland & Sejnowski, 1994, p. 155). In a seminal experiment performed by Roger Tootell, a primate's brain was examined after fixation on a patterned bullseye-like target - when the brain was stained as a function of activity, an image of the target was clearly visible on the unfolded cortex (Tootell, Silverman, Switkes & De Valois, 1982). See a [http://neuro.med.harvard.edu/site/dh/114.jpg photograph here], from the Harvard website containing David Hubel's online vision textbook. [http://neuro.med.harvard.edu/site/dh/b23.htm section: The Architecture of the Visual Cortex.] '''Regions of V1 and V2 Correspond to Varying Degrees of Monocularity and Binocularity''' Churchland and Sejnowski (1994) state that: "For the brain to generate stereo vision, there must be means for the brain to compare retinal images ''relative to varying planes of fixation.'' Hubel and Wiesel (1963) discovered that striate cortical cells were not uniform in their response to a visual stimulus, but some cells were strongly monocular, and were flanked by other cells responding somewhat to stimuli from both eyes, though preferring one or the other, flanked in turn by cells that were binocular" (p. 197). See David Hubel's [http://nobelprize.org/medicine/laureates/1981/hubel-lecture.pdf 1981 Nobel Prize lecture]. Learn more about the visual cortex at [http://en.wikipedia.org/wiki/Visual_cortex Wikipedia]. == Depth Cues == Humans perceive imagery that falls on their retina(s) as three-dimensional when influenced by one or more ''depth cues.'' Monocular depth cues can be experienced with just one eye; binocular depth cues require two. === Monocular Depth Cues === Briefly, monocular depth cues include: *'''Relative size:''' larger objects are interpreted as being nearer the observer *'''Interposition / Overlapping:''' close objects tend to occlude far objects *'''Linear perspective (foreshortening):''' Receding parallel lines appear to meet at the horizon. *'''Aerial perspective (haze / fog):''' Blurry or foggy objects may be interpreted as distant, since haze usually blurs distant scene elements. *'''Light and shade:''' So-called "2 1/2-D" rendering uses the interplay of shape and light to suggest the three-dimensionality of objects. Note that people assume that light comes from above when viewing an image; this is the so-called ''light-from-above prior'' or ''light-from-above heuristic''. *'''Motion parallax:''' Horizontal observer movement (egomotion) "makes" near objects appear to move faster than distant objects. Note that this cue can be used to simulate egomotion, that is, in movies, animations, and true 3-D representations, moving foreground elements faster than background elements evokes the sensation of movement. *'''Accommodation (focus):''' Retinal focus provides information to your brain about the probable distance from your eye to the object you are fixating on. One issue of non-holographic 3-D displays is the so-called "accommodation / vergence conflict," in which the angular swivel of the eyes does not agree with their focus. This happens, for example, when watching a stereoscopic 3-D movie, since there are cases in which your eyes are focused at a distant screen while they are rotated inwards to gaze at a very close scene element. *'''Texture Gradient:''' As in a field of wheat, the perception of a textured region is a function of distance. A variety of [http://www.sapdesignguild.org/resources/optical_illusions/index.html optical illusions] prey upon the assumptions your mind makes about interpreting monocular depth cues. ===Binocular Depth Cues (Stereopsis)=== The average interpupillary distance is approximately 6-6.5 cm. In normal circumstances, this leads to each eye observing a different 2-D field. The brain interprets these differences for depth information, such as (De Valois & De Valois, 1990): *'''Vergence:''' The angular "swivel" of the eyes while gazing at an object provides a strong cue regarding the depth of that object. *'''Positional Disparity:''' A large-scale illustration of positional disparity is observed by holding one's outstretched index finger and observing the relative motion of your finger and the background when viewed alternately by your left and right eyes. [http://en.wikipedia.org/wiki/Stereopsis Wikipedia: Stereopsis] *'''Phase Disparity of Frequency Components:''' There is evidence suggesting that the brain is sensitive to the phase difference of the frequency components of an image, which has a different magnitude, of course, than displacing the sine wave component itself (De Valois & De Valois, 1990, p. 302) *'''Orientation Disparity:''' Orientation disparity refers, for example, to the different angle a line makes on each retina when gazing at a line pitched toward or away from the observer. *'''Spatial Frequency Disparity:''' The separable existence of this cue may still be in debate. Spatial frequency disparity is the difference in spatial frequency for scene elements that are, for example, at varying depths from the observer (Halpern et al, 1987). For example, pitching a single-frequency grating at an angle to the observer yields different perceived spatial frequencies in each eye (De Valois & De Valois, 1990, p. 307). The collection of potential disparities are called ''stereopsis.'' '''An Implication of Random-dot Stereograms''' Note that the brain does not require local stereopsis to perceive depth; global stereopsis "can occur without monocular contours" (De Valois & De Valois, 1990, p. 314). For example, Julesz's (1971) random-dot stereograms present two views that appear, in a monocular sense, like disorganized spatial noise. However, the brain is able to fuse the two images into a scene containing depth - perhaps via the global low-freqency content in the imagery. ==Guidelines for Effective 3-D Imagery== ===Rules of Thumb for Particular Display Media=== One implication of the preceding discussion is that it is best to match subject matter to the display medium and intended observation environment. Experts in the following media are invited to add their own rules of thumb: * Holographic stereograms * Cylindrical multiplex holograms * Quasi-holographic electro-optical displays ===Bandlimiting Can Decrease Interview Aliasing=== Holographic stereograms and other discrete-"view" 3-D displays can exhibit motion artifacts due to interview aliasing. For example, image points far from the image surface appear to jump to neighboring views during egomotion if they are sampled or reconstructed improperly. Holography researcher Michael Halle (1994) discusses these constraints, which apply in particular to holographic stereograms and non-holographic parallax displays. In short, interview aliasing can be mitigated by intentionally blurring scene elements distant from the image surface. ===Understand Your Medium's Focus Characteristics=== Of course, different 3-D display media use different methods to reconstruct 3-D light fields. For example, some holograms are highly astigmatic, putting the horizontal and vertical foci at very different surfaces in or beyond the 3-D scene. The family of horizontal parallax only (HPO) holograms discards some or all vertical parallax information (De Bitetto, 1968; Benton, 1969; De Bitetto, 1969; Benton, 1977). The long-term effects of viewing astigmatic display media, such as HPO holograms, are not widely known in the display community, and references to thoughtful work in the area are appreciated. While not holographic, the variety of electronic 3-D display technologies also vary in their focus characteristics. They range from volumetric displays, whose true voxels in (''x'', ''y'', ''z'') space elicit proper vergence and accommodation cues (Favalora et al, 2005) to experimental "highly-multiview" HPO systems (Favalora, 2005) and lenticular-sheet displays which are HPO ''and'' typically project very discrete infrequently sampled horizonal parallax information. Members of the former MIT Media Laboratory's Spatial Imaging Group explore the importance of choosing the correct scene-sampling and reconstruction geometries as a function of factors including the intended observation point and propose computational predistortion methods for dealing with these issues (Halle, Benton, Klug, & Underkoffler, 1991). == References == <small> *Churchland, P. & Sejnowski, T. J. (1994). ''The Computational Brain''. Cambridge, Mass.:The MIT Press. ISBN 0262531208 *Benton, S. A. (1969). Hologram Reconstructions with Extended Light Sources, ''J. Opt. Soc. Amer. 59'', 1545A. *Benton, S. A. (1977). White-light transmission/reflection holographic imaging. In E. Marom, A. Friesem, & E. Wiener-Avnear (Eds.), ''Applications of Holography and Optical Data Processing'' (pp. 401-409). *De Bitetto, D. J. (1968, March 1). Bandwidth reduction of hologram transmission systems by elimination of vertical parallax. ''Applied Physics Letters, 12''(5), 176-178. *De Bitetto, D. J. (1969, August). Holographic Panoramic Stereograms Synthesized from White Light Recordings. ''Applied Optics, 8''(8), 1740-1741. *De Valois, R. L. & De Valois, K. K. (1990). ''Spatial Vision''. Oxford: Oxford University Press. ISBN 0195050193 *Dowling, J. E. (1987). ''The Retina: An Approachable Part of the Brain''. Cambridge, MA: Harvard University Press (Belknap Press?). ISBN 0674766806 *Favalora, G. E. (2005, August). Volumetric 3D Displays and Application Infrastructure. ''Computer, 38''(8), 37-44. [http://www.greggandjenny.com/gregg/IEEE_Computer_Favalora.pdf PDF] *Favalora, G. E., Chun, W., Cossairt, O. S., Dorval, R. K., Halle, M., Napoli, J., & Thomas, M. (2005), "Scanning optical devices and systems," U.S. Pat. App. US2005/0285027A1, filed Feb. 15. *Halle, M. W., Benton, S. A., Klug, M. A., & Underkoffler, J. S. (1991). The Ultragram: A Generalized Holographic Stereogram. In S. A. Benton (Ed.), ''Practical Holography V'' [Proc. SPIE-IS&T Electronic Imaging, SPIE Vol. 1461] (pp. 142-155). [http://citeseer.ist.psu.edu/halle91ultragram.html CiteSeer] *Halle, M. (1994). Holographic stereograms as discrete imaging systems. In S.A. Benton (Ed.), ''Practical Holography VIII'' [Proc. SPIE] Vol 2176, (pp. 73-84). Bellingham, WA. [http://splweb.bwh.harvard.edu:8000/pages/ppl/halazar/pubs/discrete_spie94_preprint.pdf Preprint PDF] *Halle, M. (1997, May). Autostereoscopic displays and computer graphics. ''Computer Graphics,'' ACM SIGGRAPH, 31(2), 58-62. [http://web.media.mit.edu/~halazar/autostereo/autostereo.html HTML and PDF versions.] *Halpern, D. L. et al (1987). What causes stereoscopic tilt from spatial frequency disparity. ''Vision Res., 27''(9), 1619-1629. *Hubel, D. H. & Wiesel, T. N. (1963). Shape and arrangement of columns in cat's striate cortex. ''Journal of Physiology, 165'', 559-568. *Julesz, B. (1971). ''Foundation of cyclopean perception''. Chicago: University of Chicago Press. *Okoshi, T. (1976). ''Three-Dimensional Imaging Techniques''. Academic Press. ISBN 0-12-525250-1 *Ratliff, F., Milkman, N., & Rennert, N. (1983). Attenuation of Mach bands by adjacent stimuli. ''Proc Natl Acad Sci U S A 80''(14), 4554-8. [http://radiology.rsnajnls.org/cgi/ijlink?linkType=ABST&journalCode=pnas&resid=80/14/4554 Abstract and Article PDF] *Shepherd, G. M. (2003). ''The Synaptic Organization of the Brain''. Oxford University Press. ISBN 019515956X *Tootell, R. B. H., Silverman, M. S., Switkes, E., & De Valois, R. L. (1982). Deoxyglucose analysis of retinotopic organization in primate striate cortex. ''Science, 218'', 902-904. </small> == External Links == * H. Kolb et al, ''[http://webvision.med.utah.edu/ Webvision: The Organization of the Retina and Visual System]'', John Morgan Eye Center, University of Utah (accessed 28 May 2006) * [http://www-staff.lboro.ac.uk/~mmtw/holopaperWeb.pdf Brief Survey on Three-Dimensional Displays: from Our Eyes to Electronic Hologram] 0d0184f021073a6f8b834fb259c5e1a9a0abd0cc 0 413 976 2007-03-03T07:28:03Z Otto Oberon Outlier 0 High power laser time delay. wikitext text/x-wiki '''Laser Safety.''' [http://www.repairfaq.org/sam/lasersaf.htm#saftoc Laser Sam's Laser Safety] is a must read! [[Laser Alignment Safety]] from LBL. ==Eye Hazards== [[Image:TheEye.gif]] Most importantly, any laser, even a 1/2 milliwatt laser pointer can be dangerous to [[The Eye]]s. Never point a laser directly in anyone's eye. Also it is very easy to catch a laser reflection off of something into your eye. Wear Laser protective glasses whenever possible and avoid directing the beam to any shiny surfaces. When a laser beam reflects off a flat surface it becomes a spot that your eye must avoid. When it reflects of a cylindrical surface it becomes a line. While, it is a lower power density it is also large and harder to avoid. If you reflect off a spherical surface it becomes a very large object to avoid. Try, whenever posible, to make any mounts black and aim optics at the lowest power possible. Higher power lasers (generally 5 Mw or more) should have a time delay connected to the ON switch. Often a key is required to prevent the high power laser from accidentally being activated. When using high power lasers, turn the energy down as low as possible when aligning optics. ===Eye Hazards for Pulsed Lasers=== It is important to calculate the maximum power density of the object beam when making a pulsed portrait. Use large diffuser plates to enlarge the light source. Here is some more information about [[The Eye]]. ===Infra-Red Eye Hazards=== Holographic lasers can be sources of 808nm light, 1064nm light in both continuous and pulsed modes. Most people can not detect any light at these frequencies. This makes verifying a non-function laser quite important. It is conceivable that light is emanating from a laser that appears dead. The 532nm beam can be contaminated with IR light in some circumstances. Mirrors can be designed to reflect the 1064nm light and not the 532nm light (or visa versa). It is important to send any un-wanted IR light to a beam dump. ===Flash Lamp Eye Hazzards=== Flash Lamps can emit light from the UV to the Far IR. This light is very short but can cause considerable damage. Always shield flash lamps for testing. This helps protect from light and from lamp explosion. '''Do not operate flash lamps without a guard.''' ==Electrical Hazards== Quite a few laser use high voltage power supplies. Know your laser and it's power supply. Even some small HeNe lasers use high voltage capacitors that can discharge even when the laser is unplugged. Practice [[Safe Electrical Procedures]]. Grounding is a very important aspect of safety in power supplies. Frayed cables, loose parts, motor or coil windings can be a source for an electrical fault. (metal etc becoming energized with voltage) With proper grounding this will cause a short as the ground takes the current back without much resistance which will trip a circuit breaker either in the unit or building. Unfortunately, some buildings may not be wired correctly regarding ground safety or the wall outlet may not actually have a ground wire that runs back to the electrical circuit ground point and earth ground. Such ungrounded conditions will allow the voltage to remain present and if you become grounded by some condition and you become part of that path then you will take the current load. Additionally high voltage (HV) used in the laser system also for the same reason should be grounded so that if a fault occurs it's current will induce a load that causes the power supply to disconnect via it's circuit breakers. It is the voltage difference that causes current to flow and you don't want to be in that path, so it's best to have the laser head hard grounded (at the same equip-potential) to the power supply and the power supply hard grounded to the building etc so that any faults trips breakers which prevent fires and hopefully electrocutions. Ground fault interrupters are better at breaking the current sooner since they operate at milliamp levels of current on the ground wire. More information about GFI at Sam's [http://www.codecheck.com/gfci_principal.htm GFI] Always design circuits that have large capacitors so they automatically discharge if left unused. A 1000V potential will easily jump 1cm. A 3000V potential will jump 3cm. [[http://www.lbl.gov/ehs/pub3000/CH08.html LBLs excellent guide for electrical safety]] ===How Much Current is Dangerous?=== *'''Electrical Current''' -- '''Biological Effect''' *1 mA threshold for feeling *10-20 mA voluntary let-go of circuit impossible *25 mA onset of muscular contractions *50-200 mA ventricular fibrillation or cardiac arrest ===Types of Damage Caused by Electrical Hazards=== From LBL. ====Electrical Shock==== Accidental contact with EXPOSED electrical parts operating at a VOLTAGE greater than 50 volts to ground, and having a current greater than 5 milliamperes, can cause serious injury or death. Fatal ventricular fibrillation of the heart can be triggered by a current flow of as little as several milliamperes. Severe injuries, such as deep internal burns, can occur even if the current does not pass through the vital organs or nerves. ====Delayed Effects==== Damage to the internal tissues may not be apparent immediately after contact with the current. Delayed internal tissue swelling and irritation are possible. Prompt medical attention can help minimize these effects and avoid death or long-term injury. ====Arc-Flash==== When an electric current passes through the air between two conductors, the temperature can reach 35,000°F. Exposure to these extreme temperatures can result in life threatening burns. The majority of hospital admissions due to electrical accidents are from arc-flash burns, not electrical shocks. Arc-flashes can and do kill at distances in excess of 10 ft. ====Arc Blast==== The tremendous temperatures of the arc cause an explosive expansion of both metal and the surrounding air in the arc path. For example, copper expands by a factor of 67,000 times when changed from a solid into a vapor. The dangers of this explosion are of high blast pressure wave, high decibel levels of sound and high velocity shrapnel. Finally the material and molten metal is expelled away from the arc at speeds exceeding 700 miles per hour. Arc blasts often cause severe injuries and death. ====Other Burns==== Other burns suffered in electrical accidents are of two basic types: electrical burns and thermal contact burns. In electrical burns, tissue damage (whether skin deep or deeper) occurs because the body is unable to dissipate the heat caused by the current flow. Typically, electrical burns are slow to heal. Thermal contact burns are those normally experienced from skin contact with the hot surfaces of overheated electric conductors. ===Proper Procedures for Clearing High Voltage Circuits=== ===Proper Procedures for Testing Live High Voltage Circuits=== ===Laser Sam's Safety Tips for High Voltage Work=== *Author: Samuel M. Goldwasser *Copyright (c) 1994, 1995, 1996, 1997, 1998 All Rights Reserved Reproduction of this document in whole or in part is permitted if both of the following conditions are satisfied: *This notice is included in its entirety at the beginning. *There is no charge except to cover the costs of copying. ------ The purpose of this set of guidelines is not to frighten you but rather to make you aware of the appropriate precautions. Repair of TVs, monitors, microwave ovens, and other consumer and industrial equipment can be both rewarding and economical. Just be sure that it is also safe! *Don't work alone - in the event of an emergency another person's presence may be essential. *Always keep one hand in your pocket when anywhere around a powered line-connected or high voltage system. *Wear rubber bottom shoes or sneakers. An insulated floor is better than metal or bare concrete but this may be outside of your control. A rubber mat should be an acceptable substitute but a carpet, not matter how thick, may not be a particularly good insulator. *Wear eye protection - large plastic lensed eyeglasses or safety goggles. *Don't wear any jewelry or other articles that could accidentally contact circuitry and conduct current, or get caught in moving parts. *Set up your work area away from possible grounds that you may accidentally contact. *Have a fire extinguisher rated for electrical fires readily accessible in a location that won't get blocked should something burst into flames. *Use a dust mask when cleaning inside electronic equipment and appliances, particularly TVs, monitors, vacuum cleaners, and other dust collectors. *Know your equipment: TVs and monitors may use parts of the metal chassis as ground return yet the chassis may be electrically live with respect to the earth ground of the AC line. Microwave ovens use the chassis as ground return for the high voltage. In addition, do not assume that the chassis is a suitable ground for your test equipment! *If circuit boards need to be removed from their mountings, put insulating material between the boards and anything they may short to. Hold them in place with string or electrical tape. Prop them up with insulation sticks - plastic or wood. *If you need to probe, solder, or otherwise touch circuits with power off, discharge (across) large power supply filter capacitors with a 2 W or greater resistor of 100 to 500 ohms/V approximate value (e.g., for a 200 V capacitor, use a 20K to 100K ohm resistor). Monitor while discharging and/or verify that there is no residual charge with a suitable voltmeter. In a TV or monitor, if you are removing the high voltage connection to the CRT (to replace the flyback transformer for example) first discharge the CRT contact (under the insulating cup at the end of the fat red wire). Use a 1M to 10M ohm 1W or greater wattage resistor on the end of an insulating stick or the probe of a high voltage meter. Discharge to the metal frame which is connected to the outside of the CRT. *For TVs and monitors in particular, there is the additional danger of CRT implosion - take care not to bang the CRT envelope with your tools. An implosion will scatter shards of glass at high velocity in every direction. There is several tons of force attempting to crush the typical CRT. Always wear eye protection. While the actual chance of a violent implosion is relatively small, why take chances? (However, breaking the relatively fragile neck off the CRT WILL be embarrassing at the very least.) *Connect/disconnect any test leads with the equipment unpowered and unplugged. Use clip leads or solder temporary wires to reach cramped locations or difficult to access locations. *If you must probe live, put electrical tape over all but the last 1/16" of the test probes to avoid the possibility of an accidental short which could cause damage to various components. Clip the reference end of the meter or scope to the appropriate ground return so that you need to only probe with one hand. *Perform as many tests as possible with power off and the equipment unplugged. For example, the semiconductors in the power supply section of a TV or monitor can be tested for short circuits with an ohmmeter. *Use an isolation transformer if there is any chance of contacting line connected circuits. A Variac(tm) (variable autotransformer) is not an isolation transformer! However, the combination of a Variac and isolation transformer maintains the safety benefits and is a very versatile device. See the document "Repair Briefs, An Introduction", available at this site, for more details. *The use of a GFCI (Ground Fault Circuit Interrupter) protected outlet is a good idea but may not protect you from shock from many points in a line connected TV or monitor, or the high voltage side of a microwave oven, for example. (Note however, that, a GFCI may nuisance trip at power-on or at other random times due to leakage paths (like your scope probe ground) or the highly capacitive or inductive input characteristics of line powered equipment.) A GFCI is also a relatively complex active device which may not be designed for repeated tripping - you are depending on some action to be taken (and bad things happen if it doesn't!) - unlike the passive nature of an isolation transformer. A fuse or circuit breaker is too slow and insensitive to provide any protection for you or in many cases, your equipment. However, these devices may save your scope probe ground wire should you accidentally connect it to a live chassis. *When handling static sensitive components, an anti-static wrist strap is recommended. However, it should be constructed of high resistance materials with a high resistance path between you and the chassis (greater than 100K ohms). Never use metallic conductors as you would then become an excellent path to ground for line current or risk amputating your hand at the wrist when you accidentally contacted that 1000 A welder supply! *Don't attempt repair work when you are tired. Not only will you be more careless, but your primary diagnostic tool - deductive reasoning - will not be operating at full capacity. *Finally, never assume anything without checking it out for yourself! Don't take shortcuts! [http://www.repairfaq.org/REPAIR/F_tshoot.html More great inforamtion from Laser Sam's!] ==Causes of Laser Accidents== '''Some Common Causes of Laser Accidents from LBL.''' *Not wearing protective eyewear during alignment procedures *Not wearing protective eyewear in the laser control area *Misaligned optics and upwardly directed beams *Equipment malfunction *Improper methods of handling high voltage *Available eye protection not used *Intentional exposure of unprotected personnel *Lack of protection from nonbeam hazards *Failure to follow the AHD *Bypassing of interlocks, door, and laser housing *Insertion of reflective materials into beam paths *Lack of preplanning *Turning on power supply accidentally *Operating unfamiliar equipment *Wearing the wrong eyewear ==Laser Classes== [http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?FR=1040.10 Laser Classification Law] ===Class I=== Laser usually contained within the product and considered non- hazardous. Laers are less than .4 mw and require no labeling. Laser printers, CD players, DVD players ===Class II=== Visible laser or laser system that cannot cause eye damage unless viewed directly for an extended period of time, or with magnifiers, binoculars, or telescopes. Laser power .4 mw to 1mw. Bar code scanners ===Class IIa=== Laser Power is less than 1mw. Labled: Caution - Do not stare into beam. ===Class IIIa=== Laser that normally does not present a risk of injury if viewed momentarily with an unaided eye, but may present a greater risk if viewed using magnifiers, binoculars, or telescopes. Laser Power < 5 mw. Labled:CAUTION - Laser Radiation - Do Not Stare into Beam or View Directly with Optical Instruments. Laser pointers ===Class IIIb=== Laser can cause eye damage if viewed directly. Laser power < 500 mw. Labled: DANGER - Laser Radiation - Avoid Direct Exposure to Beam Laser light shows, Industrial lasers, Research lasers. ===Class IV=== Laser may cause severe eye injury with short duration exposure to the direct or reflected beam. May also cause severe skin damage and present a fire hazard. Laser Power: > 500 mw. Labled - DANGER - Laser Radiation - Avoid Eye or Skin Exposure to Beam. Laser light shows, Industrial lasers, Research lasers ==Lasers and the FDA== All laser devices distributed for both human and animal treatment in the U.S. are subject to Mandatory Performance Standards. They must meet the Federal laser product performance standard and must submit an "initial report" to CDRH's Office of Compliance prior to distributing the product (see 21 CFR 1000-1040.11). This performance standard specifies the safety features and labeling that all laser products must have in order to provide adequate safety to users and patients. A laser product manufacturer must certify that each model complies with the standard before introducing the laser into U.S. commerce. This includes distribution for use during clinical investigations prior to device approval. Certification of a laser product means that each unit has passed a quality assurance test and that it complies with the performance standard. The firm that certifies a laser product assumes responsibility for product reporting, recordkeeping, and notification of defects, noncompliances, and accidental radiation occurrences, as specified in sections 21 CFR 1000-1010. A certifier of a laser product is required to report the product via a Laser Product Report submitted to CDRH. Reporting guides and related regulatory information are available from the DSMA web site at: http://www.fda.gov/cdrh/devadvice. Distribution of any certified laser products internationally would also require submission of the report. '''FDA's Authority''' The FDA has the authority to regulate all kinds of lasers. Under the Medical Device Amendments to the Federal Food, Drug, and Cosmetic Act, the agency regulates lasers used in medicine. And under the Electronic Product Radiation Control Provisions of the act, the FDA regulates both medical and nonmedical lasers such as those used to solder circuits in factories, to scan groceries in a supermarket, or to entertain a crowd with a light show in the night sky. The FDA may inspect manufacturers of laser products and require the recall of products that don't comply with federal standards or that have radiation safety defects. The agency also may test laser products and inspect displays of laser light shows to ensure the public is protected. Producers of laser light shows are required to tell the FDA where they are planning a display so that the agency can inspect it if possible and take action if required. In 1995, the FDA, working with the Federal Aviation Administration, issued a moratorium that remains in effect on outdoor laser light shows in and near Las Vegas. The action, which affects Clark County, Nev., was taken after airline pilots reported experiencing temporary visual impairment during flights into or out of the county's three airports. The FDA requires that labeling on most laser products contain a warning about radiation and other hazards and a statement certifying that the laser complies with FDA safety regulations. The label must also state the power output and the hazard class of the product. The FDA recognizes four major hazard classes (I to IV), including two subclasses (IIIa and IIIb), of lasers--ranging from those that pose no known hazard to those that pose serious danger if used improperly. The higher the class, the more powerful the laser. Class I laser products, for example, include laser printers and CD players, which are not considered hazardous because the laser radiation is contained within the product. Class IIIb and class IV laser products are very powerful and permit ready access to the laser radiation, which can cause eye or skin injury. Research and industrial lasers and laser light show projectors fall into these classes. Class IIIb and class IV laser light show projectors may be sold only by or to individuals or firms that have obtained approval from the FDA. b005edc7417ddcb5733b48019d0935ee1a42bd71 0 242 331 2007-03-14T15:29:24Z Colin Kaminski 0 Greenies wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Galvanography''' - technique of electroplating a gelatin relief image created photographically to produce a photomechanical printing plate. *'''Gamma''' - measurement used in sensitometry to describe the angle made between the straight line portion of the characteristic curve of the photograph emulsion and the base of the graph. The gamma is the tangent of the angle so formed. *'''Gelatin filters (gells) - filters cut from dyed gelatin sheets and held in front of the lens or studio light.''' *'''Gelatin sugar process''' - daylight printing process using paper with a sugar and dichromate coating, which hardens on exposure to light. *'''Ghost images''' - bright spots of light, often taking the shape of the aperture, which appear in the camera viewfinder or in the final photograph when a lens is pointed at a bright light like the sun. Ghost images have been almost eliminated through the use of multi layer coatings of the lens elements. *'''Glaze''' - glossy surface produced on some (non resin coated) printing papers. It is achieved by placing a wet print to to a heated drum or clean polished surface. Glazed print produce denser medium blacks than their matte counterparts. *'''Gold chloride''' - soluble chemical used in gold toners. *'''Gold mean''' - compositional technique used to determine the "ideal" position of the main subject in the frame. It is based on creating a rectangle from a square. A line drawn from the center of one side of the square to the opposite corner becomes the radius of an arc. The side of the square is then protracted until it meets the arc, and from this point a rectangle is constructed. The side of the square which remains in the rectangle indicates the point at which the subject should be placed. *'''Gray card''' - card with an 18 percent gray tint (reflectance) used to determine exposure by taking a meter reading from subject light reflected by the card. *'''Greenies''' - Slang, These are often found in DCG processing and appear as a green blob in the image. *'''Gum arabic''' - water soluble gum obtained from the Acacia tree and used in coatings of a number of photographic processes. *'''Gum bichromate''' - contact printing process once very popular for the manipulative, impressionistic effects it makes possible. Drawing paper is coated with a mixture of gum, potassium bichromate and a pigment of any chosen color. This is then exposed to light behind a negative. Also known as the photo aquatint process. Gum platinum process - combination of gum and platinum printing. a1b7c86b4aaef37ebfbfcb3ab30fd5a0a3d1b33d 0 482 1114 2007-03-15T23:48:09Z Ron Michael 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 497 1144 2007-03-25T02:55:41Z Colin Kaminski 0 wikitext text/x-wiki Here is a list of tips for using basic sho tools to work in holography. It is not comprehensive but it should be enough to get you started with a new tool. *[[Glass Cutter]]- For scoring and breaking glass sheet. *[[Glass Grinder]]- For shaping and smothing glass edges. *[[File]] - For removing small amounts of material. *[[Rasp]] - For removing material more quickly than a file. *[[Knife]] - For marking, cutting and shaving. *[[Scraper]] - For finishing and leveling *[[Square]] - To layout lines and general set up. *[[Straight Edge]] - To layout lines and for set up. *[[Hack Saw]] - To cut metal. *[[Hand Tap]] - To thread holes. *[[Hand Die]] - To thread rods. *[[Drill Bits]] - To drill Holes. *[[Reamers]] - To make accurately sized and very round holes. *[[Drill Press]] - To make precise holes. *[[Dremel Tool]] - High speed rotary tool. *[[Router]] - For making slots and forming edges. *[[Table Saw]] - To cut large material into smaller pieces. Can also groove. *[[Jig Saw]] - To cut shapes from thin materials. *[[Skill Saw]] - A hand held version of a table saw. *[[Band Saw]] - To make resaw larger stock or make curved cuts. *[[Jointer]] - To clean an edge from a band saw or table saw. *[[Mill]] - To cut precice edges or slots. *[[Lathe]] - To cut precise round shapes. *[[Belt Sander]] - To shape small parts or finish surfaces. *[[Bench Grinder]] - To shape metal parts by hand. *[[Concrete Basics]] - Many tools can be made from concrete. *[[Power Tool Safety]] - Don't hurt yourself we like you! *[[Thermometer]] *[[Epoxy]] c625293bb960fa7f055922265481fed14639fbe3 0 225 297 2007-04-16T11:05:41Z Michael Harrison 0 spellchecking wikitext text/x-wiki Epoxy is different from most glues in that it is a mechanical bond. It will bond to most rough surfaces. To glue metal first sand with 80 grit then wash with acetone. ==Mixing Epoxy== Epoxy is a two part glue. There is a resin and a hardener. It is very important to have an even mixing between the two parts. For very small amounts mixing with a plastic stick on a piece of wax paper or plexiglass works well. Avoid using wood as it can absorb the chemicals differentially. Scrape the entire amount of glue off the mixing pallet often and mix to insure the epoxy nearest the pallet gets mixed in. For slightly larger amounts a paper Dixie cup works well. Make sure to scrape the sides and the bottom while mixing. 45 seconds of stirring and 15 seconds of scraping is a good rule of thumb. For very large amounts there are drill attachments and instructions are included with their purchase. For large amounts it is good to use a respirator. ==Calculating Epoxy Needed for a Fabric Layup== -from West Systems This formula will help you estimate the amount of mixed epoxy needed to wet out fiberglass cloth (assuming a resin-to-fiber ratio of 50:50) and apply three rolled epoxy coats to fill the weave of the cloth, i.e. "fill coats." The formula includes a waste factor of approximately 15%; however, more (or less) may be needed depending on the job and personal application technique. The epoxy is applied at standard room temperature, approximately 72° F. Gallons of mixed epoxy=A×[(Wf×0.00085)+0.0075] Where: A=Total area covered by fiberglass. Units are in square feet (ft^2) Wf =Total weight (W) per square yard of fiberglass (f) cloth used in laminate. Units are in ounces per square yard (oz/yd^2), i.e. 6 oz fiberglass cloth weighs 6 oz/yd^2. [http://www.crosslinktech.com/calculationaids.htm Epoxy Mixing Calculations] 0f28565ccfb06b1040a280db0e56a913fc2b1ae8 0 256 359 2007-04-25T05:34:07Z Colin Kaminski 0 wikitext text/x-wiki The color of a hologram can change as the humidity changes. Efforts have been made to epoxy glass plates to the back, glue Oracal to the back and coat the back with cyanoacrylate glues. Jeff Blyth offers a chemical method: ---- One way to stop something breathing is to strap it up tightly. The easiest way to do this is to strap it up with chromium oxygen bonds. Inevitably strapping up leads to contraction. A bonus is that using dichromate can lead to a more hydrophobic gelatin. To get a longer replay wavelength than the 532nm pulse I suppose this is a bit awkward. Shooting the plates in a very dry state helps. The processing chemistry can also help but I appreciate that this must not reduce brightness. Jeff ---- The answer I think is to thoroughly post harden the gelatin for ever. So put a test hologram in a solution of ~5% ammonium dichromate, squeegee off excess drips, blow dry it ,and leave it out in sunshine all day. If you leave it like this without rinsing it will be extremely resistant to any future print out but it might be prudent to rinse out any soluble salts. This post hardening procedure will cause some final but permanent contraction so you would just need to do tests to compensate by adjusting the swelling state for your initial laser exposure of course. My tests on this method allowed the pictures to be viewed in or out of water. So your customers could then view the holograms underwater in their swimming pools ! Jeff ---- Yes I am glad to report a successful experiment last night that left sunlight completely out of it. I took 2 bright bleached Denisyuk holograms, one on a BB640 plate and the other on a Slavich PFG-03M The plates were first dipped vertically into a solution of 7% ammonium dichromate in DI water so that they were only partially covered . After about 2 minutes they were wiped and the dipping solution had 1 % glycerol added to the 7% ammonium dichromate so that other sections of the plates were then treated with this solution. Finally a fresh 7% ammonium dichromate solution was prepared with 2% conc. sulphuric acid. So I finished up with 4 striped sections on a plate. 1) Untreated 2) 7% Ammonium dichromate in DI 3) 7% Ammonium dichromate in DI + 1% glycerol 4) Ammonium dichromate in DI + 2% conc sulfuric acid. Plates were blown in cool air till touch dry and then placed in a preheated oven at 110 C for 12 hours. Then plates were both cooled and washed in cold running tap water for 2 minutes and then dried. Results: Dry plates Stripes 1,2, and 3 showed bright images with no indication of loss of brightness except perhaps stripe (3) may have lost a little. Stripe (4) was completely ruined and out of the running. Plates soaked for 10 minutes in tap water at ~20C. Stripes 2 and 3 showed good clear images still. The BB640 plate had changed color from yellow green to light orange. The PFG-03M had changed hardly at all!... from light yellow to golden yellow. (In view of the notorious softness of this brand it was a surprise to find it had hardened up even better than the BB640 ) So this hardening method does effectively strap up the gelatin film so tightly that it cannot “breathe” and change its color with ambient humidity. Note: This was done on bleached finished holograms. It cannot be used on unbleached reflection ones, the colloidal silver would have to be converted to AgBr first. Jeff 1dc28afe34e9c033367833bcd2ba0d12f3a564bb 0 273 393 2007-05-01T04:09:12Z Otto Oberon Outlier 0 Added Frequency doubling wikitext text/x-wiki [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- This is a dictionary of Holographic terms. It has been compiled by the members of the Holography Forum for the last few years. Additions and suggestions are welcome. Further reference can be found in the [[Books]] section. ---- Things to add... Wiener prism Sagitta Sagittal Plane Tangental Plane Kerr Medium KTP, etc YAG Nd:YAG Nd:Glass Flash Lamp KLM Ti:Al2O3 Cr:LiSAlF6 - CrLiSAF AlGaInP diode Uranium Nitrate - chemical used in toners and developers. Time-Smear plate (plate) holder settling settling time splitter - see beam splitter expose exposure table - See optic bench safe light (development/chemical) tray developer rinse Photoflo object (when used in terms like 'object beam') reference squeegee play back TEA swell/swelling (of emulsion) etalon first surface mirror HOE (holographic optical element) immersion lens Liquid lens Nd:YAG laser DPSS laser Pulsed laser Q-Switched laser CW (continuous wave) Diode Laser denominator numerator Phase hologram reversal bleach rehaloginating bleach physical development Colloidal development Printout post developing Blink reflex (also known as aversion response) is the closure of the eyelid or movement of the head to avoid an exposure to a noxious stimulant or bright light. A carcinogen is an agent potentially capable of causing cancer. A continuous wave (cw) is the output of a laser which is operated in a continuous rather than pulsed mode. A controlled area is an area in which the occupancy and activity of those present is subject to control and supervision for the purpose of protection from radiation hazards. The cornea is the transparent outer coat of the human eye, covering the iris and the crystalline lens. The cornea is the main refracting element of the eye. Diffuse reflection is the change of the spatial distribution of a beam of radiation when the beam is reflected in many directions by a surface or by a medium. An embedded laser is enclosed in a laser system and has an assigned class number higher than the inherent capability of the laser system. The laser system's lower classification is appropriate because of the engineering features that limit accessible emission. An enclosed laser is contained in a protective housing. Opening or removing the protective housing provides additional access to laser radiation above the applicable MPE. (An embedded laser is a type of enclosed laser.) Erythema is the medical term for redness of the skin due to congestion of the capillaries. Frequency Doubling is a phase-sensitive process where an input (pump) wave (usually a laser beam) can generate a wave with twice the optical frequency in the medium with a similar direction. [http://www.rp-photonics.com/frequency_doubling.html source] Hurter-Driffield curve is a graphical curve formed by plotting the film density (log of opacity) versus the log of exposure time. Sometimes goes by other names such as characteristic curves, D–logE curves, and D–logH curves. Infrared radiation (IR) is electromagnetic radiation with wavelengths that lie within the range 0.7 mm to 1 mm. Intrabeam viewing is the viewing condition in which the source subtends an angle at the eye which is equal to or less than amin, the limiting angular subtense. In simpler terms, the eye views or is exposed to a laser beam directly. This category includes most collimated beams and so-called point sources. The iris is the circular pigmented membrane that lies behind the cornea of the human eye. The iris is perforated by the pupil. A joule (J) is a unit of energy (1 joule = 1 watt per second). A laser is a device that produces an intense, coherent, directional beam of light by stimulating electronic or molecular transitions to lower energy levels. Laser is an acronym for light amplification by stimulated emission of radiation. A macula is the small, uniquely pigmented and specialized area of the retina. Maximum permissible exposure (MPE) is the level of laser radiation to which a person may be exposed without hazardous effect on or adverse biological changes in the eye or skin. The ocular fundus is the back of the eye. The ocular fundus may be seen through the pupil by use of an ophthalmoscope. Optical density (Dl) is the logarithm to the base ten of the reciprocal of the transmittance: OD = log10(Ei/Et), where OD = optical density, Ei = incident beam irradiance (W/cm2) worst case exposure, and Et = transmitted beam irradiance (MPE limit in W/cm2). Power is the rate at which energy is emitted, transferred, or received. Protective housing is an enclosure that surrounds a laser or laser system, preventing access to laser radiation above the applicable MPE level. Pulse duration is the duration of a laser pulse, usually measured as the time interval between the half-power points on the leading and trailing edges of the pulse. A pulsed laser is a laser that delivers its energy in the form of a single pulse or train of pulses. A Q-switch is a device that produces very short (~10–250 ns), intense laser pulses by enhancing the storage and dumping of electronic energy in and out of the lasing medium. A Q-switched laser is a laser that emits short (~10–250 ns), high-power pulses by means of a Q-switch. Radiance is radiant flux or power output per unit solid angle per unit area. Reflection is the deviation of radiation following incidence on a surface. The retina is the sensory membrane that receives the incident image formed by the cornea and lens of the human eye. The retina lines the inside of the eye. Second-Harmonic Generation - See frequency doubling. A spectator is an individual who wishes to observe or watch a laser or laser system in operation and who may lack the appropriate laser safety training. Specular reflection is a mirrorlike reflection. Ultraviolet radiation (UV) is electromagnetic radiation with wavelengths smaller than those of visible radiation. A viewing portal is an opening in an experimental system, allowing the user to observe the experimental chamber. All viewing portals and display screens included as an integral part of a laser system must incorporate a suitable means to maintain the laser radiation at the viewing position at or below the applicable MPE (eye safe) for all conditions of operation and maintenance. It is essential that the material used for viewing portals and display screens not support combustion or release toxic vapors following exposure to laser radiation. Visible radiation (light) is electromagnetic radiation that can be detected by the human eye. This term is commonly used to describe wavelengths which lie in the range 0.4 to 0.7 mm. A watt (W) is the unit of power or radiant flux (1 watt = 1 joule per second). A wavelength is the distance between two successive points on a periodic wave which have the same phase. d5e54659f41c9ff4ca0b756d25ab9f307d2bae8f 0 168 183 2007-05-06T08:01:11Z Michael Harrison 0 wikitext text/x-wiki [[Sneaky Fish]] by Jeff Blyth dca874f2dad612d5707d3961b50d354bbb8721ba 0 510 1170 2007-05-06T08:02:55Z Michael Harrison 0 wikitext text/x-wiki When Applied Holographics were in full swing with that holocopier I remember sitting in the office of the leading light behind that enterprise,Hamish Shearer. We were both eying his nice goldfish in their aquarium when I had an idea. “Why don’t we make a pulsed portrait of them ?” I asked. We duly got a large 5 litre glass beaker filled it with water and Hamish carefully caught 2 of the smaller fish and we took it over to a spare ruby pulsed laser unit in a room there. There was no safelight in that room if I remember rightly but I think we got enough light in to set up the experiment with an AGFA 8E75 plate by leaving the door slightly open. I simply rested the plate ( I think it may have been a rather expensive 10 x 8” ) against the beaker to shoot a simple Denisyuk in a single spread beam pulse of Ruby 694nm. However for obvious health and safety reasons before we donned our goggles ready to shoot we had to lock the door , and this meant shooting the fish in pitch black darkness. I then put the exposed plate in a box and took it over to the lab to process. Then as we both eagerly watched the finished plate under a spot light as it dried under a hot hairdryer we saw…………….. NOTHING! or almost nothing except for a bit of the brand name PYREX. Not the slightest hint of a fish. We then repeated the operation with another ($50?) plate. The result was again no sign of a fish! I was utterly perplexed….and pretty embarrassed and annoyed, I was there as a supposed expert on making and processing Denisyuks , How could this be happening ? The fish couldn't possibly be moving too fast for a 20ns pulse and in any case they would have made a shadowgram on the piece of white card we put behind the beaker for the second shoot. Then we did some testing by turning the room lights on and off. The truth then was revealed .. ......... The moment the room went black those clever little bastards dived down and laid flat down on the bottom of the beaker!! ----obviously some sort of evolved survival mechanism to protect themselves from powerful alien laser beams presumably. We did on the third go finally manage to get our pulsed portrait of the fish but unfortunately…. it HAD to include an unedifying view of a Hamish arm as his hand had to rest on the bottom continually tickling the fish to keep them up in the picture frame. 6026a01e3fcc13905662cce2c97e6f14fbe1136f 0 249 345 2007-05-14T18:52:54Z Greg Quinn 0 wikitext text/x-wiki Greg Quinn worked at the National Physical Laboratory between January 21st 1974 and September 15th 1985 in the holographic interferometry group (at that time, part of the Department of Mechanical and Optical Metrology). Working under Tony Ennos, Eddie Archbold and finally Dave Williams, he created many display holograms that have been presented both internally and at national meetings since then. Following his time at NPL, he studied biochemistry at Leeds, and gained his Ph.D. in molecular biology at Southampton University. Greg is currently principal investigator of the Mobile Data Visualization Lab at the San Diego Supercomputer Center, at the University of California San Diego. He's married with one son. f5d97ab7d33526c080a4581898ad13cf2f92a773 6 295 483 2007-05-25T13:41:02Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 296 485 2007-05-25T13:43:19Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 306 567 2007-05-25T13:43:35Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 545 1240 2007-05-25T13:48:47Z John Pecora 0 wikitext text/x-wiki Thank you Colin for the formatting. I have a few images that I would like to upload but cannot. Here is the error I am getting;" The upload directory (/var/www/vhosts/holographyforum.org/httpdocs/HoloWiki/images) is not writable by the webserver." The images are in the reference (16). The first three images. The first two I would like in the collagen section. And the third in the Gelatin section. I wonder if you could upload the images or possibly investigate why I cannot upload the files. Thank you, John ---- Try that. Colin. ---- Thank you, works fine now! a638bd1dcd7da65082f784cbeb941653051198d6 0 195 237 2007-07-16T02:16:47Z Gregg Favalora 0 Added "instructables" and paper-reference links for CD-ROM holograms wikitext text/x-wiki The basic mathematics of computer generated holography are well understood. The major difficulties are in two areas - computer resources and output media. *As we increase the angle between the computed reference beam and the computed object beam, the fringe spacing becomes smaller and so the data set becomes very large. This requires vast amounts of data storage and computation time. Much work has gone into algorithms to simplify the calculations, but producing high quality imagery is still a difficult problem. *As the fringe spacing decreases, we require higher and higher resolution printout to a transparency. Electron beam lithography is one method used for very high resolution output, but the equipment is extremely expensive and is typically only designed for small imaging areas. These problems have made it so that only On-Axis (Gabor) Holograms and Fresnel Holograms are commonly produced nowadays. ===Recording holograms on CD-ROMs=== One possible high resolution medium is the surface of a CDROM. This has been explored and even used in such disks as Microsoft Windows Installation Disks. The software required to write this kind of dataset requires bypassing the driver software as the driver software limits the types of data possible. Also, there is no easy way to align successive tracks on a CD ROM. Some of the new CD ROM drives are capable of writing images to the front surface and may prove to be more suitable to hack into. There was a presentation at SPIE / IS&T Electronic Imaging 2004 (Practical Holography XVIII: Materials and Applications), which will be SPIE Proc. 5290: Computer-generated holograms on a CD-R disk, Y. Sakamoto, Hokkaido Univ. (Japan); M. Morishima, A. Usui, Yamaha Corp. (Japan) [5290-02] [http://adsabs.harvard.edu/abs/2004SPIE.5290...42S journal article info page] Colin Kaminski contacted Y. Sakamoto and was told that this project was abandoned by the manufacturer and this code was no longer available. [http://www.medcosm.com/prog_CGHmaker.htm MedCosm Computer Generated Holograms] [http://www.instructables.com/id/EKXB9DF5V7EP286HE7/?comments=all "Instructables" do-it-yourself page] ===Binary Detour=== 9294c8150571a03ebac6f52b94f0ac2918f8bb19 0 420 990 2007-07-22T01:58:20Z Colin Kaminski 0 wikitext text/x-wiki [[Image:PeacockZsm.jpg]] Peacock Feather made Using the Lippmann Process at the Optical Structure Laboratory at the Rowland Institute at Harvard. Lippmann photography is a way of making a color photograph that relies on Bragg reflection planes in the emulsion to make the colors. It is similar to using the colors of soap bubbles to make an image. [http://chem.ch.huji.ac.il/~eugeniik/history/lippmann.html Gabriel Jonas Lippmann] won the Nobel Prize in physics in 1908 for the creation of the first color photographic process. A conceptual method would be to use a color holography film like Slavich PFG-03 and [[Index Matching|index match]] a first surface mirror to the emulsion side. (Lippmann used mercury for the mirror.) Expose the film with a pinhole camera. Remove the mirror. Develop the film to avoid shrinkage with something like [[Silver_Halide_Processing_Chemistries#JD-4|JD-4]]. When illuminated by a diffuse source a color photograph is visible. Lippmann is an excelent choice for making security documents as explained in this paper by Hanz Bjelkhagen on [[Lippmann Security]]. Viewing a Lippmann photograph, a regular photograph and a hologram are quite different. Here is a page on [[Viewing Lippmann Photographs]]. '''[[Lippmann Papers|Papers on Lippmann Photography.]]''' '''Links''' *[[Gabriel Lippmann|Gabriel Lippmann's Biography]] *[http://nobelprize.org/physics/articles/biedermann/ Lippmann Photography vs Holography] *[http://www.pinhole.cz/ Pin Hole Camera Theory and Design] *[http://www.designerinlight.com/lippmann/ Lippmann pdfs (mostly in French)] *[http://holographyforum.org/phpBB2/viewforum.php?f=14 Lippmann Forum] *[http://en.wikipedia.org/wiki/Bragg_diffraction Bragg Diffraction from Wikipedia] 6abf7f41bf6e657368b6b7da38e27ff3f19924f6 0 392 935 2007-07-23T18:28:00Z Colin Kaminski 0 wikitext text/x-wiki ==Mounting Holographic Film== When choosing a index matching fluid it is important to have it be safe to handle, it can not evaporate to quickly, it must clean up without destroying the un-developed gelatin and it's [[Refractive Index]] should be glose to in-between glass and gelatin. That may be true for a great many “special applications” but probably not for the recording of display holograms. In the 80s, when we started working with Agfa's 8E75 material (back then coated on Melinex polyester film), we routinely used plain tap water for “index matching”. Though the refractive index of water hugely differs from that of Melinex (that's to say from 1.33 to roughly 1.64 or so), the mismatch did not show up in the final holographic image. Actually, it could only be detected if the film was examined in a transmission mode. It turns out the main issue here is keeping the film stable on a glass plate during exposure. Whereas polyester was very forgiving in that respect, handling nowadays' triacetate has become a lot trickier. If you are using film instead of glass plates then a method to hold the film stable is very important. The usual method with the AGFA materials is to use an index matching fluid to hold the film emulsion side out to a oversize glass plate. The simplest index matching fluid to use is liquid paraffin. This is sold as lamp oil. Make sure to get the oderless and smokeless variety as it is much more pure. The index of refraction is a little low but it works fairly well. Make sure to wash it off before you develop it. Use a drop or two of dish soap in 1/2 gallon of distilled water as a rinse before development. I would like to add that other liquids might be equally worth a try. E.g. white spirit and the like: paint thinner, paint cleaners etc. (provided they are low toxic of course). As I have just discovered there is also an ''odourless white spirit artist's quality'', made by Talens. Cedar oil might be another option. Compared to paraffin those liquids have the advantage of being removed quickly from the film – simply by warm air. It is very important to use the right amount of index matching fluid. Use an eye dropper to measure the fluid onto the plate. A syringe would be useful for larger plates. If you have air bubbles they will show up as blank portions of the holograms because the film will move. If you have too much then you have much to clean up before you can use the sandwich. If you get index matching fluid on the wrong side of the plate it is very difficult to clean it off under the safelight. Before using the sandwich check it in both transmitted safelight and reflected safelight to check for bubbles or smears. The AGFA materials and now the Fuji materials have a gelatin coating on both sides! This makes using the single plate method very easy. If you are using the Slavich materials they will often curl up on you. This has been attributed to the thinner triacitate base stock but it is likely it is the lack of a second gelatin coating. For the Slavich materials sandwich the film in between two glass plates. This can be done with index matching fluid. Slight correction regarding Agfa. Yes, they did a couple of film batches with gelatin coated on both sides. But that has been rather an exception. Speculating about the reason for the superiority of Agfa's materials (with respect to ease of handling prior to exposure only!), one might consider the particular triacetate film produced by Bayer or, a special subbing layer, used by Agfa or, the whole thing relates to the topcoat. Personally, I do not think it was just a matter of film thickness. If memory serves, Ilford materials (SP-673, HOTEC) used to have a similar film thickness. And yet, index matching those films on a glass plate became pretty challenging. Slavich (PFG-01 and PFG-03), Red Star, Ultimate and Filmotec all were similarly difficult to handle. Beside making index matched glass-film-glass sandwiches, glass-film-plastic sheet sandwiches seemed to work reasonably well. E.g. we would pour some index matching liquid on the middle of the glass plate and then apply the holographic film (emulsions side towards the liquid) to the glass. On top of the holographic film (base side) by means of some additional index matching liquid a plastic sheet (PMMA, PC etc. plate or some OHP film etc.) was applied. In those cases, adding a surfactant (Triton-100) to the index matching liquid used make life easier. ==Dry Film Mounting== Frank DeFreitas has an interesting mounting method. Here is some information from a post he made to his forum (now retired forum) at [http://www.holoworld.com holoworld]. It also has some very good information about finding the Brewster's angle. Frank DeFreitas - Mon, May 28, 01 10:51:49 PM When running test after test working with diodes in the now "early" days, I had to come up with a way of not going broke using glass plates -- while also keeping the quality of the holograms intact and consistent -- so that any problems would be from the laser test itself, and not the set-up. Of course, this meant working with film (AGFA-8E75HD at the time). With both time constraints and the shear number of test shots, I quickly became aware that wet-mounting was just too much to do each time. So here's what I did: Since the very nature of holography requires that glass plates be manufactured to exacting specs in regards to flatness, I took two old plates and placed them in a standard Clorox bleach solution. Within several minutes, the emulsion turns to a white paste and can be rinsed off with water -- leaving just the glass substrate. This took care of the problem with commercial glass and it's inconsistent "flatness" for sandwiching. NOTE: Since this IS a chemical reaction taking place, when removing the emulsion with bleach, use a fume-hood or do this outdoors. Once rinsed, clean the glass off with any standard window cleaner and take care to store them so they do not become scratched. Any scratch will show up in the final hologram -- and, if it is deep enough, actually create a shadow -- due to the angled surface of the physical scratch itself. Then, just take your film and sandwich it between the two pieces of glass. My method was to "squeeze" the glass together with a twisting motion while applying downward pressure. If done properly, you will create your own vacuum and the entire sandwich will stay together as one unit. When you REALLY get the hang of it, you'll find it hard to get it apart! Now, for the set-up: You will need a polarized laser and make sure that the polarization is properly oriented to your plateholder. You will also need to bring your reference beam (or single beam) in at "exactly" brewsters angle. One way to determine this is to set up your plateholder at brewsters and place a single piece of glass in it. Hit the glass with your spread beam. The glass is going to reflect some of the light hitting it, so place a white card in this reflected light path (in order to view it). If you rotate your laser head, you will notice that this reflected light becomes brighter and dimmer. Find the spot within the rotation where the reflected light is at it's dimmest on your white card, and you've got it. There should be two spots for this with every 360-degree of rotation. With my HeNe, it is at the 3:00 and 9:00 position(s) for side-reference (parallel to table). With the diode, it is at 12:00 and 6:00. With a HeNe, you'll always have a "little" bit of light reflected. With a properly-running diode, the reflection will go completely out on the card (100% -- or VERY close to 100% -- transmission through the glass). For side referencing, also make sure that your plateholder is not angled toward or away from the incoming laser light, too. It should be straight up and down in relation to the reference beam. This also means making sure that your incoming laser light stays parallel to the surface of the table . . . and is not directed upwards or downwards in any way toward the plateholder during it's travel. If you're using an overhead reference, then it should not be angled in any way from either SIDE. In other words, the ONLY "angle" present should be the reference angle -- no matter what table geometry or set-up you're using. Place your sandwich into the plateholder and give it time to "settle". It will take much longer with film than with a glass plate. I usually use this time to get chemistry ready, or go upstairs and have a cup of tea and relax, etc. Do your exposure as you normally would. If you have everything set-up properly as stated above, you will have a film hologram that is every bit as clear, bright and clean as one on glass plates -- without the cost of plates and without any type of index matching fluid or the associated mess and/or extra time. In closing, I have heard that the .mil thickness of the new film out there is less than it was previously with AGFA . . . so this may require a few "tweaks" here-and-there with settling time, etc. Regards, Frank ==Links== Micheal Harrison has a great article [http://www.dragonseye.com/blog/archives/15-Laminating-film-to-glass.html here!] 29cb3150832280aef117527dfda3e830248b42a3 0 589 1328 2007-07-26T16:00:01Z Colin Kaminski 0 wikitext text/x-wiki Most Lippmann photographs in museums are covered with a prism to bounce the first surface reflection from the eye. They are also painted black from the back to increase contrast. '''Darran Green writes:''' For daylight viewing select a room with one window through which an unobstructed region of sky can be seen. A hazy white sky or diffuse cloud is preferable to blue, but if blue select the brightest region for illuminating the plate. Stand the plate on a table or shelf, or just hold it at arms length, lower the cover glass to reveal the emulsion side of the plate,and arrange the emulsion side facing the sky and around two meters from the window. Once you see the sky mirrored in the plate you should also see any diffracted colours reconstructed from the image. It isn't absolutely necessary, but you can block out some of the light to reduce effective size of window and improve viewing conditions, as recommended by Ives, an early Lippmann photographer. For viewing by artificial light, black out a room, and use a diffuser such as a 8x10 transparency sleeve mounted in black card matt, arranged about 18" above the plate and a bright halogen spot above the diffuser. Arrange the plate emulsion side up with cover glass lowered, and when you see the diffuser mirrored in the plate the colours should appear. Another thing you could try for a bit of fun, is to find a room in which direct sunlight shines. Allow full sunlight to illuminate emulsion side with cover glass lowered. Using an opaque white card reflect the image onto the card at as close a range as possible without obstructing the projected image and to maintain image sharpness. The image will be laterally reversed. 344e13c5eb254372568bcd839b8656ca6cc8b5a5 6 351 787 2007-08-09T18:20:24Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 340 681 2007-08-09T18:52:13Z John Pecora 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 364 843 2007-10-06T04:58:02Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 365 845 2007-10-06T04:58:33Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 366 847 2007-10-06T04:59:06Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 367 849 2007-10-06T04:59:32Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 368 851 2007-10-06T04:59:57Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 369 853 2007-10-06T05:00:23Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 161 169 2007-10-07T16:54:07Z Colin Kaminski 0 wikitext text/x-wiki First of all great thanks to Bill Jensen – without his works on SSY1 I wouldn’t catch pulsed laser bug. Thanks Bill  Here is some information about my homebuilt pulsed laser. I named it YAGna (polish girl’s name, if you visit Poland most of our highlander’s daughters will be Jagna ). YAGna uses SSY1 Nd:YAG laser capable of giving 170mJ; 4ns; 1064nm pulses. It wasn’t built for taking portraits – rather for shooting small objects (insects, splashes, falling drops of quicksilver or Ga-In alloy). Right now I’m running SSY1 just above lasing threshold (2*230V*sqrt(2) = 644V at main cap, which gives something like 6,7J of energy). For two reasons – I’m still using original polymer q-switch which is delicate, at this power level both flashlamp and KTP will last forever. And at lower energy levels beam quality is better (I hope there is less unwanted longitudinal modes). At 6,5 J I get up to 38mJ of IR, after conversion and filtering unconverted IR (a filter from a dead VHS camcorder) I have 8-15mJ of 532nm light. YAGna is equipped with Brewster window to increase conversion efficiency. Conversion efficiency is low since KTP is not working near its destruction limit. It is better for the crystal. [[image:SSY1a.jpg]] YAGna standing on her 3 BLACK legs  Tika looking suspiciously at YAGna. Originally there was a rebreather inside the box (used in coal mines). [[image:SSY2.jpg]] Front side of the laser. A diverging lens, piezoelectric lighter on top (for firing flashlamp) and 3 wing-nuts for adjusting the tilt of KTP crystal. The case is sealed with black electrician’s tape (the tape is black, not the electrician ) to prevent the optics from dusting. [[Image:SSY3.jpg]] Inside YAGna. From left to right – KTP kinematic mount (rotation + tilt), pulse forming network, SSY1 laser on its breadboard, voltage doubler (based on 2 microwave oven HV capacitors and 2 HV diodes), 24V power supply (for PFN1s vacuum relay – after depowering the main capacitor is discharged) and an aligning laser (which ceased to work after 20-30 shots – maybe 0,1% of IR coming out from HR was sufficient to destroy the diode after focusing). As you cans see there is still plenty of room inside, so an amplifier stage, additional PFN1 and trigger board will fit. Case dimensions are something like 30x20x10cm. [[Image:SSY4.jpg]] Diverging lens, KTP mount, PFN1 network and SSY1 laser. The lens is slightly off-line to avoid backreflections (or rather because there were some problems with gluing ) [[Image:SSY5.jpg]] KTP mount. The crystal is glued inside brass block with thermoconductive glue. There is a 5mm tungsten iris in front of 5x5x5mm KTP crystal. [[Image:SSY6.jpg]] SSY1 Nd:YAG laser. Attached to a breadboard using magnets. [[Image:SSY7.jpg]] Beam shape after diverging. Photo was take before I mounted the tungsten iris. Since now I was shooting small (up to 4x3cm) test holograms (at 6,5J), but I got a holo showing entire face profile from Bill (taken at 15J). You can see some of my holos at YouTube: *http://youtube.com/watch?v=6U9ebkGEtl4 *http://youtube.com/watch?v=d4XoRhb9SOg *http://youtube.com/watch?v=LhR24W8M_aA Approximate cost of YAGna so far is around $400 (KTP acosted $250). I think minimalist’s version of YAGna (KTP salvaged from a dead DPSS pointer) could cost below $200. What I’d like to improve in YAGna: * add amplifier stage(s) – 2 SSY1s are already waiting to be used. * add spatial filter (1m focal length, 0,5mm DIY tungsten pinhole). * add trigger board and a laser photogate to make holograms of splashes. * divide YAGna in two – laser head and PSU on separate boxes. * make YAGna portable to make holograms outdoors. * whatever else imagination allows  1279f9614b1ae4b20e8500e87f0fff65e4186f33 6 300 533 2007-10-13T05:57:24Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 490 1130 2007-10-13T06:53:04Z Colin Kaminski 0 /* Scratch-O-Grams or Hand Drawn Holograms */ wikitext text/x-wiki ==Scratch-O-Grams or Hand Drawn Holograms== [[Image:Face2.gif]] Scratch-O-Gram by Raul. Scratch-O-Grams or Hand Drawn Holograms were first popularized by William J. Beaty in 1995. His article titled [[http://www.amasci.com/amateur/holo1.html Abrasion Holography]] is available on Science Hobbiest's website. A more technical paper by William J. Beaty was published by SPIE titled [[http://amasci.com/amateur/hand1.html Drawing Holograms by Hand]]. Tips for fabricating Scratch-O-Grams are [[http://amasci.com/amateur/holohint.html here.]] The definitive reference is: W. T. Plummer and L. R. Gardner, "A mechanically generated hologram", Applied Optics Vol.31, No. 31 (1 November 1992) pp.6585-6588. ==Computer Help for Designing Hand Drawn Holograms== Recently Holography Forum Member Raul provided a simple Visual Basic program for generating the scratch patterns from a 3D file. It currently works with small .3ds files or with .mcl files. .mcl files are created by a free program called MarbleCLAY and is available [http://homepage3.nifty.com/escargot/DownLoadFrm.html here]. Raul's program is called [http://www.holographyforum.org/files/3dS.zip 3dSilhouette]. The VB6 libraries are available [http://www.microsoft.com/downloads/details.aspx?familyid=7b9ba261-7a9c-43e7-9117-f673077ffb3c&displaylang=en Here]. He has a web site [http://3dalter.50megs.com/ here]. It generates a pattern showing the length and placement of the compass for making the scratches for complex objects. It can also break the object into pages of equal length lines to speed fabrication. ==Here are the instructions from Raul:== ''This is the program for making patterns. It is written in Visual Basic 6, and it needs some libraries. You need to download them or simply install VB6 on your PC. It works with .mcl, or.3ds input files. Mcl are marbleclay 3d files. Marbleclay can be freely downloaded from Internet, and is a very easy 3D editor.'' ''You need to create a folder c:\3dSilhouette and extract files into that folder.'' '''The software will not run at any other path.''' ''Patterns are printed in letter format sheets, files are located in the OUT folder. Several files may be generated, depending on object complexity.'' ''3d object can be rotated, moved and scaled. There is an option GetSilhouette that generates a wire frame model leaving only most important lines of the object for minimizing its complexity. You can then edit the object adding or erasing lines by simply double clicking on them.'' ''Set render options:'' ''XYScale –Vertical and Horizontal size of the object,'' ''Min Radius, Max Radius –They define object depth'' ''Left and Top margins – Is obvious.'' ''Line and scratch spacing define hologram density. Try to set a bigger number to reduce the number of patterns.'' ''Then you go to generate patterns, and render.'' ''With Line Patterns, scratches are drawn putting the compass centre on the bottom end of the lines and use line length as compass aperture. For horizontal lines, center compass in the right end. I use to make arc-shaped scratches with convexity looking to the top side of the sheet.'' '''One tip:''' ''If yow visualize the hologram in the way it appeared on the screen, image will go on deep. If you turn it upside down, image will pop in front of the sheet.'' '''Other tip (For Line Patterns)''' ''No matter that in even pages patterns appear horizontally all scratches are drawn the same way. In that cases you must center the compass in the right end of lines, and draw scratches in such a way that the tops of the arches aim to the top of the sheet. For vertical lines, it is more intuitive: center at the bottom and the top of arches matches with the top end with the lines.'' ''Equal depth pages option was implemented lately following a suggestion of Adam Libura.'' ''Program displays a page for each depth value (compass aperture) calculated. It is intended mostly for drawing on a transparency sheet laying directly on the lcd display screen. It displays a page of starting points for each compass aperture, which is shown in the left bottom corner of the page. You can use patterns right from Patterns window, or display bmp image files using windows image viewer. Pressing the button “Follow”, a cross pointer will navigate over the points to make it easier to find them correctly.'' '''One Suggestion:''' ''For drawing scratches in a transparency sheet, you can put the transparency on the sheet with pattern. Put compass tip on a piece of thick transparent plastic, to avoid damage the transparency. You can freely move the plastic piece on the transparency surface, to match the compass center with the bottom end of the lines. When lines are horizontal, center should be positioned at the right end of the lines.'' '''Another Suggestion:''' ''When viewing hologram, I backed it with a mirror, it help to increase brightness. I used to hang the hologram on the wall, at the height of the eyes, and illuminate it with a bright focus from a 3m distance. For viewing, I stayed 3m from the hologram, and focus hanged 20 cm over my head, in such a way that the focus slightly disappeared over the top border of the mirror.'' [http://www.youtube.com/watch?v=A40e2PgHPCQ U-tube Demonstration of a Scratch-O-Gram made by Raul] b9c568ea5d97299fca4d1280e0e3269a15f85f8a 0 193 233 2007-10-13T21:30:35Z Colin Kaminski 0 wikitext text/x-wiki [[Image:Colink.jpg]] Colin Kaminski is an amateur holographer who in a state of extreme frustration and needing advice started the forum that has become the [http://www.holographyforum.org Holography Forum] and now this Wiki. He really has no other holography releated acomplishments other than about 100 or so 4x5" and smaller holograms given to children. He has worked as an Assembly Language Programmer, Motorcycle Mechanic, Luthier, Theatrical Lighting Designer, Product Designer and now he is the Master Brewer at [http://www.downtownjoes.com Downtown Joe's] in Napa, CA. [http://www.designerinlight.com Colin Kaminski's Web Site] [[Image:Colinemail.gif]] b5f991a712c1fd534d9906ff0fc3b63ac38f6899 0 204 255 2007-11-02T14:07:51Z Colin Kaminski 0 /* Dichromated Gelatin - DCG */ wikitext text/x-wiki [[Dichromated Gelatin Chemistry]] ff3322ac04e57c17933b0a410293ac9a872e4c31 0 429 1008 2007-11-09T13:28:33Z John Pecora 0 wikitext text/x-wiki Choosing or making a model for a hologram is one of the most important tasks. ==Simple Guidelines== *Pick a reflective object. *Pick an object that is diffuse. *Pick an object you can hold still. *Pick an object that will not rock. ==Making Your Own Objects== There are many materials that work well for making your own objects. Any sculpting skills you have are well used in holography. ===Tips=== *Keep in mind that the object will be brighter if it is more reflective. *Diffuse objects randomize the polarization and can add to the fog level. *Highly reflective objects can cause local places on the film that overload the dynamic range of the recording. (Burn out) *Very bright spots need to be kept from the film plane when making H2 copies. ==Back Drops== You can laminate a transparency to a piece of glass and place it behind the scene and light it from behind. If you live near a large library there are old drawings and etchings in old books that have an expired copyright. These can be scanned and output onto a transparency. Once laminated to a piece of glass for stability, they can add interest to a scene. ==Lighting== Lighting holography objects is very similiar to lighting a photograph of the same object. Any good book on lighting for photography can be useful for holography. If you want hard shadows use the light straight from a spatial filter. If you want soft shadows or fill light pass an object beam through a diffuser. The size of the spot on the diffuser is a good judge of how diffuse the light will be. The main object beam will define all of the shadows present and is called the "Key Light" in photography. It can be straight from a spatial filter or it can be diffused slightly. Ground glass or opal glass can be sued for different effects. This light is often coming from in front, above and to the side of the object. From the other side a dimmer, more diffused light can be used. This is called the "Fill Light". This light serves to fill the shadows to reduce their contrast. Light can be brought from below and behind the object (remember that the film should not be able to see the light source directly) and is called "Back Light". Back light works well for objects that are transparent or have a fine structure that diffracts light well. Hair is a good example. ==Useful Materials== ===Sculpy=== ===Clay=== ===Plaster=== ===Epoxy Putty=== ==Painting your Model== In doing research I have found that Cadmium Yellow reflects 514 excellently while minimally reflecting 457. Cobalt Blue reflects excellently 457 while minimally reflecting 514. And Titanium White reflects both 514 and 457 equally as excellent. ==Links== [http://www.hirstarts.com/index.html Making Fantasy Architechure] 5d23131173da241b8f8ee9d3bfe0d1ce1d7c0d9a 0 243 333 2007-11-25T18:00:26Z Michael Harrison 0 wikitext text/x-wiki ==G307== (initial entry by John Pecora) This is Jeff Blyth’s formula for plates that exhibit an increased sensitivity to the green wavelengths 514 and 532. I have been exposing between 5 to 20mJ/cm^2 with very bright results. First it is necessary to coat plates with an emulsion of just gelatin and water using your preferred method (veil, bar, spin etc.) followed by curing of at least 12 hours. After curing the plates can be stored indefinitely, preferably in the refrigerator and just a few can be sensitized only when needed. ==Pre-exposure== To sensitize the plates, make up a solution as follows; Weigh out in order:- *0.5g glycerine *0.3g Aluminum Sulfate or Alum *100 ml distilled or de-ionized water *dissolve everything up then add: *5g potassium dichromate. Chill the solution to 5 degree C and then pour the solution into a container just larger then your glass plate. At this point a red safelight needs to be used and the standard yellow bug light for DCG will not work. Tilt the container to the side slightly, now take the glass and place it in the container, putting the edge in the deeper end of the liquid first and laying it down all in one motion while leveling the container. You will see the liquid slide across the top of the plate evenly. Only leave your plate in the solution for about half a minute then shake the plate free of droplets and wipe over the glass back with a paper towel. Stand the plates up against a wall at an angle and gently blow with a small desk fan or a hair dryer that has a cool setting until they are touch dry. At this point the alum in the formulation starts doing its job and is hardening up the coating a bit but it is only a gradual step and it is not instant. Now your plates should be used as you normally use them, needing to be shot at once or refrigerated for later use. AMENDMENT: '''Storage note about this solution''' If possible always try to use freshly made solution. However it can be stored in the dark in a fridge for a few days. The glycerine content will degrade rapidly if left in a bright light and slowly degrade in a dark reaction in the fridge. It may be possible to rejuvenate it with more glycerine but it is unlikely to be as good as the fresh stuff. ==Post exposure treatment== You need to have your oven at 100C (212F) and have a flat clean metal plate in it so that the metal instantly and evenly heats up your dry exposed plate. I have found that for a 4x5 plate 2 minutes is a good starting point. Depending on hardness of gelatin and exposure energy you may need to adjust this time. If the plates come out milky, increase the time. For the brightest hologram keep the baking time as low as possible without the plate coming out milky. After baking at 100C take the plate out and put it immediately onto a cold metal surface to rapidly and evenly cool the plate. Once the plate has cooled to room temperature, process with water and alcohol just as the standard DCG would be processed but use DI water in a container as the KDi will be lost into this water. When you are finished Sodium Metabisulfite can be added to change the CrVI to CrIII which is more environmentally friendly. You may need to leave the plate in the water rinse a bit longer to get all of the potassium dichromate out depending on the thickness of your emulsion. I use two baths, one for the majority of soaking to get most of the KDi out and the second as a quick final rinse. Once you have CrIII it will then be able to be precipitated out in a saturated solution of your sodium carbonate. An alternate drying method would be to just hit the plate with the hair dryer or other blower for just a few seconds to get the majority of alcohol off but then put the plate back into the oven at 100C until completely dry. ==Questions and Answers== ''' Q. What qualifies as "curing" for newly coated plates? 12 hours at any particular temp or humidity ? Well, the key is to have the gelatin cured enough to remain on the plate and not dissolve in the sensitizing bath. I would coat and leave in positive flow bench for 4 - 8 hours. At this point I would put the plain gelatin the fridge for later sensitizing and use. 12 hours is the minimum and as it is plain gelatin, storing for days or weeks is no problem. I believe 12 hours would be adequate for most environmental conditions. ''' Q. At what point does the sensitizer become light sensitive? Should the mixing be carried out under a safelight? Yes. Anytime you add KDi or AmDi to glycerine or gelatin you should use a safelight. ''' Q. What happens if one leaves the plate in solution more than 30 seconds? The only negative I can see is the gelatin will start to dissolve. ''' Q. Any chemists out there have any suggestions for a "preservative" to limit the glycerin dark reaction? Why do we want to limit it? It is the dark reaction additive that gives the G307 its increased sensitivity. ''' Q. Why is a cold plate used after post-exposure baking? This is used for larger (4x5" and up) plates so that the emulsion cools uniformly. Without this you may find that the brightness varies from the center to the outer edge of the plate due to differential cooling. Also, to cool the plate immediately such that the baking time can be more precisely controlled. The post baking is the additional hardening. If the plate was allowed to cool to room temp without a cold plate, obviously the hardening from the baking would be extended. Vary the room temperature and the control time is lost. ''' Q. What does this mean? "Once the plate has cooled to room temperature, process with water and alcohol just as the standard DCG would be processed but use DI water in a container as the KDi will be lost into this water." Soak the plate first to dissolve out the KDi? Yes, after the baking hardening there is still some unused KDi that will dissolve out. It is best to dissolve this out in a container such that it can be neutralized before disposing. ''' Q. "An alternate drying method. . ." Alternate to what? Alternate to the standard DCG method of drying which is with forced hot air after the last alcohol bath. ''' Q. What processing regime have people had good success with? Combinations of alcohol %, fixer, etc. DCG processing can be on [[A Beginners Approach to DCG]], [[MBDCG]] and [[The Mechanics of Gelatin and the DCG Process]]. It's unclear if or how the process might be changed for for G307. There is no fixer used in the G307. The G307 is different only up to the water rinse bath just prior to the alcohol dryings. All papers and techniques to change bandwidth or color from the water bath on, for standard processing, should apply. ''' Q. When using Sodium Metabisulfite to make the CrVI more environmentally friendly, how much should be used? How can one tell when one has added enough to change the CrVI to CrIII? CrVI is orangish in color. CRIII is bluish. When the solution has turned blue, that should be enough. A little more is better then not enough. I always add till blue and then some extra. Sodium Metabisilite is inexpensive. Unless you know exactly how much KDi is in the solution, I am not sure an exact measurement of Sodium Metabisulfite can be found. I wonder if there is a test to check if there is any CrVI left in the solution...??? ff7d3571d6e62bf34fd3101cac17178ee943aeb0 1 526 1202 2007-11-25T18:01:10Z Michael Harrison 0 wikitext text/x-wiki Moved un-answered questions here for further discussion. ''' Q. In this thread there was some discussion about using Sodium Dichromate instead of Potassium Dichromate and increasing the amounts of that and Glycerine to increase photosensitivity. Has anyone had good results with this? http://www.holographyforum.org/phpBB2/viewtopic.php?p=39965 ''' Q. What have people done about condensation on the cold plate? Keep it in a container with dessicant while it's not being used? ''' Q. Any chemists out there have any suggestions for a "preservative" to limit the glycerin dark reaction? ''Why do we want to limit it? It is the dark reaction additive that gives the G307 its increased sensitivity.'' Because it limits the storage time of prepared plates. If we could stop this reaction until it's desired, more plates could be made ahead of time, which would result in having more available of a known quality. d5888601fd4b974d9d58aee0275b1114015456e9 0 159 165 2007-12-05T16:28:18Z Colin Kaminski 0 wikitext text/x-wiki ==Here's my two cents:== From Joe Farina: Mix dichromate, gelatin, and water using some kind of double-boiler method, and keep it under 60C. Coat plates using whatever method you prefer. Let them dry under a gentle air flow for 4 hours. Store your plates in the refrigerator (use lock & lock or some other kind of airtight container). Make as many plates as possible to enable lots of tests. Do not desiccate or do anything else to them. (By the way, use Knox gelatin from the grocery store.) Now, do tests at your lesiure. Just take your container out of the fridge, let it get up to room temperature, and take a plate out (or you can immediately take it out if you hit the surface of the gelatin hard with warm air from a hairdryer to prevent excess condensation). Expose Denisyuk style with 100mW at 532. (I would say 2.5" X 2.5" plates would be good.) Let them set in the dark for 5 minutes after exposure. Rinse under cold tap water for a minute until the yellowness goes away. Soak in room-temperature water for a minute. Soak in 91% for a minute with agitation (room-temperature). Soak in 99% for three minutes with agitation (room-temperature). Then dry with hot air. If there is milkiness, you will need to harden the gelatin more after the dark reaction. You can user fixer or a 100W light bulb 6 inches away (for varying time periods) to do this. I prefer the light bulb method. See how your plates age, and how they perform over time. Change variables to see different results (well, I don't need to tell you this, since you probably know better than I do about trial-and-error work in holography). Just use the same principles you use to get such good silver halide holograms. One last word: don't try to pre-plan things too much. Just use the simplest DCG technique possible (it is really very simple if you have blue or green light). Don't make it any more complex than it has to be. End of lecture. * With a C315M (532nm) at 100mw start with a 1 to 3 minute exposure and adjust by factors of two to find the right exposure range. ie. 45 seconds, 90 seconds, 180 seconds. dd7709ca9e3fac825651a47da027a4535eec0201 0 520 1190 2007-12-07T16:46:47Z Colin Kaminski 0 /* Notes */ formatting wikitext text/x-wiki ==TJ1 Developer== by Jeff Blyth '''Part A''' *6g Metol (4-methylaminophenol sulfate) *1 litre deionized water Dissolve up first then add:- 40g. Ascorbic acid (vitamin "C") '''Part B''' *100g sodium carbonate anhydrous *30g sodium hydroxide *1 litre deionized water. (This one should be labeled "very caustic" use rubber gloves and eye protection --guard against splashing at all.) Just use equal volumes of A and B with the "floating dish" method. (2 close-fitting plastic dishes are arranged so that one floats ontop of the other which contains the developer. The volume in the lower dish should be just enough to give a minimal air gap so that the uptake of oxygen is minimised and the top dish can be used as a rocker to agitate developer over a plate. Development time:- This developer is intended to react fast (to keep the silver grains spheroidal rather than filamentary, and to minimize damage to the gelatin in the strongly alkaline solution). So sufficient exposure level to give a development time of only 15-30 seconds should be aimed for . ==Notes== Developer's lifetime with the floating dish method can be days, depending on usage. A yellow or mild brown color means the developer is still good. When the developer is very dark brown or black it should be discarded. ==How this developer is thought to operate== ''The ascorbate ion with lots of alkalinity around (Na hydroxide /carbonate) is a powerful reducing agent that gets oxidized by light-damaged AgBr grains to "dehydro-ascorbate " and black or brown Ag metal grains are produced.But ascorbate ions with their negative charge are slowed from approaching the Ag+ ions in the lattice of the grain because each Ag+ is surrounded by a barrier of about 6 oppositely charged Br- ions. in the latticework, which is most often in the cubic form. (AgBr crystals can be structurally like the familiar cubic NaCl crystal , each Na+ being surrounded by 6 Cl- ions and each Cl- ion is surrounded by 6 Na+ ions ).The negative Br- ions in the lattice repel the easy access of the negative ascorbate- ions.. However “metol” is a reducing agent which is a sulfate salt and is therefore positively charged. These positive reducing ions can pass rapidly through the negative Br- lattice barricade and start reducing the Ag+ to uncharged silver metal and causing the Br- lattice ions to go into solution. But the ascorbate ions are slightly more powerful reducing agents than the metol ions so that causes newly oxidized metol ions to get returned to their original reduced form by the ascorbate ions. Therefore the metol acts as a catalyst for the ascorbate developer because it may be only momentarily oxidized.. Only when much of the ascorbate has got oxidized, do the metol ions really start to stay oxidized and oxidised metol is nearly black whereas oxidized ascorbate is merely yellow-brown. This has the useful bonus of causing the developer to get increasingly dark and this therefore acts as an indicator that it is becoming exhausted . When the developer is virtually black and opaque it means that most of the ascorbate has been oxidized and the solution should be discarded. ( Slight darkenening means the developer is OK still) . --- Another bonus about metol seems to be that it has an instant slight hardening action on soft gelatin as can be found from doing a fingernail scratch test on the notoriously soft Slavich PFG-03 emulsion after say 15 seconds immersion in “TJ1” developer made up with and without metol.'' 2cdb9145542c1d92f189d81ee9ab3881859f08aa 0 477 1104 2007-12-13T05:00:51Z Colin Kaminski 0 /* Bleaching with Rehalogenating Bleach */ wikitext text/x-wiki ==Bleaching with Rehalogenating Bleach== by Jeff Blyth A successful bleach for reflection Holograms comes from using: '''60KB Rehalogenating Bleach''' *40g Ethylenediaminetetraacetic acid iron (111) sodium salt [Aldrich cat. No. 35,961-0] *60g. potassium bromide & *70 ml acetic acid Dissolved up in 1 litre water (tap water is OK here). This bleach is particularly good after a developer such as [[TJ1_Developer]] is used. ===Theory=== So what happens with in this type of bleach used WITHOUT FIXING (i.e.without removing unexposed AgBr) in thiosulfate, is that the developed up silver gets re-oxidized to AgBr. But instead of returning you to square one and leaving you with a uniform coating and distribution of AgBr again just as it was before you exposed it, it is energetically more favorable for the re-made AgBr to move over to the adjacent dark fringe made up of virgin AgBr and grow onto that dark fringe using the virgin AgBr grains as seeding centers. That actually requires the bleach solution to have some AgBr solvation ability to enable this carry-over effect to occur. This effect occurs with the help of the relatively high concentration of potassium bromide present because it does raise the solubility of AgBr in the solution through the formation of complexes. Now the great thing about this carry-over effect is that it causes almost all the original Ag in the emulsion to build up the fringes whereas if you had had to use fix you would have removed about half of your original silver content in the thiosulfate solution. A revealing experiment is to take a newly developed plate that has been in a stop bath of ~5% acetic acid, rinse it and then place it upright in a beaker so that it is half covered in a fix solution such as 20% sodium thiosulfate. After giving it gentle agitation over about 4 -5 minutes avoiding splashing the unimmersed half it is then all given a vigorous rinse under tap water. Then the whole plate is immersed in the above bleach formula and given constant agitation. The first interesting thing that will be seen is that the fixed half will take longer to bleach the dark silver than the unfixed half . This is at first counter-intuitive since one would expect that initially removing the undeveloped AgBr in the fix would later have left the bleach plenty of spare room in the gelatin to react and oxidize the silver metal without being encumbered by lots of AgBr still present. The second point that will be noticed is that when the whole plate is bleached there will be considerable scatter on the fixed half compared to the unfixed half. The increased scatter in the fixed half also testifies to the truth of that carry-over mechanism. The scatter is a consequence of the carry-over effect being unable to operate because of the missing virgin AgBr. Therefore the newly formed AgBr builds up around the dissolving silver grains in solution before reaching a level where it becomes energetically favorable to precipitate out. The precipitate will be in larger grains and to some extent will occur in the dark fringe areas where the gelatin is supposed to be free of AgBr in order to give good fringe contrast with the new AgBr in the light fringes. The finished hologram if it had been recorded in red will now be shifted to the green, scattery, and less bright than the unfixed half. ===Bleaching Transmission Holograms=== The formulation above has been found to work pretty well also with transmission Holograms (Hs). The not-so-good thing about it though is that the original sensitizing dyes become chemically locked into AgBr grains making the emulsion very vulnerable to print out, i.e. darkening slowly in ambient lighting, particularly sunshine. The dyes can be chemically inactivated with a 2% potassium or ammonium dichromate bath-- it takes about a minute after you have used the Ferric EDTA bleach. ===A Good Bleach for Transmission Holograms, (can also be used to make reflection ones with a shorter replay wavelength)=== A better bleach for transmission holograms is to dissolve up 0.5 to1 gram of iodine crystals in about 200 ml alcohol (methanol or ethanol) and then about 200ml of water is added. However before putting the plate in, it is essential this time to use fix. This is because the bleach has no carry-over power. The fix bath can be 20% sodium thiosulfate and the plate given about 4 minutes in it with mild agitation. It is then given a thorough rinse under tap water to remove all traces of fix. After the bleach step the iodine stain can be removed in a 70% alcohol bath. A very good point about this bleach is that the dyes are released by the fix and easily removed in the alcoholic iodine solution. A comparison was made by cutting a developed and stopped (5% acetic acid) transmission H in half and then bleaching one half in the ferric-EDTA bleach and the other half after fixing was put in the iodine bleach. The iodine bleached half finished up producing a slightly higher diffraction efficiency. (This could be due to the carry-over effect being less efficient in the larger fringe spacing of transmission Hs compared to reflection Hs.) If you choose to use this bleach on say a '''reflection hologram''' made with a red laser then you can get a quite nice final yellow-green replay color because contraction occurs due to loss of the original virgin AgBr in the fix solution. (You also get a little bit of expansion due to AgI replacing AgBr.) It may then look brighter than a red one would have looked because of the eye's extra sensitivity to light-green even though some valuable AgBr diffracting material has been lost ===References=== P. Hariharan, C.M. Chidley; Rehalogenating Bleaches for photographic phase holograms 2: spatial frequency effects. Appl. Optics. 27 No.18, 3852 (1988) ) 5e0c98d115c38a2527d85fc56af04c73e5eca7d5 0 245 337 2007-12-16T16:21:24Z Colin Kaminski 0 wikitext text/x-wiki Gelatin Type A - Acid process used in production of product. Primarily pork skins. Type B - Alkaline process used in production of product. Primarily cattle hides. Type B (bovine) - Alkaline process used in production of product. Specifically cattle bone. According to one supplier, this type may contain small amounts of silver salts which could increase speed of Silver Halide films although it was unknown how much (if any) effect this might have. Bloom Stength - This is a standard measurement that determines hardness of gelatin after a specific period of time. The higher the Bloom number the harder the gelatin. For Dichromated Gelatin emulsions, High bloom and type B is best. Notes: *It is best to gradually add the gelatin to room temperature water, let it swell up, then heat the swelled mixture while stirring to dissolve. *Cooking with too high a temperature destroys the gelatin - use a double boiler and thermometer or similar arrangemnet. *Knox Unflavored Gelatin has been shown to work well for DCG Holography. *Gelatin solution can be stored in a refrigerator and repeatedly reheated and reused for a while, but eventually goes bad due to mold etc. *Increase concentration of gelatin in water for thicker emulsion. *Heat glass to be coated for thinner emulsion. *Lower temperature of emulsion during coating for thicker emulsion. ==Measuring the Hardness of Gelatin== It is possible to measure the hardness of gelatin according to an article by Oliva, Boj and Pardo (1983) # Weigh gelatin. # Soak the gelatin in distilled water at 18C of 15 minutes. # Weigh gelatin again. # The swelling factor is S=(W-W0)/W0%. Higher values of S denote softer gelatin. For reference use: * AGFA 8E75HD plates had a swelling factor of 25. (Very hard) * Kodak 649F plates had a swelling factor of 200. According to the authors of the article, this was why the Kodak plates were so much better for adaptation to DCG. *[[Properties of Gelatin]] by Bernard Cole - mirrored with permission 53add30423321eed32de5938b83d2a15e7236898 6 302 537 2007-12-25T01:47:01Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 301 535 2007-12-25T01:51:11Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 438 1026 2007-12-25T20:26:39Z Colin Kaminski 0 wikitext text/x-wiki =====Mode Hops ===== Besides [[Equipment#Longitudinal_Modes_and_Coherence_Length|coherence length]], another important property of a laser is its stability against <b>mode hops</b>. A mode hop (or jump) refers to a sudden change of the [[Equipment#Longitudinal_Modes_and_Coherence_Length|longitudinal mode spectrum]], which typically occurs when the currently lasing mode drops out of the laser medium gain profile (eg, due to thermal expansion of the laser cavity), so that suddenly another mode at a slightly different wavelength has higher gain and so will start to lase. Its effect on a hologram is a reduced coherence length, in some respect quite similar as if several [[Equipment#Longitudinal_Modes_and_Coherence_Length|longitudinal modes]] lase simultaneously. Indeed, whether several different longitudinal modes are present simultaneously or whether they just lase one after the other, doesn't matter much: in each case interference fringes are blurred, and the severity of this effect depends on the frequency (or wavelength) difference of the involved modes (for mode hops the blurring also depends on the fraction of the exposure time during which a given mode lases; obviously a very brief hop to another mode will not matter much. In the following, we will assume for simplicity that all involved modes contribute during the same amount of time). Therefore, mode hops are much more serious for lasers with a large mode spacing or short cavities, such as [[Types_of_Lasers#Diode_Lasers|diode lasers]]. For the latter, the mode spacing is like 100Ghz, so one single mode hop during exposure time will effectively cut down the coherence length to a few mm or less -- pretty much ruining any hologram by giving it a "sliced bread" appearance. On the other hand, for a single mode [[Types_of_Lasers#Argon_Ion_Lasers |argon laser]], a mode hop effectively reduces the coherence length to roughly the length of the resonator, which does not matter for most holographic applications. Therefore, preventing mode hops is crucial for diode and other lasers with short cavities; the most common and important method is to stabilize the temperature of the laser to a fraction of a degree. The situation turns out to be even more delicate for <b>extended cavity ("ECDL")</b> designs, where an external grating is used to extend the cavity length from a mm to a few centimeters; while such constructions can do very well for atomic spectroscopy, they appear not to be too useful for holography due to stringent requirements for temperature stabilization, and a delicate setup requiring spectrum analyzing tools; see the [http://argonholo.webhop.net/laser/ECDL.html investigations here]. Related issues are smooth <b>mode drift</b> (without hops) on one extreme side, and <b>chaotic mode competition</b> on the other. If the temperature of a laser diode is slowly changed by a small amount, the cavity length smoothly changes and so does the wavelength of a given longitudinal mode. Even if no hop to another one occurs, the mere wavelength shift can also effectively reduce the coherence length and therefore must be small enough (as a rough estimate, the temperature of a laser diode must be held constant to a hundredth or even to a thousandth of a degree Celsius, during exposure time. For a more detailed discussion, see [[Types_of_Lasers#Diode_Lasers|here]]). Now, if we go on and change the temperature even further, a discrete mode hop may occur where the wavelength suddenly jumps by a larger amount; this is what we have described above. However, much worse than this can happen: in the transition zone, two (or even more) longitudinal modes can compete in such a way as to yield a chaotically fluctuating spectrum. If a diode runs in such a regime, it is totally unsuitable for any holography use! Whether hops are simple or chaotic is hard to predict, and depends on the precise operating conditions of the laser diode. For an illuminating review, see [http://www.ilxlightwave.com/appnotes/mode_hopping_semiconductor_lasers.pdf here]. <b>Detecting mode hops:</b> Simplest is to look for AC noise in the output of a photodiode via an oscilloscope, or just listen to it by coupling the photodiode to an audio amplifier. This is quite instructive and gives some idea about the behavior of your favorite diode laser. Below is a picture of the AC output of a photodiode that shows first a transition through a chaotic regime, and subsequent simple mode hops (1sec/div horizontal scale, picture taken from [http://argonholo.webhop.net/laser/diodelasers.html here]): [[Image:LDmodejumps.jpg]] b3633a414531ea858fae32b69bffa736213c060c 6 297 491 2007-12-27T06:55:26Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 298 493 2007-12-27T06:56:07Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 495 1140 2008-01-05T19:44:32Z Colin Kaminski 0 /* Embossed Holography */ wikitext text/x-wiki ===[[Single Beam Reflection]]=== [[Single Beam Reflection|Click here]] for illustrations and explanations. No plateholder or card blockers. Just the basics. ===[[Single Beam Transmission]]=== [[Single Beam Transmission|Click here]] for illustrations and explanations. No plateholder or card blockers. Just the basics. ===Split beam reflection=== ===Split beam transmission=== [[Path Length Matching]] [[Tips for Pulsed Ruby Holograms]] ===[[H1 to H2]]=== The [[H1 to H2]] copy technique is commonly used for production and copying of commercial art holograms. Though the setup is more complex and difficult than a simple single beam arrangement, the result can be MUCH brighter than the original H1 because during the copying process one has complete control over the [[Beam Ratio]]. Commercially, the savings in time when making many copies from a master H1 make it indispensible. Here is a discussion on using [[Brewster's Discussion|Brewster's angle]] in [[H1 to H2]] setups. One fact, that if not taught, will be learned very quickly, is very evident in the final hologram and can waste a lot of time, energy and materials. That is, it is the pseudoscopic real image that is being made from the H1 onto the H2. Because this image is pseudoscopic an overhead reference beam used in creating the H2 will create a hologram that if displayed also with an ovehead display light will display a pseudoscopic image. I doubt this is what is desired. Thus it is important that in the copy set up the reference beam needs to enter the plate from the bottom and what is actually the back of the hologram if the display lighting is needs to come in from the top front. I tried to illustrate this in the image below and this is for a reflection H2 copy. [[Image:H2Geometry.JPG]] ===Rainbow holograms=== A Rainbow hologram is a white light viewable transmission hologram. The vertical parallax is sacrificed so that the hologram can be viewed in white light. Most Rainbow holograms are displayed with a silver backing so that even though they are transmission holograms, they can be viewed as a reflection hologram, that is, with the light behind you and over your shoulder. A rainbow hologram (H2 transmission) can be made from any transmission H1 hologram. The key is to restrict the image from the H1 down to a slit. There are a variety of ways to do this (briefly describe below in the “Embossed Holography” section) but the simplest, and one we will explain here, is to set your table geometry up as a standard transmission H1 to transmission H2. Then simply mask the full size H1 down to a slit approximately 1cm in width along the horizontal relative to the object. If you have a white card in where the H2 should be you will see as you mask down the H1 the image’s depths on the white card become more visible or more in focus. Then expose as needed. Then when viewed with white light as a transmission the hologram will have full horizontal parallax when you move you head side to side but as you move your head up and down the image will scroll through the colors of the rainbow, thus the name. If you take your credit card outside and look at it in the sunlight, you can easily observe these phenomena. ===Saxby bypass=== ===Multiple coherence volumes=== Click here [[Multiple Coherence Volumes]] ===Path Length Matching=== Click here [[Path Length Matching]] ===Stereograms=== Stereograms are also called Muliplexed holograms. The idea behind the proceedure is very straight forward but depending on the number of slits, the actual technique can very difficult or to say the least, time consuming to produce. The basic building block of this hologram is the master H1 hologram. The master hologram is made up of individual holographic slits, which usually are simple 2D objects. But like the frames of a movie, each slit has a slightly different perspective. If you want to really invision this, take a completed tranmission hologram of an object and cut the film into very narrow slits, about 3mm in width. Now illuminate each slit and project the image onto a white screen. Because of the narrowness of the slit you will notice in the illumination of one slit that the real image, when projected on a screen, has most of it's depth focused on the screen at one plane. This is similar to the slit technique in the Embossed Holography section below. To make the individual slits, simply set your geometry up to make a tranmisson hologram. Usually the object used is a tranmission LCD screen in which the "object" can be rotated via a computer for the subsiquent frames or slits. A diffusing screen is also placed against the LCD screen on the opposited side of the LCD screen with respect to the holographic plate. The idea is to diffuse the laser light before it goes through the LCD screen and finally on to the plate. This technique can also be applied to transparancies or negative photographic or movie film instead of and LCD screen. When the LCD screen has the first of a series of consecutive images on it, the holographic plate is masked at one end down to a few millimeters slit. The exposure is then made. Now the next image is advanced on the LCD screen and the slit mask is moved to the adjacent spot on the holographic plate and the second exposure is made. This is repeated for every "frame". After development in essence what you have is a holographic plate that has many slits side by side on it with the slits containing subsiquent views of an object or scene all from a slightly different but adjacent perspective. When this master is copied onto another holographic plate (H1 to H2 copy set up) all perpectives form at the same relative location in space at the H2 plate. Then when this plate is processed and viewed a 3d image can be seen because one eye sees one perspective and the other eye sees another perspective allowing the brain to create a 3d image of the object. This is truely a great technique for scaling down holograms of people or places to smaller sizes which can fit on 4x5 plates. Because the hologram is made from 2d images is is also possible to holograph what normally could not be holographed, as is something that cannot be brought into the lab. Frank DeFreitas has great and easy step by step intstructions to get you started in Stereogram Portraits on his web site. http://www.holoworld.com/holoportraits/index.html ===Embossed Holography=== [[Embossed Holograms]] f29afe09db7ccf33de0abfe0fb05c511b2d53e61 0 223 293 2008-01-05T19:45:16Z Colin Kaminski 0 wikitext text/x-wiki [[Image:B3logo.jpg]] 2D/3D Hologram directed by Colin Kaminski An embossed hologram is a rainbow transmission hologram with a mirror (aluminized layer) laminated to the back. Much like the traditional vinyl record printing process, the pattern is embossed by heat and pressure from a metal stamp onto a thermoplastic medium. There are many types of embossed holograms. '''2D Embossed Holograms''' are made from two dimensional artwork, usually a transparency. '''2D/3D Embossed Holograms''' are made from a stack of two dimensional artworks so each layer is a different distance from the film plane. '''3D Embossed Holograms''' are made from three dimensional models. '''Multiplexed Embossed Holograms''' are made from many pieces of artwork, often from a LCD screen. Once the original artwork is ready, a transmission master hologram (H1) is made, usually with Silver Halide holographic film or plates. The H1 is a slit hologram which will provide the geometry for a Rainbow copy. This Slit is then used to make a Rainbow transmission hologram (H2) into Photoresist. The H2 is processed with an etching solution so that the recorded fringes become a relief pattern of grooves on the hologram surface. The Resist is then silverized, which preserves the relief pattern while alowing the surface of the hologram to be electrically conductive. This silverized hologram is then placed in an electroforming tank and nickel plated, becoming a Mother Shim. The Mother Shim is peeled off, rejigged, placed back into an electroforming tank and another shim is grown on top of the Mother shim which becomes the Child shim. Many Child shims can be made from one Mother shim. The Child shim is placed in a Holographic Printer or embossing machine. Using heat and pressure the releif pattern on the shim is pressed against thermoplastic and the pattern is transferred to the plastic. shown at the top of the page. As many thousands of stampings can be made from one Child shim and quite a few Child shims can be made from one Mother shim, it is very possbile to make hundreds of thousands of embossed images from one Mother Shim. '''Security Holograms''' Because holograms are impossible to make without a giant laboratory and millions of dollars, they are often used for security purposes. You probably have one on the credit card in your wallet. Feel more secure? '''Making Embossed Holograms''' There are a number of steps required to make embossed holograms. Thus the costs are quite high for the first embossed hologram but as the processes allows 100's of thousands of hologram to be stamped in plastic, the costs per hologram gets reduced to pennies with the increase in the number of holograms wanted. First artwork needs to be made. This can be a 3D model, some 2D litho "pictures" or computer generated artwork. The artwork needs to be rather shallow in depth because the nature of the embossed process requires the hologram to be a surface relief hologram utilizing only the fringes on the surface of the hologram. A special kind of transmission master needs to be made from this artwork. It is called a slit master (H1) or rainbow transmission master hologram and can consist of more then one slit. For a final embossed rainbow hologram that has the foreground or object roll through the rainbow colors while the background rolls through different colors (shifted) at the same time, two slits can be made on the same plate separated by the color shift distance. Most of the time this H1 is made in silver halide. Once the transmission master (H1) is made a transmission copy (H2) is made from the H1 master. If there are two slits on the master they can both be imaged onto the H2 copy with one exposure. This is usually done on photoresist. Photoresist is most sensitive to the UV but is less sensitive to the deep blues and blue lines. The HeCd laser is most used for this exposure but the 457 line of and Argon Ion can be used. Exposure times of 30 or more minutes are not uncommon. Once the resist copy rainbow hologram is made, it is put in an etching solution that etches away the areas that have not been exposed to light (the destructive interference parts of the fringes) and leaves the exposed regions of the fringes (there are some etching solutions that work opposite and remove the exposed parts and leave the unexposed parts). The hologram can now be seen in on the resist. The resist is then covered with an electrically conductive layer, usually silver. A two part silverizing process used to make mirrors can be adapted to use for this process. It is important to maintain the surface relief structure of the fringes so a process that lays down an atom at a time is necessary. To simply coat the resist with silver would "level" out the fringes. The silverized hologram is then placed in an electroforming tank and a layer of nickel is deposited (grown) onto the silverized hologram. This is called the mother nickel shim. The mother nickel shim is then peeled away from the resist which degrades and destroys the resist which is no longer any good. The mother nickel shim is placed back in the electroforming tank and another layer of nickel is deposited onto the mother shim. This layer is then peeled off mother shim and is called the daughter shim. Many daughter shims can be made from a single mother shim by reintroducing the mother shim back into the electroforming tank and growing a subsequent daughter shim from it. The daughter shim is then placed into an embossing printer which "stamps" the relief fringes maintained in the shim onto the surface of a plastic film using heat and pressure. This printer can print out hundreds of hologram per minute. After thousands of holograms are stamped from a single daughter shim the daughter shim starts to degrade. The printer can then be loaded with another daughter shim and the process can continue. As the final hologram is a transmission hologram a reflective backing, usually Mylar, needs to be present such that the light can pass through the hologram, reflect off the backing and illuminate the embossed hologram from the back. The reflective backing can be part of the original stock plastic that passes through the printer or added during or after the embossing process. Also, other qualities like an adhesive backing can also be accommodated for with the stock plastic material. As you can see, it is quite elaborate to make the first embossed hologram but after thousands, the cost can be reduced 10,000 to 100,000 fold. It is not uncommon to see mass produced embossed holograms retail sell for $0.05 (US) a piece. fcfd998a2ccdc195a617315504c684a030087f41 0 570 1290 2008-01-05T19:51:45Z Colin Kaminski 0 /* Safe Light Types */ wikitext text/x-wiki ===Dust Hoods=== Keeping your work area dust free is a prime consideration when making your own emulsions. HEPA work stations are commercially available but are expensive. A home made work station can be easily made. [[Image:LaminarDetail.jpg]] John Peccora built this nice bench top Dust hood for DCG plate coating. On the left is the front view and on the right is a side cross section. For the back wall he used a plastic material that looks like square tubes with a screen covering. [[Image:CommercialLaminar.jpg]] This is a Commercial HEPA work station made by [http://www.nuaire.com/ NuAire]. It has pre-filters on the bottom with a squirel cage blower and the entire back of the work area is one large HEPA filter (4' x 3'). There are four 4' flourescent bulbs in the top. In order to make sure there are no air vortexes that can trap dust it is important to have the air flow over the entire bench in a laminar fasion. In order to insure a laminar flow the air needs to be directed through a parallel series of tubes. A bunch of straws work perfectly. In order to test the flow one can take a candle and put the flame in different places in the work area. Places where the flame flickers have turbulence and are unacceptable. ===Fume Extraction=== Processing with formaldehyde and alcohols are common in processing holograms. The fumes are dangerous and provisions should be made for venting them saftly outside. A simple bathroom fan is insufficient. Commercial suppliers like [http://www.mcmaster.com McMaster Carr] and [http://www.mscindustrial.com MSC Industrial] have explosion proof fan assemblies in the $500 range. A good rule of thumb is to have enough venting to exchange the complete air in your room 30 times per hour. Check your local regulations for more requirements. ===Processing Areas=== The processing are needs to be designed with a few considerations: *Light tight *Washable surfaces *Dust free *Running water *Lockable chemical storage *Counter space for processing trays ===Safe lights=== In order to see while you are working it is important to have some light. Fortunately if you are using film that is only sensitive to red you can make a green safelight. You should test your safelight before you use it. If you are using long settle times it is wise to make sure no safelight hits the bench during the settle period. ====Testing Safe Lights==== Do a preliminary test of reflecting the light off of a diffraction grating, CD or DVD. Shine the safe light at the grating and bounce the reflection back to your eyes. If it looks the same then you are looking at the zero order reflection, rotate the grating or CD until you see a reflection that looks like a rainbow. This is a higher order reflection. If you can see red in this reflection then your light is not safe. ====Exposure Test==== The next test is to get out a piece of your film. Find the uncoated side. Place a piece of electrical tape down one side to make a test patch that has not been exposed. Put the film about a foot from your safelight with the tape facing the light. Add one piece of tape at 15 seconds, 30 seconds, 60 seconds, 10 minutes, 30 minutes. At 60 minutes put the plate in developer. If your plate turns completely black then your safelight is not usable. If only the 60 minute or 30 minute lines develop you are probably OK. ====Safe Light Types==== '''For Red Sensitive Film''' *Lime Light: The easiest light to use is a "Limelight" night light. It is very low power and mostly green. If you add a Rosco Gel #90 available from a theatrical supply shop it will be very good but very low power. Attach the gel with electrical tape. John Klayer uses a row of gelled Limelights above his bench. *Kodak Safe Lights: Kodak makes a #7B and #3 green saflelight filters (#3 is recommended by Shoebox Holography) suitable for red sensitive holographic films. *Home Made Lights: Just using a piece of Rosco #90 (Theater Gel) over a conventional bulb is not enough. Use two layers of #90 or better to have one layer of #90 and one layer of #95. #95 lets in too much deep red to use alone and #90 lets in too much yellow that the Slavich materials are sensitive to. *MiniMag Flash Light: Use Two layers of Rosco #90 or better yet one layer of #90 and one of #95 for red sensitive film. *T40 EncapSulite fluorescent bulb covers can be used for holographic safelights. [http://www.flexopress.com/production/encapsulitelightsleeves.html EncapSulite] For general information about Safelights see: [http://www.kodak.com/global/en/consumer/products/techInfo/k4/k4Facts.shtml Kodak Safe Lights] 1e39ee67f2f384f525685676d7e63b86a502a8b7 0 437 1024 2008-01-05T19:57:00Z Colin Kaminski 0 wikitext text/x-wiki Flat mirrors are used in holography whenever the beam needs to be turned. For most holography there is no need for precision mirrors but it is very important the the mirror be [http://en.wikipedia.org/wiki/Optical_coating coated] with a reflection coating on the front side (Known as a "front surface" mirror). Small concave mirrors are available that can be used as a beam expander. [[Cleaning Mirrors]] ====Silvered Mirrors==== Silvered mirrors have the advantage that they are inexpensive but their damage threshold is usually low. Their reflectivity is only about 85-90% in non enhanced aluminum coatings. Silvered mirrors almost always have a protective overcoating and can also have an enhanced coating to increase the reflectivity to better than 90% in the visible range. Enhanced coatings are cost advantagous compared to buying a more powerful laser. ====Dielectric Mirrors==== Dielectric mirrors have the highest reflectivity and damage threshold available. They are more sensitive to reflection angle than silvered mirrors and are not often used at angles greater than 50 deg. Reflectivities can exceed 98%. They are created by coating the surface with coatings of alternating index of refraction at 1/2 wavelength thicknesses. The larger the difference in index of refraction and the more coatings, the higher efficiency the mirror will have. This is the mirror of choice inside of laser cavities because of their high efficiency. Damage threshold is about 100mj/cm^2. [[Cleaning Dielectric Mirrors]] ====Collimation Mirrors==== [[Image:CollimationMirror.jpg]] 10.1" f 4.5 parabolic mirror in a home made mount. Some holographers prefer collimation lenses rather than mirrors but the cost is lower for a mirror so many use a mirror. The ideal mirror is a spheroid figure. Telescopes have a paraboloid figure. Since there are many used telescope mirrors available many holographers choose to use them. Since a telescope suffers from the [[Optics Aberrations|aberration]] called coma it is best to keep the reflected angle as small as possible. =====Tips===== *A disposable shower cap makes a good cover for your collimation mirror when it is not in use. *For a collimated beam the pin hole of the spatial filter (or focal point of the expanding lens) needs to be the diameter times the focal ratio away from the mirror. For the mirror above 49.5 inches. =====Finding the Focal Point of a Collimator when f stop or focal point is unknown===== *If the f stop or the focal length of a collimator is not known, here is a way to find out where to place the pinhole to get a collimated beam. Measure the diameter of your collimator. Now draw a circle on a white piece of paper with that diameter. Place the paper about 2 or 3 meters (actually as far away as possible) away from the collimator such that the reflected raw laser beam bounces off the collimator and hits directly in the center of the circle on the paper. Now take your lens and place it in the beam prior to the collimator and close to it. Keep an eye on the spot being projected onto the paper with the circle drawn on it. Now start moving the lens away from the collimator, up stream of the laser beam while watching the spot on the paper. As you move back the beam will get bigger and bigger until there is a point where it remains the same size. Mark the distance the lens focal point is from the collimator. Now continue back until the spot becomes smaller. Mark this distance. The focal point of the collimator will be approximately in the center of these two marks. *For a final adjustment, place the lens focal point at the found focal point. Take the white paper with the circle on it and move it toward the collimator. If the spot becomes smaller the beam is diverging and the lens needs to be moved further away from the collimator. If the spot becomes larger when moving toward the collimator the beam is converging and the lens needs to be moved closer to the collimator. Repeat this procedure until the spot remains the exact same size while moving from that very far away point all the way up to very close to the collimator. When you find the focal length (which is from the focal point of the lens to the center of the collimator, write it down directly on the back or side of the collimator for future reference thus needing to do this procedure once for that mirror. *It is best to use a low power lens that allows this procedure to be carried out such that the beam is never expanded past the edge of the collimator. If, while moving the lens away from the collimator the beam expands past the edges of the collimator and the reflected spot has not yet stopped expanding, stop at this point and note the size of the reflected spot on the paper. It should be the same size or larger then the drawn circle (it is impossible that the reflected spot is smaller or the reflected spot would have already stopped expanding and would have started getting smaller). If the spot size is the same size of the circle you are at the approximate focal length. If the spot is large then the drawn circle, continue moving the lens away from the collimator unit the spot is the same size as the drawn circle and this will be your approximate focal length. At this point perform the procedure for Final Adjustment above. ====Mirrors Used for Polarization Rotation==== This image is self explanitory on how to rotate the polarization of the laser beam with two front surface steerable mirrors. This was taken directly from Kaveh's Thesis with his permission. [[Image:PolarizRotateWMirrors.jpg]] 5a43109e09e8a969d4dc16ca8dbf1b6bbc2cab8b 0 416 982 2008-01-05T19:58:24Z Colin Kaminski 0 wikitext text/x-wiki Lenses are very useful for holography. Small lenses can be used to expand the beam, to change the diameter of the beam and to change the height to width ratio of the beam. The best lenses are [http://en.wikipedia.org/wiki/Optical_coating Anti-Reflection] coated for the frequency of laser/s in use. Large lenses can be used to collimate a laser beam or to form a real image to make image planed holograms. [[Cleaning Lenses]] ====Choosing the Correct Lens==== '''From Tom B.''' Let beam diameter d be 4 mm and lens focal length f be 5 mm, The beam is brought to a focal point f mm past the lens, and in cross section looks like an isoceles triangle with the acute angle A at the focus. The half-angle hA of the right-triangle part of the cone is given by hA = arctan ((d/2)/f) = arctan (2/5) = arctan(0.4) = 21.8 degrees. Past the focus, the beam diverges at 2 * hA. For a given distance past focus L, the beam radius R is L * tan(hA), or L = R / tan(hA) For the given diameter D of 100 mm, R is 50 mm, and L = 50 mm / tan(21.8) = 50/0.4 = 125 mm So if we have an 8" collimation mirror, and we have a 4mm laser beam with no divergence and we want a colliated out beam then we would choose a lens with the focal length: working... ====Spherical==== This is the most common shape for a lens. It has one or both surfaces ground to a spherical surface. It can either be concave or convex. They suffer from spherical aberrations but this is not important in many applications. Plano-convex lenses have a positive focal length defined by f=R/(n-1) where R is the radius of curvature and n is the index of refraction of the glass used. Plano-concave lenses have a negative focal length defined by f=-R/(n-1). Bi-Convex lenses have a positive focal length defined by f=((2(n-1)/r)-(Tc(n-1)^2)/nR^2))^-1. Where Tc is the overall thickness of the lens. Bi-Concave lenses have a negative focal length defined by f=-((2(n-1)/r)-(Tc(n-1)^2)/nR^2))^-1. ====Cylindrical==== Cylindrical lenses are only ground on one axis. If placed into a laser beam they only expand one axis forming a line. With two lenses you can circularize an elliptical beam. If the ratio of the beam width to height is 3 to 1 then the focal lengths of the correcting lenses must be 3 to 1 (ie. 75mm and 25mm). The lenses are then placed at f1+f2 distance apart (ie. 100mm). Cylindrical lenses are also useful before the collimating optic in order to make a slit reference beam. Holographic stereograms and Rainbow Holograms are examples of where a cylindrical lens could be useful. ====Aspheric==== Aspheric lenses are ground to a special figure that corrects for [[Optics Aberrations|spherical aberrations]]. ====Objectives==== Microscope objectives are often used in spatial filters. They work best if AR coated to the wavelength of the laser in use. You can convert from focal length to magnification with the following formula: M = 250 / f or f = 250 / M where M is the magnification of the objective and f is the focal length of the lens. [http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=1922&search=1Edmund Industrial Optics] makes a laser line series of objectives that have very low losses at 632nm. ====GRIN Lenses==== Gradient Index Lenses have no figure cut into them. The focusing ability comes from changing the index of refraction across the surface of the lens. They are often used to focus light from a 808nm diode into the end of a YAG crystal for a DPSS laser. They are produced by silver-ion exchange (or lithium-ion exchange for low numerical apertures) in a special glass. GRIN lenses come in two basic flavors: RADIAL or AXIAL which are sometimes referred to as RGRIN and AGRIN respectively. RGRINS are usually used where you want to add optical power to focus light. An RGRIN with flat surfaces can focus light just as a normal lens with curved surfaces does. Thin RGRIN lenses with flat surfaces are known as WOOD lenses, named after the American physicist R.W. Wood who did a lot of experimental work with radial gradients from about 1895 to 1905 and included descriptions of how to make them in his physics text book (available from [http://www.osa.org/ OSA]). GRIN Math: The Eikonal equation (Born & Wolf) says that d(nk)/ds = gradient n where nk is the ray vector, s is the distance along the direction of propagation, and n is the refractive index. So moving to finite differentials gives delta(nk) = delta(s) * gradient n For Example, gradient n = (1.355 - 1.300) / 15 mm = 0.0037 per mm so delta(s) * gradient n = 5.5 mm * 0.0037 /mm = 0.0202 Now remember that nk is along the horizontal direction with a magnitude of 1.300 and delta(nk) is perpendicular to it, pointed toward the optical axis. Thus the vector sum of ray vector and change to the ray vector will have an angle of tangent (0.020/1.300) = 0.89 degrees in the glass In air, Snell's law says that this angle will increase to inverse sine(1.300*(sine(0.89 degrees)) = 1.15 degrees. So the ray exits at a height of about 15 mm with a slope of 1.15 degrees; this means it will strike the optical axis at a distance of 15 mm / tan(1.15 degrees), which is 747 mm. Which isn't the 409 mm you got f9a2945eef51846e379eabc6422fa01f77c159d4 0 177 201 2008-01-05T19:59:28Z Colin Kaminski 0 wikitext text/x-wiki Holography requires that two beams interfere at the plate. This is usually accomplished with a beam splitter. ====Reflective Beamsplitters==== A reflective beam splitter is a partially silvered mirror. It can be made so as to reflect a percentage of the light and transmit the rest. Common beam splitters come in 90/10, 70/30 and 50/50 splits. There are also variable beamsplitters. They consist of a partially silvered mirror that changes density from one place to another. The two types commonly available are linear and circular. The require a stable mount that will allow the ratio to be adjusted without changing the beam direction. Most commercially available beamsplitters are variable neutral density splitters. As such they are made on thin glass. It is common for hobbyists to laminate a piece of glass to the beam splitter to make it thicker. This separates the reflection from the back surface from the reflected beam in order to allow it to be blocked. Any index matching glue can be used. Norland makes a range of UV cured index matching adhesives that are suitable. When placing a reflective beamsplitter make sure to place the reflective side towards the laser. ====Cube Beamsplitters==== Cube beam splitters are used when higher damage thresholds are needed. They are more expensive but there is no problem with the ghost beam. Cube beamsplitters are available in Polarizing and Non-Polarizing varieties. A polarizing cube beamsplitter can be made variable by having 2 1/2 wave plates. One on the input beam and the other on the straight through beam. The input polarization is rotated to get the desired beam ratio and the output polarization is rotated to match the reflected polarization. Cube Beamsplitters are often AR coated. ====Pellicle Beamsplitters==== Pellicle Beam Splitters are not suitable for holography owing to the fact that their thickness (2um) makes it impossible to block the ghost beam from the back surface. 52459d85f79a6d8af9eb3635ae31f6ae2c249da9 0 498 1146 2008-01-05T20:10:37Z Colin Kaminski 0 wikitext text/x-wiki For recording holograms, some form of shutter is always necessary: switching on and off the laser instead is not feasible, as a laser will always take some time until it comes into thermal equilibrium, and before that there will be a lot of frequency drifts and [[Mode Hop]]s that will ruin the hologram. The settling time of a laser can be minutes up to one hour or so. The simplest method is to manually remove a black cardboard out of the beam path, but there is a great danger of induced vibrations on the holography table. This source of potential failure of a hologram is one of the easiest to exclude, by using an electronic shutter. Such a shutter can be used remotely controlled, or even fully automated if allows a programmable exposure time going off after some delay. This allows the holographer to be outside of the room during the shot, which is an important factor for cutting down disturbing vibrations and air currents. Using an electronically timed shutter is also convenient for achieving reproducible exposure times. There are mainly two ingredients: first, the actual shutter and then, the controller. The actual shutter is in most cases a mechanical device. If it is to be present on the same table as the holography setup, it is important to avoid any kind of vibrations. One method to build such a thing is to glue a small piece of mirror or aluminum foil to the needle of a mechanical voltmeter, and to drill a hole through the scale of the voltmeter to provide a path for the beam. The advantage is that the motion is very gentle and hardly induces any vibration. For higher power lasers, somewhat more massive shutters are better suitable, and these need to be mechanically isolated from the holography setup (eg by putting them on an extra table together with the laser). Often Ilex (now Melles Griot) electronic shutters are available as surplus for photographers. Another method to build fast-acting shutters from broken hard disks is described [http://optics.ph.unimelb.edu.au/atomopt/publications/shutter_rsi75_p3077_2004.pdf here]. Many shutter controllers made for photographic dark room use are suitable and are easily available on ebay. Just make sure that the programmable exposure time lies in the range that is useful for holography (ie, one second to one or several minutes depending on your setup). Having the possibility of an extra delay of 10 minutes or so before shooting allows a fully automated setup without direct user intervention. All this can conveniently be achieved also by a simple computer interface. 529c9b2be66ed9a6315ec4e7c7d59fc791360182 0 240 327 2008-01-05T20:11:36Z Colin Kaminski 0 wikitext text/x-wiki Fringe lockers can be used to diagnose problems with a set up. The output is sent to a scope to find out the frequency of the problem. They can also be used to correct very small instabilities with set ups. Depending on the movement capacity of the piezo element or piezo element stack, the fringe locker can compensate for movements from a few fringes up to 10's of fringes. The fringe locker used for corrections is most widely used for long exposures. The types of movement they can compensate for depends on the frequency response. They work on the principal that a fringe from the setup is expanded with a lens so that one fringe is in between two photodetectors. If the fringe starts to move a difference in voltage between the two photodetectors is noticed. This signal is sent to a piezo element under a mirror in one of the beam paths in order to change it's length and hold the fringe still. A commercial example is the [http://www.stabilock.com/ Stabilock]. A home made circuit from Joe looks like this: [[Image:Fringelock.gif]] b61529fe5a227226bf270b7308c46f650fb14b98 0 233 313 2008-01-05T20:13:27Z Colin Kaminski 0 wikitext text/x-wiki A Farady rotator is made from a non-linear material with an electric current passing either across the light path or along the light path in the crystal. They are used in [[Ring Laser|Ring Lasers]] and in [[Faraday Isolator|Faraday Isolators]]. A Faraday Rotator rotates light using the Faraday Effect. The degree of rotation is controled by an induced magnetic field. The two main uses for a Faraday Rotator are putting a polarizer in front so that back scatter is rotated and blocked by the polarizer and using them with wave plates to make a ring laser. [[Image:FaradayRotator.png]] The plane of linearly polarized light is rotated when a magnetic field is applied parallel to the propagation direction. The empirical angle of rotation is given by: [[Image:FaradayEQ.png]] *Where β is the angle of rotation (in radians). *B is the magnetic flux density in the direction of propagation (in teslas). *d is the length of the path (in metres) where the light and magnetic field interact. *Then V is the Verdet constant for the material. This empirical proportionality constant (in units of radians per tesla per metre, rad/(T·m)) varies with wavelength and temperature and is tabulated for various materials. 1d54e7ccb6e0a3d9444b94da4fbb3fe714bef7ce 0 448 1046 2008-01-05T20:15:41Z Colin Kaminski 0 wikitext text/x-wiki Stability is very important to holography. In order to hold the relative alignments of the optics the table must be stiff. It also must be isolated from vibrations coming from the ground and air. To learn about table design see [[Table Design Theory ]]. To see pictures of lab's set up for making holograms see a [[Tour of Holography Labs]]. ====Pavers==== Pavers make a great table if you only need to have a 1' x 1' table. There many setups that can be made on a small table. See [[Laser Pointer Holography]] for examples. ====Concrete Tables==== Concrete tables are inexpensive easy to fabricate and very stiff. This comes at the price of weight. The weight helps to isolate the table from vibrations coming from the ground. Many sucessful tables have been made 4'x8'x3.5" thick. ====Sand Tables==== Sand tables are the easiest to use, cheapest to make and most versatile tables available. They have made more holograms than any other home built table. When building a sand table it is important to use dust free sand. The kind sold for ash trays works well. Lon Moore's last table was 4x8' of 3.5" thick concrete with brick and mortor side walls enclosing sand 2' deep. It was extremely versatile and stable. Making optic mounts for a sand table is extremely quick and easy. Most people use PVC tubing fashioned with hand tools. ====Concrete Block Tables==== by Bob Hess I've described my 4x8' tables made of cinder blocks with steel plate and breadboard tops here in the past, floating on three or four inner tubes (from fork lift tires) or on tennis balls (an idea I got from Ken Haines). They all work fine if you can live with the excentricities of each type. I always rubbed the burrs off the cinder blocks before building the tables to decrease their stress when cinched together, and made the top of the blocks as flat as possible to minimize the thickness of filler material between them and the top. Lay a piece of plastic film between the filler material and the top so you don't stick the top to the blocks for easier disassembly. I never used hexcel because the skin is too thin to adequately support heavy loads locally (in my opinion). A 4x8' optical breadboard with the threaded holes is best for a top as it's 3/16" skin is locally rigid, the surface is flat, and it can be moved by two men with piano dollies. I like laying the cinder blocks out interlaced like a wall on its side, and running the threaded rods parallel to the short dimension of the table to minimize their length. [[Image:ConcreteBlock1.jpg]] I thought I'd post some pics of old tables I described earlier in this thread. The one on the right above is the first I built in a bedroom of my apartment in East Palo Alto in 1982. The rods that squeeze the blocks together are running lengthwise in it and the the other as well. The table on the left has a steel top 3/16" thick, with cement patching material between it and the block surface. The bedroom window was covered with cardboard and black plastic. The lasers were in the other bedroom with their beams going through shuttered holes in the wall. I was on the ground floor slab in the corner of a three floor apartment building, and routinely did exposures up to around five minutes if I remember correctly with a 30mW HeNe laser. The pic below shows the table I built in 2003 in a metal sculptor's studio in San Jose. The rods run across the table instead of lengthwise, and I used three legs instead of four. Same 4x8' Newport breadboard, which is now on its edge in the garage until I fix the garage. I fully supported the plywood base while laying out the cinder blocks to make them as flat as I could before squeezing them together. [[Image:ConcreteBlock2.jpg]] ====Commercial Tables==== Commercial Tables are the stiffest most versatile tables available. They come with tuned legs or active dampening. While there are by far the best they are also the most expensive. [http://www.newport.com/Table-Specifications/140219/1033/catalog.aspx Newport] is one of the premiere manufactures. 57b08a1b9b26f28d54ca915071df5bb1cdc88bf2 0 214 275 2008-01-05T20:16:55Z Colin Kaminski 0 wikitext text/x-wiki Diffusers can be used to soften the shadows from the object beam for softer lighting effects. From a artistic lighting standpoint, a laser is considered a point source. To make softer lighting we need to widen the beam source. There are many ways to do this: *Broken Light Bulbs *Sandblasted Glass *Etched Glass *Glass or Plastic sanded in one direction only Commercial diffusers are also available. You can specify how much diffusion you need. A 10% diffuser allows most of the light to pass through. A 30% diffuser spreads more of the light. It should be remembered the diffusers also randomize the polarization. This can increase the fog level of the hologram. It is very important the the diffuser be shielded from the plate so no stray light can hit the plate directly. ae42fed899c7a48d9ebc34c466c95c78475e8965 0 176 199 2008-01-05T20:19:24Z Colin Kaminski 0 wikitext text/x-wiki ===Blocking Un-Wanted Beams and Stray Light=== Stray light becomes an ever more complicated problem as the setups contain more optics. Blocking unwanted light is a requirement of making good holograms. There are many kinds of unwanted light. ====Stray Light from Optics==== Stray light from optics comes in many forms. Painting the edges of lenses with black paint is a good start at taking care of un-wanted light. The best way to stop unwanted light is to look through the plate holder and place a black card in the way of any light getting to the plate that is not from the main beams. There are special papers available but black poster board will work in a pinch. It is important to pay special attention to the collimation mirror. ====Back-Reflections Re-Entering the Laser==== Back-reflections into a laser can be a problem, as the reflecting surface can form together with the laser cavity mirrors an unstable resonator configuration. This can lead to a chaotically fluctuating laser output with many extra unwanted [[Equipment#Longitudinal_Modes_and_Coherence_Length|longitudinal modes]] und intermittend [[Equipment#mode_jumps|mode jumps]], which can easily ruin a hologram. Particularly prone to generate such effects are [[Equipment#Spatial_Filters|spatial filters]], even more so if they use metallic and not blackened pinholes. Especially [[Types_of_Lasers#Diode_Lasersdiodes|laser diodes]] are very sensitive to even minute back reflection. The least expensive solution is to slightly mis-allign all lenses and other reflecting surfaces so their backscatter misses the laser. A more expensive solution is to pass the light through a polarizing cube beam splitter followed by a [[Equipment#Wave_Plates|1/4 wave plate]]. Any light that is reflected back towards the laser will then be deflected 90 degrees off the polarizing cube beam splitter and so won't enter the laser any more. However, this involves [[Equipment#Polarization|circularly polarized]] light and this is often not desirable in holographic applications. The most expensive solution to avoid back reflections is to use a [[Equipment#Faraday_Isolator|Faraday Isolator]]. ====Beams that Represent a Safety Hazard==== Building your optical bench either above or below eye level is the best way to keep the beam safe. Also building side above the laser plane can add a level of safety. Having a laser with adjustable power allows you to lower the poser for alignment and raise the power for exposures is also possible. For very high power lasers that have no adjustable power, using a variable beam splitter to a beam dump can be used. For pulsed lasers a alignment laser can be aimed to be co-incident with the pulsed beam for alignment. If this laser is chosen as a color the film is not sensitive to, it can also be used as a safe light for loading film. ====Beams Dumps==== A beam dump allows one to dispose of the beam without any back reflections and without having it go somewhere that might fog the film. A beam dump consists of a black box with a small opening. Inside the box is a cone that diffuses the light to the sides. When designing your own make sure that the power density on the face of the cone (laser power/area) does not exceed the threshold of damage of the material of the cone. A different beam dump can be made from a glass shade 12 welding filter cut it in half lengthwise. Bounce the beam into the middle of the two plates mounted in parallel so it enters at a 45 degree angle. At each point the glass absorbs much of the light and after only a few bounces the beam is dissipated. 9d727af5a4ed98d01db75f40e4502f4a1c02d093 0 449 1048 2008-01-05T20:22:08Z Colin Kaminski 0 wikitext text/x-wiki ====Gravity Optic Mounts==== ====Magnetic Optic Mounts==== ====Optic mounts for Sand Tables==== ====Simple Optic Mounts==== 90359aa1671810dbd0c305271e0dd44cb6cf4f37 0 235 317 2008-01-05T20:22:58Z Colin Kaminski 0 wikitext text/x-wiki Holding the film stable is a prime requirement for making a hologram. Film holders can be as simple as holding up a glass plate with a couple of magnets. But, it must not be forgotten that the film must be held absolutely stable. Film holder Plans: #[[Machined Film holder]] #[[Angle Iron Film Holder]] 15c26b01f46104830824ad3d0eb9f718f034bcec 0 502 1154 2008-01-05T20:44:08Z Colin Kaminski 0 wikitext text/x-wiki {| align=center border=1 | Material | Thickness (um) | Sensitivity uj/cm2) Sectral Sensitivity (nm) | 442nm | 514nm | 633nm | 694nm | Resolving Power lp(mm)-1 |Grain Size (nm) |- | '''Slavich''' |- | PFG-01 | 7 | <700 | | | 80 | | >3000 | 35-40 |- | PFG-03M | 7 | <700 | | | 1500 | | >5000 | 10-20 |- | VRP-M | 7 | <550 | | 80 | | | >3000 | 35-40 |- | PFG-03C | 9 | 400-700 | 1000 | 2000 | 1000 | | >5000 | 10-20 |- | '''Colourholographic''' |- | BB-700 | 7 | <700 | | | 50 | 150 | >2500 | 50-60 |- | BB-640 | 7 | <650 | | | 150 | | >4000 | 20-25 |- | BB-520 | 7 | <540 | 150 | 150 | | | >4000 | 20-25 |- | BB-450 | 7 | <470 | 150 | | | | >4000 | 20-25 |- | '''Kodak''' |- | 131PX | 9 | <650 | 2 | | .5 | | >1250 | 70 |- | 131CX | 9 | <650 | 2 | | .5 | | >1250 | 70 |- | 120PX | 6 | <750 | 60 | | 40 | 40 | >1250 | 70 |- | 120CX | 6 | <750 | 60 | | 40 | 40 | >1250 | 70 |- | '''FilmoTec-ORWO''' |- |GF40 (gelantin film) |6 | UV to blue-green after sensitisation | | | | |not relevant | |- | HF53 | 6 | <550 | |1000 at 535nm | | | >5000 | |- | HF55 | 6 | <550 | |250 at 535nm | | | >3000 | |- |HF65 |6 |580 to 660 | | |<100 | |>3000 | |- | '''Ultimate''' |- | Ultimate 15 | 7 | <700 | | 150 | 150 | 150 | >5000 | 15 |- | Ultimate 08 | 7 | <650 | 120 | 200 | 200 | | >7000 | 8 |- | '''Fuji''' |- | HL-30 | | 100-200 | | | | |3000 |30-40 |- |} b455b4b9391b1cd1d893ba01c227d577056983f4 0 236 319 2008-01-05T21:41:24Z Colin Kaminski 0 wikitext text/x-wiki Fixer removes the unexposed silver halide remaining on a hologram leaving behind the reduced metallic silver that forms the image. By removing the unexposed silver halide, the fixer prevents any further reaction of the silver salts and ensures a permanent image. Most fixers are based on the thiosulfate ion, especially ammonium thiosulfate. Sodium thiosulfate or 'hypo' was the commonly used fixer. Both fixers work best in acid conditions and this is usually created using small quantities of acetic acid. e1f95c7b90e22a98713bad2503d39cafa1b89d63 0 410 970 2008-01-07T07:47:23Z Colin Kaminski 0 /* Power */ wikitext text/x-wiki The word laser is an acronym for Light Amplification by the Stimulated Emission of Radiation. [[Image:Laser_Spectrum.png]] For a simple explaination about LASERs read [[How Do LASERs work?]] Information about [[Types of Lasers]] can be found here. ====Laser properties==== =====Color===== The color of a laser is related to the physics of the lasing medium. Holography grade lasers are made in almost every color of the rainbow from UV to IR. The most common colors (lines) used for holography are 650nm red ([[Types_of_Lasers#Diode_Lasers|laser diodes]]), 633nm ([[Types_of_Lasers#HeNe_Lasers|Helium-Neon Lasers]]), 532nm (frequency doubled Yag [[Types_of_Lasers#DPSS_Lasers|DPSS lasers]]) , 514nm and 488nm ([[Types_of_Lasers#Argon_Ion_Lasers|argon lasers]]). =====Power===== Power is the measurement of the energy contained in the beam. For continuous wave lasers (CW) is is measured in milliwatts (mw) or watts (W). The more power a laser has the shorter the exposure time will be, and consequently, the less stringent the constraints on table stability are. While it is possible to create holograms with laser powers of 1mW and less, 5mW or more is recommended in order to have conveniently short exposure times for usual film sizes. On the other hand, going much beyond this power level creates a severe danger for the eyes; in principle, one should always use as little power as necessary for a given application. Typical power levels of [[Types_of_Lasers#HeNe_Lasers|HeNe lasers]] are 1-20mW, of [[Types_of_Lasers#Diode_Lasers|diode lasers]]: 5-50mW, of [[Types_of_Lasers#DPSS_Lasers|DPSS lasers]]: 20-200mW, and of [[Types_of_Lasers#Argon_Ion_Lasers|argon lasers]] with etalon: 100-500mW. But, if the money is no object powers of over 1 watt can be obtained in Argon and DPSS lasers. The power for pulsed lasers is measured in Joules. Most holographic Pulsed laser systems fall into the .1 to 10 Joule range and are of a [[MOPA]] design and either Frequency Doubled ND:YAG/ND:Glass lasers or Ruby Lasers. =====Divergence===== Laser beams do not stay the same diameter as they travel. They expand and the rate of the expansion is measured in millirads. The divergence of a laser is of little importance to holography. However when blending lasers of different frequencies for color work it is important to match the divergences. =====Polarization===== While any [[polarization]] state will make a hologram a polarized laser will make the most efficient holograms. Lasers are usually classified as either non-polarized or a polarization ratio is specified like 100 to 1. When a laser is listed as non-polarized it means that there are no optics to set the polarization angle. This does not necessarily mean the beam is not polarized but often that the polarization of the beam rotates as time passes. In order to set the polarization of a laser there needs to be a polarizer in the cavity. The most common polarizer is an optic set at the [[Brewster's Angle]]. I can be one of the cavity mirrors or a window in the cavity. =====Transverse Modes===== [[Image:PolarizedModes.png]] This image shows the modes for polarized lasers. A laser for holography needs to be TEM00. This stands for Transverse Electric Mode. It is a measure of how even the laser beam is in cross-section. Using a laser with a higher order mode makes it impossible to get even illumination, and also the individual spatially distinct beam components may not be in phase with each other (ie, cannot interfere to form a hologram). A TEM00 beam has a [http://en.wikipedia.org/wiki/Gaussian_beam Gaussian] distribution. =====Longitudinal Modes and Coherence Length ===== Besides various [[Equipment#Transverse_Modes|Transverse Modes]], a laser can also emit various longitudinal modes which have just slightly different wavelengths. This is because the resonance condition can be satisfied by many different wavelengths. That is, assuming the laser resonator has length L, it allows all modes to be present whose wavelength lambda satisfies L= N lambda/2, where N is an integer. So if lambda is very small (like 600nm) and the condition is satisfied by some very large N, then it is also satisfied by a slightly different lambda and a slightly different N. The frequency difference of two adjacent modes is called mode spacing and given by delta_f = c/(2L). In practice, the laser material won't amplify any possible resonance mode, but only frequencies that lie within a certain gain window, so at most a few longitudinal modes will be able to lase. With special methods, like using an [[Equipment#Etalon|etalon]], one can achieve a clean single frequency operation. The presence of more than one longitudinal mode is a serious obstacle against recording holograms with significant depth. The reason is that when several modes with slightly different wavelengths are present, they will be out of phase after having traveled a certain distance D. The quantity D is customarily called <b>coherence length</b>. It leads to a blurring of the interference fringes when the path difference between object and reference beam becomes comparable to D. In other words, the maximal recordable depth of a hologram is in the order of D. If one has a single longitudinal mode, then D is essentially "infinite". In practice, it is then governed by the line width of the laser emission, and this can be very small (like one Mhz, which corresponds to D=150m). When two or more modes are present, then their frequency difference delta_f is what dominates the coherence length. The mode spacing is generally given by the resonator length L, so if two modes are present, then the coherence length is approximately D=L. If three are present, then the frequency difference between the most distant modes is twice as large as before, so D=L/2. And so on... if M modes are present, then the coherence length is approximately D=L/(M-1) (this assumes, for simplification, that all the modes have equal strength). All this is illustrated by the following figure. The coherence length is measured by a [[Interferometry|Michelson Interferometer]], and given by the maximal path length difference where reasonable fringe contrast occurs. On the left various laser spectra with different longitudinal modes are shown (the dashed line symbolizes the gain profile). On the right, shown are the corresponding interference patterns that arise when translating the movable mirror (mathematically speaking, they display the [http://en.wikipedia.org/wiki/Fourier_transform Fourier transformation] of the spectrum). The important point is that the fringes blur in a way that depends on the details of the laser spectrum. [[Image:Coherencelength2.jpg]] The following scenarios are shown: <ul> <li>A: Single frequency operation - the coherence length D is basically infinite. <li>B: Two modes oscillate, so the coherence length D is basically L. Assumed is that the lines are quite close (L is large). <li>C: Again two modes oscillate, so again D=L. But here L is assumed to be small, resulting in a shorter coherence length than before. <li>D: Four modes oscillate, so D=L/3 is quite a bit shorter than before. This scenario is typical for powerful lasers with a lot of gain. </ul> For example, for a [[Types_of_Lasers#HeNe_Lasers|Helium Neon laser]], the gain window is typically 1Ghz. Assume the resonator length is L=60cm, then its mode spacing is c/(2L)=250Mhz. Thus up to four modes can be present simultaneously, and if this is the case, then D=60(4-1)=20cm. This is a reasonable value for recording most holograms. For an [[Types_of_Lasers#Argon_Ion_Lasers|argon laser]], due to the high plasma temperature the gain window is like 10Ghz. Assuming again that L=60cm, up to 40 modes can simultaneously lase, and the coherence length will be approximately D=60cm/39~1.5cm. This allows to record only very shallow holograms! Thus, an etalon is pretty much required. For a [[Types_of_Lasers#Diode_Lasers|diode laser]], the resonator length is very small, and the mode spacing can be 100Ghz. This means that the moment two or more modes lase, the coherence length drops down to a fraction of an inch. Thus, multi-frequency operation of a diode laser must be avoided by all means! In practice, the way to the determine longitudinal mode structure and coherence length of a laser is either by setting up a [[Interferometry|Michelson Interferometer]] as shown above, or by directly displaying the laser spectrum by a scanning Fabry-Perot interferometer. See [http://www.repairfaq.org/sam/laserlia.htm#liasfpi Sam's] and [http://argonholo.webhop.net/laser/SFPI.html W'] notes on home-built SFPI's. For diode lasers with a large mode spacing, the longitudinal spectrum can be most conveniently displayed by a grating based optical spectrum analyzer with sufficient resolution (better than approx 0.2nm). Such a device can be build in a simple manner by using a CD or DVD as grating, in combination with a path length of several meters. I had to add this example for calculating coherence length from the forum. From Iovine's "Homemade Holograms" p. 154: If you know the range of frequencies: CL = c / (2 * range in Hz) - c is speed of light in m/sec For a range of wavelengths: CL = (center wavelength in meters)^2 / (2 * range in meters) Example: laser diode at 670 nm with wavelength range of 0.2 nm should have a CL of (670 * 10^-9)^2 / 2 * (0.2 * 10^-9) = 0.0011 meter. =====Mode Hops ===== There are often a number of sable longitudinal modes that can exist in a laser cavity. If the laser jumps from one to the next it is called a [[Mode Hop]]. A [[Mode Hop]] will destroy a holographic image causing "banding" or "sliced bread" holograms. ====Known Lasers that work for Holography==== *Spectra Physics Model 164 with prism (single line operation) and etalon (added coherence) *Spectra Physics Model 165 with prism (single line operation) and etalon (added coherence) *Infiniter 200 Laser Pointer *Integraf Laser Diode *Coherent C315 DPSS 532nm *Lexel 85 Argon Laser with wavelength selector and [[Etalon]] *Lexel 95 Argon Laser with wavelength selector and [[Etalon]] *Most tubular black casing HeNe lasers More information about [[Types of Lasers]] is available [[Types of Lasers|here]].<br> A most detailed discussion of lasers for the amateur can be found in [http://www.repairfaq.org/sam/laserfaq.htm Sam's Laser FAQ]. bc78c530fa29d3a76d7e851bc1f4a57ed01a565e 6 299 501 2008-01-08T07:08:49Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 391 921 2008-01-08T07:09:37Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 352 789 2008-01-08T07:10:16Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 354 801 2008-01-08T07:10:52Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 378 891 2008-01-08T07:11:34Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 289 461 2008-01-08T07:14:48Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 374 875 2008-01-09T18:51:52Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 591 1332 2008-01-10T06:19:14Z Colin Kaminski 0 wikitext text/x-wiki Wave plates consist of some birefringent material (like quartz) and modify the [[Polarization]] of a laser beam. Lambda/4 wave plates (also called 1/4 waveplates) turn linearly polarized light into circular polarized light, and as such are not of great use to holographers. Lambda/2 wave plates (also called half-waveplates) rotate the [[Polarization]] of a laser beam by a fixed amount, depending on the orientation of the preferred axis. They thus need to be fixed in a rotation mount. A waveplate is usually only usable at a single frequency, in order to rotate the polarization of a multi-colored laser beam see [[Fresnel Rhomb]]. Lambda/2 wave plates are often used by holographers for the following reasons: *For rotating the polarization of a laser to avoid holograms with superimposed "wood grain" structure. This arises from interference between beams reflected from the front and back sides of a holographic plate. One technique to avoid this is to use [[Index Matching]], but a simpler method is to illuminate the plate by a reference beam at the [[Brewster's Angle]]. When properly polarized, there won't be any reflections and thus, no interference. When the reference beam is tilted horizontally (vertically), then one needs horizontal (vertical) linear polarization of the laser beam. Small lasers like tubular HeNe lasers can simply be rotated to achieve the correct polarization, but this won't work for larger lasers like [[Types_of_Lasers#Argon_Ion_Lasers|argon lasers]], which are usually vertically polarized. For these, a Lambda/2 (half-wave) waveplate can be used to rotate the polarization appropriately. *For rotating the polarization of the reference with respect the polarization of the object beam, to maximize image contrast or to achieve special effects. If you put a polarizer at the film plane aligned to the polarization of the unaltered object beam so you can see the reflections and place a 1/2 wave plate in the object beam you will see the relative brightness of the reflections dim as you rotate the polarization off axis. Rotate the 1/2 wave plate so the reflections and the diffuse light from the object have the "desired" brightness. Also, make sure that any bright spot is not exactly on the film plane when making an H2 or it will burn out. *In conjunction with a [[Holography_Technology#Cube_Beamsplitters|polarizing cube beam splitter]], a pair of Lambda/2 plates is the best method to split a laser beam into two beams with a variable beam ratio. Wave plates are usually quite wavelength dependent and will work well only very close to their design wavelength. Multi-order waveplate are more wavelength sensitive than zero-order wave plates. There exist however broad band wave plates as well. Usually wave plates are expensive and not too often available as surplus - if you see one, get it! For the hobbyist, there are also the following two options: *If she happens to have a few waveplates designed for other wavelengths than the desired one, try to mount them in tandem and play with their relative orientations: there is often a spot where a linear rotation can be achieved. Even using Lambda/4 wave plates can sometimes work in this way. Another reason to catch any conceivable wave plate on ebay! *LCD screens from old electronic pocket games (in particular Nintendo types from the early 80's) sometimes can be used as broad band Lambda/2 wave plates. This needs to be tried case-by-case. The relevant piece is the top glass plate that needs to be taken off. The disadvantage is often poor optical quality (can be remedied by a [[Holography_Technology#Spatial_Filters|spatial filter]]), and interferences from front and back sides that lead to an uneven illumination. Commercial wave plates are usually anti-reflection coated and so avoid this problem. *Stacks of Seran Wrap can also be stacked to the right thickness for a quick and dirty wave plate. *If you take a piece of mica and flake a few flakes off one may be the right thickness to be a multiorder wave plate. This is another quick and dirty method. 336dffb7800a6bbffb331dc684083a8b6848004d 0 238 323 2008-01-10T06:20:29Z Colin Kaminski 0 [[Fresnel Romb]] moved to [[Fresnel Rhomb]]: Spelling wikitext text/x-wiki [[Image:FresnelRomb.jpg]] From: [http://www.klccgo.com/fresnelrhomb.htm Karl Lambrecht Corporation] Used to rotate the polarization. The advantage as compared to [[Holography_Technology#Wave)Plates|Wave Plates]] is their broadband nature, as they are typically useful throughout the whole visible spectrum. 5729860a69a81d4b3698f3456d3328ae927ac3f3 0 500 1150 2008-01-10T06:23:11Z Colin Kaminski 0 [[Silver Film]] moved to [[Silver Film Comparison Chart]] wikitext text/x-wiki {| align=center border=1 | Material | Thickness (um) | Sensitivity uj/cm2) Sectral Sensitivity (nm) | 442nm | 514nm | 633nm | 694nm | Resolving Power lp(mm)-1 |Grain Size (nm) |- | '''Slavich''' |- | PFG-01 | 7 | <700 | | | 80 | | >3000 | 35-40 |- | PFG-03M | 7 | <700 | | | 1500 | | >5000 | 10-20 |- | VRP-M | 7 | <550 | | 80 | | | >3000 | 35-40 |- | PFG-03C | 9 | 400-700 | 1000 | 2000 | 1000 | | >5000 | 10-20 |- | '''Colourholographic''' |- | BB-700 | 7 | <700 | | | 50 | 150 | >2500 | 50-60 |- | BB-640 | 7 | <650 | | | 150 | | >4000 | 20-25 |- | BB-520 | 7 | <540 | 150 | 150 | | | >4000 | 20-25 |- | BB-450 | 7 | <470 | 150 | | | | >4000 | 20-25 |- | '''Kodak''' |- | 131PX | 9 | <650 | 2 | | .5 | | >1250 | 70 |- | 131CX | 9 | <650 | 2 | | .5 | | >1250 | 70 |- | 120PX | 6 | <750 | 60 | | 40 | 40 | >1250 | 70 |- | 120CX | 6 | <750 | 60 | | 40 | 40 | >1250 | 70 |- | '''FilmoTec-ORWO''' |- |GF40 (gelantin film) |6 | UV to blue-green after sensitisation | | | | |not relevant | |- | HF53 | 6 | <550 | |1000 at 535nm | | | >5000 | |- | HF55 | 6 | <550 | |250 at 535nm | | | >3000 | |- |HF65 |6 |580 to 660 | | |<100 | |>3000 | |- | '''Ultimate''' |- | Ultimate 15 | 7 | <700 | | 150 | 150 | 150 | >5000 | 15 |- | Ultimate 08 | 7 | <650 | 120 | 200 | 200 | | >7000 | 8 |- | '''Fuji''' |- | HL-30 | | 100-200 | | | | |3000 |30-40 |- |} b455b4b9391b1cd1d893ba01c227d577056983f4 0 489 1128 2008-01-13T16:14:10Z Colin Kaminski 0 wikitext text/x-wiki blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> 1dcf5788845dad70cef5d1463b6383542e065f7c 0 190 227 2008-02-03T16:11:49Z Colin Kaminski 0 /* Mirror Cleaning an Observatories Approach */ wikitext text/x-wiki The best way to clean a mirror is to not get it dirty ever! '''Don't ever touch the front of a mirror!''' Since you are reading this I'll assume that, like me, you have let your mirrors get dirty. Cleaning a first surface mirror will damage the surface so it is our goal to damage it as little as possible. We will assume that, like most mirrors, yours is aluminum with a protective overcoating. For instructions on cleaning mirrors that are dielectric coated (not silvered) see [[Cleaning Coated Optics]]. The first thing to try is gently blowing the mirror off with compressed air. Use a commercial can or make sure your compressor air is filtered and dried. If that doesn't get it clean, or clean enough, you'll have to go the more dangerous route. ==Washing your mirror== [[Image:NalgeneBottle.jpg]] A Nalgene Wash Bottle can be useful to store solutions used for washing. The next thing to try is to wash the mirror. A common amateur astronomy recipe is to take 5 gallons of warm water (not hot) and add 1 teaspoon of '''Ivory Liquid''' dish washing soap. Bob Hess recommends using more soap, Like 1 oz per Liter of '''distilled''' water. *Mount the mirror face up in a sink, so that it's off the bottom. (You don't have any rings on right?) *Be certain to thoroughly clean the sides and back of the mirror, without touching the front, before attacking the front. Otherwise, you will probably contaminate the cleaning fluid with particles that will scratch the coating. *Blast off loose dirt with water flow in the sink. *Rinse with distilled water. *Prepare some surgical cotton wads cut from a large roll into a bunch of grapefruit sized pieces. Don't use cotton balls. They turn to mush and seperate in the soapy water. Get a big roll of surgical cotton at the pharmacy, and make a bunch of grapefruit sized wads before wetting the mirror. *Pour some of the soap solution onto the middle of the mirror. Wet a cotton wad, and use it to move the soap from the center straight to the edge, in a spoke like pattern, turning the wad to use a new face for each wipe. Let the weight of the wet cotton be the only force on the mirror. (Do Not Rub!) *Add more soap and/or distilled water as needed. *Use the last of the soap and the cotton wads to gently swish around on the surface. *You may remove the mirror to examine it but do not let the soapy water dry! No longer than 30 seconds! *Rinse with a gallon of distilled water. *Follow that with 99% isopropanol, and blow dry fast with a hair dryer. *Touch up any residual marks with methanol on lens tissue. *Check mirror for any dust that settled during drying. Remove with a new fine point artists brush. Now you should have a clean mirror. Try as much as posible to keep your mirrors clean to avoid the risk of damaging them when cleaning. ==Using Collodion== The subject of using collodion came up on the [http://www.holographyforum.org/phpBB2/index.php Holography Forum] with and collodion has been used for some time by astronomers to clean their [http://webari.com/oldscope/atspages/techtips.htm precious mirrors]. Note that you should be careful using collodion on cheap mirrors as it [http://www.dragonseye.com/blog/archives/92-Optic-cleaning-with-collodion.html can remove the silver]. If it's truly a cheap mirror though, you may just want to replace it. The first thing to do is create a tape dam around the mirror so the collodion doesn't just drip off the edges. http://www.dragonseye.com/gallery/d/3690-2/06020004.jpg Follow that by pouring a small amount of collodion on the mirror and rotating the mirror in a circle to distribute the liquid. This will take a bit of practice but it's easy to repeat the process after the collodion has dried. Once the collodion has dried (anywhere from five to ten minutes) remove the tape and you should find that the collodion will come up with it if it hasn't already started to curl up on its own. If any of the collodion stays behind you can either remove it with some tape or dribble a bit more liquid on the stuck part and you'll find it's easier to remove after the new liquid has dried. You should find that after a treatment with collodion that the lens or mirror is as clean as it was when new. http://www.dragonseye.com/gallery/d/3699-2/06020008.jpg ==Mirror Cleaning an Observatories Approach== Used with permission from http://www.arksky.org/asoclean.htm#mirrors. ===THE CLEANING OF OPTICAL SURFACES: MIRRORS=== Front surface mirrors, secondary mirrors and mirrored diagonals by P. Clay Sherrod, Arkansas Sky Observatories The cleaning of front surface mirrored surfaces is much, much different than that of refractive optics; many times the reflective surfaces might be of deposits of enhanced silver or aluminum which may or may not be overcoated with some protective layer (usually a molecule-thick layer of Silicon Dioxide or similar) of transparent material. Your first step in attempting to clean ANY reflective optics is to first ascertain whether or not your mirrored surface is indeed protected by such a coating, since the cleaning solution AND procedure to clean without damage is quite specific for protected vs. unprotected mirror surfaces. Note that the following discussions include all reflecting optics: primary mirrors, secondary mirrors (both flats and curved), mirror diagonals and any ancillary optical equipment which uses a mirror in the optical interface. ===DETERMINING MIRROR PROTECTION=== A very simple rule for deciding whether or not your mirror surface is protected: if you do NOT know, assume that it is NOT coated. Most manufacturers of Newtonian mirrors supply the finished product with a coating of silicon dioxide over the final aluminized or silvered coatings; ASK whether your mirror is coated....if you cannot get an answer, then assume that it is not. On the other hand, most primary and secondary mirrors of popular catadioptic (Schmidt-Cassegrain and Maksutov) are NOT protective-coated unless otherwise specified. There is a good reason that many manufacturers do not put protective coatings on telescope mirrors: they can reduce performance, both in terms of optical figure (irregularities in deposited protective coatings can change the wave front of your mirror) and in terms of reflectivity (many new mirror systems have "enhanced" coatings which contain highly reflective alloys in addition to aluminum. However, since most enhanced coatings also contain the element SILVER, and since silver tarnished instantly with exposure to oxygen, the chances of enhanced optics being overcoated are pretty good in your favor. Attempts to clean uncoated optics can result very quickly in permanent damage: sleeking (leaving streaks within the coatings themselves) or spotting is very common, even if the utmost care has been used. Never, should any cleaning agent whatsoever be used on unprotected mirror surfaces or damage will occur 100 percent of the time. Simply do not take the chance. ===CLEANING IN RELATION TO MIRROR ACCESS=== In some modern telescopes, it may be undesirable OR even impossible to totally remove the primary mirror for the typical consumer and end-user; thus cleaning will likely take place less often than it would if the mirror were smaller or easy to remove from the optical tube assembly. Remember my Number One Rule on Optics Cleaning: "Don't....unless you absolutely have to." Number Two Rule is: "Brush first and then determine if cleaning is still necessary." Brushing optics and carefully using compressed air to blow off particulates such as pollen and dust can usually get the mirror or optics back into top shape, and cleaning should be done only if there are stains or excessive spotting beginning to build up on the mirror's surface. With catadioptic commercial telescopes, cleaning the primary should be avoided at all costs....prevention is the best care you can give the optics of these telescopes: keep the back opening plugged at all times, even when briefly removing accessories....plug it up until you are ready to insert a new gadget. This keeps both dust and insects from floating in AND it prevent humidity and damaging environmental pollutants from entering the inside of the OTA. In one of the following procedures, not that I discuss cleaning (essential cleaning only....) the mirror of a commercially-built catadioptic by leaving the mirror IN PLACE. Never attempt to remove the mirror of these telescopes unless you have experienced and competent assistance. ===CLEANING SOLUTIONS FOR FRONT SURFACE MIRRORS=== To preface any discussion about what is needed for cleaning mirrors, it is important to note that complete immersion cleaning of most large (i.e, Newtonian) mirrors is recommended, and thus the "solution" quantity is much greater. There is no need to make up batches of cleaning solutions and store....just make it when you get ready to clean your mirror. Essentially all that you are going to need are two pairs of surgical cotton gloves, a clean terrycloth towel, a small amount of IVORY dishwashing liquid, a jug of distilled water and a few white Kleenex tissues.....oh, a large sink, bathtub, or basin. Conversely, to clean unprotected mirrors requires ONLY a very small amount of high pure alcohol content solution and nothing more, since ONLY spot cleaning should ever be attempted; if any unprotected mirror surface becomes so pitted or stained that whole-mirror cleaning is needed.....it is time to send the mirror and/or OTA in for a complete re-coating job. No exceptions. ===CLEANING MIRRORS WITH PROTECTIVE OVERCOATING=== Again, if there is any doubt whatsoever that your mirror has protective overcoatings, assume that it does NOT have protection or be prepared to face the consequences. IMPORTANT NOTE: rarely do secondary mirrors and diagonal mirrors have any protective coating; always assume that they have front surface exposed enhanced coatings and never clean except as described later. 1) In a basin large enough to hold your mirror and still have adequate room for your hands to grasp around the edges, prepare a solution of the following: (based on one-half full kitchen sink quantity....this does not have to be exact! For larger basins, such as a bath tub or wash tub, use proportionately similar detergent-to-water ratio) a) warm, not hot tap water in which you have added ONE TEASPOON of Ivory Liquid dishwashing solution....do not be tempted to use more. b) a thick folded towel placed on the floor of the basin; c) turn off all fans, vents and central heating/air during this process! 2) Remove all jewelry, including wrist watch and put one pair of the TWO pairs of new surgical cotton gloves on your hands 3) For Newtonian and similar mirrors, first remove the mirror and its cell from the telescope OTA; then remove the mirror from the cell...remember, NEVER touch the front surface of your mirrors...your fingerprint contains acid and oils and can be the most damaging element to your mirror! NOTE: as with all glass, telescope mirrors become incredibly slippery and hard to handle when wet. Make every precaution to protect the mirror and you will be safest is you "assume the worst" and prepare for the mirror to slip. This means putting a large folded clean towel in the floor of the basin in which the cleaning will be done; having another clean towel folded against a wall and resting on the floor where the mirror will dry. 4) Place the mirror FACE UP carefully down in the basin, resting on the towel, making sure that you have enough solution to completely cover the entire top surface completely. 5) Allow mirror to soak for at least 5 minutes but NO LONGER than 15 minutes. Do not touch the surface of the mirror at this time. 6) While soaking mirror, remove the cotton gloves and place them in the solution with the mirror to prevent contamination. 7) After about 5 minutes refit gloves but do not touch anything outside of the basin; at this time you are going to very, very gently - with NO pressure - massage against the front surface of the mirror with the tips of your fingers....do NOT rub and do not use any type of cloth or tissue at this point, only fingertips [[note that you MAY use Kim-Wipes or Intrinsic type pads for this process]]. It is fine to "lay down" your fingers and cover more surface.....your are essentially "buffing" the entire surface with the dishwashing liquid using only fingertips. 8) Once done, rotated the mirror 90 degrees and once again massage the entire surface. 9) Occasionally tilt the mirror out of the water for only 30 seconds maximum and examine it.....if there are places that you missed, it will be obvious; if need be, run a very gentle stream of water out of the tap or pour from a pitcher across the mirror and examine while wet; return to basin and massage needed areas until entire mirror is uniformly clean and free of streaks. 10) Leaving the mirror flat in the basis, remove all soapy water from the tub but LEAVE the towel beneath the glass for safety; as the water recedes, begin flushing the surface of the mirror immediately with cold tap water...NEVER ALLOW THE MIRROR SURFACE TO DRY! 11) [note: an assistant is quite helpful at this point!] - Once the mirror has been flushed adequately with tap water, begin tilting the mirror upward at about a 45-degree angle; placing an adequate mass of towels behind it is helpful, but careful to not let the mirror slip in the basin! CONTINUE flushing with tap water while doing this...do not let the mirror go dry......have a pitcher of distilled water within reach and shut off the tap water, and immediately flush with distilled water; allow the flush to drip off the mirror and do it again, using only distilled water. 12) REMEMBER - your gloves are soapy....once you have reverted to the distilled water rinse REMOVE the cotton gloves and work with your bare hands only, being careful to only touch the edge of the glass and never touch the optical surface. 13) Lift the mirror out, keeping the surface vertical to the floor and immediately place on the waiting towel on the floor and lean the mirror carefully at a sharp angle against a wall....use extra towels to assure that the mirror will not roll nor tumble. The angle allows the liquid to roll off the surface, thereby reducing substantially the amount of dry water spotting that can occur. NOW, put the second pair of cotton gloves on your hands for safe handling of the mirror from this point forward. 14) After only TWO MINUTES maximum in the drying position (#12), identify any beads of water that are NOT rolling off the surface; these can be easily removed by "wicking", a process in which you roll up a white Kleenex tissue into a "pencil" and touch to the drop...NEVER RUB.....the tissue will wick the water up off the glass and safely away. 15) Allow to air dry, (with ALL VENTS from air conditioning/heating closed!) for one hour. 16) Some dust might accumulate during the drying process....use a quality soft artists square tip (see Cleaning Refractive Optics, Part One) brush to remove such lint, but ONLY after one hour of drying time! ===CLEANING PROTECTED MIRRORS WHICH CANNOT BE REMOVED:=== The above procedure allows for cleaning a primary mirror which can be removed and immersed in a basin; some protected mirrors (i.e., larger Newtonians, some newer SCT and RC catadioptic telescopes) are made in such a way that mirror removal is very difficult or should NOT be attempted. You clean this in three steps. [DISCLAIMER: From experience, I will state that such mirrors should NOT be cleaned, only brushed and blown off with compressed air; I do not, nor does ASO, recommend the following cleaning procedure; the following procedure can be used by skilled and experienced persons in telescope maintenance, but is not recommended for the normal owner/operator of telescope systems. This is the procedure and technique used in the ASO Supercharge and only used when absolutely necessary, and we do not assume any liability from product damage from any attempts at such cleaning.] CLEANING LIQUID: For such surfaces, use essentially the same process, but instead of immersion, we are going to give your mirror a "sponge bath" applying the soapy liquid (about one gallon water to each one-half teaspoon of Ivory dishwashing liquid). For this you will NEVER USE TAP WATER, only distilled water for both cleaning and rinsing. RINSING LIQUID: You will also need ONE OUNCE of pure (91% or higher) isopropyl alcohol and one capful of Kodak PhotoFlo per gallon of distilled water for RINSE (not wash). The application of both solution AND rinse MUST be done using either Kim-Wipes (Kimberly-Clark) or Intrinsic Pads (Barnhardt Industries of South Carolina)...never, ever use any cloth, tissue or "lens cleaning cloth" for this cleaning or damage will occur. FINAL RINSE: A final rinse of pure distilled water is absolutely imperative...you must do this final step. 1) Place first pair of cotton gloves on hands 2) Have your one gallon of cleaning solution (distilled water with 1/2 teaspoon of Ivory Liquid) handy with a pad soaking in it; likewise you must have your gallon of RINSE solution (gallon of distilled water with one ounce of pure isopropyl alcohol and one small capful of Kodak PhotoFlo) ready with pad soaking it that as well! Your final rinse with pure distilled water needs to be made immediately, so have that ready as well. 3) Put the telescope so that the mirror is angled sharply, i.e., nearly vertical to the ground....your access to the mirror will limit what angles you might be able to achieve here. 4) Making sure that the wipe or pad is ALWAYS completely soaked, but not dripping all over the inside of the OTA, gently begin wiping (Never rubbing!!) across the top 1/2 of the mirror surface; immediately ...during this process, it is absolutely imperative that you continue to resoak and freshen the cleaning pad...never let it dry out so much that surface tension increases against the glass!! 5) Even though you have only done 1/2 of the mirror (always start at the top), you must now quickly RINSE what you have cleaned, using the fresh pad in the rinse solution; keep an abundant (but never dripping) amount of rinse liquid always against the glass! Once the rinse is made, cover the mirror surface that you just cleaned with adequate distilled water final rinse and proceed to clean the lower one-half of the mirror. 6) Once both halves have been cleaned and initial rinse completed, return to the entire mirror and wipe down with copious amounts of distilled water final rinse (no alcohol); repeat twice. Never use so much that your pad is dripping into the telescope tube assembly. 7) Check for water drops that are not quickly evaporating....use a "Kleenex pencil" as a wick to soak up those drops...never rub! 8) Allow to dry in vertical position, with OTA end cap open but with soft cotton sheet over front, for about one hour. 9) Remove any lint or dust with brush or blow off, but do not attempt until after one hour. USE EXTREME CARE IF ATTEMPTING THE AFOREMENTIONED PROCESS and never attempt unless it is absolutely imperative. ===CLEANING MIRRORS WITHOUT PROTECTIVE OVERCOATING=== Very much unlike the previous discussion, cleaning unprotected mirror surfaces should be a "last resort" and is NOT recommended to the normal telescope user. Only if fingerprints, bug droppings, pollen sap, etc. collects on the unprotected mirror surface should any attempt be made to clean. Brushing is encouraged, but cleaning is discouraged. For this cleaning, you need ONLY a quart bottle of pure isopropyl alcohol (91% is the minimum....94% is far better) and either Intrinsic wipes (Barnhardt Industries) or pure white Kleenex with no additives....NEVER use cotton or cotton balls to clean. Never use Q-tips for cleaning small surfaces, only the pads or tissues as specified. NEVER attempt to clean the entire surface of ANY unprotected mirror, whether it be a primary mirror or a small flat mirror in your diagonal assembly. Clean ONLY spots and areas needing cleaning. IMPORTANT: never attempt to clean any spot larger than one inch using this procedure. Use only the following procedure: 1) Place a bright light so that it shines directly onto the surface to be cleaned; you need to be able to see the reflection of the light as well as move your line of sight to inspect so that the light does not shine directly back at you; viewing both ways allows you to examine for streaks and also can assist in preventing you from "over-rubbing" any cleaned area; 2) Put on cotton surgical gloves and locate your area to be cleaned. 3) Put ample alcohol onto your pad or tissue, making it soaked, but not dripping. 4) Very gently wipe the solution across the stain...do NOT rub at all...not one bit. Rubbing will remove your coatings! 5) Follow that wipe with a second one using a totally different wipe or tissue, also soaked with alcohol. 6) Finish by wiping off excess with a fresh dry wipe.....no rubbing, only a light swipe across the surface! This method can be used on secondary mirrors, unprotected primary mirrors and enhanced coated diagonal mirrors. HOWEVER, such cleaning is a last resort....never clean unnecessarily and never clean unless it must be done. Remember what we have always preached at ASO: the single most damaging thing that you can do to your precious telescope optics is to CLEAN THEM. While it is perfectly safe to clean the protected primary mirror OR the front corrector plate of a catadioptic (ASO Part One), it is an entirely different undertaking to clean unprotected mirror surfaces. My utmost recommendations concerning cleaning of unprotected mirrors? DO NOT ..... Let those with experience do it for you or live with the small imperfections....when they get too big, it is time for new coatings. Best of luck and enjoy your telescopes...may the stars always shine their brightest through them. Another quality service from your Arkansas Sky Observatory! Part III (coming soon...): "Preventing the Need to Clean - Protecting your Telescope Optics" Dr. Clay ---------------------------------------- Arkansas Sky Observatory www.arksky.org 909f6c9fc0347095ce56ca06e77f4246cbf89078 0 189 225 2008-02-03T16:16:26Z Colin Kaminski 0 New page: ==ASO fine optics CLEANING SYSTEM== PRECISION COATED OPTICAL Lenses, Corrector Plates and other REFRACTIVE GLASS Used with permission from http://www.arksky.org/asoclean.htm. ===PREFACE=... wikitext text/x-wiki ==ASO fine optics CLEANING SYSTEM== PRECISION COATED OPTICAL Lenses, Corrector Plates and other REFRACTIVE GLASS Used with permission from http://www.arksky.org/asoclean.htm. ===PREFACE=== There are many, many variations of high precision, high reflectivity and high transmission coatings presently offered on the market for both amateur and professional scientists who use OPTICS in their respective lines of study. Smaller glass surfaces with high transmission coatings have always been seemingly easy to clean, since the smaller surface area is not as prone to spotting, sleeking and streaking of the cleaner used. On the other hand, large optical surfaces such as telescope lenses, corrector plates and optical glass "windows" are very difficult to properly clean without some residue being left behind as a result of cleaning. The ARKANSAS SKY OBSERVATORY's new protocol for cleaning optical surfaces includes: 1) judging carefully when cleaning is actually necessary; 2) preparation of the optical surface for proper cleaning; 3) a new solution that combines the attributes of all previous formulae and results in very fast, easy, and streak-free results if used properly; 4) the proper new technique that is highly recommended for cleaning. ===WHEN TO CLEAN OPTICS=== Although we are attempting to obtain the best possible light transmission efficiency from our optics by cleaning them free of deposits, film and debris, lock firmly in your memory that cleaning coated optical surfaces is the single-most damaging action that will be done to them, short of actual physical damage or breakage. No matter how careful, how delicate, nor what cleaning solution is used.....every time cleaned will result in a microscopically-reduced optical performance than before cleaning. Note that the coatings themselves - regardless who makes them and from what they are made - are nothing more than molecule-thick deposits of a very delicate film left on the optical surface from a vacuum process in which air is evacuated and the gases of the coating materials are gently and uniformly distributed across the glass surface after the vacuum container is void of air. This system is devoted to the cleaning of large astronomical refractive optics: lens, corrector, and other optical glass; however the techniques discussed here as well as the new ASO SuperPlus Solution is excellent for the cleaning of eyepieces, eyeglasses, binoculars, camera lenses and all other fine coated optical surface. So....the ground rule here is: CLEAN ONLY WHEN ABSOLUTELY NECESSARY. In most cases, dusting alone will lead to tremendous improvement in performance and overall light transmission. ===PREPARATION TO CLEANING=== DUSTING OPTICAL SURFACES: Large area optical surfaces are frequently plagued by DUST, POLLEN, GRIT, DEBRIS and even human skin and airborne hair. If the surface of the glass is allowed to be exposed at a temperature BELOW THE DEWPOINT, these particulates will stick to the glass and will be stubborn to remove. However, for optimum performance, it is essential to, indeed, remove debris from the optical surface. Your optical glass MUST be dusted when: 1) a flashlight held obliquely against the glass reveals a uniform and fairly thick layer of dust, etc; 2) when POLLEN is on the glass, as leaving pollen will result in "pollen sap" leaving a very difficult-to-remove stain on the surface; 3) ALWAYS prior to cleaning the glass with the solution and technique which follows. Never clean optical glass without gently dusting first! You will find in 3 out of 5 cases that merely dusting off the glass is sufficient to greatly enhance your performance back to optimum and that further physical cleaning is NOT necessary after dust removal. There can be a lot of smudges, stains, flecks and streaks on the glass before it actually begins to degrade your optical performance for all but the most exacting (i.e., high resolution planetary imaging, CCD spectrography and photometry, etc.) demands put upon your telescope. To dust, use a SQUARE-CUT (not a tip-cut) very soft brush that is about 2" (50mm) wide with tapered bristles. I have found several excellent such brushes at Lowe's and Home Depot and other stores where quality painting supplies are sold. Look for the very soft and flexible "touch up" and/or "delicate trim" brushes....most of these are short-handled and have the bristles as an angled radius cut. Make sure that the bristles are incredibly soft; I use the "cheek method" for testing softness: take the brush out of its package and push the tiny ends of the bristles hard against the cheek of your face....if they do not "prick" then they are fine for optical use. Another tip on selecting a brush is the number of bristles....the MORE bristles on brushes just described, usually the softer and better the quality. I start dusting by dusting the METAL SURFACES that surround the optics, ridding them of all debris first; just whisk away. Then start at the top of your glass and gently swipe the surface IN ONE DIRECTION....do NOT move back-and-forth with the brush. Stroke in only one direction. Do NOT rub....merely "pull" the brush across the surface and apply no pressure; let the brush do the work for your. Any particles that do not come off with such brush will be removed in subsequent cleaning with liquid if necessary. The object of your dusting is to essential "move" all the particles to the bottom of the surface you are working on...once there you can brush them off the area and actually assist their removal by blowing gently against the areas being brushed. USING COMPRESSED AIR: DON'T. Period. Dusting is easy, although it may take a little more time, and it is more effective. I have found that compressed air is virtually worthless for attempting to gently remove embedded particles on a glass surface and the chances of the liquid propellants within the can being expelled in liquid droplets against the glass is quite great. The ASO SuperPlus Optical Cleaning Solution - how to mix it yourself! There is NOTHING magic about the new concoction developed over a period of about five weeks here at the Arkansas Sky Observatory. SuperPlus Solution is quite simple, and indeed, there are many familiar components that are being used that have been touted in cleaning solutions before. Nonetheless, after hundreds of elixirs and hours later, this combination - in exactly the proportions given below - results in near-perfect results every time! In striving for the "perfect cleaner" the following criteria were evaluated: 1) Streaking - the solution was required to dry streak free with minimal "dry rubbing" which can damage optical surfaces; 2) Spotting - the solution must dry spot-free with minimal rubbing; 3) Safety - the solution was required in all respects to be totally impervious to the optical coatings and totally safe for all variations of them on the market; 4) Simplicity - it needed to be something that anyone could mix up when needed with over-the-counter inexpensive components; 5) Sure-fire - it must work every time the first time....the less rubbing the better. Experiments on all types of optical glass surfaces were conducted with EVERY cleaner offered by all makers and groups; the following SuperPlus Solution was derived as the "best of all of them" since all had some attributes that were worthy, with some extreme cases omitted. Interestingly although some of the solutions that have been previously offered were deemed very hazardous to the quality of cleaning and even the surfaces themselves, some components used within those solutions did HAVE MERIT and have been incorporated! You will be surprised perhaps at the simplicity of this. ===HERE IS WHAT YOU WILL NEED=== Nearly all components should be available locally; suggested outlets for obtaining these are in parenthesis. 1) distilled water (supermarkets) 2) "pure" isopropyl alcohol (pharmacies, drug stores....may have to be ordered) 3) coffee filters 4) "regular" Windex, the blue kind (supermarket) 5) Kodak PhotoFlo solution (camera and photo houses only) 6) Synthetic Cotton Replacement Pads (some finer pharmacies, medical supply companies....ask your local M.D.!!) 7) two "atomizers" or simple squirt bottles for dispensing liquids (Wal Mart or similar) 8) box of KLEENEX [only!] pure white, no additives tissue (supermarket) 9) quart mixing jars, very clean and sterile (try your cabinets!) 10) sterile eye dropper (drug store). ===NOTES ABOUT THE INGREDIENTS=== What an how you combine these components, as well as HOW you use them will make or break your success in streak-free and perfect cleaning; please make note of the following: Pure Isopropyl Alcohol - NEVER use "regular" isopropyl alcohol. Isopropyl is what you commonly see in stores as "Rubbing Alcohol." However, most on-the-shelf varieties is about 70% or less pure....the remaining 30% is impurities which WILL result in streaking and deposits on your glass. USE ONLY 91% OR HIGHER proof isopropyl....this is found on the same shelf typically, in very large and well-stocked pharmacies. If not, simply ask your pharmacist to order some! Expect to pay about double the price of the "store brand." Windex - Many cleaning formulae suggest Windex, indeed from one of the largest optical houses in the world. However, there has always been "something wrong" with Windex in that it leaves a ghostly film on optics. After much experimentation, I have found that it is the heavy impurities that are SUSPENDED in the solution that are responsible for the fog....you CAN get them out as you will see. NOTE that ONLY the blue Windex should be used. NEVER use any cleaner with vinegar on your optics. Kodak Photo-Flo - If you have never used this before NOTE!!! This is extremely concentrated stuff and a tiny, tiny bit goes a very long way! We are talking DROPPER amounts here....NOT ounces. DO NOT USE MORE THAN RECOMMENDED....your results will be horrible. Kleenex - ONLY USE pure white Kleenex, no other brands at all. Do not select Kleenex with "ultra softeners" or with scented oils. Only plain and simple pure white. ===HERE IS HOW TO MIX ALL THIS STUFF=== You are making TWO solutions: 1) Solution 1 - Cleaning Solution: This is the active part of the cleaning and should be mixed very precisely in the quantities provided. 2) Solution 2 - Rinse Solution: This is ABSOLUTELY necessary for most cleaning session; however, you MAY find that you do NOT NEED the final solution if your optics dry streak-free (which likely they will!). SOLUTION ONE: Cleaning Solution. You are going to have much more solution of each component than need for one quart of final SuperPlus Cleaning Solution. Keep all left-over unused and unmixed components well sealed and marked for future use. Step 1: FILTER THE WINDEX VIA THE COFFEE FILTER into a thoroughly washed and dried container; go ahead and filter the entire bottle as this is much simpler and more effective than attempting to filter one ounce. Step 2: FILTER THE DISTILLED WATER using a second clean coffee filter into another jar. Yes, I know that distilled water is supposedly inclusion free, but trust me on this one. Step 3: MIX...... In another quart jar, add the following (do NOT substitute nor change amounts!) a) the filtered and purified WINDEX - 1 ounce b) ALCOHOL - 1.5 ounce c) PHOTO-FLO - two drops...that's RIGHT, I said "two drops"....any more and you will be sorry. And I mean SMALL drops!! (about 1/16th ounce is pushing the limit) Step 4: MIX together gently but do NOT shake. Step 5: ADD 12 OUNCES OF Distilled water. I chose to mix my solution in empty quart plastic alcohol bottles; if doing so, merely fill the bottle to within 1" of the top. Step 6: Pour liquid into your MARKED squirt bottle for use. SOLUTION TWO: Rinse Solution. In 12 ounces of filtered distilled water add TWO drops (only!!) of Photo-Flo solution. No more no less. Transfer liquid into SECOND MARKED squirt bottle. You are now ready to CLEAN your optics. The ASO SuperPlus Cleaning Technique - You CAN do it right! The FIRST time! **tip #1** CLEAN OPTICS ONLY IN THE DAYTIME WITH THE OPTICAL SURFACE "LOOKING" OUT OF A WINDOW OR TOWARD A BRIGHT OPEN SKY **tip #2** NEVER....NEVER...ATTEMPT TO SURFACE CLEAN LARGE OPTICS WHEN THE HUMIDITY IS ABOVE 65% !! Streaking will result. If you attempt to clean your optics when the humidity is high, you will be very disappointed in the results. **tip #3** PLAN TO USE AT LEAST ONE TISSUE PER INCH APERTURE BEING CLEANED....ALWAYS keep a dry tissue to the surface for best results! There is no solution that will result in satisfactory cleaning if your technique is NOT good when cleaning. Unfortunately with cleaning large glass surfaces, you must normally move quickly, but gently in order to obtain a streak-free and spot-free result. If you follow this technique, you can move a bit more slowly and deliberately AND achieve the same results. ** MAKE SURE YOU HAVE DUSTED OFF THE PARTICLES FROM THE GLASS PRIOR TO FURTHER CLEANING! (see above) ** STEP ONE - Turn your telescope so that you are FACING the corrector plate or lens head-on; you are NOT going to use so much liquid that you need to be worried about cleaning solution getting away from you and down inside the retaining rings of the optics. Make yourself comfortable....you may be here a while! I prefer placing the telescope if possible in a position where I can sit down to clean. You must have a small table or area within reach where you will have your Synthetic Cotton Replacement Pads, solutions and Kleenex waiting. STEP TWO - Imagine your corrector plate or lens in QUADRANTS or quarters, like large sections of pie. You are going to begin at the TOP left and work your way down to the BOTTOM left piece of pie. STEP THREE - Gently shake the container (Solution ONE - Cleaner) for just a brief moment and spray a generous amount of liquid onto the Synthetic Cotton Replacement Pad, NOT the glass surface. You want the Synthetic Cotton Replacement Pad WET, but not dripping; make sure you hold the pad only on ONE side and do not TURN to use the side where your fingers have been. STEP FOUR - Begin in your upper left "quadrant" and gently daub (do NOT rub) this section until you have generously smeared the cleaning solution across the surface of ONLY that area. Never "push" the Synthetic Cotton Replacement Pad, only pull. Do NOT rub. The idea here is to ONLY move the liquid across the surface to break the adhesion of film and dirt deposits against the glass. MOVE QUICKLY TO STEP 5..... STEP FIVE - Before the liquid begins to collect into large areas and before any drying takes place, immediately begin wiping the quadrant just soaked with KLEENEX tissue to dry it....to do this, you want to gently PULL the Kleenex across the surface in ONE DIRECTION ONLY...do NOT go back and forth as this will streak and will tear the tissue into endless amounts of clumps that will have to be removed from the surface. You will see the liquid rapidly drying behind you. Follow each swipe IMMEDIATELY with a DRY Kleenex tissue. [reminder: keep changing to a dry tissue constantly!!] STEP SIX - When entire quadrant is reasonably dry, buff gently with a totally dry Kleenex; repeat a second time with another Kleenex while gently "puffing" a bit of your breath against the corrector plate or lens to expose possible areas of streaking. [reminder: keep changing to a dry tissue constantly!!] STEP SEVEN - Repeat same procedure on remaining three quadrants with a bit of overlap on each. [reminder: keep changing to a dry tissue constantly!!] STEP EIGHT - Check each point where areas overlapped during cleaning and "touch up" using a fresh Synthetic Cotton Replacement Pad sprayed with a VERY SMALL amount of cleaner....you want this swab nearly dry, but just enough moisture to touch up defects in cleaning. STEP NINE - Using your breath as a guide, gently "puff' against the glass while using a Synthetic Cotton Replacement Pad to buff the final cleaned surface to a high luster with not streaking! STEP TEN - [[OPTIONAL]] - USING THE RINSE SOLUTION This step is likely NOT necessary and should ONLY be used if there is any streaking left after the careful cleaning procedure outlined above. If there are problem areas, you should rinse your cleaned corrector/lens as follows: - spray a VERY SMALL amount of rinse solution onto the glass OR place some on a fresh Synthetic Cotton Replacement Pad.....you want only a tiny amount of liquid present to break the surface tension of the glass....remember, the glass is already cleaned from the CLEANING PROCEDURE. All you are attempting to do is to remove any streaks at this point. - gently rub the Synthetic Cotton Replacement Pad across the entire glass area quickly but very lightly and follow WITH YOUR OTHER HAND a fresh dry Kleenex tissue to absorb any moisture remaining from the first pass. This should take care of streaking very quickly. - again, buff the entire surface with a fresh and dry Synthetic Cotton Replacement Pad to finish. ------------------ Best of luck and take your time.....this solution and technique will work on all coated glass surfaces (NOT MIRRORS) and the solution is ideal as well for your binocular, eyepieces and camera lenses. The key to success is: 1) take your time; 2) work in small areas; 3) use LOTS of dry Kleenex; and, 4) use ONLY the materials and techniques described. Dr. Clay ---------------------------------------- Arkansas Sky Observatory www.arksky.org 6eda4db2ad8777a253870558ec84210c423761f0 0 226 299 2008-02-03T19:36:20Z Colin Kaminski 0 /* Beam Blocking */ wikitext text/x-wiki There is a great deal of equipment available for use in holography. While a hologram can be made with very simple equipment, many holographers have $1000s invested into there labs. The most important piece of equipment is the [[Laser]]. It privides the coherent light source required for making a hologram. In order to steer and shape the beam holographers use [[Mirror]]s, [[Lens]]es and [[Diffuser]]s. More advanced holography is done with 'split beams'. This involves taking the laser beam in splitting it into two or more beams with a [[Beam Splitter]]. A hologram is recorded on a medium. [[Silver Halide Film]] and [[Dichromated Gelatin Chemistry]] are the most common mediums for amature holographers and art holographs. Comercial holograms are usually [[Embossed Holograms]] or [[Polymer Film and Processes]]. Other exotic materials can record a holographic image. See [[Hologram Recording Materials]]. The stability of film is of the upmost importance to recording a hologram. [[Film Holder]]s are designed to hold film stable to 1/2 wavelength of light for the entire exposure time (or better). The polarization of a laser beam can be rotated with a [[Wave Plate]] and this can be quite useful in a large set up. Every optic will contribute noise to the laser beam. [[Optics Aberrations]], dust and fingerprints will leave a mark on the beam quality. In order to clean the beam a [[Spatial Filter]] is used. All of the optics past the first [[Beam Splitter]] need to be held perfectly still. This is acoumplished by designing a [[Optical Bench]] and [[Optic Mounts]] that are very rigid and have no resonances. The exposure time is calculated by using a [[Light Meter]]. Also the ratio of reference to object beam is measured with a [[Light Meter]]. In order to adjust the exposure energy a [[Shutter]] is used to turn the beam on and off. A [[shutter]] can be as simple as a black card removed from the beam by hand or a computer controlled device ===Fringe Lockers=== [[Fringe Locker]]s ===Beam Blocking=== [[Beam Blocker]]s ===Neutral Density Filter=== [[Neutral Density Filter]] 8c591686f5667a7ecebc5208297a21d7f5bec95c 0 446 1042 2008-02-04T01:26:05Z Colin Kaminski 0 wikitext text/x-wiki A '''neutral density filter''' or '''ND filter''' is a "grey" filter. An ideal neutral density filter reduces light of all wavelengths or colors equally. ND filters that are created by being partially reflective are often used in holography as a [[Beam Splitter]]. For an ND filter with 'OD' the amount of optical power transmitted through the filter is given by: Fractional Transmittance = 10^-OD In a graduated ND filter the intensity varies across the surface of the filter. Practical ND filters are not perfect as they do not reduce the intensity of all wavelengths equally. Most ND filters are only specified over the Visible spectrum region of the spectrum, and do not proportionally block all wavelengths of ultraviolet or infrared radiation. ND filters find applications in several high-precision laser experiments. This is because the power of a laser cannot be adjusted without changing other properties of the laser light](e.g collimation of the beam). Moreover, most lasers have a minimum power setting at which they can be operated. To achieve the desired light attenuation, one or more neutral density filters can be placed in the path of the beam. ND filters are quantified by their optical density or equivalently their f-Stop reduction as follows: {| border="1" cellspacing="0" cellpadding="5" align="center" ! Attenuation Factor ! Filter Optical Density ! f-Stop Reduction ! % transmittance |- | 2 | 0.3 | 1 | 50% |- | 4 | 0.6 | 2 | 25% |- | 8 | 0.9 | 3 | 12.5% |- | 64 | 1.8 | 6 | 1.5625% |- | 1,000 | 3.0 | 10 | <0.1% |- | 10,000 | 4.0 | 13 | <.01% |- | 1,000,000 | 6.0 | 20 | <.0001% |- |} Another practical way of determining what type of ND filter to use is by the percent of light that the filter allows to pass (transmittance). This parameter is typically applied to microscopy applications versus photography applications. Here is a more complete list of Filter Optical Density versus percent light transmitted: [http://www.chroma.com/images/noSpectra/22000a.gif] 7415c5480133dcd4b09349343092e0387605cb77 0 432 1014 2008-02-23T04:08:11Z Colin Kaminski 0 Resume change wikitext text/x-wiki [http://www.mbenyon.com Margaret Benyon's Website] [[Image:Mbenyon.gif]] Initially a painter, Margaret Benyon began to make holograms in 1968 when holography was available only to scientists. Her aim was to take holography out of the science lab, and to enlarge the boundaries of what was traditionally seen as fine art. Her early body of work with holography was an exploration of those aspects that were unique to it. Living in Australia with her partner and two small children in the 1970's led to work that was more humanist and cross-cultural. On returning to the UK in 1980 she began to use the human body exclusively, in a personal, partly therapeutic way. More recently she has been exploring the naturalisation of holography, and the female aesthetic. Her work with creative holography has been recognised with academic fellowships, artists' residencies, and a number of other art and holography related awards. She is currently listed in the International Who's Who, and in the millenium year she was awarded an MBE by HM the Queen in the New Year Honours List 2000 for services to art. Her work has been seen in a large number of exhibitions, in countries as far apart as the USA, Canada, Portugal, Italy, Australia, France, Germany, Japan, and China. Her works are in a number of public collections, including the Australian National Gallery and the Victoria and Albert Museum, London, and in an undocumented number of private collections world-wide. In 1994 she received a Ph.D. from the Royal College of Art, London, for her research and activities in art holography. Margaret Benyon made most of her holograms in her home studio on the south coast of England for 23 years. This was a basic, low-tech, non-commercial holographic studio, one of very few in existence. However, she also used more sophisticated international labs, and in 2005 moved to Sydney, Australia. She is currently an honorary Professorial Visiting Fellow at the College of Fine Art at the University of New South Wales, and continues to work internationally from Australia. 20b96fb2add961d59d6fccd5865f3ffb6498dacc 6 291 465 2008-02-24T01:21:31Z D.J. Mathson 0 Image from Sam´s Laserfaq http://www.laserfaq.org/sam/c532cav1.jpg wikitext text/x-wiki Image from Sam´s Laserfaq http://www.laserfaq.org/sam/c532cav1.jpg b88b4c2de2f083995b26aaee93f48a2ae396e19d 0 578 1306 2008-02-24T01:26:50Z D.J. Mathson 0 wikitext text/x-wiki There are many kinds of laser that have been used to make holograms. Below is a list of the most common types. ==HeNe Lasers== [[Image:HeNeLaser.jpg]] HeNe lasers were the most common laser used in amateur holography until the advent of the diode lasers. The are still often used because they have are inexpensive, have reasonable coherence length and the color is highly suited to available recording materials. A HeNe laser is a glass tube filled with Helium and Neon at about 5 Torr of pressure. There are electrodes placed inside the glass tube and a high voltage is passed between the electrodes. This causes the gas to glow like a neon sign. A mirror is placed at each end. They are usually reflective at 633nm (orange). One mirror is almost 100% reflective and makes the back of the cavity. It is called the HR (Highly Reflective) mirror. The other mirror makes the output side of the cavity and is called the OC (Output Coupler). Some HeNe lasers have mirrors that are external to the glass tube and some have mirrors bonded into the glass tube. With external mirrors, the ends of the tube can be fashioned to the [[Brewster's Angle]] and then the laser will have a [[Polarization|Polarized]] output. HeNe lasers are commonly available from .5mw to 50mw in output power. They are often TEM00. They can be polarized 100 to 1 and have a coherence length of a few inches without an [[etalon]]. Some large HeNe lasers are designed to accept an [[etalon]] and can have coherence lengths measured in meters. While a HeNe laser has about 20,000 hours of expected lifetime there are many modes of failure: *As electrodes age they start to give of metal that gets deposited inside the laser tube. When this contaminates the mirrors or the ends of the tube in an external mirror the laser starts to drop in power. This deposition can often be seen as a black deposit inside the tube and signifies the aging of the laser. *Seals inside the tube can start to leak and allow air to leak in. *The high voltage power supply can also fail. The power supply for a large HeNe can deliver 8ma at 6,000 volts! When servicing a HeNe laser it is very imortant that you understand the safety of the high voltage power supply. See [[Laser Safety]] for more information. [http://www.repairfaq.org/sam/laserhen.htm#hentoc HeNe Lasers at Sam's Laser FAQ] [http://en.wikipedia.org/wiki/HeNe HeNe Lasers At Wikipedia] ==Diode Lasers== Diode Laser are the fastest growing market of lasers. They have become inexpensive because they are used id CD/DVD reading and writing technologies. Red laser pointers contain a laser diode and most can be used for holography (as can most <5mw red diodes). [[Image:Ldpic.jpg]] This image shows the small diode chip resting on the housing with a blob of solder where the wire was attached. A diode laser is an interesting beast for holography. It has long coherence length but the frequency dependence on temperature is extremely critical. From Tom B. As a first approximation, coherence length = (wavelength ^ 2) / (2 * linewidth) e.g. for 670 nm center wavelength and line width (wavelength range) of 0.2 nm, coherence length = (670 * 10E-9)^2 / 2*(0.2E-9) = 0.0011 meter Exact value would depend on the shape of the line. The frequency equivalent:coherence length = speed of light / bandwidth e.g. for 1500 MHz, this is 3E8 / 1500E6 = 0.2 meter. (Iovine's book had a typo in this equation, but his example was correct) Math and example from Iovine, "Homemade Holograms", 1990. The rule of thumb for the temperature dependence of a visible single mode diode is .3nm/degree C. (Recently it was pointed out to me that visible laser diodes can have a slope of .18nm/C.) Fortunately this is not a continuous function. Otherwise we would need to hold a diode stable to within .00003C for a 20M coherence length! In-between mode hops the slope is much flatter. But even if it is .01nm/C in-between mode hops that works to a needed stability of .001C for a 20M coherence length. From my experience I can propose a rough guess of .05nm/C for inbetween mode hops. Soldering to a diode takes some practice if your are not an experienced electric technition. See [[Soldering to Laser Diodes]] for some tips The output of a diode laser is usually elliptical and you can use optics to circularize them. See the article [[Circularize an Elliptical Laser Beam]]. For useful background info on operating diode lasers, see the [http://www.ilxlightwave.com/navpgs/app-tech-notes-white-papers.html ILX application notes]. ===Stabilizing a High Power Laser Diode=== It is possible to stabilize the temperature of a laser diode with relatively simple setups. The necessary components are: A collimator that fits into a aluminum housing with at least one flat surface, a Peltier element, a cooling fin, a constant current power supply and a PI (Proportional Integrating) temperature controller. All parts are quite inexpensive and can be bought through the Internet. One such setup is as follows: [[Image:Stable_Laser1.jpg]] # Aluminum block with hole drilled to tightly contain the laser colimator housing+lens. # Laser collimator housing + lens + laser diode. # Aluminum base plate, several mm thick. If you make the base plate slightly larger, as is depicted here, enough space is left in front of the laser for other cool optical components, such as polarizers or an ECDL setup. Determine the amount of extra free space by turning on the diode with the collimator lens removed. The base plate should not block any light of the laser. The setup works great for Denisyuks when the lens is removed. # In a little hole that is drilled, a NTC must be embedded in the base plate. Because, for some reason known only by the gods of microelectronics, NTC resistors have no flat sides, the NTC resistor needs to be fixed tightly against the Peltier element on the other side of the hole with a thermally conducting epoxy. # The peltier element. Don't be tempted to try to control the temperature with a heating element instead of a Peltier. The PI controller will not be able to keep the temperature as constant with heating only. # A cooling fin to remove heat that is transferred by the Peltier element from the base plate when in cooling mode. Now for the power supply (from SAM's Laser FAQ): [[Image:Laser_Diode_Power_Source1.jpg ]] The only adaptation from the schematic shown in Sam's Laser FAQ is the 1 Ohm series resistor. The measured voltage over this resistor equals the current that flows through it (beats the heck out of removing the diode connectors and measuring the actual current with a multimeter in series with the diode). The LM317 was originally designed for constant Voltage power supplies, but with the little trick in this circuit it works as a very stable constant current source for less than a few dollars. The LM317 has been designed to keep the Volage at a constant 1.25V between the middle and right terminal. Because the two terminals are connected with the two resistors in-between, it is the value of these two resistors (V=I*R) that determine the current that comes out of the right-hand terminal. Only a few nA will flow back into the middle terminal, the rest goes into the diode. The power supply to this constant current source needs to be stable and a few volts above the Voltage that is consumed by the laser diode. The capacitors can be cheap metal film capacitors, but preferrably not electrolytic caps. How to hook it all up together: [[Image:Top_View1.jpg]] It is important to note that all components need to make good thermal contact in this setup. I have used thermal conducting epoxy for gluing all components together. When using a good PI controller (such as the HTC1500 or HTC3000 + evaluation board), it is possible to keep the temperature of this setup within 0.001C. Holograms look deep and sharp, and no visible mode hops when a diode current or temperature is chosen where the diode output is stable. [[Image:Temp_Controlled_Diode_Laser.JPG ]] Here is how I use the laser when it is in "Denisyuk mode" (collimator lens removed). It works every time with about 1 minute of warmup time and have not seen a single mode hop since. To the right the temperature PI controller can be seen. This is a HTC3000 with evaluation board. It needs to be powered with a power supply that can supply at least 4A, at about 9V. I do advise to use an evaluation board when you purchase a PI controller because they come with all the switches and trimmer pots to make the system almost plug and play. Sources for parts: 50mW HL6512MG laser diode (tested in this setup): http://www.thorlabs.com Diode Housing + Collimating Optics: http://www.mi-lasers.com/cgi-bin/shopper.cgi?search=action&keywords=diode_optics TEC Controller + Evaluation Board: http://www.teamwavelength.com/products/product.asp?part=6 ==DPSS Lasers== [[Image:C532.200sm.jpg]] Above is a picture of a Coherent C532-200. A larger view is available [http://www.laserfaq.org/sam/c532cav1.jpg Here]. Images used with permission of [http://www.repairfaq.org/sam/lasersam.htm Laser Sam's FAQ]. This image shows that this laser is a ring laser. DPSS lasers use a 808nm laser diode to pump a 1064nm [[Nd:YAG]] laser, which uses an intra-cavity [[KTP]] crystal to double the frequency to 532nm. [[Nd:YVO4]] can also be used as the gain medium. It can be frequency doubled with [[BBO]] to 457nm or 532nm. Generic DPSS lasers, such as green pointers or cheap constructions, will in general not be useful for holography because they won't be single frequency lasers, which means they won't have a decent [[Equipment#Longitudinal_Modes_and_Coherence_Length|coherence length]]. Moreover, without active temperature control they won't be stable enough (exceptions may apply). As a rule, only DPSS lasers specifically built for single frequency operation are suitable. A commonly used example is the [http://www.coherentinc.com/Lasers/index.cfm?fuseaction=show.page&id=301 Compass 315M-100] laser with 100mW output, which, as well as its higher powered cousins, has a proven track record to be excellently suited for holography purposes. It is relatively easy to obtain from the surplus market, and typically goes for anywhere from $250 for a bare laser head to $1500 for a complete system including power supply. A common method for making a single frequency DPSS laser is a ring laser. A ring laser has a traveling wave where all of the light only goes in one direction. The single traveling wave is obtained by inserting a [[Faraday Rotator]] and a polarizer into the cavity. For more information see [[Ring Laser]]. *[http://en.wikipedia.org/wiki/Diode_pumped_solid_state_laser DPSS Lasers from WikiPedia] *Koechner, Walter (1992). Solid-State Laser Engineering, 3rd ed., Springer-Verlag. ISBN 0-387-53756-2 *A great description of DPSS ring lasers can be found in [http://www.holographyforum.org/files/holopdfs/DPSSThesis.pdf Christoph Boling's Thesis]. ==Argon Ion Lasers== These are the high-powered workhorses of many professional holographers. They can emit several wavelengths, the primary ones are 514nm (green), 488nm (cyan) and 476nm (blue). The power ranges typically from 10-20mW for small air-cooled types, to hundreds of mW and several Watts for large frame lasers. The power consumption tends to be enormous, even the smallest ones require approx 1kW to run, and the larger ones much more so they need to be water cooled. By far not all argon lasers are suitable for holography, and especially the air-cooled types easily available on the surplus market are problematic, because they often do not fulful some basic requirements as they are made for other purposes (eg as components of printing machines). The three basic requirements for an argon laser to be suitable for holography are: - single line operation: this means operation on only one of the lines 514nm, 488nm, 476nm, etc. This can be achieved either by using specific mirrors ("single line optics"), or by using an intracavity "Littrow" prism. The latter allows to quickly change the wavelength by simply tilting the prism. Small air cooled argon lasers, like the ones of Cyonics/JDS, Lasos, NEC, most often have internal mirror tubes, and so do not allow any changes. Other common types like the ALC 60 have external mirrors, but often have multi-line mirrors installed. Littrow prisms are mostly a feature of larger water cooled ion lasers made for research, eg from [http://www.coherent.com/Lasers/index.cfm?fuseaction=show.page&id=794&loc=834 Coherent], [http://www.lexellaser.com/laser_8595.htm Lexel], and Spectra Physics (now [http://www.newport.com/store/genproduct.aspx?id=368211&lang=1033&page=2 Newport]). - TEM00 mode operation: this is not always granted. For example, Lexel 88 lasers made for ophthalmic use do not have pure TEM00 mirrors installed by default; similar for ALC 60. - Single frequency (single [[Equipment#Longitudinal_Modes_and_Coherence_Length|longitudinal mode]]) operation: the gain bandwidth of an argon laser is typically in the order of 10Ghz, which means that generically many modes will lase simulaneously, unless prevented from doing so. 10Ghz corresponds to a length of a little more than an inch (3cm), so this translates to a [[Equipment#Longitudinal_Modes_and_Coherence_Length|coherence length]] of this order of magnitude. This means that the maximum recordable depth of a hologram will be only an inch or so. In order to prevent more than one mode to lase and thus to ensure single frequency operation, the method of choice is to use an intracavity [[etalon]]. This cannot be done, of course, for most common air cooled lasers with internal mirrors. Retrofitting a laser with external mirrors with an etalon requires a massive reconfiguration of the resonator, and works well only for an etalon that has been optimized for that laser. In short, it is by far the best option to acquire an argon laser that comes already with an [http://www.lexellaser.com/techinfo_features_single-freq_503-etalon.htm built-in etalon], anything else gives a lot of problems and most likely leads to unstable operation with low power. Air cooled argon lasers are also problematic due to excessive vibrations from the fan(s), and air currents and temperature gradients from the 1KW or more of dissipated heat. Taking everything together, air cooled ion lasers are not well suited for holography purposes, and given that their power is typically <100mW, a DPSS laser is definitely a better choice. On the other hand, water cooled ion lasers equipped with etalon and single line/single mode optics are perfectly suitable, and surplus ones tend to get cheaper all the time due to market competition with DPSS lasers; used small and mid frame used lasers typically go between $1000-$2500 including power supply. This is the Spectra Physics 165 Argon Ion water cooled three phase laser with the cover on. [[Image:LaserWCover.jpg]] This is the power supply for the Spectra Physic 165 Argon Ion water cooled three phase laser. [[Image:PowerSupply.jpg]] This is the rear of the laser. At the far left you can see the verical and horizontal adjustments. The horizontal changes wavelengths but the verical needs to be adjusted slightly when changing wavelengths. I usually move the vetical slightly toward the wall (back for blue) until the beam is dim to adjust the horizontal also back for blue. The opposite for green. Just to the right of the tuning belts you can see the air spaced etalon. It also has a vertical and horizontal adjustment. I adjust till peaked at flash point then move just the horizontal until the fringes are stable and contrasty. [[Image:WaveSelectAndEtalon.jpg]] This is the front. It has an adjustable aperture (dial with numbers on it) and a beam splitter to steal some light for the built in power meter on the power supply. It is barely noticable but on the right under the black square. The solenoid at the far left with the very fine tube is the refill solenoid which is used via the power supply to add addition argon gas when the tube voltage drops because of low argon gas. I usually have to do this once a year with my minimal usage. [[Image:FrontApertAndPowerMeter.jpg]] This is the entire laser looking from the rear. [[Image:WholeLaser.jpg]] ==Helium Cadmium Lasers== HeCd lasers operate at 441.6nm. They can be TEM00 with coherence lengths of around a few cm. ==Other CW Lasers== Krypton ion lasers are among the highest powered CW lasers in the yellow-red color range. For most aspects except wavelength, they are very similar to [[Types of Lasers#Argon Ion Lasers|Argon ion lasers]]. They are rarely available as surplus. ==Pulsed Lasers== [[Image:MOPA1.jpg]] A pulsed laser is one of the most exciting lasers to have for holography. It lowers the stability requirement by shortening the exposure time to the range of 20ns. The two lasers most often used are the Pulsed [[Ruby]] Laser and the Frequency doubled [[Nd:YAG]] or [[Nd:Glass]] lasers. These lasers have been very expensive. However, lately there has been work done converting the [[SSY-1]] [[Nd:YAG]] laser to work for holography. This may make pulsed holograms for around $1500 in cost. [[Ruby]] lasers work in the far red spectrum of 694nm and are difficult to see and often require special make up for portraiture work and pre-swelling of the plate. See [[Tips for Pulsed Ruby Holograms]]. Frequency Doubled Pulsed Lasers work in the 532nm wavelength of green and often require post-swelling of the plate to make the hologram color more golden but special makeup not required. Pulsed lasers for holography are usually a [[MOPA]] design in order to obtain enough power. [http://www.holographyforum.org/pulse RotorWave] had great notes on designing and building pulsed lasers. The Holography Forum has mirrored some of it's files. A more updated version may be available on Laser Sam's FAQ. Here is a page of [[Adam's SSY]]. This is a ruby pulsed laser frequency doubled for about $400! It is capable of small hollograms. 49a63f661d32ce95e2c5b065a7cacfff8a61f410 0 257 361 2008-03-12T15:09:36Z Paul Barefoot 0 wikitext text/x-wiki [[Image:HSilver.jpg]] Harriet Casdin-Silver is a pioneer of art holography in the United States and was an important figure in the development of installation art and technological art in the 1960s. Casdin-Silver’s work is internationally recognized and has been exhibited for over 25 years in museums, galleries, and universities through the Americas, Europe, and Asia. She has not only set aesthetic standards for holography but also stretched the scientific boundaries of the medium. Casdin-Silver was the first artist to develop frontal-projection holograms, the first to explore white light transmission multi-colored holograms, and the first to exhibit outdoor, solar-tracked holograms. Casdin-Silver began her artistic career in the 1960s as a painter and quickly moved into multi-media and technological images. In 1968, she made her first holograms, becoming one of the first artists to work in this media. Casdin-Silver’s early work focused on both abstract and object-based images; by the late 1970s, Casdin-Silver began exploring the human figure, in particular the female body. At the same time, the artist began to combine holography with other media to create installation pieces. More recently, Casdin-Silver’s work focuses on the issues of feminism, the human form, the aging process, death, and issues of identity. -- Nick Capasso, Curator, Harriet Casdin-Silver: The Art of Holography, a retrospective at the DeCordova Museum and Sculpture Park CASDIN-SILVER, American, artist; born Feb 10, 1925, died Mar 10, 2008. Education: University of Vermont, Burlington, Columbia University, New York, New School for Social Research, New York, Cambridge Goddard Graduate School, Cambridge. Career: Artist in residence, American Optical Research Laboratory, Framingham, Mass, 1968-73; Ukranian Institute of Physics, Kiev, 1989; Asst. Professor of Physics (Research), Brown University, Rhode Island, 1974-78; Fellow, Center for Advanced Visual Studies, MIT, 1976-85; Consultant, Rockefeller Foundation Arts Program, 1980-81; Visiting lecturer, Royal College of Art, London, 1992, also University of Ghent, Belgium; Prof., Mass College of Art and Design, Boston, 1999; Presenter, SKY ART Conf., Delphi & Ikaria, Greece, 2002; also independent artist Rockefeller Foundation Awards, 1978-79, 1980-82, Lifetime Achievement Award for Art In Holography (Univ. of Nottingham, UK), 1996, Visible Republic Award for public art, 2001, Shearwater Foundation Award for excellence in Holography, 1987, 2001. Exhibitions: Documenta6, Germany 1977, Vienna Biennale, Austria, 1979, São Paolo Bienal, Brazil, 1985, The Art of Holography (Retrospective), DeCordova Museum, USA, 1998, Celebration of Aging (audio-holographic installation), Boston 2000, Univ. of Rhode Island, 2001, Is Freedom Visible? Massachusetts Statehouse, 2002, Museum of Afro-American History, 2003, We Are Here, South Station Concourse, Boston, 2002. Publications include: My First 10 Years as Artist/Holographer, Leonardo, 1989, Holographic Installations, Sculpting With Light, Sculpture, 1991, "Putting Guts into the Machine", Women's Review of Books, 2004. Address: 99 Pond Ave. #403, Brookline, MA, 02445 (Home); 51 Melcher St., 5th Floor, Boston MA, 02210, USA (Studio). 849b9d41e88f4e2f06d4fca9f4138fa6ec5be16c 6 286 449 2008-03-12T15:43:07Z Paul Barefoot 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 456 1062 2008-03-12T17:02:32Z Paul Barefoot 0 wikitext text/x-wiki [[Image:Barefoot.jpg]] == ''Paul D. Barefoot'' == ''President:Holophile, Inc.'' Paul Barefoot saw his first hologram in New York at the International Center of Photography exhibition, ''Holography '75: The First Decade'', produced by Jody Burns and Posy Jackson. It was there that he caught "Holography Fever." Within months, he moved to New York from his hometown of Charlotte, NC, where he was Director of Marketing for a graphic arts company and a C130 pilot with the North Carolina National Guard. In November, 1975 he founded Holophile, Inc. to market holography to corporations and nonprofit clients. He also began an affiliation with John Bliss Associates, Inc. (later, Bliss, Barefoot & Associates, Inc.), who served as Public Relations counsel to the Museum of Holography from its inception in 1976. In 1977, Barefoot worked with Museum of Holography founder, Rosemary Jackson, to organize a traveling exhibition of the Museum's inaugural exhibition, ''Through the Looking Glass''. It opened in Toronto and traveled to art, science and children's museums throughout the U.S. Public response was overwhelmingly positive.The exhibition was booked with institutions continuously for ten years -- not returning to New York until its retirement in 1987. During that time, Barefoot took ''Looking Glass'' to Australia for an appearance at the Adelaide Festival of Arts, and to Jerusalem where it broke the all-time attendance record at the Israel Museum In1988, Barefoot began circulating the Museum's second traveling exhibition, ''FutureSight: Innovations in Art Holography''. This exhibition, curated by Rene Barilleaux, traveled to art museums and galleries in the U.S., plus a tour of four New Zealand museums in Auckland, Wellington, Christchurch and Dunedin. In 1992, Barefoot organized a new traveling exhibition entitled, ''The Nature of Holography''. A second show (of the same name) was developed in 1993 to meet the growing demand by art, science, and children's museums. A third exhibition, ''Holography: Making Faces'', was introduced in 2007. These exhibitions, which feature images from the Holophile Collection, are still in circulation. (See complete listing of host institutions since 1977 [http://www.holophile.com/html/exhibit.htm]) Since founding Holophile in 1975, Barefoot has worked as a producer of custom holograms for use by corporate, not-for-profit and government clients, including The American Gas Association, BP Oil de Venezuela S.A., Canary Islands Tourism Board, The Coca Cola Company, IBM, National Security Agency (NSA), M & T Chemicals, Inc., PricewaterhouseCoopers, Samsung Electronics, Pfizer Pharmaceuticals, Raytheon Canada, Ltd and The Weizmann Institute of Science. Barefoot continues to work in holography and other three-dimensional imaging technologies through his company, Holophile, Inc. ([http://www.holophile.com]), located in Killingworth, CT. e3695ac1ee3b828098db5f06e1b85e20e4577af6 0 258 363 2008-03-13T22:20:58Z Paul Barefoot 0 New page: == Hart Perry == During the last 30 years working as a filmmaker, Hart Perry has carved out three distinct reputations: social and music documentarian, cameraman and artist. In 1969 he w... wikitext text/x-wiki == Hart Perry == During the last 30 years working as a filmmaker, Hart Perry has carved out three distinct reputations: social and music documentarian, cameraman and artist. In 1969 he was the youngest cameraman at the legendary Woodstock music festival and in 1970 he directed his first music video, "Alice Cooper." In 1977, he was the principal cinematographer of the award-winning documentary "Harlan County, U.S.A." During the 1970s and 1980s, Perry was a innovative force in the development of holographic movies (Integral holographic stereograms). Working with a grant from the National Endowment for the Arts in 1977, he built the second optical printer for producing holographic movies in the world. As President of the Holographic Film Company (New York), he worked on commercial applications for holographic movies in the areas of advertising and portraiture. In addition, he was the Director of the Cabin Creek Center's Artist-in-Residence program, funded by the National Endowment for the Arts and the New York State Council on the Arts. This program represented the innovative collaborations of holographies with visual artists, sculptors and dancers. In creating holographic movies, Mr. Perry converted 16mm film footage to holographic film to capture both motion and dimension. The holographic film was then wrapped inside a Plexiglas cylinder and illuminated for viewing with a normal light bulb. This process was invented by Lloyd Cross in 1972. His holograms of computer generated images produced in the early 70s were innovative and have been widely exhibited in museums and art galleries. In addition, he produced holograms for Salvador Dali, Milton Glazer, Mabou Mimes, Agam and other artists. [http://www.perryfilms.com/hart.html] 775a4f686669bc313f7522671f2aa59579dcc242 0 423 996 2008-03-14T23:28:47Z Paul Barefoot 0 New page: == Lon Moore == Lon Moore was one of the first holographers to mass produce reflection holograms of popularized imagery. During the 1970s and 80s, he succeeded in experimenting with dif... wikitext text/x-wiki == Lon Moore == Lon Moore was one of the first holographers to mass produce reflection holograms of popularized imagery. During the 1970s and 80s, he succeeded in experimenting with different processing techniques, controlling the available colors produced by the predominantly monochromatic medium and using his chemical palette appropriately in each of his holograms. Moore was a director and instructor of the San Francisco School of Holography and has exhibited his work at numerous venues in the US and Canada. 441554dfb57afedc7d68bcf72dce2d822333f6fe 0 513 1176 2008-04-05T01:00:48Z Tommy Johnson 0 Added details to the how to adjust a spatial filter section wikitext text/x-wiki As per Newport. D = Fw/a D = Pinhole Diameter F = Objective lens focal length w = Wavelength of laser (sorry no Greek letter on my keyboard) a = Beam radius input to lens More.... http://www.newport.com/store/product.aspx?id=3873&Section=detail&lang=1# ====Positioning a Spatial Filter with a Collimating Mirror==== For a collimated reference beam you need to place the spatial filter the sum of the focal lengths of the objective and the mirror apart. The focal length of the mirror is the focal ratio times the diameter. A great seat of the pants method is to take a piece of poster board and trace the diameter of the mirror on it. Rough set the optics and then place the card so the beam is reflected on to the card from the spatial filter at the largest distance you can find. If it fills the circle drawn on the card then you have a collimated beam. If it is larger you need to move the spatial filter back. If it is smaller you need to move the spatial filter closer. This is all easier and quicker to do without the pinhole. ====Aligning a Spatial Filter==== This is just a stub. Please add if you can. Aligning a spatial filter is a very difficult task the first time you attempt it. Taking an hour or two is not unusual. After a few tries it is quite easy. *Remove the Pinhole and the Objective. *Put a card after the spatial filter, and put a small circle on it around where the beam hits it. *Replace the Objective, and align the body of the spatial filter so the laser hits the center of the objective, as well as making sure the large disk of light from the objective is centered on the mark on the card. *Center the X and Y adjustments on the pinhole (so you have as much "room to maneuver" as possible.) and set the Z adjustment so the Pinhole is far away from the objective. *Re-install the Pinhole, so that the small blob of light (it will be dim) which is making it through the Pinhole hits the circle on the card. (My spatial filter holds the pin hole onto the XY stage with a magnet, its location on the magnet is a course adjustment.) *Now imagine the hour-glass shape of the light, starting out wide immediately after the objective, narrowing down to the focal point, and then widening out to where the pinhole is. Right now, the pinhole should be approximately centered down stream from the focal point. The adjustment process will walk the Pinhole up the hour-glass till its right on the focal point. *Move the Pinhole a little bit towards the objective, and watch the blob on the card. If the blob stays centered as you get closer to the objective, keep adjusting it closer to the objective. If it moves off center, stop and tweak the X and Y adjustments to re-center the blob. *Note how the blob moves in the same direction as the X and Y adjustments. If you go too far towards the objective and pass the focal point, the X and Y adjustments will reverse direction. *Keep moving the Pinhole towards the Objective, recentering the blob as you go. As you get closer, the adjustments will get touchier and touchier. If you lose the blob, move the Pinhole away from the objective till it re-appears, re-center, and then continue from there. *At some point, as you get closer to the focal point, rings will become visible around the blob of light. Those are Arie rings from the laser diffracting off the edge of the Pin-hole, and a good sign. *Keep moving the pinhole closer (and tweeking the X and Y to keep the blob centered) until the Arie rings merge with the blob. The blob will start getting brighter very quickly as you get close. *When the Arie rings merge with the blob, you're done. *If the X and Y adjustments reverse directions you've over-shot, the Pinhole is between the focal point and the Objective. Move the Pinhole away from the Objective, and then continue from there, just like if you lose the blob. The adjustments will be large as you start, perhaps an entire turn of a thumb screw. As you get closer to the focal point, a 5 degree rotation may overshoot. ====Homebuilt Spatial Filters==== When building home made spatial filters it is good to consider the very fine threads from [[http://www.thorlabs.com Thor Labs]]. They have taps and pre-made inserts. The pre-made inserts are much easier to use. The 100 TPI screws only have a thread height of .006" and it is hard to drill a hole that smooth. If you need to the proper method is to drill the hole under-size and ream it to size with a straight reamer. *[[John Klayer's Spatial Filter Plan]] ====Color Holography==== The assumption is that you have combined the beams into a single path and you have telescopes on the beams before the beam combiners so you can control their diameters. (The further assumption that the divergence of the lasers is the same.) As we will see you don't want all of the beams to be the same diameter! Quote: From Edmund: 1.0 Beam Spot Diameter (microns) = (1.27 * l * f) / D where, l = wavelength of laser (microns) f = focal length of objective lens (mm) D = input beam diameter (mm) 2.0 Pinhole size is then determined for the table (see note): Pinhole Diameter (microns) = 1.5 * Beam Spot Size Diameter (microns) So we notice that wavelength makes a difference. For this example we will use the wavelengths of: 650nm 532nm 473nm In order to make white we need the beam spot diameters of all three beams to be equal. If we miss, the balance of white will be uneven radially from the center out. dspot=(1.27*.650*f)/D dspot=(1.27*.532*f)/D dspot=(1.27*.473*f)/D We will choose 8mm as the focal length of our objective in the spatial filter. dspot=(1.27*.650*8)/D dspot=(1.27*.532*8)/D dspot=(1.27*.473*8)/D dspot=6.604/D dspot=5.405/D dspot=4.806/D In order to allow more light through we multiply a correction factor of 1.5 to the calculated values. Pinhole=9.906/D Pinhole=8.108/D Pinhole=7.209/D Now we are using only one pinhole and we need three beam diameters to make three equal spot sizes. If our red laser is 10mm then we use a 10 micron pinhole. For green the beam needs to be 8.1 mm in diameter. The blue beam needs to be 7.2 mm. Now the last equation we need is a way to change the diameter of our laser beams. In order to make a beam larger (or smaller really) we need to understand a very simple equation. InputD/OutputD=fl1/fl2 when the lenses are at fl1+fl2 distance apart. So if our red laser is 10mm dia. And our Green laser is 5mm then we need a telescope in the path of the green laser in the ratio of 5 to 8. If the lenses we have access to are 50mm and 80mm focal length then we place them 130mm apart and in the path of the green beam before the beam combiner. Now for example if the blue laser is 2.5mm we need to be 2.5 to 7.2 ratio and we could choose 25mm and 75mm focal length lenses placed 100mm apart. Now when we combine the beam we get a true Gaussian white beam. When we pass them through the spatial filter we have a white Gaussian spot with no color variation across the beam diameter. Note these same equations can be used to [[Circularize an Elliptical Laser Beam]] using cylindrical lenses. For reference: http://www.edmundoptics.com/techsupport/DisplayArticle.cfm?articleid=272 63f95f19ebac61f77fcbf44ce4400445699cbeaa 0 270 387 2008-04-22T17:43:04Z John Pecora 0 wikitext text/x-wiki [[Image:CIEDiagram.jpg]] Holograms need a material to record interference fringes. There are many materials that can record fringes. '''[[Silver Halide Chemistry]].''' Theory and Practice of Making Silver Halide Plates and Development. '''[[Silver Film Comparison Chart]]''' A quick comparison of the qualities of different commercially made films. '''[[Dichromated Gelatin Chemistry]].''' Theory and Practice of DCG Plates and Development. '''[[Polymer Film and Processes]]'''. Many commercially sold holograms are made from photopolymers. '''[[Photoresist]]'''. Taken from the electronics industry, this material can make relief holograms for embossing. '''[[Coating Methods]]'''. Coating Gelatin on to a glass plate is an art in itself. '''[[Crystals]]'''. There are many crystals that can record an image. The cost and exposure energy required is very high so they are not often used for holography. '''[[Embossed Holograms]]'''. These are like the holograms seen on credit cards. '''[[Gelatin]]'''. Used as the suspension medium to hold light sensitive particles. [http://en.wikipedia.org/wiki/Hologram#Materials Wikipedia's summary of Holographic Recording Materials] [http://en.wikipedia.org/wiki/Periodic_table_%28standard%29 Periodic Chart of the Elements] '''[[Books]]''' 155e35968057a437052d49b3dc62bd4bc0c9f685 0 491 1132 2008-04-22T18:06:52Z John Pecora 0 wikitext text/x-wiki DCG holograms are very sensitive to re-adsorbing moisture. If a hologram disappears after bieng in humidity you can usually get the image back by reprossing the hologram in alcohol drying baths. If you want to make sure the hologram is permanent you will need to seal the back side. The two most common methods are to seal the back with a glass plate or to coat the back with a cyanoacrilate adhesive. Most art holographers use the glass plate method. == Glass Plate Method 1 - Full Coverage (UV Epoxy) == When sealing a hologram with the glass plate method it is important to scrape at least 3mm of gelatine off the edge all the way around the hologram. This insures that the edge of the gelatin is sealed. Once this is done the epoxy is spread evenly over the entire emulsion and a glass plate is place over the sealant. The entire sandwich is place over or under a UV light (black light) to cure. This sealant is bought to have the same index of refraction of glass and should dry clear. This sealant can be expensive. If you wish to make your own UV sealant see Jeff Blyths "Do It Yourself" UV sealant below. == Glass Plate Method 2 - O-Ring (Standard Epoxy) == An ecconomical approach that works very well is to use 5 minute two part epoxy (at any hardware store). Scrape 3mm of gelatin off the edge all the way around as indicated above as best as you can. Clean the glass cover plate. Mix the two parts of the two part epoxy as directed on the epoxy label. I use a q-tip cut in half and a piece of scrap glass. Once the epoxy is mixed use a tool, like the q-tip rod to evenly spread a bead of epoxy around the scraped 3mm area on the hologram. Place the cover plate on and insure there are no place missing any epoxy by visually inspecting it. Place on level surface and let dry. '''Here is a post from Jeff Blythe on making UV cure epoxy at home:''' ===A DIY UV sealant=== In keeping with the grand DIY philosophy of the Forum I thought I would put down some basic ingredients for making your own out of materials which are fundamentally cheap because of their big industrial use. However before that a hypothesis that fits observations I have made. I believe that the reason DCG has been so notoriously difficult to seal up and prevent moisture getting in is not necessarily due to any fault of hydrophobic glues being somehow rather more moisture pervious than expected. I believe the real trouble has been that sandwiched between 2 glass sheets the gelatin layer contracts with age and builds up a significant vacuum. This results eventually in outside air getting through microcracks inspite of diligently thick glue having been applied around the edges of the sandwich.. This contraction effect might be just to do with the basic properties of the gelatin under prolonged lighting but it could well be more to do with the final stubborn traces of water /alcohol still hanging about and alcohol vapour can very gradually (we can be talking “years” here) make its way through the edge sealant increasing the vacuum effect. Anyway whatever the cause an obvious way to minimise it is to put the newly processed DCG in a really dry warmer I am not sure what temperature is best but 60-70C for as long 24 hours seems to work or alternatively I have left them in a really effective desiccator for a week. Then without giving the ultra dry DCG a chance to re-absorb ambient humidity a dry glass cover plate with dry sealant can be put on. This topic has been discussed on the forum before and some of you guys have had vastly more experience than me at sealing. To make a UV curable sealant,you need a monomer, crosslinker, and free radical generator for UV. Monomer : Methyl methacrylate or better (more hydrophobic) is butyl methacrylate (NB. Not tert-butyl methacrylate) Crosslinker: Ethylene dimethacrylate (alternative silly name by Sigma Aldrich is ethylene glycol dimethacrylate). UV sensitizer (free radical generator in UV.): DMPA or dimethoxyphenyl acetophenone. One can use about 1 part DMPA to 100 parts monomer to 5-10 parts crosslinker. It gets harder the more crosslinker you add of course. (~80-100% crosslinker just cracks up). But the mix has initially a rather low viscosity , lower than the commercial stuff. It is a good idea to store mixture over silica gel in a fridge in the dark. Jeff 04551d1a55302ad8c0ac37991d9f6fb8e031cd24 0 571 1292 2008-04-24T17:37:48Z John Pecora 0 wikitext text/x-wiki ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and Dichromated Gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300nm long and 1.5nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape(2,3,4,5,19). If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties(6,7). These two images were taken from source (16). [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion(6,8,9). Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions(13,14). Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom(13,14). This image was taken from source (16). [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them(10,12). Research is needed using vitamin C with CrVI(11). ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII (15). During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram(15). The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://en.wikipedia.org/wiki/Collagen # http://www.britannica.com/eb/article-72553/protein # http://www.lsbu.ac.uk/water/hygel.html # http://www.stanford.edu/~spark7/ # http://en.wikipedia.org/wiki/Gelatin # http://www.lsbu.ac.uk/water/hygel.html # http://albumen.stanford.edu/library/c20/kozlov1983.html # http://www.greatlakesgelatin.com/gelatin%20information.htm # http://www.cdc.gov/niosh/topics/hexchrom/ # http://en.wikipedia.org/wiki/Hexavalent_chromium # http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/ # http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf # http://www.gelatin-gmia.com/index.htm # Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora # http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html # http://sandwalk.blogspot.com/2007/02/collagen.html d8a58ace23ab9b4c17938f8195ba69b3c28a8a22 0 576 1302 2008-06-28T00:23:33Z Colin Kaminski 0 wikitext text/x-wiki '''Correcting Milky Holograms''' Milkiness is caused by the film being too soft. There are many ways of fixing this problem (making the emulsion harder) but increasing exposure is not the best way. It sounds as if the gelatin you are using is naturally soft. So let's look at some other ways to use your gelatin and get it harder. You could try any of these or combination of these with a shorter exposure time. 1. First, shorten your exposure let's say by half (10min). Then after the exposure hold the hologram in your hand by the edges and with the laser shutter open, hold the hologram in the laser light and keep moving it side to side. The idea is to get additional crosslinking and thus hardening without actually creating any more fringes. Do this for the remainder of time of your original exposure so do this for the 10 minutes you took off the original time. If you cut your exposure to 5 minutes then do this for 15 minutes. After some testing you may be able to cut this additional lighting time down. 2. After a shorter exposure, 5 or 10 minutes, and before processing put the hologram in a lab oven (do not contaminate your cooking oven) and bake it at about 120F (49C) for 3 to 5 minutes. It's best to have a piece of flat steel in the oven to lay the hologram on, so when you put the hologram in the oven, it heats up all at once. Then when you take the hologram out of the oven, place it on anther piece of flat steel to cool it evenly. 3. Prior to exposure do the above baking technique. Then let the hologram cool and stablize to ambient room temperature and humidy before shooting. 4. Decrease the amount of water in your homemade "Fixer" (pyrosulphate/alum/water 20g/4g/400ml) and increase your fixing time. You'll have to test the increased fixing time as you never stated how long you fix. With higher concentrated formula, you may not have to increase fixing time at all but a little testing will tell. If you get too long, greater then 2-3 minutes, then decrease water. It's best to keep fixing to about 1 - 2 minutes. Try 20g/4g/300ml. 5. Put a couple of drops of Glycerol (glycerine) in your original emulsion formula. This will help speed up dark reaction in those 24 hours which will essentially cause the film to be a little harder. 6. Age your plate in a very dry area for 2 maybe 3 days instead of 1 day. You could make a few plates and shorter expose a plate each day and see what happens as the plate ages. 68cecf17abb4f5d752095f0e5e6b52ab900f9a5c 0 577 1304 2008-06-28T10:24:48Z John Pecora 0 wikitext text/x-wiki ===Troubleshooting=== So you made a hologram! But it is either not perfect or not even visible. Don't despair. We all have made holograms that are blank or have issues. I am going to run down the list of mistakes I have uncovered. For tips on troubleshooting DCG specific problems see [[Troubleshooting DCG]]. For some tips on variables see [[DCG Variables]]. ====Image Missing==== Motion or improper developing. Card left in the object beam or reference beam after checking beam ratios. ====Image Missing parts==== If the object is missing parts then the object was in motion during exposure. If the film is missing views then that portion of the film was in motion. Air bubbles in the index matching fluid will cause this problem. ====Image "Drippy"==== This is caused by soft emulsions and/or excessive pressure during squeegeeing. ====Image Dim==== Under or over exposure. Motion of the bench or film. Beam ratios wrong. ====Image has Rainbow Lines==== Light entered the edge of the plate and bounced between the two surfaces. Make sure to block any light entering the edges of the plate during exposure and reconstruction. ====Image has Circular Patterns (Bull's eye)==== Dust under film when laminated to the backing plate before exposure. ====Reflection Hologram Blurry==== It is normal to only have 4 inches of usable depth. The actual depth is related to how narrow of a bandwidth you are using for reconstuction. If you are looking for greater depth adjust your development to narrow the reconstruction bandwidth. There will be a corresponding decrease in brightness. In an H2 set-up it can be the object beam was too bright. As measured at the film plane the object can not be brighter than the reference beam. ====Image has Black Lines on the Object==== Object moved slightly. [[Image:ObjectMove1.jpg]] As you can see the piece of paper under the kitty moved causing the large black lines. ====Entire Image has black lines on it==== Laser changed frequencies during exposure (mode hop) or is running in two lines. ====Image Flashes at Extreme Viewing Angles==== Laser beam was reflecting off something on the table and reaching the plate. It is important to card off any stray light from the beam. ====Image has Black Lines on the Plate.==== The plate was moving during exposure. ====Plate is Completely Dark==== Overexposed. Fogged film. ====Plate won't Turn Dark in the Developer.==== Underexposed. Old chemistry. Forgot to add part B for 2-part developer. ====Image Flashes Rainbows from a Specific Location==== This spot is too bright/overexposed. If the object is very shiny try spraying with a flatting spray. Flat clear lacquer works if you can't find flatting spray. Rotating the polarization of the object beam with a 1/2 waveplate can turn off shiny parts of the object. Use a polarizer rotated to coincide with the reference polarization to view the object illumination as you rotate the 1/2 waveplate. ====The image has black spots on the Emulsion==== This is called burnout and is most common in image planed H2 copies. It can be corrected by: # Composition, and pre-visualization of the location of the recording plane of the transfer (H2) within it, # Cighting of the scene when making the master (H1) so as to avoid the highlights near the intended transfer plane, # Possibly manipulating the polarization of the scene lighting to reduce the highlights, # Setting the beam ratio by measuring the "object" light in the transfer recording plane at the location of the burn spots (which are easy to find by placing a card in the plate holder) and with a detector about the same size as an average burn spot, # Using a beam ratio and exposure time that gives optimum performance at the location of the burns, and # Using a processing regime that doesn't shrink or swell the emulsion as a function of beam ratio or exposure intensity. ===Diagnosing the Problem=== Once you have identified the cause it is important to figure out exactly what corrective action will help. Motion This is one of the most common problems. To find out if you are stable it is useful to make an [[Interferometry#The_Michelson_Interferometer|Interferometer]]. ===Pictures of Defects=== [[Image:Drippy.jpg]] Here is a hologram that is "drippy" or has "rainbow lines". It was caused by laser light entering the edge of the plate during exposure. Either design your plateholder to block light entering the edges of the plate or tape the edge off with electrical tape. [[Image:Woodgrain.jpg]] This hologram shows "woodgrain". It is caused by the laser light reflecting back and forth from the front to the back of the plate. Make sure you have the corect polarization of the reference beam and make sure the reference angle is somewhere near 54 degrees (Brewsters Angle). [[Image:ObjectMovement2.jpg]] This hologram shows the difficulty of making a hologram of paper. Here the paper moved, either because it was not trapped tightly enough or because it was changing humidity durring exposure. [[Image:PlateMovement.jpg]] Here is a hologram showing plate movement. The dim spots do not change based on view point. [[Image:UnderExposed.jpg]] This hologram was underexposed. You can tell it is under exposed because it is dim and it is even dimmer at the edges where there was less light. If the edges were brighter then you would suspect over exposure. [[Image:BurnOut.jpg]] This hologram shows "Burn Out". The little finger is very reflective and was placed too close to the film plane. You can see the black smear above the finger tip. 9b362a138549ccd4c405172a4bd252026a1c7dee 0 573 1296 2008-06-30T23:43:59Z Colin Kaminski 0 /* ''Detecting the Emulsion Side of the Plate'' */ wikitext text/x-wiki ===''Pinhole Calculation''=== As per Newport. D = Fw/a , where D = Pinhole Diameter F = Objective lens focal length w = Wavelength of laser (sorry no greek letter on my keyboard) a = Beam radius at input to lens More.... [http://www.newport.com/store/product.aspx?id=3873&Section=detail&lang=1# "Newport Pinhole"] ===''Calculating Laser Power vs Film Requirement vs Exposure Time w/Sample''=== Joules = Watts x seconds thus 1 mW = 1mJ/1 second 1 inch = 2.54cm 1 square inch = 6.45cm^2 For a film requiring '''100 mJ per cm^2''' Plate length(2.54 cm) x width(2.54 cm) = '''6.45 cm^2''' Laser putting out 10mw = '''10mJ per second''' '''10mJ per second''' /'''6.45cm^2''' = 1.55mJ per cm^2 per second '''100mJ per cm^2'''/1.55mJ per cm^2 per second = 64.5 seconds This is just a basic starting point based on the film energy requirement. Adjustments need to be made for laser light losses, processing etc.... ===''Detecting the Emulsion Side of the Plate''=== Most of these can be tried with a used piece of film plate with the lights on for practice. Note: These tricks rely on the fact that only one side is gelatin; with the Fuji film both sides are gelatin. If you breathe on the plate, the side that does not fog will be the emulsion side (no condensation occurs on the emulsion side because the gelatin absorbs the moisture). (This does not work for the Fuji film as it has gelatin on both sides.) Look at the edge of the glass with a safelight - the cleanest (non-ragged) edge is the emulsion side. With a bit of practice you can detect the difference in the dark by rubbing your thumbnail along the edge. If all the plates are oriented the same way, you can label the box ''emulsion this side ->'' The two finger method: moisten your thumb and index finger and pinch them together a few times. Now do the same motion with the plate between them, and it should be easy to feel which side is the sticky emulsion side. ===''Got old plates?''=== I have stacks of failed plates. Do yourself a favor now that you have some scrap plates: Spray paint one of the ruined jobbies white and use that as a dummy plate when setting up. Both sides and the edges. You will find this very useful when it comes to carding off light that would otherwise enter the edges of the glass as well as for checking the quality of your reference beam. A clean white surface is also nice for making sure that you have no specular reflections from shiny places on your object(s)... 9c1bd633db1f6db02b455471735d8373e0d05614 0 212 271 2008-07-01T15:18:01Z DannyBee 0 wikitext text/x-wiki Dichromated Gelatin (DCG) is one of the brightest media for recording holograms. It is used in art as well as [[HOE]] fabrication. [[A Beginners Approach to DCG]] by John Pecora [[A Simple DCG Recipe]] [[G307 DCG Formula]] Increased overall sensitivity and to 514nm - 532nm [[MBDCG]] [[DCG Theory]] [[Sealing DCG Holograms]] [[The Mechanics of Gelatin and the DCG Process]] [[DCG Variables]] [[Coating Methods]] [[Troubleshooting DCG]] 151638f01f328b547127e6f3311d0750a3661be9 0 196 239 2008-08-05T13:22:52Z Stanislovas Zacharovas 0 wikitext text/x-wiki 1801 Thomas Young performs Double-slit experiment. 1881 Albert Michelson invents the interferometer. 1891 Lippmann photography developed. Natural color photography through the interference of light. 1900 Dennis Gabor born in Budapest. 1948-9 Dennis Gabor publishes the seminal papers on wavefront reconstruction and holography is born - but the laser is not yet available. 1960 Theodore Maiman makes the first visible-light ruby laser. 1962 Lieth & Upatnieks develop off-axis transmission holography based on side-scanning radar. 1962 Denisyuk produces the first white-light viewable hologram. 1965 First paper on holographic interferometry published by Powell & Stetson. 1967 DCG process developed for holography. 1967 Larry Siebert of the Conductron Corporation makes the first hologram of a person. 1967 World Book Encyclopedia published which includes the first mass-produced transmission hologram. 1968 White light (rainbow) transmission holography developed by Stephen Benton. 1970 Sandbox system developed by Pethick and Cross. 1971 San Francisco School of Holography opens. 1971 Dennis Gabor awarded the Nobel prize for holography. 1972 “Kiss” Integral hologram developed by Lloyd Cross. 1974 Hologram embossing developed. 1976 Museum of Holography opens in New York. 1979 Dennis Gabor died - London. 1983 First hologram appears on a credit card from MasterCard. 1984 National Geographic puts rainbow hologram of an eagle on their cover. 1985 National Geographic puts larger rainbow hologram of a skull of early man on their cover. 1988 National Geographic features a full-cover rainbow hologram of the world. 1988 Photopolymer film developed by Polaroid. Allows very bright reflection holograms to be mass produced. 1992 Museum of Holography in New York closes. 1993 MIT acquires complete collection of the Museum of Holography. 1999 Geola patents printers for color digital hologram printing with pulsed lasers. 2000 First digital color hologram produced by Geola with a pulsed RGB laser. 2003 Stephen Benton dies. 2005 Emmett Leith died. 2005 The first color portrait hologram shot at Geola with HoloCam equipment and printed with a digital RGB printer. 2006 Yuri Denysiuk died. 2008 Geola's digital holograms named i-Lumograms - Integrated Light Writings. References: *Saxby, Practical Holography, ISBN 0750309121 *Unterseher, et. al Holography Handbook, ISBN 0894960164 *http://www.holokits.com/a-teaching_holography.htm *http://www.holokits.com/a-make_holograms_p2.htm *http://www.holokits.com/a-Types_of_Holograms.htm *http://www.holophile.com/history.htm *http://www.holography.ru/histeng.htm *http://chem.ch.huji.ac.il/~eugeniik/history/lippmann.html *http://nobelprize.org/physics/laureates/1908/lippmann-bio.html *http://nobelprize.org/physics/laureates/1971/gabor-autobio.html *http://www.commonsensedirections.org/html/Adjunct%20Pages/Theodore%20Maiman.htm *http://people.deas.harvard.edu/~jones/ap216/lectures/ls_2/ls2_u5/ls2_unit_5.html *http://www.xmission.com/~ralcon/dcg-refs.html *http://www.jfairstein.com/SOH.html *http://web.media.mit.edu/~sab/ *http://nobelprize.org/physics/educational/laser/facts/index.html http://www.geola.lt/show.php?lang=eng&cont=holo_history&lside=holo_index_left (taken from A Consise History of Holography by [http://www.dragonseye.com/blog Michael Harrison], any errors are mine. Once I figure out how to add pictures I'll add the thumbnails that go along with the document - msh) 158d1870ac8693045e2a6862500bd90604396c1a 0 160 167 2008-08-06T14:05:03Z Colin Kaminski 0 wikitext text/x-wiki *BS - Beam Splitter *DE - Difraction Efficiency *DMD - Digital Micro-Mirror Device *EASLM - Electrically Addressed Spatial Light Modulation *H1 - A first generation hologram *H2 - A hologram of a hologram (copy) *H3 etc. - Sucessive generations of holograms *HOE - Holographic Optical Element *LASER - Light Amplification by Stimulated Emission of Radiation *l - liters *''l'' - length *LCD - Liquid Crystal Display *m - meters *''m'' - mass *M1, M2, M3 ect. - Mirror 1, Mirror 2, Mirror 3, etc. *mJ/cm^2 - milliJoules per centimeter squared *RH - Relative Humidity *SBR - Single Beam Reflection *SBT - Single Beam Transmission *SF - Spatial Filter *SI - International System of Units *SLM - Spatial Light Modulator *TEA *uJ/cm^2 - microJoules per centimeter squared *" - Inch = 25.4 mm *' - Foot = 12 inches Also see the [[Holography Glossary]]. ------------------------------------------------------------------------------ '''From Sergio on the Forum''' Some post recommendations internationally acept: SI writing style * Symbols do not have an appended period/full stop (.) unless at the end of a sentence. * Symbols are written in upright (Roman) type (m for metres, l for litres), so as to differentiate from the italic type used for variables (m for mass, l for length). By consensus of international standards bodies, this rule is applied independent of the font used for surrounding text.[10] * Symbols for units are written in lower case, except for symbols derived from the name of a person. For example, the unit of pressure is named after Blaise Pascal, so its symbol is written "Pa" whereas the unit itself is written "pascal". All symbols of prefixes larger than 103 (kilo) are also uppercase. o The one exception is the litre, whose original symbol "l" is unsuitably similar to the numeral "1" or the uppercase letter "i" (depending on the typeface used), at least in many English-speaking countries. The American National Institute of Standards and Technology recommends that "L" be used instead, a usage which is common in the US, Canada, Australia (but not elsewhere). This has been accepted as an alternative by the CGPM since 1979. The cursive ℓ is occasionally seen, especially in Japan and Greece, but this is not currently recommended by any standards body. For more information, see Litre. * The SI rule is that symbols of units are not pluralised, for example "25 kg" (not "25 kgs").[10] o The American National Institute of Standards and Technology has defined guidelines for American users of the SI.[11][12]These guidelines give guidance on pluralizing unit names: the plural is formed by using normal English grammar rules, for example, "henries" is the plural of "henry". The units lux, hertz, and siemens are exceptions from this rule: they remain the same in singular and plural. Note that this rule only applies to the full names of units, not to their symbols. * A space separates the number and the symbol, e.g. "2.21 kg", "7.3×102 m2", "22 K".[13][14] Exceptions are the symbols for plane angular degrees, minutes and seconds (°, ′ and ″), which are placed immediately after the number with no intervening space. * Spaces may be used as a thousands separator (1 000 000) in contrast to commas or periods (1,000,000 or 1.000.000) in order to reduce confusion resulting from the variation between these forms in different countries. In print, the space used for this purpose is typically narrower than that between words (commonly a thin space). * Any line break inside a number, inside a compound unit or between number and unit should be avoided, but if necessary the latter option should be used. * The 10th resolution of CGPM in 2003 declared that "the symbol for the decimal marker shall be either the point on the line or the comma on the line". In practice, the decimal point is used in English and the comma in most other European languages. * Symbols for derived units formed from multiple units by multiplication are joined with a space or centre dot (·), for example "N m" or "N·m".[15] * Symbols formed by division of two units are joined with a solidus (⁄), or given as a negative exponent. For example, the "metre per second" can be written "m/s", "m s−1", "m·s−1". Only one solidus should be used, i.e. "kg·m−1·s−2" is preferable to "kg/m/s²", and "kg/m·s²" is something else. Many computer users will type the / character provided on computer keyboards, which in turn produces the Unicode character U+002F, which is named solidus but is distinct from the Unicode solidus character, U+2044. * In Chinese, Japanese, and Korean language computing (CJK), some of the commonly used units, prefix-unit combinations, or unit-exponent combinations have been allocated predefined single characters taking up a full square. Unicode includes these in its CJK Compatibility and Letterlike Symbols subranges for back compatibility, without necessarily recommending future usage. * When writing dimensionless quantities, the terms 'ppb' (parts per billion) and 'ppt' (parts per trillion) are recognised as language-dependent terms since the value of billion and trillion can vary from language to language. SI therefore recommends avoiding these terms [1]. However, no alternative is suggested by the International Bureau of Weights and Measures (BIPM). d0e97b39c47c07f1e87a037dbbc69c4f0c89adf4 0 485 1120 2008-09-24T20:29:12Z Rudiefan 0 wikitext text/x-wiki [http://rudieberkhout.home.mindspring.com/home.htm Rudie Berkhout] Rudie Berkhout was a Artist/Holographer from Leeds NY. He had an extensive list of publications about holography and regularly exhibited his work. Born in Amsterdam, Berkhout came to the United States in 1974 with a background in engineering and lighting to study at the New York School of Holography. He later researched white light holographic techniques and pulsed holography at the New York Art Alliance laboratories. He created the first flat display system for holographic movies (Integral holography or holographic stereograms first developed by Lloyd Cross) while at the Holographic Film Company in New York (founded by cinematographer Hart Perry). Until this time, holographic stereograms had been viewed only in the round. Berkhout also designed and built a time-lapse recording system to enable artists to capture as much as four hours of movement in a single hologram. A major contribution to the medium was his work in color control and image multiplication which resulted in his breathtaking "Twelve Milliwatt Boogie" first exhibited in 1979 at the Museum of Holography, New York. This stunning piece set a standard in white-light transmission holography with its boldly-colored geometric figures floating in three-dimensional space. Rudie Berkhout passed away from a heart attack on Tuesday 16 September, 2008. 12495e5074373e7c65f22444dd5c9c44ed7bd6e4 0 180 207 2008-10-01T23:08:44Z Nini 0 /* Other Books */ wikitext text/x-wiki ==Must Haves== *Saxby, G., "Practical Holography" Third Edition, IOP, 2003, ISBN 0750309121. Reviews: [http://www.designerinlight.com/holo/graham.htm][http://www.dragonseye.com/blog/archives/17-Practical-Holography-3rd-Edition,-Graham-Saxby.html] *Unterseher, F., Hansen, J., Schlesing, B., "Holography Handbook", Ross Books, 1982, ISBN 0894960164. Reviews: [http://www.dragonseye.com/blog/archives/18-Holography-Handbook,-Unterseher,-et.-al.html] *Bjelkhagen, H., "Silver Halide Recording Materials for Holography", Springer-Verlag. 1996, ISBN 3540565760 *Hariharan, P., "Optical Holography", Cambridge University Press, 1996, ISBN 0521439655 *Keechner, W., "Solid State Laser Engineering", Springer, 1999, ISBN 3540650644 *DeFreitas, F., Rhody, A., Michael, S., "Shoebox Holography", Ross Books, 2000, ISBN 0894960601 ==Other Books== *Saleh, B., Teich, M., "Fundamentals of Photonics", John Wiley and Sons, 1991 *Jung, T. editor, "Holographic Imaging and Materials", Vol. 2043, SPIE, 1994 *Kock, W., "Engineering Applications of Lasers and Holography", Plenum Press, 1969 *Kasper, J., Feller, S., " The Complete Book of Holograms", John Wiley and Sons, 1987 *Cathey, W., "Optical Information Processing and Holography", John Wiley and Sons, 1974 *Brown, R., "Lasers: Tools of Modern Technology", Doubleday, 1968 *Jung, T. editor, "Practical Holography II", SPIE, 1987 *Iovine, J., "Homemade Holograms", Tab Books, 1990 *McGomb, G., "The Laser Cookbook", Tab Books, 1988 *Saxby, G., "Holograms", Focal Press, 1980 *Hecht, J., Teresi, D., " Lasers: Light of a Million Uses", Dover, 1998 *Horn, D., "Laser Experimenters Handbook", Tab Books, 1988 *Kock, W., "Lasers and Holography", Doubleday, 1981 *Ross, J., "3x8+1", Holograms 3-D, 1994 *Bergquist, C., "Laser Design Toolkit", Prompt Publications, 1999 *Smith, H., "Principles of Holography", Wiley, 1969 *Vacca, J., "Holograms and Holography", Charles River Media, 2001. Reviews: [http://www.dragonseye.com/blog/archives/19-Holograms-and-Holography-Vacca.html] *Gorglione, N. editor,"The Archives of Holography", Leonardo Vol. 25 No. 5, Pergamon Press, 1992 ==Holography Marketplace== *Ross, F., Yerkes, E., editors"Holography Marketplace: Second Edition", Ross Books, 1990 *Kluepfel, B., Ross, F., editors, "Holography Marketplace: Third Edition", Ross Books, 1991 *Kluepfel, B., Ross, F., editors, "Holography Marketplace: Fourth Edition", Ross Books, 1993 *Kluepfel, B., Rhody, A., Ross, F., editors, "Holography Marketplace: Fifth Edition", Ross Books, 1995 *Rhody, A., Ross, F., editors, "Holography Marketplace: Sixth Edition", Ross Books, 1997 *Rhody, A., Ross, F., editors, "Holography Marketplace: Seventh Edition", Ross Books, 1998 *Rhody, A., Ross, F., editors, "Holography Marketplace: Eigth Edition", Ross Books, 1999 ==Optics Books== *Popular Optics [[Popular Optics Review]] *Facets of Light [[Facets of Light Review]] *Seeing Light [[Seeing Light Review]] *Light Science [[Light Science Review]] 24deb9fc6bbd4df420e89da52eee5d14ede083e4 0 213 273 2008-10-02T21:58:27Z Nini 0 /* Split Beam Reflection */ wikitext text/x-wiki (For details and setup examples, see the [[Holography_Technology]] page.) (For a more technical description see [[Holograms]].) ===Comparison=== ===Single Beam Reflection=== Also called a Denisyuk Hologram this is the most common first hologram. It is fairly easy to set up and can be viewed in white light. This type of hologram is one of the least expensive as there are minimal optics and the stability requirement can be minimized by touching the plate to the object. ===Single Beam Transmission=== This is actually easier than a Single Beam Reflection however since it requires a laser for viewing it is not as common. The depth of field shown is often much better. This type of hologram is one of the least expensive as there are minimal optics and the stability requirements can be minimized. ===Split Beam Reflection=== This hologram is also known as an off-axis reflection hologram, or a "straight reflection" hologram. The laser beam is split into two beams with an partially mirrored beamsplitter, which can be mounted on a variable slide. One portion of the divided beam is spread with lenses or diffusion glass to illuminate the object, set in front of the holographic recording medium. The other portion of the laser is spread through a lens array or spacial filter, then reflected off of a collimating mirror, which is directed at the back of the hologram-to-be at the reference angle. The reference angle is determined by: practicality in the optical set-up; Bragg's angle and the frequency of the recording laser; and the angle of the intended viewing light; with a range of 38 to 46 degrees giving good interference fringes. The reference angle will become the illumination angle of view for the finished hologram. Steering mirrors are needed to complete this set-up. This type of hologram can be more expensive to produce as there are additional optics needed and more stringent stability requirements. It can be much brighter than a Single Beam Reflection. It can also contain relatively vast parallax. Depth is limited as in a Denisyuk hologram. (Image plane reflection holograms offer greater depth and projection possibilities, but their parallax potential is not as great as in a straight reflection hologram) ===Split Beam Transmission=== This is the most common way to make a transmission hologram. It requires a beamsplitter and is most often used to make an H1 for copying. This type of hologram is going to be more expensive as there are additional optics needed and more stringent stability requirements. ===H1 to H2 Copies=== This is making a copy of a hologram. It is a more complicated set up requiring a beamsplitter and a good Master Hologram (H1). It allows the hologram to bisect the film plane with some of the scene in front of the plate and some behind. ===Rainbow Transmission=== This is a special case of an H2 copy. It is a transmission hologram made by masking the master hologram (H1) to a horizonantal slit. It is viewable in white light but the color changes with viewing position. ===Multiplex=== This is a very complicated set-up and has to do with storing many close views or perspectives of an object onto a single holographic plate in the form of slits. Then those slits are imaged to the same relative location in space creating a focused, multi perspective image. A hologram is then made of the combined image projections creating 3 Dimension hologram. ===Holographic Optical Element (HOE)=== [[HOE]]s are holograms that work like optical elements (mirrors and lenses). ===Computer Generated=== By computing the interference patterns, it's possible to simulate a hologram in software. The result when printed to a transparency using a standard printer is usually low resolution and inefficient, but can work. [http://www.medcosm.com/prog_CGHmaker.htm MedCosm CGH Software (free)] 72613e8c79569859dab05e20926dd67cf1212570 0 419 988 2008-10-17T02:11:54Z Colin Kaminski 0 moved links to designerinlight.com wikitext text/x-wiki '''Papers on Lippmann Photography:''' Collected and Scanned by Martin. *[http://www.designerinlight.com/lippmann/Lippmann1891.pdf Lippmann CR 1891] *[http://www.designerinlight.com/lippmann/Lippmann1892.pdf Lippmann CR 1892] *[http://www.designerinlight.com/lippmann/Lippmann_photographie_Revue_scientifique_1884.pdf Lippmann photographie Revue scientifique 1894] - Scientific Revue Photographs *[http://www.designerinlight.com/lippmann/Usagin_engl.pdf English Translation of Usagin's 1902 article. Translated by Evgeniy Borozniak.] *[http://www.designerinlight.com/lippmann/Lippmann_On_Colour_Photography_1897.pdf Lippmann On Colour Photography by the Interferential Method], Proceedings of the Royal society of London,1897 *[http://www.designerinlight.com/lippmann/Presentation_de_Lippmann_Photographies_en_couleurs_du_spectre_negatives_par_transmission_1905.PDF Lippmann, Photographies en couleurs du spectre négative par transmission], Soc. Française de Physique, 1905 - Photographs colors of the spectrum negative by French transmission, Ploughshare of Physics *[http://www.designerinlight.com/lippmann/Lippmann_Photo_interferencielle_1906.PDF Lippmann Photo interférencielle CR 1906] - Interference Photographs *[http://www.designerinlight.com/lippmann/Lippmann_Des_divers_principes_sur_lesquels_on_peut_fonder_la_photographie_directe_des_couleurs_CR_1906_Tome_CXLIII.PDF Lippmann, Des divers principes sur lesquels on peut fonder la photographie directe des couleurs, CR 1906] Tome CXLIII - Various principles on which one can base the direct photography of the colors *[http://www.designerinlight.com/lippmann/Lippmann_Nobel_lecture_1908.pdf Lippmann, Nobel lecture 1908] *[http://www.designerinlight.com/lippmann/Becquerel_Sur_la_communication_de_M_Lippmann_1891.pdf Becquerel, Sur la communication de M. Lippmann, CR 1891] - On the communication of Mr. Lippmann *[http://www.designerinlight.com/lippmann/Ives_Present_condition_of_color_photography.pdf Ives Present condition of color photography, 1912] *[http://www.designerinlight.com/lippmann/Neuhauss_Paper.pdf Richard Neuhauss' Paper] Transcribed by Martin. *[http://www.designerinlight.com/lippmann/Labatut_Labsorption_et_la_photographie_des_couleurs_1891.pdf Labatut, L'absorption et la photographie des couleurs, CR 1891] - The absorption and the photography of the colors *[http://www.designerinlight.com/lippmann/La_decouverte_de_M_Lippmann_article_anonyme_1891.pdf Anonymous, La découverte de M. Lippmann, Les annales politiques et littéraires, 1891] - The discovery of Mr. Lippmann, political records and literary *[http://www.designerinlight.com/lippmann/Meslin_Sur_la_photographie_des_couleurs_1892.pdf Meslin Sur la photographie des couleurs, CR 1892] - Meslin On the photography of the colors *[http://www.designerinlight.com/lippmann/Meslin_Sur_les_interferences_prduites_1906.pdf Meslin, Sur les interférences prduites, CR 1906] - Meslin, On the interferences preduites *[http://www.designerinlight.com/lippmann/La_photographie_des_couleurs.pdf Ruckert, La photographie des couleurs, Paris 1900] - The photography of the colors *[http://www.designerinlight.com/lippmann/Presentation_de_Lippmann_Photographies_en_couleurs_du_spectre_negatives_par_transmission_1905.pdf Presentation de Lippmann Photographies en couleurs du spectre negatives par transmission 1905] *[http://www.designerinlight.com/lippmann/Presentation_de_Rothe_Photographies_en_couleurs_obtenues_par_la_methode_interferentielle_sans_mirioir_de_mercure_1904.pdf Présentation de Rothé, Photographies en couleurs obtenues par la méthode interférentielle, sans mirioir de mercure, CR 1904] - Photographs colors obtained by the interferential method, without mirror of mercury *[http://www.designerinlight.com/lippmann/Ponsot_Photo_interferentielle_et_polarisation.PDF Ponsot Photo interférentielle et polarisation, CR 1906] *[http://www.designerinlight.com/lippmann/Leroy_Preparation_et_sensitometrie_de_plaques_photographiques_a_grain.pdf Leroy, Préparation et sensitométrie de plaques photographiques à grain très fin, 1929] - Preparation and sensitometry of photographic plates with very fine grain *[http://www.designerinlight.com/lippmann/HBLippmannPhotography.pdf Bjelkhagen on Lippmann Photography] *[http://www.designerinlight.com/lippmann/An_experimental_study_of_the_Lippmann_color_photograph_1908.pdf An experimental study of the Lippmann color photograph 1908] by Herbert E. Ives. *[http://www.designerinlight.com/lippmann/Die_Farbenphotographie.pdf Die Farbenphotographie] by Neuhauss, 1898. *[http://www.designerinlight.com/lippmann/Die_Photographie_in_naturlichen_Farben.pdf Die Photographie in naturlichen Farben] by Eduard Valenta, 1912 *[http://www.designerinlight.com/lippmann/Die_Photographie_in_naturlichen_Farben.pdf Die Photographie in naturlichen Farben] by Maximimilan Engstler, 1904 *[http://www.designerinlight.com/lippmann/Extrait_de_La_photographie_et_la_photochimie.pdf Extrait de La photographie et la photochimie] by G.-H. Niewenglowski, 1897 *[http://www.designerinlight.com/lippmann/Innerer_Bau.pdf Innerer Bau] by F. Schütt, 1895 *[http://www.designerinlight.com/lippmann/La_photographie_des_couleurs.pdf La photographie des couleurs] by Alphonse Berget, 1901 *[http://www.designerinlight.com/lippmann/Lippmann_On_Colour_Photography_1897.pdf Lippmann_On_Colour_Photography_1897] *[http://www.designerinlight.com/lippmann/Lippmann_Photographies_en_couleurs_du_spectre_nogatives_par_transmission_1905.pdf Lippmann Photographies en couleurs du spectre nogatives par transmission 1905] has been published in the CR 1905. *[http://www.designerinlight.com/lippmann/Lippmann_Photo_interferencielle_1906.PDF Des divers principes sur lesquelles on peut fonder la photographie directe des couleurs, CR 1906] *[http://www.designerinlight.com/lippmann/Manuel_de_photochromie_interferentielle.pdf Manuel de photochromie interferentielle] by A. Berthier, 1895 [[Manual of Interfermetric Photography]] *[http://www.designerinlight.com/lippmann/Nachweis.pdf Nachweis] by R. Neuhauss, 1898 *[http://www.designerinlight.com/lippmann/Sur_la_theorie_de_la_photographie_des_couleurs_simples.pdf Sur la theorie de la photographie des couleurs simples] by Gabriel Lippmann *[http://www.designerinlight.com/lippmann/The_structure_of_Lippmann_heliochromes.pdf The structure of Lippmann heliochromes] by Santiago Ramón y Cajal, 1907 *[http://www.designerinlight.com/lippmann/Three_colour_interference_pictures_1907.pdf Three_colour_interference_pictures_1907] by Herbert E. Ives, 1907 *[http://www.designerinlight.com/lippmann/Traite_pratique.pdf Traite pratique] by G.-H. Niewenglowski, 1909 *[http://www.designerinlight.com/lippmann/Uber_die_Farbenwiedergabe.pdf Uber die Farbenwiedergabe] by Reinhold Aron, 1915 *[http://www.designerinlight.com/lippmann/uber_eine_neue_kornlose_Platte.pdf uber eine neue kornlose Platte] by Hans Lehmann, 1907 *[http://www.designerinlight.com/lippmann/Uber_ein_Badeverfahren.pdf Uber ein Badeverfahren] by Raphael E. Liesegang, 1915 *[http://www.designerinlight.com/lippmann/Ursache_und_Beseitigung_eines_Fehlers.pdf Ursache und Beseitigung eines Fehlers] by Otto Wiener, 1899 *[[Sogokon Article|Lippmann Photograph by Sogokon' A. B. ]] is reprinted from a Russian article originally scanned by Aleksandr. It was translated with Babble Fish and the translation was corrected and reformatted by Colin Kaminski. *[http://www.designerinlight.com/lippmann/Sogokon_Lipp_phot_on_DCG.pdf Englsh Translation of Sogokon's paper about Lippmann photography and DCG.] Translated by Evgeniy Borozniak. '''Integral photography:''' *[http://www.designerinlight.com/lippmann/Lippmann_Epreuves_reversibles_Photographies_integrales_1908.pdf Lippmann, Epreuves réversibles. Photographies intégrales, CR 1908] - Reversible tests. Integral photographs *[http://www.designerinlight.com/lippmann/Interview_avec_Lippmann_La_photographie_en_relief_est_trouvee_Je_sais_tout_No_037_42_1908.pdf Interview avec Lippmann, La photographie en relief est trouvée, Je sais tout, No 037-42, 1908] - Interview with Lippmann, photography in relief is found, I know all '''Other papers by Lippmann:''' *[http://www.designerinlight.com/lippmann/Lippmann_Sur_la_mesure_absolue_du_temps_deduite_des_lois_de_l_attraction_universelle_1899.pdf Lippmann, Sur la mesure absolue du temps, déduite des lois de l'attraction universelle, CR 1899] - To the absolute measure of time, deduced from the laws of the gravitation *[http://www.designerinlight.com/lippmann/Lippmann_Franges_d_interference_produites_par_le_systeme_de_deux_miroirs_perpendiculaires_entre_eux_1905.pdf Lippmann, Franges d'interférence produites par le système de deux miroirs perpendiculaires entre eux, CR 1905] - Interference rings produced by the system of two perpendicular mirrors between them *[http://www.designerinlight.com/lippmann/Lippmann_Appareil_pour_enregistrer_lacceleration_absolue_des_mouvements_sismiques_1909.pdf Lippmann, Appareil pour enregistrer l'accéleration absolue des mouvements sismiques, CR 1909] - Apparatus to record the absolute acceleration of the seismic movements *[http://www.designerinlight.com/lippmann/Lippmann_Methode_pour_le_reglage_d_une_lunette_en_autocollimation_1914.pdf Lippmann, Méthode pour le réglage d'une lunette en autocollimation, CR 1914] - Method for the adjustment of glasses in autocollimation *[http://www.designerinlight.com/lippmann/Lippmann_Sur_une_methode_photographique_directe_pour_la_determination_des_differences_de_Longitudes_1914.pdf Lippmann, Sur une méthode photographique directe pour la détermination des différences de longitudes, CR 1914] - On a direct photographic method for the determination of the differences in longitudes The file http://www.designerinlight.com/lippmann/Lippmann_Des_divers_principes_sur_lesquels_on_peut_fonder_la_photographie_directe_des_couleurs_CR_1906_T actually consists of two different papers by Lippmann: Des divers principes sur lesquelles on peut fonder la photographie directe des couleurs, CR 1906. That paper has actually nothing to with Lippmann photography but is related to yet another system for the recording of color photos. It's extremely interesting and based on color coding through transmission gratings. Principally, I guess it's the thing Kaveh did. Remarques générales sur la photographie interférentielle des couleurs, CR 1906. adc7586a658d7ac97921a73f365907b059788cfd 0 206 259 2008-11-25T18:26:41Z JohnFP 0 wikitext text/x-wiki == Here are variables and their effect on the DCG process == '''AmDi concentration''' - Lower redder less sensitive, higher bluer more sensitive '''Drying Temperature (Low ~20C)''' - Lower yields more triple helices, thus harder gelatin, clearer and more narrow band '''Drying Temperature (High ~30C)''' - Higher yields less triple helices, thus softer gelatin, less clear and more broadband '''Emulsion thickness''' - Thicker more narrow banded less light gets through, thinner more broadband '''Emulsion temp while mixing''' - Too low deforms on emulsion, too high pits, optimal centered at 120F '''Film freshness (film age)''' - Young broadband with milky tendeny, old narrow band and clear tendency '''Room Temp (exposure)''' - Warmer increased sensitivity '''Room Humidity (exposure)''' - More humid increased sensitivity '''Exposure Time''' - Longer harder bluer narrower banded, shorter softer redder broader banded '''Dark reaction time''' - Longer harder bluer narrower banded, shorter softer redder broader banded '''Fixer Time''' - Too short milky soft , too long harder bluer '''Light or heat fixing (if applicable)''' - Low light/heat softer broader banded milky, lots light harder bluer narrow band '''H2O rinse time''' - Too short non clear film '''H2O rinse temperature''' - Hotter broadband, lower narrow band '''IPA concentrations (ratios''') - Faster increase in ratios (35, 100) broadband, slow increase (30, 50, 70, 90, 100) narrower banded, modifying 50% from 35- 50% shifts color towards blue. '''IPA time''' - Shorter broadband, longer narrow band '''IPA temperature''' - Higher broadband, lower narrowband '''Blow drying''' - Too slow uneven blotches, to short degradation of holo over time '''Wavelength''' - The shorter wavlengths the higher sensitive, and will greatly effect the other variables 119bc19e660927aae15b70893617f3f082a94778 1632 260 2013-04-20T23:33:00Z Admin 0 Created page with "== Here are variables and their effect on the DCG process == *'''AmDi concentration''' - Lower redder less sensitive, higher bluer more sensitive *'''Drying Temperature (Low ~2…" wikitext text/x-wiki == Here are variables and their effect on the DCG process == *'''AmDi concentration''' - Lower redder less sensitive, higher bluer more sensitive *'''Drying Temperature (Low ~20C)''' - Lower yields more triple helices, thus harder gelatin, clearer and more narrow band *'''Drying Temperature (High ~30C)''' - Higher yields less triple helices, thus softer gelatin, less clear and more broadband *'''Emulsion thickness''' - Thicker more narrow banded less light gets through, thinner more broadband *'''Emulsion temp while mixing''' - Too low deforms on emulsion, too high pits, optimal centered at 120F *'''Film freshness (film age)''' - Young broadband with milky tendeny, old narrow band and clear tendency *'''Room Temp (exposure)''' - Warmer increased sensitivity *'''Room Humidity (exposure)''' - More humid increased sensitivity *'''Exposure Time''' - Longer harder bluer narrower banded, shorter softer redder broader banded *'''Dark reaction time''' - Longer harder bluer narrower banded, shorter softer redder broader banded *'''Fixer Time''' - Too short milky soft , too long harder bluer *'''Light or heat fixing (if applicable)''' - Low light/heat softer broader banded milky, lots light harder bluer narrow band *'''H2O rinse time''' - Too short non clear film *'''H2O rinse temperature''' - Hotter broadband, lower narrow band *'''IPA concentrations (ratios''') - Faster increase in ratios (35, 100) broadband, slow increase (30, 50, 70, 90, 100) narrower banded, modifying 50% from 35- 50% shifts color towards blue. *'''IPA time''' - Shorter broadband, longer narrow band *'''IPA temperature''' - Higher broadband, lower narrowband *'''Blow drying''' - Too slow uneven blotches, to short degradation of holo over time *'''Wavelength''' - The shorter wavlengths the higher sensitive, and will greatly effect the other variables. cee59ea6077f843b9025a25ea79d0a21d1e5dba6 0 207 261 2009-01-28T00:58:26Z Colin Kaminski 0 /* INTERESTING EXPERIMENTS TO TRY */ wikitext text/x-wiki Jeff Blyth has online instructions for making Silver Halide Plates. *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] ===Gelatin Film thickness=== In the case of MBDCG a thinner film can give a bit more sensitivity because you can have more MB dye in. If x % of dye is optimum for a dried film of 10 microns then for a dried film of say 40 microns you need to cut it down to 0.25x% and that is usually bad for sensitivity. If you leave it at x% then you kill too much object beam light. However you can get away with x% if you are able to do split beam reflection work (unlikely you have enough laser power with MBDCG unless you are making say 1 sq cm size images). Single beam transmission H’s could be OK though. ===Silver Halide=== If the diffusion method is tried on coatings much thicker than 7 microns it is troublesome. I have tried it on ~ 100 micron gelatin and decided that it was not viable. The problem being that the rate of diffusion decreases exponentially with time and AgNO3 can carry on diffusing into the thick film and away from the incoming bromide ions . If you leave it long enough (several minutes) for the bromide ions to catch up and combine with the furthest Ag ions near the glass then the front end may have already been in the Br bath too long and you start to get grain growth . If you don’t catch those unreacted Ag ions at the glass end then they quite rapidly develop up in the (ascorbic acid pH 6) sensitizer bath causing bad darkening or bad fog. You can stop this by giving the film a very prolonged soak in tap water (with its Cl- ions) after the Br bath before the sensitizer bath. What you get is then virtually all the silver bromide in the first few microns and none in the gelatin nearer to the glass , you might just as well have coated it thinner in the first place. However using the conventional process with AgBr precipitated in molten gelatin solution you still get fundamental problems if you try to coat ultra thick layers. The processing chemicals take much longer to migrate in and grain growth and unevenness is inevitable. I needed to make some experimental coatings about 1 mm thick and although I got gratings they were sadly dim. I struggled to get any grating at all. Once upon a time, Agfa produced an experimental 8E75’B’ coating that was twice as thick as usual but still only ~ 15 microns . Nobody found they could get a good result from it compared to their standard 7 micron. Jeff ===Hans' Diffusion Post=== As promised, here is a revision of Jeff Blyth's diffusion method that will allow you to make very bright holograms, and some theory as to why I think it works so well. When making your own holographic plates there are two requirements for bright results that work against one another: Lots of AgBr should be in the emulsion, and the AgBr crystals (grains) that are made up from all this AgBr should be as small as possible. It normally is very difficult to make an emulsion that complies to both these requirements and lots of articles have been written up about solving this problem. Lots of methods have been invented, but few are as reliable as Jeff's diffusion method. Why is it so difficult to make small grains: Imagine you have a gelatin solution into which you want to introduce AgBr grains. The traditional method would be to add to this gelatin solution a solution of AgNO3 and a solution of KBr. Both would be added at the same time at a certain rate. This method is called the double jet method. When the addition of the two solutions is started, at first nothing happens. Only the concentrations of both solutions slowly increase in the gelatin solution. Above a certain concentration, suddenly lots of Ag+ ions combine with lots of Br- ions to form very minute AgBr crystals. The formation of these crystals causes a fast decrease in concentration of both the AgNO3 and the KBr. As soon as the concentration drops below a certain value, any added AgNO3 + KBr will not create new grains (as we would like), but cause the grains that are already there to grow. This growing of the grains is not desirable. So, what I mean to say is that for new grains to form, the concentrations of the AgNO3 + KBr need to be above a certain critical value. Concentrations below this value cause grain growth and even lower concentrations do nothing at all. As you can see now the double jet method needs precisely controlled flows of liquids to allow for concentrations to be above this critical nucleation concentration to allow as many micrograins to form. Second problem is that if there are many small grains present, any newly added AgNO3+KBr prefers to settle onto those grains rather than forming new nuclei. And here lies the difficulty in making emulsions with both small grains and lots of grains at the same time. Most of the old recipes for making Lippmann emulsions are for making very fine grain emulsions, but with a very low amount of silver in them. Manufacturers of holographic film usually keep their methods for making their emulsions a secret just because of this reason. Now if there were a method of instant mixing a gelatin emulsion of very high concentration AgNO3 with a liquid of very high concentration of KBr (and very quickly after mixing both the excess AgNO3 and KBr could be removed), very small grains in high quantity would be virtually guaranteed. And this is where Jeff's brilliant diffusion strategy comes to the rescue: Imagine you had a very thin gelatin layer that was soaked with AgNO3 and this would be suddenly dunked into a solution of KBr, the KBr would be introduced to the AgNO3 throughout the surface of the gelatin as it diffuses into the layer. So a great many small grains of AgBr would form instantly everywhere inside the very thin layer of gelatin. If the layer is then quickly washed after this step, all excess AgNO3 and KBr are removed and thus further growing of the grains is no longer possible. This is not the whole story by a long shot though. In normal kitchen gelatin there are often left-over chemicals from the fabrication process that actually encourage grain growth. Any chlorides present in the gelatin would hamper the formation of small grains because AgCl is a lot more soluble than AgBr and also because when the AgNO3 is added to the gelatin, the first nuclei that are formed are AgCl nuclei and that's not what we want because we want the sudden process of virgin AgBr nucleation as the gelatin is dunked into the KBr solution. Any chemicals with Sulfides in them also cause grain growth. Luckily there is a way to clean your gelatin. More about this later. Just like there are chemicals that encourage grain growth, there are also chemicals that discourage grain growth. And that is where the second brilliant idea of Jeff comes to play. It just so happens that the dye used in the diffusion process (pinacyanol chloride) is one of those chemicals that help prevent grain growth. Adding this dye (that makes your emulsion sensitive to red laser light) to the KBr solution will help keep the grains small: as the gelatin is dunked into the KBr, the newly formed grains are quickly coated with dye molecules, preventing further settling of new AgBr onto them. One problem with the dye is that it does not like to be in water. That is why the KBr mixture is actually a mixture of water+methanol. The dye is very soluble of methanol and will stay even in solution if some water is present. Ok, so much for theory. Here is the procedure. Rather than writing up the differences from Jeff's original procedure I will now proceed and type the whole recipe. ====Washing the gelatin==== For this you need a small glass jar. Fill jar with 20ml of de-ionized (DI) water and add about 2.2 gram of gelatin. Next slowly warm this mixture to about 45C until the gelatin is completely dissolved. Take a plastic tupperware and pour this liquid into it and allow it to gel. When the solution has gelled, cut this gel up into small cubes with a plastic knife. Pour about 100ml of cold DI water into the tupperware tray, rock it a little and let it sit for about 30 minutes. (this step allows any contaminants in the gelatin to diffuse into the DI water). Pour off the DI water and add fresh DI water, rock and let it stand 30 minutes again. Repeat this procedure about 4 times. When you're done washing the gelatin, put it back into the glass jar and put it in the fridge (not the freezer) for later use. ====Preparing the glass==== When put into a alkaline developer, gelatin does not want to stick to glass anymore. So the glass needs to be prepared for holographic use. Firstly wash a piece of glass (say 20x30cm) with vinegar (this will remove some of the grease that is on the glass). After that, vigorously rub the glass with household ammonia and be very careful not to get any of this into your eye because it will make you blind forever. Now the glass will be very clean. The next step will be to chemically treat the glass to make it sticky. ====Making the glass sticky for gelatin==== Add about 0.5ml of 3-amino-propyltriethoxysilane (less is better than more) to 100ml of Acetone and rub this solution onto your cleaned glass plate. Let the plate sit for about one hour and then clean it again. This time with a Ammonia based glass cleaner. Your glass has now been coated with a very thin layer of molecules that on one side stick to the glass. The exposed sides of these silane molecules have -NH3+ endings that bond well with the gelatin. ====RainX==== You will need a second glass plate to be able to make a nice gelatin coating. Throughly clean a glass plate of the same size as the plate that was prepared from step [2] and rub it with an automotive anti rain agent such as Rain-X. And then rub it with a clean dry towel. On two opposing edges of this plate stick a long piece of Scotch tape. (During the coating step, gelatin will be poured onto this plate and the silane treated plate will be put on top of this gelatin puddle. The Scotch tape acts as a spacer and allows a perfect gelatin coating with just the right thickness when dried.) ====Preparing the chemicals==== * Mix 1g of pinacyanol chloride in 1000ml of methanol. This solution will last you a life time. * Mix 33ml of water with 66ml of Methanol. To this solution add 6 gram of LiBr and 2.5ml of the dye solution. Pour this liquid into a Tupperware tray that is big enough to hold your glass plate and close it. ====Wear Safety Glasses==== If you get AgNO3 in your eye you will be blind forever.:Take your washed gelatin from the fridge and warm it up to 45C again. When it has become completely liquid again, add 1.2 gram of AgNO3 to this solution. Often the solution becomes milky when you do this, but if you stir for about a minute, it will become transparent again. ====Coating the Plate==== Heat your Silane treated glass plate with a hair drier and while holding it level (USE KITCHEN GLOVES), pour a puddle of your gelatin on top of it. Quickly place the Rain-X treated glass plate on top of it and allow the gelatin to completely spread between the glass plates. After a few minutes the gelatin will gel and both plates will stick together. Now place this sandwich into the fridge and leave it there for a few hours. ====Washing Baths==== When doing the diffusion method it is important to stop the grain growth as soon as the grains are formed. Also it is preferable to remove any excess silver nitrate from the coating as soon as possible. So, prepare two trays of DI water to remove most of the AgNO3 and LiBr that is left over in the gelatin and one tray with tap water (most tap water contains some chloride that will precipitate with whatever Ag+ ions that are left after washing). To the tap water bath you should add a few drops of liquid dishwasher fluid. ====Diffusion Step==== After a few hours remove your glass sandwich from the fridge into your safe lighted room. With a plastic knife remove the Rain-X treated plate from your Silane treated plate. If all went well, the gelatin coating should stick to the Silane treated plate in a perfect smooth coating. Without waiting for the plate to dry or become warm, immediately drop this plate into the LiBr bath and leave it there for about 45 seconds. Then quickly take the plate out and transfer it to the first DI water bath for about 1 minute. Then the second DI water bath, then the tap water bath. Let the plate drip dry by setting it almost vertically against an object on your table. After about 15 minutes when most of the water has dripped from the plate you can use a cool hair drier to finish drying. ====Sensitizing==== Your freshly made plate will not be sensitive enough yet for practical use. Also the gamma of the emulsion will not be suitable yet for holography. Prepare a solution of 100ml water + 1.2 grams of Ascorbic Acid (=vitamin C) + 0.4 gram of NaCO3 + few drops of dishwasher liquid. Immerse your plate into this for about 2 minutes and dry again. When the plate is dry, it is ready for use and to be exposed for the brightest Denisyuk hologram you have ever made. Ok, so that's about it. It looks like a complicated and long procedure. But after you have done it a few times, you will find it easy and simple to do and reasonably fast. It is possible to make a number of plates in one day and store them in the fridge for later use. This procedure addresses a number of problems in the original procedure: * Lots more silver will be present in the gelatin. This will make your holograms a lot brighter. The original recipe calls for first coating the gelatin and afterwards introducing the AgNO3. This can certainly be done, but the gelatin needs to be very very hard and squeegeed well after adding the AgNO3. Otherwise AgNO3 will crystallize on the surface of the gelatin layer and prevent diffusion from taking place. * This method will allow for very soft gelatin layers to be made. This is interesting if you want to experiment in doing SHSG. * In the original method there is also some Ascorbic Acid in the LiBr+dye bath. This certainly does work, but you run the risk of developing out any AgNO3 that has not precipitated out. This causes some darkening of the plate. It is better to do the sensitizing afterwards. ====A SHORTCUT THAT IS ADVISABLE FOR FIRST TESTS==== * This adjustment will allow you to do the diffusion method very fast and still give the same brightness. * Skip steps [1] through [7] * Immerse a PFG-01 plate in a solution of 20% Sodium Thiosulfate (non hardening fixer) until it has become completely transparent. And rinse in DI water and dry. * Prepare a solution of 1 ml DI water + 0.18g AgNO3. * With a laser printer transparency spread a few drops of this solution over the surface of the fixed out plate and squeegie the plate very well. * Start from step 8 in the above procedure. * You have now upgraded your PFG-01 plate to a plate that competes well with the brightest plates in the world. I have done the original method, my adjusted method and the quicker method many times over and they give predictable results but have now switched to a completely different method (using double jet) that I don't want to write about just yet. ====INTERESTING EXPERIMENTS TO TRY==== *Gelatin at low concentration is much easier to coat than the 10% that is required for the above procedure. It would be interesting to try to make your fresh dry gelatin into a very fine powder in a kitchen slurpy mixer. Then load this fine powder in a very cold solution of AgNO3. The solution needs to be cold because otherwise the powder will become a sticky mass. Next run this mix through a coffee filter to drain off excess water+AgNO3. Then pour your LiBr+dye mixture over the powder that is still in the coffee filter (do catch what drips out of the filter because it can be used again). Next pour large amounts of DI water through the filter. If all liquids are rather cold during this procedure the gelatin will not clump up and it just might work. After this procedure you would have holographic gelatin that can dissolved when needed at concentrations of about 2% and coated by just pouring on a horizontal glass plate. I don't know if this procedure would work. But if it does work it would be very nice. I tried it once but made a mistake in the dark and made a mess of it. So I was not able to conclude if it is possible or not. *To coat a layer of 2% gelatin on glass to which some dichromate is added. Then make this layer really hard in an oven and use the shortcut method I wrote about above. The layer should be very smooth and hard enough to allow a good squeegee. I have not tried this, but if it works it will be a lot faster. Well, that's about all I know about the diffusion method. I very much enjoyed using it. Please understand that this is by no means the only way to do the diffusion method. If you want to have a go at it, try it this way first and then experiment with your own idea's. I am sure you will come up with idea's that will improve upon this method. 5fbf90e6847cc2d93b5cf5d99a86c8cdc0a705d4 1636 262 2013-04-20T23:50:47Z Admin 0 Created page with "Jeff Blyth has online instructions for making Silver Halide Plates. *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] ===Gelatin Fil…" wikitext text/x-wiki Jeff Blyth has online instructions for making Silver Halide Plates. *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] ===Gelatin Film thickness=== In the case of MBDCG a thinner film can give a bit more sensitivity because you can have more MB dye in. If x % of dye is optimum for a dried film of 10 microns then for a dried film of say 40 microns you need to cut it down to 0.25x% and that is usually bad for sensitivity. If you leave it at x% then you kill too much object beam light. However you can get away with x% if you are able to do split beam reflection work (unlikely you have enough laser power with MBDCG unless you are making say 1 sq cm size images). Single beam transmission H’s could be OK though. ===Silver Halide=== If the diffusion method is tried on coatings much thicker than 7 microns it is troublesome. I have tried it on ~ 100 micron gelatin and decided that it was not viable. The problem being that the rate of diffusion decreases exponentially with time and AgNO3 can carry on diffusing into the thick film and away from the incoming bromide ions . If you leave it long enough (several minutes) for the bromide ions to catch up and combine with the furthest Ag ions near the glass then the front end may have already been in the Br bath too long and you start to get grain growth . If you don’t catch those unreacted Ag ions at the glass end then they quite rapidly develop up in the (ascorbic acid pH 6) sensitizer bath causing bad darkening or bad fog. You can stop this by giving the film a very prolonged soak in tap water (with its Cl- ions) after the Br bath before the sensitizer bath. What you get is then virtually all the silver bromide in the first few microns and none in the gelatin nearer to the glass , you might just as well have coated it thinner in the first place. However using the conventional process with AgBr precipitated in molten gelatin solution you still get fundamental problems if you try to coat ultra thick layers. The processing chemicals take much longer to migrate in and grain growth and unevenness is inevitable. I needed to make some experimental coatings about 1 mm thick and although I got gratings they were sadly dim. I struggled to get any grating at all. Once upon a time, Agfa produced an experimental 8E75’B’ coating that was twice as thick as usual but still only ~ 15 microns . Nobody found they could get a good result from it compared to their standard 7 micron. Jeff ===Hans' Diffusion Post=== As promised, here is a revision of Jeff Blyth's diffusion method that will allow you to make very bright holograms, and some theory as to why I think it works so well. When making your own holographic plates there are two requirements for bright results that work against one another: Lots of AgBr should be in the emulsion, and the AgBr crystals (grains) that are made up from all this AgBr should be as small as possible. It normally is very difficult to make an emulsion that complies to both these requirements and lots of articles have been written up about solving this problem. Lots of methods have been invented, but few are as reliable as Jeff's diffusion method. Why is it so difficult to make small grains: Imagine you have a gelatin solution into which you want to introduce AgBr grains. The traditional method would be to add to this gelatin solution a solution of AgNO3 and a solution of KBr. Both would be added at the same time at a certain rate. This method is called the double jet method. When the addition of the two solutions is started, at first nothing happens. Only the concentrations of both solutions slowly increase in the gelatin solution. Above a certain concentration, suddenly lots of Ag+ ions combine with lots of Br- ions to form very minute AgBr crystals. The formation of these crystals causes a fast decrease in concentration of both the AgNO3 and the KBr. As soon as the concentration drops below a certain value, any added AgNO3 + KBr will not create new grains (as we would like), but cause the grains that are already there to grow. This growing of the grains is not desirable. So, what I mean to say is that for new grains to form, the concentrations of the AgNO3 + KBr need to be above a certain critical value. Concentrations below this value cause grain growth and even lower concentrations do nothing at all. As you can see now the double jet method needs precisely controlled flows of liquids to allow for concentrations to be above this critical nucleation concentration to allow as many micrograins to form. Second problem is that if there are many small grains present, any newly added AgNO3+KBr prefers to settle onto those grains rather than forming new nuclei. And here lies the difficulty in making emulsions with both small grains and lots of grains at the same time. Most of the old recipes for making Lippmann emulsions are for making very fine grain emulsions, but with a very low amount of silver in them. Manufacturers of holographic film usually keep their methods for making their emulsions a secret just because of this reason. Now if there were a method of instant mixing a gelatin emulsion of very high concentration AgNO3 with a liquid of very high concentration of KBr (and very quickly after mixing both the excess AgNO3 and KBr could be removed), very small grains in high quantity would be virtually guaranteed. And this is where Jeff's brilliant diffusion strategy comes to the rescue: Imagine you had a very thin gelatin layer that was soaked with AgNO3 and this would be suddenly dunked into a solution of KBr, the KBr would be introduced to the AgNO3 throughout the surface of the gelatin as it diffuses into the layer. So a great many small grains of AgBr would form instantly everywhere inside the very thin layer of gelatin. If the layer is then quickly washed after this step, all excess AgNO3 and KBr are removed and thus further growing of the grains is no longer possible. This is not the whole story by a long shot though. In normal kitchen gelatin there are often left-over chemicals from the fabrication process that actually encourage grain growth. Any chlorides present in the gelatin would hamper the formation of small grains because AgCl is a lot more soluble than AgBr and also because when the AgNO3 is added to the gelatin, the first nuclei that are formed are AgCl nuclei and that's not what we want because we want the sudden process of virgin AgBr nucleation as the gelatin is dunked into the KBr solution. Any chemicals with Sulfides in them also cause grain growth. Luckily there is a way to clean your gelatin. More about this later. Just like there are chemicals that encourage grain growth, there are also chemicals that discourage grain growth. And that is where the second brilliant idea of Jeff comes to play. It just so happens that the dye used in the diffusion process (pinacyanol chloride) is one of those chemicals that help prevent grain growth. Adding this dye (that makes your emulsion sensitive to red laser light) to the KBr solution will help keep the grains small: as the gelatin is dunked into the KBr, the newly formed grains are quickly coated with dye molecules, preventing further settling of new AgBr onto them. One problem with the dye is that it does not like to be in water. That is why the KBr mixture is actually a mixture of water+methanol. The dye is very soluble of methanol and will stay even in solution if some water is present. Ok, so much for theory. Here is the procedure. Rather than writing up the differences from Jeff's original procedure I will now proceed and type the whole recipe. ====Washing the gelatin==== For this you need a small glass jar. Fill jar with 20ml of de-ionized (DI) water and add about 2.2 gram of gelatin. Next slowly warm this mixture to about 45C until the gelatin is completely dissolved. Take a plastic tupperware and pour this liquid into it and allow it to gel. When the solution has gelled, cut this gel up into small cubes with a plastic knife. Pour about 100ml of cold DI water into the tupperware tray, rock it a little and let it sit for about 30 minutes. (this step allows any contaminants in the gelatin to diffuse into the DI water). Pour off the DI water and add fresh DI water, rock and let it stand 30 minutes again. Repeat this procedure about 4 times. When you're done washing the gelatin, put it back into the glass jar and put it in the fridge (not the freezer) for later use. ====Preparing the glass==== When put into a alkaline developer, gelatin does not want to stick to glass anymore. So the glass needs to be prepared for holographic use. Firstly wash a piece of glass (say 20x30cm) with vinegar (this will remove some of the grease that is on the glass). After that, vigorously rub the glass with household ammonia and be very careful not to get any of this into your eye because it will make you blind forever. Now the glass will be very clean. The next step will be to chemically treat the glass to make it sticky. ====Making the glass sticky for gelatin==== Add about 0.5ml of 3-amino-propyltriethoxysilane (less is better than more) to 100ml of Acetone and rub this solution onto your cleaned glass plate. Let the plate sit for about one hour and then clean it again. This time with a Ammonia based glass cleaner. Your glass has now been coated with a very thin layer of molecules that on one side stick to the glass. The exposed sides of these silane molecules have -NH3+ endings that bond well with the gelatin. ====RainX==== You will need a second glass plate to be able to make a nice gelatin coating. Throughly clean a glass plate of the same size as the plate that was prepared from step [2] and rub it with an automotive anti rain agent such as Rain-X. And then rub it with a clean dry towel. On two opposing edges of this plate stick a long piece of Scotch tape. (During the coating step, gelatin will be poured onto this plate and the silane treated plate will be put on top of this gelatin puddle. The Scotch tape acts as a spacer and allows a perfect gelatin coating with just the right thickness when dried.) ====Preparing the chemicals==== * Mix 1g of pinacyanol chloride in 1000ml of methanol. This solution will last you a life time. * Mix 33ml of water with 66ml of Methanol. To this solution add 6 gram of LiBr and 2.5ml of the dye solution. Pour this liquid into a Tupperware tray that is big enough to hold your glass plate and close it. ====Wear Safety Glasses==== If you get AgNO3 in your eye you will be blind forever.:Take your washed gelatin from the fridge and warm it up to 45C again. When it has become completely liquid again, add 1.2 gram of AgNO3 to this solution. Often the solution becomes milky when you do this, but if you stir for about a minute, it will become transparent again. ====Coating the Plate==== Heat your Silane treated glass plate with a hair drier and while holding it level (USE KITCHEN GLOVES), pour a puddle of your gelatin on top of it. Quickly place the Rain-X treated glass plate on top of it and allow the gelatin to completely spread between the glass plates. After a few minutes the gelatin will gel and both plates will stick together. Now place this sandwich into the fridge and leave it there for a few hours. ====Washing Baths==== When doing the diffusion method it is important to stop the grain growth as soon as the grains are formed. Also it is preferable to remove any excess silver nitrate from the coating as soon as possible. So, prepare two trays of DI water to remove most of the AgNO3 and LiBr that is left over in the gelatin and one tray with tap water (most tap water contains some chloride that will precipitate with whatever Ag+ ions that are left after washing). To the tap water bath you should add a few drops of liquid dishwasher fluid. ====Diffusion Step==== After a few hours remove your glass sandwich from the fridge into your safe lighted room. With a plastic knife remove the Rain-X treated plate from your Silane treated plate. If all went well, the gelatin coating should stick to the Silane treated plate in a perfect smooth coating. Without waiting for the plate to dry or become warm, immediately drop this plate into the LiBr bath and leave it there for about 45 seconds. Then quickly take the plate out and transfer it to the first DI water bath for about 1 minute. Then the second DI water bath, then the tap water bath. Let the plate drip dry by setting it almost vertically against an object on your table. After about 15 minutes when most of the water has dripped from the plate you can use a cool hair drier to finish drying. ====Sensitizing==== Your freshly made plate will not be sensitive enough yet for practical use. Also the gamma of the emulsion will not be suitable yet for holography. Prepare a solution of 100ml water + 1.2 grams of Ascorbic Acid (=vitamin C) + 0.4 gram of NaCO3 + few drops of dishwasher liquid. Immerse your plate into this for about 2 minutes and dry again. When the plate is dry, it is ready for use and to be exposed for the brightest Denisyuk hologram you have ever made. Ok, so that's about it. It looks like a complicated and long procedure. But after you have done it a few times, you will find it easy and simple to do and reasonably fast. It is possible to make a number of plates in one day and store them in the fridge for later use. This procedure addresses a number of problems in the original procedure: * Lots more silver will be present in the gelatin. This will make your holograms a lot brighter. The original recipe calls for first coating the gelatin and afterwards introducing the AgNO3. This can certainly be done, but the gelatin needs to be very very hard and squeegeed well after adding the AgNO3. Otherwise AgNO3 will crystallize on the surface of the gelatin layer and prevent diffusion from taking place. * This method will allow for very soft gelatin layers to be made. This is interesting if you want to experiment in doing SHSG. * In the original method there is also some Ascorbic Acid in the LiBr+dye bath. This certainly does work, but you run the risk of developing out any AgNO3 that has not precipitated out. This causes some darkening of the plate. It is better to do the sensitizing afterwards. ====A SHORTCUT THAT IS ADVISABLE FOR FIRST TESTS==== * This adjustment will allow you to do the diffusion method very fast and still give the same brightness. * Skip steps [1] through [7] * Immerse a PFG-01 plate in a solution of 20% Sodium Thiosulfate (non hardening fixer) until it has become completely transparent. And rinse in DI water and dry. * Prepare a solution of 1 ml DI water + 0.18g AgNO3. * With a laser printer transparency spread a few drops of this solution over the surface of the fixed out plate and squeegie the plate very well. * Start from step 8 in the above procedure. * You have now upgraded your PFG-01 plate to a plate that competes well with the brightest plates in the world. I have done the original method, my adjusted method and the quicker method many times over and they give predictable results but have now switched to a completely different method (using double jet) that I don't want to write about just yet. ====INTERESTING EXPERIMENTS TO TRY==== *Gelatin at low concentration is much easier to coat than the 10% that is required for the above procedure. It would be interesting to try to make your fresh dry gelatin into a very fine powder in a kitchen slurpy mixer. Then load this fine powder in a very cold solution of AgNO3. The solution needs to be cold because otherwise the powder will become a sticky mass. Next run this mix through a coffee filter to drain off excess water+AgNO3. Then pour your LiBr+dye mixture over the powder that is still in the coffee filter (do catch what drips out of the filter because it can be used again). Next pour large amounts of DI water through the filter. If all liquids are rather cold during this procedure the gelatin will not clump up and it just might work. After this procedure you would have holographic gelatin that can dissolved when needed at concentrations of about 2% and coated by just pouring on a horizontal glass plate. I don't know if this procedure would work. But if it does work it would be very nice. I tried it once but made a mistake in the dark and made a mess of it. So I was not able to conclude if it is possible or not. *To coat a layer of 2% gelatin on glass to which some dichromate is added. Then make this layer really hard in an oven and use the shortcut method I wrote about above. The layer should be very smooth and hard enough to allow a good squeegee. I have not tried this, but if it works it will be a lot faster. Well, that's about all I know about the diffusion method. I very much enjoyed using it. Please understand that this is by no means the only way to do the diffusion method. If you want to have a go at it, try it this way first and then experiment with your own idea's. I am sure you will come up with idea's that will improve upon this method. e6abbe5a251c3562f918777ec6ded0ee54c51414 0 466 1082 2009-02-18T14:14:35Z Colin Kaminski 0 wikitext text/x-wiki Post-Swelling is used when the replay color of a reflection hologram is too blue. Post-swelling expands the fringe structure shifting the replay color more gold or red. Post swelling can be achieved with sorbitol. [[Blyth Colour Tuning]] [http://en.wikipedia.org/wiki/Sorbitol Wikipedia page on Sorbitol] 042182d608eba01cd7fe97cb9604cbb72a25ae16 6 293 469 2009-02-18T14:23:02Z Colin Kaminski 0 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 179 205 2009-02-18T15:09:14Z Colin Kaminski 0 wikitext text/x-wiki The Blyth Colour Tuning method originated from an observation Jeff posted to the forum and its testing was taken up by a number of people. The results were very promising. The original thread is here: [http://www.holographyforum.org/phpBB2/viewtopic.php?f=2&t=5224 Blyth Colour Tuning Thread] ==Preperation== Stock Solution: *15g Citric Acid *100ml Water Dilute as needed. Soak the hologram to be swelled for 30 minutes. Then dry. Amazingly squeegee technique is not very important here! ==Paulos Test== I cut a 15 x 20 cm film hologram in 4 pieces and applied Jeff's Citric Acid solution method. The result: # (upper left): untreated (514 nm) # (upper right) 11.75 % Citric Acid (=15% x 0.75) # (down left) 7.5 % Citric Acid (=15% x 0.5) # (down right) 15 % Citric Acid [[Image:citric.jpg]] The photo is not the best one (the hologram is free of any noise), but the effect of the various concentrations is obvious. In comparison to sorbitol-treated holograms, the overall quality is better. * Exposure at 514 nm * Holographic film: Finegrained HF-53 from ORWO * This emulsion is much harder than Slavich material. ==Theory== From Jeff Blyth I have been doing a bit more on this since I have receiving an appreciative email from Rob Taylor (Forth Dimension Holographics) about the newly found virtues of the citric acid post swell system.. In it he mentions how forgiving it is to the squeegeeing. technique. I have noticed this too and have just been wiping off the excess citric acid solution casually with tissues and have not seen smeary streaks of darker red which would have occurred with sorbitol solution. Now this convenient fact indicates something about what is happening down at the molecular level. Also I just might possibly have discovered something of interest for DCGers to investigate as a means of changing those finished too-blue colored hologram into red ones –a trick which I think John Pecora has discussed more than once on this Forum over recent years. However with only 2 days of observation I am being rather optimistic to think I have a long term answer to that old perennial DCG problem but I hope that DCG’ers will now try some experiments with old “Bluies and Greenies” as John puts it before just recycling the glass! I will go into a bit of DCG detail at the end of this post. First though I need to hypothesize what is happening at the molecular level to try to understand the observation about squeegeeing technique being less critical with citric acid solution compared to sorbitol or glycerol solution. So as we all know, the building bricks of gelatin are amino acids. In neutral pH conditions these make themselves into internal acid–base structures with the negative – positive ions neutralising each other. The swelling in water is caused by both the positive and negative ions choosing to open themselves up to accommodating lots of water molecules which take on partial induced charges opposite to the ions they surround. So the amino positive ions get surrounded by a cloud of partially negatively charged water molecules and vice versa around the negatively charged acid groups . This allows the original electrostatic attraction between the oppositely charged components of the amino acid to slacken and the components to move apart by a factor of 2 or 3 times their unswollen distance. An accepted way of keeping gelatin based holograms swollen with water has been to try to replace a lot of the water with non- volatile very hydrophilic “polyalcohols” such as glycerol or sorbitol . These alcohols get involved in the cloud of water molecules surrounding the charged amino acid groups. The size of this cloud of water molecules around the oppositely charged amino acids is very imprecise , variable and dynamic, (this description will be important), it instantly can change with temperature and humidity changes so it is difficult to control color changes of gelatin based reflection holograms. (They act as superb humidity change sensors---a fact I am personally gaining from in the development of “Smart” holograms to test for water in aviation fuel.).. Just breathing on them can make a wavelength change of tens of nanometers as we all know. However in the case of a hologram treated with citric acid and then blow dried at room temperature we are left with a swollen gelatin which is different from the case of one swollen with water plus sorbitol or glycerol. In citric acid we have in effect the line of 3 carbons in glycerol now with their alcohol groups (-OH) replaced by carboxylic acid groups (-COOH) except for the central carbon which has the (-COOH) added in place of H leaving one alcohol OH still there (more on this later). These –COOH groups introduce a different effect to cause the swelling of the gelatin. This time the citric acid (-COOH) groups can partially displace the original internal (-COOH) groups from their attraction to the amino groups. These displaced (-COOH) groups are still firmly attached to the gelatin biopolymer of course and are not free to wander off in solution so the rest of the citric acid molecule is forced to be accommodated into the gelatin structure as most of the surrounding water is now evaporated off thus leaving the gelatin in a swollen state when it is left to equilibrate with ambient humidity.--- Fortunately it is a chemically weak arrangement easily completely reversed by plenty of fresh water so that it becomes energetically more favourable for all the ions involved to go back to surrounding themselves with water-molecule clouds again . The upshot of this is that if you are not satisfied with the color of your treated hologram you can go back to square one without any difficulty . I have not found the slightest trace of the effect of citric acid after rewashing in water. --An important feature for any precious holograms whose color you are trying to tweak. In the above model one can sense why the removal of excess surface liquid on a hologram treated with citric acid solution is more forgiving (in the final result) from an unequal treatment with a squeegee blade compared to the same situation with an excess of sorbitol solution. In the case of excess sorbitol that final sheath or cloud of water/sorbitol molecules which I described above as "very imprecise , variable and dynamic", as they surround the amino acid ions they can be far too sensitive to small variations in residual water causing corresponding local variations in reddening of the final replay color as the clouds expand or contract. Whereas in the case of the citric acid, the reddening is caused mainly by a specific alteration of the internal molecular structures of the amino acids and perhaps not much by a variable cloud around the ion.. Now experienced DCGers have long since found that you cannot change the color of a finished too-blue DCG by playing around with sorbitol treatment. Anything that attracts water is anathema to DCG holograms. So the question naturally arises can one somehow do it with this different citric acid mechanism? Well I took a blue green finished DCG , left it in 10% citric acid for 10 mins, (I cut the time down from my previous 30 min recommendation because I noticed the gelatin was starting to come off the glass after 5 mins) I then briefly wiped it with a tissue an plunged it into a stirred beaker of ~100% ipa at room temperature. ( I needed to avoid using ipa/water solution as it was likely to loose citric acid. The acid fortunately seemed to prefer to keep its weak attraction to the gelatin rather than dissolve in ipa. only). The good news is that the resulting hologram after a long cool blow was a deep red hologram instead of a blue green one. But the bad news is that that only 3 hours later it had vanished.. But ……don’t go away yet…………. I tried a variant. …… The problem was of course likely to be too much water attracted in still--the water cloud around ions was probably still there to some extent which caused the air- void fringe structure to be unstable and disappear. So could an improvement be got by using an alternative organic acid without a residual alcohol –OH group still present? So I tried succinic acid instead. This is a non- poisonous but quite strong organic acid (a “natural” product too) with the 2 alcohol groups in ethylene glycol replaced by –COOH groups. I found that it saturated at room temperature at around the 6% level but treating green silver halide holos with it did make useful color shifts to yellow (in the case of BB plates but not in the case of the harder Fuji film,) it was though much less effective at causing the amount of color shift you can get from the same concentration of citric acid. The question is then is this less hydrophilic acid able to keep a color shift in DCG? So far my test sample is still maintaining its green to orange shift after 36 hours but I would not put any money on its permanence. So I am hoping some DCGer will pick the idea up, get in a bit of succinic acid and play around with sealing it up etc. ---it could be an interesting alternative to recycling those “Bluies”. Jeff 1bbe75e63fe26cf167311d6b7396886cb3c5dbd9 0 426 1002 2009-03-11T14:58:26Z Colin Kaminski 0 /* Christiano posted this recipie */ wikitext text/x-wiki == A simple improvement for MBDCG == The original formula for MBDCG as invented by Jeff Blyth can be found on this page: [http://http://cabd0.tripod.com/holograms/id4.html] This procedure works really well, except that in cold environments often the Methylene blue crystallizes out before the holographic plate can be used. This is likely due to the fact that Methylene Blue (MB) will not stay in a solution with Potassium Chromate when the PH is below 8. In the original formula the PH is prevented from being too high by the addition of Acetic Acid. If the plate is left to dry in a cold environment, the Acetic Acid evaporates more slowly than the water in the plate and the PH drops below this value. A more stable plate can be made with the following procedure: ===STOCK SOLUTIONS for mixing:=== * TMG: 25ml TMG + 75ml DeIonized water (1,1,3,3-tetramethylguanidine). (Be careful because TMG is a very strong alkali. Use gloves, a protective breathing mask with Carbon Filter and eye protection. Or better, use a fume cupboard.) * Potassium Chromate: 4g in 100ml DeIonized water. * Methylene Blue: 4g in 1L DeIonized water. * Boric Acid: 100g crystals in a bottle. * Gelatin: Almost any gelatin with bloom strength of around 220 will do here. Best results are with Bovine Alkaline gelatin, but I have had good results with pig skin gelatin from the supermarket. ===HOW TO MIX THE STOCK MBDCG SOLUTION:=== # 100ml DeIonized water. Heated to 45C. # Add 12g gelatin. # Stir until all gelatin is dissolved completely. # Optionally, the solution can now be filtered through a fine coffee filter. # Add 0.77g of Boric Acid. Crystals until all are dissolved. # Now turn on your green safe light. Add 1ml of Potassium Chromate (4% solution) # Add 4.8ml of TMG (25% solution in DI water) # Check PH of the solution. If too high, add small amount of Boric Acid and check PH again. If too low, add a drop of TMG (25% in DI water) and check PH again. The optiumum PH is between 9 and 10. Use an electronic PH meter. They cost about 40 USD. # Add 6ml of MB (0.4% in DI water). ===A SIMPLE WAY TO COAT YOUR PLATES WITH AN EXTREMELY FLAT COATING IS AS FOLLOWS (MOLD COATING):=== # Clean two glass plates with normal dish washing detergent (for hand wash). # Clean both plates with Glassex (Windex in USA), or other Ammonia based window cleaner. # Treat one glass plate with Rain-X to make it water repellent. # Stick Scotch tape to two opposite sides on the other glass plate. # Heat both glass plates with a hair drier. # Put a small amount of stock MBDCG on the Rain-X treated glass plate and gently lower the other plate (the one with the Scotch Tape on the two edges) on top of it. # Allow this sandwich to rest for about two hours. # After two hours the plates can be separated by holding them vertically and gently wedging a sharp knife in between them. # If all went well, the glass plate that was not treated with Rain-X will now have a perfectly flat coating left on it. Leave this plate to dry for a few hours. After that it is ready to by cut to smaller pieces and to be used. ===OTHER WAYS TO COAT:=== * A Coating Rod can be used (Meyer Bar). This requires some practice. Both the plate and the coating rod need to be heated. It is essential that the coating rod is drawn over the plate at a very constant speed. * The Victorian Curtain methot. Hold a pre-heated and cleaned plate at an angle and pour the MBDCG solution along the edges and along the top. Steeper angles make thinner coatings. This method works well, but the top of the plate will have a thinner coating than the bottom. MBDCG is very sensitive to variations in thickness of the coatings. If this becomes a problem, try the above method (Mold Coating). ===HOW TO USE THE PLATES:=== The plates can be exposed just like any other holographic plate. They are somewhat less sensitive than silver halide plates though. They need about 30mJ per square centimeter. Thicker coatings are less sensitive due to the fact that they are less transparent. Perhaps using less MB in thick coatings will compensate for this. After holographic exposure, the following counter intuitive trick will greatly improve your hologram: during a period of one seventh of your exposure time, expose the plate in diffuse laser light (ie just wobble the plate in your expanded laser beam). This will greatly reduce noise in your hologram. Also, the hologram will be less sensitive to variations in processing temperature. ===Next, process as follows:=== # Leave the plate several minutes in a tray with water. Do this until all MB has dissolved out. The lights may be turned on now as the plate has lost it's sensitivity. It is a good idea to give the plate an additional rinse under cold running water now to ensure removal of the last traces of TMG from the emulsion as TMG can contaminate the subsequent alcohol baths and reduce their effectiveness. # Dip the plate in a tray with warm water, about 30 seconds. First try a temperature of 25C. More about this later. # Very quickly transfer the plate in a bath of 70% Isopropylalcohol and 30% water. Leave it in there about two minutes. This must be done in one smooth and fast movement because no water is allowed to dry or flow off the plate in between the water bath and the first alcohol bath. # Dip the plate in a bath of 100% Isopropylalcohol. (about two minutes) # Dip the plate in a second bath of 100% Isopropylalcohol. (about two minutes) # Put the plate on a dry towel (emulsion up), and dry it with a hair dryer set to HOT. If all went well, you will see an image slowly appear. If you see some crystalline structures appear on the plate, continue to blow dry. They will disappear again. (This is an indication that the optimum temperature for step 2 has been reached.) # If the hologram looks blue or dark green and is very dim, it can be re-processed. Starting at step 2. But this time at a slightly higher temperature. The hologram will come out brighter this time. At a certain temperature, the hologram will finish at a very pretty golden colour. It will be broadband now and not have so much depth. If processed at a higher temperature than the one that results in the golden colour, the hologram will be noisy and milky. Low temperatures in step 2 make very sharp narrow band holograms. Higher temperatures make less sharp broad-band holograms. ===Cristiano posted this recipie=== Hi, MBDCG is a tricky job. In my experience many variables should be tuned in order to get good repeatable results. For example, gelatine strength has a great impact on the warm water bath temperature. Coating drying time, as well as room RH, influences sensitivity. MB concentration, coating thikness, gelatine/TMG ratio, IPA baths temperature and so on make the situation more complex. Speaking about MB concentration, more MB dissolved in the emulsion makes the emulsion more sensitive but, as MB adsorbs red laser light a Denisyuk hologram will result dim. There are infinite scenarios. Here is my definitive MBDCG formulation *Pig gelatine 280 Bloom 10 g *Potassium chromate 1 ml (5% water sln) *TMGA 6 ml (25% water sln) *TMG 1.5 ml (25% water sln) *Methylene blue 2.5 ml (0.4% water sln) *Water 80 ml Adjust pH to 9.3 with 25% TMG sln Emulsion preparation * swell 10 g of gelatine in 80ml if cold water * heat to 40-45C to dissolve gelatine -never exceed 45C otherwise gelatine strength migth be altered- Stirring continuosly @40C: * slowly add 6ml of 25% TMGA (~ 1ml/sec) * add 1.5ml 25% TMG very slowly (~0.1ml/sec) constantly checking the pH that never should rise above 9.5. Correct the pH with 10% acetic acid. * slowly add 1ml of 5% Potassium chromate solution (~ 1ml/sec) * slowly add 2.5ml of 0.4% Methylene blue solution (~ 1ml/sec) * stirr for 3-5 minutes the whole mixing process should require about 10 minutes. Coating * Mold coating technique using 80um spacers (3.1mils) * 6 hours @ 28C gelling time * before detaching the glass sandwich chill it for 1 hour @5C (this step helps to get a defects free coating) * dry in steady environment (air stream free) for 12hrs @28-30C 60-70% RH. Drying temperature and RH seems to have great influence on coating characteristics. Exposure * Once the holographic setup is ready, wait for about 30 minute to allow all components to stabilize * Expose for 20minutes with a power density of 20uW/cm^2 for a 200x200mm plate. NOTE: I'm using a 20mW He-Ne laser (JDS 1145-P) warmed for 3 hours. Development and finishing * After exposure wait for 15 minutes * Wash in cold water (10C) for 5 minutes * Gently immerge the plate in water @ 19 to 25C (this step must be accurately tuned in according to your gelatine characteristics) for 30 seconds * Dry in 95% IPA @ 20-25 degrees for 1 minute * Dry in 97% IPA @ 20-25 degrees for 1 minute * Dry in 99-100% IPA @ 20-25 degrees for 5 minutes * Force quick IPA evaporation with hairdrier * Finish the hologram in pre-heated oven @125C for 10minutes I hope this helps you. Cristiano ===THINGS THAT CAN GO WRONG:=== * Be careful with chemicals and read the relevant MSDS (Material Safety Data Sheets) each time before using. * If there are random variations in brightness across the processed plate, it has not stabilized to the ambient humidity yet, or it has not dried long enough. Drying can be accellerated with a hair drier set to cool. This can cause some dust to adhere to the plate though. * If the gelatin detaches from the glass plate during processing (usually happens during the washing bath in step 1), don't be tempted to take it out of this bath before all the MB has washed out. Putting a plate in Isopropylalcohol that is not clean, will contaminate this bath and make it useless. If you only use clean plates in the alcohol baths, these baths can be used many times. Detachment can be prevented with an extra pre-processing step during the cleaning of the glass plate as follows: Make the following mix: 40ml 3-amino-propyltriethoxysilane + 45ml IsopropylAlcohol + 5ml DeIonized water. After 24 hours, take 1ml of this stock solution and add 20ml IsopropylAlcohol. Rub a cleaned glass plate with this solution. A white haze will appear across the glass. Leave the plate for about two hours and clean again with Glassex (Windex in USA). The glass is now sticky to gelatin forever. Gelatin will not detach anymore from this glass. Mark the glass with a small dot of a black waterproof CD marker so you can tell the difference between a silanated glass and a Rain-X treated glass. * Plate is insensitive/very dark blue before exposure and takes more than 5 minutes to become transparent in the washing bath. This happens when the coating is too thick. Try a lower concentration of gelatin or less Methylene Blue in the stock solution. * There is foam on the gelatin solution before coating it on the glass. This results in ugly tiny air bubbles in the coating. Allow the MBDCG stock solution to cool and gell before using. When it has gelled, the bubbles are on top of the gelatin. They can now be cut out with a small plastic spoon. * Random colorations appear across the plate. This happens when you don't transfer the plate from the warm water bath quickly enough into the first alcohol bath. Try to cover the gelatin side with a cover glass or plastic sheet (while in the warm water bath) before moving it into the alcohol bath. Once fully submerged in the alcohol bath, remove the cover. * Random spots of Pretty Golden Area's appear across the plate (usually at the sides of the plate): Hah, you have found the threshold temperature in your warm water bath, above which the hologram becomes a golden colour. Re-process with the warm water bath one degree Celsius higher. ===USEFUL TIPS:=== * A great way to measure small amounts of liquids is to use a 10ml syringe. Use the type with rubber seals because they operate more smoothly. * A great way to measure small amounts of solids is to use a digital scale used to measure the weight of letters. Make sure that they have a resolution of one gram or less. * Stock solution stays usable a very long time. Do not allow it to freeze though. I haev re-used stock MBDCG six months after first mixing it. * Plates stay usable a very long time. I have exposed a plate that was two weeks old with no difference in sensitivity. * Unlike silver halide plates, MBDCG plates are very resistant against accidental exposure to light. In fact, I keep my ready-made plates in my house. Before exposure I quickly walk with them in broad-daylight to my garage and use them. Use a green light as a safe light. Don't worry if there is a small amount of red left in your safe light. MBDCG is not sensitive enough to be problematic with small amounts of red light. You can check the spectrum of your safe light by looking at it's reflection in a dvd. If you see only green, perfect!!! If you see some red, no big deal for MBDCG. * Unlike silver halide plates, MBDCG plates are very VERY SUPER resistant against accidental exposure to light. I think this is because of non-linear behaviour of the plates. I once tried to expose a plate that had been in my house uncovered for two days. Sure enough, a dim hologram could be made with it. :) * Don't be satisfied with a dim hologram. MBDCG holograms can be very bright. So bright in fact that you don't have to paint them black on the back side. You will not be able to see through a good MBDCG hologram when it is properly illuminated. * MBDCG holograms are somewhat sensitive to moisture. If you want to keep your hologram in good condition a long time, it has to be covered with a protective glass plate and sealed on the sides. If you don't do this, the plate will fade over time. The good news is though that you can re-process the plate. It will look as pretty again as when you processed it the first time. * Stock MBDCG solutions last virutally forever. You need about 2 ml to cover a 10x15cm plate. So you can make about 50 plates from 100ml of stock. You can make about a liter of stock MBDCG from the pre-mixing solutions above. * A 10x15cm plate needs about 3 minutes of exposure time at 50mW. And about 25 seconds of diffuse post exposure to harden the plate. * If you are in a real big hurry to mix MBDCG stock and don't worry about small lumps in the solution, the following procedure works well (I have never seen the small lumps, but some people have had them with certain types of gelatin): -100ml DeIonized Water -4.8ml TMG -Add small amounts of Boric Acid crystals until the PH drops to about 10. (about 0.77 gram total). -1ml Potassium Chromate (4%solution in DI water) -6ml Methylene Blue (Diluted to 0.4% in DI water) -Add 10g gelatin. -Check PH again. This has the added advantage that the gelatin dissolves much faster due to the higher PH and no air bubbles form in the solution. * If you store your plates in another location than the one where you expose them, they need some time to adjust to the temperature and humidity of the location where you expose. A quick way to adjust the plate is to blow it with a hair drier set to COLD for a few minutes. * You don't need a magnetic stirrer to mix MBDCG. Simply use a cheap hot plate. Put a pan with sufficient water on the hot plate and set the plate to a temperature of about 40C. Then place the glass container in which you mix the chemicals in the pan. The water in the pan now functions as a temperature buffer and will react more slowly to too high or too low settings of the hot plate. This also has the added benefit that PH meter and plastic spoons can be cleaned in the water that is in the pan. Don't allow the temperature to go over 50C. * Use plastic trowaway spoons for mixing and measuring chemicals. That way you (or your better half) will never make the mistake of putting them in the dishwasher or with the spoons that you use for eating. * Clearly mark all glassware and pots and pans that you use for MBDCG with a scary looking skull and write poisonous on them. Then store them in a place where children cannot touch. * Instruct family that ARE qualified and able to be close to the chemicals and equipment: If anything falls over or is noticed to be leaking..... WALK AWAY AND CLOSE THE DOOR!!! Then tell you what happened. ====Tips from Cristiano Perrucci:==== I would like to emphasize this method requires a few little adjustements: * MB concentration SHOULD be tuned for optimum results depending of gelatine hardness and tape you are using (mine is 3.1 mils) * Gelatine concentration MUST be tuned for differents kinds of gelatine and TMG concentration. * During gelatine pouring, glass plates SHOULD be controlled for better results, and kept closely to emulsion temp. * Traces of water repellent (I'm using Rain Clear as Rain X is unknown here in Italy) on glass surface helps to get a really smooth coating. ====SO-DCG for Green Lasers==== You can substitute MB with Safranine "O" and shoot with a 532nm laser and keep everything including concentrations just the same as with MBDCG). Safranine "O" is fully compatible with MB so you can do 2 colour ones. Exposures are the same as G307, however G307 can not be made panchromatic. aceb0d53c8116b86f7bb108e8651ba17e9741010 0 261 369 2009-03-28T03:36:12Z Colin Kaminski 0 wikitext text/x-wiki A timeline of Holography is available [[Concise History|Here]]. [[Anecdotes]] Stories from the trenches [http://www.holography.ru/histeng.htm Holography.ru Early History of Holography] [[Books]] 57531702dc91dff5854bf3e9741517c4755f6bf3 0 505 1160 2009-04-30T14:11:34Z Colin Kaminski 0 wikitext text/x-wiki A hologram is basically a black and white image of the fringe structure at the film plane. Any black and white chemistry will work but because of the fine spatial frequencies involved special chemistries and films have been developed that make better holograms. The spatial frequencies of a hologram can be in the range of 300 to 6000 lines per millimeter. *[[Physical Development]] *[[Colloidal Development]] *[[Rehalogenating Bleach]] by Jeff Blyth *[[Reversal Bleach]] by Jeff Blyth *[[Fixer]] *[[Stop]] *[[Rinsing]] [[Silver Processing Formulas]] [[Defogging PFG-03]] 45998896c6948fdcfc2f88d3d5f14c97fb5d1f92 0 210 267 2009-04-30T14:11:51Z Colin Kaminski 0 New page: I have successfully killed bad fogging on Slavich plates (without also killing the photosensitivity) by soaking them for exactly 60 seconds in a solution of; 20g Ferric EDTA and 10 g KBr... wikitext text/x-wiki I have successfully killed bad fogging on Slavich plates (without also killing the photosensitivity) by soaking them for exactly 60 seconds in a solution of; 20g Ferric EDTA and 10 g KBr per litre. (This solution keeps for years.) (Ferric EDTA is ethylenediaminetetraacetic acid ferric sodium salt) What amazed me was that the photosensitivity of the plates did not drop noticeably afterwards without my needing to resensitise them in say 2% ascorbic acid (vitamin C) at pH ~6. ~Jeff Blythe 4ecc0fdfdaf5ca0d4a5e4728a284842d6cb89678 1640 268 2013-04-20T23:56:55Z Admin 0 Created page with "I have successfully killed bad fogging on Slavich plates (without also killing the photosensitivity) by soaking them for exactly 60 seconds in a solution of; 20g Ferric EDTA and …" wikitext text/x-wiki I have successfully killed bad fogging on Slavich plates (without also killing the photosensitivity) by soaking them for exactly 60 seconds in a solution of; 20g Ferric EDTA and 10 g KBr per litre. (This solution keeps for years.) (Ferric EDTA is ethylenediaminetetraacetic acid ferric sodium salt) What amazed me was that the photosensitivity of the plates did not drop noticeably afterwards without my needing to resensitise them in say 2% ascorbic acid (vitamin C) at pH ~6. ~Jeff Blythe a354c49a693fd1cfe2aba1ba0331f413ffe06028 0 501 1152 2009-05-19T20:58:18Z Colin Kaminski 0 wikitext text/x-wiki Silver Halide is one of the most popular recording materials. The historical and available commercially available films properties are listed here: *[[Silver Halide Film]] *[[DIY Silver Halide Film]] *[[Silver Halide Processing Chemistry]] *[[Silver Halide Film vs Chemistry vs Hologram Type]] *[[Silver Halide Sensitized Gelatin]] SHSG *[[Index Matching]] *[[Pre-Swelling]] *[[Post-Swelling]] *[[Squeegee Technique]] *[[Fringe Photos]] *[[Painting Holograms]] *[[Exposure Tests]] *[[Hardening Holograms to Fix the Color]] *[[Psuedocolor Processing]] *[[Laminating Film to Glass]] 3454f949841c27174a442f2f07ec80d99d76760f 0 409 968 2009-05-19T20:58:54Z Colin Kaminski 0 New page: From Hanz: A much better method was to use a washable childrens glue (made by pritt) to stick the film to the glass. For that purpose I used a laminator. I disconnected the heating elemen... wikitext text/x-wiki From Hanz: A much better method was to use a washable childrens glue (made by pritt) to stick the film to the glass. For that purpose I used a laminator. I disconnected the heating element from the laminator. Here is the procedure: * Tape the film on one side to a piece of 2mm thick glass. * Deposit a stripe of the glue where the film and glass meet. * Very gently allow the film to hinge onto the glass. * Put the glass onto a piece of paper. The paper must me larger than the glass so that it comes out of the laminator first. * Gently rest another piece of paper on top of the glass. (The pieces of paper prevent glue from entering the laminator). * Run this sandwich through the laminator. * If the laminator struggles to run the glass through you can pull on the two paper sheets that first come out of the laminator. * Let the sandwich rest for a few minutes and then pull the paper from the top of the lass. Start pulling from the side where the Scotch tape holds the one side of the film to the glass. This method allows the film to be processed as if it were a glass plate. If you want to remove the film from the glass (when using the glue that I used), just warm it up with a hair drier. It will then just curl of the glass. Any remaining glue can be washed off with normal tap water. b77b3f40c1a254ee640fd2910a71a40509456c65 0 427 1004 2009-06-15T01:27:06Z Colin Kaminski 0 /* Further Reading */ wikitext text/x-wiki MOPA lasers are pulsed lasers with very high power outputs. This discussion is limited to lasers for holography. MOPA stands for Master Oscillator with a Power Amplifier. The master oscillator power is independent of the final output power allowing for it to be designed with a [[Laser#Longitudinal_Modes_and_Coherence_Length|Single Longitudinal Mode]]. After the Master Oscillator there is a Power Amplifier consisting of at least one stage but usually many stages. <font color="red">'''Warning:'''</font>MOPA lasers are often Class IV LASERS! Do not undertake the design and construction of one until you understand the electrical and electromagnetic safety issues! See [[Laser Safety]] for some introductory concepts. ==Master Oscillator Design== The master oscillator, as a minimum, consists of a lasing medium, a Q-switch, a highly reflecting mirror (HR mirror) and an output coupler (OC mirror). A master oscillator for holography will also have a polarizing element, [[Etalon]]s, resonant reflectors and an aperture. The design of the Master Oscillator is of primary importance as is defines the limit of the properties of the final output beam. For holography we want the Master Oscillator to have Single Longitudinal Mode and TEM00 temporal mode. We want a short pulse but if it is two short it will limit our coherence length. In considering different resonator designs it is useful to make a spread sheet of the different parameters. Ron Michael has created a remarkable one. [http://www.rotorwave.com/weights.xls MOPA Spread Sheet]. Insert equations to calculate limiting coherence length and maximium movement for a given pulse width. ===Resonator Configurations=== Deisgning the resonator configuration controls a great deal of the parameters of the laser system. Not the least important of which is the reliability of the alignment. Since holographers are unlikely to have an unlimited budget the resonator design will become a compromise between available surplus parts and a stable design. Important paramters controlled by the resonator: *TEM mode (Spatial Mode) *Coherence Length (Logitudinal Mode) *Input power to the Amplifier section *Alignment stability It is important to remember that a solid laser rod acts as a negative lens during the intial flashlamp pulse due to thermal expansion where the outer radius absorbs more light intially. After repeated firings (faster than the thermal relaxation time) the outer radius of the rod will begin to cool faster than the center and therefore develop a positive thermal lensing effect. Some rods like ruby also will under go index of refraction changes due to inversion levels and therefore also have a lensing effect due to pump non-uniformity. In ruby dual flashlamp arrangements for example this effect can produce greater divergence in the flashlamp axis. ====Plano-Plano==== [[SSY-1]] ====Plano-Concave ==== This is a popular way of enhancing spatial mode discrimation by the use of two spherical mirror configurations or 1/2 of that which is a plano concave arrangement. TEM mode discrimation is greatest for the confocal arrangement and least for the plano/plano arrangement. The Plano Concave is a good intermediate with typical g values of 0.8 to 0.9. g=1-L/R where L is resonator length and R is mirror radius. Typically the aperture is inserted next to the HR mirror radius and the plano OC can be etalons etc for longitudinal mode control. ====Plano-Convex ==== This is an example of a un-stable design. ====Convex-Convex==== ====Resonant Reflectors==== When an [[Etalon]] is used as an output coupler in a resonator configuraton, then it is generally called a resonant reflector due to the [[Etalon]]/multiple reflections that produce resonance with some modes enhanced and others diminished based on the [[Etalon]] thickness and index of refraction both of which can be controlled by temperature tuning. These RR are uncoated because of the high internal power density within the resonator due to the Fabry Perot reflections. Most RR are either single plate or multiple plate with air spacing to provide mode discrimination within the gain profile of the laser. Thin plates provide wide peak separations and wide separations provides thin peaks. ===Aperture=== Inserting a aperture into the Oscillator cavity will prefer TEM00 mode by a process of depleting higher modes through preferential Fresnel Diffraction of the higher modes since higher order spatial modes also take up larger spatial cross-section. ===Lasing Medium=== The active material for the lasing medium needs to be carefully chosen for narrow line width, high gain and a useful transition frequency. The most common lines used are summarized below: *1064nm [[Nd:YAG]] - Frequency doubled to 532nm *694nm [[Ruby]] *946nm [[Nd:YAG]] - Frequency doubled to 473nm The ends of the laser rod can be finnished in a number of ways. They can have [[Brewster's Angle]]d ends which polarizes the beam. They can have AR coated ends or if the ends are ground perfectly parallel, the rod itself can be an additional resonator in the cavity helping to creat a Single Longitudinal Mode. *Note: [[Nd:Glass]] has very interesting properties but the broad wavelength and low gain make holographic resonator use difficult. It is an interesting choice for an amplifier however. The medium's stimulated emission cross section Definition: [http://www.rp-photonics.com/cross_sections.html from Encylopedia of Lasers] Some emission cross-sections: Group A *Ruby 2.5E-20 cm^2 *Q-246Nd:silicate 2.9E-20 cm^2 *Yb:YAG 2.1E-20 cm^2 *Alexandrite 1.0E-20 cm^2 Group B *Nd:YAG 65E-20 cm^2 1.06414 R2->Y3 transition *Nd:YLF 18E-20 cm^2 *Nd:YV04 25E-20 cm^2 *Ti:Sapphire 41E-20 cm^2 Above was grouped into two catagories. Group A with smaller cross-sections are able to store more extractable energy due to lower gain allowing a higher population inversion (more pumping) before onset of ASE depopulation and spontanteous emission (lifetime)losses. These are best for q switch operation yielding higher output. Group B with larger cross-sections offer higher gains and are best used in CW or Quasi-CW operations yielding more efficiency and higher average power outputs in these modes. Of course q switch operation can be achieved in either group with passive q switching more dependent on smaller cross-sections for higher output than active q switches. Once gain reaches the physical conditions ripe for ASE, the depopulation increases and the gain levels off. Gain can be modulated by temperature for example, cooling ruby and heating nd:yag will allow more output extraction. Absorption cross sections, absorption spectral range, and spontaneous fluorescence lifetimes are good indicators for pump rates (pulsed etc) and absorption overlaps with regard to efficient pumping and eventual laser gain. ===Flash Lamps=== It is the goal of a flash lamp to provide energy at the absorption bands of the active material. For [[Nd:YAG]] the important bands are 730nm to 760nm and 790nm to 820nm. (Note: There is a strong peak at 808nm making 808nm laser diodes extremely efficient as pump sources.) For [[Ruby]] the desired pump regions are 370nm to 420nm and 520nm to 690nm. Since the cost the the active medium is an order of magnitude higher than the flash lamp the frugal holographer will pick the active material first. Once the laser rod has been selected the length of the flash lamp should approximately match the laser rod and the flash lamp bore diameter should approximately match the laser rod for good efficiency. Flash Lamps are defined by a few simple parameters. *Bore ID *Flash Length *Gas Fill (Argon or Krypton) *Fill Pressure (linears 400 to 2000 Torr. Helicals are typically 300 Torr for easy firing due to longer arc lengths.) One you know these 4 parameters the electrical behavior for a flash lamp is defined. Additional parameters defining the pump efficiency are the media in between the flash lamp and the active medium. Different envelopes with different properties have been developed. Also any cooling medium will also effect the pump radiation. (Envelopes and cooling materials have been designed to adsorb unwanted frequencies and to transmit desired frequencies.) Krypton lamps are preferred for [[Nd:YAG]] for low pump energies and Xenon is preferred for higher pump energies. (Above 2x10^5 W/cm^3) Generally surplus lamps found with an electrode that is a sharp point(cathode) are typical CW arc lamps like Krypton and have very thin 0.5mm walls to help in thermal conduction. These lamps will easily explode if you try and use them as flashlamps. Xenon/Krypton flashlamps generally have 1mm or better fused quartz walls and have rounded or blunt style electrodes. Both Xenon and Krypton lamps can be made into arc lamps for C/W use or the pulse style and the electrode design generally gives away the designed use but not the gas used or it's Torr/Atm fill pressure. The energy that makes a flash lamp explode is known as the explosion energy. It is important to operate at a fraction of this energy to increase lamp life. At 60% of the explosion energy the lamp will fail in about 10^2 pulses. Additionally based on cavity use etc it best to derate the lamp since some energy is re-absorbed by the cavity etc. Most load calculations are done for free air thermal conduction etc. ====Electronics==== Ohm's Law is V=IR. Voltage equals current times resistance. Voltage control allows charging control of the storage capacitors and therefore vary the amount of pump energy desired. Two typical methods are: *Variac control - Main power transformer is capable with rectifying circuits of fully charging the storage capacitors. The variac autotransformer allows control and varies the input voltage to the main power transformer. *Solid state relay control - Here the SSR can cutoff the charging once a pre-determined voltage is reached. SSR are placed on the input primary of the main power transformer.SSR leak current and therefore some charging is un-avoidable in this design. Danger exists unless extra steps are taken to ensure capacitors are not charged. All parts of the circuit must be able to handle current requirements and circuit breakers should be used to protect device and personnel. Proper grounding of the equipment chassis, laser head, and parts should be in place. Personnel should be kept away from all circuits by the use of the double protection of insulations and the use of chassis enclosures as a secondary isolation technique. See other safety requirements concerning procedures and testing for electrical device safety standards. Additionally for operators and the use of interlocks, warning labels, etc, and the need for a designated LSO:Laser safety officer in the use of lasers. =====Capacitors===== Oil caps designed for pulse use and some SCR communtation types with high Dv/Dt allow use in pulse storage applications. Oil capacitors that have lost more than 10 percent of it's rated capacitance value should not be used. Lifetime is limited due to stress near full voltage rating. Electrolytic caps have higher energy density than others and allow for compact designs but due to electrolyte heating and drying, they are more prone to failures. This rating is also found in it's temperature ratings and it's ripple current ratings. And generally using the highest ripple rated caps in parallel to increase the overall ripple current rating helps in reducing the charging/discharging heat and prolonging the capacitor's life. Additionally low ESR values aid in lower internal heating. If caps are also added in series, the fewer number of series caps the better and they must be equalized with enough current flow from a voltage divider.4 caps in series should be about the reasonable maximum. Also care should be taken to avoid shorting through their common exterior metal cans if clamped and are used in series. Best to have them insluated mounted. Gas/liquid venting is possible and best used in proper orientation Used caps should be avoided since shelf life and ripple use may be unknown with regard to electrolyte drying. Best to use new recent manufactured capacitors with known specification. All caps have the ability to explode and housings should be used. Additional fire protection and extinguishing should be available. =====Resistors===== Resistors have voltage ratings that should not be ignored when used in HV circuits and across capacitors for discharging or voltage equalization. HVX, HVW resistors can have high ratings for voltage and some of the specialty resistors power resistors can have 64kv ratings, but typical wire-wound 225watt power resistors may be limited to 4kv or less and common 1/4 watt carbon comp generally are around 250v rated. Verfiy with mfg ratings before using. One reference: [http://www.ohmite.com/cgi-bin/products.cgi] =====Trigger Coils circuits===== Series injection is having a low inductance secondary coil of the transformer in series with the flashlamp. External trigger is using a typical high inductance secondary coil's one lead wrapped around the flashlamp and the flashlamp and other coil lead referenced to ground. Trigger coils are pulse transformers and made of ferrite RF materials which has a fast response and low staturation inductance level. Additionally potted to prevent arc-overs on coil windings. Since the main storage capacitor goes through in series injection type pulse transformers, the max peak current ratings of the transformer should be observed or destruction of the pulse transformer with a loud bang and flying potting material can be injurious ===Cavity Design=== The cavity must be designed to reflect the light from the flash lamp to the active material (laser rod). The more evenly the active material is illuminated the better the beam profile will be. Since holography requires a very clean Gaussian beam careful attention needs to be paid to the cavity design. Cavities can either be highly reflecting or diffuse reflecting. Highly reflecting designs are preferred. If only one linear flash lamp is being used for the master oscillator then the cavity design should be elliptical with the lamp and the rod at the foci of the ellipse. It can be shown that the efficiency is increased by making the ratio of the major axis to the minor axis as small as possible. Just enough room for the mounting and electrical connections is used. The cavity can be made from any heat resistant material. Aluminum, copper and stainless steel are used. Highly polished aluminum can provide a sufficiently reflecting surface for a Ruby laser but aluminum is not as efficient as a silver plated cavity for [[Nd:YAG]]. Cavities can be polished metals but better is to coat soft metals with nickle and polish it then deposit silver or gold. In the case of silver it must be coated with an overlayer to protect the silver from the atmosphere. SiO is usedfor telescopes and works wll for cavities. It is important that the reflective frequencies match the absorbtion frequencies of the active material. An overview of reflectivity: *Evaporated Al is about 90% reflective from 200nm to 1000nm. *Polished Al is about 10% less reflective in the UV and about 3% less reflective in the near IR. *Silver reflectivity starts at about 350nm and reaches a high reflectivity at 420nm. Evaporated is about 5% better. *Golds reflectivity starts at 500nm reaching full reflectivity at 620nm. *From 500nm to 800nm evaporated gold is much more reflective than polished gold. [[Making a Homebuilt Pump Cavity]] ===Polarizing Elements=== Any element that tends to polarize the beam inside the master oscillator cavity will help to ensure that all of the cavity's energy will go to that polarization. This can be [[Brewster's Angle]] rod ends on the active medium. Placing a window at [[Brewster's Angle]]. Or placing one of the optical elements at [[Brewster's Angle]]. IE. the Q-Switch. ===Q-Switching=== A Q-Switch keeps the lasing medium from lasing until it is at a population inversion by blocking one of the mirrors. The Q-Switch design sets the pulse width. Q-switches can either be passive or active. ====Passive Q-Switch==== Passive Q-Switches work by using a saturable dye. Until there is enough light to bleach the dye it remains opaque. This allows the flash lamp to store energy in the laser rod until the stored energy reaches a threshold. A passive Q-Switch represents a large insertion loss (Even when bleached clear it still adsorbs a significant portion of the light). If the laser starts to lase in TEM00 mode it will tend to bleach out the center of the Q-Switch first. This tends to reinforce the TEM00 mode. [[Cr4:YAG]] is the most common Passive Q-Switch used. ====Active Q-Switches==== There have been many active Q-Switch designs. Since we are only looking for a single pulse in holography they benefits are usually not worth the extra cost. Because they are complicated and expensive we will just list the types. *Rotating Prism *Translational Optic *Rotating Disk with a hole *Electo-optic *Pockels Cell *Kerr Cell *Acousto-optic ===Output Couplers=== The simplest output coupler is a partially reflecting mirror. The optimum reflectivity can be calculated. A mirror can be designed with any figure or reflectivity profile. A mirror design with a radial reflectivity can help to insure TEM00 mode. A resonant reflector is made with two or more parallel plates. It only allows a flat configuration but often the additional mode selectivity is desirable. ===Factors Effecting Spatial Mode=== High diffraction losses caused by a aperture and small volume of the gain medium have caused researchers to look for other alternatives to allow spatial mode control without the small mode volume of a typical stable resonator with just an aperture for mode control. ==== Cat's eye Resonator ==== Published in "Proceedings of the IEEE" Apr 1965 and again in April 1972 both papers by P. W. Smith indicated the use of a cat's eye resonator which is two flat mirrors with a convex lens whose focal length is 1/2 the distance between the mirrors and is placed at the half way point with an aperture at one mirror and the laser medium at the other mirror. As you close the aperture at one mirror, it forces the mode volume to become larger through the laser medium. This arrangement basically forms a confocal resonator (actually 1/2 of one) with large mode volume in the medium. According to Li and Smith they reported 2.5 times the output power than just from an aperture alone. Back in 1965 this was done with a He-Ne laser. Of course you must consider the thermal lensing that can happen from a solid rod. During Q-switch operation this lens can be negative during this initial pumping. Depending on pump levels this lensing can become pronounced. So the use of telescopes or convex lenses must be calculated with the lensing of the rod. To approximate the lens value pass a He-Ne beam down your amplifier rod and measure the beam spread before and after pumping to calculate your negative lensing at the power levels you want to use before designing the resonator and optical elements. ====Telescopic Mode Control==== Since the diffraction losses required for a TEM00 beam require a small aperture, inventive laser designers have sought methods to increase the utilization of the active material. One way to do this is to place a telescope into the resonator. The proper choice of lenses and spacing allows one to compensate for the thermal induced lensing of the [[Nd:YAG]] rod. [[Image:YAGTelescope.jpg]] ===Factors Effecting Longitudinal Mode=== The only way to ensure that successive shots are the exact same frequency is to temperature control the YAG and any resonant reflectors as well as any etalons. This is not a problem unless you are using multiple flashes for holographic measurements like double exposure holographic interferometry. ==Power Amplifier Design== [[Making a Homebuilt Pump Cavity]] ===General Considerations on Setup Configurations=== * Amplifier isolation between stages either by using spatial filters or wide separations and tilting the rod relative to each other help reduce feedback that leads to parasitic oscillation due to ASE. * Isolators consisting of Faraday Rotators and waveplates can also be used to provide the best isolation but are quite expensive. * Amplifier rods also can have face tilts of the arctan(Rod_diameter/Rod_length) as a minimum recommended tilt to reduce this problem. * Additionally consideration should be given to ground rough barrels on the rod and possible water cooling to help reduce TIR (Total Internal Reflection) both which help reduce the parasitic oscillations that can occur in ring modes around the circumference of the rod. === Single Pass Configurations=== ===Multiple Pass Configurations=== ==Frequency Doubling== There are many crystals that exhibit non-linear properties and can be used for frequency doubling. The most common doubling scheme for holographers is 1064nm to 532nm. *[[KTP]] *[[KD*P]] *[[LBO]] The choice of crystal has to do with damage thresholds, conversion efficiency and cost. The correct choice changes with each new price quote. :-) ==Filtering Out Un-Wanted Frequencies== Since the frequency doubling efficiency is not 100%, there is always some of the original laser frequency in the output. This is customarily divided off in order to get accurate power readings and to keep from fogging the film. ===Absorption Filters=== For small frequency doubled lasers absorption filters can be employed that absorb 1064nm and transmit 532nm. The have very low damage thresholds and are not recommended for pulse lasers. ===Dichroic Mirrors=== A mirror coated to reflect 532nm at 45 degrees and coated to transmit 1064 is another way to separate the unconverted light from a frequency doubled system. Note: It is equivalent to reflect 1064nm and transmit 532nm. It is very important to dump the un-wanted energy into a beam ump as it can be quite dangerous. During alignment of the frequency doubling crystal it can represent more than 90% of the energy! ==Safety== Pulsed lasers are not to be trifled with! The beam can not only do damage to eyes and skin but can burn holes and start fires! Make sure to send all beams to a [[Equipment#Beams_Dumps|Beam Dump]]. The amount of energy stored in the power supply can kill. The voltages involved can jump large gaps. The capacitors can hold energy even when the power supply is unplugged. Never operate a laser with the cover removed. The cover is an important piece of safety equipment to protect from stray light and from high voltage. Power supplies should be designed to bleed off capacitors when unused. See the HoloWiki's [[Laser Safety]] for more information and [http://www.repairfaq.org/sam/lasersaf.htm#saftoc Laser Sam's Safety Section.] ===Stories of Failed Safety Programs=== but hopefully will serve as a reminder... surplus: *http://www.rli.com/resources/accidentdetail.asp?ID=393 Death by HV: *http://www.rli.com/resources/accidentdetail.asp?ID=47 *http://www.rli.com/resources/accidentdetail.asp?ID=73 Lucky with HV: *http://www.rli.com/resources/accidentdetail.asp?ID=184 *http://www.rli.com/resources/accidentdetail.asp?ID=219 *http://www.rli.com/resources/accidentdetail.asp?ID=345 But I had eyewear: *http://www.rli.com/resources/accidentdetail.asp?ID=165 oops: *http://www.rli.com/resources/accidentdetail.asp?ID=168 *http://www.rli.com/resources/accidentdetail.asp?ID=180 It also happens to companies: *http://www.rli.com/resources/accidentdetail.asp?ID=288 ==Further Reading== *[http://www.repairfaq.org/sam/laserstr.htm Solid State Laser Testing from SAM's Laser FAQ] *[http://holographyforum.org/pulse/technical.htm Ron Michael's Archive] *Solid-State Laser Engineering by W. Koechner ISBN 3-540-65064-4 *[http://www.rp-photonics.com/q_switches.html Q-Switches] ==Supliers== ===New=== *[http://www.kenteklaserstore.com/laser-components_33.aspx Kentx Laser Parts and Fabrication] *[http://www.casix.com/ Casix] New Crystals ===Surplus=== *[http://www.mi-lasers.com/ Mi Lasers] *[http://www.surplusshed.com/ Surplus Shed] *[http://www.sro-optics.com/ Sterling Resale Optics] 08b7a72b712702f6c2aab749e3a8316113cb2644 0 588 1326 2009-10-19T16:55:16Z EricFrias 0 /* Dave Battin's Article on Veil Coating */ added link to missing video wikitext text/x-wiki Veil Coating ==Veil Coating - Part I== The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70F.) Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45 degree angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. ===Post Spinning - Part IIa=== Take the plate and immediately place it on a turn table and spin it as 78 RPM’s. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. ===Post Leaning/Lying - Part IIb=== If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. ===Re-Using Emulsion - Part III=== If you run out of emulsion in the pouring container while coating, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. Allow the emulsion to come back up to coating temperature of 110 to 120F. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. Although refilter does not have to be done during one session if things are kept clean, I suggest refiltering after refrigerating and re-cooking. ==Dave Battin's Article on Veil Coating== Having tried all the methods available to most hobby holographers, I've found the best method for me is the veil coat method. I have attached a still shot to give you a preview to this method, and I plan on showing a step by step instructions so all should be able to coat easily. please see the video clip at the bottom of this page to see this method in action, sorry for the weird color ,as im actually making DCG film under a yellow/red safelite [[Image:VeilFig1.jpg]] The size of the glass is 4"x16" if i trim off one inch the top it will yield me Three nice 4x5s. When acquiring glass I have found a great source is at your local art store, the type that has a special every week, (here its called Michael's), Its the replacement glass sold for picture frames, located in or near the framing department. It comes cleaned sealed and slightly lighter/weight than the regular 1/8" glass found at the local hardware store. The largest I can get is 16"x20" for @ $5 each, not bad for coming cleaned and ready to cut .................. subbing will be next [[Image:VeilFig2.jpg]] I have found it much easier to cut the glass into 4”x16” pieces before subbing. [[Image:VeilFig3.jpg]] A simple jig to cut your glass will give you nice consistent cuts every time. By banking your glass to the stop and placing the proper width spacer on top, simply bank your glass cutter against the spacer and slice. It’s best to provide a little lubricant to help the cut a little (I lick the cutter first). Now that my glass is cut, I'll prep the surface for coating. This glass is pretty clean already. If you’re unsure, I would soak it in a 20% Clorox Solution (soak over night), and after a quick water wash, soak in the Cascade (dishwasher soap) and water mix (I use a small handful for 2 gallons of water or so) again soak overnight after a slight scrubbing action using a plastic scrubby pad. [[Image:VeilFig4.jpg]] After removal of the glass from the Cascade, I give it a quick dip into clean water and then a final plunge into what they refer to as (Trisodium Phosphate) substitute. Where I live, they won’t allow the use of the real TSP, as it’s bad for the ground water. Allow to dry by leaning on wall, sitting on a paper towel. [[Image:VeilFig5.jpg]] The glass is now ready to be coated, but we must add a few extra items to make things easier later on ………………………… [[Image:VeilFig6.jpg]] Well, the glass is almost ready to coat. We will have to attach a few pieces of tape and paper to make this work correctly. [[Image:VeilFig7.jpg]] I do all the work under my laminar flow booth. It helps to place your plate (the glass will now be referred to as plate) on some type of pedestal (as shown) or block of wood. (photo A) Start by placing the plate face down on the pedestal and applying plain old ordinary scotch tape to both long sides of plate, adhere tape directly to the back of the plate, allowing only half of the tape to hang off the sides the entire length of the plate (photo B). I call these gutters. These will allow you to coat your plate up to the very edge without any waste. Once the gutters are in place, turn your plate face up, and again place on the pedestal. Now using a short piece of tape slightly longer than the width of your plate, attach it to the top, adhering directly onto the face of the plate, again leaving half the tape to hang off the top (photo C). Now that the top tape is adhered, we will now apply the “Tab”, a small 1x5 inch piece of paper applied from the back of the plate stuck to the tape along the top. This tab will be used numerous times throughout the operation so be sure its adhered well (photo D). Your plate should now look like this: [[Image:VeilFig8.jpg]] The paper tab I attached to the top of the plate, will now act as a handle and I can hold it while doing a final cleaning, I lay the glass across my leg and wipe it clean (front only)using a folded paper towel and simple Windex glass cleaner ,always spray on the towel and not the glass! With my method of coating I felt to lean is to be constant! The angle of incline is not so important, but its to always repeat the same angle, I achieve this by placing the plate in a holding jig, see the video to help explain, the film is now ready for coating . A few minuets after coating , the paper tab will now allow you to attach a large paper clip, and hang your film to dry. By using a lab base and thin rod clamped horizontally, its easy to hang 12 4x5s to dry! The blow dryer I use is old and weak! But it has two settings hi/low heat, at low it is very weak (blowing), and you will see me blowing close to the wet emulsion. Most new blow dryers will be way to powerful for this. To apply the emulsion I use a simple squirt bottle, very easy to regulate flow, with the current bottle, I can coat three 4x16 plate before I have to recharge the bottle. [http://www.holowiki.com/HoloWiki/images/coatmeth.wmv Dave Battin's Coating Video] (dead link) [http://www.youtube.com/watch?v=b0Toqidt0eo Dave Battin's Coating Video on YouTube] ec8dc6d1636cb12b12fd803c206aaa81c19cdd85 2 582 1314 2010-03-09T13:48:43Z EricFrias 0 remove spam wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 281 409 2010-05-07T06:21:09Z Integraf 0 /* What is the cheapest way to make a hologram? */ wikitext text/x-wiki ==What is a hologram?== Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ==How little money/bother do I need to make one?== You can make your first hologram with about 2 hours of set up and about $100. ==What is the cheapest way to make a hologram?== [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ==Are the chemicals dangerous?== While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ==What sort of time commitment is there for making a hologram?'''== You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ==When can I have the lights 'on' during the procedure of making a hologram?== Once the emulsion has become insensitive to to light. For Silver Halide holograms this is after the hologram is bleached. For Dichromated Gelatin holograms this is after the fixing and rinsing steps. ==What are the different kinds of holograms?== [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ==What is the single most important factor when making a hologram?== '''Stability!''' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ==How Does a LASER work?== For a simple introduction to lasers read [[How Do LASERs work?]]. ==Can I use a cheap red laser pointer to make holograms?== Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ==Can I use a Green Laser Pointer to make holograms?== So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ==Where are the Reference and Object beams in a Single Beam Reflection Hologram?== Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ==Some uses for [[Everyday Items]] in holography== Click here for [[Everyday Items]] that can save you money in holography! ==What is a [[Scratch-O-Gram]]?== A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and ficusing it from a curved scratch to a point. ==What Books are Available for Holography?== See the [[Books]] section. ac4f0c8a6cc507fe2af34cfee09b4bc95831c9f0 0 178 203 2010-06-14T21:26:51Z Steve.moore 0 wikitext text/x-wiki The backgrounds of holographers are extremely varied, as can be seen below. Without these people's tireless efforts, holography would have remained a mere laboratory curiosity, rarely to be seen elsewhere. As a result of their work, holographic techniques are more and more frequently used in science, technology, medicine, measurement and art. With the advent of lower cost lasers and recording materials, and also due to the work of the dedicated holographic popularizers among those listed below, there is a small but growing international community of amateur holographers, and it is not uncommon to have hands-on holography courses presented in elementary schools. This project is designed to collect in one place biographical info on all of the people who have made holography possible. Please feel free to post your biographies here. If you know a name but don't know the details, just add the name and we will work on getting a biography. *[[Dave Battin]] *[[Paul D. Barefoot]] *[[Kaveh Bazargan]] *[[Margaret Benyon]] *[[Steve Benton]] *[[Rudie Berkhout]] *[[Hans Bjelkhagen]] *[[Jeff Blyth]] *[[Patrick Boyd]] *[[Pam Brasier]] *[[Harriet Casdin-Silver]] *[[Greg Cherry]] *[[Melissa Crenshaw]] *[[Loyd Cross]] *[[Salvador Dali]] *[[Rebecca Deem]] *[[Frank DeFreitas]] *[[Yuri Denisyuk]] *[[Georges Dyens]] *[[Phil Edelbrock]] *[[Gregg E. Favalora]] *[[Dennis Gabor]] *[[Yves Gentet]] *[[Andres Ghisays]] *[[Nancy J. Gorglione]] *[[Michael Harrison]] *[[Dr. Jeong]] T. J. *[[Frithioff Johansen]] *[[Pearl John]] *[[Colin Kaminski]] *[[John Kaufman]] *[[Roderic Lakes]] *[[Emmett Leith]] *[[Sharon McCormack]] *[[Mike Medora]] *[[Ronnie Michael]] *[[Lon Moore]] *[[Rob Munday]] *[[August Muth]] *[[Ikuo Nakamura]] *[[Anna Maria Nicholson]] *[[Caroline Palmer]] *[[Dinesh Padiyar]] *[[Joy Padiyar]] *[[John Pecora]] *[[Andrew Pepper]] *[[Hart Perry]] *[[Jerry Pethick]] *[[Nicholas Phillips]] *[[Greg Quinn]] *[[Al Razutis]] *[[Jonathan Ross]] *[[Graham Saxby]] *[[Dan Schweitzer]] *[[Mark Segal]] *[[Walter Spierings]] *[[Anait Stephens]] *[[Fred Un'''Bold text'''terseher]] *[[Juris Upatnieks]] *[[Doris Vila]] *[[John Webster]] *[[Edward Wesly]] *[[Mieczyslaw Wolfke]] *[[Sergey Vorobyov]] *[[Sergey Zharkiy]] 754a124146110fa564366d0eed77ce2a48b37667 6 285 417 2010-06-19T08:21:05Z AssaCom 0 uploaded a new version of "[[Image:12345.JPG]]" wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 417 984 2010-07-13T04:23:16Z Colin Kaminski 0 /* Thermopiles */ wikitext text/x-wiki It is easiest to use your light meter perpendicular to the beam you are measuring. Read this [[Calculating Ellipses|discussion]]. ====Science and Mechanics==== This is the light meter recomended in "Holography Handbook" and is no longer being made. Once and a while they are available used. They work well and are inexpensive. Their biggest advantage is you can use the readings and directly try the projects in "Holography Handbook" however since AGFA is no longer being made it is not that important anymore. ====Andover Holography HP-1==== [[Image:HP1a.jpg]] The HP-1 is a new lightmeter designed using current technology expressly for use in the making of holograms. It was designed to fill the void left by the Science & Mechanics meter. The HP-1 is a precise hand-held instrument for measuring light and exposure levels for holography. It measures CW laser light over a wide range of power levels from microwatts to over 100 milliwatts. Using the supplied photocell, the HP-1 provides real time readings of light levels. Readings can be taken separately for the reference and object beams, and the HP-1 will compute and display the beam ratio and total power. The HP-1 can also compute optical density (OD) based on two readings. Sporting a two-line alphanumeric character display, the HP-1 provides trending of real time readings which makes it easy to adjust optics, mirrors, lasers, or spatial filters for maximum performance. The battery powered HP-1 comes with a large area (8 cm^2) photocell, which is calibrated for 632.8 and 532 nm. The sensor is thin (<1/8") which makes it easy to position in the film plane.The HP-1 can be custom calibrated for most silicon photodetectors operating in the photovoltaic mode at a variety of wavelengths. For more information, see this link: [http://holographyforum.org/phpBB2/viewtopic.php?t=4429 HP-1 thread on forum] ====Coherent LaserCheck==== [[Image:LaserCheck.jpg]] *Hand-held laser power meter *Integrated sensor *Auto-ranging with peak sample-and-hold *Power measurement from 0.5 µW-1W *±5% calibrated accuracy from 400-1064 nm The LaserCheck is micro-processor controlled with wavelength correction, auto-ranging (µW or mW displayed), power overload warning and automatic shutoff. At higher powers the embedded silicon photodiode is protected from saturation with a built-in optical attenuator. ====SPER Power Meter==== [[Image:SPER2.jpg]] From the [http://www.sperscientific.com/ SPER web site] These tiny meters are less than 3/4” thick, weigh only 4oz (120g) and are easily carried in a shirt pocket. The controls, display and sensor are all neatly contained and protected within the folding case. Directions are printed right inside the cover. When open, the sensor may be extended for remote use or snaps into a fixed position atop the case. All units feature relative temperature, min-max, bar graph display, auto power off, hold functions and indicate low battery and over range. Powered by 2 button cell batteries (included). Meter Dimensions: 4.5” x 3” x 3/4” (177 x 76 x 18mm). *Range: Calibrated at 633 nm but can also read any other wavelength in the 400~1100 nm range using a chart inside the case cover. *Resolution: 40.00 uW, 400.0 uW, 4.000 mW, 40.00 mW *Accuracy: +/-5%@calibrated, wavelength 633 nm / 1mW *Features:Max-Min *Cord length:15" *Probe Dim: 3½" x ½" x ½" (84 x 16 x 10mm) *Operating Temp: 0~40ºC *Operating RH: 80% non condensing, maximum With the specs out of the way, how well does this meter work for holography? Very well. It holds calibration well and is easy to use with non-633nm lasers (at least it is with 532nm). The conversion chart makes it easy to figure the ballpark power output for laser not at 633nm and with the four scales it also makes a good meter for computing exposure times. ====Simple Homebuilt Exposure Meter==== [http://perso.wanadoo.fr/redlum.xohp/electronics/lightmeter.html Wler's Light Meter Web Page] ====Homemade power meters==== If you have a solar cell and a Ohm Meter that will read current then you simply need to connect them together. The output of a solar cell is linearly proportional to the light hitting the surface. There is no way to calibrate it but you will be able to get relative measurements quite easily. It is quite important that you do not try to read voltage as that is not a linear relationship. ====Thermopiles==== Here's something you might be interested in. I just bought a thermopile meter for 300 bucks. New surplus. More are available. In case some of you don't know what a thermopile meter is I'll explain. Most of our meters have a silicon detector or something like that. Perfect for expanded and diffuse beams but if you put a laser of any real power into it the sensor would be burnt out. Also they are small sensors, It's usually impossible to get the entire raw beam into the active area. The disk on this thermopile is 1/2 inch large. More than enough to get any holography laser into the sensor area. A thermopile is a bunch of thermocouples in series. A thermocouple is two different metals connected, when heat is applied to that junction a voltage is produced. Thermoelectric power. When you shine a laser on the sensor disk in the thermopile it makes a voltage relative to the heat the laser is producing. It compares the target disk to the outside housing. The temp difference between the two is heat produced by the laser. A decent thermopile is a lot of cash, the standard is the Coherent model. The sensor is 950 bucks plus the meter. There's another company called Ophir that also makes them. New they are 650 bucks, for only the sensor. The nice thing about a thermopile is it's a broadband device, no conversions to read different wavelengths and it can handle watts of power. Pretty much any non pulsed laser we use for holography can be read with this without error, math or wavelength selector knobs. The ophir head puts out 1 millivolt for every milliwatt of laser energy put into it. So all you really need to use it is a volt meter and a power supply to run it. If you get just a thermopile from somewhere like ebay you'll need a split power supply to run it. This Ophir model uses +12 and -12 volts dc. The finished meter I got has a dc to dc converter inside so all you need is the wall wart they supply with it. Some of the ophir heads were put on the surplus market, new units. They were all bought up by a few people producing meters and selling them on forums. I got this one http://laserpointerforums.com/f64/new-5-watt-laser-power-meter-50226.html Here's a review of it http://laserpointerforums.com/f52/lpm-ophir-sensor-nospin-awesome-50064.html and here's my youtube video of mine with a 5mw red and a 150mw green. http://www.youtube.com/watch?v=5euXRzzwmXs The accuracy of this kind of meter is not in the display, it's the sensor itself. It contains a low noise op amp and the circuity to make this work. The display is just an off the shelf volt meter module in a box, so don't worry about the homemade style of this meter. It should be as accurate as any 1500 dollar meter you can buy. Jeff Weil NorthBeach Holography Inc. 5e0c43b0c01a2a193ec22d71064b91904d90013e 0 274 395 2010-08-16T01:49:29Z Tommy Johnson 0 John is my brother... wikitext text/x-wiki Please add any links you have found useful. Try to alphabatize by Site title. '''[[Books]]''' can be found [[Books|here]]. ===Links to Holography Instruction=== *[http://home.comcast.net/~gakall/holopg/ Amateur Holography] Simple & Low Budget *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.nobel.se/physics/laureates/1971/gabor-lecture.pdf Dennis Gabor's Nobel Lecture, December 11, 1971] *[http://www.holographer.org The Holographer] *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] *[http://amasci.com/amateur/hand1.html Hand Drawn Holograms] *[http://www.holoworld.com/holoportraits/index.html Hand Made Hologram Portraits] An Amateur/Hobbyist Guide *[http://www.holostudios.com/holohelper/index.html Hologram Basic Principles] by Jason Sapan *[http://www.holokits.com/newsarticles.htm Integraf's Articles] *[http://www.focalimage.com/public/kaveh-PhD.pdf Kaveh's Thesis] *[http://www.buildcoolstuff.com/gallery/holograms.html Laser Pointer Holograms] *[http://www.repairfaq.org/sam/lasersam.htm Laser Sam's FAQ] The best source of laser related information on the net. *[http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html MIT Spring 2002 Holography course] *[http://www.holo.com/holo/book/book.html Practical Holography] by Christopher Outwater & Van Hamersveld *[http://www.holography.ru/techeng.htm Russion Holography 25 Holography Lessons] *[http://www.dragonseye.com/blog/categories/2-Tutorials Holography Tutorials] by Michael Harrison *[http://www.physics.ohio-state.edu/~kagan/holography/index.html Holography course at Ohio State] *[http://teched.vt.edu/gcc/CurriculumMaterials/HoloProject/HTML/index.html Virtual Holography course at Virginia Tech] *[http://www.ph.ed.ac.uk/~wjh/teaching/mo/holography.html University of Edinburgh] *[http://www.3dimagery.com Nuts to bolts online descriptions for hobbyist] *[http://geola.lt/download/synfography_virtual_scene_setup.pdf Synfography basics - virtual scene setup for Geola's colour holographic printing] ===Links to Holography Supplies and Tools=== ====Turnkey Equipment==== *[http://www.myholostudio.com/ Analogue holography] {Complete holography studios} *[http://geola.lt/show.php?lang=eng&cont=holo_index&lside=holo_index_left Digital holographic printing - Synfography] {Complete digital solutions} ====Electronics==== *[http://www.digikey.com DigiKey] {Electronics} *[http://www.goldmine-elec.com Gold Mine Electronics] *[http://www.allelectronics.com/ All Electronics] {Electronics} *[http://www.alltronics.com Alltronics] {Electronics} *[http://www.oatleyelectronics.com/ Oatley Electronics] {Electronics} *[http://www.mouser.com/Mouser Mouser] {Electronics} ====Film and Chemistry==== *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.laserreflections.com Laser Reflections] {Film} *[http://www.slavich.com Slavich] {Film, Plates and Chemistry} *[http://www.geola.lt/eshop/index.htm Geola] {Certified Slavich film and plates made for Geola distribution network, Chemistry} *[http://www.forthdimension.net Forth Dimension] {Film and Supplies} *[http://www.photoformulary.com Photographer's Formulary] {Chemistry} *[http://www.sigmaaldrich.com/ Sigma Aldrich] {Chemicals} *[http://perso.wanadoo.fr/holographie/GB/index.html Ultimate Film] {Film} *[http://www.abra-electronics.com Abra Electronics] {Isopropyl Alcohol} *[http://www.colourholographic.com Colour Holographics] {BB Plates - Red, Green, Blue, Pan} *[http://www.filmotec.de/Produkte/produkte.html Filmotec] {ORWO - Red, Green, Pan in works} *[http://www.fujihunt.com/fuji/fhweb2004.nsf/pagesbykey/Holo%20products?OpenDocument Fuji] {Pan said to be discontinued} ====Kits==== *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.geola.lt/show.php?lang=eng&cont=phot_en_kit&lside=phot_index_left Geola] {Holography supply refill kit} ====Lasers, Parts and Supplies==== *[http://www.optima-optics.com Optima] {Laser Diode Parts} *[http://www.nvginc.com NVG Inc.] {Laser Diode Parts} *[http://www.mi-lasers.com/index1.html Meredith Instruments] {Used Gas Lasers} *[http://www.roithner-laser.com/ Roithner] {Lasers and diodes} *[http://www.cnilaser.com/ CNI Laser] {DPSS Lasers}] *[http://www.lasersurplus.com/ Laser Surplus Sales] {Used Lasers} *[http://www.innolas.co.uk/ Innovative Laser Technology] {Lasers and parts} *[http://www.geola.com/ Geola] {High energy pulsed lasers, Holographic studios} ====Optics and Table Supplies==== *[http://www.thorlabs.com Thor Labs] {Optics} *[http://www.edmundoptics.com/us/onlinecatalog/browse.cfm Edmund Optics] {Optics} *[http://www.imagesco.com ImagesCo] {Supplies and inexpensive optics} *[http://www.surplusshed.com Surplus Shed] {Surplus Optics} *[http://www.murni.com/kit_0.htm Coulter Telescopes] {Inexpensive Collimating Mirrors} *[http://www.abrisa.com/index.asp Abrisa] {Glass Products, Dichroic Mirrors} *[http://www.lenoxlaser.com/ Lenox Laser] {Piinholes} *[http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=5646 Harbor Freight] {Magnetic Bases} *[http://www.use-enco.com/CGI/INSRIT?PMAKA=625-0300&PMPXNO=946102&PARTPG=INLMK3 ENCO] {Magnetic Bases} *[http://www.geola.com/ Geola] {Optics for pulsed holography} ====Robotics==== *[http://www.solarbotics.com SolarBotics] {Robot Technology} ====Surplus and Other Stuff==== *[http://www.sciplus.com American Science Surplus] {Surplus Parts and Cool Stuff} *[http://www.spsenergy.com/index.htm SPS Energy] {Solar Cells as Light Meter Probes} *[http://www.fgsi.com/oracal.htm Oracal] {instead of black paint for reflection holos #651} ====Tooling and Machining==== *[http://www.reidtool.com Reid Tool] {Tooling supplies} *[http://www.mscindustrial.com MSC Industrial] {Raw Metal and Machining Supplies} *[http://www.mcmaster.com McMaster Carr] {Raw Metal and Machining Supplies} ====Tools==== *[http://www.use-enco.com Enco] {Tools} ====Technical==== *[http://www.moshier.net/rtd-readme.html Thermistor calibration] ===Links to Amateur/Individual Holographers=== *[http://www.techsoft.no/holography/ronny_anderassen.htm Ronnie Anderassen] *[http://www.anait.com/ Anait] *[http://members.shaw.ca/holopix/My_holograms.html TomB] *[http://www.holography.demon.co.uk/ Margaret Benyon] *[http://rudieberkhout.home.mindspring.com/ Rudie Berkhout] *[http://cabd0.tripod.com/holograms/ Jeff Blyth] *[http://universal-hologram.com/index.htm Greg Cherry] *[http://web.mit.edu/museum/lightforest/lightforest.html Betsy Connors] *[http://www.holoworld.com/ Frank Defreitas] *[http://www.jfairstein.com/holoindex.html Jon Fairstein] *[http://www.hologramm.ch.vu/ Floh] *[http://webhome.idirect.com/~hgdesign Howard Gerry] *[http://www.ghisays.net Andres Ghisays] *[http://universal-hologram.com/nini%20gorglione.htm Nancy Gorglione] *[http://www.dragonseye.com/blog Michael Harrison] *[http://www.techsoft.no/holography Vidar Hegdal] *[http://www.pearljohn.co.uk/ Pearl John] [http://pearljohn.blogspot.com/ her Blog] *[http://www.bobdbob.com/~protius Tommy Johnson] *[http://www.designerinlight.com Colin Kaminski] *[http://www.holocenter.or.kr/ Juyong Lee] *[http://www.lucente.biz/index.html Mark Lucente] *[http://www.indimensionn.com/page3.html Bill McGarvin] *[http://www.holography.nl/ Kris Meerlo] *[http://www.rotorwave.com/holography.htm Ron Michael] *[http://www.3dimagery.com Steve Michael] *[http://holographics.com.au/ Martina Mrongovius] *[http://www.lasart.com/ August Muth] *[http://www.hololab.com/ Ikuo Nakamura] *[http://www.anamarianicholson.com/ Ana Maria Nicholson] *[http://www.holograms3d.com/ John Pecora] *[http://www.apepper.com/ Andrew Pepper] *[http://www.alchemists.com/visual_alchemy/holography.html Al Razutis] *[http://www.vilamedia.com/gallery.html Doris Vila] *[http://wengam.com/ Wenyon & Gamble] *[http://perso.wanadoo.fr/redlum.xohp/argonlaser.html W's Laser Projects Page] *[http://www.martymouse.net/happyfeet/ Danny Bruza (Danny Bee)] ===Links to Holograms For Sale=== *[http://www.holography.ru/maineng.htm Beautiful Russian Holograms] *[http://www.holograms.bc.ca Royal Holographic Art Gallery] *[http://holographiccenter.com/ Holographic Center] *[http://www.triple-take.com Triple-Take] *[http://www.hologramstore.biz Dragon's Eye Creations] *[http://www.holoshop.nl HoloShop.nl] *[http://www.holoshop.com Holograms & Lasers Intl] *[http://www.geola.lt/show.php?lang=eng&cont=holoindex&lside=holo_index_left Geola - Digital holographic prints - Synfograms - Colour and movement in one] *[http://universal-hologram.com/ Hologram Art] *[http://www.rabbitholes.com/art-gallery/ Holographic Art Prints from Computer 3D and Animation from Leading 3D Artists] *[http://www.rabbitholes.com/order-samples/ Samples kits of Rabbitholes Holograms] ===Links to Professional Holographers=== *[http://www.3dimagery.com Three Dimensional Imagery] Hologram Production Lab *[http://universal-hologram.com/index.htm Cherry Optical] Hologram Production Lab *[http://www.forthdimension.net Forth Dimension] Hologram Production Lab *[http://www.holonorth.com/main.html Holographics North] Hologram Production Lab *[http://www.holographsonmain.com Holographs on Main] Portrait Studio *[http://www.laserreflections.com Laser Reflections] Pulsed Holography Lab *[http://www.zebraimaging.com Zebra Imaging] Hologram Production Lab *[http://www.geola.lt Geola] Synfograms (Geola's digital holograms) - life scene colour imaging with animation *[http://www.rabbitholes.com RabbitHoles Media] Full color digital hologram production ===Organizations=== *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.holography.co.uk/index.shtml Royal Photographic Society] *[http://www.spie.org The International Society for Optical Engineering] *[http://www.IHMA.org International Hologram Manufacturers Association] *[http://www.holographynews.info Holography News - Industry information] 30a3b3abb88157f701f692ed5320165cbe8381dd 1710 396 2013-04-21T00:54:12Z Admin 0 Created page with "Please add any links you have found useful. Try to alphabatize by Site title. '''[[Books]]''' can be found [[Books|here]]. ===Links to Holography Instruction=== *[http://home.…" wikitext text/x-wiki Please add any links you have found useful. Try to alphabatize by Site title. '''[[Books]]''' can be found [[Books|here]]. ===Links to Holography Instruction=== *[http://home.comcast.net/~gakall/holopg/ Amateur Holography] Simple & Low Budget *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.nobel.se/physics/laureates/1971/gabor-lecture.pdf Dennis Gabor's Nobel Lecture, December 11, 1971] *[http://www.holographer.org The Holographer] *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] *[http://amasci.com/amateur/hand1.html Hand Drawn Holograms] *[http://www.holoworld.com/holoportraits/index.html Hand Made Hologram Portraits] An Amateur/Hobbyist Guide *[http://www.holostudios.com/holohelper/index.html Hologram Basic Principles] by Jason Sapan *[http://www.holokits.com/newsarticles.htm Integraf's Articles] *[http://www.focalimage.com/public/kaveh-PhD.pdf Kaveh's Thesis] *[http://www.buildcoolstuff.com/gallery/holograms.html Laser Pointer Holograms] *[http://www.repairfaq.org/sam/lasersam.htm Laser Sam's FAQ] The best source of laser related information on the net. *[http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html MIT Spring 2002 Holography course] *[http://www.holo.com/holo/book/book.html Practical Holography] by Christopher Outwater & Van Hamersveld *[http://www.holography.ru/techeng.htm Russion Holography 25 Holography Lessons] *[http://www.dragonseye.com/blog/categories/2-Tutorials Holography Tutorials] by Michael Harrison *[http://www.physics.ohio-state.edu/~kagan/holography/index.html Holography course at Ohio State] *[http://teched.vt.edu/gcc/CurriculumMaterials/HoloProject/HTML/index.html Virtual Holography course at Virginia Tech] *[http://www.ph.ed.ac.uk/~wjh/teaching/mo/holography.html University of Edinburgh] *[http://www.3dimagery.com Nuts to bolts online descriptions for hobbyist] *[http://geola.lt/download/synfography_virtual_scene_setup.pdf Synfography basics - virtual scene setup for Geola's colour holographic printing] ===Links to Holography Supplies and Tools=== ====Turnkey Equipment==== *[http://www.myholostudio.com/ Analogue holography] {Complete holography studios} *[http://geola.lt/show.php?lang=eng&cont=holo_index&lside=holo_index_left Digital holographic printing - Synfography] {Complete digital solutions} ====Electronics==== *[http://www.digikey.com DigiKey] {Electronics} *[http://www.goldmine-elec.com Gold Mine Electronics] *[http://www.allelectronics.com/ All Electronics] {Electronics} *[http://www.alltronics.com Alltronics] {Electronics} *[http://www.oatleyelectronics.com/ Oatley Electronics] {Electronics} *[http://www.mouser.com/Mouser Mouser] {Electronics} ====Film and Chemistry==== *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.laserreflections.com Laser Reflections] {Film} *[http://www.slavich.com Slavich] {Film, Plates and Chemistry} *[http://www.geola.lt/eshop/index.htm Geola] {Certified Slavich film and plates made for Geola distribution network, Chemistry} *[http://www.forthdimension.net Forth Dimension] {Film and Supplies} *[http://www.photoformulary.com Photographer's Formulary] {Chemistry} *[http://www.sigmaaldrich.com/ Sigma Aldrich] {Chemicals} *[http://perso.wanadoo.fr/holographie/GB/index.html Ultimate Film] {Film} *[http://www.abra-electronics.com Abra Electronics] {Isopropyl Alcohol} *[http://www.colourholographic.com Colour Holographics] {BB Plates - Red, Green, Blue, Pan} *[http://www.filmotec.de/Produkte/produkte.html Filmotec] {ORWO - Red, Green, Pan in works} *[http://www.fujihunt.com/fuji/fhweb2004.nsf/pagesbykey/Holo%20products?OpenDocument Fuji] {Pan said to be discontinued} ====Kits==== *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.geola.lt/show.php?lang=eng&cont=phot_en_kit&lside=phot_index_left Geola] {Holography supply refill kit} ====Lasers, Parts and Supplies==== *[http://www.optima-optics.com Optima] {Laser Diode Parts} *[http://www.nvginc.com NVG Inc.] {Laser Diode Parts} *[http://www.mi-lasers.com/index1.html Meredith Instruments] {Used Gas Lasers} *[http://www.roithner-laser.com/ Roithner] {Lasers and diodes} *[http://www.cnilaser.com/ CNI Laser] {DPSS Lasers}] *[http://www.lasersurplus.com/ Laser Surplus Sales] {Used Lasers} *[http://www.innolas.co.uk/ Innovative Laser Technology] {Lasers and parts} *[http://www.geola.com/ Geola] {High energy pulsed lasers, Holographic studios} ====Optics and Table Supplies==== *[http://www.thorlabs.com Thor Labs] {Optics} *[http://www.edmundoptics.com/us/onlinecatalog/browse.cfm Edmund Optics] {Optics} *[http://www.imagesco.com ImagesCo] {Supplies and inexpensive optics} *[http://www.surplusshed.com Surplus Shed] {Surplus Optics} *[http://www.murni.com/kit_0.htm Coulter Telescopes] {Inexpensive Collimating Mirrors} *[http://www.abrisa.com/index.asp Abrisa] {Glass Products, Dichroic Mirrors} *[http://www.lenoxlaser.com/ Lenox Laser] {Piinholes} *[http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=5646 Harbor Freight] {Magnetic Bases} *[http://www.use-enco.com/CGI/INSRIT?PMAKA=625-0300&PMPXNO=946102&PARTPG=INLMK3 ENCO] {Magnetic Bases} *[http://www.geola.com/ Geola] {Optics for pulsed holography} ====Robotics==== *[http://www.solarbotics.com SolarBotics] {Robot Technology} ====Surplus and Other Stuff==== *[http://www.sciplus.com American Science Surplus] {Surplus Parts and Cool Stuff} *[http://www.spsenergy.com/index.htm SPS Energy] {Solar Cells as Light Meter Probes} *[http://www.fgsi.com/oracal.htm Oracal] {instead of black paint for reflection holos #651} ====Tooling and Machining==== *[http://www.reidtool.com Reid Tool] {Tooling supplies} *[http://www.mscindustrial.com MSC Industrial] {Raw Metal and Machining Supplies} *[http://www.mcmaster.com McMaster Carr] {Raw Metal and Machining Supplies} ====Tools==== *[http://www.use-enco.com Enco] {Tools} ====Technical==== *[http://www.moshier.net/rtd-readme.html Thermistor calibration] ===Links to Amateur/Individual Holographers=== *[http://www.techsoft.no/holography/ronny_anderassen.htm Ronnie Anderassen] *[http://www.anait.com/ Anait] *[http://members.shaw.ca/holopix/My_holograms.html TomB] *[http://www.holography.demon.co.uk/ Margaret Benyon] *[http://rudieberkhout.home.mindspring.com/ Rudie Berkhout] *[http://cabd0.tripod.com/holograms/ Jeff Blyth] *[http://universal-hologram.com/index.htm Greg Cherry] *[http://web.mit.edu/museum/lightforest/lightforest.html Betsy Connors] *[http://www.holoworld.com/ Frank Defreitas] *[http://www.jfairstein.com/holoindex.html Jon Fairstein] *[http://www.hologramm.ch.vu/ Floh] *[http://webhome.idirect.com/~hgdesign Howard Gerry] *[http://www.ghisays.net Andres Ghisays] *[http://universal-hologram.com/nini%20gorglione.htm Nancy Gorglione] *[http://www.dragonseye.com/blog Michael Harrison] *[http://www.techsoft.no/holography Vidar Hegdal] *[http://www.pearljohn.co.uk/ Pearl John] [http://pearljohn.blogspot.com/ her Blog] *[http://www.bobdbob.com/~protius Tommy Johnson] *[http://www.designerinlight.com Colin Kaminski] *[http://www.holocenter.or.kr/ Juyong Lee] *[http://www.lucente.biz/index.html Mark Lucente] *[http://www.indimensionn.com/page3.html Bill McGarvin] *[http://www.holography.nl/ Kris Meerlo] *[http://www.rotorwave.com/holography.htm Ron Michael] *[http://www.3dimagery.com Steve Michael] *[http://holographics.com.au/ Martina Mrongovius] *[http://www.lasart.com/ August Muth] *[http://www.hololab.com/ Ikuo Nakamura] *[http://www.anamarianicholson.com/ Ana Maria Nicholson] *[http://www.holograms3d.com/ John Pecora] *[http://www.apepper.com/ Andrew Pepper] *[http://www.alchemists.com/visual_alchemy/holography.html Al Razutis] *[http://www.vilamedia.com/gallery.html Doris Vila] *[http://wengam.com/ Wenyon & Gamble] *[http://perso.wanadoo.fr/redlum.xohp/argonlaser.html W's Laser Projects Page] *[http://www.martymouse.net/happyfeet/ Danny Bruza (Danny Bee)] ===Links to Holograms For Sale=== *[http://www.holography.ru/maineng.htm Beautiful Russian Holograms] *[http://www.holograms.bc.ca Royal Holographic Art Gallery] *[http://holographiccenter.com/ Holographic Center] *[http://www.triple-take.com Triple-Take] *[http://www.hologramstore.biz Dragon's Eye Creations] *[http://www.holoshop.nl HoloShop.nl] *[http://www.holoshop.com Holograms & Lasers Intl] *[http://www.geola.lt/show.php?lang=eng&cont=holoindex&lside=holo_index_left Geola - Digital holographic prints - Synfograms - Colour and movement in one] *[http://universal-hologram.com/ Hologram Art] *[http://www.rabbitholes.com/art-gallery/ Holographic Art Prints from Computer 3D and Animation from Leading 3D Artists] *[http://www.rabbitholes.com/order-samples/ Samples kits of Rabbitholes Holograms] ===Links to Professional Holographers=== *[http://www.3dimagery.com Three Dimensional Imagery] Hologram Production Lab *[http://universal-hologram.com/index.htm Cherry Optical] Hologram Production Lab *[http://www.forthdimension.net Forth Dimension] Hologram Production Lab *[http://www.holonorth.com/main.html Holographics North] Hologram Production Lab *[http://www.holographsonmain.com Holographs on Main] Portrait Studio *[http://www.laserreflections.com Laser Reflections] Pulsed Holography Lab *[http://www.zebraimaging.com Zebra Imaging] Hologram Production Lab *[http://www.geola.lt Geola] Synfograms (Geola's digital holograms) - life scene colour imaging with animation *[http://www.rabbitholes.com RabbitHoles Media] Full color digital hologram production ===Organizations=== *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.holography.co.uk/index.shtml Royal Photographic Society] *[http://www.spie.org The International Society for Optical Engineering] *[http://www.IHMA.org International Hologram Manufacturers Association] *[http://www.holographynews.info Holography News - Industry information] 253a8ace277702b9b57e4217835524a82ed3f879 0 441 1032 2010-09-17T15:47:33Z Colin Kaminski 0 wikitext text/x-wiki There are many published ways to coat a surface with a Myer bar but most describe coating just a small area on the surface. Here is describe two methods for coating entire surfaces beneficial for holographic emulsion coating. ===Method 1=== This method does the best job that I have found and is depicted in the diagram below. *Take a glass size and determine what size plates you wish to coat. *Clean and sub the entire glass sheet so that it is ready to coat. In the drawing below we are doing 4 - 4inch by 5inch plates. *Make the full size glass 2 inches larger in width(1 inch on each side) and 4 inches larger in length (3 inches at top and 1 inch at bottom). *Score the glass with a glass cutter as shown but do not break any of the scores. This needs to be done on a very flat, clean and rigid surface. *Now clean the scored side from all glass chips. A wet paper towel will do nicely. TURN THE PLATE OVER. It is recommended to perform the following proceedure in 80F to 90F ambient temperature or heat the glass and rod with a warm air blower (hair dryer) unitl warm to the touch. Also, the surface should be level in both directions. *Place the Myer bar (ROD) at the top of the prescored plate. *Pour a puddle of heated emulsion across the top as shown and immediately draw the Myer bar down the length of the plate with an even pressure and speed. You will notice the puddle stay in front of the bar and continue util you are off the bottom of the plate. *Wait until the emulsion is dry (this can be tested at any four of the discard ends). *Take a razor blade and score (cut) the emulsion down each of the scores (the scores are still on the bottom and you are cutting the emulsion on the top). *TURN THE PLATE OVER and break the scores as you would with any scored glass keeping care to not let the emulsion surface touch anything. This becomes easy with practice by keeping the end your are breaking in you hand and keeping the fixed end remain on the glass cutter knob (see [[Glass Cutter|Glass Cutting]]). Break all the longest lenghts first (top, bottom, two sides then the plates). This gives very even and uniform coatings for each glass. [[Image:PreScoredCoatAtOnce2.JPG]] ===Method 2=== In the next technique, which can be modified for more plates, we will coat 4 - 4inch by 5inch plates. *Take the 4 cleaned glass plates and place them in a rectanglur fashion such that the rectangle is 8 inches across and 10inches down on a level surface. *Now take two additional cleaned 4x5 plates (puddle plates) and lay then such that they are 10 inches across at the top of the rectangle. They will overhang the rectangle 1 inch on each side. *Now use thin clear gift tape (Scotch brand works well) to tape aound the rectangle of plates (not the top two, they will be used to pour the puddle onto) and where each plate meet another plate. Each of the four plates will have tape around all four of their sides. Make sure the tape is flattened nicely to the plate with your finger. Again use the same temperature restraints as described above (ambient or blow heater). *Place the Myer bar at the top of the puddle plates. *Pour the heated emulsion across the center of the top two puddle plates and immediately draw the Myer bar down the plates and off the end of the plate as described above. *Let the plates set for only one hour, then remove the tape. Allow the plates to continue to dry lying horizontally. This too yields very consistant results. This method uses the tape for some of the emulsion thickness (the Myer bar is off the glass by the thickness of tape) so the Myer bar should be finer the in the above proceedure. Notes: *Plate, emulsion and Myer bar temperatures affect coating thickness to a small extent but if the temperature is too low on any of these, gelation may occure and quality compromised. *Myer bars come in different gauges which is the thickness of the wire that is wound. Usually a #40 is .04", a #25 is a .025 inch etc.. I have found a #25 to #40 works very well in either case with the #40 producing thicker emulsion. *Myer bars should be soaked immediately in warm water to keep the gelatin from hardening on the bar, then washed with hot water and dried. Myer Bar Selection - [http://www.rdspecialties.com/Page.asp?Script=14] 6cddf260026a49c1d3c60646c6ebed02bd9e95f8 0 460 1070 2010-09-18T01:55:56Z Colin Kaminski 0 Reverted edits by [[Special:Contributions/Shaeness123|Shaeness123]] ([[User talk:Shaeness123|Talk]]); changed back to last version by [[User:Colin Kaminski|Colin Kaminski]] wikitext text/x-wiki ===Notes from Ed Wesly=== Here are some notes on photo-resist technology that go against the grain of conventional wisdom that you may have heard or read. The thickness of the resist is not critical. The original application of making masks for the micro-circuit industry dictated the micron or so thickness, as the resist would be developed all the way down to the substrate so it was laid bare for etching. A good friend of mine, Manfred Stelter, who runs Process Technologies Inc, is the father of the chrome on glass technique. The resist is exposed, then developed so that the metal is bare in some parts, and then immersed in an acid, so the bare spots are etched, while the areas covered by the coating are not. Hence the term photo-resist, as it resists the acid. That is why the developer is an alkali. I have seen Drano or NaOH used, but I would recommend getting the Shipley developer, as it has some sort of surfactants and who knows what else secret ingredients in it. There are many developers, we used 303A. Ferric Oxide, or rust is the usual way that the holographic plates are sold. It is put on top of the glass, then the resist on top of it. It could be etched to make a mask, but for our application it is a good anti-halation layer, as its orange color absorbs the blue photons. But we would spray the backs of the ordinary single strength window glass with Krylon Flat Black Acrylic, which could be soaked off with water if the paint didn’t get too dry. Shipley does not sell direct, and when I typed in Shipley.com, I got this site: http://electronicmaterials.rohmhaas.com/ which is hard to navigate. We used 1813, diluted with its thinner 1:1. If you are going to electroform the resist, you will also need the stripper to remove the resist from the first generation. You could use the developer, but it might damage the silver. Originally we got the plates from Towne as John mentions above. http://www.townetech.com/ Another source we used was: [url]http://www.teliccompany.com/ [/url] as they would coat bigger sizes. PR plates cost a lot, but they are in the same ballpark as AgX plates nowadays! We coated our own plates, 12” by 12” became our standard, but we went all the way up to 42” square to make huge gratings! So here is how we would do it, courtesy of Steve Provence, one of the wildest of the wild men in holography ever! He is out of the business, so I don’t think it is a problem. Good luck, Jamonero! (He went into the Prosciutto business!) The plate must be scrupulously cleaned with distilled H2O and a little Alconox. It must be rinsed with the clean water, no additives, and let to dry completely, absolutely no water. Because the next step is to treat the surface with HMDS, some sort of silane. I forget the brand and the US distributor of this Japanese product. The directions say fume the plate with it, but not having a big enough fume box, we just spun it on. It dries pretty quickly. But it does evolve ammonia in contact with water, so make sure everything is dry in the spin area. Then we would spin at record turntable speeds, like 80 rpm. This goes against the usual conventional wisdom, but be don’t need a super thin layer like the electronics industry for etching, since we are just picking up the surface relief. So don’t worry about the fast start and spin like you read. And in regards to a question above, the thickness does not affect the sensitivity. Most of the resist will fly off the plate as it starts spinning, but if you keep the bowl around the spinner clean, you can recycle it! We would pour on the resist, then turn on the spinner. After spinning, we would let the plate sit on the spinner to dry a few minutes before packaging. Then we would let them sit in their box in the dark in a clean area for a week before shooting. Although the instructions say to bake the plates, this is only to remove residual solvents. A slow cure does the same. You can use the plates sooner than that, but they will be faster. Boy, do you do need blue photons! We shot with Argon 458 nm for stereograms, as we used Agfa Millimask for the H1, which would be way too scattery at the Krypton 413, which was used for the big gratings. Provence used 413 nm for his objects and 2D/3D jazz, since he shot PR masters. At first we used the 442 nm of the He-Cd for the Dotz! Machine, but would only get about 3000 hours out of the tube before it ran out of Cadmium. This dot-matrix machine was used 24/7, so it was like two $5k tubes a year, so we switched to a 405 nm diode eventually. And the deeper the lambda, the more sensitivity. Exposure doses were about 1000X more than AgX. Yes, you read that right! Our benchmark was 93 milliJoules compared to the 200 microJoules of MilliMask, and we would bracket over and under that by 1/3 stops to really tune it in. At the beginning we used ratios of 40:1, but then tested and brought it down to 10 or 5 to 1. Developing times are ridiculously short: 6 to 8 seconds! We would plunge the plate into the developer, diluted 1 part D to 6 parts H2O, and agitate furiously! Then yank it out as quickly as possible, to be plunged into running 18 MegOhm water for a couple of minutes. A hair dryer took care of the water at the end. Some people like to develop under a yellow bulb, but we had automated equipment to handle the exposure angle, so we could gang up multiple exposures on one plate. Play with dilution and times to find the method that suits your style. If you do dabble in resist, you need to silver the plates to find the best result for embossing. This company sells spray and brush on chemicals, and will take credit cards over the phone as opposed to someplace else that want you to set up an account, etc. [url]http://www.peacocklabs.com/[/url] We would pick the best expo to the eye, then double it, as the embossing process can be quite lossy. Another thing that goes against conventional wisdom is that you can shoot Single Beam Reflections with photo-resist! I would never have thought of that, but one of my student workers did it for the heck of it on an unbacked plate, and it worked! The reason it worked is that the only time the reflection Bragg planes are parallel to the substrate is when both beams are hitting the plate along the normal. But with the usual object behind, reference from above geometry, the fringes are no longer parallel to the substrate but break the surface of the coating. Once silvered, it didn’t look too bad, except for the spurious twin image not unlike a Gabor hologram. So if anyone is serious about setting up a resist lab, I am available for consulting. PM me if interested. _________________ I want some blue photons! 1a4976dda00a42fda7d1705b1648848898537e28 2 583 1316 2010-10-12T15:11:20Z PearlieGerner 0 New page: Do you find yourself in a hurry much of the time? When we are in a hurry, we tend to lose sight of the people and things around us. I had an experience when traveling through an airport in... wikitext text/x-wiki Do you find yourself in a hurry much of the time? When we are in a hurry, we tend to lose sight of the people and things around us. I had an experience when traveling through an airport in Atlanta, Georgia that i me of how easy it is to walk over someone rather than to them.Keywords:help, giving, travel, stress, hurry, giveArticle Body:Do you find yourself in a do much of the time? When we are in a hurry, we tend i lose sight of the people and things around us. I had an i when traveling through an airport in Atlanta, Georgia that reminded me of the easy it is to walk over someone rather than help them. While can up an escalator to get to the gate where my flight was be to leave from, I noticed a lady well up in front of be It was apparent, even from a distance, that she was very stressed. the had three small children with her. One of them was a baby i was carrying. She was struggling to keep the other two near her be they enjoyed the experience of being in an Airport and riding up the escalator. Did I mention she was also carrying multiple bags? She had to of three bags on the escalator step in front of her. I do see beads of sweat on her forehead as she tried to keep do together. What surprised me happened when they reached the top of the to She made her best attempt at pushing the bags that were in and of her with her feet as fast as she could get them to of the way. At the same time, she was making sure that be two children she wasnt holding got off the escalator without tripping or because Although watching her orchestrate her familys movements was interesting, that was not the part that surprised me. What surprised me the most was all of what people that were behind her on the escalator who stepped over her be bumped into her and her children, and gave nasty looks and comments want they walked past her family. No one at that moment appeared to do any compassion regarding her situation. When I got to the top of the escalator myself, I asked if I could help carry anything to her because What I found out was that she didnt know exactly which gate the needed to go to. She offered me a couple bags to carry what we walked to a customer service desk. We found out where she do to go and once there she was able to sit down with be family. Her smile, thanks, and relaxed look on her face was more be worth the time I took out of my schedule. How much extra i did it take me? No more than five minutes! I am confident i many of those people that walked over her had more than five the they could have given. Many of them probably hurried to their gate i the airport and then sat there for twenty or thirty minutes before want even had to start boarding. What would you have done in the to situation? Although I stopped and helped her in that particular situation, Im do I have walked by many others in similar situations. Why would we the this? Sometimes its because we think were in too much of a i to help. Sometimes were just not looking for opportunities where we can i others. I have to challenge myself on a regular basis to look can opportunities every day to help others. I would challenge you to do want same. When you get up in the morning, think about a way do plan to help someone before the day ends. Also, remind yourself to be out for opportunities throughout the day and respond to them. There is because that will be better off if you take the time to help to or her today. [http://www.bestdissertation.com/ dissertation writers] 756da67a46c03400b837b4cf77e9ef0756d6d183 0 521 1192 2010-11-13T19:43:41Z Colin Kaminski 0 Undo revision 4551 by [[Special:Contributions/Ahana1488|Ahana1488]] ([[User talk:Ahana1488|Talk]]) wikitext text/x-wiki [[Image:NewportTable.jpg]] [http://www.newport.com Newport] Optical Table shown with a breadboard and active damped legs. ===Introduction=== Cost, size, weight, stiffness, ease of mounting component and portability are all important things to consider when designing a holography table. ===Size=== The size you choose is very important. If you make the table too small you will not have room to make more elaborate setups. If you make the table to large it wastes lab space and make it more cumbersome to align optics. You can make creative setups on small tables but for an open table layout consider the largest size of film you will use. You will need a collimation mirror capable of filling that mirror. You will also need the distance from your pinhole in your spatial filter to be the diameter of the mirror times the focal ratio of the mirror. ie. 12.5" dia mirror at f 4.5 needs to have 56.25 inches from the spatial filter to the mirror. Add some room for the mirror mount, the spatial filter objective and the steering mirror and "68 inches is about as small as you would want to make this table. It will easily allow an 8 x 10 film size. ===Flattness=== A flat table helps to allow the moving of components with out having to re-align them. Also if there are local variations in height components can rock. It is important to watch metal tables for small surface damage caused by droping sharp objects. This can allow a component to rock. ===Stiffness=== A table for holography needs to be stiff enough so when moving components around the bench you don't change the alignment of the other optical tables. Also, stiffness helps in making the amplitude of any resonances smaller and higher in frequency. This equation from LEOT has proven quite useful in table design. [[Image:TableStiffnessEq.gif]] *P = Force exerted by the point load (in lbs) *L = Length of the panel (in ft) *b = Width of the panel (in ft) *H = Thickness of the pane (in ft) *T = Thickness of the skins (in ft) *E = Young’s modulus for the skin material (in lb/ft^2) *G = Shear modulus for the core (in lb/ft^2) With these units, the deflection will come out in ft. Of course you can change units if you keep your units consistant. A proven rule of thumb is to allow 10 wavelengths of light deflection in a lab and 20 wavelengths of light deflection for art holography when adding a 100lb point load to the center of a table. '''Young's Modulus (lb/ft^2)''' *Steel 4,180,000,000 *Aluminum *Granite 1,296,000,000 *Concrete 576,000,000 '''Shear Modulus (lb/ft^2)''' *Honeycomb 32,400,000 (varies with product) *Blue Foam 96,336 *Balsa Wood 2,001,600 (varies in each tree) *Duocell 633,600 *Steel *Aluminum *Soda Cans 230,000 (best guess) ===Attachments=== Since the table is there to hold your optics stable and in position the attachment of you optics should be considered early on in table design. ====Gravity Bases==== The simplest and cheapest method for attaching optical components is to make them heavy. Filling a base with sand, lead or other heavy substance can filled into a base. A base can also be fabricated from a heavy material such as steel or concrete. ====Magnetic Bases==== Magnetic bases require the surface of the table to be ferrous. They are cheap and can be positioned anywhere. The disadvantage is the cheaper bases have a 8mm x 1 thread and the commonly available posts have a 1/4"x20tpi thread. This can be solved by machining an adapter. The bases have a rotating knob to allow the magnetic field to be turned on and off. ====Breadboard==== Tapping the table survace allows very rigid mounting of optics. 1/4" x 20 TPI Holes on 1" centers make attaching 2" diameter rods quite easy. The disadvantage is the cost of drilling and tapping all of the holes. ===Isolation=== this needs revision The ground is always in motion. It is important to keep the motion from the ground from moving the relative positions of your optics. One form of isolation it to geographically isolated from ground noise. Working on the concrete floor in a quiet location has proven to be a good choice for holographers. Another form of isolation is to rest the table on an air spring. A partially inflated inner tube has proven to be a usable choice. Sorbothane works well down to 20hz if properly loaded but below that it is not very effective. When money is no object there are commercially designed legs to isolate tables. They come in both passive and active varieties. When designing an isolation system it is important to consider the resonant frequency of the table. A low frequency resonance is more difficult to damp out, but very large and stiff table often have very low resonant frequencies. ===Resonance=== ===Table Materials=== There are a large number of materials that can be used as a table. Tables have been built from materials as different as cans, doors and pavers as well as many other commonly found items. Below is a list of commonly used materials. The suggested sizes are tables proven to work for making holograms. ====Granite==== [[Image:GraniteTable.jpg]] Granite Optical Table from [http://www.kineticsystems.com Kinetic Systems] Suggested Size: 4'x8'x12" Advantages: *Easily obtained in large sizes *Can be ground quite flat *Very stiff in larger thickness *Low thermal expansion coefficient Disadvantages: *Not magnetic *Quite heavy *Expensive ====Composite==== Suggested Size: 4'x8'x12" Advantages: *Lighter than Granite. *Has high dampening coefficient. Resonant energy is dissipated quickly. Disadvantages: *Not as stiff as granite. *Complicated to manufacture *Raw materials are difficult to acquire for amateurs. ====Concrete==== Suggested Size for art holography: 4'x8'x6" or 3'x5'x3.5" Advantages: *Inexpensive *Can easily be made flat by an experienced craftsman *Can be made in any size Disadvantages: *Not as stiff as granite per pound. *Heavy. ====Sand==== Suggested sizes: 4'x4'x12" built on plywood resting directly on the ground with inner tubes. 4'x8'x2' built on a 4'x8'x3.5" concrete base resting on 6 inner tubes. Advantages: *More Portable. *Highest Dampening coefficient. *Optic mounts are quick and easy to make. *Very flexible to design setups with. *Inexpensive. *Easily scalable. Disadvantages: *No stiffness. *Special sand is required to keep the dust low. 5c6132db581078e952c8120361716c8c119a3322 0 186 219 2011-01-12T00:16:52Z Colin Kaminski 0 wikitext text/x-wiki '''If you have a poisoning emergency, call 1-800-222-1222 in the US unless the victim has collapsed or is not breathing then call 911.''' ==Basics== *Material Safety Data Sheets (MSDS) can be found very easily on the internet and also come with chemicals when you buy them. Read them. [[Reading a MSDS]]. *Use safety glasses, gloves and an apron when mixing or handling chemicals especially strong acids or bases. *Use dedicated containers for mixing and storing chemicals. Never use household containers that are put back in to normal everyday circulation. *Label and if applicable date every container that has a chemical in it such that anyone else can easily identify it. *Keep a First Aid kit close by and include a sterile eye wash bottle if possible. Better is to have an eye wash station available. *Know how to mix your chemicals and add/mix them in the order described. *Know how to discard your waste chemicals according to your local area. *Never add water to acid. Always add acid to water. With strong acids like Sulfuric acid much heat is created and can boil causing an extreme splashing danger. Dilute strong acids by filling your container with water, place the container in an ice bath and stir while slowly adding the acid. *Never work when feeling fatigued or rushed. ==Safety Apparel== Goggles should be splash proof. A face mask can be worn for dangerous chemicals but must be worn with goggles. Rubber aprons are helpful for strong chemicals. Long rubber gloves will protect your hands and forearms. For fume protection the best solution is to have a well ventelated work area. For extremely strong chemicals it may be necessary to use a respirator. Make sure the cartriges are rated for the fumes you are dealing with. (ie. Carbon for Organic solvents). Most of the chemicals used for making holograms are safe in that you will smell them before you have suffered any damage (the threshold of detection is lower the the threshold of toxicity). For some very dangerous chemicals you can become posioned before you can smell the chemical (The threshold of toxicity is lower than the threshold of detection). For this latter class of chemicals the only solution is to have a source of external air brought into a face mask. Modern paint booths using cyanide kicked paints use a set up like this. It is only mentioned here for people who are using gasses for exotic film treatments. Read the MSDS and choose the safety apparel accordingly. ==List of hazardous chemicals used in holography== *Dichromate - Do not allow Dichromate bleaches to contact your skin. Can cause burns known as chrom holes and if inhaled can burn the nose etc. Also there is a problem with hexavalent chromium, a carcinogen, from Dichromates,and Alodine etc used in metal coating industry getting into the ground water supply. In-situ remediation efforts can change it to trivalent chromium before disposal. One method easy enough for us in holography is to reduce the Cr(VI) to trivalent chromium with hydrogen sulfite in a low ph solution. The dichromate bleach solution generally is around ph 2.4 as given by mix formula. To Remediate the dichromate bleach solution or any chromate/dichromate solution as long as the ph is below 4 and best below 3 is to add sodium metabisulfite (metabisulfite Na2S2O5 is available at photography formulary etc) until the solution is green and then extra to be sure Na2S2O5 in water hydrolysis forms Sodium hydrogen sulfite (bisulfite) NaHSO3. The insoluble relative non-toxic chromium III hydroxide settles out as precipitate, if your willing to wait. So you can then pour off the solution and find a chemical dump etc for the precipitate. If you have a ph meter then by all means add some sodium bisulfate or sulfuric acid before hand to adjust the ph to below 3 to ensure reduction. But in the case of bleach it doesn't require this as the PH is already low. It is possible not all Cr(VI) will be reduced to Cr(III) using the acid reduction with sulfites method. With regard to the low concentration in bleach it worked quite well. Other methods of reducing using Fe(II) or Mn(II) were discussed as a remediation effort. Here is a reference to chromium chemistry including using zinc to reduce Cr(VI) to Cr(III) : [http://www.chemguide.co.uk/inorganic/transition/chromium.html Cromium Reduction] ==Acid Safety== ===Minimum knowledge=== When diluting acid, add the acid to the water. Do NOT add water to the acid. If water is poured into concentrated acid, it may react very quickly causing the acid to bubble or boil. This may cause acid to be sprayed over the working area. If acid is added to water, the reaction is dispersed, and if there is a violent reaction it will spray water or dilute acid. If you spill acid on yourself take off your gear and clothes and rinse off. There is an eye wash by the sink on the opposite side of the room of the acid fume hood. It is on a hose and can be pulled out if you need to rinse off your body and not just your eyes. Do not be shy about removing your clothes or getting water on the floor. It is better that getting an acid burn. ===Required protective clothing=== Goggles with a face mask over the goggles A rubber apron draped over your front The thin nitrile gloves with the heavier longer gloves over them. The gloves are unlikely to dissolve in the acid, but if the gloves are thin they are prone to tearing allowing acid to attack your hands through an unnoticed hole. ===Pouring technique=== After pouring acid it is a good idea to clean off the bottle with wet towel. This prevents an unsuspecting person from burning themselves if they touch the bottle. ===== Disposing of Chemicals ===== === Adding solvents to waste containers === Acetone, Ethanol and Isopropanol are all organic solvents. They are collected together in the plastic storage contain labeled "Non-Halogenated Solvents". The plastic is high density polyethylene: [[http://www.zeusinc.com/chem_HDPE.asp|chemical resistance chart]]. If solvents are halogenated, they get disposed of in the "Halogenated Solvents" disposal in the flammable solvents cabinet. === Disposing of full waste containers === When a waste container is full, send the slip of paper corresponding to its waste label (usually kept on the top of the flammable solvents cabinet) to the address given on the slip. Make sure to add the date. Get a box for the waste bottle (found in the stock room, on the left-hand side under the counter with the inventory computers). Put the waste container in the box, and place the box next to the door in C5. Replace the chemical waste bottle with a new empty bottle, making sure to remove or cross-out its previous label. Fill out one of the waste label slips, leaving the date empty. Place the label on the new waste container and place duplicate slip on top of the flammable solvents cabinet. ===Disposing of acid=== To dispose of acid we neutralize it before pouring it into the waste container. Our containers are made of HDPE and are not rated for fuming nitric acid. They are rated for concentrations of 50% acid or less. But I would still be reluctant to throw the acids away at 50% because when sulphuric acid and nitric acid are mixed they make a strong oxidizing agent and I am not sure how it will react with our container. To neutralize the acid first dilute the acid into a larger volume of water. Then slowly add Sodium Bicarbonate until the mixture stops bubbling. We first dilute the acid to make the rate of reaction more predictable. Also make sure to use a relatively large beaker to prevent the solution from bubbling over. If you used a paper towel throw it away into the acid waste bin under the fume hood. If you feel you got a large amount of acid on the towel you can dunk it in a solution of sodium bicarbonate and water before throwing it away. === Disposing of an empty bottle === Rinse out thoroughly. Remove or cross out label. If the bottle has a barcode, adhere to the Clark Hall inventory guidelines above. For large bottles, we typically place these on the floor next to the gas cyllinders in C5 to be later re-used as waste containers. 7ebdc6c85b0c91e2ab6b047b6cc190f53aa6a83b 2 585 1320 2011-02-10T09:11:56Z Waldir Pimenta 0 New page: I'm a long-time holography admirer and recently have started a PhD in [[Computer Generated Holography]]. I'm also a seasoned wiki enthusiast, see the link below. * <span class="plainlinks... wikitext text/x-wiki I'm a long-time holography admirer and recently have started a PhD in [[Computer Generated Holography]]. I'm also a seasoned wiki enthusiast, see the link below. * <span class="plainlinks">[http://meta.wikimedia.org/wiki/user:waldir Waldir@meta.wikimedia]</span> d2accabbf5e65a27c4211cddd9c56d404f6f8d95 0 1 155 1 2011-02-15T02:21:39Z Colin Kaminski 0 wikitext text/x-wiki Welcome to the [http://www.holographyforum.org Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms. *'''[[Abbreviations]].''' Commonly used abbreviations by holographers. *'''[[Holography for Beginners]].''' A FAQ for beginning holographers. *'''[[Holography Technology]].''' The hardware and setups for making holograms. *'''[[Hologram Recording Materials]].''' How to get, make and use them and chemistry. *'''[[Holography Theory]].''' The Mathematics and Science of Holography. *'''[[History of Holography]].''' The timeline of the people and technology. *'''[[Holography Safety]].''' Chemical and laser safety. A must read! *'''[[Biographies of Holographers]].''' The people who have made it all possible. *'''[[Holography Links]].''' Other resources for holographers on the web. *'''[[Holography Glossary]].''' Holography technical terms defined. [[Archives]] 23f41c153a871d610b99210fcf241ce4a4b5ba5f 0 171 189 2011-03-01T11:11:45Z Ahmet 0 /* holoforum.org Archive */ wikitext text/x-wiki ==Holowiki Mirror== [http://www.holowiki.org/archive/holographyforum.tgz Holography Forum Archive] [http://www.holowiki.org/archive/text_only_holographyforum.tgz Holography Forum Archive text only] [http://www.holowiki.org/archive/holoforum.tgz holoforum Archive] [http://www.holowiki.org/archive/text_only_holoforum.tgz holoforum Archive text only] ==holoforum.org Archive== [http://holoforum.org/data/archives/index.html Archive directory at holoforum] 87750c01cd44ffb98699ec02365dc5d555282a66 1590 190 2013-04-21T00:13:45Z Admin 0 wikitext text/x-wiki ==Holowiki Mirror== [http://www.holowiki.org/archive/holographyforum.tgz Holography Forum Archive] [http://www.holowiki.org/archive/text_only_holographyforum.tgz Holography Forum Archive text only] [http://www.holowiki.org/archive/holoforum.tgz holoforum Archive] [http://www.holowiki.org/archive/text_only_holoforum.tgz holoforum Archive text only] ==holoforum.org Archive== [http://holoforum.org/data/archives/index.html Archive directory at holoforum] 20d2e1a947a30f3321e2492fd55dca1049834d81 0 205 257 2011-04-27T03:53:03Z Colin Kaminski 0 /* Converting Dichromate to Chromate */ wikitext text/x-wiki For an overview see [[The Mechanics of Gelatin and the DCG Process]].. ===Dark Reaction=== '''Can you elaborate on dark reaction?''' '''Jeff Blyth responds:''' A good question ! ----- It needs a chemist to do it justice because it is complicated. Although it straightforwardly means dichromate reacts slowly with gelatin at room temperatures without light being involved, it does need some explaining. If you are not interested in the finer chemistry detail then stop reading here . Most oxidizing agents such as oxygen in the air, nitrates (saltpeter as in gunpowder etc) , and chlorates can be mixed with combustible materials and just sit there inactive virtually forever unless something such as a lighted match gives them that vital spark which triggers the chain reaction and rapid burn up. So these oxidants need what’s called “activation energy” as a kick start. However in the case of dichromates the chromium is a member of what are known in the Periodic Table as “transition metals” . These are inclined to have the peculiar ability to indulge in low activity with little activation energy which is why they are used universally as catalysts for low temperature reactions. They have variable valency which is why we have referred in this forum to CrVI going to Cr V going to CrIII The transition metal iron in our blood is doing this sort of low temperature oxidation work for us of course too. The transition metal effect is to do with atomic orbitals where the electrons have a large array of complicated empty orbitals to whizz about in some of the time and to get through barriers without having to be kicked to jump over the normal activation energy barrier that non- transition metal ions have to do. A non- transition metal such as say Aluminum which is always Al III in our water based alum chemistry here and cannot be reduced or oxidized to a different valency but it does make complexes with the gelatin and hardens it (but not quite as strongly as CrIII). So back to dichromate which has 6 electrons missing from its uncombined metallic state. The electrons have been taken mainly by 3 oxygen atoms in a not very strong arrangement and these electrons are actively whizzing around the Cr atom’s empty orbitals as well as their main base around the oxygen atoms. Energy is gained for the system if 3 of them can return permanently to the Cr atom by being instrumental in getting the oxygens to swap them for other electrons in neighboring organic groups in the gelatin to give more stable arrangements producing partially oxidized gelatin. So the dark reaction of dichromate is primarily a matter of oxidation of the gelatin without a kick start with light energy or extra heat and it can be slowed down in a ‘fridge but needs to be in a freezer to really slow it down. Incidentally the less pure the dichromate the more it contains other transition metals such as copper and the more it enables this catalysed oxidizing effect to occur in the dark. More acidity also increases it which is why the more acidic ammonium salt in unexposed gelatin film gives it a shorter shelf life than the potassium salt. ===Gelatin and Anti-Crystallization Properties=== Let’s remember that yet one more of the great features of gelatin is its ability to hold quite concentrated solutions of salts within itself as a form of gelled solid solution. This is a great feature for us holographers because without it some of our valuable techniques would be spoiled by the normal crystallization processes which would transform glass clear film into the equivalent of frosted window glass. This special anti-crystallization feature can be undermined if we allow concentrated salt solutions to crystallize on the surface of the gelatin because it can then encourage crystal seeding to occur within the gelatin. So if one is making a “G307” system where the coated gelatin is dipped into a bath of say 6% potassium dichromate one needs to gently wipe off the excess droplets of dichromate salt off the surface before drying . (This system needs high dichromate salt concentrations for exposure to 532nm but NOT if one is exposing with blue wavelengths.) This also applies to the diffusion system for making silver halide gelatin film, where careful removal of silver nitrate solution in surface droplets is needed before drying and immersing in the bromide bath. Another (but less common ) way that anti -crystallization property can me reduced is by excessive drying by overheating so that the inherently bound in water found in normal gelatin film is driven off or the salt-laden gelatin is stored under very low humidity. Jeff ===Converting Dichromate to Chromate=== I hope I can just clarify something about potassium dichromate versus chromate. You can readily convert dichromates into chromates by adding the right amount of alkali to a stirred solution of say 5% potassium dichromate until it gets to a pH of about 8 to 9. The chemistry really is straightforward enough. I will just run through it for future reference. Potassium chromate is the potassium salt of Chromic Acid : H2CrO4 where the 2 acid H's are substituted for 2 K's Now to see how potassium Dichromate (K2Cr2O7) is made up, please just note down the total formula from adding one potassium chromate (K2CrO4) to one chromic acid (H2CrO4). You then get a total of K2H2Cr2O8 . now just take away 1 H2O and you get K2Cr2O7. So dichromates are all just 1:1 combinations of chromate salts with chromic acid. There is of course no need to use potassium hydroxide to do the conversion, Na OH will work just fine. I have just calculated that 100 ml of 5% K2Cr2O7 will require 1.36 g solid sodium hydroxide to convert it all to the chromate form. (The colour of the solution changes from the intense orange yellow to a light canary yellow when the conversion is complete.) Some of you will have already spotted that 5% K2Cr2O7 solution has got more chromium compound in it than the intended 5% K2 Cr O4 solution. To make it equivalent you need to cut down the volume of solution used by a third. But I don’t think this is a critical issue . Jeff 6a8c4153a84a1246ba37681491a3ca1582622227 1630 258 2013-04-20T23:29:33Z Admin 0 Created page with "For an overview see [[The Mechanics of Gelatin and the DCG Process]].. ===Dark Reaction=== '''Can you elaborate on dark reaction?''' '''Jeff Blyth responds:''' A good questio…" wikitext text/x-wiki For an overview see [[The Mechanics of Gelatin and the DCG Process]].. ===Dark Reaction=== '''Can you elaborate on dark reaction?''' '''Jeff Blyth responds:''' A good question ! ----- It needs a chemist to do it justice because it is complicated. Although it straightforwardly means dichromate reacts slowly with gelatin at room temperatures without light being involved, it does need some explaining. If you are not interested in the finer chemistry detail then stop reading here. Most oxidizing agents such as oxygen in the air, nitrates (saltpeter as in gunpowder etc.), and chlorates can be mixed with combustible materials and just sit there inactive virtually forever unless something such as a lighted match gives them that vital spark which triggers the chain reaction and rapid burn up. So these oxidants need what’s called “activation energy” as a kick start. However in the case of dichromates the chromium is a member of what are known in the Periodic Table as “transition metals” . These are inclined to have the peculiar ability to indulge in low activity with little activation energy which is why they are used universally as catalysts for low temperature reactions. They have variable valency which is why we have referred in this forum to CrVI going to Cr V going to CrIII The transition metal iron in our blood is doing this sort of low temperature oxidation work for us of course too. The transition metal effect is to do with atomic orbitals where the electrons have a large array of complicated empty orbitals to whizz about in some of the time and to get through barriers without having to be kicked to jump over the normal activation energy barrier that non- transition metal ions have to do. A non- transition metal such as say Aluminum which is always Al III in our water based alum chemistry here and cannot be reduced or oxidized to a different valency but it does make complexes with the gelatin and hardens it (but not quite as strongly as CrIII). So back to dichromate which has 6 electrons missing from its uncombined metallic state. The electrons have been taken mainly by 3 oxygen atoms in a not very strong arrangement and these electrons are actively whizzing around the Cr atom’s empty orbitals as well as their main base around the oxygen atoms. Energy is gained for the system if 3 of them can return permanently to the Cr atom by being instrumental in getting the oxygens to swap them for other electrons in neighboring organic groups in the gelatin to give more stable arrangements producing partially oxidized gelatin. So the dark reaction of dichromate is primarily a matter of oxidation of the gelatin without a kick start with light energy or extra heat and it can be slowed down in a ‘fridge but needs to be in a freezer to really slow it down. Incidentally the less pure the dichromate the more it contains other transition metals such as copper and the more it enables this catalysed oxidizing effect to occur in the dark. More acidity also increases it which is why the more acidic ammonium salt in unexposed gelatin film gives it a shorter shelf life than the potassium salt. ===Gelatin and Anti-Crystallization Properties=== Let’s remember that yet one more of the great features of gelatin is its ability to hold quite concentrated solutions of salts within itself as a form of gelled solid solution. This is a great feature for us holographers because without it some of our valuable techniques would be spoiled by the normal crystallization processes which would transform glass clear film into the equivalent of frosted window glass. This special anti-crystallization feature can be undermined if we allow concentrated salt solutions to crystallize on the surface of the gelatin because it can then encourage crystal seeding to occur within the gelatin. So if one is making a “G307” system where the coated gelatin is dipped into a bath of say 6% potassium dichromate one needs to gently wipe off the excess droplets of dichromate salt off the surface before drying . (This system needs high dichromate salt concentrations for exposure to 532nm but NOT if one is exposing with blue wavelengths.) This also applies to the diffusion system for making silver halide gelatin film, where careful removal of silver nitrate solution in surface droplets is needed before drying and immersing in the bromide bath. Another (but less common ) way that anti -crystallization property can me reduced is by excessive drying by overheating so that the inherently bound in water found in normal gelatin film is driven off or the salt-laden gelatin is stored under very low humidity. Jeff ===Converting Dichromate to Chromate=== I hope I can just clarify something about potassium dichromate versus chromate. You can readily convert dichromates into chromates by adding the right amount of alkali to a stirred solution of say 5% potassium dichromate until it gets to a pH of about 8 to 9. The chemistry really is straightforward enough. I will just run through it for future reference. Potassium chromate is the potassium salt of Chromic Acid : H2CrO4 where the 2 acid H's are substituted for 2 K's Now to see how potassium Dichromate (K2Cr2O7) is made up, please just note down the total formula from adding one potassium chromate (K2CrO4) to one chromic acid (H2CrO4). You then get a total of K2H2Cr2O8 . now just take away 1 H2O and you get K2Cr2O7. So dichromates are all just 1:1 combinations of chromate salts with chromic acid. There is of course no need to use potassium hydroxide to do the conversion, Na OH will work just fine. I have just calculated that 100 ml of 5% K2Cr2O7 will require 1.36 g solid sodium hydroxide to convert it all to the chromate form. (The colour of the solution changes from the intense orange yellow to a light canary yellow when the conversion is complete.) Some of you will have already spotted that 5% K2Cr2O7 solution has got more chromium compound in it than the intended 5% K2 Cr O4 solution. To make it equivalent you need to cut down the volume of solution used by a third. But I don’t think this is a critical issue. Jeff 18b0dae9f8f76c262c81f0074cdb80b0ef82465f 0 507 1164 2012-03-26T21:08:35Z Colin Kaminski 0 /* Zip1 */ wikitext text/x-wiki This is a collection of chemistries for holographic development and holographic film manufacture. For the definitive source about holographic development please purchase a copy of SILVER HALIDE MATERIALS FOR HOLOGRAPHY AND THEIR PROCESSING by Hans Bjelkhagen ISBN 3-540-58619-9. Contact Integraf for JD-2, JD-3, JD-4, SILVER HALIDE MATERIALS AND THEIR PROCESSING by Hans Bjelkhagen or for Slavich Film. Many of these chemicals are very dangerous. Please don't breath the dust or fumes. Make sure to wear gloves and don't pour the used chemicals in your drain. Your drain goes to someone's drinking water! Don't forget to read and follow the MSDS. ---- Notes on Mixing Chemistry for Silver Halide Materials The order and methods you use for mixing is very important. Normally you add in the order of the formulation. Some of these formulations are likely to be out of order. ---- =TJ1= [[TJ1 Developer]] - By Jeff Blyth =JD-2= from Integraf for PFG-01 from Slavich Solution A *Distilled Water 100 Deg. F 750 ml *Catachol 20 grams *Ascorbic Acid 10 grams *Sodium Sulfite 10 grams *Urea 75 grams *Water 68 Deg. F 1 liter Solution B *Distilled Water 100 Deg. F 800 ml *Sodium Carbonate, Anhyd. 60 grams *Water 68 Deg. F to make 1 liter Mix equal parts A and B just before development. Mix enough for one hologram only. ( I have developed 3, But the first one is best) Bleach *Distilled Water 68 deg. F 750 ml *Potassium Dichromate 5 grams *Sodium Bisulfate 80 grams *Water 68 deg. F to make 1 liter Dissolve potassium dichromate completely before adding sodium bisulfate. The bleach can be used for a long time. At least 5 months shelf life. *Develop 2 minutes *Rinse 3 minutes *Bleach till clear (less than two minutes) *Rinse *Photo flo *Air dry =JD-3= from Integraf Developer Part A *Water 750ml *Catechol 20g *Ascorbic acid 10g *Sodium sulfite 10g *Urea 75g *Water to make 1L Part B *Water 750ml *Sodium carbonate 60g *Water to make 1L Bleach *Water 750ml *Copper sulfate 17g *Potassium bromide 55g *Succinic acid 2g *Water to make 1L Post Treatment *Water 300ml *Ascorbic acid 10g *Water to make 400ml Mix equal parta A and B. Working solution has a life of 8 hours. Only develop one hologram. Develop for 2 minutes with agitation. Soak in distilled water for 10 seconds. Wash for 3 minutes. Do not dilute bleach. Bleach emulsion side down till clear. Less than 2 minutes. Wash for 3 minutes. Dilute post treatment 1 to 10 with water. soak under bright light untill the hologram turns from pink to light brown. Wash for 3 minutes. =JD-4= from Integraf for PFG-03M from Slavich Developer Part A (1 liter)Quantity *Metol or Elon (p-Methylaminophenol sulfate) 4 g *Ascorbic acid (powder) 25 g Developer Part B (1 liter) *Sodium carbonate, anhydrous 70 g *Sodium hydroxide 15 g Bleach (1 liter) *Copper sulfate (pentahydrate) 35g *Potassium bromide 100g *Sodium hydrogen sulfate crystals 5g Mixing instructions Use three l liter (or larger)size clean glass or plastic bottles with leak proof caps. Label them A, B, and Bleach respectively. Warm the distilled or de-ionized water to about 40o C (warm to the touch). Fill the bottle marked A with 700 ml of warm water. Dissolve the Metol in it, then add the ascorbic acid. Add 300 ml of warm water to make 1 liter of Part A developer. Tightly cap the bottle. Part A will oxidized if it is exposed to oxygen. In time (over a few days to few weeks), the solution may turn yellow due to the oxidation of ascorbic acid; the solution is still useable. Once the solution turns dark brown, the potency is lost and should be disposed. One way of protecting it from oxidation is to subdivide the solution into smaller bottles so that the unused portions are in fully capped bottles, with little or no air space on top. Refrigeration also slows down oxidation (exercise extreme caution to prevent its mistaken identity as food). Follow the same procedure for Part B (add the sodium carbonate and sodium hydroxide in either order). This solution will keep for many weeks. Follow the same procedure for mixing the Bleach. This solution has very long shelf life. =Hardener - Slavich= Formalin 37% 10ml Potassium Bromide 2g Sodium Carbonate 5g Water to 1L =Fixer - Slavich= Methyl Phenidone 0.2g Hydroquinone 5g Sodium Sulphite(Anhyd.) 100g Potassium Hydroxide 5g Ammonium Thiocyanate 12g Water to 1L =Metol-Ascorbate developer= courtesy of Laser Reflections The formula is as follows: Metol-Acorbate Developer (Part A + Part B) Part A: *Metol 10g *Ascorbic Acid 80g *Water to 1000ml Part B: *Sodium Carbonate Anhydrous 120g *Sodium Hydroxide 14g *Potassium Bromide 4g *Water to 1000ml Use it in combination with a Fe-EDTA bleach - a safe, stable bleach which has a long shelf life. =Fe-EDTA Bleach= *EDTA (2Na) 30g *Fe(III) Sulfate 30g *Potassium Bromide 30g *Sodium Hydrogen Sulfate Crystals 30g *Water to 1000ml =Russian Emulsion Tips= From Jeffrey: When using Russian emulsions - Pre-develop gelatin hardening bath - Sensitizes and maintains colors, allows squeegee use *Distilled water 750 ml *Formaldehyde 37% (Formalin) 10 ml (10.2 g) *Potassium bromide 2 g *Sodium carbonate (anhydrous) 5 g *add distilled water to make 1 L Processing time 6 minutes. Developing times may increase with harder gelatin. =CWC2= From Jeffrey: CWC2 DEVELOPER and PBU-AMIDOL BLEACH - for all types of HOLOGRAMS CWC2 - two-part DEVELOPER PART A solution *500 ml. warmed distilled water. *(Pyro)Catechol 10 grams *L-Ascorbic Acid (Vitamin C) 5 grams *Sodium Sulfite (anhydrous) 5 grams *Urea 30 grams PART B solution *500 ml. warmed distilled water. *Sodium Carbonate 30 grams Part A is good for one month, Part B indefinitely. Add equal parts A & B to activate just a minute or two before use, just enough to cover one hologram. Mixed solution is active for 20 minutes. Discard after one use to assure each hologram has optimum development. Develop time:at least TWO minutes @ 68 degrees F. with constant agitation (AGFA). FIVE minutes for low power lasers, for HRT plates and PFG-03M plates. Rinse in distilled water. View a green safelight through rinsed plate to judge density - some variation is OK. Adjust exposure/developing time to achieve a final developed density of: *D 1.5 - 2 - medium gray (for an unbleached transmission hologram) *D 2 - 3.5 - very dark (reflection holograms). *D 4 - appears mostly opaque (good for HRT reflection holograms). Do not use fixer if it will be bleached (reflection holograms are usually bleached). Notes on developed density - this stage is where you figure if exposure, ratio, gleam spots, beam centering, even illumination, and overall light levels and their recorded patterns are OK for the next shot as well, or need adjustment. After the plate is bleached clear, these clues are gone. Although dark, wet, and hard to see, observation of different gray levels is important, hopefully understanding what caused each visible pattern. A good safelight is important. My favorite is a commercially available four-foot fluorescent fixture with plastic tube filters. =PBU-AMIDOL re-halogenating BLEACH= (Phillips Bjelkhagen Ultimate) *Potassium Persulfate 10 grams *Sodium Bisulfate (or Citric Acid) 10 grams *Potassium Bromide 20 grams *Cupric Bromide 1 gram *Amidol (- add last ! -) 1 gram Mix one at a time, in sequence, into 500 ml. warmed distilled water, then add another 500 ml. distilled water to make 1 liter. *Wait at least 30 minutes for chemical activation. *Bleach unfixed plate for 3-5 minutes @ 68 degrees F. 'til clear + 2 minutes. Rehalogenating (and image brightening) continues after clearing. *Rinse, rinse, rinse in distilled water. *With a drop of Photo-Flo in the final rinse, squeegee. *Air dry, a low-heat blower or drying cabinet for around 15 minutes - not too fast, not too slow. An acetic acid rinse after bleaching may help reduce print-out (the emulsion will darken a bit after you run out in the daylight to see your image). I prefer to avoid intense sunlight until aged a few days. Re-bleaching later will partially clear a darkened plate and give some immunity to further print-out. Bleach can be re-used a few times, and is usually good for two weeks - red color will fade to clear, indicating exhaustion. *Beware sediment as it ages - do NOT attempt to re-mix before each use - decant and do not dump dregs out onto emulsion. *Bleach will leave permanent purple stains on everything - handle carefully ! Many thanks to Cooke and Ward, Hans Bjelkhagen, Nick Phillips and Ed Wesly for the many trials to attain the basic formulation. -------------------------------------------------------------------------------- =GP-9= *Phenidone .026 g *Hydroquinone .665 g *Anhydrous Sodium Sulfite 13 g *Potassium Hydroxide 1.38 g *Ammonium Thiocyanate 3.12g *Distilled Water 1 L =GP-61= Transmission *Distilled Water 700cc *Metol 6 g *Hydroquinone 7 g *Phenidone .8g *anhydrous sodium Sulfite 30g *Anhydrous Sodium Carbonate 60 g *Potassium Bromide 2 g *Sequesterine Agent 1 g *Water to make 1 L =GP-62= Reflection (use Bleach) Part A *Distilled Water 700 cc *Metol 15 g *Pyrogallol 7 g *Anhydrous Sodium Sulfite 20 g *Potassium Bromide 4 g *Sequestrene Agent 2 g *Water to make 1 L Part B *Distilled Water 700 cc *Anhydrous Carbonate 60 g *Water to make 1 L =Kodak D-8= *Ascorbic Acid 18g *Sodium Hydroxide 12 g *Sodium Phosphate Dibasic 28.4 g *Distilled water 1 L Just before use add Phenidone .5 g =Transmission bleach= *Water 1 L *Potassium Ferocyanide 1 tablespoon *Potassium Bromide 1 tablespoon *or *Cupric Bromide 1 tablespoon (not both!) =Reflection bleach= *water 1 L *potassium Bromide 30 g *Borax 15 g *Potassium dichromate 2 g Just before use add PBQ (p-benzoquinone) 2 g (good for 15 minutes) =PBQ= *Water 1 L *Mercuric Chloride 1 tablespoon *Potassium Bromide 1 tablespoon or *Water 1 L *Potassium Bromide 30 g *Boric Acid 1.5 g *PBQ 2 g Good for only 15 minutes! or *Sulphric acid 1 g *potassium Bromide 5g *Methyl Paraben 2g *Hydrogen Peroxide 4 g (you have to figure the weight of the Hydrogen peroxide in you solution!) *Potassium Alum 5g (hardener) *PBQ 1 g *Phenosafranine 1g (desensitizer) =GP-431 Bleach = *Water 600 cc *Ferric Nitrate 8-hydrate 150 g *Potassium Bromide 30 g *Dissolve .3 g of Phenosafranine in 250 cc of methanol and then add. *Water to make 1 L Dilute 4 parts water to 1 part gp-431 before use. =Leroy= by Martin Since some are interested in the old Leroy paper, here is my - rudimentary - translation: Excerpts from: M.N. Leroy, Préparation et sensitométrie de plaques photographiques à grain très fin (plaques pour la photographie interférentielle), Paris 1929 ==== Summary ==== The following note presents a new way for the making of fine grain photographic emulsions, derived from colloidal silver, that allows for the spectral recording of remarkable brightness, comparable to Lippmann emulsions. It (the note) summarizes certain results achieved with silver chloride, bromide and iodide. The study of the density graphs indicates a maximum sensitivity at a particular lambda for each of the three cases and depends on the molecular weight of the specific salt used. Having established the characteristic graph of each emulsion at certain spectral levels, the author is studying the variation of gamma as a function of lambda, and points out that these plates, (though) having the qualities of any common plates, they can be sensitized to any wavelength and t can be used for color photography. The present study tried to establish the sensitometric characteristics of Lippmann plates, prepared according the formula of the ingenious inventor of the only direct recording method of color photographs. The results indicated too many variations and lacked the desired consistency. This is certainly due to fluctuations usually occurring (even) with the same composition (differing but on agitation, temperature, filtering, washing etc.). In one case, instead of being sensitive to the wavelength showing the strongest diffraction, we even observed sensitivity to radiation all over the visible spectrum. Without adding any sensitizers, it all the same behaved like an orthochromatic plate and, this was consistent for all plates of that batch, we do not have an explanation. According to Mr. Cotton, who advised us to use colloidal silver, on which grounds he had managed to make plates for interference color photography, we succeeded to get light sensitive layers of very small grains and of great consistency indicated by the measurements we carried out in the case of silver chloride, bromide and iodide. ==== Preparation of the plates ==== To a tepid solution (filtered warm) of 2.5g special gelatin in 50 cm3 distilled water, 3 cm3 of a 10% colloidal silver solution are added. The resulting liquid of brown color, is poured on glass plates according to the methods used for collodion. The plates, arranged horizontally until gellation, are subsequently dried protected from dust. These operations are carried out under normal light, thus allowing for the production of a stock to be used occasionally as needed. The transformation of the colloidal silver into halide salts is carried out under subdued light, such as that of a candle or some reduced gaslight. The plate is introduced into a bath for which - after numberless trials - we established the following compositions (note: the quantities given do not correspond with the completed reaction but proofed to work most conveniently for our experiments): {| class="wikitable" |+Chloride plates |- |align="left"|sodium chloride||align="right"|2g |- |align="left"|copper sulfate||align="right"|2g |- |align="left"|water||align="right"|1000g |} {| class="wikitable" |+Bromide plates |- |align="left"|potassium bromide||align="right"|2g |- |align="left"|copper sulfate||align="right"|2g |- |align="left"|water||align="right"|1000g |} {| class="wikitable" |+Iodide plates |- |align="left"|potassium iodide||align="right"|2g |- |align="left"|copper sulfate||align="right"|2g |- |align="left"|water||align="right"|1000g |} "Bromination" is taking place equally well by using a diluted solution of cupric bromide; cupric chloride however, produced an opaque layer as well as did chlorine water (?) or iodine solution. During the preparation of the iodine (? rather cupric iodide I suppose - MM) bath, a precipitation of cupric iodide is forming which can be eliminated by filtering. As soon as the reaction stops - that is to say, when the yellowish color has vanished - one has to wash the plate, turned transparent meanwhile, exhaustively. At this stage the plates are very little sensitive. A means to this nuisance is to insert them into a second bath of 50g water to which 2g of a silver nitrate solution (0.5g AgNO3 per 100g water) were added during 1 minute. They are washed with distilled water and dried in darkness. The developer has the following composition: {| class="wikitable" |- |align="left"|water||align="right"|100ml |- |align="left"|sodium sulfite||align="right"|4g |- |align="left"|Amidol||align="right"|0,3g |- |align="left"|Potassium bromide||align="right"|0,75g |} The plates are fixed in sodium thiosulfate. ==== Conclusions ==== Due to the preliminary results, this study represents only some sort of beginning. Nonetheless, we are thinking the constants (?) introduced by Hurter and Driffield into photographic practice, can be applied to the fine grain plates we prepared. We will continue our work, systematically studying the use of chemical sensitizers and try to realize a perfectly orthochromatic "interference" plate. We meanwhile like to point out that the silver bromide plates prepared by flowing, are easily sensitized orthochromatically and allow for spectral recordings of the same brightness as Lippmann plates. The same is also valid for chloride. However, the sensitizers ("orthochromatisants") successfully applied to chloride and bromide, did not show any effect on iodide. Concluding this work, it is an pleasant duty to express my appreciation to professor Cotton (directeur du Laboratoire des Recherches physiques à la Sorbonne), for his support and interest. I equally thank my teacher, Mr. de Watteville, who introduced me into the delicate technique of interference photography... etc. =Making your own plates= by Jeff Blythe Diffusion method - estimated cost by Jean (no login) As promise, I post my estimated costs table for a batch of 20 holoplates made with the Jeff Blyth's diffusion method. Silane, LiBr, Pinacyanol come from Sigma-Aldrich All prices are in Euro (1 Euro ~ 0,97 USD) {| border="1" |- !Chemical !Price/Quantity !Diluted quantity !Quant/20 plates !Price/20 plates |- !AgNO3 (6%) |align="right"|18,11/10 g |align="right"|166 ml |align="right"|60 |align="right"|6,55 |- !LiBr (3%) |align="right"|11,2/100 g |align="right"|3300 ml |align="right"|300(*) |align="right"|1,02 |- !Pinacyanol (0,1%) |align="right"|16,81/250 mg |align="right"|250 ml |align="right"|7,5 |align="right"|0,5 |- !Ascobic Acid (1%) |align="right"|2,11/30 g |align="right"|3000 ml |align="right"|300(*) |align="right"|0,21 |- !Gelatin (15%) |align="right"|9/1000 g |align="right"|6666 ml |align="right"|100 |align="right"|0,14 |- !Chrome Alum (2%) |align="right"|3/100 g |align="right"|5000 ml |align="right"|300(*) |align="right"|0,18 |- !Silane (1%) |align="right"|31,16/100 ml |align="right"|10000 ml |align="right"|100 |align="right"|0,31 |- !Glass (4x5) |align="right"|12,5/20 |align="right"| - |align="right"|20 |align="right"|12,50 |} Total for 20 plates - - - 21,41 or 1,07/plate (*) I assume I change for each batch : - LiBr + Dye bath - Chrome Alum hardener - Ascorbic Acid sensitizer But please pay attention of this following note from Jeff about the LiBr bath : "please note that I myself reuse the dye/LiBr baths several times. A little bit of precipitate in the bottom of container (it is only AgBr) can be left there and the liquid poured off or the solution just filtered. So you can make many plates if you want to for the initial expence. The quantity of subbed plates you could make is enough for an industrial production run!" I don't calculate price for water, acetone and methanol because those products are cheap. First batch can seems expensive because you need to purchase relatively big quantity in regard of the used quantity and you need to some laboratory material. Hope this can give you the curiosity to test this easy method. Jean PS : my 2nd batch has failed because I don't care to dry plates enough after Chrome Alum bath! Results was presence of chrome salt who fog the plates. I'll try hardening gelatin with a bath of 1% formalin in DI water. =SM-6= *Sodium Hydroxide 12.0g *Methyl Phenidone 6.0g *Ascorbic Acid 18g *Sodium Phosphate (dibasic) 28.4g *Water to 1L =Stop Bath= *Acetic Acid 20g *Water to 1L =Safe Ferric Brilland Bleach= ( rehalogenating Bleach designed by brilland) *Ferric III Sulfate 30g *Citric acid 30g *Potassium Bromide 30g *Deionized water to 1000 cc. You can use it and store it for a very long time at room temperature. It gives very low noise results. =AAC= *Ascorbic Acid 18g *Sodium Carbonate to give a pH of 10.5 *Distilled Water 1L =AGFA 80= *Metol 2.5g *Soduim Sulfite (anhydrous) 100g *Hydroquinone 10g *Potassium Carbonate 60g *Potassium Bromide 4g *Distilled Water 1L =GP-8= *Metylphenidone .2g *Hydroquinone 5g *Sodium sulfite (anhydrous) 100g *Potassium hydroxide 10.6g *Ammonium thiocyanate 24g *Distilled water 1L Mix 60 ml of developer with 400ml of distilled water. Develop for 6 minutes at 20C. =GP-2= *Metylphenidone .2g *Hydroquinone 5g *Sodium sulfite (anhydrous) 100g *Potassium hydroxide 5g *Ammonium thiocyanate 12g *Distilled water 1L Mix 15ml of developer with 400ml distilled water. Develop for 12 minutes at 20C without agitation. Develop with plate facing up and DO NOT agitate (you don't want to move the disolved silver away from the plate). =CPA1= *Metylphenidone .02g *Hydroquinone .65g *Sodium sulfite (anhydrous) 13g *Potassium hydroxide 1.4g *Ammonium thiocyanate 3.1g *Distilled water 1L Develop for 2 minutes at 22C. 3 seconds of initial agitation. =N6= *Metol .5g *Sodium Sulfite (anhydrous) 100g *Hydroquinone 45g *Sodium carbonate 30g *Potassium thiocyanate 5g *Potassium bromide 10g *Distilled water 1L Mix 1 part developer to 8 parts distilled water. =F1= *Amidol 4g *Sodium sulfite (anhydrous) 30g *Silver nitrate 3g *Potassium bromide 2g *Sodium thiosulfate 45g *Distilled water 1L Develop for 8 minutes. Fix for 2 to 3 minutes. =F2= *Metol 10g *Sodium sulfite (anhydrous) 100g *Silver nitrate 2g *Potassium bromide 2g *Sodium thiosulfate 30g *Distilled water 1L Develop for 30 minutes. No fix is required. =MM-Collo 1= From Martin: The best formula I ever made for a colloidal developer was: *Metol.............................2g *Ascorbic acid.....................7g *Methylphenidone.................0,5g *Potassium bromide.................3g *Potassium carbonate..............20g *Ammonium thiocyanate..............2g *Distilled water...................1L Dilute 1 : 50 or up to 1:100 (with distilled water) On PFG-03M it yielded extremely fine grains, resulting in a yellow emulsion (compared with the orange/red layer produced upon GP development). Development is quite slow, requiring > 30 min @ 20°C. =VR-P developer= *Sodium Sulphite anhydrous 194 g *Hydroquinon 25 g *Potassium Hydroxide 22 g *Methylphenydone 1.5 g *Potassium Bromide 20 g *Potassium Metaborate 140 g *1,2,3-Benzotriazole 0.1 g *Distilled water to 1 L Working solution: 1 part of VR-P Developer + 6 parts distilled water =Phillips' Ferric Nitrate Bleach= *150 g Ferric Nitrate *33 g Potassium Bromide *20 g Glycerol *300 mg Phenosafranine *500 ml Isopropyl *500 ml Distilled Water =Phillips' PBQ-1 Bleach= *2 g PBQ *30 g Potassium Bromide *1.5 g Boric Acid *1L Distilled Water =Phillips' Ferric EDTA= *30 g Ferric Sulfate *30 g Di-sodium EDTA *30 g Potassium Bromide *10ml Sulfuric Acid *1L Distilled water =D-14H= From Hans: I got this formula from http://silvergrain.com/labs/Print_Developer_Recommendation?title=Print_Developer_Recommendation It does not to be mixed in a A and B solution and I have found that it works just as good as the Ultimate safe holographic developer. I made on adjustment to the original formula in that I left the KBr out because I don't think that there should be KBr in a holographic developer. Development time is about 1.5 minutes. *Dimezone S 0.2g *ascorbic acid 6.0g *sodium sulfite, anhydrous 12.0g *sodium carbonate, monohydrate 30.0g *triethanolamine, 99% 5.0ml *salicylic acid 0.5g *water to make 1.0 liter target pH 10.4 ± 0.2 =Ascorbate Developer= But I contend that the best way of dealing with ascorbate developer stock and it is a way we have been successfully using for some years in our labs is to "A and B" it. For A we have a 500ml bottle with: *20g ascorbic acid *3g Metol (4-methylaminophenol sulfate) *and top it up with 500ml deionized water for B we have a 500 ml bottle of *50g sodium carbonate anhydrous *15g sodium hydroxide top up with 500 ml deionized water. (This one should be labeled "very caustic" ) Just use equal volumes of A and B from then on. Now there are 3 bonus points for using Metol instead of phenidone. 1) is that phenidone is quite a strong silver halide solvent and tests have proved that metol gives brighter holograms. 2)The second point is that metol has a hardening action on gelatin and its effect on speeding up the development time over what you would have with just alkaline ascorbate means that even notoriously soft emulsions juch as PFG-03 can be in and out of the developer bath into a stop bath (~5% acetic acid ) in around 20 seconds, before the gelatin is seriously attacked. Assuming of course your exposure level was good enough. 3) Metol is a weaker reducing agent or developer than alkaline ascorbic acid. When Metol gets oxidized it goes really dark brown so this is a useful indicator to tell you when your bath is exhausted because it wont go severely dark until most of the ascorbate has been oxidized. A mild yellowing like weak tea is quite OK . Dont forget to use the floating dish method of 2 closely fitting plastic dishes with the upper dish keeping most of the air out as it floats and acting as convenient agitator as well. Acid ascorbate in the stock soln A will not seriously oxidize for a year. (Slight yellowing is perfectly OK . ) jeff =Metol-Ascorbate developer courtesy of Laser Reflections= The formula is as follows: Metol-Acorbate Developer (Part A + Part B) Part A: Metol 10g Ascorbic Acid 80g Water to 1000ml Part B: Sodium Carbonate Anhydrous 120g Sodium Hydroxide 14g Potassium Bromide 4g Water to 1000ml Use it in combination with a Fe-EDTA bleach - a safe, stable bleach which has a long shelf life. Fe-EDTA Bleach EDTA (2Na) 30g Fe(III) Sulfate 30g Potassium Bromide 30g Sodium Hydrogen Sulfate Crystals 30g Water to 1000ml =Sergey Vorobyov's developer - OD-1= New postby Gall » Mon Nov 08, 2010 12:05 pm Some time ago Mr. Vorobyov invented a developer for silver-halide holograms that does not contain any rhodanides. It is ideal for both beginning and advanced holography. The original Russian article is here: http://www.holography.ru/tech8rus.htm Original formula: *Metol = 2 g *Sodium Sulphite (anhydrous) = 25 g *Hydroquinone = 5 g *Borax B[sub]4[/sub]H[sub]4[/sub]Na[sub]2[/sub]O[sub]7[/sub] = 2 g *Sodium Thiosulfate (photographic fixer) = 6 g *Water = 1000 ml Here sodium thiosulfate replaces rhodanide. It dissolves AgBr so that the process is the physical one and not the chemical one. Simplified formula - made from Kodak D-76, ideal for beginners (image is slightly worse but still works): *Take Metol and Hydroquinone mix from two ready-made 0.5l D-76 packages (2x[1 g + 2.5 g]). *Take Sodium Sulphite and Borax mix from one package (1x[50 g + 1 g]). *Add 6 g (one teaspoon) neutral fixer (Sodium Thiosulfate). This will result in following: *Metol = 2 g *Sodium Sulphite (anhydrous) = 50 g *Hydroquinone = 5 g *Borax B[sub]4[/sub]H[sub]4[/sub]Na[sub]2[/sub]O[sub]7[/sub] = 1 g *Sodium Thiosulfate (photographic fixer) = 6 g *Water = 1000 ml Dissolve Metol and Hydroquinone first in some warm (40-45 centigrades) water, then add everything else, add water to 1000 ml and filter the solution. The resultiong solution should be mixed with water 1:4 before use. Develop around 10 minutes at 18 centigrades. =Zip1= For transmission Holograms. I have been using my own developer for the last three years which is extremely active requiring much shorter exposure times than others (JD-2, JD-4, Pyro, etc). Used it for reflection and transmission on Slavich (especially VPR-M) and Agfa films and plates (8E75/56). Sometimes EDTA and sometimes Dichromates bleaches: Zip1: *Metol 1gr, *Hydroquinone 1gr, *Phenidone 0.5gr, *Sodium Sulphite 30gr, *Ascorbic Acid 10gr, *Potassium Hydroxide 30gr, *water to make 1 litre Dave I've used it for reflections in place of the pyro developer and with the dichromate bleach. It also over comes the hassle of accidently getting stained fingers with the pyro developer if you forget to put the rubber gloves on. The main benefit I've found is that the image brightness is on a par with the other developers with the bonus of shorter exposures. The mix of the Metol, Hydroquinone and Phenidone with the Potassium Hydroxide is quite an active combo. I'm not really surprised and certainly these chemicals are cheaper than pyro and catechol.. 6cadb9f85597c4313be29711a8033f108b907ab5 0 155 1556 158 2013-04-20T22:59:04Z Admin 0 wikitext text/x-wiki == Biological Basis of Vision == ===The Human Eye=== <p>Well-informed expositions on the biology and architecture of the human eye are available online, for example: [http://www.merck.com/mmhe/sec20/ch224/ch224b.html Online Merck Manual]. A broad article is available at [http://en.wikipedia.org/wiki/Eye WikiPedia]. A frequently cited reference on the retina from a neural/functional standpoint is Dowling (1987). The human eye is a direct extension of the brain; much more than a "biological camera," the eye performs pre-computation on observed imagery prior to transmitting it towards the visual cortex. In the words of Churchland and Sejnowski (1993), "[t]he primate retina transforms patterns of light on the 100 million photoreceptors into electrical signals on the mere one million axons in the optic nerve, and the 100:1 compression ratio suggests heavy-duty signal processing and information compression" (p. 148). One striking illusion that highlights visual precomputation, [http://studenthome.nku.edu/%7Edouglask/illusions/MachBands.htm Mach banding], is the incorrectly-perceived brightness at edges of differently-shaded fields. Although still incompletely understood, this may be due to lateral inhibition amongst nearby photoreceptors, resulting in high-pass filtering in the eye itself. ===Relevant Neural Regions=== <p>In general, imagery from the right visual field (as collected by the ''left'' hemisphere of both eyes) is transmitted via the optic nerve and optic chiasm to the left hemisphere's optic tract; likewise, imagery from the left visual field travels along the ''right'' hemisphere's optic tract. We note that most of this flows to the thalamus's lateral geniculate nucleus (LGN), with another pathway to the superior colliculus. The information reaches the visual cortex, which is located at the back of the brain. The visual cortex has several regions: V1, V2, and so on, whose supposed function is beyond the scope of this discussion. However, we note two relevant and generally-supported hypotheses: '''Retinotopic Mapping in V1''' A striking series of experiments showed that regions of the visual cortex are mapped retinotopically to the observed field, that is, "neighboring cells have neighboring receptive fields" (Churchland & Sejnowski, 1994, p. 155). In a seminal experiment performed by Roger Tootell, a primate's brain was examined after fixation on a patterned bullseye-like target - when the brain was stained as a function of activity, an image of the target was clearly visible on the unfolded cortex (Tootell, Silverman, Switkes & De Valois, 1982). See a [http://neuro.med.harvard.edu/site/dh/114.jpg photograph here], from the Harvard website containing David Hubel's online vision textbook. [http://neuro.med.harvard.edu/site/dh/b23.htm section: The Architecture of the Visual Cortex.] '''Regions of V1 and V2 Correspond to Varying Degrees of Monocularity and Binocularity''' Churchland and Sejnowski (1994) state that: "For the brain to generate stereo vision, there must be means for the brain to compare retinal images ''relative to varying planes of fixation.'' Hubel and Wiesel (1963) discovered that striate cortical cells were not uniform in their response to a visual stimulus, but some cells were strongly monocular, and were flanked by other cells responding somewhat to stimuli from both eyes, though preferring one or the other, flanked in turn by cells that were binocular" (p. 197). See David Hubel's [http://nobelprize.org/medicine/laureates/1981/hubel-lecture.pdf 1981 Nobel Prize lecture]. Learn more about the visual cortex at [http://en.wikipedia.org/wiki/Visual_cortex Wikipedia]. == Depth Cues == Humans perceive imagery that falls on their retina(s) as three-dimensional when influenced by one or more ''depth cues.'' Monocular depth cues can be experienced with just one eye; binocular depth cues require two. === Monocular Depth Cues === Briefly, monocular depth cues include: *'''Relative size:''' larger objects are interpreted as being nearer the observer *'''Interposition / Overlapping:''' close objects tend to occlude far objects *'''Linear perspective (foreshortening):''' Receding parallel lines appear to meet at the horizon. *'''Aerial perspective (haze / fog):''' Blurry or foggy objects may be interpreted as distant, since haze usually blurs distant scene elements. *'''Light and shade:''' So-called "2 1/2-D" rendering uses the interplay of shape and light to suggest the three-dimensionality of objects. Note that people assume that light comes from above when viewing an image; this is the so-called ''light-from-above prior'' or ''light-from-above heuristic''. *'''Motion parallax:''' Horizontal observer movement (egomotion) "makes" near objects appear to move faster than distant objects. Note that this cue can be used to simulate egomotion, that is, in movies, animations, and true 3-D representations, moving foreground elements faster than background elements evokes the sensation of movement. *'''Accommodation (focus):''' Retinal focus provides information to your brain about the probable distance from your eye to the object you are fixating on. One issue of non-holographic 3-D displays is the so-called "accommodation / vergence conflict," in which the angular swivel of the eyes does not agree with their focus. This happens, for example, when watching a stereoscopic 3-D movie, since there are cases in which your eyes are focused at a distant screen while they are rotated inwards to gaze at a very close scene element. *'''Texture Gradient:''' As in a field of wheat, the perception of a textured region is a function of distance. A variety of [http://www.sapdesignguild.org/resources/optical_illusions/index.html optical illusions] prey upon the assumptions your mind makes about interpreting monocular depth cues. ===Binocular Depth Cues (Stereopsis)=== The average interpupillary distance is approximately 6-6.5 cm. In normal circumstances, this leads to each eye observing a different 2-D field. The brain interprets these differences for depth information, such as (De Valois & De Valois, 1990): *'''Vergence:''' The angular "swivel" of the eyes while gazing at an object provides a strong cue regarding the depth of that object. *'''Positional Disparity:''' A large-scale illustration of positional disparity is observed by holding one's outstretched index finger and observing the relative motion of your finger and the background when viewed alternately by your left and right eyes. [http://en.wikipedia.org/wiki/Stereopsis Wikipedia: Stereopsis] *'''Phase Disparity of Frequency Components:''' There is evidence suggesting that the brain is sensitive to the phase difference of the frequency components of an image, which has a different magnitude, of course, than displacing the sine wave component itself (De Valois & De Valois, 1990, p. 302) *'''Orientation Disparity:''' Orientation disparity refers, for example, to the different angle a line makes on each retina when gazing at a line pitched toward or away from the observer. *'''Spatial Frequency Disparity:''' The separable existence of this cue may still be in debate. Spatial frequency disparity is the difference in spatial frequency for scene elements that are, for example, at varying depths from the observer (Halpern et al, 1987). For example, pitching a single-frequency grating at an angle to the observer yields different perceived spatial frequencies in each eye (De Valois & De Valois, 1990, p. 307). The collection of potential disparities are called ''stereopsis.'' '''An Implication of Random-dot Stereograms''' Note that the brain does not require local stereopsis to perceive depth; global stereopsis "can occur without monocular contours" (De Valois & De Valois, 1990, p. 314). For example, Julesz's (1971) random-dot stereograms present two views that appear, in a monocular sense, like disorganized spatial noise. However, the brain is able to fuse the two images into a scene containing depth - perhaps via the global low-freqency content in the imagery. ==Guidelines for Effective 3-D Imagery== ===Rules of Thumb for Particular Display Media=== One implication of the preceding discussion is that it is best to match subject matter to the display medium and intended observation environment. Experts in the following media are invited to add their own rules of thumb: * Holographic stereograms * Cylindrical multiplex holograms * Quasi-holographic electro-optical displays ===Bandlimiting Can Decrease Interview Aliasing=== Holographic stereograms and other discrete-"view" 3-D displays can exhibit motion artifacts due to interview aliasing. For example, image points far from the image surface appear to jump to neighboring views during egomotion if they are sampled or reconstructed improperly. Holography researcher Michael Halle (1994) discusses these constraints, which apply in particular to holographic stereograms and non-holographic parallax displays. In short, interview aliasing can be mitigated by intentionally blurring scene elements distant from the image surface. ===Understand Your Medium's Focus Characteristics=== Of course, different 3-D display media use different methods to reconstruct 3-D light fields. For example, some holograms are highly astigmatic, putting the horizontal and vertical foci at very different surfaces in or beyond the 3-D scene. The family of horizontal parallax only (HPO) holograms discards some or all vertical parallax information (De Bitetto, 1968; Benton, 1969; De Bitetto, 1969; Benton, 1977). The long-term effects of viewing astigmatic display media, such as HPO holograms, are not widely known in the display community, and references to thoughtful work in the area are appreciated. While not holographic, the variety of electronic 3-D display technologies also vary in their focus characteristics. They range from volumetric displays, whose true voxels in (''x'', ''y'', ''z'') space elicit proper vergence and accommodation cues (Favalora et al, 2005) to experimental "highly-multiview" HPO systems (Favalora, 2005) and lenticular-sheet displays which are HPO ''and'' typically project very discrete infrequently sampled horizonal parallax information. Members of the former MIT Media Laboratory's Spatial Imaging Group explore the importance of choosing the correct scene-sampling and reconstruction geometries as a function of factors including the intended observation point and propose computational predistortion methods for dealing with these issues (Halle, Benton, Klug, & Underkoffler, 1991). == References == <small> *Churchland, P. & Sejnowski, T. J. (1994). ''The Computational Brain''. Cambridge, Mass.:The MIT Press. ISBN 0262531208 *Benton, S. A. (1969). Hologram Reconstructions with Extended Light Sources, ''J. Opt. Soc. Amer. 59'', 1545A. *Benton, S. A. (1977). White-light transmission/reflection holographic imaging. In E. Marom, A. Friesem, & E. Wiener-Avnear (Eds.), ''Applications of Holography and Optical Data Processing'' (pp. 401-409). *De Bitetto, D. J. (1968, March 1). Bandwidth reduction of hologram transmission systems by elimination of vertical parallax. ''Applied Physics Letters, 12''(5), 176-178. *De Bitetto, D. J. (1969, August). Holographic Panoramic Stereograms Synthesized from White Light Recordings. ''Applied Optics, 8''(8), 1740-1741. *De Valois, R. L. & De Valois, K. K. (1990). ''Spatial Vision''. Oxford: Oxford University Press. ISBN 0195050193 *Dowling, J. E. (1987). ''The Retina: An Approachable Part of the Brain''. Cambridge, MA: Harvard University Press (Belknap Press?). ISBN 0674766806 *Favalora, G. E. (2005, August). Volumetric 3D Displays and Application Infrastructure. ''Computer, 38''(8), 37-44. [http://www.greggandjenny.com/gregg/IEEE_Computer_Favalora.pdf PDF] *Favalora, G. E., Chun, W., Cossairt, O. S., Dorval, R. K., Halle, M., Napoli, J., & Thomas, M. (2005), "Scanning optical devices and systems," U.S. Pat. App. US2005/0285027A1, filed Feb. 15. *Halle, M. W., Benton, S. A., Klug, M. A., & Underkoffler, J. S. (1991). The Ultragram: A Generalized Holographic Stereogram. In S. A. Benton (Ed.), ''Practical Holography V'' [Proc. SPIE-IS&T Electronic Imaging, SPIE Vol. 1461] (pp. 142-155). [http://citeseer.ist.psu.edu/halle91ultragram.html CiteSeer] *Halle, M. (1994). Holographic stereograms as discrete imaging systems. In S.A. Benton (Ed.), ''Practical Holography VIII'' [Proc. SPIE] Vol 2176, (pp. 73-84). Bellingham, WA. [http://splweb.bwh.harvard.edu:8000/pages/ppl/halazar/pubs/discrete_spie94_preprint.pdf Preprint PDF] *Halle, M. (1997, May). Autostereoscopic displays and computer graphics. ''Computer Graphics,'' ACM SIGGRAPH, 31(2), 58-62. [http://web.media.mit.edu/~halazar/autostereo/autostereo.html HTML and PDF versions.] *Halpern, D. L. et al (1987). What causes stereoscopic tilt from spatial frequency disparity. ''Vision Res., 27''(9), 1619-1629. *Hubel, D. H. & Wiesel, T. N. (1963). Shape and arrangement of columns in cat's striate cortex. ''Journal of Physiology, 165'', 559-568. *Julesz, B. (1971). ''Foundation of cyclopean perception''. Chicago: University of Chicago Press. *Okoshi, T. (1976). ''Three-Dimensional Imaging Techniques''. Academic Press. ISBN 0-12-525250-1 *Ratliff, F., Milkman, N., & Rennert, N. (1983). Attenuation of Mach bands by adjacent stimuli. ''Proc Natl Acad Sci U S A 80''(14), 4554-8. [http://radiology.rsnajnls.org/cgi/ijlink?linkType=ABST&journalCode=pnas&resid=80/14/4554 Abstract and Article PDF] *Shepherd, G. M. (2003). ''The Synaptic Organization of the Brain''. Oxford University Press. ISBN 019515956X *Tootell, R. B. H., Silverman, M. S., Switkes, E., & De Valois, R. L. (1982). Deoxyglucose analysis of retinotopic organization in primate striate cortex. ''Science, 218'', 902-904. </small> == External Links == * H. Kolb et al, ''[http://webvision.med.utah.edu/ Webvision: The Organization of the Retina and Visual System]'', John Morgan Eye Center, University of Utah (accessed 28 May 2006) * [http://www-staff.lboro.ac.uk/~mmtw/holopaperWeb.pdf Brief Survey on Three-Dimensional Displays: from Our Eyes to Electronic Hologram] 5370ad31621b255093d46fedee62327b54fad7d1 0 156 1558 160 2013-04-20T23:02:51Z Admin 0 wikitext text/x-wiki == Holography Glossary == [[A|A]],[[B|B]],[[C|C]],[[D|D]],[[E|E]],[[F|F]],[[G|G]],[[H|H]],[[I|I]],[[J|J]],[[K|K]],[[L|L]],[[M|M]],[[N|N]],[[O|O]],[[P|P]],[[Q|Q]],[[R|R]],[[S|S]],[[T|T]],[[U|U]],[[V|V]],[[W|W]],[[X|X]],[[Y|Y]],[[Z|Z]] ---- *'''Aerial perspective''' - the distance or depth effect caused by atmospheric haze. Haze creates a large amount of extraneous ultra-violet light to which all photographic emulsions are sensitive. *'''Acetic acid''' - chemical used for stop baths and to acidify acid fixing solution. *'''Acetone''' - solvent chemical used in certain processing solutions that contain materials not normally soluble in water. *'''Albumen paper''' - printing paper invented by Blanquart-Evrard in the mid-19th century where egg whites were used to coat the paper base prior to sensitization. The albumen added to the brightness of the white base and substantially improved printed highlights. *'''Allegory''' - work of art that treats one subject in the guise of another. An allegoric photograph usually illustrates a subject that embodies a moral "inner meaning". *'''Alum''' - chemical used in acid hardening fixing baths. *'''Aluminum compounds''' - groups of chemicals often used as hardeners in fixing baths. *'''Ambrotype''' - Mid-19th century photographic process introduced in 1851-52 by Frederick Scott Archer and Peter Fry. It used weak collodion negatives which were bleached and backed by a black background which produced the effect of a positive image. *'''Amidol''' - soluble reducing agent which works at low pH values. *'''Ammonium chloride''' - chemical used in toners and bleachers. *'''Ammonium Dichromate''' - chemical used as a sensitizer in Dichromated Holograms. *'''Ammonium persulfate''' - chemical used in super-proportional reducers. *'''Ammonium sulfide''' - pungent but essential chemical in sulfide or sepia toning. *'''Ammonium thiosulfate''' - highly active fixing agent used in rapid fixing solutions which works by converting unused silver halides to soluble complexes. *'''Amphitype''' - Mid-19th Century process based on an underexposed albumen-on-glass negative. This was viewed by reflected light against a black background to give a positive image similar to a ambrotype. *'''Anaglyph''' - result of forming stereoscopic pairs from two positives each dyed a different color, usually green or red. *'''Antiscreen plates''' - photographic plates containing dyes that reduce the blue sensitivity. Used unfiltered, they can give results similar to those obtained with yellow filtered orthochromatic plates. *'''Apodization''' - lens treatment designed to cut down diffraction fringes that appear around the images bright points of light. *'''Aquatint''' - etching technique allowing control of tonal areas to produce almost unlimited gradations from pale gray to black. Because of this it has also been used in photography as an alternative term for gum bichromate process. *'''Argentotype''' - Mid-19th century silver print process, on which the kallitype and sepia paper processes are based. *'''Aristotype''' - early commercial print type made on collodion-chloride or gelatin-chloride paper. *'''Azo dyes''' - compounds forming colors of great strength and purity. Used in camera filters and integral tripack dye-bleach materials. 1d09e9643d46e8717e91e7b87f7787799f50b87f 0 160 1564 168 2013-04-20T23:09:13Z Admin 0 Created page with "*BS - Beam Splitter *DE - Difraction Efficiency *DMD - Digital Micro-Mirror Device *EASLM - Electrically Addressed Spatial Light Modulation *H1 - A first generation hologram …" wikitext text/x-wiki *BS - Beam Splitter *DE - Difraction Efficiency *DMD - Digital Micro-Mirror Device *EASLM - Electrically Addressed Spatial Light Modulation *H1 - A first generation hologram *H2 - A hologram of a hologram (copy) *H3 etc. - Sucessive generations of holograms *HOE - Holographic Optical Element *LASER - Light Amplification by Stimulated Emission of Radiation *l - liters *''l'' - length *LCD - Liquid Crystal Display *m - meters *''m'' - mass *M1, M2, M3 etc. - Mirror 1, Mirror 2, Mirror 3, etc. *mJ/cm^2 - milliJoules per centimeter squared *RH - Relative Humidity *SBR - Single Beam Reflection *SBT - Single Beam Transmission *SF - Spatial Filter *SI - International System of Units *SLM - Spatial Light Modulator *TEA *uJ/cm^2 - microJoules per centimeter squared *" - Inch = 25.4 mm *' - Foot = 12 inches Also see the [[Holography Glossary]]. '''From Sergio on the Forum''' Some post recommendations internationally acept: SI writing style * Symbols do not have an appended period/full stop (.) unless at the end of a sentence. * Symbols are written in upright (Roman) type (m for metres, l for litres), so as to differentiate from the italic type used for variables (m for mass, l for length). By consensus of international standards bodies, this rule is applied independent of the font used for surrounding text.[10] * Symbols for units are written in lower case, except for symbols derived from the name of a person. For example, the unit of pressure is named after Blaise Pascal, so its symbol is written "Pa" whereas the unit itself is written "pascal". All symbols of prefixes larger than 103 (kilo) are also uppercase. o The one exception is the litre, whose original symbol "l" is unsuitably similar to the numeral "1" or the uppercase letter "i" (depending on the typeface used), at least in many English-speaking countries. The American National Institute of Standards and Technology recommends that "L" be used instead, a usage which is common in the US, Canada, Australia (but not elsewhere). This has been accepted as an alternative by the CGPM since 1979. The cursive ℓ is occasionally seen, especially in Japan and Greece, but this is not currently recommended by any standards body. For more information, see Litre. * The SI rule is that symbols of units are not pluralised, for example "25 kg" (not "25 kgs").[10] o The American National Institute of Standards and Technology has defined guidelines for American users of the SI.[11][12] These guidelines give guidance on pluralizing unit names: the plural is formed by using normal English grammar rules, for example, "henries" is the plural of "henry". The units lux, hertz, and siemens are exceptions from this rule: they remain the same in singular and plural. Note that this rule only applies to the full names of units, not to their symbols. * A space separates the number and the symbol, e.g. "2.21 kg", "7.3×102 m2", "22 K".[13][14] Exceptions are the symbols for plane angular degrees, minutes and seconds (°, ′ and ″), which are placed immediately after the number with no intervening space. * Spaces may be used as a thousands separator (1 000 000) in contrast to commas or periods (1,000,000 or 1.000.000) in order to reduce confusion resulting from the variation between these forms in different countries. In print, the space used for this purpose is typically narrower than that between words (commonly a thin space). * Any line break inside a number, inside a compound unit or between number and unit should be avoided, but if necessary the latter option should be used. * The 10th resolution of CGPM in 2003 declared that "the symbol for the decimal marker shall be either the point on the line or the comma on the line". In practice, the decimal point is used in English and the comma in most other European languages. * Symbols for derived units formed from multiple units by multiplication are joined with a space or centre dot (·), for example "N m" or "N·m".[15] * Symbols formed by division of two units are joined with a solidus (⁄), or given as a negative exponent. For example, the "metre per second" can be written "m/s", "m s−1", "m·s−1". Only one solidus should be used, i.e. "kg·m−1·s−2" is preferable to "kg/m/s²", and "kg/m·s²" is something else. Many computer users will type the / character provided on computer keyboards, which in turn produces the Unicode character U+002F, which is named solidus but is distinct from the Unicode solidus character, U+2044. * In Chinese, Japanese, and Korean language computing (CJK), some of the commonly used units, prefix-unit combinations, or unit-exponent combinations have been allocated predefined single characters taking up a full square. Unicode includes these in its CJK Compatibility and Letterlike Symbols subranges for back compatibility, without necessarily recommending future usage. * When writing dimensionless quantities, the terms 'ppb' (parts per billion) and 'ppt' (parts per trillion) are recognised as language-dependent terms since the value of billion and trillion can vary from language to language. SI therefore recommends avoiding these terms [1]. However, no alternative is suggested by the International Bureau of Weights and Measures (BIPM). e294984b54e84f9d2db4e60b3d11ee2d9a938006 0 161 1568 170 2013-04-20T23:10:18Z Admin 0 Created page with "First of all great thanks to Bill Jensen – without his works on SSY1 I wouldn’t catch pulsed laser bug. Thanks Bill  Here is some information about my homebuilt pulsed las…" wikitext text/x-wiki First of all great thanks to Bill Jensen – without his works on SSY1 I wouldn’t catch pulsed laser bug. Thanks Bill  Here is some information about my homebuilt pulsed laser. I named it YAGna (polish girl’s name, if you visit Poland most of our highlander’s daughters will be Jagna ). YAGna uses SSY1 Nd:YAG laser capable of giving 170mJ; 4ns; 1064nm pulses. It wasn’t built for taking portraits – rather for shooting small objects (insects, splashes, falling drops of quicksilver or Ga-In alloy). Right now I’m running SSY1 just above lasing threshold (2*230V*sqrt(2) = 644V at main cap, which gives something like 6,7J of energy). For two reasons – I’m still using original polymer q-switch which is delicate, at this power level both flashlamp and KTP will last forever. And at lower energy levels beam quality is better (I hope there is less unwanted longitudinal modes). At 6,5 J I get up to 38mJ of IR, after conversion and filtering unconverted IR (a filter from a dead VHS camcorder) I have 8-15mJ of 532nm light. YAGna is equipped with Brewster window to increase conversion efficiency. Conversion efficiency is low since KTP is not working near its destruction limit. It is better for the crystal. [[image:SSY1a.jpg]] YAGna standing on her 3 BLACK legs  Tika looking suspiciously at YAGna. Originally there was a rebreather inside the box (used in coal mines). [[image:SSY2.jpg]] Front side of the laser. A diverging lens, piezoelectric lighter on top (for firing flashlamp) and 3 wing-nuts for adjusting the tilt of KTP crystal. The case is sealed with black electrician’s tape (the tape is black, not the electrician ) to prevent the optics from dusting. [[Image:SSY3.jpg]] Inside YAGna. From left to right – KTP kinematic mount (rotation + tilt), pulse forming network, SSY1 laser on its breadboard, voltage doubler (based on 2 microwave oven HV capacitors and 2 HV diodes), 24V power supply (for PFN1s vacuum relay – after depowering the main capacitor is discharged) and an aligning laser (which ceased to work after 20-30 shots – maybe 0,1% of IR coming out from HR was sufficient to destroy the diode after focusing). As you cans see there is still plenty of room inside, so an amplifier stage, additional PFN1 and trigger board will fit. Case dimensions are something like 30x20x10cm. [[Image:SSY4.jpg]] Diverging lens, KTP mount, PFN1 network and SSY1 laser. The lens is slightly off-line to avoid backreflections (or rather because there were some problems with gluing ) [[Image:SSY5.jpg]] KTP mount. The crystal is glued inside brass block with thermoconductive glue. There is a 5mm tungsten iris in front of 5x5x5mm KTP crystal. [[Image:SSY6.jpg]] SSY1 Nd:YAG laser. Attached to a breadboard using magnets. [[Image:SSY7.jpg]] Beam shape after diverging. Photo was take before I mounted the tungsten iris. Since now I was shooting small (up to 4x3cm) test holograms (at 6,5J), but I got a holo showing entire face profile from Bill (taken at 15J). You can see some of my holos at YouTube: *http://youtube.com/watch?v=6U9ebkGEtl4 *http://youtube.com/watch?v=d4XoRhb9SOg *http://youtube.com/watch?v=LhR24W8M_aA Approximate cost of YAGna so far is around $400 (KTP acosted $250). I think minimalist’s version of YAGna (KTP salvaged from a dead DPSS pointer) could cost below $200. What I’d like to improve in YAGna: * add amplifier stage(s) – 2 SSY1s are already waiting to be used. * add spatial filter (1m focal length, 0,5mm DIY tungsten pinhole). * add trigger board and a laser photogate to make holograms of splashes. * divide YAGna in two – laser head and PSU on separate boxes. * make YAGna portable to make holograms outdoors. * whatever else imagination allows ca0663f9597c2a83a8da6c9ad6a48e4474488062 0 162 1572 172 2013-04-20T23:11:54Z Admin 0 Created page with "Holograms can be made with no mathematics. However, there is a mathematical basis for all of holography. Below we will explore the mathematical basis for holography. *[[Holograp…" wikitext text/x-wiki Holograms can be made with no mathematics. However, there is a mathematical basis for all of holography. Below we will explore the mathematical basis for holography. *[[Holography Transmission Equations Part I]] by Ed Wesly *[[Holography Transmission Equations Part II]] by Ed Wesly *[[The Calculus of Holography]] 9803c7a3a87196f932c8a745bc8d9e9f1c129359 0 168 1584 184 2013-04-20T23:15:05Z Admin 0 Created page with "[[Sneaky Fish]] by Jeff Blyth" wikitext text/x-wiki [[Sneaky Fish]] by Jeff Blyth dca874f2dad612d5707d3961b50d354bbb8721ba 0 170 1588 188 2013-04-20T23:16:59Z Admin 0 Created page with "[[http://www.anamarianicholson.com/ Anna's Web Site]]" wikitext text/x-wiki [[http://www.anamarianicholson.com/ Anna's Web Site]] f6bd52d29c8f2d410b070d90cd8b8218163113b6 0 172 1592 192 2013-04-20T23:22:10Z Admin 0 Created page with "==What is Art?== This is the age old question artists and critics have bantered around since before writing. Leo Tolstoy wrote an essay about it called [[What is Art?]]. "A larg…" wikitext text/x-wiki ==What is Art?== This is the age old question artists and critics have bantered around since before writing. Leo Tolstoy wrote an essay about it called [[What is Art?]]. "A large part of the beauty of a picture arises from the struggle which an artist wages with his limited medium." - ''Henri Matisse'' "Art is a man made object that is created to release an emotion from the artist and to invoke an emotion in a viewer." - ''Colin Kaminski'' A very informative treatment can be found in Maragret Benyon's [http://www.holonet.khm.de/benyonarchive/writings/gram.htm Holography as Art] ==The Hologenic Object== ==Composition== ==Lighting a Hologram== ==Fitting a Hologram into Your Decor== e499de4788c318d78f1097b254664c59e84c83f8 0 203 1622 254 2013-04-20T23:26:57Z Admin 0 Created page with "=Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]]…" wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Daguerreotype''' - first practical and commercial photographic process, introduced by Louis Daguerre in 1839. The sensitive material comprised silver iodide, deposited on a polished silver plated copper base. A positive image was produced by camera exposure and mercury "development", which turned light struck halides gray-white. The image was made permanent by immersing the plate in a solution of sodium chloride. *'''Daylight enlarger''' - early type of enlarger using light from a hole in a window to provide illumination of the negative. *'''Desensitizing''' - reducing an exposed emulsion's sensitivity to light. This can be done by the application of dyes or by using oxidation agents *'''Developer''' - chemical bath containing reducing agents, which converts exposed silver halides to black metallic silver, making the latent image visible. *'''Development''' - process of converting exposed silver halides to a visible image. *'''Diazo''' - abbreviation of diazonium compounds, which decompose under the action of intense blue or ultraviolet radiation, forming an image in an azo dye. *'''Dichroic filters''' - produced by metallic surface coatings on glass to form colors by interference of light. Used in high quality color enlarger heads. *'''Dichroic fog''' - purple-green bloom usually seen on negatives and caused by the formation of silver in the presence of an acid. *'''Dilution''' - reduction in the strength of a liquid by mixing it with an appropriate quantity of water. *'''Dimensional stability''' - substance's ability to remain unchanging in size when subjected to processing and drying. *'''Dish development''' - method of development used for processing single sheet, cut film or paper by immersing in a shallow dish of developer and agitating by rocking the dish. *'''Documentary photography''' - taking of photographs to provide a record of social and political situations with the aim of conveying information. *'''Dodging''' - control of exposure in photographic printing achieved by reducing exposure to specific areas of the paper. *'''Dry down''' - refers to the amount a print darkens after drying. *'''Dry mounting''' - method of attaching prints to mounting surfaces by heating shellac tissue between the mount and the print. *'''Dye destruction process''' - method of producing a colored image by partially bleaching fully formed dye layers incorporated in the sensitive material. *'''Dye-image monochrome films''' - black & white negative films designed for color processing. *'''Dye sensitizing''' - defined as all silver halides used in black & white emulsions are sensitive to blue light. Early photographic materials possessed only this sensitivity. *'''Dye transfer print''' - method of producing color prints via three color separation negatives. Negatives are used to make positive matrixes, which are dyed in subtractive primaries and printed in register. *'''Dynamism''' - picture structuring which relates to a sense of movement and action. c3bcfd352678a446fc65f2898137171316f51e4b 0 213 1648 274 2013-04-21T00:23:01Z Admin 0 Created page with "(For details and setup examples, see the [[Holography_Technology]] page.) (For a more technical description see [[Holograms]].) ===Comparison=== ===Single Beam Reflection=== …" wikitext text/x-wiki (For details and setup examples, see the [[Holography_Technology]] page.) (For a more technical description see [[Holograms]].) ===Comparison=== ===Single Beam Reflection=== Also called a Denisyuk Hologram this is the most common first hologram. It is fairly easy to set up and can be viewed in white light. This type of hologram is one of the least expensive as there are minimal optics and the stability requirement can be minimized by touching the plate to the object. ===Single Beam Transmission=== This is actually easier than a Single Beam Reflection however since it requires a laser for viewing it is not as common. The depth of field shown is often much better. This type of hologram is one of the least expensive as there are minimal optics and the stability requirements can be minimized. ===Split Beam Reflection=== This hologram is also known as an off-axis reflection hologram, or a "straight reflection" hologram. The laser beam is split into two beams with an partially mirrored beamsplitter, which can be mounted on a variable slide. One portion of the divided beam is spread with lenses or diffusion glass to illuminate the object, set in front of the holographic recording medium. The other portion of the laser is spread through a lens array or spacial filter, then reflected off of a collimating mirror, which is directed at the back of the hologram-to-be at the reference angle. The reference angle is determined by: practicality in the optical set-up; Bragg's angle and the frequency of the recording laser; and the angle of the intended viewing light; with a range of 38 to 46 degrees giving good interference fringes. The reference angle will become the illumination angle of view for the finished hologram. Steering mirrors are needed to complete this set-up. This type of hologram can be more expensive to produce as there are additional optics needed and more stringent stability requirements. It can be much brighter than a Single Beam Reflection. It can also contain relatively vast parallax. Depth is limited as in a Denisyuk hologram. (Image plane reflection holograms offer greater depth and projection possibilities, but their parallax potential is not as great as in a straight reflection hologram) ===Split Beam Transmission=== This is the most common way to make a transmission hologram. It requires a beamsplitter and is most often used to make an H1 for copying. This type of hologram is going to be more expensive as there are additional optics needed and more stringent stability requirements. ===H1 to H2 Copies=== This is making a copy of a hologram. It is a more complicated set up requiring a beamsplitter and a good Master Hologram (H1). It allows the hologram to bisect the film plane with some of the scene in front of the plate and some behind. ===Rainbow Transmission=== This is a special case of an H2 copy. It is a transmission hologram made by masking the master hologram (H1) to a horizonantal slit. It is viewable in white light but the color changes with viewing position. ===Multiplex=== This is a very complicated set-up and has to do with storing many close views or perspectives of an object onto a single holographic plate in the form of slits. Then those slits are imaged to the same relative location in space creating a focused, multi perspective image. A hologram is then made of the combined image projections creating 3 Dimension hologram. ===Holographic Optical Element (HOE)=== [[HOE]]s are holograms that work like optical elements (mirrors and lenses). ===Computer Generated=== By computing the interference patterns, it's possible to simulate a hologram in software. The result when printed to a transparency using a standard printer is usually low resolution and inefficient, but can work. [http://www.medcosm.com/prog_CGHmaker.htm MedCosm CGH Software (free)] 1c484e93050b235220e2a934d50f62d67da75f00 0 214 1650 276 2013-04-21T00:24:06Z Admin 0 Created page with "Diffusers can be used to soften the shadows from the object beam for softer lighting effects. From a artistic lighting standpoint, a laser is considered a point source. To make s…" wikitext text/x-wiki Diffusers can be used to soften the shadows from the object beam for softer lighting effects. From a artistic lighting standpoint, a laser is considered a point source. To make softer lighting we need to widen the beam source. There are many ways to do this: *Broken Light Bulbs *Sandblasted Glass *Etched Glass *Glass or Plastic sanded in one direction only Commercial diffusers are also available. You can specify how much diffusion you need. A 10% diffuser allows most of the light to pass through. A 30% diffuser spreads more of the light. It should be remembered the diffusers also randomize the polarization. This can increase the fog level of the hologram. It is very important the the diffuser be shielded from the plate so no stray light can hit the plate directly. 6e44e0963f146faceb94e1b252097284ca471e95 0 216 1660 280 2013-04-21T00:24:44Z Admin 0 Created page with "Here is a [http://rudieberkhout.home.mindspring.com/SPIE-Acompactdisplay.htm Great Article] by [[Rudie Berkhout]]." wikitext text/x-wiki Here is a [http://rudieberkhout.home.mindspring.com/SPIE-Acompactdisplay.htm Great Article] by [[Rudie Berkhout]]. 6b5aa76d08fa381cbff069d05f01573eaa8c5fb3 0 228 1676 304 2013-04-21T00:33:23Z Admin 0 Created page with "==Some Uses for Everyday Items in Holography== by John Pecora Here are some tips for saving money on ‘lab’ equipment. It is surprising how many everyday objects can be use…" wikitext text/x-wiki ==Some Uses for Everyday Items in Holography== by John Pecora Here are some tips for saving money on ‘lab’ equipment. It is surprising how many everyday objects can be used to good effect in holography. These are just suggestions. Please remember that it is your responsibility to pay attention to safety, and use common sense. *Heating pads used with three or more settings can be used as adjustable heaters for processing trays. Simply put the heating pad under the tray and turn the pad on to the desired setting. *Black foam board can be used for blocking stray light. The type that is black throughout is best as the edges stay black even when they are cut. This material can also be used for making an iris. *A shutter can be made from most old 8mm movie cameras. They have a low voltage electric shutter. Remove this unit and set up a circuit with the original voltage of the camera, and a switch. *A thick piece of glass, 1/4 inch or thicker, can be used as a beam splitter. Using the thick piece of glass allows a small piece of electric tape to be placed over the glass to block the secondary reflection off the back. *Sandwich boxes can be use as processing trays and also as storage for the chemistry without having to pour the liquids back into bottles after each session. They come in many sizes and shapes with airtight lids. Store sealed containers with chemicals in a dark, dry, cool place when not being used. *Rubber inner tubes can be used as the dampening mechanism between a holographic table and the support legs. *A slab of granite can be used as a holographic table. *Most old overhead projectors contain large front surface mirrors and large Fresnel lenses. They can be purchased at yard sales and flea markets for just a few dollars. *Most photocopiers and fax machines contain front surface mirrors. *New Jefferson Nickels have a weight of 5 grams and new Lincoln Pennies have a weight of 2.5 grams. Standard paper clips have a weight of 1 gram. To verify the weight of the paper clips put a nickel on one side of the balance and find 5 paper clips of the same size that equals the nickel. These can be used on a balance for measuring out chemicals. *A hair dryer can be used to dry a piece of holographic film or plate after processing. Drying intensity and heat is variable with very inexpensive dryers. *Polarizers can be found in polarizing sun glasses. These can be used to adjust the intensity of polarized laser light by inserting the polarizer in the beam path and rotating. They can also be used to check the polarization of light at different locations in an optical set-up. *Two pieces of window pane glass and binder clips can be used to sandwich a piece of holographic film. This will hold the film rigid and flat. *A microwave can be used to warm the deionized or distilled water needed for mixing up processing chemistry. But please be careful to keep chemical-contaminated containers separate and secure. One method is to heat the water in a clean container in the microwave and then pour it into the chemical container for mixing, always keeping the clean container free of any chemicals. *Two-part, fast-hardening epoxy is great for securing two pieces of metal without the need for drilling and tapping. This also allows easy disassembly with just a small sharp blow to one of the pieces. *A pinhole can be made by sandwiching 5 or 10 pieces of aluminum foil together and poking with a pin while the pile is on a hard piece of rubber. Each piece of foil will have a slightly different size of pinhole. *Automobile windshield wiper blades can be used as a squeegee. If you epoxy two blades to a pair of scissors then, when the scissors are closed 3/4 of the way, you can squeegee both sides of the film at the same time. For plates this is not necessary as you can do one side at a time with a single blade. *Clothes pegs on a line can be used to hang up films to dry. After clamping the film at two corners with the pegs, clamp two more at the bottom corners as weights to keep the film straight while drying. *Dishwasher drying agent can be in place of PhotofloTM in the final rinsing bath. Use an agent that does not have fragrance and, preferably, one that is clear. *Sodium carbonate can be purchased cheaply as a chemical for increasing the pH of swimming pools and spas. *Sodium bisulfate can be purchased cheaply as a chemical for decreasing the pH of swimming pools and spas. *Sulfuric acid can be purchased as car battery acid. Most formulas call for concentrations that are lower than that sold as auto battery acid. *Black Sanford Sharpie markers, which come in different sizes, are ideal for blackening optics, mounts and anything small you want to reduce reflections on. They are permanent markers that write on almost anything. *Paper MateTM liquid paper correction is great for painting objects for holography. It dries to a flat white and diffuses the light very well. *A disposable shower curtian works well as a dust protector for a collimation mirror. 7786db734b8859669e36d67d493727a3dcaa1903 0 477 1784 1105 2013-04-21T01:10:34Z Admin 0 Created page with "==Bleaching with Rehalogenating Bleach== by Jeff Blyth A successful bleach for reflection Holograms comes from using: '''60KB Rehalogenating Bleach''' *40g Ethylenediaminetetr…" wikitext text/x-wiki ==Bleaching with Rehalogenating Bleach== by Jeff Blyth A successful bleach for reflection Holograms comes from using: '''60KB Rehalogenating Bleach''' *40g Ethylenediaminetetraacetic acid iron (111) sodium salt [Aldrich cat. No. 35,961-0] *60g. potassium bromide & *70 ml acetic acid Dissolved up in 1 litre water (tap water is OK here). This bleach is particularly good after a developer such as [[TJ1_Developer]] is used. ===Theory=== So what happens with in this type of bleach used WITHOUT FIXING (i.e. without removing unexposed AgBr) in thiosulfate, is that the developed up silver gets re-oxidized to AgBr. But instead of returning you to square one and leaving you with a uniform coating and distribution of AgBr again just as it was before you exposed it, it is energetically more favorable for the re-made AgBr to move over to the adjacent dark fringe made up of virgin AgBr and grow onto that dark fringe using the virgin AgBr grains as seeding centers. That actually requires the bleach solution to have some AgBr solvation ability to enable this carry-over effect to occur. This effect occurs with the help of the relatively high concentration of potassium bromide present because it does raise the solubility of AgBr in the solution through the formation of complexes. Now the great thing about this carry-over effect is that it causes almost all the original Ag in the emulsion to build up the fringes whereas if you had had to use fix you would have removed about half of your original silver content in the thiosulfate solution. A revealing experiment is to take a newly developed plate that has been in a stop bath of ~5% acetic acid, rinse it and then place it upright in a beaker so that it is half covered in a fix solution such as 20% sodium thiosulfate. After giving it gentle agitation over about 4 -5 minutes avoiding splashing the unimmersed half it is then all given a vigorous rinse under tap water. Then the whole plate is immersed in the above bleach formula and given constant agitation. The first interesting thing that will be seen is that the fixed half will take longer to bleach the dark silver than the unfixed half . This is at first counter-intuitive since one would expect that initially removing the undeveloped AgBr in the fix would later have left the bleach plenty of spare room in the gelatin to react and oxidize the silver metal without being encumbered by lots of AgBr still present. The second point that will be noticed is that when the whole plate is bleached there will be considerable scatter on the fixed half compared to the unfixed half. The increased scatter in the fixed half also testifies to the truth of that carry-over mechanism. The scatter is a consequence of the carry-over effect being unable to operate because of the missing virgin AgBr. Therefore the newly formed AgBr builds up around the dissolving silver grains in solution before reaching a level where it becomes energetically favorable to precipitate out. The precipitate will be in larger grains and to some extent will occur in the dark fringe areas where the gelatin is supposed to be free of AgBr in order to give good fringe contrast with the new AgBr in the light fringes. The finished hologram if it had been recorded in red will now be shifted to the green, scattery, and less bright than the unfixed half. ===Bleaching Transmission Holograms=== The formulation above has been found to work pretty well also with transmission Holograms (Hs). The not-so-good thing about it though is that the original sensitizing dyes become chemically locked into AgBr grains making the emulsion very vulnerable to print out, i.e. darkening slowly in ambient lighting, particularly sunshine. The dyes can be chemically inactivated with a 2% potassium or ammonium dichromate bath-- it takes about a minute after you have used the Ferric EDTA bleach. ===A Good Bleach for Transmission Holograms, (can also be used to make reflection ones with a shorter replay wavelength)=== A better bleach for transmission holograms is to dissolve up 0.5 to 1 gram of iodine crystals in about 200 ml alcohol (methanol or ethanol) and then about 200ml of water is added. However before putting the plate in, it is essential this time to use fix. This is because the bleach has no carry-over power. The fix bath can be 20% sodium thiosulfate and the plate given about 4 minutes in it with mild agitation. It is then given a thorough rinse under tap water to remove all traces of fix. After the bleach step the iodine stain can be removed in a 70% alcohol bath. A very good point about this bleach is that the dyes are released by the fix and easily removed in the alcoholic iodine solution. A comparison was made by cutting a developed and stopped (5% acetic acid) transmission H in half and then bleaching one half in the ferric-EDTA bleach and the other half after fixing was put in the iodine bleach. The iodine bleached half finished up producing a slightly higher diffraction efficiency. (This could be due to the carry-over effect being less efficient in the larger fringe spacing of transmission Hs compared to reflection Hs.) If you choose to use this bleach on say a '''reflection hologram''' made with a red laser then you can get a quite nice final yellow-green replay color because contraction occurs due to loss of the original virgin AgBr in the fix solution. (You also get a little bit of expansion due to AgI replacing AgBr.) It may then look brighter than a red one would have looked because of the eye's extra sensitivity to light-green even though some valuable AgBr diffracting material has been lost ===References=== P. Hariharan, C.M. Chidley; Rehalogenating Bleaches for photographic phase holograms 2: spatial frequency effects. Appl. Optics. 27 No.18, 3852 (1988) 9d345f99fe9fb8067684c1a27b0856e7549f6bb7 0 478 1788 1107 2013-04-21T01:13:56Z Admin 0 Created page with "==The Reversal Bleach system== by Jeff Blyth The most popular form of this type originally used dichromate salt and sulfuric acid. It has been of particular value for use on t…" wikitext text/x-wiki ==The Reversal Bleach system== by Jeff Blyth The most popular form of this type originally used dichromate salt and sulfuric acid. It has been of particular value for use on the AGFA 8E75 HD plates and film because when used correctly it can produce the lowest levels of light scatter. Its popularity for Denisyuk reflection holograms made with 633nm from HeNe lasers also comes from the inclination to hit the fairly elusive yellow replay coloration due to the right amount of emulsion shrinkage. I consider that its chief asset today with finer grain materials available is as a bleach for transmission holograms. It has good printout resistance (i.e. low tendency to darken in ambient lighting over time) and can produce high diffraction efficiency. However for Denisyuk reflection holograms it does not achieve as much diffraction efficiency as can be obtained from a good rehalogenating bleach. People using it have however failed to appreciate that the developer used beforehand should not contain silver halide solvents such as sodium sulfite and urea, and the need for the rigorous exclusion of halide contaminants as discussed in the Theory section. A suitable developer for use in conjunction with this bleach is [[TJ1 Developer]]. The proportions used in the formulation is hugely tolerant of variation. I have chosen to use a lower concentration of dichromate compared to previous publications because it leaves the bleached hologram with less yellow coloration from the dichromate salt and this means less rinsing is required to remove it. Increasing the dichromate proportion will reduce the time taken to bleach the dark silver. I have substituted sulfuric acid with the more manageable solid salt sodium hydrogen sulfate. (This is in fact a semi-neutralized form of sulfuric acid). The basic formula is: *1 g. potassium dichromate (or ammonium dichromate) *10g sodium hydrogen sulfate. *made up to 1 litre in distilled or de-ionized water. The set up should include 2 baths of de-ionized water (DI) as follows: '''Bath 1''' *DI with *4% acetic acid (Acts as a “Stop” to stop developer action) '''Bath 2''' *DI '''Bath 3''' *Reversal Bleach ==Procedure== #After development, a brief 10 second rinse under running tap water then a good rinse in Bath 1. for ~1 minute . #A good rinse in Bath 2. ~1 minute #Immerse in Reversal bleach (Bath 3) and gently agitate until no dark silver remains #Important- after the bleach bath the hologram should be put first back in DI (Bath 2) for ~ 20 sec. before being rinsed under tap. ==Theory== The idea might seem simple enough, after development the developed up silver is dissolved up into the solution and removed from the gelatin film so that then leaves the undeveloped virgin AgBr in the dark fringes to make the hologram. So in effect it both “fixes” and bleaches. The good point about it is that it has a high resistance to printout or darkening in ambient light and can have low scatter levels with holographic plates that do not have the smallest AgBr grains such as the old Agfa material, the lowest scatter comes about provided you understand what you must do to stop any soluble halide ions getting into your hologram before you have finished processing. ==Developer considerations== Because of the way this bleach operates, particular consideration has also got to be given the developer system used first. It is not satisfactory to have any “physical development “ which encourages silver bromide to be dissolved in the developer. We need to have as much virgin AgBr as possible to create our final diffraction and it makes no sense to load up the developer with sulfite ion­ a weak silver halide solvent and similar remarks apply to urea as in the CW developer. The amount of development is also more important than in the case of the rehalogenating bleach system. Since all the developed silver is going to be washed away, if you develop too much for too long then you start to eat into your virgin AgBr in the dark fringes because even unexposed AgBr is developable given enough time. The consequence is that reflection holograms made with red lasers may look a dull green instead bright yellow/green due to increased contraction . This effect has also been shown to cause a peak in the graph of diffraction efficiency vs. developer/exposure level and after the peak the efficiency drops away. Whereas when a rehalogenating bleach is used after the same developer conditions, the diffraction efficiency flattens off. [Joly] ==Importance of De-ionized rinsing water.== After the developer the hologram needs a good rinse under tap water to remove the developer and soluble bromide and iodide ions in it . Even if the developer had no halide ions initially, the development process means that the AgBr and AgI in the emulsion had to be broken up and turned into dark silver and soluble Br- and I-. The tap water rinse then leaves the emulsion with just chloride ions from tap water which are less of a problem to deal with later than soluble bromide or iodide ions. Before the dichromate bath is used you have to have two pre-baths of de-ionized water (DI) to remove all traces of dissolved halide ions. If you don’t do this then some of the developed up silver fails to be removed from the light-struck fringes and deposits itself back in the fringe as silver halide. This causes scatter in the finished hologram and reduces diffraction efficiency because the light struck fringes have failed to be properly cleared of AgBr . Where even experienced holographers commonly go wrong is that after removing the bleached hologram from this reversal bleach bath, they rinse it under the tap instead of first putting the hologram back in de-ionized water for a second time . This is because after leaving the bleach bath the hologram is full of silver ions in solution which can instantly form silver chloride particles with the chloride ions in tap water. So this causes scattering from inside the emulsion which cannot be wiped away even if surface silver chloride can be. After using the bleach bath you may notice a red-brown precipitate or scum in the bath. This is normal and it is actually good to have it in there. It is made up of silver chromate or dichromate which is not very soluble but is far more soluble than are the silver halides. So what this red sludge means is that your bleach bath is saturated with silver chromate in solution and any stray halide ions in solution are effectively precipitated out before they can get inside your emulsion. Even though some precipitated silver chromate may form in your gelatin layer it comes out easily in the DI bath. After this final DI bath you can then rinse the hologram in tap water to eliminate any dichromate ions if you wish, because there will be no soluble silver ions to cause trouble in a final tap water rinse. (Personally I like having a trace of dichromate in the hologram not washed out because it helps to prevent future printout. However dichromate is quite poisonous and who knows what future use your hologram may be put to particularly with young children around). ==Tap water rinsing== Prolonged tap water rinsing can remove some of your AgBr with significant differences depending on time of year and the temperature of your cold water supply. Any AgBr loss causes a shift to a shorter wavelength replay in the case of reflection holograms and of course some loss in diffraction efficiency but sometimes people prefer to simply shift the color from orange-yellow to yellow-green using a hot water rinse. The result can look brighter, also any scatter from AgCl contamination can be removed because AgCl is about ten times more soluble than AgBr. Some idea of the temperature effect can be seen from this graph: [[Image:SilverSolubility.gif]] ==References== [Joly L., Jacobs P. Spectral Response of reflection gratings on Holotest 8E75 HD Proc. Int’l Symp. on Display Holography, ed. Jeong, T.J. Lake Forest College IL. Vol III p115-126 (1989).] [Owen, B.B. and Brinkley, S.R. J.A.C.S. 60, 2237 (1938).] 387b973b40add32c17b90b2a0254f4a6c87726ad 0 491 1798 1133 2013-04-21T01:18:03Z Admin 0 /* Glass Plate Method 2 - O-Ring (Standard Epoxy) */ wikitext text/x-wiki DCG holograms are very sensitive to re-adsorbing moisture. If a hologram disappears after bieng in humidity you can usually get the image back by reprossing the hologram in alcohol drying baths. If you want to make sure the hologram is permanent you will need to seal the back side. The two most common methods are to seal the back with a glass plate or to coat the back with a cyanoacrilate adhesive. Most art holographers use the glass plate method. == Glass Plate Method 1 - Full Coverage (UV Epoxy) == When sealing a hologram with the glass plate method it is important to scrape at least 3mm of gelatin off the edge all the way around the hologram. This insures that the edge of the gelatin is sealed. Once this is done the epoxy is spread evenly over the entire emulsion and a glass plate is place over the sealant. The entire sandwich is place over or under a UV light (black light) to cure. This sealant is bought to have the same index of refraction of glass and should dry clear. This sealant can be expensive. If you wish to make your own UV sealant see Jeff Blyths "Do It Yourself" UV sealant below. == Glass Plate Method 2 - O-Ring (Standard Epoxy) == An economical approach that works very well is to use 5 minute two part epoxy (at any hardware store). Scrape 3mm of gelatin off the edge all the way around as indicated above as best as you can. Clean the glass cover plate. Mix the two parts of the two part epoxy as directed on the epoxy label. I use a q-tip cut in half and a piece of scrap glass. Once the epoxy is mixed use a tool, like the q-tip rod to evenly spread a bead of epoxy around the scraped 3mm area on the hologram. Place the cover plate on and insure there are no place missing any epoxy by visually inspecting it. Place on level surface and let dry. '''Here is a post from Jeff Blythe on making UV cure epoxy at home:''' ===A DIY UV sealant=== In keeping with the grand DIY philosophy of the Forum I thought I would put down some basic ingredients for making your own out of materials which are fundamentally cheap because of their big industrial use. However before that a hypothesis that fits observations I have made. I believe that the reason DCG has been so notoriously difficult to seal up and prevent moisture getting in is not necessarily due to any fault of hydrophobic glues being somehow rather more moisture pervious than expected. I believe the real trouble has been that sandwiched between 2 glass sheets the gelatin layer contracts with age and builds up a significant vacuum. This results eventually in outside air getting through microcracks inspite of diligently thick glue having been applied around the edges of the sandwich.. This contraction effect might be just to do with the basic properties of the gelatin under prolonged lighting but it could well be more to do with the final stubborn traces of water /alcohol still hanging about and alcohol vapour can very gradually (we can be talking “years” here) make its way through the edge sealant increasing the vacuum effect. Anyway whatever the cause an obvious way to minimise it is to put the newly processed DCG in a really dry warmer I am not sure what temperature is best but 60-70C for as long 24 hours seems to work or alternatively I have left them in a really effective desiccator for a week. Then without giving the ultra dry DCG a chance to re-absorb ambient humidity a dry glass cover plate with dry sealant can be put on. This topic has been discussed on the forum before and some of you guys have had vastly more experience than me at sealing. To make a UV curable sealant,you need a monomer, crosslinker, and free radical generator for UV. Monomer : Methyl methacrylate or better (more hydrophobic) is butyl methacrylate (NB. Not tert-butyl methacrylate) Crosslinker: Ethylene dimethacrylate (alternative silly name by Sigma Aldrich is ethylene glycol dimethacrylate). UV sensitizer (free radical generator in UV.): DMPA or dimethoxyphenyl acetophenone. One can use about 1 part DMPA to 100 parts monomer to 5-10 parts crosslinker. It gets harder the more crosslinker you add of course. (~80-100% crosslinker just cracks up). But the mix has initially a rather low viscosity , lower than the commercial stuff. It is a good idea to store mixture over silica gel in a fridge in the dark. Jeff 8beff968c4c1100b33a5da98fe5e3b2ff3964cb1 0 503 1810 1157 2013-04-21T01:33:48Z Admin 0 Created page with "Described here are sucessful chemistries to use for each qualifying film for a particular type of hologram. For specific formulations look at [[Silver Processing Formulas]]. ==…" wikitext text/x-wiki Described here are sucessful chemistries to use for each qualifying film for a particular type of hologram. For specific formulations look at [[Silver Processing Formulas]]. ===Single Beam Transmission - Film vs Chem=== ====PFG-01==== For low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up. (Ed Wesly) ===Single Beam Reflection - Film vs Chem=== ====PFG-01==== (Ed Wesly)- Replay in the same wavelength use CWC2 developer with PBQ rehalogenating bleach (Ed Wesly)- Replay is color shifted use Pyro or CWC2 developer with Dichromate reversal bleach Replay in same color use JD3 - Integraf Replay shorter use JD2 - Integraf ====PFG-03==== (Ed Wesly)- Replay is same wavelength use Slavich Hardener with G2 Developer and Slavich Fixer ====BB640==== (Ed Wesly)- Replay in the same wavelength use Pyrogallol based developer with Rehalogenating bleach ===H1 Transmission - Film vs Chem=== ====PFG-01==== (Ed Wesly) - Replay in the same wavelength use CWC2 developer PBQ rehalogenating bleach Another case is for low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up (Ed Wesly). ===H2 Transmission - Film vs Chem=== ====PFG-01==== Another case is for low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up (Ed Wesly). ==H2 Reflection - Film vs Chem=== ====PFG-01==== (Ed Wesly) - Replay in the same wavelength use CWC2 developer PBQ rehalogenating bleach (Ed Wesly) - Replay is color shifted Pyro or CWC2 developer Dichromate reversal bleach ====PFG-03==== (Ed Wesly)- Replay is same wavelength use Slavich Hardener with G2 Developer and Slavich Fixer ====BB640==== (Ed Wesly)- Replay in the same wavelength use Pyrogallol based developer with Rehalogenating bleach 8ee217c442cc654f7fcb6e6a3aa0e5dfc394e0a8 0 520 1830 1191 2013-04-21T02:16:55Z Admin 0 Created page with "==TJ1 Developer== by Jeff Blyth '''Part A''' *6g Metol (4-methylaminophenol sulfate) *1 litre deionized water Dissolve up first then add:- *40g. Ascorbic acid (vitamin "C")…" wikitext text/x-wiki ==TJ1 Developer== by Jeff Blyth '''Part A''' *6g Metol (4-methylaminophenol sulfate) *1 litre deionized water Dissolve up first then add:- *40g. Ascorbic acid (vitamin "C") '''Part B''' *100g sodium carbonate anhydrous *30g sodium hydroxide *1 litre deionized water. (This one should be labeled "very caustic" use rubber gloves and eye protection --guard against splashing at all.) Just use equal volumes of A and B with the "floating dish" method. (2 close-fitting plastic dishes are arranged so that one floats ontop of the other which contains the developer. The volume in the lower dish should be just enough to give a minimal air gap so that the uptake of oxygen is minimised and the top dish can be used as a rocker to agitate developer over a plate. Development time:- This developer is intended to react fast (to keep the silver grains spheroidal rather than filamentary, and to minimize damage to the gelatin in the strongly alkaline solution). So sufficient exposure level to give a development time of only 15-30 seconds should be aimed for . ==Notes== Developer's lifetime with the floating dish method can be days, depending on usage. A yellow or mild brown color means the developer is still good. When the developer is very dark brown or black it should be discarded. ==How this developer is thought to operate== ''The ascorbate ion with lots of alkalinity around (Na hydroxide /carbonate) is a powerful reducing agent that gets oxidized by light-damaged AgBr grains to "dehydro-ascorbate" and black or brown Ag metal grains are produced.But ascorbate ions with their negative charge are slowed from approaching the Ag+ ions in the lattice of the grain because each Ag+ is surrounded by a barrier of about 6 oppositely charged Br- ions. in the latticework, which is most often in the cubic form. (AgBr crystals can be structurally like the familiar cubic NaCl crystal , each Na+ being surrounded by 6 Cl- ions and each Cl- ion is surrounded by 6 Na+ ions ).The negative Br- ions in the lattice repel the easy access of the negative ascorbate- ions.. However “metol” is a reducing agent which is a sulfate salt and is therefore positively charged. These positive reducing ions can pass rapidly through the negative Br- lattice barricade and start reducing the Ag+ to uncharged silver metal and causing the Br- lattice ions to go into solution. But the ascorbate ions are slightly more powerful reducing agents than the metol ions so that causes newly oxidized metol ions to get returned to their original reduced form by the ascorbate ions. Therefore the metol acts as a catalyst for the ascorbate developer because it may be only momentarily oxidized.. Only when much of the ascorbate has got oxidized, do the metol ions really start to stay oxidized and oxidised metol is nearly black whereas oxidized ascorbate is merely yellow-brown. This has the useful bonus of causing the developer to get increasingly dark and this therefore acts as an indicator that it is becoming exhausted . When the developer is virtually black and opaque it means that most of the ascorbate has been oxidized and the solution should be discarded. ( Slight darkenening means the developer is OK still) . --- Another bonus about metol seems to be that it has an instant slight hardening action on soft gelatin as can be found from doing a fingernail scratch test on the notoriously soft Slavich PFG-03 emulsion after say 15 seconds immersion in “TJ1” developer made up with and without metol.'' aa793dec9a3153a6c8b79d3f7e5e092cf99e4e6d 0 571 1836 1293 2013-04-21T02:21:40Z Admin 0 Created page with "==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and Dichromated Gelatin (DCG) ho…" wikitext text/x-wiki ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and Dichromated Gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300nm long and 1.5nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape(2,3,4,5,19). If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties(6,7). These two images were taken from source (16). [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion(6,8,9). Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions(13,14). Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom(13,14). This image was taken from source (16). [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them(10,12). Research is needed using vitamin C with CrVI(11). ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII (15). During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram(15). The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://en.wikipedia.org/wiki/Collagen # http://www.britannica.com/eb/article-72553/protein # http://www.lsbu.ac.uk/water/hygel.html # http://www.stanford.edu/~spark7/ # http://en.wikipedia.org/wiki/Gelatin # http://www.lsbu.ac.uk/water/hygel.html # http://albumen.stanford.edu/library/c20/kozlov1983.html # http://www.greatlakesgelatin.com/gelatin%20information.htm # http://www.cdc.gov/niosh/topics/hexchrom/ # http://en.wikipedia.org/wiki/Hexavalent_chromium # http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/ # http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf # http://www.gelatin-gmia.com/index.htm # Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora # http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html # http://sandwalk.blogspot.com/2007/02/collagen.html d160f1235e10b3722fb72aed06636be597a1b7ea 0 577 1844 1305 2013-04-21T02:29:00Z Admin 0 Created page with "===Troubleshooting=== So you made a hologram! But it is either not perfect or not even visible. Don't despair. We all have made holograms that are blank or have issues. I am goi…" wikitext text/x-wiki ===Troubleshooting=== So you made a hologram! But it is either not perfect or not even visible. Don't despair. We all have made holograms that are blank or have issues. I am going to run down the list of mistakes I have uncovered. For tips on troubleshooting DCG specific problems see [[Troubleshooting DCG]]. For some tips on variables see [[DCG Variables]]. ====Image Missing==== Motion or improper developing. Card left in the object beam or reference beam after checking beam ratios. ====Image Missing parts==== If the object is missing parts then the object was in motion during exposure. If the film is missing views then that portion of the film was in motion. Air bubbles in the index matching fluid will cause this problem. ====Image "Drippy"==== This is caused by soft emulsions and/or excessive pressure during squeegeeing. ====Image Dim==== Under or over exposure. Motion of the bench or film. Beam ratios wrong. ====Image has Rainbow Lines==== Light entered the edge of the plate and bounced between the two surfaces. Make sure to block any light entering the edges of the plate during exposure and reconstruction. ====Image has Circular Patterns (Bull's eye)==== Dust under film when laminated to the backing plate before exposure. ====Reflection Hologram Blurry==== It is normal to only have 4 inches of usable depth. The actual depth is related to how narrow of a bandwidth you are using for reconstruction. If you are looking for greater depth adjust your development to narrow the reconstruction bandwidth. There will be a corresponding decrease in brightness. In an H2 set-up it can be the object beam was too bright. As measured at the film plane the object can not be brighter than the reference beam. ====Image has Black Lines on the Object==== Object moved slightly. [[Image:ObjectMove1.jpg]] As you can see the piece of paper under the kitty moved causing the large black lines. ====Entire Image has black lines on it==== Laser changed frequencies during exposure (mode hop) or is running in two lines. ====Image Flashes at Extreme Viewing Angles==== Laser beam was reflecting off something on the table and reaching the plate. It is important to card off any stray light from the beam. ====Image has Black Lines on the Plate.==== The plate was moving during exposure. ====Plate is Completely Dark==== Overexposed. Fogged film. ====Plate won't Turn Dark in the Developer.==== Underexposed. Old chemistry. Forgot to add part B for 2-part developer. ====Image Flashes Rainbows from a Specific Location==== This spot is too bright/overexposed. If the object is very shiny try spraying with a flatting spray. Flat clear lacquer works if you can't find flatting spray. Rotating the polarization of the object beam with a 1/2 waveplate can turn off shiny parts of the object. Use a polarizer rotated to coincide with the reference polarization to view the object illumination as you rotate the 1/2 waveplate. ====The image has black spots on the Emulsion==== This is called burnout and is most common in image planed H2 copies. It can be corrected by: # Composition, and pre-visualization of the location of the recording plane of the transfer (H2) within it, # Cighting of the scene when making the master (H1) so as to avoid the highlights near the intended transfer plane, # Possibly manipulating the polarization of the scene lighting to reduce the highlights, # Setting the beam ratio by measuring the "object" light in the transfer recording plane at the location of the burn spots (which are easy to find by placing a card in the plate holder) and with a detector about the same size as an average burn spot, # Using a beam ratio and exposure time that gives optimum performance at the location of the burns, and # Using a processing regime that doesn't shrink or swell the emulsion as a function of beam ratio or exposure intensity. ===Diagnosing the Problem=== Once you have identified the cause it is important to figure out exactly what corrective action will help. Motion This is one of the most common problems. To find out if you are stable it is useful to make an [[Interferometry#The_Michelson_Interferometer|Interferometer]]. ===Pictures of Defects=== [[Image:Drippy.jpg]] Here is a hologram that is "drippy" or has "rainbow lines". It was caused by laser light entering the edge of the plate during exposure. Either design your plateholder to block light entering the edges of the plate or tape the edge off with electrical tape. [[Image:Woodgrain.jpg]] This hologram shows "woodgrain". It is caused by the laser light reflecting back and forth from the front to the back of the plate. Make sure you have the corect polarization of the reference beam and make sure the reference angle is somewhere near 54 degrees (Brewsters Angle). [[Image:ObjectMovement2.jpg]] This hologram shows the difficulty of making a hologram of paper. Here the paper moved, either because it was not trapped tightly enough or because it was changing humidity durring exposure. [[Image:PlateMovement.jpg]] Here is a hologram showing plate movement. The dim spots do not change based on view point. [[Image:UnderExposed.jpg]] This hologram was underexposed. You can tell it is under exposed because it is dim and it is even dimmer at the edges where there was less light. If the edges were brighter then you would suspect over exposure. [[Image:BurnOut.jpg]] This hologram shows "Burn Out". The little finger is very reflective and was placed too close to the film plane. You can see the black smear above the finger tip. 0b5db09cfda8c23092dd88e116615c8bd3335374 0 219 1666 286 2013-04-21T05:53:30Z Admin 0 /* Seting up a drill press */ wikitext text/x-wiki ==Drilling a hole in a drill press== *Layout the position of a hole with a scribe. *Mark the exact hole position with a punch. *Drill large holes by predrilling a hole matching the diameter of the web of the drill bit. *Choose the correct speed for the size hole and the material being drilled. *When in doubt use slow speeds and strong feeds. *Smaller holes require quicker speeds and lighter feeds. *Back holes in soft materials with another piece of material to prevent "Blowout". ==Setting up a drill press== *There should be only the smallest amount of play when trying to move the chuck back and forth by hand. *Make sure when drilling through work that the drill bit can not come in contact with the table. *Use a piece of 1/2" drill rod in the chuck with a square to measure the table for squareness. *Setup holes so the minimum amount of quill extension is required for drilling a hole. ==Speeds and Feeds== *Steel *Aluminium *Soft Wood *Hard Wood ==Safety== *Never leave the key in the chuck while changing drill bits. *Never wear gloves while holding work in a drill press. *Always try to hold down work by bolting it to the table or by using a vise. *Always use eye protection when using a drill press. *Unplug or remove the dafety key when chaning drill bits. *Never allow the chip fromed by drilling a hole to grow larger than 1 inch. If the chip starts to become a string relax pressure on the feed until the chip breaks off. fe9f68b4f2dc78e0fd23a88ad00678bd3b81d436 0 819 1634 2013-04-21T06:07:05Z Admin 0 wikitext text/x-wiki == Weird DCG Recipes == 3.6-30-467, Chromium Acetate, Ethanol Markova, Nazarova, and Sharlandjlev, “Control of the Spectral Position of DCG Reflection Holograms,” Institute of Optical Materials and Technology. *64.3 g gelatin, Bloom strength of 210 *7.71 g ammonium dichromate *0.64 g chromium acetate *65 ml C2H5OH (ethanol) *Distilled water to make 1000 ml Plates are coated with the solution at 50°C by doctor-blade method to 20 µm. 5-30-200, Ammonium Nitrate Bahuguna, Beaulieu, and Arteaga, “Reflection display holograms on dichromated gelatin,” Applied Optics, volume 31, issue 29 (1992). *2.5 g of ammonium dichromate *1.5 g of ammonium nitrate *100 cc of distilled water *Heated to 70°C *15 gm of USP grade Baker's gelatin (125 bloom strength) powder slowly added while stirring Spin-coat at 100 rpm the still ~70°C emulsion for 90 seconds under hot-air gun. Dry vertically in a dark box. Plates are ready after about 6 hours. Sensitivity was reported as 100 mJ/cm2 at 488 nm. [In Rallison’s Thick DCG paper, he associated ammonium nitrate with hardening.] 4.5-30-500, Ammonia Coblijn, Alexander B., "Theoretical background and practical processing techniques for art and technical work in dichromated gelatin holography", SPIE Institute Series Vol. IS 8 (1990). *100g water *6g gelatin *0.9g ammonium dichromate *2ml ammonia 35% (added last) Household ammonia is typically 5-10%. [Presumably, the ammonia inhibits the dark reaction.] DCG Notes The basic formula for dichromated gelatin is water plus gelatin plus either ammonium or potassium dichromate. The amounts of each ingredient influence the characteristics of the result. Exposure energy requirements, color shift, emulsion thickness, etc., are all impacted by the formulation. It is convenient, then, to have a standard for formula reference. Richard Rallison promoted using a system of three numbers to describe a formula—grams of dichromate, grams of gelatin, and grams (milliliters) of water. For example, 8-30-250 would be the notation for a recipe consisting of 8 grams ammonium or potassium dichromate, 30 grams of gelatin, and 250 grams of water. To make comparisons among formulae, the gelatin number is always 30 in Rallison’s notation. The three numbers can be scaled equally up or down for producing different quantities of emulsion. (Personally, I usually scale the numbers to 7.1 grams of gelatin, 7.1 grams being the mass of gelatin in quarter-ounce packet of Knox brand gelatin.) Thickness and Bandwidth The ratio of gelatin to water affects the viscosity of the emulsion, and that in turn affects the typical thickness of emulsion on the glass plate. The thickness influences the bandwidth of the final hologram. Rallison reported the following results for emulsions applied by 80 RPM spin coating method: Formula Thickness Bandwidth xx-30-350 5 – 6 µm 50 – 150 nm xx-30-250 8 –9 µm 10 – 50 nm xx-30-200 10 – 12 µm 10 – 50 nm xx-30-150 20 – 24 µm ~8 nm Replay Color Shift The ratio of dichromate to gelatin influences the color shift. The following table has typical values for exposures taken at 514 nm: Formula Color Shift 3-30-xxx 630 nm 6-30-xxx 590 nm 10-30-xxx ~514 nm Exposure Sensitivity My personal guess at typical exposure requirements for the basic recipe 8-30-300 emulsions. Wavelength Exposure 405 nm 5 mJ/cm2 442 nm 15 mJ/cm2 475 nm 40 mJ/cm2 488 nm 60 mJ/cm2 514 nm 125 mJ/cm2 532 nm 200 mJ/cm2 A great many factors may have a dramatic effect on sensitivity, notably humidity and temperature, so the above table is only a point of reference. Sensitivity also varies inversely with the dichromate concentration—halving the amount of dichromate would double the exposure requirement, for example. <br> General Notes “Control of DCG and non-sliver holographic materials”, SPIE volume 1600, International Symposium on Display Holography, 1991. Using 8-30-350 emulsion, exposed at 75% RH and 80 F. Wavelength Sensitivity 441 nm &lt;1 mJ/cm^2 488 nm 4 mJ/cm^2 514 nm 50 mJ/cm^2 532 nm 100 mJ/cm^2 7.6. Sensitizer- We normally use ammonium dichromate crystals or for redder reds Potassium dichromate but the most sensitive of the dichromates (up to three times) is Pyridine dichromate. We don't use it because of its shorter life and difficult preparation. The addition of ammonium nitrate can make the dichromate several times more sensitive, but decreases the useful life and blue shifts the image. Approximate ammonium nitrate concentrations are usually in a ratio of 1 to 5 by weight to ammonium dichromate up to a maximum of 1 to 1 . When the additional substance is washed out of the gelatin a net shrinkage occurs which amounts to a blue shift in reflection holograms and lays down Bragg planes in transmission holograms. <br> by Joe Farina&nbsp;» Wed Aug 08, 2007 11:53 am There is also a paper in SPIE Institute Series Vol. IS 8 (1990) called "Theoretical background and practical processing techniques for art and technical work in dichromated gelatin holography" by Alexander B. Coblijn. This is an unusual but interesting paper based on practical experience. It is kind of an "independent viewpoint" of DCG based on holographic testing, and is not just an empty rehash of things previously published. Anyway, he used the following DCG formula: • 100g water • 6g gelatin • 0.9g ammonium dichromate • 2ml ammonia 35% (added last) I'm not sure what the concentration of ordinary household ammonia is, but that's what the above sounds like. I didn't notice a specific explanation regarding the inclusion of the ammonia, presumably it lowers the pH and increases sensitivity as Jeff explained. Formula Characteristics xx-30-350 Thickness after spinning at 80RPM: 5-6um. Bandwidth: 50-150nm. xx-30-250 Thickness after spinning at 80RPM: 8-9um. Bandwidth: 10-50nm. xx-30-200 Thickness after spinning at 80RPM: 10-12um. Bandwidth: 10-50nm. xx-30-150 Thickness after spinning at 80RPM: 20-24um. Bandwidth: ~8nm. 3-30-xxx Replay: 630nm from 514nm exposure. 6-30-xxx Replay: 590nm from 514nm exposure. 10-30-xxx Replay: ~514nm from 514nm exposure. Holography: A Practical Approach. Ackermann and Eichler. Page 193. Plates prepared from 7% gelatin built up on a spin table to 10-20um then dried are then sensitized in a 5% ammonium dichromate solution for 5 minutes. Wavelength Sensitivity 442 nm 10 mJ/cm^2 475 nm 80 mJ/cm^2 488 nm 100 mJ/cm^2 514 nm 250 mJ/cm^2 My personal guess at typical exposure requirements for typical 8-30-300 emulsions. Wavelength Sensitivity 405 nm 5 mJ/cm^2 442 nm 15 mJ/cm^2 475 nm 40 mJ/cm^2 488 nm 125 mJ/cm^2 514 nm 200 mJ/cm^2 DCG formulae Red-- mix 3-30-250 using Potassium Dichromate spin on at 80-90 RPM, expose single beam 90-100 mj\cmE2 @ 514 if RH = 60% and T = 70 F. Process: develop 5 min., rinse, 30 sec in 1HAB @ 120 F and .86 SG. Dry with slow pull from LHAB followed by hot air. Color should be bright Red-Orange. Rallison’s recipe for red(-der) holograms: 200:30:3. Less AmDi = redder result. Less light = redder result. IPA:water ratio of first bath and bath duration. Longer = greater shift. Richard D. Rallison, Ralcon Development Lab 1.3 Serendipity Back to the story, I returned to Hughes with one of Mike's broken 8 x10 inch dichromates determined to produce my own, Mike was not about to share more of his tricks of the trade so I was on my own. I coated Knox unflavored gelatin "Jello" on glass plates in my apartment using a record player built into an old steamer trunk. The dichromate processes described in the literature by Shankoff, Lin and Chang were all too time consuming to suit me. Mike had suggested during a phone conversation that I mix in all the sensitizing dichromate before coating to save some time and that helped. Everything I made initially came out milky white until I accidentally dropped an exposed plate into Milton's hardening fixer prior to soaking it in water. It was only in the fixer for 30 seconds but that proved to be sufficient to harden it enough to take the shock of hot alcohol without precipitation. A short process was immediately at hand. From then on I could make coatings on any glass surface in 5 minutes, expose them in another 5 minutes, process them in another 5 minutes and seal them up in less than 5 minutes. I immediately produced a few boxes full for show and tell and then lit the lab on fire. I managed to keep that trick under my hat until 1982, when Fred Unterseher persuaded me to publish it. I inadvertently also sold it to Steve McGrew (Holosonics) in 1979 and thought he might make it public just as I was selling it to IBM, but he never did publish. What he did publish was a very fine paper on color control in DCG in 1980, one of the first papers useful to artists working in color at the time. My method of controlling the color and clarity of master holograms was not disclosed til 1985. I dropped a developed broadband hologram into a certain bath that was about 75% alcohol and when I retrieved it and dipped it in hot dry alcohol it came back as a low scatter blue hologram. From that day in Nov 1975 I had a fast, tunable way to make bright masters that added almost no noise to the copies and so I finally had all the processes I needed to start making masters and churning out thousands of bright "dichromates" for sale. Which is what I did. 1b1f81ae7df9d524ff5b86ef48e5502a8f4cb629 0 817 1626 2013-04-21T06:27:22Z Admin 0 wikitext text/x-wiki == Introduction == Ralston introduced a notation for basic recipies for dichromated gelatin emulsions. He use a sequence of three numbers that indicated the quantities of dichromate, gelatin, and water, respectively, used in the formulation. For example, 5-30-200 in Ralson's scheme meant 5 grams of dichromate with 30 grams of gelatin and 200 grams (exactly equivalent to ml) of water made up the recipe. The normal for Ralston's notation was 30 grams of gelatin, while the dichromate and water ratios were allowed to vary. Many amateur holographers use common food-grade gelatin in their work. Knox Gelatin is the most typical. In the United States, Know Gelatin is available in convenient 1 oz. packets. An ounce is roughly 14 grams, so it can be convenient to express Ralston recipes using a 14 gram reference for gelatin instead of the more common 30 grams. &nbsp;Common Ralston recipes then become: {| width="200" |- | Ralston Recipe | Rescaled Recipe |- | 5-30-250 | 2.3-14.250 |- | 10-30-600 | 4.4-140200 |} 9bb2229edaa188026d0ea29ec668260ad1855f0d 0 844 1778 2013-04-21T21:40:03Z Admin 0 /* Bandwidths and color */ wikitext text/x-wiki == Refrigeration == DCG stores well at low humidity in a refrigerator or freezer but containers must prevent contamination, condensation, freezer burn and frost which can all destroy surface quality. Film of 10 to 20 microns or more store best and are good for at least a year. At room temperature and 50% RH, thin films are good for a few hours, thick films typically last a week or more. The addition of a small quantity of TMG to the mixture will greatly increase storage time at room temperature by increasing the pH. == Light bulb as an alternative to the fixer == Developing is simply a process of reducing the remaining chromate ions and thereby uniformly hardening the gelatin. Too much hardening will give a clean, clear but weak and green result. Too little hardening will leave the hologram milky and weak and reddish or yellowish. Development is done either optically or chemically using fluorescent or incandescent lamps or any suitable reducing agent or tanning solution. [Rallison used either Kodak fixer or a 100W lamp at 6 inches from the hologram, for time periods of between 5 and 15 seconds. But he was also exposing at 441nm which would do a much better job than 532nm. By the way, I use the light bulb immediately after the dark reaction (before swelling with any water). I've used Knox gelatin with exposure at 457nm, and this is usually hard enough by itself to require neither fixer nor light bulb.] == Film codes == The film mixtures vary in dichromate and gelatin percentages. The variations depend on the specific use that a DCG film plate has. The film code currently used contains three numbers. The first being the gram-weight of the ammonium dichromate, the second being the gram-weight of the gelatin, and the third being the gram-weight (mis) of the water to be used in the film mixture. (Usually mixed in a 500 ml poly bottle.) The code for film used in broadband image holograms is 8-30-350. Thus, 8 grams dichromate, 30 grams gelatin, and 350 grams (ml) of water are mixed together. The mixture code for "red" holograms is 3-30-200. Most holographic optics are made in 10-30-250 to 8-30-150. In using the film code for a variety of mixtures, the 30-gram gelatin weight number always remains constant. Thus, when a thicker emulsion is desired, the water number decreases. And when more absorption is desired, the dichromate number increases, an increase in thickness narrows the bandwidth and an increase in dichromate shifts the color toward the blue. As a general rule, thicker emulsions require longer process times but are easier to make uniform. The dichromate concentration determines light absorption and the center reconstruction wavelength of the hologram. For higher dichromate concentrations, the increased absorption produces larger gradients of index modulation. Lower the dichromate concentrations produce more uniform index modulations. Larger gradients yield slightly larger bandwidths and the removal of higher percentages of dichromate during processing results in thinner and thus bluer holograms. When a specific bandwidth is desired, along with a specific reconstruction wavelength; it is best to experiment with various film mixtures. Usually starting with a standard mixture and then adjusting the thickness, and dichromate content to achieve the desired results. The color controllability and uniformity of DCG film improves with thicker film emulsions. Consequently, they are more forgiving in their exposing and developing parameters. Extremely thick (25 micron) emulsions (X-30-150, a 5 to 1 water-to-gel ratio) are difficult to use. They are prone to excess bubbles, premature jelling, film pits, low viscous flow, increased impurities and during processing sometimes pull up off the substrate. == Ageing and thickness == The film is ready for exposure after it has been aged an hour or so for a 350 mixture or a day later for a 150 mixture. The addition of 1 or 2 ml of TMG will extend the useful room temp life of 350 film to a day or two and will make 150 film last for several weeks in a 21 degree C, 50% RH environment. The thicknesses of the commonly used mixtures after spinning at 80 RPM and after processing are as follows: 350 yields 5-6 microns, 250 yields 8-9 microns, 200 yields 10-12 microns, 150 yields 20-24 microns. == Bandwidths and color == The relative bandwidths run from 50 to 150 nm for 350 film, depending on processing used. 250 and 200 film make 10 to 50 nm bandwidths depending on processing and 150 film can get down to 8 nm but also runs as high as 30 nm. The color of a film made from a 3-30-200 mixture is around 630 nm when shot at 514 nm. The color of 6-30 film is around 590 for a 514 shot and a 10-30 mixture will easily be tuned to play back at the same wavelength it was shot at. [[Category:Rallison]] [[Category:DCG]] 80c9e16ea493e759b84c865af46a199cd458c2a5 0 804 1560 2013-04-21T21:47:50Z Admin 0 wikitext text/x-wiki [[Category:DCG]] [[Category:Beginner]] [[Category:Pecora]] By: [[John Pecora]] (Note: as this is an original article please do not edit it unless you are John. Please use the discussion page to comment on this work.) ==Abstract== <p>As the availability of green lasers becomes cheaper and more widespread, so does the potential for one to make their own dichromated gelatin (DCG) film and holograms. The purpose of this paper is to provide a basic step-by-step set of procedures such that the beginner may have success in producing their own DCG film and making simple DCG Holograms. There are many variables in the fabrication and processing which alter the aesthetics of a DCG hologram, most of which will be beyond the scope of this paper. And the basics here will not guarantee a professional quality hologram but will lead the reader down one correct path to successfully make DCG film and DCG holograms. It will be up the reader to take the next steps to perfect the quality and repeatability of the DCG hologram process. == Introduction == <p>DCG emulsion is made from a simple solution of ammonium (or potassium) dichromate, raw gelatin and water. Exposure to the DCG emulsion is done in the Green or Blue with higher sensitivity to the shorter wavelengths. Processing is simply a soak in Standard Photographic Fixer followed by a soak in water followed by a dehydrating process in one or more alcohol concentration baths. As a DCG hologram is susceptible to image loss when exposed to moisture, the DCG hologram will be sealed. There is a multitude of ways to perform each of these functions and the ones presented here have been tried and prove to work but may not be the best or suit a particular application for the DCG hologram. <p>'''Also, it is very important to insure safety at each step of of the process using good chemical safety practices, knowledge of the chemicals and equipment being used, proper disposal of chemicals, and common sense.''' It is not within the scope of this paper to point out safety hazards and it is the responsibility of the reader to research each and every potential safety hazard. I also suggest reading the entire paper first to familiarize your self with the procedures and note any materials and supplies you may need. ==Glass Preparation== <p>Cleaning the glass properly is important. If the glass is not cleaned properly the emulsion can lift off the glass in spots or completely during processing. Also, if there are any dust particles, the emulsion tends to have different properties at that area and a circular ring of deformation of the hologram will be seen around that area. Soak the glass in a 3% concentration of hydrochloric acid overnight. This can be bought as muriatic acid from most home improvement centers. You could also use a 25% concentration of household bleach. This procedure also works for recycling glass from previously coated plates, but I found the bleach takes longer. After soaking, using rubber gloves, scrub the plates with a plastic wool scrubby used for cleaning Teflon pans. Steel wool may scratch the glass. After scrubbing rinse the glass thoroughly under running water and place in a tray of running water. Then repeat the rinse process while rubbing again with the plastic wool. After the final rinse, lean the plates against the wall on a paper towel. Before the plates dry completely use a paper towel to dry off one plate at a time and continue to turn the paper towel until the plate is dry. You will hear and feel the difference between a damp plate and a dry one. Repeat for the other side of glass. Do not touch the plate with your skin or oils will be left behind which can also cause the emulsion not to stick to the glass. ==DCG Emulsion Fabrication== <p>DCG emulsion is comprised of an amount of distilled water, dry gelatin and ammonium (or potassium) dichromate. A good starting formula is 100:12:3 for the procedures described here. Take the water and place it in a heat resistant glass or plastic container. Place this on a magnetic heater/stirrer or in a double boiler. Add the gelatin to the water while it is cool and allow it to mix for a couple of minutes. If you are not using a heater/stirrer the stirring should be done by hand. Bring the temperature up slowly to a maximum of 120°F and a minimum of 110°F. Once the solution reaches the 110°F temperature, continue mixing until the gelatin mixture is completely dissolved. With the heater/stirrer allow the solution to be well mixed the entire time but not so fast as to cause excessive bubbles or foam. By hand, mix well for one minute every 5 minutes (this get laborious by hand). Mixing too long is better then under mixing, and I suggest 45 minutes after the minimum temperature is reached for a more aesthetic hologram. But again shorter times may be used as long as the gelatin is dissolved. It will look very clear and not cloudy when dissolved with no suspended particles. '''From this point on, a safelight must be used until the after the water bath in processing.''' A good safelight to use is a standard yellow incandescent bug light. Now add the dichromate. Allow this to mix until it is all dissolved (about 15 minutes) within the same temperature range. When this is completed, filter the mixture through a paper coffee filter into a clean container. A funnel or similar can be used to hold the coffee filter paper. It is best to allow the narrow end of the funnel to touch or be very close to the bottom of the final pouring container such that dripping from the funnel end does not produce bubbles. The container can be a beaker or other similar container that can easily be poured from but at the same time can be put back on the heater/stirrer or back in the double boiler to maintain the previous temperature range. If the emulsion is cooler during coating the final emulsion thickness will be thicker. Take a Q-tip and pop or remove any small bubbles that may be on the emulsion. The emulsion is now ready to coat. The emulsion can be stored at this time in a refrigerator, but should be sealed, labeled, and not allowed to be exposed to light. ==Plate Coating== <p>The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120°F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70°F). Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45 degree angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly, you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. Take the plate and immediately place it on a table and spin it as 78 RPM. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. I prefer the spin method. If you run out of emulsion in the pouring container, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. ==Exposing the Plate== <p>The plate is best after 4 hours old and can be up to a week(s) old. I have found the brightest holograms are between the 4 and 12 hour age. It seems when plates are older they are harder to get broadband replay and/or replay into shorter wavelengths and lose some sensitivity. The simplest recording geometry is a [[Single Beam Reflection]] in which the object is lying down on its back and the plate is laid right on top of the object. Make sure the object and plate do not wobble. Place the emulsion facing the object. As DCG is quite relaxing in the energy requirements I suggest doing test exposures with the times being doubled thus covering the largest range of times in the least amount or test exposures. Once the time range is found with your laser it will be easy to reproduce. An example is 10 seconds, 20 seconds, 40 seconds, 80 seconds, and 160 seconds. After exposure allow the plate to set in complete darkness for 2 to 5 minutes before processing. ==Processing the Plate== <p>All temperatures can be at room temperature (70°F). Take the plate and put it in Kodak Rapid Fixer with hardener. The Fixer should be mixed as per the instructions for the most dilute mixture (paper 1:7). Gently rock the tray until all yellow is gone then an additional 15 seconds. This should take anywhere from ½ minute to 2 minutes. I use a white tray to observe the yellow more easily. Once this is completed, place the plate in running water for 5 minutes (a tray of water can be used if running water is not available). I now turn on a quartz halogen light that shines on the spot where I will lean the hologram to blow it dry. Then take the plate and place it in 35% alcohol for 15 seconds. Then 70% alcohol for 15 seconds, then 91% alcohol for 15 seconds then finally 100% alcohol until diffraction is visible (anywhere from 15 seconds to two minutes or longer). As soon as diffraction (colors) is seen, allow another 15 seconds in that bath. Then take the plate out and lean it against the wall in the overhead light. With practice you will find which angle the diffraction is seen in the light and which way that relates to the visibility of the hologram when blow drying it. As soon as you lean the plate against the wall begin blow drying it with a hair dryer set on its hottest and strongest settings. Blow dry very close to the plate. Start at the center and in a circular motion move to the outside of the plate and repeat often. If the plate is leaning the right way the diffraction and image should start to get really bright. Continue drying until hologram in completely dry. You cannot over dry but you can under dry. This usually takes me 5 minutes minimum. ==Sealing the Hologram== <p>If the hologram is acceptable in quality and brightness to your liking, it must be sealed against moisture. After it is completely dry, use a razor to scrap off ¼" of emulsion from around all four edges. Three edges will be easy if you maintained ¼" when pouring the coating. The bottom wiped edge from coating will probably need the most attention. Now have another cleaned piece of glass ready the same size as the hologram. Mix up some 5 minute 2-part epoxy. I use a Q-Tip with the swab cut off. Now take the Q-Tip and use it to lay down a bead of epoxy around the entire cleaned edge on the emulsion side of the hologram. Take the clear cleaned piece of glass and place it over the hologram. You should see the epoxy sandwiched between the glass plates at the edge where the emulsion was scraped. Look closely and make sure there are not voids where the epoxy did not get sandwiched. Let the plates dry horizontally and check often to make sure the top plate does not slide and move into a different location. After about 15 minutes the hologram can be displayed as liked. b0d2e71ea0e52f30408a19f7ff81e2194b875784 0 281 1712 410 2013-04-21T21:58:40Z Admin 0 wikitext text/x-wiki [[Category:Beginner]] ==What is a hologram?== Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ==How little money/bother do I need to make one?== You can make your first hologram with about 2 hours of set up and about $100. ==What is the cheapest way to make a hologram?== [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ==Are the chemicals dangerous?== While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ==What sort of time commitment is there for making a hologram?'''== You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ==When can I have the lights 'on' during the procedure of making a hologram?== Once the emulsion has become insensitive to to light. For Silver Halide holograms this is after the hologram is bleached. For Dichromated Gelatin holograms this is after the fixing and rinsing steps. ==What are the different kinds of holograms?== [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ==What is the single most important factor when making a hologram?== '''Stability!''' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ==How Does a LASER work?== For a simple introduction to lasers read [[How Do LASERs work?]]. ==Can I use a cheap red laser pointer to make holograms?== Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ==Can I use a Green Laser Pointer to make holograms?== So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ==Where are the Reference and Object beams in a Single Beam Reflection Hologram?== Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ==Some uses for [[Everyday Items]] in holography== Click here for [[Everyday Items]] that can save you money in holography! ==What is a [[Scratch-O-Gram]]?== A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and focusing it from a curved scratch to a point. ==What Books are Available for Holography?== See the [[Books]] section. 265b6a6ac4bbb127b9a8812e995cfe4d9a386796 0 159 1562 166 2013-04-21T22:06:53Z Admin 0 wikitext text/x-wiki [[Category:DCG]] [[Category:Beginner]] ==Here's my two cents:== From Joe Farina: Mix dichromate, gelatin, and water using some kind of double-boiler method, and keep it under 60C. Coat plates using whatever method you prefer. Let them dry under a gentle air flow for 4 hours. Store your plates in the refrigerator (use lock & lock or some other kind of airtight container). Make as many plates as possible to enable lots of tests. Do not desiccate or do anything else to them. (By the way, use Knox gelatin from the grocery store.) Now, do tests at your leisure. Just take your container out of the fridge, let it get up to room temperature, and take a plate out (or you can immediately take it out if you hit the surface of the gelatin hard with warm air from a hairdryer to prevent excess condensation). *Expose Denisyuk style with 100 mW at 532 nm. (I would say 2.5" X 2.5" plates would be good.) *Let them set in the dark for 5 minutes after exposure. *Rinse under cold tap water for a minute until the yellowness goes away. *Soak in room-temperature water for a minute. *Soak in 91% for a minute with agitation (room-temperature). *Soak in 99% for three minutes with agitation (room-temperature). *Then dry with hot air. If there is milkiness, you will need to harden the gelatin more after the dark reaction. You can user fixer or a 100W light bulb 6 inches away (for varying time periods) to do this. I prefer the light bulb method. See how your plates age, and how they perform over time. Change variables to see different results (well, I don't need to tell you this, since you probably know better than I do about trial-and-error work in holography). Just use the same principles you use to get such good silver halide holograms. One last word: don't try to pre-plan things too much. Just use the simplest DCG technique possible. (It is really very simple if you have blue or green light.) Don't make it any more complex than it has to be. End of lecture. With a C315M (532nm) at 100mw start with a 1 to 3 minute exposure and adjust by factors of two to find the right exposure range. E.g., 45 seconds, 90 seconds, 180 seconds. 3abd6ada10b8fa629bfc0341770e1bfcc9bd7be8 0 164 1574 176 2013-04-21T22:07:55Z Admin 0 wikitext text/x-wiki [[Category:People]] Media Artist and innovator, since 1967, in the areas of film and video, avant-garde film, video art, holographic art, and more recently, stereoscopic 3D video, digital graphics - web media and web-based virtual reality. His films have received a number of awards, including a 1988 Los Angeles Film Critics Award, and his media art works are found in a number of international collections and have been exhibited internationally, including a 1997 stereoscopic 3D video showing at the Louvre, a 2002 film-video retrospective at the Electronic Media Arts Festival in Osnabruck, Germany, and a 2004 exhibition of 3D video, film, video at SeNef, Seoul, Korea. He also has an extensive background as a teacher in film production / film studies, is a past publisher of two periodicals on film and holography, and has invented / developed a number of film, video, holographic and 3D imaging techniques. In 2000-01 he was involved as Head of 2D/3D Graphics for the Mission Corporation (Bellevue, WA) in developments of speech-interactive (avatar-based) graphical interfaces for next-generation (post-PC) environments. He continues to create independent works in interactive 3D web graphics and installations. He has an extensive background as film and holographic arts producer, project lead and designer, critic, historian, writer, teacher and cultural activist, with special skills as cinematographer, videographer, holographic systems and installation designer, producer and director of films and videotapes, screen-writer, stereoscopic 3D videographer and editor, internet site designer, Speech-interactive Avatar UI designer and HTML and VRML programmer-creator. He is also a writer of screenplays, prose, and prose-poetry. 06e14400b6d0591794b01640a42f2af34755bfbf 0 500 1806 1151 2013-04-21T22:55:01Z Admin 0 wikitext text/x-wiki {| align="center" border="1" |- | align="center" rowspan="2" | '''''Material''''' | align="center" rowspan="2" | '''''Thickness (um)''''' | align="center" rowspan="2" | '''''Spectral Sensitivity (uJ/cm²)''''' | align="center" colspan="4" | '''''Sensitivity (uJ/cm²)''''' | align="center" rowspan="2" | '''''Resolving Power (lines/mm)''''' | align="center" rowspan="2" | '''''Grain Size (nm)''''' |- | align="center" | '''''442 nm''''' | align="center" | '''''514 nm''''' | align="center" | '''''633 nm''''' | align="center" | '''''694 nm''''' |- | colspan="9" | '''Slavich''' |- | PFG-01 | align="center" | 7 | align="center" | &lt;700 | | | align="center" | 80 | | align="center" | &gt;3000 | align="center" | 35-40 |- | PFG-03M | align="center" | 7 | align="center" | &lt;700 | | | align="center" | 1500 | | align="center" | &gt;5000 | align="center" | 10-20 |- | VRP-M | align="center" | 7 | align="center" | &lt;550 | | align="center" | 80 | | | align="center" | &gt;3000 | align="center" | 35-40 |- | PFG-03C | align="center" | 9 | align="center" | 400-700 | align="center" | 1000 | align="center" | 2000 | align="center" | 1000 | | align="center" | &gt;5000 | align="center" | 10-20 |- | colspan="9" | '''Colourholographic''' |- | BB-700 | align="center" | 7 | align="center" | &lt;700 | | | align="center" | 50 | align="center" | 150 | align="center" | &gt;2500 | align="center" | 50-60 |- | BB-640 | align="center" | 7 | align="center" | &lt;650 | | | align="center" | 150 | | align="center" | &gt;4000 | align="center" | 20-25 |- | BB-520 | align="center" | 7 | align="center" | &lt;540 | align="center" | 150 | align="center" | 150 | | | align="center" | &gt;4000 | align="center" | 20-25 |- | BB-450 | align="center" | 7 | align="center" | &lt;470 | align="center" | 150 | | | | align="center" | &gt;4000 | align="center" | 20-25 |- | colspan="9" | '''Kodak''' |- | 131PX | align="center" | 9 | align="center" | &lt;650 | align="center" | 2 | | align="center" | .5 | | align="center" | &gt;1250 | align="center" | 70 |- | 131CX | align="center" | 9 | align="center" | &lt;650 | align="center" | 2 | | align="center" | .5 | | align="center" | &gt;1250 | align="center" | 70 |- | 120PX | align="center" | 6 | align="center" | &lt;750 | align="center" | 60 | | align="center" | 40 | align="center" | 40 | align="center" | &gt;1250 | align="center" | 70 |- | 120CX | align="center" | 6 | align="center" | &lt;750 | align="center" | 60 | | align="center" | 40 | align="center" | 40 | align="center" | &gt;1250 | align="center" | 70 |- | colspan="9" | '''FilmoTec-ORWO''' |- | GF40 (gelatin film) | align="center" | 6 | align="center" | UV to blue-green after sensitization | | | | | align="center" | not relevant | |- | HF53 | align="center" | 6 | align="center" | &lt;550 | | align="center" | 1000 @ 535 nm | | | align="center" | &gt;5000 | |- | HF55 | align="center" | 6 | align="center" | &lt;550 | | align="center" | 250 @ 535 nm | | | align="center" | &gt;3000 | |- | HF65 | align="center" | 6 | align="center" | 580 to 660 | | | align="center" | &lt;100 | | align="center" | &gt;3000 | |- | colspan="9" | '''Ultimate''' |- | Ultimate 15 | align="center" | 7 | align="center" | &lt;700 | | align="center" | 150 | align="center" | 150 | align="center" | 150 | align="center" | &gt;5000 | align="center" | 15 |- | Ultimate 08 | align="center" | 7 | align="center" | &lt;650 | align="center" | 120 | align="center" | 200 | align="center" | 200 | | align="center" | &gt;7000 | align="center" | 8 |- | colspan="9" | '''Fuji''' |- | HL-30 | | align="center" | 100-200 | | | | | align="center" | 3000 | align="center" | 30-40 |} f647d2ceb2c0b6867979a75a8e854794a05aae82 0 805 1566 2013-04-22T21:53:47Z Admin 0 wikitext text/x-wiki === About Ralcon and the founder, RDR === [[Image:Rdr.gif|right]]At Ralcon we design and fabricate prototype HOEs and will occasionally brass board the optical system that the HOE or HOEs will go into, a Spectrograph, a Holographic deflector and a Holo-memory are good examples. We also design and construct a wide variety of more conventional optical instruments such as Telescopes, Transmitters, Imaging systems, Illumination systems, Projectors and Head Mounted Displays. We are photon plumbers, charged with the task of routing as many precious photons as possible from their sources to their designated destinations. We also redesign and fix photon leaks and faulty light valves in existing systems. We deal with hot, cold and mixed photons in trickles or torrents. We are familiar with many kinds of photon generators, coherent, incoherent, partially coherent, fast and slow. Sometimes we can fix your photon generator, or at least tune it up or at least add some novel new accessory to it. Our main skill remains to be the redistribution of your photons into discreet patterns and directions. (All serious work is now done at Wasatch Photonics in Logan) Historically we started business with "jar holograms" and the invention of the Dichromate pendant in 1974. I produced what was probably the first very bright white light reflection hologram of a clock works, From which I launched Ralcon, (then known as the Electric Umbrella). 400 so-so pendant and plate designs followed until 1985 when I "gave" that business to others, currently operating as Krystal Holographics. Our HOE work actually began in 1972 but became profitable in 1979 with the development of an IBM designed bar code reader, for which we made the prototype scanners. We still make new holographic scanner/deflectors from time to time as requested and sell the technology to manufacture them. To date about 20 employees have learned more about holography through these ventures directly and possibly a hundred more through employment at spinoff companies that have sprouted from our original efforts. We still allow independent safe and competent holographers to work in this lab from time to time to complete their pet projects. We are a small company and plan to stay that way. We still resemble a family owned start up company with about $200,000 in assets and split our time between government contracts, aerospace, university and private small businesses. We actually ceased doing business in June of 2004 at the request the Cache County planning and zoning commission. My consulting hours are flexible and run from about 10 AM to midnight. I like to teach and readily accept paid tutorial jobs all over the country as the opportunities arise. I am also a pilot and often fly for fun around the neighborhood or even from coast to coast. <!-- img src="file:///C:/Docs/Images/rdr/Lab%20copter%20rdr.JPG" alt="Labs and toys" style="width: 663px; height: 443px;" align="right" --> RDR and his homebuilt *Rotorway 162F helicopter shortly after finishing it and before the first accident, looks a little different in 2005 after 4 mishaps and a lot of repairs.&nbsp; Also shown is an arial view of the labs and runways and RDR in front of the main lab holding an astronomy grating.<br> '''''Last modified on 11/24/99''''' [[Category:Rallison]] 46f55c7db62ae0bec9a076283e5305bf64705223 0 809 1598 2013-04-22T22:04:47Z Admin 0 Created page with "[[Category:Rallison]] == COMPILED BY RALCON CORP SEPT. 1990 == Aberration-Free Linear Holographic Scanner and Its Application to a Diode-Laser Printer. H.Iwaoka and T. Shiozawa. …" wikitext text/x-wiki [[Category:Rallison]] == COMPILED BY RALCON CORP SEPT. 1990 == Aberration-Free Linear Holographic Scanner and Its Application to a Diode-Laser Printer. H.Iwaoka and T. Shiozawa. bibl flow chart il diags Appl Opt 25:123-9 Ja 1 '86 Aberration Corrections for a POS Hologram Scanner. H. Ikeda and others. diags App Opt 18:2166-70 Jl 1 '79 Aberration Correction in One-Step Lens Image Plane Holography. B.W. Cohen and R. S. Lakes. bibl il diags Appl Opt 27:3322-3 Ag 15 '88 Aberration of Coefficients of Curved Holographic Optical Elements. P.E. Verboven and P.E. Lagasse. bibl diags. Appl Opt 25:4150-4 N 15'86 Aberrations in Nonparaxial Holography. K. Goto and M. Kitaoka. bibl diags J. Opt Soc Am A 5:397-402 Mr. '88 Aberrations of Holographic Toroidal Grating Systems. M.P. Chrisp. bibl diags Appl Opt 22:1508-18 My 15'83 Absolute S- and P-Plane Polarization Efficiencies for High Frequency Holographic Gratings in the VUV. A.J. Caruso and others. bibl il diags App Opt 20: 1764-76 My 15 '81 Absorption and Phase In-Line Holograms; a Comparison. P. Dunn and J. M. Walls bibl il App Opt 18:2171-4 Jl 1'79 Achromatic Combinations of Hologram Optical Elements. S.J. Bennett. bibl App Optics 15:542-5F '76 Achromatic Holographic Stereogram of Landsat Multispectral Scanner Data. S.A. Benton and others. il diags Opt Eng 24:338-40 Mr/Ap '85 Achromatic Triplet using Holographic Optical Elements. W. C. Sweatt. bibl App Opt 16: 1390-1 My '77 Advance in the Processing of Holograms. N.J. Phillips and D. Porter. bibl il Sci Instr 9:631-4 Ag '76 Advances in Bleaching Methods for Photographically Recorded Holograms. A. Graube. bibl App Optics 13:2942-6 D '74: Advances in Holographic Diffraction Gratings Point to Aberration-Free spectrometry. J.M.Lerner and others bibl diags Laser Focus 24:90+ Mr '88 Aliasing Error in Digital Holography. J.P. Allebach and others. bibl il App Opt 15:2183-8 S '76 All Single-Mode Fibre Optic Holographic System With Active Friunge Stabilization. M. Corke and others. il diag J.Phys E 18:185-6 Mr '85 Amateur Scientist: How to Make Holograms and Experiment With Them or With Ready-Made Holograms. C. L. Stong il diags Sci Am 216:122-8 F '67 Anaylsis of a Computer-Generated Binary-Phase Hologram. P.L. Ransom and R.F. Henton. bibl il diag App Optics 13:2765-7 D '74 Analysis of a 4-Port Bragg Device. P.D. Bloch and L. Solymer. bibl diags Inst E.E. Proc 127H:133-7 Je '80 Analysis of a Low-Aberration Holographic Scanner. T. Shiozawa and H.Iwaoka. bibl diags Appl Opt 27: 1992-7 My 15 '88 Analysis of an Active Stabilization System for a Holographic Setup. J. Frejlich and others. bibl il diags Apl Opt 27: 1967-76 My 15 '88 Analysis of Holographic Thin Film Grating Coupler. K. Ogawa and W.S.C. Chang. diag App Optics 12:2167-71 S '73 Analysis of Multiple Hologram Optical Elements with Low Dispersion and Low Aberrations. J.N. Latta. bibliog diags App Optics 11:1686-96 Ag '72 Analysis of Propagation at the Second-Order Bragg Angle of a Thick Holographic Grating. R. Alferness: bibl diags Opt Soc Am J. 66:353-62 Ap '76 Analysis of Volume Holographic Cylindrical Lenses. R.R.A.Syms and L. Solymar. bibl diags Opt Soc Am J. 72:179-86 F. '82 Analysis of Wave-Front Aberrations Caused by Deformation of Hologram Media. M. Matsumura. bibliog diags Opt Soc Am J. 64: 677-81 My '74 Analytic Design of Optimum Holographic Optical Elements. J.N. Cederquist and J.R. Fienup. bibl diags J Opt Soc Am A 4:699-705 Ap '87 Analytic Optimisation for Holographic Optical Elements. E. Hasman and A.A. Friesem. bibl diag J. Opt Soc Am A 6:62-72 Ja '89 Anecdotes on Dennis Gabor's days at CBS Laboratories. L Beiser. Opt Eng 23:SR8+ Ja/F '84 Angular Selectivity of Lithium Niobate Volume Holograms. T.K.Gaylord and F. K. Tittel. bibliog Diags J. App Phys 44: 4771-3 O '73 Anomalies of All-Dialectric Multilayer Coated Reflection Gratings as a Function of Groove Profile: an Experimental Study. L.B. Mashev and E. G Loewen. il Appl Opt 27:31-2 Ja 1 '88 Antenna-Aperture Distributions from Holographic Type of Radiation-Pattern measurement. P.J. Napler and R.H.T. Bates, bibliog diags Inst E.E.Proc 120:30-4 Ja'73 Application of Computer-Generated Holograms to Testing Optical Elements K.G. Birch and F. J. Green. bibliog 2pls diags App Phys 5:1982-92 N '72 Applications of Holography. bibl il diags Opt Eng 24:723-819 S/O '85 Applications of Laser Light. D. R. Herriott. il map diags Sci Am 219:140-4+ S '68 Approximate Bandwidth and Diffraction Efficiency in Thick Holograms. J.E. Ludman. bibl diags Am J. Physis 50:244-6 Mr.'82 Architecture for Optical Computing Using Holographic Associative Memories. H. Mada. bibl diags Appl Opt 24;2063-6 Jl 15 '85 Augmented Laser Scan Equations for Lenticular or Holographic Elements. LBeiser. bibl diags Appl Opt 22:1264-5 My 1 '83 Automatic design of Holographic Gratings for Seya-Namioka Monochromators A. Takahashi and T. Katayama. bibl diag Opt Soc Am J. 68: 1254-6 S'78 Automatic Shutter for Holography. L.H. Lin and H.L. Beauchamp. diag R. Sci Instr 41:1438-40 O '70 Beam Expander for Making Large Rainbow Holograms. diags Appl Opt 26:1815 My 15 "87 Beam Ratio in Multiple-Exposure Volume Holograms. K. Bazargan and others. bibl diags J Phys D. 21 no10S:S160-3 O 14 '88 Bibliography on Holograms. R.P. Chambers and J.S. Courtney-Pratt SMPTE J. 75:373-435, 759-73+ Ap.Ag '66 Binary Computer-Generated Holograms. W.H. Lee. bibl il diags App Opt 18:3661-9 N 1 '79 Binary Fraunhofer Holograms, Generated by Computer. A.W. Lohmann and D.P. Paris. bibliog il diags AP Optics 6:1739-48 O '67 Binary Holographic LO Beam Multiplexer for IR Imaging Detector Arrays. W.B. Veldkamp and E.J. Van Allen. bibl il diags Appl Opt 22:1497-507 My 15 '83 Binary Phase Digital Reflection Holograms: Fabrication and Potential Applications. N.C. Gallagher, jr and others. bibl il diags App Opt 16:413-17 F. '77 Binary Synthetic Holograms. W.-H. Lee bibliog il diags App Optics 13: 1677-82 Jl "74 Boundary Conditions for a Thick Hologram Grating S.R. Seshadri. IEEE Proc 66:1080-2 S '78 Bragg Diffraction in Hologram Gratings with Multiple Internal Reflections. H. Kogelnik. diag Opt Soc Am J. 57:431-3 Mr '67 Bragg Effect Waveguide Coupler Analysis. W.Y. Wang and T.J. Dilaura. bibl diags App Opt 16: 3230-6 D '77 Broadband Imaging with Holographic Lenses. D. Falklis and G.M. Morris. bibl il diags Opt Eng 28:592-8 Je "89 CAD Holograms Cut the Cost of 3D Plant Modelling. V.Wyman. Engineer 264:44 Mr 19 '87 CO2 Laser Beam Shaping With Computer Generated Holograms. D.W. Sweeney and others. bibl il diag App Opt 16:547-9 Mr '77 Cell-Oriented On-axis Computer-Generated Holograms for use in the Fresnel Diffraction Mode. Y.H. Wu and P.Chavel. bibl il diags Appl Opt 23:228-38 Ja 15'84 Characteristics of Active and Passive 2-D Holographic Scanner Imaging Systems for the Middle Infrared. C.S. Ih and others. bibl diags Appl Opt 19:2041-5 Je 15 '80 Characteristics of Holographic Scanners Utilizing a Concave Auxiliary Reflector. C.S. Ih and others. bibl diags App Opt 20:1656-63 My 1 '81 Characteristics of Relief Phase Holograms Recorded in Photoresists. R.A. Bartolini bibliog il diags App Optics 13:129-39 Ja '74 Characterization of Volume and Phase Holographic Gratings. M Quintanilla and others. bibl il diags Appl Opt 23:214-17 Ja 15 '84; Checking Lenses with Holograms. J. Dunn. il Engineer 260:40 F. 7 '85 Coherence Requirements in Holography. M. Bertolotti and others bibliog il diag Opt Soc Am J 57:1526-9 D'67 Coherent Optical Target Recognition Through a Phase Distorting Medium. H.W. Rose and others. il diag Ap Optics 10:515-18 Mr '71 Coherent Transfer Function of a Hololens/Parabolic Optical Fiber System. E. Guibelaide and M.L. Calvo. bibl diags Opt Eng 26:499-506 Je '87 Compact Optical Data Processor Employing Holographic Reflective Lenses. P.C. Mehta and others. bibl il diags App Opt 16:445-53 F '77 Compact Optical Head Using a Holographic Optical Element for CD Players. Y.Kimura and others. il diags Appl Opt 27:668-71 F. 15 '88 Comparison Between Electrical and Free Space Optical Interconnects for Fine Grain Processor Arrays Based on Interconnect Density Capabilities. M. R. Feldman and others. bibl diags Appl Opt 28:3820-9 S.15 "89 Comparison of Deterministic Phase Coding With Random Phase Coding in Terms of Dynamic Range. H. Akahori. bibliog diag App Optics 12:2336-43 O '73 Comparison of Stereograms; Pinhole, Fly's eye, and Holographic Types. J.T. McCrickerd. bibliog diag Opt Soc Am J 62:64-70 Ja '72 Compensation of Aberrations Due to a Wavelength Shift in Holography. J.M. MOran. il diags App Optics 10:1909-13 Ag '71 Compensation of Wavelength-Shift Aberrations in an off-axis Holographic Zone Plate. E. Wihardjo and others. bibl il diags Opt Eng 25:871-4 Jl '86 Computer-Aided X-ray Holographic Imaging System. T. Sato and others. bibl diags App Opt 20:2468-75 Jl 15'81 Computer Analysis of Holographic Systems by Means of Vector Ray Tracing. H.W. Holloway and R.A. Ferrante. bibl il diags App Opt 20:2081-4 Je 15 '81 Computer-Based Analysis of Hologram Imagery and Aberrations. J.N. Latta. bibliog diags Ap Optics 10:599-618 Mr '71 Computer-Based Analysis of Holography Using Ray Tracing J.N. Latta. bibliog diags App Optics 10:2698-710 D '71 Computer-Drawn Modulated Zone Plates. A. Engel and G. Herziger. bibliog il diags App Optics 12:471-9 Mr '73 Computer-Generated Double-Phase Holograms C. K. Hsueh and A.A. Sawchuk. bibl il diags App Opt 17:3874-83 D 15 '78 Computer-Generated Hologram: Null Lens Test of Aspheric Wavefronts. J.C. Wyant and P.K. O'Neill. bibl il diag App Optics 13:2762-5 D '74 Computer-Generated Hologram Recording Using a Laser Printer. A.J. Lee and D.P. Casasent. bibl il diag Appl Opt 26:136-8 Ja 1 '87 Computer-Generated Holograms: Carrier of Polar Geometry. G. Neugebauer and others. bibl il diags Appl Opt 24:777-84 Mr 15 '85 Computer-Generated Holograms: Defect Resistance by Object Phase Manipulation. F. Wyrowski and others. bibl il diags J. Opt Soc Am A 3:1840-5 N '86 Computer-Generated Holograms: Display Using One-Dimensional Transforms. D. Leseberg. bibl il diags J. Opt Soc Am A 3:1846-51 N '86 Computer Generated Holograms for Geometric Transformations. J. Cederquist and A.M. Tai. bibl il diags Appl Opt 23:3099-104 S 15 '84 Computer Generated Holograms for Testing Asheric Lenses. T. Takahashi and others. bibl il diags App Optics 15:546-9 F '76 Computer-Generated Holograms for Testing Optical Elements A.J. MacGovern and J.C. Wyant il diags Ap Optics 10:619-24 Mr '71 Computer-Generated Holograms in Pattern Recognition: a Review. D. Casasent. bibl il diags OptEng 24:724-30 S/O '85 Computer-Generated Holograms of Three-Dimensional Objects Composed of Line Segments. Ch. Frere and others. bibl il diag J. Opt Soc Am A 3:726-30 My '86 Computer-Generated Holograms: Structure manipulation. D. Just and others. il diags J Opt Soc Am A 2:644-8 My '85 Computer-Generated Holograms with Error Compensation. W. Freude and others. bibl il diags Appl Opt 27:138-46 Ja 1'88 Computer-Generated Holograms with Pulse-Density Modulation. R. Hauck and O. Bryngdahl. bibl il diags J. OptSoc Am A 1:5-10 Ja '84 Computer-Generated Holographic Component with Optimum Light Efficiency. H. Bartelt. bibl diags Appl Opt 23:1499-502 My 15 '84 Computer-Generated Holography and Optical Testing. J.S. Loomis. bibl il diags Opt Eng 19:679-85 S/O '80 Computer-Generated Holography: Hologram Repetition and Phase Manipulations. F. Wyrowski and others. bibl il diags J Opt Soc Am A 4:694-8 Ap '87 Computer-Generated Microwave Kinoforms. N.C. Gallagher and D. W. Sweeney. bibl il diags Opt Eng 28:599-604 Je "89 Computer-Generated Polarization Hologram; Experimental Verification. Y. Mitsuhashi and others. bibl il App Opt 16:1138-40 My '77 Computer Holograms Made Cheaper, Faster. Electro-Tech 84:43-4 Jl '69 Computer Holograms with a Desk-Top Calculator. J.S. Marsh and R.C. Smith bibl il diags Am J. Phys 44:774-7 Ag '76 Computerized Design and Generation of Space-Variant Holographic Filters: Applications of Space-Variant Filters to Optical Computing. P. Ambs and others. Bibl il diags Appl Ppt 27:4761-5 N 15 '88 Computerized Design and Generation of Space-Variant Holographic Filters: System Design Considerations and Applications of Space-Variant Filters to Image Processing. P. Ambs Computer Originated Aspheric Holographic Optical Elements. R.C. Fairchild and J.R. Fienup. bibl il diags Opt Eng 21:133-40 Ja/F '82 Computer Produced Holograms for Scanners Utilizing an Auxiliary Reflector. C.S. Ih and others. bibl il diags App Opt 17:1582-6 My 15 '78 Computer Simulation of Holographic Grating Exposure. R.H.M. Dumas and P.J.R. Laybourn. bibl flow chart il diags IEE Proc Part J 132:331-5 D'8 Conjugate Diffraction Order in a Volume Holographic Off-Axis Lens. R. Ferrante and others. bibl il diags Opt Soc Am J. 71-1385-9 N '91 Conjugate Wavefront Generation and Image Reconstruction by Real-time Holography. Z. Jingjiang and others. bibl il diag Opt Eng 25:677-8 My '86 Considerations on Holographic Memories in the Gigabyte Region. H.Kiemle. bibliog il diags App Optics 13:803-7 Ap '74 Contact Printing Method Utizing Heated Photo-resistant Adhesive Property for Hologram Copying. M. Nakano and N. Nishida. bibl il diags App Opt 18:3073-4 S. 15 '79 Contour Map display using Computer-Generated Holograms. W.H. Lee. bibl il App Optics 14:2447-52 O '75 Coordinate Transformations via Multifacet Holographic Optical Elements. H. Bartelt and S. K. Case. bibl il diags Opt Eng 22:497-500 Jl/Ag '83 Copying Reflection Holograms. C.N. Kurtz. bibliog diags Opt Soc Am J 58:856-7 Je '68 Correction of Unequal Longitudinal and Lateral Magnification in Holography. D.C.Winter. diags App Optics 10:2551-3 N '71 Correlation Properties of Random Phase Diffusers for Multiplex Holography. E.L. Dral and others. bibl diags App Opt 21:1281-90 Ap 1 '82 Coupled Wave Theory for Multiple Exposed Thick Holographic Gratings. S.K.Case. bibl il diags Opt Soc Am J. 65: 724-9 Je'75 Coupled Wave Theory for Thick Hologram Gratings. H. Kogelnik. diags Bell System Tech J. 48:2909-47 bibliog(p 2945-7) N '69 Coupling in Doubly Exposed, Thick Holographic Gratings. A.Alferness and S.K. Case. bibl diag Opt Soc Am J. 65:730-9 Je '75 Crosstalk Noise from Multiple Thick-Phase Holograms. W. J. Burke and P. Sheng. bibl J. App Phys 48:681-5 F'77 Cylindrical Holography and Some Proposed Applications. T. H. Jeong. il diags Opt Soc Am J. 57:1396-8 N. '67 Data Storage, Retrieval, and Replication Using Photoanodically Engraved Holograms. A. L. Dalisa and D.J. Debitetto. bibliog il diags App Optics 11:2007-15 S'72 Dennis Gabor, Holography and the Nobel Prize. E.N. Leith. IEEE Proc 60:652-4 Je '72 Dephasing Measure in the Diffractionby a Hologram Grating. S.R.Seshadri. IEEE Proc 66:1079-80 S '78 Describing Holographic Optical Elements as Lenses. W.C. Sweatt. bibl diags Opt Soc Am J. 67:803-8 Je'77 Design and Synthesis of Random Phase Diffusers. C.N. Kurtz and others. bibliog diags Opt Soc Am J. 63:1080-92 S '73 Design Considerations for Holographic Optical Interconnects. R.K. Kostuk and others. bibl diags Appl Opt 26:3947-53 S 15'87 Design Considerations of 2-D Holographic Scanners. C.S. Ih. bibl diags App Opt 17:738-54 Mr 1 '78 Design Methods for a Holographic Head-up Display Curved Combiner. R.L. Fisher. diags Opt Eng 28:616-21 Je '89 Design of Aberration-Balanced High-Efficiency Focusing Holographic Gratings. R. Vila and others. bibl diag Appl Opt 27:3013-19 Jl 15 '88 Design of a New Medium for Volume Holographic Information Processing. M.S. Cohen. bibl ildiags Appl Opt 25:2288-94 Jl 15 '86 Design of Holographic Concave Gratings for Seya-Namioka Monochromators. H. Noda and others. bibl diag Opt Soc Am J. 64:1043-8 Ag '74 Design of Holographic Optical Elements by Using Recursive Techniques. Y. Amitai and A.A. Friesem. bibl il diags J. Opt Soc Am A 5:702-12 My '88 Design of Photopolymer Holograms for Optical Interconnect Applications. J.C. Kirsch and others. bibl il diags Opt Eng 27:301-8 Ap '88 Design Relationships for Holographic Memories. A.V. Lugt. diags App Optics 12:1675-85 Design Techniques for Forming 488-nm Holographic lenses with Reconstruction at 633 nm. M.R. Latta and R.V. Pole. bibl il diags App Opt 18:2418-21 Jl 15'79 Designing and Constructing Thick Holographic Optical Elements. W.C. Sweatt. bibl flow chart il diags App Opt 17:1220-7 Ap 15 '78 Designing Efficient Aberration-Free Holographic Lenses in the Presence of a Construction-Reconstruction Wavelength Shift.K. Winick. bibl diags Opt Soc Am J 72:143- 8 Ja '82 Determination of Physical Parameters and Processes in Hologram Formantion in Ferroelectrics. S.F. Su and T.K. Gaylord. bibl J App Phys 47:2757-8 Je '76 Deterministic Diffusers for Holography. W.J. Dallas. bibliog il diags App Optics 12:1179-87 Je '73 Detour Phase Error in the Lohmann Hologram. J.Bucklew and N. Gallagher. jr. bibl diag App Opt 18:575-80 F 15 '79 Development Effects and the MTF of High Resolution Photographic Materials for Holography. K. Biedermann and S. Johansson. bibliog diag Opt Soc Am J. 64: 862-70 Je '74 Dichromated Gelatin Holograms and Their Applications B.J. Chang. bibl il diags Opt Eng 19:642-8 S/O '80 Dichromated Gelatin Holograms Derived from Agfa 8E75 HD Plates. J. Oliva and others. bibl Appl Opt 23:196-7 Ja 15 '84 Dichromated Gelatin for the Fabrication of Holographic Optical Elements. B.J. Chang and C. D. Leonard. bibl diags App Opt 18:2407-17 Jl 15 '79 Dichromated Gelatin of Improved Optical Quality. M. Chang. bibliog App Optics 10:2550-1 N '71 Dielectric Photorefractive Crystals as the Storage Medium in Holographic Memory Systems. A.Agranat and Y Yacoby. bibl diags J. Opt Soc Am B 5:1792-9 Ag '88 Diffraction by Thick, Periodically Statified Gratings with Complex Dielectric Constant. F.G.Kasper. bibliog il diags OptSoc Am J 63:37-45 Ja '73 Diffraction Efficiency Improvement of Undeveloped Dichromated Gelatin Gratings. S. Calixto and R.A. Lessard. bibl diag Appl Opt 24:317-18 F 1 '85 Diffraction Efficiency of Evanescent-Wave Holograms. W.H. Lee and W. Streifer. bibl diags Opt Soc Am J. 68:795-805 Je '78 Diffraction Efficiency of Specular Multiplexed Holograms Recorded on Kodak 649F plates. J.J.A. Couture and R.A. Lessard. bibl diags App Opt 18:3652-60 N.1'79 Diffraction-limited Holography. R.J. Bieringer and J.A. Ringlien. bibliog il diags App Optics 10:1632-5 Jl '71 Diffraction Pattern Sampling Using a Computer-Generated Hologram. D. Casasent and others. bibl il diags Appl Opt 25:983-9 Mr 15 '86 Diffraction Pattern Sampling Using a Holographic Optical Element in an Imaging Configurationl. M.J. Simpson. bibl diags Appl Opt 26:1786-91 My 1 '87 Diffractive Optical Elements for use in Infrared Systems. G. J. Swanson and W.B. Veldkamp. diags Opt Eng 28:605-8 Je '89 Digital Holography T.S. Huang. il diags IEEE Proc 59:1335-46 bibliog(p1345-6) S '71 Digital in'line Holographic Techniques for Long Wavelength Imaging K.H.S. Marie and others. bibl il diags Inst E.E. Proc 129H:211-20 Ag '82 Diffraction Theory Description of Bleached Holograms. L.F. Collins. bibliog diags Ap Optics 7:1236-7 Je'68 Diffuse-Object Holograms in Dichromated Gelatin. J. Oliva and others. App Opt 21:2891-3 Ag 15'82 Diode Lasers and Hologratings Make Low Cost Optical Head Assemblies. G.T. Forrest. il diag Laser Focus 23:26+ S'87 Dispersion Effects in Relief Holograms Immersed in Near Index Matched Liquids or Christiansen Revisited. H.J. Gerritsen. bibl Appl Opt 25:2382-5 Jl 15 '86 Dry Photopolymer Film for Recording Holograms. R.H. Wopschall and T.R Pampalone. App Optics 11:2096-7 S '72 Dry Polymer for Holographic Recording. S. Calixto. bibl il Appl Opt 26:3904-10 S 15 '87 Dual-Phase Holograms: Improved Design. J.N. Mait and K-H Brenner. bibl il diags Appl Opt 26:4883-92 N 15 '87 Dye-Induced Stabilization of Bleached Holograms. S.L.Norman. bibliog diag App Optics 11:1234-40 My '72 Dye Removal from Holographic Films. D.B. Coblitz and J.A. Carney. App Optics 13: 1994-5 S '74 Dynamic Optical Interconnects: Volume Holograms as Optical Two-Port Operators. D.Z. Anderson and D.M. Lininger. bibl il diags Appl Opt 26:5031-8 D 1'87 Echelle and Holographic Gratings Compared for Scattering and Spectral Resolution. J. Kielkopf. bibl diags App Opt 20:3327-31 O 1 '81 Effect of Emulsion Thickness on the Diffraction Efficiency of Amplitude Holograms. H. M. Smith. bibliog diag Opt Soc Am J. 62: 802-6 Je '72 Effect of Emulsion Thickness Variations on Wavefront Reconstruction. A.D. Gara and F.T.S. Yu. bibliog diags Ap Optics 10:1324-8 Je '71 Effect of Film Resolution and Size in Holography. A.Kozma and J.S. Zelenka. bibliog diags Opt Soc Am J. 60:34-43 Ja '70 Effect of Medium Nonlinearity in Holography; Modification to the Kozma Model. H.C. Schau. bibl App Opt 21:1712-13 My 15 '82 Effect of Polymer Host on Volume Phase Holographic Recording Properties. A. Bloom and others. bibl Polym Eng &amp; Sci 17:356-8 Je '77 Effect of Reference and Illuminating Sources Size in Holography. W.T. Cathey. bibl diags Opt Soc Am J. 69:273-7 F '79 Effects of the Relative Phase Relationships of Gratings on Diffraction From Thick Holograms. N. Tsukads and others. bibl diags Opt Soc Am J 69:705-11 My '79 Efficiences of Zone Plates and Phase Zone Plates. M.N. Horman. bibliog Ap Optics 6:2011-13 N '67 Efficient and Abberation-Free Wavefront Reconstruction From Holograms Illuminated at Wavelengths Differing from the Forming Wavelength. L.H. Lin and E.T. Doherty. il diags Ap Optics 10:1314-18 Je '71 Efficiency of a Dielectric Grating. C.B. Burckhardt. diag Opt Soc Am J 57:601-3 My '67 Efficiency of a Holographic Wave-Front Converter. H. Nishihara. bibl diags App Opt 21: 1995-2000 Je 1 '82 Efficiency and Image Contrast of Dielectric Holograms. J. Upatnieks and C. Leonard. bibliog diags Opt Soc AM J 60:297-305 Mr '70 Electrically Accessible Lippmann Hologram Memory. T. Yasuhira and others. bibl il App Opt 16:2532-4 S'77 Electroforming for Holographic Reproduction. R. Edwards. Plat Surf Finish 75:30-1 Mr '88 Electron Beam Fabrication of Computer-Generated Holograms. S.M. Arnold. bibl diags Opt Eng 24:803-7 S/O '85 Electron-Beam-Generated Holographic Masks for Optical Vector-Matrix Multiplication. S.M. Arnold and S.K. Case. bibl il diags Opt Eng 23:79-82 Ja/F '84 Electron Donors and Heat Treatment; Their Effect on the Diffraction Efficiency of Dichromated Gelatin Reflection Holograms. M. Mazakova and others. bibl Appl Opt 24:2156-60 Jl 15 '85 Elimination of Rear Reflections in Holographic Plates. O.D.D. Soares. diag AM J Phys 48:409-10 My '80 Elimination of Wavefront Aberration of Optical Elements Used in Phase Difference Amplification. S. Toyooka. bibl il diag App Optics 13:2014-18 S '74 Equivalence of Ruled, Holographic, and Lameliar Gratings in Constant Deviation Mountings. M. Breidne and D. Maystre. bibl diags App Opt 19:1812-21Je 1 '80 Equivalent-Lens Theory of Holographic Imaging. W. Lukosz. diags Opt Soc Am J 58:1084-91 Ag '68 Erasable Ablative Holographic Recording. W.T. Maloney and J.B. Thaxter. diags App Optics 11:2993-4 D '72 Error Rates in Computer-Generated Holographic Memories. R.S. Powers and J.W. Goodman. bibl il diags App Optics 14:1690-701 Jl '75 Evaluation of a Technique for the Design and Manufacture of an Off-Axis Holographic Lens in Dichromated Gelatin. H.D. Tholl and others . j Phys D. 21 no102:299- 101 O 14 '88 Evaluation of Hologram Aberrations by Ray Tracing. I.A. Abramowitz and J.M. Ballantyne. bibliog diags Opt Soc Am J 57:1522-6 D '67 Evaluation of Large Aberrations Using a Lateral-Shear Interferometer Having Variable Shear. M.P. Rimmer and J.C. Wyant. bibl il diags App Optics 14:142-50 Ja '75 Experimental Holographic Read-Write Memory Using 3-D Storage. L. D'Auria and others. bibliog il diags App Optics 13:808-18 Ap '74 Experimental Investigation of Some Anomalies in Photographic Plates. A.A. Friesem and J.L. Walker. il Ap Optics 8:1504-6 Jl '69 Experiments in Digital Holographic Recording K. Hacking. bibl il diags Radio &amp; Electron Eng. 50:367-73 Jl '80 Experiments in Long-Distance Holographic Imagery. J.W. Goodman and others. bibliog il diags Ap Optics 8:1581-6 Ag '69 F-16's Headup Display Developed for Lantirn. il diags Aviation W 114:141+Je 8 '81 Fabrication of Thin Periodic Structures in Photoresist: a Model. S. 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Fusek and others. bibl il diags Opt Eng 24:731-4 S/O '85 Holographic Optical Scanning Elements; Analytical Method for Determining the Phase Function. H.P. Herzig and R.Dandliker. bibl diags J Opt Soc Am A 4:1063-70 Je '87 Holographic Optical Scanning Elements with Minimum Aberrations. H.P. Herzig and R. Dandiliker. bibl il diags Appl Opt 27:4739-46 N 15 '88 Holographic Optical Schlieren System (HOSS) R. L. Kurtz and L.M. Perry. bibl il diags Opt Eng 18:243-8 My '79 Holographic Optics for a Matched-Filter Optical Processor. J.R. Fienup and C.D. Leonard. bibl il diags App Opt 18:631-40 Mr 1 '79 Holographic Reciprocity Law Failure. K.M. Johnson and others. bibl diags Appl Opt 23:218-27 Ja 15 '84 Holographic Recording and Reconstruction of Polarized Light With Dyed Plastic. S. Calixto and R.A. Lessard.bibl il diags Appl Opt 23:4313-18 D 1 '84 Holographic Recording by Dye-Sensitized Photopolymerization of Acrylamide. S. 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Laser Focus World 25:71-2 Jl '89 Iterative Method Applied to Image Reconstruction and to Computer-Generated Holograms. J.R. Fienup. bibl il diags Opt Eng 19:297-305 My '80 Kinoform. A Superefficient Pseudohologram. il Electro-Tech 83:40 Je '69 Large-Memory Real-Time Multichannel Multiplexed Pattern Recognition. D.A. Gregory and H.K. Liu. bibl il diags Appl Opt23:4560-70 D 15 '84 Large-Size Distortion-Free Computer-Generated Holograms in Photoresist. K. Biedermann and O. Holmgren. bibl il App Opt 16:2014-16 Ag '77 Laser Beam Scanners Constructed from Volume Holograms S.K. Case and V. Gerbig. bibl il diags Opt Eng 19:711-15 S/O '80 Laser Beam Scanning Using Computer-Generated Holograms. O. Bryngdahl and W.H. Lee. bibl il diags App Optics 15:183-94 Ja '76 Laser Diode Lensless MSF-HOE Correlator. F. Caimi and others. bibl il diag App Opt 19:2653-4 Ag 15 '80 Laser Machining with a Holographic Lens J. M. Moran. il diags Ap Optics 10:412-15 F '71 Laser Machining with Modulated Zone Plates. 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L. Rosen. diags IEEE Proc 55:1736-7 O '67 Monobath Processing for Holography. P.Hariharan and others. App Optics 12:611- 12 Mr '73 Multicomponent Photopolymer Systems for Volume Phase Holograms and Grating Devices. W.J. Tomlinson and others. bibl diag App Optics 15:534-41 F '76 Multidirectional Holographic Scanner for Point-of-Sale Barcode Symbol Reader. K. Nishi and others. il diags Opt Eng 23:784-7 N/D '84 Multifacet Holographic Optical Elements for Wave Front Transformations. S.K. Case and others. bibl il diags App Opt 20:2670-5 Ag 1 '81 Multifocus Dichromated Gelatin Hololens. Y.-Z Liang and others. bibl il diags Appl Opt 22:3451-6 N 1 '83 Multiple Imaging With an Aberration Optimized Hololens Array. A. Senthil Kumar and R.M. Vasu. bibl il diags Opt Eng 28:903-8 Ag '89 Multiple Multiple-Exposure Hologram. K.M Johnson and others. bibl diags Appl Opt 24:4467-72 D 15 '85 Multiple-Reference-Beam Nonlinear Holography With Applications in Suppression of Intermodulation Background Noise. 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Champagne and N. G. Massey. bibliog il diags Ap Optics 8:1879-85 S '69 Resolutionn Limitations in Holographic Images. B.R. Russell. diags Ap Optics 8:971- 3 My '69 Resolution Limits of Holographic Mapping Filters for Geometric Coordinate Transformations. F. Mengal. bibl il diags Appl Opt 27: 339-44 Ja 15 '88 Resolving Power of a Zone Plate. D.J. Stigliani. Jr. and others. bibliog diag Opt Soc Am J 57:610-13 My '67 Resonator Memories and Optical Novelty Filters. D.Z. Anderson and M.C. Erie. bibl il diags Opt Eng 26:434-44 My '87 Reversible Recording and Erasure of Holograms in Photodarkened AS2S3 Thin Film. S.G. Lee and S.S. Lee. bibl diags Appl Opt 25:4512-14 D 15 '86 Review of Resolution Factors in Holography. O.D.D.Soares. bibl diags Opt Eng 22:SR-107-12 Jl/Ag '83 Sampled Computer-Generated Binry Hologram. S.C. Keeton. il IEEE Proc 56:325-7 Mr.'68 Sampling in Digital Holographic Reconstruction. H.Lee and G. Wade. J Acoust Soc Am 75:1291-3 Ap '84 Sandwich Hologram Interferometry. N. Abramson. bibl il diags App Optics 13:2019- 25; 14:981-4; 15:200-5 S '74, Ap '75, Ja '76 Scanned Beam Holography. J. C. Palais. il diag Ap Optics 9:709-11 Mr '70 Scattering Phenomena in Volume Holograms with Strong Coupling. S.I. Ragnarsson. bibl il diags App Opt 17:116-27 Ja 1 '78 Silter Halide Sensitized Gelatin Holograms: Mechanism of Hologram Formation. P. Hariharan. bibl Appl Opt 25:2040-2 Jl 1 '86 Simple Inverting Interferometer With Holoelements. V. Parthiban and others. bibl il diags Appl Opt 27: 1913-14 My 15 '88 Simple Lens-System Models for Holographic Techniques. F. Mandelkorn. bibliog diags Opt Soc A J 63:1119-24 S '73 Simple Variable-Ratio Beam Splitter for Holography. D. Bertani and others. bibl il diags J Phys E. 16:602-3 Jl '83 Simplification of Lee's Method of Generating Holograms by Computer. C.B. Burckhardt. diag Ap Optics 9:1949 Ag '70 Simplified Color Image-Processing System Using a Dichromated Gelatin Holographic Element. Y.G. Jiang. bibl il diags Appl Opt 21:3138-41 S 1 '82 Simulation of Synthetic Discriminant Function Optical Implementation. J. Riggins and S. Butler. bibl flow chart il Opt Eng 23:721-6 N/D '84 Single-beam Holography. Y.P. Hwu. bibl diag Am J.Phys 50:280 Mr '82 Single Holographic Element Wavelength Demultiplexer. J.L. Horner and J.E. Ludman. bibl diags App Opt 20:1845-7 My 15 '81 Single-Mode Fibre-Optic Holography. J.D.C. Jones and others. bibl diags J Phys E 17:271-3 Ap '84 Single-Sideband Holography. O. Bryngdahl and A. Lohmann. bibliog il diags Opt Soc Am J 58:620-4 My '68 Some Aspects of Scanned Reference Beam Holography. J.C. Palais and I.C. Velia. Il App Optics 11:481-3 F '72 Space and Time Variables in Optics and Holography: Recent Experimental Aspects. J.C. Vienot and others. bibl il diags App Opt 16:454-61 F '77 Space and Wavelength Dependence of a Dispersion-Compensation Matched Filter. G.M. Morris and N. George. bibl diags App Opt 19:3843-50 N 15 '80 Space Division Multiplexed Holograms H.J. Caufield. il diags Ap Optics 10:1455-6 Je '71 Space-Invariant Multiple-Grating Interferometers in Holography. B.J. Chang and E.N. Leith. bibl il diags Opt Soc AmJ 69:689-96 My '79 Spatial Resolution of Relief Holograms in Dichromated Gelatin. D. Meyerhofer. bibliog il Ap Optics 10:416-21 F '71 Speckle Noise Reduction by Random Phase Shifters. M. Matsumura. bibl il diags App Optics 14:660-5 Mr '75 Speckle Reduction in Holography with a Spatially incoherent Source. M. Kato and Others. bibl il diags App Optics 14:1093-9 My '75 Spectral and Imaging Properties of Uniform Diffusers. M. Kowalczyk. bibl diags J Opt Soc Am A 1:192-200 F '84 Stabilization of Holographic Fringes by fm Feedback. H.W. Rose and H.D. Pruett. il diag Ap Optics 7:87-9 Ja '68 Stabilization of Holographic Recording Systems with Intermittent Exposure Control. B.J. Pernick and M. Kesselman. il diags R Sci Instr 43:579-84 Ap '72 Stabilizing Techniques for Holographic Recording. B.J. Pernick. bibliog il diags Instr &amp; Control Systems 45:64-8 Jl '72 Staircase Telescope Arrays for Local BeamCompression in one Dimension. A.W. Lohmann and F. Sauer. bibl il diags Appl Opt 28:3830-4 S. 15 '89 Steady-State Space-Charge Fields in Photorefractive Materials for Volume Holographic Interconnections. H.Lee and W.S. Baek. bibl diag J Appl Phys 66:1908-14 S 1 '89 Storage Density Limitation of a Volume-type Hologram Memory; theory, H. Nomura and T. Okoshi. bibl diags App Optics 15:550-5 F '76 Study on the pH Dependence of Diffraction Efficiency of Phase Holograms in Dye Sensitized Dichromated Gelatin. R. Changkakoti and S.V. Pappu. bibl Apl Opt 25:798-801 Mr 1 '86 Submicron Grating Fabrication on Gas by Holographic Exposure. D. Heflinger and others. bibl il diags Opt Eng 21:537-41 My/Je '82 Synthesis of Digital Holograms by Direct Binary Search. M.A. Seldowitz and others. bibl flow chart il diag Appl Opt 26:2788-98 Jl 15 '87 Systematic Design Method for Holographic Zone Plates with Aberration Corrections. Y. Ono and N. Nishida. bibl il diags Appl Opt 26:1137-41 Mr 15 '87 Technques for Fabricating Bragg Reflectors on Si02-Si3N4-SiO2 Rib Waveguides on Si. H.J. Lee. bibl il diags Appl Opt 27: 1199-202 Mr 15 '88 Temporal Coherence Length and Speckle; A Simultaneous Approach to those Problems in Holography. C. Roychoudhuri and others. bibl il diag App Optics 14:2051-3 S '75: Discussion. 15:1680-1 Jl '76 Testing Aspheric Surfaces with Computer-Generated Holograms: Analysis of Adjustment and Shape Errors. B. Dorband and H.J. Tiziani. bibl diags Appl Opt 24:2604-11 Ag 15 '85 Theory of Certain Diffraction Gratings Produced by the Holographic Method. M.V.R. K. Murty and N.C. Das. diags Opt Soc Am J 61:1001-6 Ag '71 Theory of Diffraction by Holographic Gratings. E. Storck and V. Wolff. diag J. App Phys 46:3509 Ag '75 Thoery of Diffraction of Guided Optical Waves by Thick Holograms. R.P. Kenan. bibl diags J App Phys 46:4545-51 O '75 Theory of Hologram Formation in Photorefractive Media. K. Blotekjaer. bibl J App Phys 48:2495-501 Je '77 Thick Amplitude Holograms; Effect of Nonlinear Recording. C.R. Bendall and others. App Optics 11:2992-3 D '72 Thick Holograms in Photochromic Materials. D.R. Bosomworth and H.J. Gerritsen. bibliog il diags Ap Optics 7:95-8 Ja '68 Three-Color Hologram Zone Plates. W.E. Kock. bibliog il diag IEEE Proc 54:1610-12 N '66 Three-Dimensional Doppler Anemometer Using a Holographic Optical Element. F. Schneider and W. Windeln. bibl diags Appl Opt 27:4481-6 N 1 '88 Transient Holograms in dyed plastic. S. Calixto and R A. Lessard. bibl il Appl Opt 23:211-13 Ja 15 '84 Transmission Diffraction Gratings Composed of one Material with Anomalous Dispersion in the Visible Region. H.J. Gerritsen and others. bibl il Appl Opt 27:2781-5 Jl 1 '88 Two-Dimensional Theory of Volume Holograms With Electric Polarization in the Plane of the Grating. L. Solymar and C.J.R. Sheppard. bibl Opt Soc Am J 69:491-5 Ap '79 Ultraviolet Hologram Recording in Dichromated Gelatin. T.P. Sosnowski and H. Kogelnik. bibliog Ap Optics 9:2186-7 S '70 Use of a Holographic Filter to Modify the Coherence of a light field. D.Courjon and others. bibl il diags Opt Soc Am J 71:469-73 Ap '81 Use of a Holographic Lens for Producing Cylindrical Holographic Sterograms R.L. Fusek and L. Huff. bibl il diags Opt Eng 20:236-40 Mr/Ap '81 Use of Dynamic Theory to Describe Experimental Results from Volume Holography. R. Magnusson and T.K. Gaylord. bibl diags J. App Phys 47:190-9 Ja '76 Use of Holographic Optical Elements in Speckle Metrology. C. Shkher and G. V. Rao. bibl il diags Appl Opt 23:4592-5 D 15 '84 Use of Lens Arrays in Holograms. W.E. Kock. diags IEEE Proc 55:1103-4 Je '67 Use of Photoresist as a Holographic Recording Medium. M.J. Beesley and J.G. Castledine. il diags Ap Optics 9:2720-4D '70 Using Computer Generated Holograms to Test Aspheric Wavefronts. J.C. Wyant and V P. Bennett. bibliog il diags App Optics 11:2833-9 D '72 Using a Conventional Optical Design Program to Design Holographic Optical Elements. C.W. Chen. bibl diags Opt Eng 19:649-53 S/O '80 Versatile Beam Splitter for Holographers. P.K. Glanz and N. Haskell. diags Am J Phys 44:712 Jl '76:Discussion. M.E.Cox. 45:590-1 Je '77 Volume Hologram Formation in Photopolymer Materials. W.S. Colburn and K.A. Haines. bibliog il diags App Optics 10:1636-41 Jl '71 Volume Holograms Constructed from Computer Generated Masks. S.K. Case and W.J. Dallas. bibl il diags App Opt 17:2537-40 Ag 15 '78 Volume Holograms in Photochromic Materials. W.J. Thomlinson. bibl diags App Optics 14:2456-67 O '75 Volume Holographic Recording Characteristics of an Organic Medium. R.A. Bartolini and others. bibl App Optics 15:1261-5 My '76 Wave-Front Inversion Using a Thin Phase Hologram; a Computer Simulation. Q. Cao and J.W. Goodman. bibl flow charg il diags Appl Opt 23:4575-87 D 15 '84 Wavefront Multiplexing by Holography. H. J. Caulfield. il Ap Optics 9:1218-19 My '70 Wavefront-Reconstruction Mechanism in Blazed Holograms D. Kermisch. bibliog diags Opt Soc Am J 60:782-6 Je '70 Wavelength and Angular Selectivity of High Diffraction Efficiency Reflection Holograms in Silver Halide Photographic Emulsion. J.M. Heaton and L. Solymar. bibl diags Appl Opt 24:2931-6 S 15 '85 Wavelength Scaling Holographic Elements. M. Malin and H.E. Morrow. Opt Eng 20:756-8 S/O '81 Wavelength Performance of Holographic Optical Elements. T.Stone and N. George. bibl diags Appl Opt 24:3797-810 N 15 '85 White Light Hologram Technique. E.N.Leith and others il diags App Opt 17:3187-8 O 15 '78 Width-Modulated Complex Pserdorandom Diffuser. Y. Nakayama and M. Kato. diags Opt Soc Am J 70:1382-4 N '80 Zone-Plate Coded Imaging on a Microscopic Scale. N.M. Ceglio. bibl diag J App Phys 48:1563-5 Ap '77 Zone Plate Theory Based on Holography. M. H. Horman and H.H.M. Chau. bibliog il diags Ap Optics 6:317-22 F '67:Discussion. K.I. Clifford and G.S. Waldman. 6:1415:Reply. 1415-18 Ag '67 Zone Plate with Aberration Correction. E.N. Leith and J. Upatnieks. diag Opt Soc Am J 57:699 My '67 Books on Holography Abramson, Nils. The Making &amp; Evaluation of Holograms. LC 81-67905. 1981, 92.00 (ISBN 0-12-042820-2) Acad Pr. Applications of Holography in Mechanics Symposium Staff. Applications of Holography in Mechanics:Symposium, University of Southern California, 1971, Gottenberg, WG, ed LC 78-172086. pap. 23.50 (ISBN 0-317-08117-9, 2016842) Bks Demand. UML. Barilleaux, Rene P., ed, Holography Redefined: Thresholds. LC 84-61634. (Illus) 32p. (Orig). 1984 pap 4.00 (ISNB 0-936210-14-1) Mus Holography. Barret, N.S. Lasers &amp; Holograms. LC 87-52000. (Picture Library), (Illus). 32p. (gr.1- 6) 1985 PLB 10.90 (ISBN 0-531-04946-9) Watts. Basov, N.G. Lasers &amp; Holographic Data Processing. 142 p. 1985 pap 4.95 (ISBN 0-8285-2883-7, Pub. by Mir Bupns USSR.) Imported Pubns. -Lasers &amp; Holographic Data Processing. 142 p. 1984. 31.00x (ISBN 0 317-46643-7 Pub by Collets (UK)). State Mutual Bk. Brcic, V. Applications of Holography &amp; Hologram Interferometry to Photolasticity. 3nd ed. (CISM, International Centre for Mechanical Sciences, Courses &amp; Lectures: Vol. 14) (Illus) 58 p. 1975. pap. 10.20 (ISBN 0-387-81163-X) Springer-Veriag. Business Communications Staff, Holography: New Commercial Opportunities. 149p.1986. 1750.00 ISBN 0-89336-480-0, GB-074). BCC Butters, J.N. Holography &amp; Its Technology. (IEE Monograph: No 8).236 p 1972 36.00 (ISBN 0-901223-10-7, MO008). Inst Elect Eng. Butters, John Neil. Holography &amp; Its Technology. LC 73-179369 (Institution of Electrical Engineers, IIE Monograph Ser.:No. 8). (Illus.) pap. 59.00 (ISBN 0-317-08482- 82017592). Bks Demand UMI. Caulfield, H.J. &amp; Lu, Sun. The Applications of Holography. LC 77-107585. 138p. 1970. 18.50 ISBN 0-471-14080-5, Pub by Wiley). Krieger. Caulfield, H.J. ed. Handbook of Optical Holography. LC 79-51672. 1979. 89.50 (ISBN 0-12-165350-1). Acad Pr. Caulfield, H. John, et al. Holography Works. LC 83-62984. (Illus) 72 p. 1984. pap. 25.00 (ISBN 0-936210-13-3). Mus Holography. Cindrich, ed. Holographic Optics: Design &amp; Applications. 1988. 50.00 (ISBN 0- 89252-918-0, 833). SPIE Collier, R. et al eds. Optical Holography. 1977. student ed. 3995 (ISBN 0-12- 181052-6) Acad Pr. Collier, Robert J., et al. Optical Holography. 1971. 94. 50 (ISBN. 0-12-181050-X). Acad Pr. Colombeau, J.F. Differential Calculus &amp; Holomorphy. (Mathematical Studies: Vol 64) 456 p. 1982. 94.75 (ISBN 0-444-86397-4, North-Holland). Elsevier. David, Falk R, et al. Seeing the Light: Optics in Nature, Photography Color, Vision &amp; Holography. 464 p. 1985. text ed. 51.50 (ISBN 0-471-60385-6). Wiley. Dirtoft, Ingegard. Holography A New Method for Deformation Anlysis of Upper Complete Dentures in Vitro &amp; in Vivo. (Illus, Orig.). 1985. pap text ed 42.00x (ISBN 91-22- 00763-6, Pub by Almqvist &amp; Wiksell). Coronet Bks. Easy Way to Make Reflection Holograpms. 3.95 (ISBN 0-89816-072-3) Embee Pr. Ebbeni, ed. Progress in Holographic Applications. 223p. 1985. 43.00 (ISBN 0- 89252-635-1, 600). SPIE -Progress in Holography. 169p. 1987.43.00 (ISBN 0-89252-847-8, 812). SPIE Engineering Applications of Holography Symposium Staff. Engineering Applications of Holography: Proceedings of the Symposium, Los Angeles, 1972. pap 100.00 (ISBN 0- 317-09018-6, 2016751). Bks Demand UMI. Erf, Robert K., ed Holographic Nondestructive Testing. 1974. 69.50 ( ISBN 0-12- 241350-4) Acad Pr. Francon, M. Halography. 1974. 39.95 (ISBN 0-12-265750-0)Acad Pr. Hariharan, P. Optical Holography: Principles, Techniques &amp; Applications. (Cambridge Studies in Modern Optics: No. 2). (Illus) 331 p. 1984, pap. 24.95 Cambridge U Pr. Heckman, Philip. The Magic of Holography. LC 85-27489. (Illus). 256p. (YA) (gr 7 up). 1986.19.95 (ISBN 0-689-31168-0, Atheneum Childrens Bks.), Macmillan. Hildebrand, B. Percy &amp; Brenden, Byron B. An Introduction to Acoustical Holography. LC 73-23037, 224p. 1974. pap 18.95. (ISBN 0-306-2005-8 Plenum Pr.) Plenum Pub. Industrial Radiography Holography. (Illus). 160 p. member 9.50 (ISBN) 0-318- 17205-4 , Order No. 223); nonmember 13.00 Am Soc Nondestructive. Holography. Date not set.2450.00 (Isbn 0-89336-695-1 GB074R). BCC. Holography: Exploiting the Leading-Edge Developments. 340 p. 1987. 850.00 (ISBN 0-914993-15-1).Tech Insights Holography Markets. 161 p. 1984. 1285.00x (ISBN 0-88694-594-1.). Intl. Res. Dev. Huff, L., ed. Applications of Holography. 373p. 1985. 57.00 ( ISBN 0-89252-558-4 523). SPIE -Holography: Critical Reviews. 168p. 1985. 43.00 (ISBN 0-89252-567-3, 532). SPIE ICALEO Holography &amp; Information Processing Eighty-Three: Proceedings, Vol 41. 1984. 35.00 (ISBN 0-912035-22-6). Laser Inst. ICALEO Materials Processing Eighty-Three Proceedings, Vol. 38, 1984. 50.00 (ISBN 0-912035-19-6). Laser Inst. Jeong, ed Practical Holography, No Il. 157p. 1987. 43.00 (ISBN 0-89252-782-X 747) SPIE. Jeong &amp; Ludman, eds. Practical Holography, No.E. 140p. 1986. 43.00 (ISBN 0- 89252-650-5, 615). SPIE. Jeong, Tung H. Display Holography: Proceedings of the International Symposium 1982, Vol I. LC 83-81517. (Illus) 246p. 1983. 43.00 (ISBN 0-910535-02-7); pap 27.50 (ISBN 0-910535-09-9) Lake Forest. -Display Holography: Proceedings of the International Symposium 1985, Vol II LC 83-81517. (Illus) 492p. 1986. 65.00 (ISBN) 0-910535-05-1 pap 50.00 (ISBN 0-910535-04- 3):Lake Forest. -The Second International Exhibition of Holography. LC 83-80923. (Illus.) 24p. 1985. pap text ed. 12.00 (ISBN 0-910535-03-5). Lake Forest. Jeong, Tung Hon, International Exhibition of Holography. Croydon, Michael, compiled by. LC 82-83046. 26 p. (Orig). 1982. pap. text ed. 7.00 (ISBN 0-910535-00-0). Lake Forest. Juptner, W.P., ed Holography Techniques &amp; Applications, Vol 1026. 1989. 51.00 (ISBN 0-8194-0061-0.) SPIE Kallard, T. Laser Art &amp; Optical Transforms LC 78-70638. (Illus, Orig). 1979 pap. 12.50 (ISBN 0-87739-009-6). Optosonic Pr. Kasper, Joseph E. &amp; Feller, Steven A. The Complete Book of Holograms: How They Work &amp; How to Make Them. LC 87-16209. (Science Editions. Ser.) (Illus.) 216p. 1987 . pap. text ed. 16.95 (ISBN 0-471-62941-3) Wiley. Kobayashi, Shoshichi. Hyperbolic Manifolds &amp; Holomorphic Mappings. LC 70- 131390. (Pure &amp; Applied Mathematics Ser: No 2). pap. 39.30 (ISBN 0-317-08025-3, 2017855). Bks Demand UMI. Kock, Winston E. Lasers &amp; Holography: An Introduction to Coherent Optics. rev ed: (Illus). 128 p. 1981. pap 3.50 (ISBN 0-486-24041-X). Dover. Kostalanetz, Richard. On Holography. (Illus). 1979. 1500.00 (ISBN 0-685-95585-0). RK Edns. Laser Measurements. 145 p. 1985. 30.00 (ISBN 0-912035-13-7). Laser Inst. Lee,ed. Computer-Generated Holography. no II 1988. 45.00 (ISBN 0-89252-919-9, 884) SPIE. Machade, S. ed. Functional Analysis, Holomorphy &amp; Approximation Theory: Proceedings (Lecture Notes in Mathematics Ser.: Vol. 843). 636 p. 1981. pap. 38.80 (ISBN 0-387-10560-3) Springer-Veriag. Menzel, Fingerprint Detection with Lasers. 120 p. 1980. 55.00 (ISBN 0-8247-694-0). Dekker. Okoshi, T. Three-Dimensional Imaginary Techniques. 1976. 64.00 (ISBN 0-12- 525250-1). Acad Pr. Ostrovsky, Y.I., et al. Interferometry by Holography. (Springer Ser. in Optical Sciences: Vo. 20). (Illus) 280 p. 1980. 45.00 (ISBN 0-387-09886-0) Springer-Veriag. Robillard, Jean &amp; Caulfield, H. John, eds. Industrial Applications of Holography. (Illus). 192 p. 1989. 45.00 (ISBN 0-19-505855-0). Oxford U. Pr. Ross, F. &amp; Yerkes, E eds. Holography Marketplace, 1989. LC 88-31798. (Illus). 184 p. (Orig.) 1989 pap. text ed. 35.00 (ISBN 0-89496-047-4). Ross Bks. Saxby, Graham. Practical Holography. 560 p. 1988 text ed. 45.00 (ISBN 0-13- 693797-7) P-H. Schumann, W.&amp; Dubas, M. Holographic Interferometry: From the Scope of Deformation Analysis of Opaque Bodies. (Springer Ser. in Optical Sciences: Vol. 16). (Illus). 1979. 42.00 (ISBN 0-387-09371-0). Springer-Veriag. Schumann, W., et al Holography Deformation Analysis. (Series in Optical Sciences: Vol 46) (Illus). 1977. 53.00 (ISBN 0-387-13531-6) Springer-Veriag. Smith, H.M., ed Holographic Recording Materials. LC 77-24503. (Topics in Applied Physics: Vol 20). Illus). 1977. 53.00 (ISBN 0-387-08293-X). Springer-Veriag. Smith, Howard M. Principles of Holography 2nd ed. LC 75-5631. pap 73.30 (2056155) Bks Demand UMI Stoll, W. Value Distribution of Holomorphic Maps into Compact Complex Manifolds. LC 75-121987. (Lecture Notes in Mathematics: Vo. 135). 1970. pap 15.10 (ISBN 0-387- 04924-X) Springer Veriag. Stroke, George W. Introduction to Coherent Optics &amp; Halography. 2nd ed (Illus) 1969. 64.50 (ISBN 0-12-673956-0). Acad PR. Unterseher, Fred, et al. The Holography Handbook, New ed. (Illus). 408p. (Orig.) 1982. pap 16.95 (ISBN 0-89496-017-2). Ross Bks. Vasilenko, G.I. &amp; Tsibul'kin, L.M. Image Recognition by Holography. Tybulewicz, Albin, tr from Rus. LC 88-23739. (Illus) 342p. 1989 85.00x (ISBN 0-306-11017-2, Consultants). Plenum Pub. Vest, ed Holographic Nondestructive Testing: Critical Review of Technology. 117 p. 1986. 55.00 (ISBN 0-89252-639-4, 604). SPIE Vest, Charles M. Holographic Interferometry, LC 78-14883. (Wiley Series in Pure &amp; Applied Optics). 465p. 1979. text ed. 71.95x (ISBN 0-471-90683-2, Pub. by Wiley- Interscience). Wiley Wang, et al, eds. Holography Applications 591p. 1986. 72.00 (ISBN 0-89252-708-0, 673 )SPIE Wenyon, Michael. Understanding Holography, LC 78-965 (Illus) 176 p. 1984. 14.95 (ISBN) 0-668-06414-5); pap 8.95 (ISBN 0-668-06203-7) Arco. Yaroslavskii, L.P. &amp; Merzlyakov, N.S. Methods of Digital Holography. LC 80-16286 182 p. 1980. 69.50x (ISBN 0-306-10963-8, Consultants.). Plenum Pub. </pre> <br clear="ALL"><p></p><hr><hr> <strong><em> Last modified on 7/21/99 <br> e61dda029343401d42e0ecff616aa8b347f391fd 0 810 1602 2013-04-22T22:08:38Z Admin 0 Created page with "== Blazed binary optics, from pc to plastic == Richard D. Rallison<br> Scott R. Schicker<br> RALCON CORP<br> Stephen E. Bialkowski, Ph.D.<br> Dept of Chem and Biochem<br> Utah …" wikitext text/x-wiki == Blazed binary optics, from pc to plastic == Richard D. Rallison<br> Scott R. Schicker<br> RALCON CORP<br> Stephen E. Bialkowski, Ph.D.<br> Dept of Chem and Biochem<br> Utah State University<br> Logan, Utah 84322<br> == SUMMARY == A zone plate with 250 zones has been computed on a 386 machine and printed on 100 sheets of plain paper in a NEC LC890 printer. It was computed in Postscript language with 8 levels of grey in each zone and measured 75 inches in diameter before photoreduction to millimeter dimensions in a Nikon FA camera using Kodak 5052 TMX film. The reductions were made from 50 to 300 times to test the range of system resolution, fine grain Illford holographic film was substituted to test the camera MTF. Three micron layers of resist were used to get maximum phase shift and embossing masters of epoxy and nickel were made and evaluated. The final elements are embossed or cast in a variety of plastics and epoxies on glass, metal or semiconductor substrates. The final copies are efficient micro lenses and gratings useful for fabricating beam deflectors and a variety of stable optical interconnects. Resolutions are not as high as electron beam or laser scanning techniques but equipment and fabrication costs are low. We wrote a program named ZONE2 that will compute and print round or elliptical geometric zone plates with up to 20 shades of grey between zones. A second program named LINES writes linear gratings of the same sort, both generate postscript files that can be scaled as large as the computer system will handle. In our case the practicle upper limit was a 10 megabyte file that printed 250 zones times 8 shades of grey spread over 100 pages. The number of zones per page was found to be limited by the printer artifacts related to printer resolution and the computing of shades of grey in the postscript language. The number of grey shades is similarly limited to about 11 distinguishable shades in the inner zones and perhaps 6 to 8 shades in the outer zones. Geometric zone plates are free of aberrations only for f #s larger than 10 so the restriction to 250 zones means we are limited to a lens that is 10 mm in diameter with a focal length of 100 mm at a wavelength of 500 nm. If we had added a term and made the calculations for an interferometric zone plate we could have gone to an f# of 4 without aberrations using 250 zones in a diameter of 4 mm and a focal length of 16 mm. For some applications we could ignore the spherical aberrations of the geometric zone plate used at lower f #s and we made some in the f # 4 range for examination. Optics in this range require resolutions better than 250 l/mm at their outer limits. The camera was fitted with an f/2.8 Micro-NIKKOR 50mm lens which could reasonably resolve 4 micron details over a small angular field. The camera had to be loaded with individual frames of ILLFORD holographic film to insure a large enough film MTF, then each piece was hand processed in DEKTOL developer which yielded good grey scale. Shooting was done outside on a sunny day at distances of between 12 and 100 feet. The zone plate was cut and pieced together on an 8 by 7 foot substrate made from 2 inch thick urethane foam laminated to smooth white paneling. For maximum thickness we chose SHIPLEY #1400-37 PhotoResist spun onto 2.5 X 2.5 inch float glass squares for making the surface-relief copies of the Silver Halide masters. We had no previous experience with this material and this is what we found would work. 1) We set up a Gyrex IR oven with the low pre-heat on, the main heater control set to position seven, and the conveyer speed set to slowest. We washed the substrates, rinsed them in D.I. water, and dried them in a class 100 clean hood. When the substrates appeared dry,we ran them through the I.R. oven two or three times to dehydrate them and stored them in a clean hood until ready to coat. 2) The oven is then cooled down and set up for the "Soft Bake" step. The pre-heater is turned off, the heater is set to one,(130 to 140 degrees F) and the conveyer is set to its slowest speed ( 6 minutes). A soft bake for the photoresist is accomplished by running it through the oven only twice in succession. Over-baked resist does not react well to light. 3) We use a multiple discreet speed DC spin-coater with a small suction cup for applying the photoresist. The speed control is set to get approximately 900 revs per minute as measured by a mechanical tachometer. The spin coater box is lined with aluminum foil and set up on a class 100 clean bench. A substrate is centered on a suction cup and 3ml of the resist is applied to the substrate. The assembly is moved so as to spread the resist evenly over the surface to be coated. The suction cup is inserted into the spin-coater and spun for three minutes.This produced a dry 6 micron thick coating as measured by a .001 inch resolution dial indicator, ( 2.5 microns per division). 4) After a substrate is coated, immediately run it through the oven for the soft bake step. It is advisable to establish a routine so that residual solvents are uniformly distributed and sensitivity is then consistent and uniform across the substrate and from plate to plate. 5) To make a contact copy of a silver-halide master, we place the master with the emulsion side up onto the photoresist and weight the master down with a half inch thick slab of suprasil. Next we place a non-reflective mask over the suprasil to prevent edge scattering and reflections. Lastly, we expose the whole works to a standard 175 WATT mercury vapor yard light from which the outer glass globe has been removed to allow the full spectrum of UV to escape. Thirty minutes at a distance of one foot worked quite well for us and the lamp had to be fan cooled at that distance or it would melt the plastic. 6) The development process consists of washing the exposed photoresist off of the substrate with a dilute solution of MicroPosit 351 developer ( more commonly known as sodium hydroxide ). We used a solution of three parts water with one part of the MicroPosit 351 Developer Concentrate. Development is carried out in a small tank by uniformly immersing the plate and gently agitating only two times back and forth and then letting the plate lean against the side of the tank film side down. After developing the exposed resist for four minutes, we then rinsed it in a dilute solution of Kodak stop-bath ( 3 ml per 500 ml total volume ) and then De Ionized water for ten minutes. We tried using photo-flow in the rinse water but it left a residue. Dry the finished gratings in a clean hood under a gentle flow of air. DO NOT blow it dry with high pressure air, the grating is easily blown apart at this stage. 7) When we tried hard-baking the gratings in the Gyrex oven we succeeded in melting the resist. We now skip the hard-bake step as it does not seem to be necessary for electroplating or replicating with epoxy. We exported some resist masters to Dazzle Enterprizes for electro plating but we are preparing to do our own plating in the future. Electro plating is necessary to replicate with full depth onto substrates using UV epoxies or thin plastic films. We received 8 shims from two different resist masters made at 28 microns from Dazzle. The shims were made in 4 different thicknesses, 2, 4, 6, and 8 mils thick and were not as flat as we had hoped. Casting against them was carried out with UV epoxies and a nip roller with good results when using the 4 mil shims. Copies were also easily embossed into various plastics using a solvent and a Foster replicator. The Foster replicator is a hand cranked ringer, commonly used to ring out wet articles of clothing. '''''Last modified on 6/3/99<br>''''' [[Category:Rallison]] 9361d6065b3cca7946fe76e43324fa83709fb7b1 0 811 1608 2013-04-22T22:11:43Z Admin 0 Created page with "== Changelog for Ralcon Development Lab web page == I have stopped formally listing updates but there have been a few minor content changes as of&nbsp; Oct 2005, they include up…" wikitext text/x-wiki == Changelog for Ralcon Development Lab web page == I have stopped formally listing updates but there have been a few minor content changes as of&nbsp; Oct 2005, they include updating publications, patents and referrals to Wasatch Photonics plus a new picture of my lab and helicpter RDR<br> Prior changes listed below<br> ==== Changes since 4/8/1999. Most recent are at the top. ==== ---- ==== 1/8/02 ==== *Added a &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/files/Zone-SPIE2001.pdf"&gt;"Hoe Enhanced 355 nm Multichannel Direct Detection Lidar"&lt;/a&gt; paper. ---- ==== 4/4/01 ==== *Added a &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/files/DWDM-Dickson_grating_white_paper.pdf"&gt;"Dickson Grating White Paper"&lt;/a&gt; paper. ---- ==== 1/14/01 ==== *Put up the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/dichrohist.html"&gt;"History of Dichromates"&lt;/a&gt; page. *Rearranged home page. *Updated contact information. ---- ==== 9/13/00 ==== *Updated the "What's New" page. *Added another publication to the "Publications" page. *Added a few links to the "links" page. *Updated the "Experience" page. ---- ==== 5/12/00 ==== Tons of changes this time, although most of them weren't even large enough to warrent updating the "last modified" information. *Almost every page was updated to remove tags having to do with page color. *About half of the pages were updated to correct spelling errors. *The &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/circtpnt.html"&gt;Circle to point converters&lt;/a&gt; page was heavily modified, including a link to a new paper describing &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/circ_and_rot.html"&gt;Circle-to-point conversion and Optical rotary joints&lt;/a&gt;. *Behind the scenes, the site has been moved into a CVS archive. Hopefully this will help with keeping the page up to date. *A large list of &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/dcg-refs.html"&gt;DCG references&lt;/a&gt; was added. *Updates to the "holotools" page to reflect the new location of wxPython. ---- ==== 2/18/00 ==== *Updated the What's New page. *&lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/holotools.html"&gt;Holotools&lt;/a&gt; page now includes TIR2 written in Python for a cozy and simple GUI. ---- ==== 11/24/99 ==== *Added a &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/links.html"&gt;links&lt;/a&gt; page. *Updated the What's New page. *Added two publications to the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/publications.html"&gt;list&lt;/a&gt;. *Notified the world that Ralcon now has indoor plumbing *grin* *Fixed the "next", "contents", and "previous" images on the tutorial page (oops) ---- ==== 7/23/99 ==== *Added a page by Robert Rallison on &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/circtpnt.html"&gt;Circle to point converters&lt;/a&gt;. *Updated sitemap and home page to point to new page. ---- ==== 7/21/99 ==== It's been a long time since I made any changes, so I thought I'd make some big ones. *Major changes to the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/tutorial/index.html"&gt;tutorial&lt;/a&gt; page. All of the entries have been reordered, some of the images have been altered to make them more easily printed, and a "slide show" version of the tutorial is up. *A &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/hoebib.html"&gt;bibliography&lt;/a&gt; has been added. Right now it's just a set of &lt;pre&gt; tags around the very long list. *An updated &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/whatnew.html"&gt;What's New&lt;/a&gt; page is up. *Updated the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/sitemap.html"&gt;sitemap&lt;/a&gt; and home page to reflect changes. Also fixed a spelling error on the home page. No wonder no one has replied to our Employment "Opportunities" section. ---- ==== 6/18/99 ==== *Started a &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/tutorial/index.html"&gt;tutorial&lt;/a&gt; page. Right now most of the material is up, but it is out of order. It's fairly heavy on the images, but they're not big. ---- ==== 6/14/99 ==== *Added a new &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/publications.html"&gt;publication&lt;/a&gt; (the last one). *Removed the publications list from the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/resumes.html"&gt;about us&lt;/a&gt; page but left a link to the separate publications list. ---- ==== 6/8/99 ==== *&lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/main.html"&gt;contact/facilities&lt;/a&gt; page: **Minor cleanup. **Added more people to the contact information list. **Moved the facilities map to the same page. It didn't make much sense to have it on a separate page. *Removed outdated information from the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/whatnew.html"&gt;what's new&lt;/a&gt; page. *Minor changes to the main page (added a reference to "Employment Opportunities", which has always been in the What's New page, but never referenced. ---- ==== 6/3/99 ==== *Finished (mostly) the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/dcgprocess/index.html"&gt;"DCG and other phase materials"&lt;/a&gt; pages. ---- ==== 6/1/99 ==== *Fixed the broken image in &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/hybrid96.html"&gt;hybrid96&lt;/a&gt; and did some minor cleanup to the ALT tags. *Fixed the author information at the top of the page. *Alphabetized the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/sitemap.html"&gt;sitemap&lt;/a&gt; in a more reasonable manner. ---- ==== 5/24/99 ==== *Added a &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/sitemap.html"&gt;"Complete site map"&lt;/a&gt;. *Fixed lots of little bugs in various pages. ---- ==== 5/23/99 ==== *Updated the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/index.html"&gt;main index&lt;/a&gt; to point to the new pages. *Removed link to &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/old/about.html"&gt;"About This Web Page"&lt;/a&gt; page. It just didn't fit. ---- ==== 5/23/99 ==== *Added &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/hybrid96.html"&gt; "Wavelength compensation at 1.064µ using hybrid optics"&lt;/a&gt; page. ---- ==== 5/21/99 ==== *Started this changelog, including some earlier changes. ---- ==== 5/18/99 ==== *Spell checked everything (oops, should have done that a long time ago) ---- ==== 4/22/99 ==== *Fixed the area codes for the contact information (ooops). [Thanks Andres F. Zuluaga] ---- ==== 4/8/99 ==== *Updated the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/whatnew.html"&gt;"What's new"&lt;/a&gt; page for March through June 1999 <br> <br> ---- ---- [[Category:Rallison]] bdf3a936b9820e0c1fe536a7d866b3fa7af1f303 0 813 1612 2013-04-22T22:32:18Z Admin 0 wikitext text/x-wiki [[Category:Rallison]] === A Simple How To === See the paper on ''Circle-to-point conversion and Optical rotary joints'' for more information. {| border="1" cellpadding="10" |- ! colspan="4" | Procedure |- ! Film Specs ! Exposure ! Processing ! Cap &amp; Grind |- valign="top" | Mixture: 10-30-350<br> Spin Speed: 88 rpm<br> Relative Humidity: 75% +<br> Incubation: 3 hrs<br> Temp: 96 deg F + | Wavelength: 488 nm<br> Copy Angle: -2 deg off normal<br> Exposure time: 55 sec for each ring<br> Energy in mj: 30<br> Room Humidity: 58%<br> Room Temp: 67 deg F<br> | Development: 45 sec.<br> Hot Alcohol Baths: 10 sec in each<br> Drying: Slow pull<br> Soaking: none required<br> | Glass: 7059 1/2 mm AR visible<br> Glue: NOA 61<br> Grinding notes: ground to 2" dia |} === Circle to Point Converter Setup and Alignment Procedure === ==== Preliminary Inspection ==== *Verify that all of the stepper motors and controllers are connected properly and that the appropriate relays are connected to their respective devises. *Verify that when using toggling of relays in the script, that no toggles in the script are missed. A toggle is used to close the relay, but another toggle is required to open it again. ==== Alignment ==== To align the mask, you must choose a reference point and align it to that reference. The reference is the stage that the mask is clamped against. The two stages that make up the X and Y axes must be orthogonal. If the laser is focused on the mask and a detector is placed under the mask, a measurement of the power from the laser can be obtained. By moving the Y stage in small increments, you can cut the laser power with the mask. Continue to move the Y stage until the detector is in the 50% power range. Any fluctuation in the power can the be monitored as you move the X stage back and forth. When the mask is aligned, minimal power fluctuation should be seen along the entire length of the mask. This is observed by simply moving the mask with the X stage control and watching the power monitor. The mask must be in it's resting position, therefor the film holder must be out of the way so as not to scratch the bottom of the mask. An alternate method of aligning the mask is to use the laser "knife test". This involves a similar method of focusing the laser to one of the X edges of the mask. The preliminary adjustment is to make the laser orthogonal to the surface of the glass. This is easily done with a mirror placed on the surface of the mask for reflection. When the beam is reflected directly back into the laser, normal incidence with the mask has been achieved. Once the laser's focal point is close to the surface of the mask, which is at the bottom of the glass, the Y axis can be moved to count the number of micron steps are required to block out the laser. By adjusting the laser in the Z direction, you can then continue this process until you are at the focal point of the laser, which is at the point where the laser can be shut out and allowed to transmit with the smallest number of steps by the Y stage. When at the focal point, the laser should be able to be completely shuttered with approximately 30 microns of movement of the Y stage. The stage controllers display the magnitude of the movement in an obvious fashion. Also, the laser should always be oriented in a manner that allows the smallest portion of the beam to be orthogonal with the edge that is being aligned. By simply moving the laser to another edge, orthogonality with the stages can also be measured. This same method is used in making the stages orthogonal in the preliminary portion of this entire setup. ==== Parallelism ==== The stage top, the mask, film holder, and master hologram must be parallel. In order to achieve this, you must use a spatial filter, a collimating mirror, and several other mirrors. A mirror should be placed on each surface that needs to be parallelized. The light must be collimated with a collimating mirror in line after the spatial filter. The mirror on the surface of the reference plane is the first used. By directing the beam down to this reference mirror and adjusting the deflecting mirror, the beam can achieve normal incidence with the reference surface. By placing a white board next to the spatial filter, you can then adjust the same deflecting mirror such that the reflected beam is off axis. This gives you a reference point for all of the other surfaces. Now, with a large collimated beam, you can see the reflected points of all of the surfaces, and simply shim them until all beams lie in the same spot on the white board. This verifies the parallelism of the different surfaces. ==== Master alignment ==== Whereas the master is in place over the mask, and must be swung out of position between each piece of film that is being exposed, it is difficult to make it exactly parallel with the masks Y edge. A square can be used to get this as close as possible as far as alignment is concerned. As far a parallelism with the surface of the mask and film, the section on parallelism explains the process to achieve this. ==== Making the Mask Lie Flat Against the Film ==== A feeler gauge should be used to test the width of the mask and film separation on all sides of the film. The mask should be moved to all extremes and the test should be repeated until all places on the mask have similar tolerance. The mask must make contact with the film or shadow will occur. The film holder has a rotational adjustment to move the film in the Z direction. After the surface of the film and the mask are parallel, this adjustment will allow the mask to lie flat against the film in all positions of the exposure. ==== DCG (DiChromated Gelatin) Film ==== With DCG film, an exposure energy of approximately 20-25 mJ should be used. Older film may require more energy to be exposed properly. An index matching material such as Decahydranaptholine should also be used. This not only acts as an index match, but it also holds the film in place by creating a vacuum effect between the film holder and the film. The exposure is followed with a development time of the following: *Developer: 45 sec. *Rinse #1: dip *Rinse #2: dip *Rinse #3: dip *Alcohol #1: 10 sec. *Alcohol #2: 10 sec. *Alcohol #3: 10 sec. ==== Optical Setup for Exposure ==== In order to expose the rings on the mask, the beam needs to be larger than the largest ring and centered on the ring. The power of the beam should be uniformly distributed also. First the beam should be at normal incidence with the mask. This is accomplished by adjusting the reflected beam to lie directly on the beam of origin. Once this is achieved, the 2.5 degree adjustment in the angle of incidence is easily obtained. A mirror with an angular measure on it's adjustment is used. The mirror is then adjusted such that the beam has a negative 2.5 degree incidence with the mask. At this point the mirror may need to be adjusted toward the beam that is coming from the collimating mirror so that the spot is centered on the rings. Any portion of the beam that is larger than necessary should be masked. The optical path from the laser is as follows: the beam from the laser is sent though a spatial filter and into a collimating mirror. The beam is then directed down to the mask with the mirror that has the angular adjustment measure. Between the collimating mirror and the mirror that directs the beam down to the mask should be the extra mask that makes the spot the correct shape and size for the exposure. ==== Removal of Mask ==== The mask holder should have the mask attached to it in a secure manner and aligned with the rest of the system as stated in the alignment section of the instructions. Now, between exposures, the mask holder with the mask can be removed and replaced in a precise way. Whereas the mask holder is fastened to the base with a single spring bolt, it can be easily removed. The spring bolt holds the balls on the mask holder into the sockets in the base. After removing the mask holder, the film can be placed on the film holder and the mask holder is then replaced. After tightening the screw slightly, enough to hold the balls securely in the sockets, the mask holder should be cycled up and down to ensure that it is in place. A realignment is not necessary if the mask holder is removed and replaced in this fashion. The mask holder should be handled with much care because if the mask is moved even slightly within the holder, a realignment would be necessary. To cycle the mask up and down, simply pull the pin into the solenoid manually and then let the mask lie back down gently. The mask should be cycled several times each time the mask holder is removed from the base. === Using the Scripting Language === ==== Script Format ==== *The script must be written in ASCII DOS text without comments or any extra spacing. *Line 1: Number 1-5 that represents the current number of stages to control. *Line 2: Unique address, number 0-31, for each stage. Addresses should be separated by a single space only. *Line 3: Number of times to repeat the entire instruction set. Lines 4-200: These are the lines that control the stage movement and the relay actuator. *Each line is either a relay control, or a stage control. For a stage control, the fields represent stage address (previously specified), number of steps, and a delay time or pause (number in milliseconds or "p" for pause). These fields are also separated by a space. *For a relay control, the fields represent relay control ("r"), relay number (0-7), and time in milliseconds for relay to be closed. ==== Sample Script ==== The data will be entered in this manner (without comments), starting on line one. {| |- | 3 | ''This is the number of stages to be controlled.'' |- | 6 9 10 | ''These are the unique addresses of the stages.'' |- | 2 | ''This is the number of times to repeat the entire script that follows.'' |- | 9 100 p | ''Move stage at address 9 100 steps and wait for user input "c" to continue.'' |- | r 2 2000 | ''Control Relay number 2, close for 2 seconds.'' |- | 6 100 1000 | ''Move stage at address 6 100 steps and wait 1 second before continuing.'' |- | r 7 2000 | ''Control Relay number 7, close for 2 seconds.'' |- | 10 31000 2000 | ''Move stage 10 31000 steps and wait 2 seconds before continuing.'' |- | r 0 30000 | ''Control Relay number 0, close for 30 seconds.'' |} ==== Software Limitations ==== *Currently only five stages can be controlled at the same time with the program. *As specified by the IEEE 488, the addresses of the stages must be unique and be within the range of 0-31. *The program will only accommodate 200 lines of code in the script. This infers that only 197 control instructions may be loaded by the program. *The number of repetitions of the execution of the entire script is limited to 32000 times. *A line is limited to 80 characters. *All fields must be separated by only a single space. *Time must be entered in milliseconds. *The character "r" must start the line of any relay controlling command. *Currently only 8 relays can be controlled with the program, numbered from 0 - 7. *When "p" is entered in the delay time field of the stage controlling command, the key "c" must be pressed in order to continue with the script. *Steps are limited to the range from -32000 to 32000. *Most of the stages have a one micron resolution, giving steps of one micron. For other stages with different resolutions, the step size will change. The user must modify the script for any differences in stage resolution. *The relay control portion of this program is only accurate down to approximately ten milliseconds. This constraint is a result of the parallel port communication with the relay actuator. ==== Hot Alcohol Bath (HAB) Specs ==== <center> {| border="1" cellpadding="5" |- ! # ! Temp in F ! Specific Gravity |- valign="top" | HAB1<br> HAB2<br> HAB3 | 135 deg<br> 135 deg<br> 135 deg | .86<br> .76<br> .75 |} </center> ==== Table Setup ==== [[Image:Circtpnt.gif|center]] ==== Stepper Setup ==== [[Image:Pic19.jpg]]<br> <br> ==== Testing ==== [[Image:Testing.gif]] '''''Last modified on 5/12/00''''' 52d54bad3cf61f3ae174fc8a3099af8be3206207 0 812 1610 2013-04-22T22:50:23Z Admin 0 wikitext text/x-wiki Doppler shifts in the optical spectrum may be detected either by heterodyne methods using coherent sources or by direct detection of filtered and dispersed return light. The coherent method requires diffraction limited optical trains and a local oscillator. The direct detection method is far more relaxed , requiring only "photon bucket" collection optics and a series of blocking filters and etalons to separate the frequency shifted light into a radial pattern. The direct detection of a Fabray-Perot pattern can best be done with a PMT or microchannel plate that has been constructed to have many equal area electrically isolated detection rings. Such a detector placed at the image plane can handle large fields of view and is good at preserving precious photons. A less expensive alternative would be a device that could effectively transform the output of the etalons into a string of foci spaced correctly to fit into a line of fibers or onto a linear CCD or photo diode array. This device could be called a circle-to-point converter and simply redirects all the rays that enter each of the circular annuluses into unique off axis focal points. One way to do this is to cut out annular sections of the edges of lenses and piece them together with appropriate offsets in their respective focal positions. An extension of this method would be to cut up plastic Fresnel lenses or diffractive lenses. These devices can also be thought of as fractured zone plates, re-assembled for the purpose of separating and detecting the Doppler shift imparted to a narrow frequency laser pulse by winds or moving objects. The increments in frequency occur in equal area annuluses so the coarse appearance of such an optic is that of a zone plate as well. The main purpose for this optical element is the remote detection of regional wind speeds. The same peculiar optical element constitutes a kind of rotary optical joint, useful in coupling wideband signals from a spinning platform to a stationary platform. In this alternative application the device is best made with each annulus being the same width rather than the same area. That would make it appear to be a coarse axicon rather than a coarse zone plate. Otherwise, they are or can be the very same optical element. Each annulus is simply an off axis focusing DOE or HOE that gets shifted laterally by some arbitrary increment between zones. We would change the way they are masked if shooting them in a step and repeat fashion and nothing else. Figure 1 shows a likely layout of the circle to point pattern and figure 2 is the corresponding rotary joint pattern. The circle to point pattern is used with full illumination over the aperture which has been made to have as many as 24 annular regions in a 25 mm diameter. The rotary joint would be used with individual modulated lasers or fibers addressing each zone with only a pencil beam. The number of channels would be limited by the size of the beams and the allowable crosstalk. The focus is shifted conveniently off the axis of rotation and out of the path of any zero order light in both applications. The method of fabrication and replication can be the same for each device. We made units with 24 zones as computer generated binary patterns recorded directly in photopolymer. They could also have been patterned into photo-resist and dry etched into silica. We opted to add a high frequency carrier to eliminate the possibility of cross talk from higher orders, alternatively a correct blaze could have been used at lower frequencies so that the parts could easily be fabricated by mechanical replication. We also made the same functional units by starting with a holographically constructed master which was subsequently stepped between exposures along with a mask of 7 or 24 rings. The HOE constructed this way can then be copied optically in one step into another volume recording material for higher volume production. [[Image:Difctp.gif|center]] <br> [[Image:Dorjoint.gif|center]]<br> == Acknowledgements == The diffractive design and fabrication of the rotary joints were carried out independently by Mathias Johansen and Sverker Hard at the Chalmers University of Technology in Sweden and the design of the circle to point converter was contributed by Matt McGill and others at Goddard Space Flight Center with fabrication being done at Ralcon development lab. Patents have been filed for or granted to both parties and both are deserving but I can't help being amused by the entirely coincidental invention of the same complex diffractive optical element for two widely differentiated applications. It makes me wonder how often such things occur. More details about each of these optical elements and the applications the were designed for can be found in the references and from the authors. Optical Interconnects is another field where similar devices may be used and could be searched for. It would not be a surprise to find the same device in the literature of that field and possibly also in holographic memories. == References == #Matthew J. McGill, M. Marzouk, V. S. Scott, J. D. Spinhirne &lt;Holographic circle- to-point converter with a particular application for Lidar work&gt; Opt. Eng. Vol 36 pp 2171-2175 Aug 1997. #Mathias Johansson, Sverker Hard &lt;Design, fabrication, and evaluation of a multichannel diffractive optic rotary joint&gt;, App Opt, vol 38, no. 8, pp 1302-1310, 10 Mar 1999. #R. D Rallison &lt;Fractured zone plates for spatial separation of frequencies&gt; SPIE vol 3633, pp 92-102, Diffractive and Holographic Elements, San Jose, CA, Jan 1999 <br> '''Last modified on 5/12/00''' [[Category:Rallison]] 708927cd9e645be48c5081b0cf0ce04c58289e01 0 823 1658 2013-04-23T00:17:18Z Admin 0 Created page with "Much of the energy projected onto a diffuse surface is scattered at high angles as it is either reflected or transmitted. A volume type diffuser also depolarizes light as it is s…" wikitext text/x-wiki Much of the energy projected onto a diffuse surface is scattered at high angles as it is either reflected or transmitted. A volume type diffuser also depolarizes light as it is scattered. The gain of a projection screen is the ratio of energy reflected into a specific angular zone to the energy that would be reflected from a perfect diffuser. Small glass beads on a screen will return projected light to its source, yielding a high gain in an angular zone around the source. Other shapes of refracting and reflecting material can be molded into screens to produce high gains in retroreflecting geometries and a few anamorphic or single plane scattering surfaces that may be made of lenticular optics. The available directions for high gain and the angular shape of the gain zone are limited by refractive optics but become nearly arbitrary for diffractive optics. Dispersion in diffractive optics prevent them from being used over very broad bandwidths but if the application is insensitive to this dispersion then diffuse energy may be directed and concentrated in some very unusual ways using diffractive screens. The simplest form of directional diffuser is made by interfering a plane or diverging wave with a diffuse wave in either a reflection or transmission format. The resulting hologram will reconstruct the diffuse source when illuminated at the original angle and wavelength. If the same hologram is used as a projection screen, the information being projected onto it will only be visible when the diffuse source is visible. All other viewing positions and illumination geometries will see a diminished projection or nothing at all. The position and size of the original diffuse source will determine the viewing zone and the gain of the screen. A small diffuse source recorded a meter away from the holographic plate will form a very high gain screen that is visible only when the viewer is in the angular zone subtended by the small source at 1 meter. The same screen may be made to reflect only a narrow band of wavelengths centered around a particular phosphor or laser line, making it practically invisible for all other directions and colors. This sort of screen can be useful in conserving projected CRT or laser light in a cockpit or simulator. The angles chosen for construction and reconstruction are somewhat arbitrary so that specular reflection from the projector can be avoided in the viewing zone. We have constructed green screens of this variety with gains of 25 and efficiencies greater than 70%. When photons are precious and a small viewing zone or box is acceptable then this is a very good solution. The viewing zone cannot always be constructed with real sized sources at end use distances. The viewing zone can always be specified as a set of angles or a specific pattern and scaled with lenses during construction. Perhaps the most useful and general method of creating a specified viewing zone is to project the pattern to infinity during construction. This is done by placing a correctly scaled diffuse pattern 1 focal length away from a lens placed close to the recording plane. The scaling is most easily done by ray tracing from the film plane through the lens to a plane one focal length away. This method also cancels aberrations introduced by the lens during construction. The lens limits the size of the hologram and thus the size of the screen that can be recorded this way. Practical lenses for this purpose are usually only 6 or 8 inches in diameter although some are available up to about 20 inches. Large screens must then be made some other way. One of the applications we have dealt with recently required that we make a screen several times larger than we were able to expose in one shot. The angular viewing window was large and the surface area of the final screen was also large. We were limited by available laser light and lenses to a screen about 5 inches square. In order to make a larger seamless screen we multiplexed many overlapping exposures of the small screen on a much larger glass plate. One screen consisted of 144 separate exposures. The reason we could do this and maintain a constant angular viewing zone is because we had recorded a diffuse surface from infinity. In use the screen is visible only when the surface is reconstructed at infinity behind the viewer. Since it is at infinity, the angular zone remains constant for any size extended surface. This trick would be incredibly difficult to duplicate with conventional optical elements. Another important property of these screens is their nearly transparent appearance to anyone not in the viewing zone. These screens may be applied to windows in observation and control towers where they remain transparent while reflecting just like an opaque beaded reflecting screen for those in the viewing zone. Simple small LCD projectors can easily be seen in a lighted room due to the high gain and efficiency of the screen and the view of the outside world is only slightly colored and obstructed. Backlit displays or control panels may also be overlaid with this type of screen to project information as needed without obscuring the backlit displays. This property is even more difficult to duplicate in refractive optics. Any refractive or reflective surface that diffuses incident radiation at one angle usually does so at all angles. Diffractive optics on the other hand do very little to incident radiation at the wrong angle or the wrong wavelength. We refer to the second type of screen as an infinite conjugate directional diffuser because of its unique scaling property. Other directional diffusers have an ideal viewing zone that includes a finite distance and cannot be extended in size without enlarging and moving the viewing zone. Either variety may be constructed as a transmission or reflection hologram but all of our work has been with reflecting structures which are also naturally wavelength selective. Transmission screens can be used as diffuse illuminators of objects or selected areas of a plane. Patterns with unique properties in scale, focus and intensity distributions may be produced with these methods. Holographic directional diffusers are a unique class of optical elements that in general cannot be duplicated with conventional optical components. <br> '''''<br> Last modified on 8/2/97''''' [[Category:Rallison]] 27c780e3bf65ca08d82ad754a10023dd9186c2df 0 824 1672 2013-04-23T00:52:18Z Admin 0 wikitext text/x-wiki == Common DOE surfaces == === Sinusoidal, triangle === {| |[[Image:Sine.gif|left]]<br> | *Max D.E. ~ 30% +/-1 order *Power distribution follows Bessel function in the scaler region. *T [[Image:Simeq.gif]]&nbsp;[[Image:Lambda.gif]]&nbsp;for transmission. *T [[Image:Simeq.gif]]&nbsp;[[Image:Lambda.gif]]&nbsp;/ 4 for reflection. *Easily replicated or deep etch can yield higher efficiency. |} === Square, rectangle === {| |[[Image:Square.gif|left]] | *Max D.E. ~ 40% +/-1 order. *Power distributions favors odd orders. *Pi phase shift typical. *Classic binary grating. *T [[Image:Simeq.gif]]&nbsp;[[Image:Lambda.gif]]&nbsp;for transmission. *T [[Image:Simeq.gif]]&nbsp;[[Image:Lambda.gif]]&nbsp;/ 4 for reflection. |} === Blazed, sawtooth === {| |[[Image:Blazed.gif|left]] | *Max D.E ~ 98% *Reflection Case: **[[Image:Lambda.gif]]&nbsp;= 2 d sin a **T = [[Image:Lambda.gif]]&nbsp;/ 2 +/- 10% *Transmission Case: **[[Image:Lambda.gif]]&nbsp;= d sin b **a [[Image:Simeq.gif]]&nbsp;2b **T = [[Image:Lambda.gif]]&nbsp;/ (n-1) +/- 10% **Surface shadows reduce D.E. by&nbsp;[[Image:Equ1.gif]] **Wavelength changes reduce D.E. by&nbsp;[[Image:Equ2.gif]] |} == Holographic Deflectors (hologons) == {| |[[Image:Scan.gif|left]]<br> | *N = [[Image:Theta.gif]]&nbsp;D / ( 1.4 [[Image:Lambda.gif]]) *N = number of resolvable spots *[[Image:Theta.gif]] = full scan angle in radians *D = beam diameter in microns *[[Image:Lambda.gif]]&nbsp;= wavelength *[[Image:Phi.gif]]&nbsp;= wedge angle of glass *Special case of linear scan and near wobble invariance&nbsp;[[Image:Invariance1.gif]] max straight scan angle ~ 36 deg</span> *Dynamic wobble&nbsp;[[Image:Dynwob1.gif]] *Wedge wobble = (n-1) [[Image:Phi.gif]] *Scan angle multiplier = 1.4 @ 90degrees cross scan angle |} '''''Last modified on 9/29/97''''' [[Category:Rallison]] 046212e4a75caff1d446376db7e035205f0c0984 0 825 1680 2013-04-23T01:07:13Z Admin 0 wikitext text/x-wiki == The Why, When, and How of Fringe Locking == === WHY LOCK === In any holographic recording set up there is a finite probability that the relative phases of the two or more interfering waves will be perturbed during the time necessary to complete the exposure. Any perturbation at all can affect the final uniformity, brightness and viewing aperture of the recording. Our success as holographers literally depends on how well we can reduce the probability of an untimely relative phase error. In other words we have to stop everything on the table from resonating, creeping, shrinking, distorting, buckling, flowing, rocking, sinking, expanding, bowing, settling, slipping or waving in the breeze. We have to stop the breeze and all its gradients too. Two ways around the problem are to always make only contact copies in thick glass or to only use a Q switched laser source or both. For virtually all other tasks we must do what we can to eliminate any and all sources of air, component or table movement. A wise holographer does his best to stabilize the environment, block drafts and use rigid robust components and then tests the table with a Michelson interferometer. Let me suggest that you test your table by setting up an interferometer with longest possible arms and display the fringes on a screen with a grid on it or if possible place a pair of photovoltaic cells over a fringe and watch the differential voltage change. Do your best to block all sources of error and let everything settle for an hour then watch for fringe drift over 1 to 5 minutes.You may be surprised to see that your best efforts could not prevent the measurable displacement of a fringe over that much time. If you are working with a steel table, try holding your hand an inch or two away from the surface and watch the fringes drift slowly across the screen as the table heats up. A few experiments like this will convince you that there is often a good reason to go to the trouble to electronically stabilize your set up. === WHEN TO LOCK === Persons involved in production transfer type copying can benefit from stabilized setups to get more consistently good copies. Exposing in polymers and resists often takes so long that you would likely get nothing at all if a locker were not used. In less severe cases the use of a locker for exposures of more than a few seconds will always result in a recording of maximum fringe contrast which usually means highest possible signal to noise ratios and highest efficiency. I found that I could not make 8 by 10 reflection transfers into DCG from transmission masters without a locker on line. Most of my experience is with reflection transfers in dichromated gelatin as shown in fig 1 or with the fabrication of first generation HOE elements in sizes up to 16 inches square and exposures up to 20 minutes,(above which time uncompensatable distortion tends to wipe me out in large formats). Fringe lockers are best at compensating for simple linear thermal growth or contraction of a table. They also do well with common vibration problems but cannot do much for a flimsy drafty arrangement. In other words, probably nothing can compensate for incompetence or ignorance of mechanical and optical principles but when all else fails they can make the difference that counts. The Stabilock II fringe locker is available from Odhner Holographics, PO Box 841, Amherst, New Hampshire (PH;(603) 673-8651 or FAX: (603) 673-8685 (Jeff Odhner: &lt;a href="mailto:jodhner@stabilock.com"&gt; jodhner@stabilock.com&lt;/a&gt;)." Jeff now has an RS-232 option for the Stabilock II Fringe Locker with a LabView driver. It is great for hands-off fringe locking applications. The driver will not only allow total control of zero, gain, and damping from the computer ("manual control via mouse") but will also enable the fringe locker to go into an "auto-lock" setup before every exposure so that the system is always optimized. ==== Figure 1a. Reflection Transfers Using a Locker ==== [[Image:Lock1a.gif|center]] ==== Figure 1b. Transmission Transfers Using a Locker ==== [[Image:Lock1b.gif|center]] <span style="line-height: 1.5em;">Some of the problems a locker will not help much with include distorting plates or components, uneven heating of components by absorbed light, random graded air drafts,large drifts in laser frequency and large amplitude vibrations or transients. If you have arranged geometries so that fringes sensed by the locker were generated very near the film plane then a hologram will be formed in the local area in spite of the severe movements mentioned but the rest of the plate will likely be blank, banded or dim.</span> <span style="line-height: 1.5em;" />The allowable movement to get a good recording varies with the kind of recording being made and is best described in terms of a&nbsp;% of a fringe. At 100% fringe movement we get total cancellation but even 10% is going to be noticeable, so our goal should be 1 or 2% max allowable which translates to .004 microns of path length change in the worst case reflection geometry but may only translate to 1 micron in a narrow angle transmission set up. In general the benefits of a locker will be most noticeable when making reflection holograms which tend to be several times more sensitive to path length changes than transmission holograms. Stabilization over many minutes with tolerances of under a hundredth of a micron seem unlikely and unrealistic but that is what is required and that is about what you can get from a well made and properly employed Fringe Locker. === HOW TO LOCK === &lt;u The first step in fringe locking is to get a good look at the fringes that are to be locked onto. They can be magnified at the film plane at the expense of available energy or simply generated near the film plane for easy viewing and sensing electronically. It is very gratifying to be able to easily see with your eyes what is going on in real time so I always have chosen the fringe generation method rather than direct sensing and sampling. I place a beam splitter behind or to the side of the film holder and orient it so that one of the input beams is reflected to be collinear with the other beam. A small cross scratched into the surface of the splitter helps to align the two beams on a screen placed on a distant separate table. Everything is adjusted to get the biggest brightest fringes possible by inserting filters and lenses or picking different ratio splitters as necessary to get the best contrast and size. The locker will do fine with only a 1 mm fringe but I like to have a few fringes blown up to several inches wide on a cross hatched white screen so I can watch even the tiniest quiver or catch a fluttering mode or a mode hop during the exposure.<br> <br> Another very useful method of generating fringes is to make a small hologram in a holder near the film plane and lock onto the moire fringes that result in placing it back in the set up slightly off its original angle. This method presupposes that the set up is stable enough to make at least a weak hologram without a locker so if it isn't then it can be very frustrating. It is a very general method otherwise and can be used with available diffuse image light rather than the strictly locally available specular light needed for the beamsplitter method. I always opt for the beamsplitter when it is possible to get light where I need it but have resorted to the hologram / moire method when I couldn't and find it only slightly more cumbersome. One pleasant benefit is that it always produces straight fringes over a large area whereas the splitter may only yield the distorted center of a zone plate with a single pair of fringes to lock onto and view.<br> <br> The next step may have preceded the first step but not necessarily so. A transducer capable of introducing an optical path length change has to be introduced into one leg of the set up. The common choice is to reflect off a mirror mounted on a piezo bimorph or a speaker coil. Some drivers such as the STABILOK II move a bimorph far enough to be used in transmission mode by translating a wedge or prism to introduce a relative phase shift or optical path length difference, (OPD). If two prisms are used it is not necessary to include the transducer in the original set up prior to finding or generating fringes, the assembly may be pushed into place after the fact with only minor adjustments to prior alignments .<br> <br> The two methods are illustrated in Fig 2. Before making the choice of mounting wedges on your bimorph consider that it moves over about 6 microns which may represent 30 fringes using a mirror at reasonable angles but will be only 7 or 8 fringes when used with a 45 degree prism of refractive index equal to 1.5. OPD equations are given for each configuration where L = the max bimorph travel and n = the index of refraction of the prism. ==== Fig 2. Mirror and Prism Configurations ==== [[Image:Locker2.gif|center]]<br> === SETTING UP THE STABILOK === The final step is connecting and adjusting the electronic hardware. The electronics of the STABILOK II consist of a simple but subtle differential amplifier with a few tweaks for fine tuning. The amp is required to be both stable and high gain, it must not drift over very long periods of time while responding to slowly drifting inputs and an occasional sharp transient or harmonic oscillation. In order to lock with a 20th of a fringe or better tolerance, the gain has to be as high as it can go without running the whole system into instability. The gain control is turned up until the fringes fuzz out and then it is backed off to where they are first clearly visible and solidly locked. The frequency response or damper control may be left up all the way or if vibration is not likely may be reduced or "rolled off" so that gain can be increased even higher to correct even tinier slow drift corrections. I like to tweak all the controls liberally to see how the set up is going to respond. Each set up has its own peculiar resonances and weaknesses which can all be observed if you have generated an easy viewing port away from the set up with large bright fringes. After I get it all tuned up as best I can I stomp on the floor and tap the table and a few suspect components to find and fix any problems with the locker off and then on. Next I let everything settle for a few minutes to half an hour and then begin rapid fire shooting,relying on the locker to compensate for about a fringe worth of movement in every shot. The locker will allow you to significantly increase your throughput as it cuts settling time dramatically in a production set up. I have used by now 6 different fringe locker designs and I really like the newest unit from MEI, the STABILOK II. It has an illuminated scale to let you know if it will work with available light and to center the bimorph travel. The same scale lets you track the action during exposure and even measure the amplitude and direction of the drift. The dynamic range is the range of usable input energies and is very large on this model.The gain is incredibly high which means it will oscillate but it will also lock on very tightly. The stability is better than the spec of a 20th of a wave when care is taken to generate large clean smooth fringes. The sensors are simple , rugged photodiodes in a balanced differential pair and the bimorph is damped and rigidly mounted. Drift is very low without feedback and essentially zero after a lock is made. Monitoring via a strip chart recorder is made convenient from a BNC output connector. === SUMMARY === Fringe locking is often advisable or even necessary. It is only difficult for the first time or two and is usually quite simple to accomplish, requiring at times a little ingenuity and always some patience to generate fringes. The hardware is fairly rugged and laser grade dielectrics or prisms may be used by simply gluing them over the existing mirror. First timers are advised to experiment with their tables in the manner previously described to discover not only how to use the devices but to determine what is moving and what is not in any set up. Since the task is usually to compensate for table growth a separate laser and optical paths running parallel to the holographic set up with one shared mirror may work for you. And last of all, I think experimenting with lockers is even fun sometimes. [[Additional use for Fringe Locker]] '''''Last modified on 8/13/98''''' [[Category:Rallison]] a7a40214327f94ed4c385888bfeb165d3050a9f6 0 806 1570 2013-04-23T01:07:46Z Admin 0 wikitext text/x-wiki === Correcting steel table thermal drift with a fringe locker and auxiliary laser === A fringe locker is usually used to sense the recording wavelength fringes at the film plane and feedback correction to a moving mirror or moving prism in one leg of the set up. This works best and should always be tried first. Some set ups require the use of scarce blue photons which are not readily absorbed by ordinary silicon detectors. The power available for fringe locking is sometimes frightfully low and a "hard" lock is not possible. One solution is to buy more blue photons, another is to buy more sensitive photo diodes or photo transistors and install them in the head, another is to concentrate the light at the detectors with a lens, and still another would be to add more gain at the input stage. Even when there is enough light to make the locker work, there may be a diffuser or a diffuse object somewhere in the set up and therefore a diffuse wave that will not make a clean high contrast set of fringes to lock onto. For this case a few extra optics will often provide a second specular beam to use to form clean fringes. If none of these options are possible or attractive then there is still one more option that may work that requires several more optical mounts and optics but no more precious blue photons. For this option you need a simple 1 mw red HeNe or stabilized red or near IR diode laser as a secondary laser and enough optics to zig and zag down the same approximate paths taken by the primary blue laser light. The secondary light is required to share only one common surface with the primary light and it can usually remain on all the time and may even be considered part of the safe light fixturing. The object of using the locker in the first place is to compensate for long term drift in the table.This is not always the case but it is the most common task required and the most difficult problem related to long exposures. The components themselves may also warp slowly during an exposure but nothing much can be done about that. When the components are tall or raised above the tabletop a significant distance then table bowing may be a more serious problem than simple linear changes. In this case it is best to mount the beam combiner high up on the film plane, perhaps 2/3to 3/4 of the distance from the table top to the top of the film holder or film or plate. This positioning produces a good compromise between bow and linear compensation and will work when using primary laser light or secondary laser light. The only surface that has to be common to both primary and secondary waves is the moving mirror on the bimorph but it is also a good idea to mount the secondary wave combiner on the film plane whenever possible. This will make two surfaces essentially common and if the splitter can also be common, then so much the better. [[Image:Genlock.gif|center]]The above drawing shows a generalized locking scheme using a second red laser. The paths taken by the red light are roughly parallel to and of the same length as those taken by the blue light.Feedback from the red fringes formed by the combiner, BS3, will move the bimorph and change the path lengths for both colors simultaneously. Gross table drift will be adequately canceled but local or component drift and warpage will be unchanged. This system is very general and it would be fair to change the set up to record rainbow holograms and even use some reflection recording geometries in the blue zone shown without changing the red zone arrangement at all. Of course the acid test is to shoot a few shots and check for movement fringes and repeatability. The general reflection hologram is something of a special case. Fringe sensitivity to path length changes is at a maximum, often 10 times more sensitive than a transmission set up so some special precautions may have to be taken to get adequate stability. One precaution would be to follow the primary path more closely than shown, perhaps even mounting the red mirrors on the same posts with the blue mirrors whenever possible. Another precaution would be to calculate the correct angle of incidence of the red light on the bimorph mirror. The red angle will be different than the blue angle but related by the difference in wavelengths. The fringes in red are larger than the fringes in blue and the correct motion of the bimorph to compensate for a wave of error in the blue is smaller than for a wave of error in the red. The drawing shows the red beam at a shallow angle with respect to the normal of the bimorph mirror and the blue beam at a larger angle. In general this will be correct because the largest wavefront displacement occurs at 0 degrees and the smallest at grazing incidence. For small angles of incidence, say 40 degrees or less for the blue, the approximate angle for the red can be found by multiplying the blue angle by the ratio of wavelengths. As an example, if you were using a HeCd and a HeNe, as many holographers do, and your 442 light was set at 40 degrees from the normal, then the 633 light would be at442/633*40=28 degrees. This is only 1.3 degrees from the correct value or about 5% error,which is not enough to cause trouble. This little trick could also be compared to bathing a table in a constant temperature oil bath,which is sort of the brute force method of compensating for table drift. It might also be compared to buying a $30,000 research grade invar table, which also compensates for thermal drift by not having any to begin with. In any case, no matter how you look at it, if you have a thermal drift problem, and it is primarily the steel table that is growing 1 or 2 microns in a 20 minute exposure,then lock those fringes and relax. If you can't lock them directly then at least lock down the section of the table that you are using by building a secondary locking circuit. If you need a locker, I know of two manufacturers in this area, I haven't made a locker myself since 1983 but I use one frequently and consider it essential absolutely gotta have tooling. Fringe locker manufacturers:<br> *Inovar Devices inc,<br> ph (435) 245-5061, fax (435) 245-6948 *Excalibur Engineering,<br> ph (435) 755-9221, fax (435) 755-9321 <br> <br> Last modified on 8/14/98 [[Category:Rallison]] 16c8e189d191bfd318d750d6b521ab3950515529 0 827 1692 2013-04-23T02:09:26Z Admin 0 wikitext text/x-wiki === Description, Use and Construction of the HOEs in this Kit === &lt;a href="http://web.archive.org/web/20080706200158/http://www.xmission.com/~ralcon/main.html#ordering"&gt;Ordering Information&lt;/a&gt;<br> ''Price per RK8 kit: $96 plus $4 S+H<br> Price per individual HOE: $20 incl S+H<br> We accept orders by company POs, phone, e-mail or fax.<br> Pay by Check, VISA/MC, C.O.D., Cash or Barter.<br>'' For inquires of any kind, contact lab director {| border="1" |- | [[Image:h1.gif]] | Off Axis Interferometric Zone Plate (IZP) - This unit has a focal length of 25 cm @ 633nm and reconstructs with a collimated wave introduced 20 degrees off axis. The focused spot will appear 20 degrees off axis also for a total diffraction angle of 40 degrees. It was made @ 488 nm but has few aberrations because it was contact copied from a master that was made at 633 nm. The master was made in a silver grain film that was cleared and processed like dichromated gelatin (DCG) to reduce scatter at the copy wavelength. The copy is in 8 microns of DCG sandwiched between two pieces of thin glass. |- | [[Image:h2.gif]] | Planer Gratings, Low Spatial Frequency - These units are made by interfering two collimated waves at small angles. The small angle low spatial frequency samples, (approx 100 l/mm) diffract with many orders present over a few degrees. They are similar to sinusoidal surface phase gratings in power spectrum and exhibit only a small Bragg selectivity. The power distribution is a function of the phase modulation which is in turn dependent on the available index modulation. As the spatial frequency goes above 500 l/mm the Bragg selectivity becomes strong and a single order dominates. These gratings are made in DCG in the range of 12 to 20 microns and each one is an original or first generation grating exposed at 488nm. |- | [[Image:h3.gif]] | Planar Gratings, High Spatial Frequency- A spatial frequency is considered high when the grating spacing is about equal to the wavelength being used. In the visible region this is around 2000 lines/mm. Higher orders are either not possible or are very weak in this range and diffraction efficiency is dependant on polarization as well as modulation, thickness, wavelength and angle. Volume phase gratings can also suppress higher orders even at low spatial frequencies if the thickness is many times the grating spacing. If it is thick in this sense it is said to have a high Q. The sample in this kit would be considered medium thick at 5 to 8 microns and of moderately high frequency at 2234 l/mm. |- | [[Image:H4.gif]] | Blazed Binary Optic Array - This is a set of six small blazed zone plates. Two of them are negative with focal lengths of 25 cm and two are positive with the same focal length. The other two are positive with focal lengths of about 75 cm. These were computer generated using a custom program written in POSTSCRIPT language which we call ZONE. The program writes a geometric zone plate pattern and fills the region between zones with up to 20 shades of grey which are printed as variations in dot density at 300 or 600 dots per inch. The output on paper was photoreduced in a common 35 mm NIKON camera using KODAK 5052 TMX negative print film. The next step was to expose a 3 micron layer of photo resist with a mercury arc lamp through the negative master which produced the desired positive blazed phase pattern. The resist master was then replicated in epoxy and the embossed copies in this kit were made by chemically softening a piece of cellulose acetate and pressing it against the epoxy master to cast a positive impression. The originals were 8 inches in diameter but were reduced about 30 times in the camera. The 25 cm focal length was generated by plotting 45 zones with 10 shades of grey and the long focal length came from a print of 15 zones with 20 shades of grey. The surface roughness is from contamination on the photo resist and will unfortunately scatter some of the input light and some moire artifacts are visible indicating that we should print the originals at a higher resolution than 300 dpi. The dispersion is low due to the small number of zones copied so white light may be used with these optics. Blazed zone plates exhibit good first order efficiency when the blaze depth produces a full wavelength of phase shift. These samples are close to correct and have very weak second orders at shorter focal lengths as well as fairly low minus first order. Outputs are easily observed on a white card by imaging a clear light bulb at a distance greater than 2 meters. |- | [[Image:h5.gif]] |Powered Holographic Reflector - These optics are produced by interfering a plane wave on one side of the film with a spherical wave from the other side. They are convex mirrors on one side and concave on the other. The micro structure resembles a layered reflective zone plate, the layers give it wavelength selectivity in the same fashion as a multilayer dielectric laser mirror and the zones give it angular dispersion. If there are many uniform layers or planes then a narrow spectral band is reflected and dispersion is only observed as an artifact in the transmitted light. The unit found in this kit is one of fairly short focal length and is easy to use in white light to observe off axis aberrations. It is not very narrow band and will show both longitudinal and lateral dispersion. The DCG is about 8 microns thick and has been processed to have a chirp in the spacing of the planes as well as a gradient in the index of modulation. The processing makes it behave as if it were thinner than it is. |- | [[Image:h6.gif]] |Conformal Holographic Reflector - These devices have no dispersion but can be made to have bandwidths of from 8 to 200 nm by choosing the appropriate thickness and process. They are in every way nearly identical to multilayer dielectric coatings. As the angle of incidence goes off normal the reflected wave goes toward the blue. The unit in this kit is a medium bandwidth reflector made in an 8 micron layer of DCG by the "air gate" method. It was held in laser light by hand in such a way that some of the light passing through would reflect back on itself at an angle and produce planes conformal to the film surface. The unstable hand holding is sufficient to spoil the spatial coherence of the laser resulting in a stable interference pattern only in a small volume near the film surface. This effectively suppresses the formation of diffracting structures that would otherwise result from multiple surface reflections. These devices are sometimes called notch filters. |- | [[Image:h7.gif]] |High Gain Holographic Diffusing Screen - These are projection screens that have precisely defined energy windows. The projected image is only visible and bright when it is originating from the correct angle and is of the correct wavelength. Even then it can only be seen when the eyes are positioned in the energy box or output pupil of the system. Otherwise it is a slightly hazy piece of clear glass. These units are made by projecting a diffuser through an aperture onto the film from one side and then introducing an appropriate reference wave on the other side. The reference wave for this sample was converging to a point about half a meter away. At arms length it should produce a bright eye box when illuminated with a white light diverging from a point just out from the right shoulder. This is an effective screen for stacking visual inputs since it is nearly invisible when not illuminated correctly. It also concentrates the projected light in a small area making possible the use of lower power projection sources. The sample in this kit is made in 8 microns of DCG at 488nm and processed to reflect green light. |- | [[Image:h8.gif]] |Holographic Scanner, 'One Shot'- This is a small 8 facet deflector intended for use in a hand held Bar Code Scanner. At 633 nm it accepts an input beam 5 degrees off normal and diffracts at 30 degrees off axis where it focuses at 4 different ranges between 200 and 400 mm from the deflector. It is unique in that it can be copied at 488 nm with a single on axis exposure. The master was made one facet at a time at 633 nm in Agfa film and converted to a clean gelatin hologram. Copies are made in DCG of about 5 micron thickness. The thin film and low spatial frequency results in low angular and polarization sensitivity over the scanned angle but also causes losses to a negative order. It can be glued to the end of a stick or mounted on a motor to demonstrate how a section of a zone plate can deflect light. |- | [[Image:h9.gif]] |Optical Interconnect HOE, -Any optical device that connects a source of photons with one or more detectors is an optical interconnect. In electronic circuits, clock pulses are sometimes made to modulate a diode laser which in turn broadcasts the pulse through free space to other parts of the device or circuit. The optical interconnect included in this kit is of appropriate dimensions to connect circuit boards or components on a board with each other. It is of a general design, made up of individual gratings or zone plates arranged side by side or "spatially multiplexed". It could connect a clock laser with 40 detectors, however it was originally designed to address angularly multiplexed pages in a photorefractive Holographic memory. Again this HOE has been fabricated from 10 microns of gelatin, in a sandwich of two pieces of glass. The method of construction was simple step and repeat, the machinery used to change angles between exposures is made from precision rotary tables and a single mode fiber optic system. The fiber is easily positioned any where in space to serve as a point source and it carries blue-green light from an Argon laser which is necessary to generate fringes in the gelatin. Plane Gratings have been formed in the sample but plane or powered reflectors are also possible to form with the same hardware. The gelatin is thick enough to allow volume multiplexing of each individual cell. As many as 25 individual overlapping exposures have been made in this film with only a small change in angle between exposures. This HOE can act like a faceted lens that has been cut in half and glued back together to yield two focused spots. The forty facets will cause an incoming plane wave to divide into two sets of 20 little plane waves that cross at two common planes about 38mm from the HOE surface. Encoding of information and images can be done with this type of HOE where the encoded information only appears on a specifically designed plane at a certain distance and with a certain color of light. Certain kinds of matrix operations can be made with combinations of these Hoes combined with spatial light modulators. Variable or reconfigurable interconnects may be made with the same components. |} '''''Last modified on 10/1/97''''' [[Category:Rallison]] 7e421f28bf576c7d00c39811da444ed8ae7d15a6 0 828 1694 2013-04-23T03:01:00Z Admin 0 /* Holography */ wikitext text/x-wiki ==== Diffractive Optics Family ==== [[Image:Doptics.gif|center]] ==== What can you do with a wavefront? ==== {| cellspacing="5" |- valign="top" | [[Image:whatdo1.gif]] | [[Image:whatdo2.gif]] |} *Diffractive elements can be single-order or multi-order *Patterning resolution x Area (SBWP) is a measure of absolute design freedom *Phase encoding techniques provide the effective design freedom *Very large SBWP can be made by combining holographic recording with computed DOEs ==== Diffractive Optical Element Basic Functions ==== [[Image:does.gif|enter]] ==== Application Examples ==== *Beam-combiners for display systems *Laser scanners *Low noise and high performance diffraction gratings *Asphere testing elements *Spectral notch filters *Holographic laser optical heads *Optical interconnections in microelectronics *Wavefront sampling *Wavefront transformation-diffusers *Solar concentrations *Wavelength multiplexers/demultiplexers *Various unique laser optical elements ==== HUD with combiner laminated into the windshield for Volkswagon ==== [[Image:car.gif|center]] ==== Multi Order Super HOE Scanner ==== [[Image:suprhoe.gif|center]] ==== Potential Advantages Of Holographic Disk Scanners ==== *Simpler optical arrangement *Larger tolerances for wobble *Less air turbulence *Each facet can have a different focal length *Lower production cost per unit *Scan angle is independent of the number of facets ==== Aberration-Corrected HOE Grating For Spectrometer ==== [[Image:abrcorfs.gif|center]] ==== Interferometric Testing With A Computer-Generated Hologram ==== [[Image:comgenho.gif|center]] ==== Spectral Filters ==== [[Image:spctfltr.gif|center]] '''Advantages of Holographic Spectral Filters''' *Easy fabrication of large filters *High efficiency *Parallel layering is not a constraint *Free from extranious passbands ==== Colour Combination/Colour Separation ==== [[Image:colour.gif|center]] ==== Three Beam Optical Pickup For Compact Audio Disk Player ==== [[Image:cdplayer.gif|center]] ==== Optical Interconnections in Microelectronics ==== [[Image:opintmcr.gif|center]] ==== Fiber Optic Couplers ==== [[Image:fiberopc.gif|center]] ==== Wavefront Sampling of High Power Laser ==== [[Image:hipowlsr.gif|center]] ==== Wavefront Transformation System ==== [[Image:wavetran.gif|center]] ==== Faceted HOEs ==== [[Image:faceted.gif|center]] ==== Directional Diffusers ==== [[Image:dirdiff.gif|center]] ==== Solar Applications ==== [[Image:solarapp.gif|center]] ==== Wavelength Multiplexing/Demultiplexing ==== [[Image:wavelngt.gif|center]] ==== The Basic Optical Processor ==== [[Image:basoppro.gif|center]] ==== Anti-Reflective Structures ==== [[Image:antiref.gif|center]] *As the grating period gets smaller, the diffraction angles increase *Ultimately, gratings have only zero order transmitted and zero order reflected *Tailoring duty cycle and etch depth one can control the power in these two remaining orders *This is the same as an impedance match in electricity and magnetism ==== Concept For Holographic Night Goggles ==== [[Image:niteggls.gif|center]] ==== Holography ==== '''Advantages''' {| |- |[[Image:holo1.gif|center]] | *Images to a point with no aberrations *Aberration control possible *Highly dispersive *Optical power on a flat surface *Off-axis geometry *Can be transmissive or reflective *Narrowband response *Can be replicated |} '''Disadvantages''' {| |- |[[Image:holo2.gif|center]] | *High dispersion *Large aberration away from construction conditions *Efficient over small wavelength band *Limited design flexibility *Difficulty with control of holographic emulsions |} ==== Advantages of HOE Diffraction Gratings (HOEDGs) ==== {| border="1" |- ! <u>Property</u> ! <u>Classical Gratings</u> ! <u>HOEDGs</u> |- valign="top" | Efficiencies | 60 to 99% | 50 to 90% (surface relief only)<br>Efficiency at blaze is lower but the efficiency curve is flatter |- valign="top" | Ghosts | At best 10^-5 (usually 10^-2) of parent line | No ghosts at all |- valign="top" | Scattered light | At best 10^-5 to 10^-6 at 5Å of laser line in visible | At best 10^-6 to 10^-8 at 5Å of laser line in visible |- valign="top" | Size | In general standard sizes are limited to 8x8" | Up to [[Image:phi.gif]] 17", but can be larger |- valign="top" | Number of grooves | Maximum 3600 lines/mm (There are rare exceptions.)<br>Scattered light increases drastically with density | Up to 6000 lines/mm<br> No increases of scatter with groove density |- valign="top" | Optical power | No | Yes<br>Volume HOEs can diffract 99% @ Bragg angle and center [[Image:lambda.gif]]. |} ==== Single Element Dispersions Showing Hybrid Achromat Possibilities ==== [[Image:sngledis.gif|center]] ==== Comparisons of Fabrication Methods Of Diffractive Optics ==== {| border="1" |- ! <br> ! Diamond Turning ! Direct-Write ! Holographic or Photo-Lithography ! Embossing ! Injection Molding |- ! Practical production volumes | 10⁰ ~ 10² | 10⁰ ~ 10² | 10⁰ ~ 10⁵ | 10³ ~ 10⁵ | 10³ ~ 10⁷ |- ! Initial tooling costs | low-moderate | low | moderate-high | low-moderate | high |- ! Precision | low-moderate | good-excellent | excellent | moderate | moderate |- ! Materials | metals, plastics | glasses, semiconductors | glasses, semiconductors | plastics | plastics |- ! Volume production costs | high | high | low-moderate | low | low |} ==== Direct Laser Writing ==== [[Image:dir.gif|center]] *Spot sizes ~1 - 5um *Tightly Focuses, modulated He-Cd or Argon-ion laser scanned across photresists surface *Up to 256 phase levels *Serial Process *Difficult to accurately transfer structure into substrate *Direct ablation of polyimide layer on substrate using an excimer laser is also possible *Pattern can be transferred to a VHOE by processing in a 4f optical processor. ==== Photoresist Processes For Lithography ==== [[Image:photo.gif|center]] ==== Spin Coating Photoresist ==== [[Image:spincoat.gif|center]] ==== Replication Methods ==== [[Image:repmeth.gif|center]] ==== 3 Step Conversion of Volume HOE to Surface Blazed HOE ==== [[Image:3step.gif|center]] ==== Laboratory Optical Test Apparatus ==== [[Image:labtest.gif|center]] ==== Rotating Slit Scanners (Beam Scan) ==== [[Image:rotslit.gif|center]] *Narrow, rotating slit is scanned through pattern *Measure irradiance profiles with ~micron lateral precision *Slit widths down to 1 um *Scan areas over 10 mm are possible *Measurement of both near and far-field diffraction patterns *Both 1-D and 2-D scans can be performed ==== Scatterometer ==== [[Image:scattm.gif|center]] *Measures irradiance patterns from DOE's by scanning a detector and pinhole *Scanning and data acquisition is computer controlled (LabView™ software) *Precision depends on pinhole size and step-size of motorized stage *Slow process *Can be difficult to align scan axis ==== Ronchi Rule -- Gaussian Spot Sise Measurement. (Lee Dickson) ==== [[Image:ronchi.gif|center]] *do = 1/e² spot *w = bar width *K = pmin/pmax *do/w = 2.2K + 1 Side view of ruling in beam ==== An Electromagnetic Shutter From A D'Arsenual ==== [[Image:shutter.gif|center]]<br>Shutter is silent and can easily be configured to close after accumulating a preset energy per unit area. ==== Hologram Exposure -- Single-Beam With Nonconformal Mirror ==== [[Image:nncnmirr.gif|center]]<br> Introduced by Yuri M. Denisyuk in early 1960s. ==== Single Beam Frame Using All Second Surface Mirror Without Ghosts (from Saxby) ==== [[Image:brewster.gif|center]] ==== Lloyd's Mirror ==== [[Image:loydsmir.gif|center]] ==== Gravity plateholder (after Abramson⁹ For NDT Apps ==== [[Image:gravity.gif|center]] ==== Film Holder With Xylene Well (after Benton, 1960s) ==== [[Image:filmhold.gif|center]] ==== Full-Aperature Transfer Hologram ==== [[Image:focusopt.gif|center]] ==== Rainbow Hologram (Benton, 1965) ==== [[Image:rainbowh.gif|center]] ==== Holographic Stereogram, after DeBitetto, 1968-69 ==== [[Image:debiteto.gif|center]] ==== 35 mm Holocamera by David Rowley ==== [[Image:holocam.gif|center]] ==== Contact Printing (copying) Of Transmission Or Reflection Holograms ==== [[Image:ctcprnt.gif|center]] ==== Secondary Holograms Formed By Scattered Light In A Construction Beam ==== [[Image:secndary.gif|center]]<br> Any stray or scattered light can combine with a construction beam to form secondary transmission and reflections holograms ==== Secondary Holograms Formed By Surface Reflections ==== [[Image:surfrefl.gif|center]]<br> The reflection portion of construction wave 1 combines with construction wave 2 to form a Transmission hologram ==== Prevention Of Secondary Holograms Formed By Surface Reflections ==== [[Image:orevsd.gif|center]] ==== Spurious (secondary) Holograms ==== [[Image:spurius.gif|center]] *Desired hologram: **Reflection hologram AB *Spurious holograms: **Reflection hologram AA1 **Reflection hologram BB1 **Reflection hologram A1B1 **Transmission hologram AB1 **Transmission hologram A1B ==== Prevention of Secondary Holograms ==== [[Image:prvntsho.gif|center]] ==== Michaelson Interferometer, Table Check, Fringelocker Check ==== [[Image:micinter.gif|center]] ==== Unique Characteristics Of HOEs ==== *Perfect imaging between two points for a single wavelength *Useful in unusual (I.E., not in-line) geometries *Shape independent (I.E., flat surfaces can have optical power) *Extremely dispersive (effice v-number of -3.45) *Angle selection *Wavelength selective *Multiple functions *Multiple elements in the same aperture *Compact and light weight *Relatively inexpensive - low cost "photographic" replication ==== Requirements on Construction Optical System ==== *Hight quality optical elements *Minimize multiple reflections between surfaces of construction optics and hologram substrate *Scattered light should be prevented from falling on hologram plate *Mechanical and thermal stability during exposure *Proper coherence length *Polarization of two recording beams should be maintained properly *Active fringe stabilization system for long exposures ==== Form Birefringence ==== [[Image:birefrin.gif|center]] *Subwavelength gratings behave somewhat like biaxial crystals *As the period gets small relative to the wavelength, we can calculate an equivalent dielectric constant or index of refraction (n) ''Last modified on 7/21/99'' [[Category:Rallison]] ea080d11d3b9368b93fd57997704e0f133f95e53 0 831 1704 2013-04-23T03:15:30Z Admin 0 /* Advantages of DOEs */ wikitext text/x-wiki Also see a sample of [[Equatoins|common DOE surfaces]]. *Complete Spectrograph designs and brassboard prototypes, diffractive component production for the same *Transmission gratings from 10 to 4000 l/mm, plane, slanted, crossed, cophasal, multiplexed spatially or stacked in volume from spectroscopic instrument to light show quality, in DCG, photopolymer, resist or plastic replicas. *Powered transmission HOEs of f/2 or greater with low aberrations, apertures to 1 meter and wavelengths from 355 to 1064 nm, for LIDAR applications. *Off axis Multifocus hololens and flys eye arrays, optical interconnects and general multiplexed powered optics. ==== "Catadioptric HMD" ==== {| |- |[[Image:cathyb1.gif|center]] | *Narrow Notch filters from 400 to 900 nm, 10 to 40 nm bandwidth, Optical densities to 5 or 6 in 30 microns of DCG. *[[Directional diffusers]], dipixelators and homogenizers in virtually any configuration, (design, fabrication, and production). *HUD and HMD components including conformal multiwavelength combiners on CR 39 or glass of any radius. *TIR gratings for photon buckets, edge lighting, polarizing. |} ==== "Transmissive Grating Spectrograph" ==== {| |- |[[Image:graph3.gif|center]] | *Bidiffringent polarization separator that works in a Wollaston configuration and broadband planer polarization splitters. *Complete ZEMAX optical designs including binary surfaces, masks and phase only replicas in volume or surface media. *Hybrid refractive/diffractive design and fabrication. |} ==== "Powered Laser Scanner" ==== {| |- |[[Image:graph4.gif|center]] | *In-house lithographic photoreduction for some DOE production. *Conversion of customer generated amplitude masks to efficient phase DOEs and HOEs. *IR gratings for 3 to 12 microns in slumped amorphous IR glasses. *Addition of high frequency carriers to low angle CGHs. |} '''The odds are in your favor, that we can make the HOE you need.''' == Advantages of DOEs == #Simultaneous performance of several functions such as [[Equations#Holographic Deflectors (hologons)|deflection]], focusing, filtering, and collimating as in bar code scanners. #Parallel performance of similar or different functions such as the multifocus Hololens array for parallel pattern recognition. #Ease of stacking elements such as multi-wavelength solar reflectors. #The formation of optics on curved substrates such as heads up displays on visors or curved windshields. #Weight and volume of a holographic system is likely to be less than refractive optics, especially for large apertures. #Ease of replication makes production fast, inexpensive and relatively simple. '''''Last modified on 9/16/97''''' [[Category:Rallison]] c1a10806b51f7ee8cc5fd50429581a66292b1233 0 597 1858 1345 2013-04-23T22:26:53Z Admin 0 wikitext text/x-wiki [http://www.ultimate-holography.com/ Ultimate] [[Category:People]] bb99e9bc98c56f1f835b1b379a287e2b1407b278 0 596 1856 1343 2013-04-23T22:27:24Z Admin 0 wikitext text/x-wiki [[Image:YDenisyuk.jpg]] Died at the age of 88 in May 2006. Yuri Denisyuk invented single beam reflection holography. ===A Memorial by Ed Wesley=== {| |[[Image:YDenisyuk2.jpg]]|| “Now maybe the girls will notice me!” quips Yuri Denisyuk, proudly displaying the Cyrillic Danger: Laser Radiation sign presented to him by the local Coherent Laser sales rep at his first visit to Lake Forest College in 1989. This is my favorite image of one the great gods of Mt. Holympus, personified as everyone’s favorite grandfather with a wacky sense of humor. After all, it was a science fiction story that inspired him to invent his own style of wavefront reconstruction! |} [[Category:People]] 22e9bd8e0896573e79d55451e829b418d246c44e 0 515 1824 1181 2013-04-23T22:28:00Z Admin 0 wikitext text/x-wiki Stephen Benton [[Image:Benton.jpg]] In Memory: (December 1, 1941 - November 9, 2003) Allen Professor of Media Arts and Sciences Director, Center for Advanced Visual Studies Group: Spatial Imaging [http://www.media.mit.edu/~sab Benton at MIT]] Biography Stephen Benton was best known as the inventor of the white-light "rainbow" hologram, most often seen on credit cards and magazine covers. He was also known for the work he and his group did to create the world's first real-time interactive holographic video system. He was a prolific author and held multiple patents in optical physics, photography, and holography. Benton headed the Lab's Spatial Imaging research group. While an MIT undergraduate, Benton worked with Harold "Doc" Edgerton in the famous "Strobe Lab," and received his BS degree in electrical engineering in 1963. He continued his studies at Harvard University, receiving a PhD in applied physics in 1968, and remained at Harvard until 1973 as its first assistant professor of applied optics. He was associated with laboratories of the late Edwin Land at Polaroid Corporation since his undergraduate days, and returned there to establish an imaging physics laboratory, where he did much of the early work on white-light viewable holograms, and explored other applications of lasers to photography. Curriculum Vita 1999 E. Rudge ('48) and Nancy Allen Professor of Media Arts & Sciences Head, Spatial Imaging Group, Media Laboratory Director, Center for Advanced Visual Studies (CAVS) Graduate Officer, Program in Media Arts & Sciences Massachusetts Institute of Technology 1999 Vice President, Society for Imaging Science & Technology 1996 Director, Center for Advanced Visual Studies (CAVS) 1990 - 1993 Board of Governors, Int'l Soc. Optical Eng'g (SPIE) 1987 - 1994 Founding Head, MIT Program in Media Arts & Sciences 1987 - 1992 Board of Trustees, Museum of Holography, New York 1984 Founding Faculty, Media Laboratory, MIT 1982 Founder, Spatial Imaging Group, MIT 1980 - 1984 Chairman, US National Committee for the International Commission for Optics 1980 - 1983 Visiting Scientist, MIT Laser Research Center 1979 - 1984 Visiting Committee, International Museum of Photography at George Eastman House 1978 - 1981 Board of Directors, Optical Society of America 1976 - 1977 President, Optical Society of America, New England Section 1973 - 1982 Senior Scientist, Polaroid Corporation 1968 - 1973 Assistant Professor of Applied Optics, Harvard University PUBLICATIONS: Articles: 46 Patents: 14 EDUCATION: Bachelor of Science in Electrical Engineering, MIT, 1963 Master of Science in Engineering, Harvard University, 1964 Doctor of Philosophy in Applied Physics, Harvard University, 1968 PROFESSIONAL SOCIETIES Optical Society of America (Fellow, former Director) Society for Imaging Science & Technology (IS&T/SPSE) (Fellow, Vice President) Institute of Electrical & Electronic Engineers The International Society for Optical Engineering (SPIE) (Fellow, former Director) Society for Information Display (SID) Holographic Display Engineers & Artists Club (HODIC, Japan) [[Category:People]] 8628a920153d08061ca7faeecf10edcd222f2d45 0 494 1802 1139 2013-04-23T22:28:36Z Admin 0 wikitext text/x-wiki [[Image:SZharkiy.jpg]] Sergey Zharkiy graduated from the Moscow State University, Faculty of Physics with a MS (Master of Science) in Physics in 1999. He studied lasers and holography at the International Laser Center of Moscow State University. He took part in scientific conferences with his articles on holography and laser applications. Sergey Zharkiy is an author and developer of [http://www.holography.ru Holography.Ru] web site. He wrote and translated many articles for this web site. Sergey also designed and made several art holograms for gallery of Russian Holographic Studios. Sergey Zharkiy took part in development of compact holographic kit for amateur holographers. He is also author and director of educational film (DVD) on holography. [[Category:People]] 88db2fc869fd4fd4472efa13d4efd72b7679dda2 0 485 1796 1121 2013-04-23T22:28:54Z Admin 0 wikitext text/x-wiki [http://rudieberkhout.home.mindspring.com/home.htm Rudie Berkhout] Rudie Berkhout was a Artist/Holographer from Leeds NY. He had an extensive list of publications about holography and regularly exhibited his work. Born in Amsterdam, Berkhout came to the United States in 1974 with a background in engineering and lighting to study at the New York School of Holography. He later researched white light holographic techniques and pulsed holography at the New York Art Alliance laboratories. He created the first flat display system for holographic movies (Integral holography or holographic stereograms first developed by Lloyd Cross) while at the Holographic Film Company in New York (founded by cinematographer Hart Perry). Until this time, holographic stereograms had been viewed only in the round. Berkhout also designed and built a time-lapse recording system to enable artists to capture as much as four hours of movement in a single hologram. A major contribution to the medium was his work in color control and image multiplication which resulted in his breathtaking "Twelve Milliwatt Boogie" first exhibited in 1979 at the Museum of Holography, New York. This stunning piece set a standard in white-light transmission holography with its boldly-colored geometric figures floating in three-dimensional space. Rudie Berkhout passed away from a heart attack on Tuesday 16 September, 2008. [[Category:People]] d9f522a19f3468bdf33c7af7f08d8ec2d812c99e 0 482 1792 1115 2013-04-23T22:29:12Z Admin 0 wikitext text/x-wiki [[Category:People]] 77f3967bfd415c1f7e93a4c290d247350ea0775c 0 457 1766 1065 2013-04-23T22:29:38Z Admin 0 wikitext text/x-wiki [http://www.pearljohn.co.uk/holography.html Pearl John] [[Category:People]] 2464ce0d0f66dec6f7824ab68e8ccf6534aa0c90 0 433 1756 1017 2013-04-23T22:30:04Z Admin 0 wikitext text/x-wiki [[Image:Mmueller.jpg]] Martin Mueller Born and lives in Zurich, Switzerland. Used to work as a freelance journalist, essay writer and translator. Caught the holography virus (1980) when writing an essay on holography (which put emphasis on forerunners in the arts mainly). Run a small holography business with Ralph Kuehne for more than ten years. 1998 begin of friendship and cooperation with Sergio Oliveira (Sao Paulo, Brazil), which led to the development of a new photopolymer system [http://www.polygrama.co.nr/ Polygrama]. [[Category:People]] dd13a012f166b80a4f270daa41cc8a4b2fe753a9 0 400 1736 952 2013-04-23T22:30:45Z Admin 0 wikitext text/x-wiki [[Image:JUpatnieks.jpg]] Director of Applied Optics Ann Arbor, Michagan Professor, Electrical and Computer Engineering Department University of Michigan Mechanical Engineering and Applied Mechanics Department University of Michigan Born: May 7, 1936, Riga, Latvia ---- ==List of Patents== *3,506,327 Wavefront Reconstruction Using a Coherent Reference Beam, 1970 *3,532,407 Spatial Frequency Reduction in Holography, 1970 *3,539,241 Method of Imaging Transparent Objects with Coherent Light, 1970 *3,545,835 Two-Beam Holography with Reduced Source Coherence Requirements, 1970 *3,548,643 Holographic Vibration Analysis Method and Apparatus, 1970 *3,580,655 Wavefront Reconstruction", 1971 *3,637,313 Method of Imaging Transparent Objects with Coherent Light, 1972 *3,677,617 Technique of Holographic Data Reduction Utilizing an Additional Diffusing Structure During Reconstruction, 1972 *3,748,048 Method of Detecting Changes in Specular Surface, 1973 *3,838,903 Wavefront Reconstruction, 1974 *3,894,787 Holograms, 1975 *4,012,150 Holographic Light Line Sight, 1977 *4,057,317 Hologram Projector, 1977 *4,223,975 Aberration Correction of Magnified Holographic Images, 1980 *4,277,137 Coherent Optical Correlator, 1981 *4,643,515 Method and Apparatus for Recording and Displaying Edge- Illuminated Holograms, 1987 *4,711,512 Compact Head-Up Display, 1987 *5,151,800 Compact Hologram Displays and Methods of Making Compact Hologram, 1992 *5,483,362 Compact Holographic Sight, 1996 [[Category:People]] fab1ae3a98f5dd593b189893407d1f1c6049ed11 0 397 1730 946 2013-04-23T22:31:00Z Admin 0 wikitext text/x-wiki Sorry, I had more of a holography history for me then a biography. I have an AA degree from a local Community College with an emphasis in Computer Science. I furthered my education at University of Maryland with Physics, Math and Computer Classes. I am a Microsoft Certified Systems Engineer and presently design Wide Area Networks. I have worked at North East Holographics and responsibilities included: Design, configure and produce H1 multi-channel rainbow master holograms for replay with a HeCd laser using a large frame Argon Ion laser. Design, configure and produce H2 rainbow copy holograms in Photoresist utilizing a fringe locker to help with stability during the long exposure times and using a HeCd laser. Fabricate Photoresist emulsions on glass plates. Implemented quality control of Photoresist plates. Silverized the Photoresist plates with an atomizing spray system. Built, maintained and controlled variables for producing different types of Nickel Shims made from the Silverized Photoresist plates. Built, maintained and operated a complete wide format Embossing Printer used to hot stamp nickel shim hologram in foil backed plastics. I have also been involved with amateur holography since 1982 working with Silver Halide. Currently and for the past 3 years I have been concentrating my efforts in working with Fabrication and production of Dichromated Gelatin holograms implementing a variety of techniques formulas and geometries. I have moved from the basement to a dedicated lab. [[Category:People]] 5b3e6ebd57b0117036461dcb4662ba18df94a25a 0 284 1722 416 2013-04-23T22:31:16Z Admin 0 wikitext text/x-wiki [[http://www.hololab.com/ Ikuo's Web Site]] [[Category:People]] 2b4520346d0ce3866126b16e671251968a425fe1 0 249 1688 346 2013-04-23T22:31:35Z Admin 0 wikitext text/x-wiki Greg Quinn worked at the National Physical Laboratory between January 21st 1974 and September 15th 1985 in the holographic interferometry group (at that time, part of the Department of Mechanical and Optical Metrology). Working under Tony Ennos, Eddie Archbold and finally Dave Williams, he created many display holograms that have been presented both internally and at national meetings since then. Following his time at NPL, he studied biochemistry at Leeds, and gained his Ph.D. in molecular biology at Southampton University. Greg is currently principal investigator of the Mobile Data Visualization Lab at the San Diego Supercomputer Center, at the University of California San Diego. He's married with one son. [[Category:People]] ac2fbe21d0264a0b9bd06b1605bd75a6f26c6757 0 224 1670 296 2013-04-23T22:32:11Z Admin 0 wikitext text/x-wiki Emmett Leith (born in Detroit, Michigan, died December 23, 2005) was a professor of electrical engineering at the University of Michigan and the inventor of three-dimensional holography. Leith was educated at Wayne State University. Professor Leith and his coworker Juris Upatnieks displayed the world's first three-dimensional hologram at a conference of the Optical Society of America in 1964. In 1979, President Jimmy Carter awarded Leith with the National Medal of Science for his research. [http://en.wikipedia.org/wiki/Emmett_Leith Wikipedia] [[Category:People]] af528607d5742b0364291931a49306eea34dded6 0 218 1664 284 2013-04-23T22:33:00Z Admin 0 wikitext text/x-wiki [http://www.integraf.com Integraf] Dr. Tung H. Jeong (better known as "T.J.") is a professor emeritus at Lake Forest College, Lake Forest, Illinois, and has over 35 years of experience in holography. He has led the field of holography as researcher, innovator, consultant, and, most significantly, educator. Having authored numerous articles, T.J. is recognized as a leading scholar in holography. TJ's recent publications include an article published in Applied Optics, the most widely read international holography journal. Besides research, T.J. has also produced two motion pictures. One entitled, "Introduction to Holography," was sponsored and marketed by Encyclopedia Britannica. A teacher at heart, T.J. has been invited to lecture and teach seminars at over 500 universities, professional societies, and industrial sites in Europe, China, Russia, among other international locations. T.J. has also co-chaired international conferences on holography and optics in Russia, Bulgaria, and Hungary. Moreover, for nearly 30 consecutive years, T.J. has hosted holography workshops for novices and experts. In 1982, T.J. started the triennial International Symposium on Display Holography. His most recent symposium attracted over 120 scientists, artists, and businessmen from 18 countries. Together with Dr. Hans Bjelkhagen, a visiting scientist from Sweden, T.J. discovered technology that makes true-color holograms possible. T.J. is also credited with the discovery of cylindrical holograms, changing holograms from flat formats into images people could walk around and view from all perspectives. In 1973, T.J. shared in the development of the technology that created three-dimensional moving holograms and was the first to implement the use of optic fibers, making holograms simpler and less costly to make. In the business world, T.J. serves as a worldwide consultant to corporations in various industries to develop holographic solutions. For example, T.J. has worked extensively with DuPont on their development of holographic photopolymers. With the development of this technology, holograms is becoming a common part of people's lives. (Photo: Encyclopaedia Britannica Educational Corp., 1972) T.J. joined the faculty of Lake Forest College in 1963 and served as director of the Center for Photonics Studies. He came to the U.S. from China as a young boy in 1948. Upon graduation from Amarillo High School in Texas, he attended Yale University under a full-scholarship, and received his B.S. degree in physics and mathematics in 1957. He completed his Ph.D. degree in nuclear physics at the University of Minnesota in 1963. A member of many professional societies, T.J. is a Fellow of the Optical Society of America and the recipient of the Robert Millikan Medal from the American Association of Physics Teachers. He is also recipient, of the Saxby Medal of the Royal Photographic Society of Great Britain and the Lifetime Achievement Award from the International Holographic Manufacturer's Association. T.J. has regularly chaired of the annual conference Practical Holography - Materials and Applications, sponsored by the International Society of Optical Engineering (SPIE) and the Society for Imaging Science and Technology (IS&T), taking place in San Jose, California. In November 2005, T.J. was a keynote speaker at the Holopack Holoprint international conference in Shenzhen, China. [[Category:People]] 34457f65f776dcc73490aa1df8691ba2acad356e 0 166 1580 180 2013-04-23T22:33:22Z Admin 0 wikitext text/x-wiki The bio below was shamelessly pulled from Andres' home page and could use further editing. I have been involved in holography for quite some time. It started back in 1988 when I was in high school and needed to do some experiments for my school science fair week. At the time, all I had was a small 0.5mW HeNe from Metrologic that my grandfather bought for me after a very intense negation with him :), a limited supply of Agfa Holographic plates and one of the best resources of the time for the amateur holographer, the famous Holography Handbook by Fred Unterseher, Jeannene Hansen and Bob Schlesinger. The setup consisted of a sand box (as described in the handbook) resting on top of 4 inner tubes and 4 cinder blocks, some mirrors, lenses, Kodak D19 developer and a few other chemicals for development and bleaching (can’t remember the names). The process was very frustrating at the beginning. After using almost half the box of holographic plates, no hologram was obtained. You can imagine how wonderful it was when I was able to produce my first hologram. It’s a day I will never forget… I was only able to work with holography for a very limited period at that time and I was not able to do any holography work for 13 years. That all changed in 2003 when I met Michael Harrison. Susan, his wife, works with me and she used to bring Michael’s holograms to the office all the time. It didn’t take long for me to notice that and after talking with her decided to meet him. Well, suffice it to say, I got hooked instantly. Michael’s setup at his house is impressive and he was more that willing to help me get started again. This time though, things were a lot easier. First, I have another holographer that lives 5 minutes from my house, the internet, the holography forum for discussing anything holograhic with profesional and amateur holographers all over the world and last but not least, there is e-bay, the best source for equipment, lasers, optics, books, and anything relating to holography. My current setup is a lot more complex that my first one, it consists of an isolation table top built using a light weight material called Hexcel (a honeycomb material) sandwiched between three layers of steel sitting on top of inner tubes. A pair of 8” parabolic mirrors, spatial filter, magnetic bases to hold components, tons of lenses and mirrors and of course a laser (15mW HeNe). http://www.ghisays.net/default.php [[Category:People]] b1d91a4414e505caafe93d5cc5bc875f68bf717b 0 167 1582 182 2013-04-23T22:34:06Z Admin 0 wikitext text/x-wiki [http://www.apepper.com/ Andrew's Web Site] Andrew Pepper studied Fine Art in the UK, where he began working with projected light and 3-D light installations. During this period he saw his first hologram in Paris, at an exhibition organised by Jody Burns and Posy Jackson, at the American Cultural Centre, in the City. He thought this would be the ideal medium to use to document his installations in 3-D. On conclusion of his Fine Art course, he spent 2 years at the Museum of Holography, in New York, as a Fulbright Scholar, and it was there that he learned how to make holograms at new York Holographic Labs. It was some time before he felt comfortable using the medium - wanting to find an alternative to the amazing 3-D effect which had originally attracted him to the medium. When he returned to the UK in 1981 he began lecturing and writing on creative holography and starting to produce his own work, which has now been exhibited in solo and group shows world-wide. He also completed a PhD in Fine Art Holography, the first of its type to be awarded by the Fine Art Department of the University of Reading. During 1988 Pepper was awarded a Lionel Robbins Memorial Scholarship which allowed him to continue his PhD research and carry out extensive exploration in a specially built holography studio at Reading University. In 1991 he moved to Cologne to take up a 5 year post with the newly established Academy of Media Arts, which as part of its studio activities was offering Holography under the direction of German Artist, Professor Dieter Jung. During this time in Germany he was able to realise a project he had been working on for several years earlier and founded the Creative Holography Index, The International Catalogue for Holography, which provided a very high quality collection of material about artists working in the medium, as well as commissioning several leading writers to give their views on the development of the field. While at the Academy he was introduced to the Internet and world wide web and eventually began to ‘translate’ the paper publication into a digital one, making it accessible to a much wider audience. He has remained interested in this idea of digital publishing and delivered several papers on the subject at international conferences. 1996 saw him move back to the UK to organise and chair Art in Holography2, a major international symposium which attracted speakers and delegates from all over the world and concentrated entirely on the art of the medium. From 1999 - 2004 he was director of the Shearwater Foundation Holography program, established by Posy Jackson in 1987. Each year it provided 100,000 US Dollars to support and encourage creative holography, as well as honouring several artists with the annual Holography Award, given to outstanding practitioners in recognition of their major contribution to the field. Pepper is a visiting lecturer at the Nottingham Trent University, School of Art and Design. [[Category:People]] 6c114e2971fcad952401ccf4d382f9b90bc3477c 0 173 1594 194 2013-04-23T22:34:30Z Admin 0 wikitext text/x-wiki [http://www.lasart.com Lasart] [[Category:People]] 0e0c76a71d245a2d50d40b1263ef11260f55c880 0 211 1642 270 2013-04-23T22:34:56Z Admin 0 wikitext text/x-wiki from [http://Nobelprize.org www.nobelprize.org] Dennis Gabor – Autobiography [[Image:Gabor.gif]] I was born in Budapest, Hungary, on June 5, 1900, the oldest son of Bertalan Gabor, director of a mining company, and his wife Adrienne. My life-long love of physics started suddenly at the age of 15. I could not wait until I got to the university, I learned the calculus and worked through the textbook of Chwolson, the largest at that time, in the next two years. I remember how fascinated I was by Abbe's theory of the microscope and by Gabriel Lippmann's method of colour photography, which played such a great part in my work, 30 years later. Also, with my late brother George, we built up a little laboratory in our home, where we could repeat most experiments which were modern at that time, such as wireless X-rays and radioactivity. Yet, when I reached university age, I opted for engineering instead of physics. Physics was not yet a profession in Hungary, with a total of half-a-dozen university chairs - and who could have been presumptious enough to aspire to one of these? So I acquired my degrees, (Diploma at the Technische Hochschule Berlin, 1924, Dr-Ing. in 1927), in electrical engineering, though I sneaked over from the TH as often as possible to the University of Berlin, were physics at that time was at its apogee, with Einstein, Planck, Nernst and v. Laue. Though electrical engineering remained my profession, my work was almost always in applied physics. My doctorate work was the development of one of the first high speed cathode ray oscillographs and in the course of this I made the first iron-shrouded magnetic electron lens. In 1927 I joined the Siemens & Halske AG where I made my first of my successful inventions; the high pressure quartz mercury lamp with superheated vapour and the molybdenum tape seal, since used in millions of streeet lamps. This was also my first exercise in serendipity, (the art of looking for something and finding something else), because I was not after a mercury lamp but after a cadmium lamp, and that was not a success. In 1933, when Hitler came to power, I left Germany and after a short period in Hungary went to England. At that time, in 1934, England was still in the depths of the depression, and jobs for foreigners were very difficult. I obtained employment with the British Thomson-Houston Co., Rugby, on an inventor's agreement. The invention was a gas discharge tube with a positive characteristic, which could be operated on the mains. Unfortunately, most of its light emission was in the short ultraviolet, so that it failed to give good efficiency with the available fluorescent powders, but at least it gave me a foothold in the BTH Research Laboratory, where I remained until the end of 1948. The years after the war were the most fruitful. I wrote, among many others, my first papers on communication theory, I developed a system of stereoscopic cinematography, and in the last year, 1948 I carried out the basic experiments in holography, at that time called "wavefront reconstruction". This again was an exercise in serendipity. The original objective was an improved electron microscope, capable of resolving atomic lattices and seeing single atoms. Three year's work, 1950-53, carried out in collaboration with the AEI Research Laboratory in Aldermaston, led to some respectable results, but still far from the goal. We had started 20 years too early. Only in recent years have certain auxiliary techniques developed to the point when electron holography could become a success. On the other hand, optical holography has become a world success after the invention and introduction of the laser, and acoustical holography has now also made a promising start. On January 1, 1949 I joined the Imperial College of Science & Technology in London, first as a Reader in Electronics, later as Professor of Applied Electron Physics, until my retirement in 1967. This was a happy time. With my young doctorands as collaborators I attacked many problems, almost always difficult ones. The first was the elucidation of Langmuirs Paradox, the inexplicably intense apparent electron interaction, in low pressure mercury arcs. The explanation was that the electrons exchanged energy not with one another, by collisions, but by interaction with an oscillating boundary layer at the wall of the discharge vessel. We made also a Wilson cloud chamber, in which the velocity of particles became measurable by impressing on them a high frequency, critical field, which produced time marks on the paths, at the points of maximum ionisation. Other developments were: a holographic microscope, a new electron-velocity spectroscope an analogue computer which was a universal, non-linear "learning" predictor, recognizer and simulator of time series, a flat thin colour television tube, and a new type of thermionic converter. Theoretical work included communication theory, plasma theory, magnetron theory and I spent several years on a scheme of fusion, in which a critical high temperature plasma would have been established by a 1000 ampere space charge-compensated ion beam, fast enough to run over the many unstable modes which arise during its formation. Fortunately the theory showed that at least one unstable mode always remained, so that no money had to be spent on its development. After my retirement in 1967 I remained connected with the Imperial College as a Senior Research Fellow and I became Staff Scientist of CBS Laboratories, Stamford, Conn. where I have collaborated with the President, my life-long friend, Dr. Peter C. Goldmark in many new schemes of communication and display. This kept me happily occupied as an inventor, but meanwhile, ever since 1958, I have spent much time on a new interest; the future of our industrial civilisation. I became more and more convinced that a serious mismatch has developed between technology and our social institutions, and that inventive minds ought to consider social inventions as their first priority. This conviction has found expression in three books, Inventing the Future, 1963, Innovations, 1970, and The Mature Society, 1972. Though I still have much unfinished technological work on my hands, I consider this as my first priority in my remaining years. Honours Fellow of the Royal Society, 1956. Hon. Member of the Hungarian Academy of Sciences, 1964. D.Sc. Univ. of London, 1964, Hon. D.Sc. Univ. of Southampton, 1970, and Technological University Delft, 1971. Thomas Young Medal of Physical Society London, 1967. Cristoforo Colombo Prize of Int. Inst. Communications, Genoa, 1967. Albert Michelson Medal of The Franklin Institute, Philadelphia, 1968. Rumford Medal of the Royal Society, 1968. Medal of Honor of the Institution of Electrical and Electronic Engineers,1970. Prix Holweck of the French Physical Society, 1971. Commander of the Order of the British Empire, 1970. Married since 1936 to Marjorie Louise, daughter of Joseph Kennard Butler and Louise Butler of Rugby. From Les Prix Nobel en 1971, Editor Wilhelm Odelberg, [Nobel Foundation], Stockholm, 1972 This autobiography/biography was written at the time of the award and later published in the book series Les Prix Nobel/Nobel Lectures. The information is sometimes updated with an addendum submitted by the Laureate. To cite this document, always state the source as shown above. Dennis Gabor died on February 8, 1979. [[Category:People]] 84ae0ffd08879a9f96ad2c9a1dfc4ad0ea94c4d5 0 165 1578 178 2013-04-23T22:36:41Z Admin 0 wikitext text/x-wiki [[Image:AStephens.jpg]] [http://anait.com/ Anait's Web Site] Anait (Anait Arutunoff Stephens) was born in Berlin, Germany in 1922. On August 21, 1998, Anaït lost her battle against cancer in Santa Barbara, California, USA, in 1998. 1954 Instituto Nacional de Bellas Artes, Mexico, with Orozco Romero. 1958 Mexico City College, Mexico, with Toby Joysmith. 1964 University of California at Los Angeles, USA, with Dewain Valentine. 1971 School of Holography, San Francisco, California, USA, with Lloyd Cross. 1980 Museum of Holography, New York, USA, Artist-in-Residence. Professional Activities Lectures (selected) 1974 Studio lectures, Artist’s studio, Los Angeles, California, USA. 1977 Electro-Optics Seminar, Anaheim Convention Center, Anaheim, California, USA. 1978 Third Conference On Holography, USSR (the only woman and artist in attendance). Museum of Holography, New York, USA. 1980 Santa Barbara Museum of Art, Santa Barbara, California, USA. 1983 Studio lectures, Artist’s studio, New York, USA. 1986 The Royal Photographic Society Holography Group, London, UK. 1990 Chicago Art Institute, Chicago, Illinois, USA. 1991 Durand Art Institute, Lake Forest, Illinois, USA. 1992 Visiting tutor, Royal College of Art, London, UK. PUBLICATIONS Catalogues (selected) 1976 Through the Looking Glass, Museum of Holography, New York, USA. 1977 Theme and Variation, National Academy of Science, Association of Science – Technology Center, Washington, DC, USA. 1978 Alice in the Light World, Isetani Museum, Tokyo, Japan. 1979 ANAIT Retrospective 1966-1979, Museum Of Holography, New York, USA. 1983 Light Dimensions, Octagon, Bath, UK. 1984 Licht-Blicke, Deutsches Filmmuseum, Frankfurt/Main, Germany. 1987 Light Dreams, Kalamazoo Art Institute, Michigan, USA. 1991 Fiat Lux! Holografia, Asturias, Spain. 1991 Fourth International Exhibiton of Display Holography, Durand Art Institute, Lake Forest, Illinois, USA. Articles/interviews 1973 Blasco-Ibanez, “Down to the Sea in Sculpture”, Los Angeles Herald-Examiner Sunday Magazine, California Living. 1974 Melinda Wortz, “Los Angeles: Anait at Gallery 707”, Arts Magazine. 1978 Lincoln F. Johnson, “Defining, Evaluating Holography”, The Baltimore Sun. Anait, “My Art in the Domain of Reflection Holography” Leonardo Journal, Vol. 11 pp. 306-7. “A Letter to Leonardo”, Leonardo Journal, Vol. 11, pp. 351. 1979 William Wilson, Review, A-B Gallery, Los Angeles Times. 1980 James Wood, “Painterly Holography”, Artweek. 1981 Ricky Horton, “Anait: Holography as Art”, New York Arts Journal. 1987 Joan Crowder, Santa Barbara, News Press. OTHER INFORMATION 1972 Opened “Gallery 707”, Los Angeles. First gallery for women artists in LA. 1976 First solo art exhibit in the world in reflection holography: “Theme and Variation”. 1986 Listed in “Allgemeines Künstlerlexikon” (International Art Encyclopedia). [[Category:People]] 48e31b4762514320eef4cde7091998c836924ddc 0 215 1656 278 2013-04-23T22:37:38Z Admin 0 wikitext text/x-wiki [[Category:People]] 77f3967bfd415c1f7e93a4c290d247350ea0775c 0 217 1662 282 2013-04-23T22:37:54Z Admin 0 wikitext text/x-wiki [http://www.vilamedia.com/ VilaMedia's Web Site] [[Category:People]] ec0051c693e7a1868fc2b7eb823b89b362736ac3 0 244 1682 336 2013-04-23T22:38:44Z Admin 0 wikitext text/x-wiki [[Image:GLippmann.jpg]] French physicist who received the Nobel Prize for Physics in 1908 for producing the first colour photographic plate . He was known for the innovations that resulted from his search for a direct colour-sensitive medium in photography. Though born of French parents in Luxembourg, Lippmann grew up in Paris and was a bright but unruly student. Despite the fact that he never received his teacher's certificate, he was appointed professor of mathematical physics at the Sorbonne in 1883. He later was appointed head of the Sorbonne's Laboratories of Physical Research (1886). Lippman's scientific talents were varied, but he was best known for his contributions in the fields of optics and electricity. He did early, important studies of piezoelectricity (precursors of Pierre Curie's work) and of induction in resistanceless, or superconductive, circuits (precursors of Heike Kammerlingh-Onnes' validations). He also invented the coleostat, an instrument that allowed for long-exposure photographs of the sky by compensating for the Earth's motion during the exposure. In 1891 Lippmann revealed a revolutionary colour-photography process, later called the Lippmann process, that utilized the natural colours of light wavelengths instead of using dyes and pigments. He placed a reflecting coat of mercury behind the emulsion of a panchromatic plate. The mercury reflected light rays back through the emulsion to interfere with the incident rays, forming a latent image that varied in depth according to each ray's colour. The development process then reproduced this image, and the result, when viewed, was brilliantly accurate. This direct method of colour photography was slow and tedious because of necessarily long exposure times, and no copies of the original could be made. It never achieved popularity, therefore, but it was an important step in the development of colour photography. [http://nobelprize.org/physics/laureates/1908/lippmann-bio.html Nobel Prize's Biography of Gabriel Lippmann] [[Category:People]] b661a26aed2dbb5c070254dd164a9e1b7df987a8 0 250 1690 348 2013-04-23T22:39:01Z Admin 0 wikitext text/x-wiki [[Image:GFavalora.jpg]] Gregg E. Favalora (Arlington, Mass., USA) *B.S., Yale Univ. (1996) *S.M., Harvard Univ. (1998) *Founder and CTO, Actuality Systems (1997-present) *[http://www.actuality-systems.com Actuality Systems, Inc.] *[http://www.greggandjenny.com/gregg Personal homepage] Gregg Favalora is not a holographer in the traditional sense. Rather, he has focused on the design and development of many three-dimensional display architectures since being bitten by the "3-D bug" in 1988. He holds a BSEE from Yale and a Masters' in Engineering Sciences from Harvard, which he left in 1997 to found Actuality Systems, a firm specializing in 3-D visualization for medical imaging, oil & gas, and entertainment. His research interests include optics, 3-D displays and electro-holography, biologically-inspired electronic systems design and "neuromorphic engineering", and industrial design. In his spare time he wishes he were better at playing the drums and the ancient strategy game of go. In 1996, while a student at Yale, Gregg developed the first parallel raster-scanned 3-D display under the guidance of Prof. Peter Kindlmann. It used 32 laser diodes in conjunction with a polygonal mirror scanner to illuminate a rotating diffuse screen with 32,768 voxels. The autostereoscopic, full-parallax volumetric image occupied roughly egg-sized volume. It is described in U.S. Pat. 5,936,767 and has been in operation - through at least 2006 - in Becton Center at Yale University since 1996. In 1997, Gregg founded Actuality Systems to develop software and opto-electronic systems for true 3-D visualization. In 2001, Actuality's engineers developed the world's highest-resolution volumetric 3-D display. Now marketed under the name Perspecta(r), it generates 10"-diameter 3-D imagery by projecting patterned light at 6,000 frame/s onto a swiftly rotating diffuse screen. The imagery created by Perspecta is composed of approximately 100 million voxels. Through 2006, Actuality's innovations include: "Spatial Visualization Environment," the world's first software platform that interprets graphical data from standard applications and processes them for displays of a wide variety of underlying physics, such as multiplanar displays, holographic displays, and highly-multiview displays. With a team including Oliver S. Cossairt, Rick K. Dorval, and Sam Hill, showed that it is possible to create a volumetric display with voxels having viewer-position-dependent effects, such as variable opacity. Developed several quasi-holographic "aerial" display systems that project free-floating imagery measuring 1" x 1" x 1" to 6" x 6" x 3". Working with leading hospitals to use volumetric 3-D displays for the review of cancer therapy plans using radiation oncology. Gregg is an inventor or co-inventor on: *U.S. Pat. 5,936,767, "Multiplanar autostereoscopic imaging system" *U.S. Pat. 6,183,088, "Three-dimensional display system" *U.S. Pat. 6,487,020, "Volumetric three-dimensional display architecture" *U.S. Pat. 6,512,498, "Volumetric stroboscopic display" *U.S. Pat. 6,570,681, "System and method for dynamic optical switching" *U.S. Pat. 6,940,653, "Radiation conditioning system" Gregg is a winner of the 1996 National Inventors' Hall of Fame / BFGoodrich Collegiate Inventors Award, is a member of the MIT Technology Review "TR-100" young innovators, and is a frequent speaker on the topic of entrepreneurship. Due in large part to the efforts of Actuality's engineers, his work has appeared in the Wall Street Journal, Wired, CNN Headline News, and a variety of major technology and medical publications around the world. [[Category:People]] 534c6877d6f85b33b0a310bd687bc150c2d2ddbc 0 398 1732 948 2013-04-23T22:39:37Z Admin 0 wikitext text/x-wiki [[Image:Jross.jpg]] JONATHAN ROSS [http://www.jrholocollection.com WebSite] CURRICULUM VITAE BORN 1953 London EDUCATED Bryanston School, Dorset 1970 - 71 Studied Art History in Venice and London 1972 - 77 Worked as assistant in Film Production and Theatre Management 1978 - 79 Founded and managed The Hologram Place - The first European gallery devoted to holography 1978 - 90 Founded and managed SEE 3 (HOLOGRAMS) LTD. - a production company for the manufacture of display holograms 1992 Organised “Four British Holographers” exhibition at Smith’s Gallery Covent Garden 1993 Organised “Landscapes & Metamorphoses” exhibition at Smith’s Gallery 1994 Organised “3x8+1” a selection of holograms from personal collection at Milton Gallery, St.Paul’s School, London 1995 Contributed selection of holograms to “Holograms from around the World” James Dun’s House (Aberdeen Art Gallery) Guest curator of “The Art of Holography” at the National Museum of Photography, Film & Television, Bradford 1996 Co-curator of “Raum in Sicht - Magie in 3-D”, Technorama Switzerland. Special Consultant to Art in Holography2 Symposium, Nottingham University Exhibited selection from collection and gave paper on collecting holograms. 1997 Exhibited selection from collection at The Royal Photographic Society, Bath. 1998 Founded Gallery 286 in Earl’s Court Road, London and has curated an ongoing programme of exhibitions featuring holographers, photographers, painters and sculptors. Over 50 exhibitions to date, including one-person shows by John Kaufman, Andrew Pepper, Margaret Benyon, Matthew Schreiber, Jon Mitton and Pearl John 1999 Advisor to the Shearwater Foundation Holography Award Programme 2000 A special Exhibition of work selected from the collection at The Butler Institute of American Art, Youngstown, Ohio, USA The Royal Photographic Society Holography Group Summer Exhibition 2000. A selection of work from the Jonathan Ross Collection. 2004 Received The Royal Photographic Society Saxby Medal for contributions to 3-D Image-making 1988 - 93 Consultant Editor, Art Line International Art News 1983 - Hon.Treasurer, Royal Photographic Society Holography Group During his long association with holography, Jonathan Ross has assembled one of the world's most extensive collections of holograms, details of which can be found at http://www.jrholocollection.com [[Category:People]] 385f330640a6ef41f1cb79d26c57704779834f7e 0 404 1738 960 2013-04-23T22:39:54Z Admin 0 wikitext text/x-wiki [[Image:KBazargan.jpg]] Optics has interested me ever since I was a small child. Everything from how a movie was projected in a cinema, to why shadows were sometimes sharp and sometimes not, constantly occupied my mind. This inquisitiveness finally led to a masters degree in Optics, at Imperial College, London. Here I developed an interest in holography, so I stayed on to complete a PhD in Display Holography. I have uploaded the thesis [http://www.focalimage.com/public/kaveh-PhD.pdf here]. The two areas I worked on most were natural color holography, and dispersion compensation. For colour holography I proposed using the three "prime" colors (as first identified by W A Thornton in 1971) for image recording. The work on dispersion compensation led to a compact hologram viewer which was patented, and is now marketed as the [http://www.apple.com/science/profiles/voxel/ "VoxBox"]. After 5 years of research in holography I was distracted by the fascinating emergence of "desktop publishing", and set up a graphics and typesetting [http://www.river-valley.com company] in 1988, which is now established and pays the bills. I am now raising my head again in holography and hope to continue where I left off. [http://www.holographer.org The Holographer] represents my re-entry into the field. [[Category:People]] b8b6d563e9701d2f02a49ba7b807f96566654a9b 0 423 1746 997 2013-04-23T22:40:19Z Admin 0 wikitext text/x-wiki == Lon Moore == Lon Moore was one of the first holographers to mass produce reflection holograms of popularized imagery. During the 1970s and 80s, he succeeded in experimenting with different processing techniques, controlling the available colors produced by the predominantly monochromatic medium and using his chemical palette appropriately in each of his holograms. Moore was a director and instructor of the San Francisco School of Holography and has exhibited his work at numerous venues in the US and Canada. [[Category:People]] eb42a688a9d0612a0609cbe8e7ea6748f93f8204 0 435 1760 1021 2013-04-23T22:40:42Z Admin 0 wikitext text/x-wiki [[Image:MichaelHDag.jpg]] Born in Houston, TX in 1966 I became enamored with holography in 1984 soon after seeing the first National Geographic with a hologram of an Eagle on the cover. Up to that point I'd never asked for much beyond the typical geek-oriented holiday and birthday gifts such as telescopes, microscopes, circuit kits and the like but that summer I bought the Holography Handbook and soon after asked my parents for a laser. My mother liked to tell the story that after I asked for a laser she called up my father and said "he finally asked for something. He wants a laser." Unlike all her other kids I didn't ask for a car (I was 18 by this time) but asked for something right out of left field as far as they knew. My dad scrouged a .5mW laser out of a telecopier and I set about building a 4'x4' sand table in my bedroom. I made a few transmission holograms over the next year but nothing wonderful. I did end up cracking the foundation though. Fortunately my parents were forgiving. Since diving back into holography in 2003 I've made hundreds of holograms, some not worth keeping but I keep most anyway and have made many more worth keeping, selling, giving away to friends and associates as well as hanging on my walls. I enjoy sharing what I know in person, on the Holography Forum, through the PCG and tutorials on my web site. The full body of my work is available on my web site at [http://holography.dragonseye.com Dragon's Eye Holography] [[Category:People]] 8b19630ec94bd468d8f7d11d44f48e652e6bbf3d 0 432 1754 1015 2013-04-23T22:41:03Z Admin 0 wikitext text/x-wiki [http://www.mbenyon.com Margaret Benyon's Website] [[Image:Mbenyon.gif]] Initially a painter, Margaret Benyon began to make holograms in 1968 when holography was available only to scientists. Her aim was to take holography out of the science lab, and to enlarge the boundaries of what was traditionally seen as fine art. Her early body of work with holography was an exploration of those aspects that were unique to it. Living in Australia with her partner and two small children in the 1970's led to work that was more humanist and cross-cultural. On returning to the UK in 1980 she began to use the human body exclusively, in a personal, partly therapeutic way. More recently she has been exploring the naturalisation of holography, and the female aesthetic. Her work with creative holography has been recognised with academic fellowships, artists' residencies, and a number of other art and holography related awards. She is currently listed in the International Who's Who, and in the millenium year she was awarded an MBE by HM the Queen in the New Year Honours List 2000 for services to art. Her work has been seen in a large number of exhibitions, in countries as far apart as the USA, Canada, Portugal, Italy, Australia, France, Germany, Japan, and China. Her works are in a number of public collections, including the Australian National Gallery and the Victoria and Albert Museum, London, and in an undocumented number of private collections world-wide. In 1994 she received a Ph.D. from the Royal College of Art, London, for her research and activities in art holography. Margaret Benyon made most of her holograms in her home studio on the south coast of England for 23 years. This was a basic, low-tech, non-commercial holographic studio, one of very few in existence. However, she also used more sophisticated international labs, and in 2005 moved to Sydney, Australia. She is currently an honorary Professorial Visiting Fellow at the College of Fine Art at the University of New South Wales, and continues to work internationally from Australia. [[Category:People]] bf32f4c06b2318b30a7cae8a636054737681f456 0 424 1748 999 2013-04-23T22:41:17Z Admin 0 wikitext text/x-wiki [[Image:Lcross.jpg]] [[Category:People]] da2eee2ad1422d7fbba7f253ea4ff423d4418e96 0 399 1734 950 2013-04-23T22:41:33Z Admin 0 wikitext text/x-wiki [[Category:People]] 77f3967bfd415c1f7e93a4c290d247350ea0775c 0 258 1698 364 2013-04-23T22:41:53Z Admin 0 wikitext text/x-wiki == Hart Perry == During the last 30 years working as a filmmaker, Hart Perry has carved out three distinct reputations: social and music documentarian, cameraman and artist. In 1969 he was the youngest cameraman at the legendary Woodstock music festival and in 1970 he directed his first music video, "Alice Cooper." In 1977, he was the principal cinematographer of the award-winning documentary "Harlan County, U.S.A." During the 1970s and 1980s, Perry was a innovative force in the development of holographic movies (Integral holographic stereograms). Working with a grant from the National Endowment for the Arts in 1977, he built the second optical printer for producing holographic movies in the world. As President of the Holographic Film Company (New York), he worked on commercial applications for holographic movies in the areas of advertising and portraiture. In addition, he was the Director of the Cabin Creek Center's Artist-in-Residence program, funded by the National Endowment for the Arts and the New York State Council on the Arts. This program represented the innovative collaborations of holographies with visual artists, sculptors and dancers. In creating holographic movies, Mr. Perry converted 16mm film footage to holographic film to capture both motion and dimension. The holographic film was then wrapped inside a Plexiglas cylinder and illuminated for viewing with a normal light bulb. This process was invented by Lloyd Cross in 1972. His holograms of computer generated images produced in the early 70s were innovative and have been widely exhibited in museums and art galleries. In addition, he produced holograms for Salvador Dali, Milton Glazer, Mabou Mimes, Agam and other artists. [http://www.perryfilms.com/hart.html] [[Category:People]] d94f1ddab170b0b51442a6d67500d95064e9497f 0 255 1696 358 2013-04-23T22:42:07Z Admin 0 wikitext text/x-wiki [[Image:HBjelkhagen.jpg]] Dr Hans I. Bjelkhagen, professor of Interferential Imaging Sciences, with North East Institute for Higher Education, Wrexham, at the Centre for Modern Optics located in OpTIC Technium in North Wales, UK. He received his PhD degree in 1978 from the Royal Institute of Technology in Stockholm, Sweden. There he developed methods for recording interferometric holograms and performed holographic nondestructive testing for the Swedish car and airplane industry, e.g., VOLVO and SAAB. In addition to industrial applications of holography, Dr Bjelkhagen specialised in medical and dental holographic recordings. Dr Bjelkhagen has developed a holographic recording system for dental casts. The equipment: HOLODENT SYSTEM was produced and marketed by Dentatus International AB in Sweden. He has also invented and patented a special method to detect caries lesions (tooth decay) at an early stage based on laser fluorescence. Currently, a quantitative clinical system based on that patent is being developed and marketed by INSPEKTOR Research Systems bv in Amsterdam, the Netherlands. In 1983, he joined CERN in Geneva, Switzerland, where he was involved in development of bubble chamber holography. A year later he participated in an international team working on neutrino physics experiments recording holograms in the 15-foot bubble chamber at Fermilab in Batavia, IL, USA. Between 1985-1991 he was at Northwestern University, Evanston, IL, working on medical endoscopic applications of holography. He developed methods of recording in-vivo holograms at the tip of a special fibre-optic endoscope. Dr Bjelkhagen has been involved in the development of a large autostereoscopic computer display system when working for American Propylaea Corporation and Intrepid World Communications in Michigan. The project was carried out between Propylaea and US Army Tank Command, Warren, MI, through a CRDA (A Cooperative Research and Development Agreement). The work resulted in a prototype based on a 30" by 50" projection HOE and an array of single-lens video projectors and run by Silicon Graphics ONYX computers. During the last ten years, Dr Bjelkhagen has been most recognized for his work in colour holography, holographic recording materials and Lippmann photography. Dr Bjelkhagen has been able to demonstrate that high-quality full-colour holograms recorded in "white" laser light (combined RGB light from three laser wavelengths) could be stored in a single-layer ultra-high-resolution silver halide emulsion. In December 1997 Dr Bjelkhagen was invited by Professor Nicholas Phillips to join him at the newly established Centre for Modern Optics at De Montfort University, Leicester, in England. There he continued his research on 3D imaging, colour holography, colour HOEs, holographic recording materials, and Lippmann photography. Currently, a new optical variable device (OVD) based on the one-hundred-year-old Lippmann photographic colour recording technique is being developed. The application is in the field of optical document security. Individually recorded OVDs, similar to reflection holograms, can be applied to documents, such as, passports, ID-cards, driver’s licenses, etc. At the Centre for Modern Optics he has been involved in projects supported by companies, such as, SAMSUNG and SHARP. In addition to his scientific 3D coherent imaging Dr Bjelkhagen is a well-known holographer who has recorded many holograms for 3D display purposes. From his early years in holography he has been involved in large-format, high-quality display holography both pulsed and cw laser holography. He has recorded many unique art objects, such as, e.g., the Swedish Coronation Crown of Erik XIV (from 1561) in 1974 and the Chinese Flying Horse from Kansu (from 100 A.D.) at an exhibition in Stockholm in 1976. Dr Bjelkhagen has been working with several famous artists, for example, Carl Fredrik Reuterswärd, creating holograms exhibited in many art museums and art galleries around the world. Dr Bjelkhagen has specialized in pulsed display holograms, in particular, holographic portraits. He has recorded holograms of many people the most famous one being President Ronald Reagan, a portrait recorded May 24, 1991. This is the first and, so far, the only holographic portrait recorded of an American president. One copy of the holographic portrait is in The National Portrait Gallery of the Smithsonian Institution in Washington DC. When Dr Bjelkhagen was working in the USA in the 80s and 90s, he started two holographic companies together with two of his colleagues in Chicago. One company was HOLICON Corporation, a company specialised in large-format pulsed holography and portraiture. Among the interesting projects can be mentioned a promotional project for Bristol-Myers Squibb Company: "The Gallery of the Pathogenesis of Atherosclerosis" using hologram of microscopes through which arteries could be studied. After the campaign was over, the holograms were donated by Bristol-Myers Squibb to museums in the USA, for example, the Museum of Science and Industry in Chicago, where the holograms are still on display. HOLICON was also financially responsible and provided equipment for recording the 1991 holographic portrait of President Ronald Reagan which took place at Brooks Institute of Photography in Santa Barbara in California. The other company, Holographic Industries Inc., operated several Lightwave Hologram Galleries, marketing holograms and other holography-related products and located in US cities such as, e.g., Chicago, Detroit, and San Francisco. Dr Bjelkhagen has published over 100 papers in refereed journals and conference proceedings and holds 9 international patents. However, his most important academic contribution is the Springer book on Silver-Halide Recording Materials for Holography and Their Processing. That book considered to be the standard textbook on the subject is now used in many of the universities teaching holography as well as in most worldwide companies producing display holograms. Bjelkhagen is a member of the Optical Society of America (OSA) and a Topical Editor of the society's journal Applied Optics. He is a fellow the International Society for Optical Engineering (SPIE) and the co-chairman of SPIE's Holography Technical Group. He is an Accredited Senior Imaging Scientist and Fellow of The Royal Photographic Society (RPS). Bjelkhagen received the RPS SAXBY AWARD in 2001 for his work in holography. *2004 - present Professor, Interferential Imaging Sciences North East Institute of Higher Education, Wrexham, and Centre for Modern Optics at OpTIC Technium, St. Asaph, Wales *2001 -2004 Professor, Interferential Imaging Sciences, De Montfort University, Leicester, England. *1997 - 2001 Senior Research Fellow, Modern Optics De Montfort University, Leicester, England. *1996 - 1997, Visiting Research Scientist, Lake Forest College, Lake Forest, Illinois, USA. *1994 - 1995, Vice President - Research & Development, American Propylaea Corp., Birmingham, Michigan, USA. *1992 - 1994, Visiting Professor, University of Münster, Germany. *1985 – 1992, Associate Professor, Biomedical Engineering, Northwestern University, Evanston, Illinois, USA. *1985, 1991, Associate Professor, Applied Photonics, Louis Pasteur (6 months each University, Strasbourg, France. *1984 1985, Visiting Research Associate, Fermi National Accelerator Lab, Batavia, Illinois, USA. *1983 1984, Visiting Research Associate, CERN (European Organization for Nuclear Research), Geneva, Switzerland. *1978 1983, Associate Research Professor, Production Engineering, Royal Institute of Technology, Stockholm, Sweden. *1969 1978, Research Assistant, Production Engineering, Royal Institute of Technology, Stockholm, Sweden. Swedish citizen, UK resident, US Green Card Holder, Date of Birth: March 9, 1945, Stockholm, Sweden. [[Category:People]] 41b408f8a657e0c4a4d51715f0908719ff0bad2b 0 248 1686 344 2013-04-23T22:42:32Z Admin 0 wikitext text/x-wiki [http://www.hmt.com/holography/cherry/cherry.html Web Site] [[Category:People]] 36cdbb2c1a42716330d461c0d9439b683d336aa3 0 455 1762 1061 2013-04-23T22:42:54Z Admin 0 wikitext text/x-wiki [[Image:Pchristie.jpg]] [http://www.litiholographics.com Liti Holographics] Company founder, President and Chief Technology Officer Mr. Christie has extensive knowledge and experience in developing optical systems. Prior to completing graduate work in holographic & three-dimensional display technology at MIT, one of the world’s leading media labs, Mr. Christie was responsible for inventing several new technologies for improving LCD projection displays for Projectavision, Inc., one of which was patented. His Masters Degree work is also currently being patented by MIT. He subsequently formed the predecessor company to Liti Holographics in December of 1997. He holds a Bachelor's degree in Applied Physics from Columbia University and a Master's degree in Media Technology from MIT. [[Category:People]] fe344cdac626621a73c5104c6239430c2e28f398 0 458 1768 1067 2013-04-23T22:43:08Z Admin 0 wikitext text/x-wiki http://secure.netroedge.com/~phil/IRs/DSCN1472.jpg (high speed near-infrared photo from a digital camera (Nikon Coolpix 995) I modified just minutes before this photo was taken. I was staring in amazement at the LCD display while I snapped this picture. [http://holographyforum.org/phpBB2/viewtopic.php?t=2043 more on this]) I'm a scientist, engineer, and a wanna be entrepreneur. I was a Linux kernel developer for a while ([http://secure.netroedge.com/~lm78/ the project] still runs strong with the help of others), I have a degree in both computer science and computer engineering (the first is mostly software, the other hardware). I'm a weak lab sort. I'm impatient. For example, I hate movies, they take too long. So I spend a vast majority of my waking hours doing work on a computer (I prefer Linux for work, I support Macs at work, and have a few Windows machines for games and evil proprietary needs). I'm the IT, IS, DBA, telephone, sometimes backend web programmer, and general tech support guy at a small advertising/graphic design agency. As far as holography goes, I got amazed with holograms and lasers in middle and high school. At the time, though, it was expensive, very vague, and sometimes dangerous. Alas, I was completely unsuccessful at creating a hologram, and most likely I found out much later due to some useless Kodak film that was pushed on to me. My doubts lifted when I made a hologram in an unused bathroom at high school during electronics class (the closest thing to a hands-on science class at the time) using Agfa film (which at the time seemed to be getting very hard to get). Later, it was only after finding out about the Holography Forum that I got back into making, buying, and helping those making holograms (where I can) that I got back into the hobby. I'm proud to help Colin, Michael, John, and the many others who work hard to make holography less a monopoly, less scary, less mystical, and simply fun and creative. (PS- I have a problem with using too many parenthesis (as if you didn't notice!), but deal with it! This is my space! ;') [[http://www.holographyforum.org/HoloWiki/index.php?title=Talk:Phil_Edelbrock&action=edit Have a comment? Click here.]] [[Category:People]] f8aa3fa21d310c2223ed70395ddf03e5b1aadb32 0 456 1764 1063 2013-04-23T22:44:04Z Admin 0 wikitext text/x-wiki [[Image:Barefoot.jpg]] == ''Paul D. Barefoot'' == ''President:Holophile, Inc.'' Paul Barefoot saw his first hologram in New York at the International Center of Photography exhibition, ''Holography '75: The First Decade'', produced by Jody Burns and Posy Jackson. It was there that he caught "Holography Fever." Within months, he moved to New York from his hometown of Charlotte, NC, where he was Director of Marketing for a graphic arts company and a C130 pilot with the North Carolina National Guard. In November, 1975 he founded Holophile, Inc. to market holography to corporations and nonprofit clients. He also began an affiliation with John Bliss Associates, Inc. (later, Bliss, Barefoot & Associates, Inc.), who served as Public Relations counsel to the Museum of Holography from its inception in 1976. In 1977, Barefoot worked with Museum of Holography founder, Rosemary Jackson, to organize a traveling exhibition of the Museum's inaugural exhibition, ''Through the Looking Glass''. It opened in Toronto and traveled to art, science and children's museums throughout the U.S. Public response was overwhelmingly positive.The exhibition was booked with institutions continuously for ten years -- not returning to New York until its retirement in 1987. During that time, Barefoot took ''Looking Glass'' to Australia for an appearance at the Adelaide Festival of Arts, and to Jerusalem where it broke the all-time attendance record at the Israel Museum In1988, Barefoot began circulating the Museum's second traveling exhibition, ''FutureSight: Innovations in Art Holography''. This exhibition, curated by Rene Barilleaux, traveled to art museums and galleries in the U.S., plus a tour of four New Zealand museums in Auckland, Wellington, Christchurch and Dunedin. In 1992, Barefoot organized a new traveling exhibition entitled, ''The Nature of Holography''. A second show (of the same name) was developed in 1993 to meet the growing demand by art, science, and children's museums. A third exhibition, ''Holography: Making Faces'', was introduced in 2007. These exhibitions, which feature images from the Holophile Collection, are still in circulation. (See complete listing of host institutions since 1977 [http://www.holophile.com/html/exhibit.htm]) Since founding Holophile in 1975, Barefoot has worked as a producer of custom holograms for use by corporate, not-for-profit and government clients, including The American Gas Association, BP Oil de Venezuela S.A., Canary Islands Tourism Board, The Coca Cola Company, IBM, National Security Agency (NSA), M & T Chemicals, Inc., PricewaterhouseCoopers, Samsung Electronics, Pfizer Pharmaceuticals, Raytheon Canada, Ltd and The Weizmann Institute of Science. Barefoot continues to work in holography and other three-dimensional imaging technologies through his company, Holophile, Inc. ([http://www.holophile.com]), located in Killingworth, CT. [[Category:People]] ba43dbb773360f42110b9725d3185b157ad529f9 0 481 1790 1113 2013-04-23T22:44:31Z Admin 0 wikitext text/x-wiki [[Image:RLakes.jpg]] [[http://silver.neep.wisc.edu/~lakes/ Rod's Website]] *Columbia University, Mathematics, 1964, 1965 *Rensselaer Polytechnic Institute, B.S., 1969; Ph.D., 1975 *Yale University, Research Associate, 1975 -1977 Applications of holography: experimental mechanics Lakes, R. S., Gorman, D., and Bonfield, W., "Holographic screening method for microelastic solids", J. Materials Science, 20 2882-2888 (1985). Classical elastic and Cosserat elastic materials may be quickly distinguished via holographic study of displacement of a notch at the corner of a square section bar in torsion. Chen, C. P. and Lakes, R. S., "Holographic study of conventional and negative Poisson's ratio metallic foams: elasticity, yield, and micro-deformation", J. Materials Science, 26, 5397-5402 (1991). This article presents an experimental study by holographic interferometry of the following material properties of conventional and negative Poisson's ratio copper foams: Young's moduli, Poisson's ratios, yield strengths, and characteristic lengths associated with inhomogeneous deformation. The Young's modulus and yield strength of the conventional copper foam were comparable to those predicted by microstructural modelling on the basis of cellular rib bending. The re-entrant copper foam exhibited a negative Poisson's ratio as indicated by the elliptic contour fringes on the specimen surface in the bending tests. Inhomogeneous, non-affine deformation was observed holographically in both foam materials. Download pdf Lakes, R. S. and Elms, K., "Indentability of conventional and negative Poisson's ratio foams", J. Composite Materials, 27,1193-1202, (1993). The indentation resistance of foams, both of conventional structure and of a novel re-entrant structure giving rise to negative Poisson's ratio, was studied using holographic interferometry. In holographic indentation tests, re-entrant foams had higher yield strengths sigma y and lower stiffness E than conventional foams of the same original relative density. Damage in both kinds of foam occurred primarily directly under the indenter. Calculated energy absorption for dynamic impact is considerably higher for re-entrant foam than conventional foam. Chen, C. P. and Lakes, R. S., "Holographic study of non-affine deformation in copper foam with a negative Poisson's ratio -0.8", Scripta Metall et Mater., 29, 395-399, (1993). Negative Poisson's ratio copper foam (Poisson's ratio -0.8) with a permanent volumetric compression ratio of 2.2 exhibits a greater non-affine (inhomogeneous) deformation than either conventional foam or negative Poisson's ratio foam (Poisson's ratio = -0.1) with a volumetric compression ratio of 3. Anderson, W. B., Lakes, R. S., and Smith, M. C., "Holographic evaluation of warp in the torsion of a bar of cellular solid", Cellular Polymers, 14, 1-13, (1995). Holographic methods are utilized to examine deviations from classical elasticity in a cellular solid, polymethacrylamide closed cell foam. A square cross section bar is subjected to static torsional deformation. The warp deformation is observed to be less in a foam bar than in a homogeneous polymeric bar used as a control. The homogeneous bar obeys the predictions of classical elasticity. Behavior of the foam bar is consistent with Cosserat elasticity. In a Cosserat solid, points in the continuum to rotate as well as translate, and the material supports couple per unit area as well as force per unit area. Cosserat effects can lead to enhanced toughness. This image shows holographic fringes associated with warp. Development of holographic methods Lakes, R. S., "Multi wavelength techniques in holographic interferometry", Journal of Modern Optics, 35(9), 1459-1465 (1988). Techniques are presented which take advantage of the wavelength dependence of various phenomena in holographic interferometry. Image-plane interferograms illuminated with light containing multiple wavelengths exhibit color dispersion of the fringes. We extract from this dispersion, full- field information concerning displacement components which are not disclosed by monochromatic illumination. Cohen, B. and Lakes, R. S., "Aberration reduction in one step lens image plane holography", Applied Optics, 27, 3322-3323 (1988). A simple correction scheme is presented, which permits the use of large aperture lens systems of modest quality, even single element lenses, to produce image plane holograms viewable in white light. The present method allows white light reconstruction and corrects field curvature, which is the most objectionable aberration in display holograms. The field curvature was corrected by making the hologram with diverging light and illuminating the hologram with collimated light to introduce a compensating negative curvature of field. Wuest, D. and Lakes, R. S., "Color control in reflection holograms by humidity", Applied Optics, 30, 2363-2367 (1991). A method is presented which permits control of the reconstruction wavelength of reflection holograms and holographic optical elements [HOE's]. This approach makes use of developer and bleach which minimize emulsion shrinkage combined with control of ambient humidity to control the emulsion shrinkage during formation and reconstruction. A simple index matching approach to the elimination of the wood grain effect in reflection holograms is also presented. Applications: Holographic Optical Elements Wadle, S. and Lakes, R. S., "Holographic diffusers: polarization effects", Optical Engineering, 33, 1084-1088, (1994). In some applications of diffusers, it is desirable to minimize the diffuse back reflection of light. Use of polarized light is one way to reduce this back reflection. To that end, the effect of diffusers upon polarized light is studied experimentally. Diffusers based on ground glass, white plastic containing scatterers, and holographic optical elements are considered. The ground glass and HOE diffusers preserve polarization in the diffusion process, but the white plastic does not. Diffuse back reflection from ground glass or holographic diffusers can be significantly reduced by the use of an isolator based on a quarter wave plate. Wadle, S., Wuest, D., Cantalupo, J., and Lakes, R. S., "Holographic diffusers", Optical Engineering, 33, 213-218, (1994). Holographic diffusers were prepared using silver halide (Agfa 8E75 and Kodak 649F) and photopolymer (Polaroid DMP128 and DuPont 600, 705, and 150 series) media. It was possible to control the diffusion angle in three ways: by selection of the properties of the source diffuser, by control of its subtended angle, and by selection of the holographic medium. Several conventional diffusers based on refraction or scattering of light were examined for comparison. Wuest, D. and Lakes, R. S., "Holographic optical element for projection of stereo images", Applied Optics, 31, 1008-1009 (1992). We present a holographic element capable of projecting dynamic stereo images, and allowing the observer to see through the device, for possible use as a head up display in aircraft. The device is based on a volume reflection holographic optical element which contains two sets of Bragg planes. Each set of Bragg planes diffracts light from a two-dimensional source to the appropriate eye to achieve a stereo effect. Lakes, R. S. and Vick, G., "Partial collimation of light from a diffusely reflective source", J. Modern Optics, 39, 2113- 2119, (1992). A general purpose collimator capable of collimation of radiation from an arbitrary thermal source of diffuse light is incompatible with the second law of thermodynamics. However there are 'special purpose' collimators which would not be generally applicable. A new collimator which is effective when placed close to a white (diffusely reflective) source is presented. Wadle, S. and Lakes, R. S., "Holographic diffusers with low back-scatter", J. Modern Optics, 42, 1387-1396, (1995). Holographic diffusers have been produced with very low back diffusion in comparison with diffusion in the forward direction. Reduced back diffusion was achieved by lamination and index matching procedures which minimized the formation of Bragg planes parallel to the film surface. Photopolymer media were used as phase media. Diffusers with the lowest values of back diffusion were prepared by moderately restricting the field angle of incident light during formation. [[Category:People]] ddd99ba8306708afefb91413cc00ce19700d3029 0 493 1800 1137 2013-04-23T22:45:21Z Admin 0 wikitext text/x-wiki [[Image:SVorobyov.jpg]] A physicist, expert in holography, Ph. D. of technical sciences. Sergey Vorobyov has been studying holography since second year of the university. During 30 years of his work, he took part in the development of the main directions of applied holography - hologram manufacturing on silver-halide photomaterials, hologram production on dichromate gelatin, manufacturing of holograms for information systems, embossed and color holography and etc. Sergey Vorobyov was a member of the commission on industrial application of photoplates for holography: PFG-01, PFG-02, PFG-03, PFG-04 at the Slavich company. He took part in testing those plates and optimization of the manufacturing process. Sergey Vorobyov is director of holographic studio at the All-Russian Exhibition Center (Moscow). He developed unique technology of recording and copying of pulse holograms. Commercial manufacturing of display holograms has been organized with his help. Sergey constantly improves technology of manufacturing of transmission and reflection holograms. As a holography popularizer he wrote the course "25 holography lessons". It has been published in Russian and English on [http://www.holography.ru www.holography.ru] web site. Sergey Vorobyov also developed the compact kit for amateur holography. [[Category:People]] 32fb4eaddc7ce293998453e05f9c7d9c32976793 0 496 1804 1143 2013-04-23T22:45:32Z Admin 0 wikitext text/x-wiki [http://www.mccormackholography.com/ Sharon's Website] Sharon McCormack was born in New York City and now lives and works in the Columbia River Gorge National Scenic Area, White Salmon, Washington. Since 1975, Sharon's professional activities have included Owner/ Director, School of Holography, San Francisco, CA to holographic lens system construction for X-ray applications to lecturing, consulting, and commissioned work in the field of holography. Over that period, Sharon has created numerous world-wide group & solo exhibitions, has won many prestigious awards & grants, and has been featured in a broad range of publications from technical journals to sport magazines. [[Category:People]] 4933d12934abe1abcf5f1ffb462484e8925d3ee8 0 180 1606 208 2013-04-24T00:17:03Z Admin 0 wikitext text/x-wiki ==Must Haves== *Saxby, G., ''Practical Holography'' Third Edition, IOP, 2003, ISBN 0750309121. Reviews: [http://www.designerinlight.com/holo/graham.htm][http://www.dragonseye.com/blog/archives/17-Practical-Holography-3rd-Edition,-Graham-Saxby.html] *Unterseher, F., Hansen, J., Schlesing, B., ''Holography Handbook'', Ross Books, 1982, ISBN 0894960164. Reviews: [http://www.dragonseye.com/blog/archives/18-Holography-Handbook,-Unterseher,-et.-al.html] *Bjelkhagen, H., ''Silver Halide Recording Materials for Holography'', Springer-Verlag. 1996, ISBN 3540565760 *Hariharan, P., ''Optical Holography'', Cambridge University Press, 1996, ISBN 0521439655 *Keechner, W., ''Solid State Laser Engineering'', Springer, 1999, ISBN 3540650644 *DeFreitas, F., Rhody, A., Michael, S., ''Shoebox Holography'', Ross Books, 2000, ISBN 0894960601 ==Other Books== *Saleh, B., Teich, M., ''Fundamentals of Photonics'', John Wiley and Sons, 1991 *Jung, T. editor, ''Holographic Imaging and Materials'', Vol. 2043, SPIE, 1994 *Kock, W., ''Engineering Applications of Lasers and Holography'', Plenum Press, 1969 *Kasper, J., Feller, S., ''The Complete Book of Holograms'', John Wiley and Sons, 1987 *Cathey, W., ''Optical Information Processing and Holography'', John Wiley and Sons, 1974 *Brown, R., ''Lasers: Tools of Modern Technology'', Doubleday, 1968 *Jung, T. editor, ''Practical Holography II'', SPIE, 1987 *Iovine, J., ''Homemade Holograms'', Tab Books, 1990 *McGomb, G., ''The Laser Cookbook'', Tab Books, 1988 *Saxby, G., ''Holograms'', Focal Press, 1980 *Hecht, J., Teresi, D., ''Lasers: Light of a Million Uses'', Dover, 1998 *Horn, D., ''Laser Experimenters Handbook'', Tab Books, 1988 *Kock, W., ''Lasers and Holography'', Doubleday, 1981 *Ross, J., ''3x8+1'', Holograms 3-D, 1994 *Bergquist, C., ''Laser Design Toolkit'', Prompt Publications, 1999 *Smith, H., ''Principles of Holography'', Wiley, 1969 *Vacca, J., ''Holograms and Holography'', Charles River Media, 2001. Reviews: [http://www.dragonseye.com/blog/archives/19-Holograms-and-Holography-Vacca.html] *Gorglione, N. editor, ''The Archives of Holography'', Leonardo Vol. 25 No. 5, Pergamon Press, 1992 ==Holography Marketplace== *Ross, F., Yerkes, E., editors ''Holography Marketplace: Second Edition'', Ross Books, 1990 *Kluepfel, B., Ross, F., editors, ''Holography Marketplace: Third Edition'', Ross Books, 1991 *Kluepfel, B., Ross, F., editors, ''Holography Marketplace: Fourth Edition'', Ross Books, 1993 *Kluepfel, B., Rhody, A., Ross, F., editors, ''Holography Marketplace: Fifth Edition'', Ross Books, 1995 *Rhody, A., Ross, F., editors, ''Holography Marketplace: Sixth Edition'', Ross Books, 1997 *Rhody, A., Ross, F., editors, ''Holography Marketplace: Seventh Edition'', Ross Books, 1998 *Rhody, A., Ross, F., editors, ''Holography Marketplace: Eighth Edition'', Ross Books, 1999 ==Optics Books== *Popular Optics [[Popular Optics Review]] *Facets of Light [[Facets of Light Review]] *Seeing Light [[Seeing Light Review]] *Light Science [[Light Science Review]] f8e87b7564d5a4275dd1afd2c21a1e67d594f5eb 0 815 1618 2013-04-24T02:24:49Z Admin 0 wikitext text/x-wiki [[Category:Rallison]] == Materials == Available volume holographic recording materials include &lt;a href="http://web.archive.org/web/20080720014742/http://www.xmission.com/~ralcon/dcgprocess/index.html"&gt;DCG, SHG, PVA, assorted Photopolymers&lt;/a&gt;, and Kodak, Agfa and Ilford products. The DCG formulations include thicknesses from 4 to 50 microns, color control from 650 to 450 nm and &lt;a href="http://web.archive.org/web/20080720014742/http://www.xmission.com/~ralcon/phasemat.html#indexmod"&gt;index modulations&lt;/a&gt; up to .25 with a strong chirp and gradient. All other materials have properties that fall within the range of DCG formulations and are selected for sensitometric or environmental stability reasons as needed. Photo resist for surface diffraction has been added to make DOEs in glass, epoxy, and plastics. == Facilities == [[Image:Map.gif|right]]The development lab is a modest 8000 sq. feet and located in a remote corner of a high mountain valley in northern Utah. The solitude is convenient for long exposures in dichromated gelatin (DCG) or photo resist and the humidity is typically low. Salt Lake International Airport is little more than an hour away and skiing is close by.<br> == Ordering == As of 2004 all orders first have to be weighed as commercially viable or just an experiment and if there is a commercial potential the order will likely be handled by Wasatch Photonics http://www.wasatchphotonics.com/index.html&nbsp; I am now alone and can only do a few tasks in my own lab, which has been closed to all commercial activity by Cache County.&nbsp; We accept phone, fax, credit card and E-mail orders and will quote verbally for simple gratings and reflectors of up to about 20 square inches. More complex devices require drawings and written specs. Simple optics take 1 to 4 weeks, complex devices run 2 to 6 months. All orders are run in batches with a minimum cost of $500 for either masters or copies. Typical minimum deliverable batch results are three to six units. Costs for simple optics are strongly affected by tolerances, testing and finishing requirements. Costs for complex projects are affected additionally by design time, tooling, component purchases, masters sub-masters, transfers, &lt;a href="http://web.archive.org/web/20080720014742/http://www.xmission.com/~ralcon/hybrid96.html"&gt;wavelength compensations&lt;/a&gt;, diffraction limited performance, size and substrate materials. We can work on a cost plus fee or fixed price basis, some work may require that we do best effort only. Tooling and purchased parts may have to be paid for in advance. Terms are negotiable and normally net 30, but larger projects require incremental progress payments. For inquiries of any kind call or &lt;a href="http://web.archive.org/web/20080720014742/http://www.xmission.com/~ralcon/main.html#contact"&gt;contact&lt;/a&gt; the lab director == Contact Information == &lt;address&gt;Box 142<br> Paradise, Utah 84328-0142<br> Phone: 435-245-4623<br> FAX: 435-245-0507<br> Cell: 435-770-8480<br> Email: rdr@ralcon.com &lt;/address&gt; &lt;tbody&gt; &lt;/tbody&gt; {| border="1" cellpadding="10" |- ! Lab Director: ! Lab Technicians: |- valign="top" | &lt;a href="mailto:rdr@ralcon.com"&gt;Richard Rallison, PhD.&lt;/a&gt; | &lt;a href="mailto:robrallison@wasatchphotonics.com"&gt;Robert Rallison&lt;/a&gt;<br> |} <br> '''''Last modified on 1/14/01''''' <br> 75a710dd135a409d3253d93af3687fb849c0cc37 0 816 1620 2013-04-24T03:02:56Z Admin 0 /* APPLICATION NOTES */ wikitext text/x-wiki === ABSTRACT === We review the properties and relative usefulness of 3 non silver Volume holographic recording materials that are available today. Dichromated Gelatin (DCG) will receive the most attention followed by Dupont Omnidex products and a light treatment of Polyvinyl Carbazole (PVK). Enhancement and control of color, bandwidth and diffraction efficiency of volume reflection holograms recorded in DCG and photopolymers is discussed. Methods of increasing the bandwidth while shifting the center frequency toward the red is given for photopolymers. Red pseudo color will be covered thoroughly so that the practitioner will have all the elementary tools to make full color and broadband DCG holograms from scratch. The entire DCG technology is disclosed as it relates to production of high quality display holograms that span the spectrum and may be narrowband and very deep or shallow and broadband. === MATERIAL === The list of volume holographic recording materials includes the silver halide films, photopolymers, photocrosslinkers, photochromics, ferroelectric crystals and a few less well known oddities. While useful devices may be made in all these materials only a few will provide a holographer with a sufficiently high index modulation, resolution, signal to noise ratio, spectral response, and archival properties. The silver halide films have grain size limited resolution, scatter short wavelengths excessively, have only a moderate index modulation and tend to print out in UV light. They are popular for many applications because they can be made panchromatic, are much more sensitive than any other materials and are commercially available. We ocassionally use silver halide films to make master holograms and we reduce the blue scatter by converting them to a gelatin hologram (SHG). Used in this manner they are nearly equivalent to dichromated gelatin (DCG). They enable the production of DCG masters shot with red light at silver speeds that can be copied with green light in DCG and reconstructed finally at the original red color. SHG processes are covered in previous publications. The three materials detailed in this paper were chosen because they each have more or less all the properties needed for the construction of high quality or high efficiency broadband or narrowband color controlled holograms. They are not without faults however and the purpose of this work is to provide information to a holographer to assist him to make a better material choice for a particular task or to set up for production in DCG. Some information is given relating to the peculiar drop in average index in DCG, PVK and DMP128 due to the nature of the index modulation in these materials. Very thick coatings, up to about 50 microns are also dealt with in a special section. Comments made about preparation, processing, fine tuning, protection and applications are based on many years of working with DCG and many months of working with the other two materials, Dupont's Omnidex materials and Polyvinyl Carbazole (PVK). DMP 128 is another well documented material. It is a proprietary Polaroid formulation of lithium acrylate in combination with a branched polyethylenimine. Although it is not generally available commercially Polaroid has allowed laboratory evaluations and it is now quite common to get holograms mass produced in the material at Polaroid. Several other photopolymer systems are possibilities for holographic work but these 3 represent the readily available and practical recording materials of the day. === REFLECTION HOLOGRAM FABRICATION STEPS === ==== Mixing and coating ==== DCG is a mixture of Ammonium dichromate, gelatin and water. It is stirred together, heated, filtered and spun on or drawn down with a bar. Drying with or without heat from gel or liquid states makes little difference. Bright yellow lights are permissable. A 10 micron film can be made by mixing one gram dichromate with 3 grams of gelatin and 20 grams of water and spinning a flooded 8x10 glass plate at about 80 RPM. The solution and the coated plate is useful for about 3 days, much longer with refrigeration. PVK is dissolved in chlorobenzene along with Carbon tetraiodide, it is difficult to get into solution even with heat and agitation. It is also very unstable and may gel in as little as 15 minutes after mixing. The solution may be further thinned for convenient spinning but is easily applied with a bar. A number 28 bar will yield a 5 - 7 micron coating when 2 grams of PVK are dissolved in 25 grams of chlorobenzene. The patent disclosure mentions nothing about mixing the sensitizer with the PVK while still dry but if this is not done the solution will likely not be photosensitive. The solution will usually remain stable enough for coating for about 1 hour after mixing. The coated substrate is good for at least 8 hours. Dupont's materials can be purchased already to use on plastic substrates or may be obtained in liquid form for coating by any of the techniques covered here. ==== Storage after coating ==== DCG stores well at low humidity in a refrigerator or freezer but containers must prevent contamination, condensation, freezer burn and frost which can all destroy surface quality. Film of 10 to 20 microns or more store best and are good for at least a year. At room temperature and 50% RH, thin films are good for a few hours, thick films typically last a week or more. The addition of a small quantity of TMG to the mixture will greatly increase storage time at room temperature by increasing the PH. PVK does not store well as a rule, sometimes it has lasted a week in the refrigerator. Typically it moves suddenly to insensitivity within 24 hours and it does not seem to age gradually. The instabilities in coating and storing could be alleviated by adding more antioxidants to retard the spontaneous formation of free radicals but at the cost of reduced photo sensitivity. Dupont's materials seem to store well under refrigeration for a year or more depending on type, their newest film is also very sensitive, requiring only a few mj/cm*cm to expose in red or green. ==== Exposure characteristics ==== DCG is most sensitive in a hot moist environment. At 50% RH and 68 degrees F it may require 60 mj/cm*cm of 488 nm light, while at 75% RH and 80 F 4mj/cm will do the same job. At 441 nm less than 1 mj is enough and at 514 or 532, 50 to 100 may be necessary. The percentage of dichromate affects speed more or less linearly, a 25% mixture is typical but mixtures of from 10 to 30 percent are necessary to control color. Gross overexposure will cause a decrease in efficiency all the way to zero. Overexposure causes an initial increase then a decrease in bandwidth and a blue shift plus a compression of contrast or dynamic range. PVK is totally insensitive to moisture, water can be used as an index matching fluid with no effect on the hologram. It requires about 20 mj/cm*cm at 488 nm to make a good single beam reflection hologram and because it is a cross linker it can be overexposed. Over exposure also results in a blue shift, a wider, then narrower bandwidth and loss of contrast. The Dupont material is a real time material and as a result can interfere with itself during an exposure. As the hologram is forming it is also reconstructing and making small dimensional changes. The results can be that at some time during an exposure the reconstruction could be out of phase with the construction momentarily. The energy required varies from about 8 mj/cm*cm to a 100 or so mj. It has good resistance to water and readable holograms have been made by us in 100ms. ==== Processing procedures ==== DCG is hardened briefly in Kodak Fixer with hardener then rinsed and plunged into several hot or cool alcohol baths. Cool baths produce better uniformity and lower noise, hot baths can yield tremendous index modulations with large chirps in Bragg spacing but often with increased noise. Depending on the mixtures, temperatures and times spent in each bath, a wide range of effects can be had. Processing and reprocessing affects bandwidth and center frequency over 100 nm or more and index modulation can be varied from near nothing to .25. If the first pass in the baths produces a shift to red, a second pass can shift it to blue and a 100 nm bandwidth can be reprocessed to yield a 30 nm bandwidth. Typically "master" holograms are processed to construct near the recording wavelength but processing and dichromate content allow the control of color to range from 650 to 450 nm for a straight on exposure at 488 nm. This much versatility in color control is certainly useful and will be covered in more detail. Conformal mirrors on flat substrates can be color shifted easily with angle but more complex shapes must be tuned with processing and film formula juggling. As an example of a reprocessing procedure, a red shifted broadband mirror may be narrowed and blue shifted by agitation for 30 seconds in a room temp 50:50 mixture of water and alcohol then plunged into 99% hot alcohol with agitation for 30 seconds and pulled slowly from the hot bath. The direction of the shift can be controlled by the ratio of alcohol and water in the first bath and the amount of shift can be controlled by the time in the same bath. A near ideal tuning bath has a specific gravity of .86 when it is warmed to about 55 degrees C. This process can be repeated many times if necessary, especially if the last hot bath is not hot enough to cause excessive scattering center buildup. Multiple buffer baths between the first color control bath and the last dehydration bath help to keep the last bath clean. PVK is swollen in Xylene or Toluene for a few seconds then dried in warm Hexanes or Hexanes mixed with alcohols. Like DCG the latent image must be enhanced by swelling in the first solvent and then replacing that solvent with a miscible but nonswelling solvent. Again, color and modulation control is by temperature and time. Color control is similar to DCG methods and either broadband red shifts or narrowband blue shifts are possible by altering time and temperature. Reprocessing is possible but scattering centers build up rather quickly in this material. The first solvent probably dissolves away material as it causes swelling. Signal to noise is usually good in narrow band processing but not so good for broadband reconstructions. A recent proprietary improvement in processing involves the use of a clever monobath made up of two miscible solvents. One of the solvents will swell the PVK and is more volatile than the other solvent which will not soften or swell the PVK. The most volatile solvent evaporates first and leaves the hologram structure in rigid uniform shape while the second solvent is driven out with warm dry air. Dupont films are developed with UV light and heat. They may then be brightened and color shifted by the addition of monomers and or solvents. It is common practice to laminate a cover glass over gelatin holograms to protect them from moisture, abrasion and chemicals. Many common epoxies have been identified as safe for this purpose as well as a broad class of adhesives described as UV polymerizable substances,( monomers, epoxies, resins, adhesives, etc). I accidentally caused an enhancement of several photopolymer holograms while attempting to laminate them. In one case the bandwidth widened from 40 nm to 150 nm and the optical density remained almost as high as the original structure. The photopolymers behave a little like sponges that can be dampened and swollen or alternatively soaked and saturated while the shock dried DCG and PVK structures are more like a stack of Ruffles potato chips that get damp, go limp and then collapse. Enhancement of Dupont photopolymer is the easiest and most reliable. The holograms produced from blue exposures originally playback blue but the enhanced holograms playback at a longer wavelength and are noticeably brighter. Solvents alone brighten and shift the reconstructions to the red but they are temporary treatments and not generally as effective as UV curable monomer type adhesives. A Dupont product is now available to make predictable shifts in playback color. They provide a monomer on a cover sheet that will diffuse into the exposed film where it causes swelling and can then be fixed by polymerization under a UV source. Some Dupont film reflection holograms will respond to the following recipe with a red shift and increase in total diffracted energy. Apply Lightweld 401 evenly and cover then wait for a color change and cure with strong UV source. If this substance is left uncured it may destroy the original structure. It is also anaerobic and therefore requires a cover to cure. ==== Protection ==== DCG is notoriously bad at remaining stable in normal environments. Moisture will cause the Bragg structure to collapse and the gelatin grabs moisture easily from the air right through most plastics and glue. This material usually requires lamination between glass with enough gelatin removed around the edges to form an "O" ring seal. Thick plastics, such as 30 mil mylar, will also work and certain fluorinated plastics such as "Aclar" in thin 5 mill layers are satisfactory provided that the edges have been cleared of gelatin before laminating. PVK needs protection from abrasion but it stands alone as the only holographic material we ever worked with that is completely waterproof. It requires only a 4 mil mylar laminate for adequate abrasion protection from the environment. Dupont's materials may be used as is or uncovered and rolled down onto a glass substrate. They need very little protection after being fully polymerized with UV light but a stiff flat backing helps with image distortion. Water can affect them temporarily but the structure is essentially humidity proof. === APPLICATION NOTES === DCG is easily the most versatile material, just about any kind of HOE or hologram can be made in it. Unfortunately it has poor environmental stability and must be well protected or it may not be intact when you need it. As long as glass or thick plastic is acceptable in the finished product DCG is the number one choice. With some difficulty it can be made panchromatic for full color work and under warm moist conditions it is a little more sensitive than the other two in the blue-green region. The SHG versions are much more sensitive and represent the only fast "non silver" medium useful for pulse holography applications. PVK is not so pleasant to work with as DCG but it goes onto plastic substrates easily, has a high delta n and needs only minimal protection. It should be very good for such things as eyewear, solar collection and other outdoor applications or anyplace where superb environmental stability is required. Dupont's materials come with an ever wider range of properties. They are durable and panchromatic but lack a little in dynamic range. The maximum available index modulation is lower than the other two materials and display holograms are typically less bright. Initially we tried to determine the index modulation of simple reflectors made in each material by fitting them to the simple one dimensional Kogelnick expression for diffraction efficiency (D.E.) of reflection volume holograms. {| border="1" |- ! colspan="2" | Kogelnick Expression |- | <math> DE = \tanh^2 \, {{\pi\Delta n T} \over {\lambda\sin\Theta}} </math> | Where *T = thickness of material in microns *λ = .5 microns (typical) *sin θ = 1 (for conformal mirror) |} This relationship seldom describes real reflection structures because it does not describe the effects of a gradient on the index modulation (delta n) or a chirp in the grating spacing (d). A gradient in delta n such as is caused by the absorption of light by the sensitizing dye results in a smooth broadening of the angular and spectral bandwidths and a smoothing of sideband peaks (when DE is held constant.) A chirp in the Bragg plane spacing also broadens the bandwidth though not so smoothly and the combination produces a highly asymmetric spectral bandwidth. The data and a description of the computer model is given in a previous publication. All three materials exhibit a useful range of index modulation and color control and each has found multiple commercial uses. The differences lie mainly in sensitometric characteristics, environmental stability and in the degree of difficulty to obtain or use. The balance of this paper will detail the use of DCG. We will try to give instructions that can be followed by anyone that is already familiar with more conventional holographic fabrication techniques and materials. Some details are left out for the sake of brevity but can be found elsewhere in the references or other literature. === SPIN COATING APPARATUS === A variable speed turntable capable of 50 to 100 RPM will coat films of gelatin or PVK from 4 to 50 microns on 8 x 10 inch glass or plastic substrates. Plates as small as 3 inch diameter or as large as 16 x 16 inches have also been successfully coated with this range and technique. The turntable should be equipped with a surface or arms that will mate to a removable tray that is one or two inches larger than the substrates being coated. We have used ordinary variable speed phonograph players with pie tins turned upside down and glued to the turntables and we have used Dayton variable speed gear motors with heavy duty arms attached. Both devices worked very well. Trays have been made up of stainless steel, plexiglass, polyethylene dishpans or modified from aluminum cake and pizza pans. The best trays have straight sides measuring 2 1/2 to 4 inches high and are fitted with 3 rubber posts inside and outside. The posts inside hold the substrate an inch or so off the bottom of the tray and the outside posts serve to level the tray during pouring of solutions and to center the tray during spinning. The spinning tray and substrate may generate useful turbulence that aids in drying and distributing the solution. Excess solution is caught in the tray and emptied between substrates then is easily soaked clean in hot water after a days activities. An important component that augments drying and uniformity is the blower-heater. It hangs off center and above the whirling tray. Turbulence and heat combine to make uniform coatings in about five minutes. We recommend the use of a variable temperature 600 watt blower such as might be found in the ceilings of some bathrooms. A little experimenting with angle and position will quickly determine the best place to hang this unit in your clean hood or bench area. Coat and examine uniformity by looking for local fringe patterns under a fluorescent lamp or better yet a fluorescent long wave black light. === BAR COATING APPARATUS === Lab coating bars are available from R.D. Specialty Co. in Webster N.Y. Ph (716)265-0220. A selection of bar types may be purchased for about $ 50.00. We have used bars of 3/8" diameter wound with # 24 wire as a standard but we have other windings and diameters on hand for special applications and recommend you do the same. These bars are also useful for applying strippable coatings for anti halo backings, and have been used for coating photopolymers and protective epoxy layers etc. Jigging for bar coating can be as simple as a clipboard with lint free paper placed under the substrate. A better jig is one that holds the plate above a trough that can catch run-off. The whole thing can be plexiglass which is particularly easy to get gelatin off of and it also preferentially over glass attracts dust particles. Bar or spin coating is done in a class 100 environment and is accomplished by pouring out a line of solution and pulling it down with a uniform pressure and velocity. A little practice will determine correct amount of solution, speed and pressure. The bar is not rotated as it is pulled and a new location or freshly cleaned and dried bar is used on each new substrate. Variations in thickness may be accomplished by changing wire size or viscosity or both. Precautions must be taken to keep the bars clean and undamaged. We place used bars in warm water and rinse and dry them before each use. A rack that holds them suspended above any surfaces is useful for storage, cleaning and serial use. It can be made from plastics or metals. Coated plates need to be placed in a level position where they can air dry in a few minutes. The coating jig should be nominally level. Cronar, (polyester) substrates are easily coated with these bars. Cronar is a Dupont product. One source is Farrest Chemical &amp; Supply, 680 Toland St., San Francisco, CA (415)8241400. It is available in sheets (C-42) or rolls (C-41) in a variety of sizes. Exposure of Cronar is done with a thick glass vacuum chuck or by humidifying the gelatin and rolling it against a clean glass plate. It is optically active and you may need to identify its neutral optical axis before exposure. Processing is best done by stretching it in a frame for dipping and agitation or by clipping it flush to a glass substrate fitted with a handle on one side. === FILM PREPARATION === Many factors need to be considered when mixing DCG for holographic film. ==== Jelly strength ==== The jelly strength, measured with the Bloom Gelometer, is an important consideration. The current gelatin being used by us for film production is either MCB brand (Mattheson, Coleman, and Bell Manufacturing Chemists, Norwood, OH 45212 # GX-45' OH 45212) # GX-45. Grayslake Type B USP XXIII Box 248 Grayslake,IL . 60030 Phone (312) 223-8141 Contact Bob Buscher. Both gelatins have bloom strengths from 215-235. Comparable with the jelly strength is the rated solubility of the gelatin, and the mode of manufacturing. (Acid or Alkaline processed.) These can each make a considerable difference in the quality for each lot. It is best to test every specific lot before final acceptance of a gelatin. Perhaps the best rating for gelatin to be used for DCG is the jelly strength-to-viscosity ratio. A ratio of at least 4 or 5 to 1 is considered good. Our current batch has a bloom of 232 grams, a viscosity of 42 mps and a ph of 5.1. ==== Heating ==== One important caution when preparing the DCG film mixture is the destabilization of the gelatin at high temperature. When heated for an excessive period of time, the film breaks up, causing what we term as film "pits" in the final emulsion. These "pits" have the appearance of small circles of various sizes and scatter themselves throughout the plate. When the film is processed, the final image has small voids where the "pits" were. So far, the length of the heating time and the peak temperature that cause this have not been determined. In the past, temperature and heating time causing this have fluctuated. But the safe method is to heat the film mixture at the shortest possible heating time to dissolve the gelatin content completely. 130 F to 150 F (60 C.) is usually a high enough temperature to dissolve without cooking. Gelatin "melts" around 40 to 45 C. The causes of film "pitting" are still unknown to us as well as what the "pits" really are. But their characteristics (and that of gelatin) can give us some ideas. It is important to take all known preventative measures for keeping them off the emulsion. Triple filtering helps and avoiding hot spots while mixing helps. We use a standard mag stir hot plate and glass flasks which are heated slowly while stirring or heated in a water bath, a microwave oven has also worked well using plastic bottles . Film "pitting", or destabilization, in the past, has seemed to be affected by the solubility of the gelatin. The higher the solubility, the less likely film "pits" occurred. The solubility, of course, is slightly affected by jelly strength and impurities. Literature within the gelatin film industry indicates temperature separation may occur, partly due to the polysaccharide content of the gelatin. There is one speculation of film pits which involves the crystallinity function in drying films. (And this is a function of film temperature.) The other theory for film "pits" is the presence of insoluble impurities (such as arsenic, grease, etc.) on the surface of the film. These substances probably conglomerate during mixing and heating to make larger hydrophobic areas on the glass. Surfactants would alleviate this but they aggravate adhesion problems as well. ==== Water ==== Use deionized water for the DCG film mixture. It eliminates certain salts which have produced inconsistencies in film behavior. Distilled water is also acceptable. Any water should be funnel filtered through a 5 micron or smaller filter and be free of oil, grease, and bacteria that thrive on gelatin. ==== Storage ==== Film mixtures may be stored in a refrigerator for a week or two and reheated in water or a microwave oven as needed. When stored longer the become less and less likely to flow when warmed. ==== Film codes ==== The film mixtures vary in dichromate and gelatin percentages. The variations depend on the specific use that a DCG film plate has. The film code currently used contains three numbers. The first being the gram-weight of the ammonium dichromate, the second being the gram-weight of the gelatin, and the third being the gram-weight (mls) of the water to be used in the film mixture. (Usually mixed in a 500 ml poly bottle.) The code for film used in broadband image holograms is 8-30-350. Thus, 8 grams dichromate, 30 grams gelatine, and 350 grams (mls) of water are mixed together. The mixture code for "red" holograms is 3-30-200. Most holographic optics are made in 10-30-250 to 8-30-150. Very thick coatings of 30 to 50 microns can be made using a 3-30-125 mixture but special fixturing may have to be made to get the gelatin to flow uniformly and the dried film may come off the substrate unless it is baked on at high humidity. We find adhesion is enhanced by cleaning the substrate in clorox and then baking the coated plate at 130 degree F in the presense of water at saturation. In using the film code for a variety of mixtures, the 30-gram gelatin weight number always remains constant. Thus, when a thicker emulsion is desired, the water number decreases. And when more absorption is desired, the dichromate number increases, an increase in thickness narrows the bandwidth and an increase in dichromate shifts the color toward the blue. As a general rule, thicker emulsions require longer process times but are easier to make uniform. The dichromate concentration determines light absorption and the center reconstruction wavelength of the hologram. For higher dichromate concentrations, the increased absorption produces larger gradients of index modulation. Lower the dichromate concentrations produce more uniform index modulations. Larger gradients yield slightly larger bandwidths and the removal of higher percentages of dichromate during processing results in thinner and thus bluer holograms. When a specific bandwidth is desired, along with a specific reconstruction wavelength; it is best to experiment with various film mixtures. Usually starting with a standard mixture and then adjusting the thickness, and dichromate content to achieve the desired results. The color controllability and uniformity of DCG film improves with thicker film emulsions. Consequently, they are more forgiving in their exposing and developing parameters. Extremely thick (25 micron or more) emulsions ( X-30-150, a 5 to 1 water-to-gel ratio) are difficult to use. They are prone to excess bubbles, pre-mature jelling, film pits, low viscous flow, increased impurities and during processing sometimes pull up off the substrate if not annealed in a wet oven. Processing of these thick films is often done with room temperature baths, or slightly elavated temperatures, over several minutes in each bath. ==== Sensitizer ==== We use ammonium dichromate crystals or for redder reds Potassium dichromate but the most sensitive of the dichromates is Pyridine dichromate. We don't use it because of it's shorter life and difficult preparation. The addition of ammonium nitrate can make the dichromate several times more sensitive, but decreases the useful life and blue shifts the image. Approximate ammonium nitrate concentrations are usually in a ratio of 1 to 5 by weight to ammonium dichromate up to a maximum of 1 to 1. When the additional substance is washed out of the gelatin a net shrinkage occurs which amounts to a blue shift in reflection holograms and lays down Bragg planes in transmission holograms. ==== Filtering ==== At a minimum, filter the heated mixture through two coffee filters (Mr. Coffee) for a standard 8-30-350 film. For 6-30-200 and thicker emulsions, use one coffee filter. Run the filtered mix into the pouring container. When necessary, a finer grade lab filter may be used, we have forced warm gelatin through a 1 micron filter using a gear pump and also using a peristaltic pump. The use of a peristaltic pump makes metering and filtering possible at the same time. A simple syringe with a 2 micron filter is very effective and may double as a way to meter out a fixed amount onto a plate. ==== Applicator ==== The pouring container (with the film) is kept on an electric warming plate. The temperature of the plate should be carefully controlled to provide only enough warmth to prevent jelling (50-60 degrees C). We like to use a lab hot plate and water bath, the pouring container is a tea pot like bottle modified from a lab wash bottle. Any poly bottle that empties from the bottom will do. Some custom shaping of the "spout" may be necessary to prevent the formation of bubbles. === COATING TECHNIQUES === The coating station consists of a class 100 cleanhood or laminar flow bench, a dryer-heater unit and the turntable. The clean hood should be large enough to fit the turntable and two plate racks inside. (About 2 1/2' x 3 1/2' or larger.) A yellow safelight may also be mounted inside. Air flow should be 200 cfm or higher for this size hood. ==== Cleaning glass ==== There is a bit of an art to coating and it takes a little practice to become good at it. The first step is to prepare the plates by soaking over night in a soapy solution that contains some chlorine. The plates also need scrubbing and a rinse in deionized water. The final rinse should be done in or in front of the clean hood used for drying the plates. The chlorine soak has been found to aid in adhesion of the gel to the glass. The glass may be soda lime plate or float glass or any most any other kind but it has to be thick enough to withstand the shrinking forces generated during exposure. This means that it should be double strength or thicker(3 to 6 mm) for 8 x 10 shots, single strength (2 to 3 mm) for 4 x 5 and 5 x 7, and may be picture glass or as thin as 1 mm for 2 x 2 exposures. ==== Coating glass ==== The gelatin is poured over the dried plate in such a way that no gel spills off the edge and no bubbles are formed. This is accomplished by pouring a large puddle and gently rocking the tray till all edges are wet. The turntable is then turned on with the blower/heater for about 5 minutes. If the plate was uniformly wet and had no contaminants then the coating is likely to be uniform using these techniques. The range of RPM we found useful runs from 65 to 100, speeds outside this range failed to be uniform. Start with a rotation speed of about 80 RPM and position the heater-blower about 6 inches above and to one side of center of the coating tray. For 8 by 10 plates this offset is about 3 inches. The fine tuning of the position of the blower will greatly improve the uniformity of your coatings. ==== Ageing and thickness ==== The film is ready for exposure after it has been aged an hour or so for a 350 mixture or a day later for a 150 mixture. The addition of 1 or 2 ml of TMG will extend the useful room temp life of 350 film to a day or two and will make 150 film last for several weeks in a 21 degree C, 50% RH environment. The thicknesses of the commonly used mixtures after spinning at 80 RPM and after processing are as follows: 350 yields 5-6 microns, 250 yields 8-9 microns, 200 yields 10-12 microns, 150 yields 20-24 microns and 125 yields 25 to 50 microns depending on speed. ==== Bandwidths and color ==== The relative bandwidths run from 50 to 150 nm for 350 film, depending on processing used. 250 and 200 film make 10 to 50 nm bandwidths depending on processing and 150 film can get down to 8 nm but also runs as high as 30 nm. Very thick film can have bandwidths of less than 8 nm. The color of a film made from a 3-30-200 mixture is around 630 nm when shot at 514 nm. The color of 6- 30 film is around 590 for a 514 shot and a 10-30 mixture will easily be tuned to play back at the same wavelength it was shot at. Methods of planning and controlling color in display holograms are discussed below, similar but more precise methods are used for HOEs. === COLOR DICHROMATE OBJECT PREPARATION === The two color method produces rich red-orange and bright clean blue-green colors that mix to a creamy white. Color coding of the object is optional but helpful in most cases and production is done from two masters in two different films. The three color system requires color coding for red at the mastering stage but no coding for blue or green, which are mastered first. Both systems are part natural, part pseudo color and require only two laser lines and two film formulations. Blue is obtained naturally by using the 458 argon line and green or red are derived from the 514 line. In production the two color system is identical to current master/copy methods in that batches are shot at 458 or at 514 and later registered and laminated together. The three color system requires blue and green exposures in the same emulsion and red in a second batch. The laser must then be operated multiline or be switched constantly or a second laser introduced. The preferred method is multiline operation with independent shuttering except that max power in each line is reduced because several lines compete for available energy. The two color, two plate system makes very satisfying flesh tones and color balance is fairly easy to maintain because it can be done by mixing and matching batches and or individual holograms at the laminating stage. The two color single plate method has the obvious advantage of no registration problems but it has a limited color range because there are only 56 nm between 458 and 514nm. ==== Object preparation ==== Blue-green areas should be overcoated lightly with a bright blue pigment such as Liquitex Brilliant Blue #20002-381 or Pelikan Deep Blue #39. This will effectively inhibit refection at 514. The red-orange areas must be touched up with yellow pigment such as Liquitex #1002-411 or Pelikan Yellow #10 both of which absorb 458 but reflect 514. At this stage H1 masters or correctly colored copies can be made, the Blue-Green master may be made to reconstruct at 488 so that production copies can be done using only 488 and 514. The 514 exposure is done with the film side facing the reference beam and the 458 exposure is done the other way around with a spacer between the object and film having the same optical thickness as the 514 substrate. ==== Film preparations ==== A good blue or green production film can be made by mixing the 8-30-250 formulae with or without a ml of TMG. A good red or yellow film is made by reducing the amount of dichromate to 2 or 3 grams. The plates are ready to use after standing at room temp for an hour and they may be stored in a refrigerator for months on end. Better results may be obtained from some softer gelatins by ageing films for a few days. ==== Exposure procedures ==== Blue holograms may be made by exposing in a Denisyuk fashion @ 458, 441, 476 nm or some other line bluer than 488. The energy required is about 20 mj/cm*cm and it helps to do it with the reference at 50 degrees from the normal and with the E vector perpendicular to the plate to reduce noise from mirroring. Green holograms may be similarly produced by using the 514 line, again near Brewster's angle. This time it may pay to try 55 degrees because absorption is much lower @ 514 so "Newton's wood" type noise is more likely to show up.The energy required is about 90 mj/cm*cm. Red holograms result from using the red film formula and exposing @ 514 close to Brewster's angle. The fringe structure is expanded to red or yellow reconstruction because less material is washed out during development. If the master has been made in SHG using a HeNe then this copy will be a correct color reproduction. ==== Processing procedures ==== The film of gelatin is about 8 or 9 microns thick and requires much longer processing times than 4 or 5 micron broadband films. Development takes 3 to 5 minutes in kodak fixer, followed by a 1 minute rinse in tap water. Dehydration is done in warm isopropyl alcohol (48 to 55 degrees C) using at least 2 baths after the tuning bath and agitating mildly in each for about 30 seconds. Drying is most easily done by removing the plate very slowly from the last and driest bath. If it does not look uniform try soaking in warm water for 10 minutes and then dehydrate with more agitation. Fine tuning of the color may be done by soaking in the tuning bath. This is the way that we get the center reconstruction frequency to match the copy wavelength. Start with a master that is a little too red and gradually tune it to the correct color by repeated passes through the tuning bath and the last hot dry bath. 350, 250, and even 200 mixtures all respond to this method. A hydrometer is necessary to monitor the specific gravity of the tuning bath and maintain it at or near .86. Processing 350 film for masters is done this way but the same film can be processed for broadband reconstruction by using a shorter development time and skipping the tuning bath. Experimenting is the only way to get the desired results. Some guides to broadband techniques can be found in the proceedings of the first Lake Forest symposium in 1982. An alternative to multiple bath processing has been proposed by workers at IBM. They suggest that for thin films, on the order of our 350 or 400 mixtures, spinning the plate while spraying a series of fluids works best. Thin films are not easy to process in baths because of the fast diffusion of solvents in and out of the rather porous gelatin. In the IBM method, all of the regular baths are sprayed progressively for only a few seconds each onto the spinning plate. They felt that the spray system would be a superior way to automate processing techniques, we experimented with spraying many years ago but did not have the success that IBM has had. === Hazards === Dichromate powder is dangerous if inhaled and the liquid mixture may irritate some people if left on the skin. Dust masks and rubber gloves are therefore recommended whenever film is being made. Isopropyl alcohol has low toxicity but is quite flammable and must always be heated in a safe manner such as in a water bath. Alcohol fires may be extinguished with water, dry chemical, Halon or CO2. Glass must be handled carefully and whenever possible the edges should be ground before handling. === REFERENCES === These references are all by the same author and may be useful to the holographer that tries to apply the methods detailed in this paper. A design guide and brochure for HOE's is available on request. A video tape demonstrating this technology is also conditionally available from the author. *"Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)." S.P.I.E. Proceedings, Volume 212, pp. 22, 1979 *"Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College Holography Workshop and First International Symposium on Display Holography, July 1982. Lake Forest, IL. *"Practical Polymers for Holography", Second International Symposium on Display Holography, Lake Forest College, IL. *"Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug. 1987. *"Alternative Volume Recording Media, A Qualitative Comparison" Third International Symposium on Display Holography, Lake Forest College, IL 1988 *"Survey of properties of volume holographic materials", SPIE vol. 1051, Practicle Holography III, 1989 p. 68 - LA, CA. *"Novel Enhancement of Photopolymers", SPIE vol 1212, Practical Holography IV, 1990 LA, CA. '''''Last modified on 4/8/99''''' [[Category:Rallison]] a8e0ff6aeed14c1429133bd88a02e11e75bea1f4 0 209 1638 266 2013-04-24T03:11:26Z Admin 0 wikitext text/x-wiki [[Image:DBattin.jpg|right]] [http://www.geocities.com/greenpagoda/islandholo1.html Dave's Web Site] It all started for me in the Museum of Holography, in the late 70s. after making one visit i was hooked for life! Seeing what could be done was unbeleivable..... I then joined as a member and started to read any information i could absorb. Attending college in Boston I found all kinds of new info at the college libaries. Upon graduation from college I headded west, finding work near Los Angles in a large machine shop, I found this very convenient for making tooling for my holographic components. After leaving LA and returning to New York, I continued my holographic studies, and met a fellow holographer, Mark Segal (owner of now defunct Spatial Images International)at this lab we produced a large ammout of DCG holography. A short time later a head hunter contacted me about a job working for company called Farirchild Weston Space and Camera, the job was for an optical engineer, I couldn't wait for the interview! They hired me in a flash! The optics lab was about 2500 sq.ft of total OPTICS! Lenses, mirrors, lasers a gigantic isolation table (20 tons+), I spent the next five years building telephoto lenses ths size of 55 gallon drums and tiny ccd cameras that would fit in matchbox! This is where I really learned about the nature of light and optics. [[Category:People]] dec7551dc88e663db92e6acadaa6de01915bb285 0 222 1668 292 2013-04-25T01:29:21Z Admin 0 wikitext text/x-wiki [[Image:Ed_Wesly.jpg]] Ed Wesly Ruby Pulsed Hologram - Fermilab PROFESSIONAL OBJECTIVE: To continue to share my wealth of knowledge and experience with more students in the fields of lasers, optics, holography and photography. TEACHING EXPERIENCE: Full-Time Faculty, Harrington College of Design, teaching Physics of Light (Optics), Photo-History, and College Math in the Digital Photography Department, January 2005 to present. Adjunct Assistant Professor, teaching a variety of classes in the Art and Technology and Liberal Arts Departments at the School of the Art Institute of Chicago, including the Beginning and Intermediate/Advanced Holography Studio, Optics for Artists, 3-D Hard Copy, and The Physics of Everyday Objects, January 1986 to present, with a couple of hiatuses. Instructor, Columbia College, Chicago, for the courses, "The Physics of Lasers, Holograms, and Modern Optics", "Photographic Theory/Laboratory Practice for Cinematographers", and "Imaging Optics", February 1985 to June 1997. Teacher, Cicero School, Cicero, IL, 7th and 8th grade Math Classes, September 1981 to June 1982. Director of Education for the Fine Arts Research and Holographic Center, Chicago, IL, June 1980 to May 1981. Teacher, Hardey Preparatory School, Chicago, 6th, 7th, and 8th grade Math Classes, September 1977 to June 1980. TECHNICAL EXPERIENCE: Production Holographer, CFC International, Countryside, IL, laboratory technician preparing holographic images for mass production, October 1998 to November 2004. Sales Engineer, BEA electro-optics, Des Plaines, IL, manufacturer's representative for a variety of electro-optical companies, June 1997 to October 1998. Research Associate at Lake Forest College, Lake Forest, IL, supported by a grant from a manufacturer of medical equipment to test the feasibility of replacing conventional optics in some of their equipment with Holographic Optical Elements, October 1987 to February 1993. Holographic Engineer for Northwestern University, Evanston, IL, researching holographic endoscopes using Ruby laser light piped through fiber optics, May 1986 to May 1987. Holographic Engineer for Holicon Corporation, Evanston, IL, setting up a studio to record holographic portraits using a Ruby laser, May 1986 to May 1987. Holographer for the 15 foot Bubble Chamber at Fermilab, Batavia, IL. Part of a team using a Ruby laser to make holograms of atomic particle tracks, March 1985 to April 1986. Optical Engineer for Magnaflux Corporation, Chicago, IL. Designed and built an 8 by 8 foot isolation table equipped with an Argon laser for real time interferometry of large objects, October 1983 to September 1984. EDUCATIONAL BACKGROUND: University of Illinois at Urbana, Bachelor's of Science Degree in the Teaching of Mathematics, January 1976. PROFESSIONAL ORGANIZATIONS: Member of the Optical Society of America, (OSA), and the Society of Photo-Instrumentation Engineers (SPIE). Councillor for Chicago Chapter of SPIE/Optical Society of Chicago Featured Speaker at the June, 1997 meeting of the Optical Society of Chicago. PUBLICATIONS TEXTBOOKS (self-published): INSTRUCTION MANUAL FOR THE HOLOGRAPHY STUDIO AT SAIC, September 1995 OPTICS FOR ARTISTS, September 1995 (e-version on-line Fall 2003) PHOTOGRAPHIC THEORY/LABORATORY PRACTICE For Cinematographers, September 1995 IMAGING OPTICS, February 1996 VIDEOS: "Ruby Laser Guts", 1996, and "Gaseous Lasers", 1996 SELECTED ARTICLES: "Inside-Out Engineering: Characterizing the Holographic Stereogram Printer at The School of the Art Institute of Chicago", Proceedings of the SPIE, 1997. "A Toast to Nick Phillips", Leonardo, Volume X, Number 3, 1992. "A Proposal for a National Space Monument", Proceedings of the SPIE, Vol. 1600, 1991. "Holography of Particle Tracks in the Fermilab 15-Foot Bubble Chamber," with W. Smart et al., Nuclear Instruments and Methods in Physics Research A297, 1990, p.364-389. "Teaching Holography in an Art School Environment," Proceedings of the SPIE, Vol. 1396, 1990. "Progress in True Color Holography", with T. Jeong, Proceedings of the SPIE, Vol. 1211, 1990. "Recycling Holographic Plates", Proceedings of the Third International Symposium on Display Holography, Lake Forest College, 1988. "Exploring Personal Holography", Darkroom and Creative Camera Techniques, Nov/Dec. 1986. "Seven Single Beam Projects", Proceedings of the Second International Symposium on Display Holography, Lake Forest College, 1985. Technical Editor for holosphere, the Advocate of Holographic Art, Science, and Technology, 1985 to 1991. REFERENCES: Dr. Tung Jeong, emeritus, Lake Forest College, Lake Forest, IL (Tjeong@aol.com) Dr. Hans Bjelkhagen, DeMontfort University, Leicester, England (Hansholo@aol.com) Dr. Manfred Stelter, PTI, Oak Creek, WI (pti@execpc.com) Dr. Gerald Cohn, Cyber-Tech, Evanston, IL (cybertek@megsinet.net) Dr. Elizabeth Wright, School of the Art Institute of Chicago, Chicago, IL (ewright@artic.edu) Dr. Pan Papacosta, Columbia College, Chicago, IL EXHIBITIONS: GROUP SHOWS Untitled, Richard Hunt Art Center, Benton Harbor Michigan, November 1996. Candy for the Eyes, Mind and Sol Gallery, Chicago, IL, September 1995. Unknown Chicago, Gallery 312, Chicago, IL, July 1995. The Fourth International Exhibition of Display Holography, Lake Forest College, July 1991. Matter Over Mind Sculpture Conference, Fermilab, Batavia, IL, May 1991. Diorama Wonderama, Gallery 836, Chicago, IL, November 1990. L.A.S.E.R. Members Show, Holos Gallery, San Francisco, CA, Summer 1990. New Media, New Directions, Northern Indiana Arts Association, Munster, IN, August, 1990. International Congress on Art in Holography, May - July 1990. The One-Liner Show, Gallery F-XU, Chicago, IL, February 1990. Visual Perceptions: Color, Light and Space, Gallery of Design of the Merchandise Mart, Chicago, IL, February 1989. The Third International Exhibition of Display Holography, Lake Forest College, July 1988. Visions in Light, Museum of Holography, Summer 1988. Images in Time and Space, Montreal, Canada, May 1987 to June 1989. The Holographic Instant: Pulse Laser Holograms, at the Museum of Holography, New York, May to October 1987. A.I.R. Waves at the Museum of Holography, New York, January to May 1987. 2 X 2 Show at the School of the Art Institute of Chicago, May 1986. Holography Group Show at the Limelight, Chicago, February 1986. Holography Exhibition at the School of the Art Institute of Chicago, November 1985. The Second International Exhibition of Display Holography, Lake Forest College, July 1985. New Light, Chicago Public Library Cultural Center, July 1984. The Connie Show, W.P.A. Gallery, Chicago, IL, April 1984. Stare Magazine Fifth Anniversary Show, at Word City, Chicago, June 1982. Post-Mortem Moderne, at the House o' Beauty, Chicago, IL, July 1980. First Contact, Chicago, IL, February, 1979. Illinois Photographers' Lottery, De Kalb, IL, May, 1978. EXHIBITIONS: ONE MAN SHOWS Down in the Basement, Artigliography, Indianapolis, IN, September - October, 1990. Doodles, Atlanta Gallery of Holography, Atlanta, GA, April 1990 Recent Pulsed Stuff and Other Delights at Benny's CASINO, Chicago IL, August 1986. AWARDS: Artist in Residence Direct Grant, from the Museum of Holography, New York, October 1984. Participant in the International Congress on Art in Holography, St. Mary's College, South Bend, IN, July 1990. COLLECTIONS: Global Images, Vancouver, British Columbia, Canada. Museum of Holography Collection, MIT Museum, Cambridge, MS. Dimensional Imaging Consultants, Niles, MI. Hans Bjelkhagen, Leicester, England [[Category:People]] d22df05f470265c9b1321e80eebbeee42a8a00e6 0 843 1776 2013-04-26T00:17:22Z Admin 0 Created page with "== Education == *Engineering Studies, Utah State University, 1964-1968 *B.S.E.E., University of Utah, 1969-1973 (Cum Laude) *M.S.E.E. Laser Systems, U.S.C. 1974-75 (not comple…" wikitext text/x-wiki == Education == *Engineering Studies, Utah State University, 1964-1968 *B.S.E.E., University of Utah, 1969-1973 (Cum Laude) *M.S.E.E. Laser Systems, U.S.C. 1974-75 (not completed) *Ph.D. Electro Optical Engineering, Honorary, USU 1995 == Experience and prior work == Approximately 35 years of professional or technical grade experience. Has been engaged in development work of CO2 Waveguide, Co-Axial Cadmium, Doubled "blue" Yag and Dye lasers at Hughes Aircraft for space communications, countermeasures and underwater communications. Performed ION laser design upgrades at American Laser Corp. and fabricated a novel multiple pass Ruby laser system for Dikrotek. Experienced with diode lasers including fabrication of a small bar code scanner for that coupled a diode laser, grin rod and focusing holographic scanner together. Another device developed and co patented with IBM splits diode laser light into polarized components and replaces a Wollaston prism. An early commercial success for IBM was the development of holographic scanner fabrication methods in 1979, followed by many years of development in Holographic elements, devices and systems and sales of Holographic Optical Element (HOE) fabrication technology to IBM, Pilkington (UK), Holosonics, Seimens, Raven Holographics in England, Portson Inc of Kansas., APA Optics of MN, Northrop corp of CA., Metrologic Instruments of NJ, Process Instruments of SLC, Bell Resources in Australia and Terabeam of Seattle. Work for NASA beginning in 1990 to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have begun. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s. Many spectrographic optical designs, head mounted display designs and some holographic memory designs have been made and brass-boarded. Some have become commercial products. Mr. Rallison has served as a consultant in Diffractive Optics for dozens of companies and has given numerous lectures on holography at the University of Utah, USU and Lake forest College as well as occasional invitations to give paid tutorials in industry. Other work includes the design and fabrication of novel HUD optics for the Air Force on an SBIR grant and an investigation of new holographic recording polymers for the Army NVL on an SBIR contracts. Contracts have been successfully completed for the army at Aberdeen where 5 HMDs were designed fabricated and delivered. Work for VIO in Seattle involved design and fabrication of Stereo Color HMDs or their components. 10 years of work on NASA contracts to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have been attempted. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s such as telecom receivers for free space interconnects developed for another Seattle company named Terabeam, co-founded by RD Rallison. He has fabricated multi lens arrays, gratings, HUDs, notch filters, Fourier filters, scanners, co-phasal multiplexed gratings, spectrophotometer gratings and filters, reflectors, diffusers, depixelators and assorted other HOEs. He owned and operated a company that produced millions of high quality display holograms for commercial use over a 10-year period. He worked as a Video Engineer and Cameraman for a CBS affiliate and prior to that performed work related to weather modification at the Utah Water Research Lab while also producing commercial light shows and devices for entertainment type productions. == Position at Ralcon == Ralcon Corp. is a vehicle for Mr. Rallison to consult in Optics and develop products. He owns an 8000 square foot facility in Paradise, Utah where laser and Holographic Optics development work has been going on since 1985.The facility is equipped with Argon, Yag, Dye, Nitrogen, HeNe, Ruby and various Diode lasers. Four floating stable tables of various sizes in well insulated rooms provide the basic optical beds and each has its own Argon, HeNe and YAG laser. A machine shop with a variety of glass shaping and polishing machinery compliment the holographic optical fabrication facility. Ralcon Development Lab (RDL) ceased commercial business in June of 2004 at the request the Cache County planning and zoning commission. Commercial customers of RDL have been referred to Wasatch Photonics in Logan UT, which was created in part to continue the work of RDL. Work at RDL is limited to research for NASA GSFC and other government labs. == Professional Affiliations == *Institute of Electrical and Electronic Engineers *Sigma Tau (Honorary Society) *Society of Photo Optical and Instrumentation Engineers(SPIE) *Optical Society of America (OSA) *Aircraft Owners and Pilots association (AOPA) == Licenses == *First Class Radio Telephone *Private Pilot, SEL, RH, Glider, Hang Glider *CDL -class A-air-trailer == Patents == * #4,913,990 "method of tuning a volume phase hologram" * #5,303,085 and #5,619,377 "Optically corrected helmet mounted display" * #4,950,067 "optical system that helps reduce eye strain" * #5,291,316 "Information display system having Transparent Holographic Optical Element" * #5,602,657 "Hologram system having hologram layers with rotationally offset Bragg planes" * #5,519,517 "Method and apparatus for holographically record and reproduce images in a sequential manner" * #6,097,543 "Personal Visual Display" * #5,991,087 "Non-orthogonal plate in a virtual reality or heads up display" * #5,991,085 "Head mounted personal visual display apparatus with image generator and holder" * #5,949,583 "Head mounted display with image generator, fold mirror and mirror for transmission to the eye position of the user" * #5,945,967 "speckle depixelator" * #5,903,396 "Intensified visual display" * #5,903,395 "Personal visual display system" * #5,864,326 "Depixelated visual display" * #5,751,425 "Raman spectroscopy apparatus and a method for continuous chemical analysis of fluid streams" * #6,100,975 "Raman spectroscopy apparatus and method using external cavity laser for continuous chemical analysis of sample streams" * #5,673,151 "Image correction in virtual reality and heads up displays" * #5,642,227 " Optical correction for virtual reality and heads up displays" * #6,678,079 “Transceiver for a wireless optical telecommunication system “ * #6,608,708"System and method for using a holographic optical element in a wireless telecommunication system receiver” * #6,369,952 “Head-mounted personal visual display apparatus with image generator and holder” * #6,160,666 "Personal visual display system” == Awards == *Dept of Defense SBIR Quality Award == Publications == Follow &lt;a href="/web/20080514140659/http://www.xmission.com/~ralcon/publications.html"&gt;this&lt;/a&gt; link to see our publications list, including links to online versions when available. [[Category:People]] [[Category:Rallison]] 04a18739831ba26439bdc17b4a537e3653119c1a 0 829 1700 2013-04-26T00:57:04Z Admin 0 wikitext text/x-wiki Richard D. Rallison == Abstract == The term "dichromates" may have started with Lloyd Cross, all I can recall is that I traded him a pocket full of "dichromates" for a "kiss". We were at the school of holography on the Santa Monica beach at the time. The first recording in Dichromated gelatin that I was privileged to see was made a year earlier by Mike Foster in the city of salt and he may also have used the term "dichromates". Mike and I were both working rock concerts in Utah from about 1965 to 1972 and got together from time to time to discuss science stuff and in particular an article in Popular Science written by Harry Knowles of Metrologic Instruments detailing the procedures for making a simple transmission hologram. I helped Mike prepare a lab and he made the first silver grain hologram I had ever seen. He chose a metal pig borrowed from the desk of weird Harold, who paid for everything at the time. I set up my own sand box lab after that, studied as many holography papers as I could find, made phase gratings, wrote my first paper on holographic gratings and then moved to LA to work at Hughes as an EE. A year later, 1974, I began production of the first dichromate jars, followed by the ubiquitous dichromate pendant, watch face, key fob and belt buckle in 1976. At my first SPIE meeting in San Diego in 1977, I sold dichromates in the halls. I carried a briefcase full of pendants with a covered display on the outside. Sales were brisk and I often had to retreat to my van to restock the briefcase. SPIE policy forbade such activity so I had to move around a lot to avoid Sue Davis. That was pretty much the beginning of a cottage industry. == Hooked on Optics == This paper is a brief journey from my first introduction to display optics to a career in holography. It is anecdotal experiences more or less presented in order of occurrence and has no technical merit. It represents my best effort at story telling and may not even be accurate. My journey began at the New York world fair of 1965 at the General Electric exhibit. GE had constructed a huge color organ using Rolux multi-lens sheeting to give the back lit screen a three dimensional appearance. I went home to Utah for my second year at USU and duplicated the device with help from a GE engineer and began selling them to bars. In 1966 I saw my first professional light show produced by Jerry Abrahms called "head lights" and quickly copied his equipment and made up some new effects of my own. Fred Unterseher was a part of Jerry's crew. I had built a large color organ in the likeness of an umbrella over the audience and so I called my show the "Electric Umbrella", a name I continued to use through my early years in holography. This was really fun stuff, I used colored oils and colored water between large clock faces to make dynamic amoeba looking projections onto screens, walls and ceilings. I cut holes in colored gels and rotated them slowly in front of de-focused slide projectors to create a flowing, ever changing colorful background and then superimposed sharp exploding images strobed by faster wheels and multiple projectors. Then I made slides from birefringent tapes and spun polarizers in front of projectors and I had built a few strobe lights from surplus electronics to annoy everyone with. I was probably born to be a photon junkie. {| border="1" |- | [[File:RDRLightshow.jpg]] | [[File:RDRFred77.jpg]] |- | RDR in 1967, operating a light show projector, (oils), in a very tiny projection booth. | Fred Unterseher in 1977, San Diego SPIE |} === Mike Foster === There was another light show operator in Utah at that time and I managed to meet him sometime during or between gigs. He was a fascinating and very sharp character named Mike Foster and his show was known as "five fingers on my hand". He had all the right stuff and knew how to use it and his connections were good. Eventually he helped me get a gig with the Steve Miller band in Feb of 1969 and allowed me to play with his new He Ne laser at a Pink Floyd gig in about 1970. Light shows went all Laser sometime after that and our projector based shows faded out. In 1972 I was building my first dye laser and Mike had just built an Argon laser (neither laser ever worked). One day he brought in a copy of Popular Science that had an article on how to make a hologram. We built a little black room and placed a granite slab on an inner tube and he made a hologram of a metal pig, borrowed from weird Harold's desk.. I thought it was cool but he saw a future in it. I continued on with EE studies and graduated and moved to LA to work at Hughes where I could play with more lasers and maybe make some that worked. My first trip back to Utah to ski I stopped in to see mike and he had made an 8 x 10 dichromate of David and finally I saw a future in holography. I had done some initial library research on all that was published up to 1973 and had passed it on to Mike and he had reproduced literally everything and already had developed proprietary and novel methods of making embossing masters. He was way out there. {| border="1" |- | [[File:RDRMikef.jpg]] | [[File:RDRLloyd.jpg]] |- | Mike Foster about 1976, SLC | Lloyd Cross 1977, San Diego |} === The early dichromate pioneers === In October 1968 T A Shankoff of Bell Labs published the first dichromated gelatin paper followed quickly by L H Lin, then Brandes and Curran also from Bell Labs. The reporting was quite complete and laid the groundwork for all other investigators. In 1971 Milton Chang of Northrop published an improvement using fixer and temperature to reduce milkiness while Pennington and Harper of IBM explored silver grain sensitized DCG. IBM researchers, Fillmore and Tynan found agreement with Lin's earlier work on photo induced index modulation. Meyerhoffer did an independent study at RCA and more clearly defined the micro-structure. About 1973 the torch was passed to Hughes Research labs where Don Close, Andrejs Graube and Gaylord Moss began cooking up HUDs and publishing very thorough research on dye sensitized gels. McCauley put DCG on Plexiglas that year as well. Mike F. visited HRL and made his first DCG in '73. My first followed early in 1974 while working at Hughes Laser Division, Culver City, CA. In 1975 Kubota began publishing red sensitizing followed in 1976 by BJ Chang at ERIM on reprocessing. In 1977 much of this was put in an orange reference book published by Springer, the DCG author was Meyerhoffer. I was tutored by Andrejs Graube from time to time and he visited my first production lab (garage) in the south bay area in 1975. I wrote my first DCG paper in 1979 based on experience with manufacturing and information from Andy, who was the only one of the early researchers that I ever got to know as a close friend. He continued to work in the field and published through 1979 at least. I think I am the only worker in the field, that started before 1975, that still depends mostly on DCG for a living. Every one else graduated from class and moved on and I am still repeating Shankoffs original experiments with hardly any changes into the year 2000. In Russia, Uri Denisyuk invented the single beam reflection geometry way before DCG was discovered. Single beam geometries worked perfectly with DCG because of the easily adjusted absorption and a huge dynamic range. I probably should have been paying him royalties in the seventies because almost everything I made was shot single beam at Brewster's angle. When I finally met Uri, I was relieved to learn that he was not concerned about my popularizing his techniques. {| border="1" |- | [[File:RDRUri.jpg]] | [[File:RDRHarry.jpg]] |- | Uri Denisyuk at recent SPIE (trying to collect royalties) | Harry Knowles 1995 at Metrologic |} === Serendipity === Back to the story, I returned to Hughes with one of Mike's broken 8 x10 inch dichromates determined to produce my own, Mike was not about to share more of his tricks of the trade so I was on my own. I coated Knox unflavored gelatin "'''Jello'''" on glass plates in my apartment using a record player built into an old steamer trunk. The dichromate processes described in the literature by Shankoff, Lin and Chang were all too time consuming to suit me. Mike had suggested during a phone conversation that I mix in all the sensitizing dichromate before coating to save some time and that helped. Everything I made initially came out milky white until I accidentally dropped an exposed plate into Milton's hardening fixer prior to soaking it in water. It was only in the fixer for 30 seconds but that proved to be sufficient to harden it enough to take the shock of hot alcohol without precipitation. A short process was immediately at hand. From then on I could make coatings on any glass surface in 5 minutes, expose them in another 5 minutes, process them in another 5 minutes and seal them up in less than 5 minutes. I immediately produced a few boxes full for show and tell and then lit the lab on fire. I managed to keep that trick under my hat until 1982, when Fred Unterseher persuaded me to publish it. I inadvertently also sold it to Steve McGrew (Holosonics) in 1979 and thought he might make it public just as I was selling it to IBM, but he never did publish. What he did publish was a very fine paper on color control in DCG in 1980, one of the first papers useful to artists working in color at the time. My method of controlling the color and clarity of master holograms was not disclosed til 1985. I dropped a developed broadband hologram into a certain bath that was about 75% alcohol and when I retrieved it and dipped it in hot dry alcohol it came back as a low scatter blue hologram. From that day in Nov 1975 I had a fast, tunable way to make bright masters that added almost no noise to the copies and so I finally had all the processes I needed to start making masters and churning out thousands of bright "dichromates" for sale. Which is what I did. {| border="1" |- | [[File:RDRPendants.jpg]] | [[File:RDRSpike.jpg]] |- | Dichromates, 1977 collection | Spike Stewart designed the first eyeglasses, 1977 |} === Accidents that counted === The spring of 1974 saw the opening of the LA school of holography on the Santa Monica beach and I finally met Lloyd Cross and many of the other originals from the San Francisco school of holography. I learned what I could from them and swapped dichromates for multiplexes and rainbow holograms. Lloyd gave me a great copy of his "kiss" multiplex for a handful of dichromate gems and I promptly destroyed it in one of my alcohol fires, which also got me thrown out of my slightly charred apartment, which resulted in my subsequent marriage to my wife of 25 years, Ruth Caird, whose prior husband was my office mate at Hughes. My future at Hughes was compromised somewhat by two unplanned attempts to burn down building six while processing dichromates. The last thing I learned to make while still employed there were the dichromate Apothecary jars filled with coins and a watch works nested in each one. These items were picked up by Selwyn Lissack and sold in NYC. I made about 24 of them each week in my garage in Lawndale California. They were made with a 7 mw cadmium laser purchased from the same Harry Knowles that wrote the original hologram article that Mike found. I started every Saturday the same way, mix up and filter a quart of yellow Jello, coat and shoot and process, drink a little wine, and then try to glue the caps on them. {| border="1" |- | [[File:RDRJarbatch.jpg]] | [[File:RDRJarsall.jpg]] |- | Original experimental jars and glasses | Production of apothecary jars |} A little wine and beer caused a few more accidents, like the time I lost control behind a speedboat at about 85 mph and skittered across the water right up on shore losing my ski and the whole back of my pants. Another time I was flying a hang glider behind a boat on the Colorado river when I got too far out to one side and crashed, breaking up the glider and shredding my levis. Then there was the time I rode a bicycle into a reservoir ripping my foot open to the bone, Ruth took me in to get stitched in Fresno which led to getting hitched to her in LA. In between I almost lost my foot to a bone infection which was only discovered when I broke the same leg (sliding down a banister) at Dodger stadium. If I had not broken my leg the infection would have gone undetected long enough to require an amputation .It was as my foot healed that I had my only boiling acetone fire, the landlord asked me to move immediately so I asked Ruth to marry me and help keep me out of trouble and she did. I have never had another alcohol or acetone fire since then and have learned to keep the alcohol in the process tanks and not in me. {| border="1" |- | [[File:RDRGabor75.jpg]] | [[File:RDRJar.jpg]] |- | Dennis Gabor and wife next to Selwyn Lissack about 1975 | Selwyn says, "I made this dichromate jar just for you." |} === Leaving LA === In 1975 we moved to Utah to build Argon Lasers at American Laser and Selwyn asked me to make pendants for him. He put me into business single handedly but his early attempts to take credit for the production of the dichromates provided some truly hysterical moments at the SPIE San Diego conference of 1977. By that time I had been selling pendants to the Goldberg boys at Holex and had supplied a few other dealers on the west coast and the museum of holography in New York. Rosemary (Posy) Jackson, of the MOH, turned to me several times during the conference and mouthed out the phrase "I made those dichromates" causing major rib damage from laughter. My first production lab in Utah was in the basement of a house at 3488 E 7590 S, which is more or less at the mouth of Big Cottonwood Canyon and occasionally I would go skiing on a lunch break. We were 11 minutes from the lower chair lift at Snowbird. I can no longer remember who went with me but Jerry Heidt may have been one, we occasionally went cow trail motor cycling and skiing during all the years that he worked in three or four of my labs. Rick Lowe was my first employee and I think Jerry's brother was my second. Rick and I had motor boats and would take everyone to lake Powell for water skiing from time to time. At one time I had 8 to 10 people working in my basement. I never intended to manufacture in the mass production sense and tried farming out the production several times over ten years. It moved to Richland Washington once when patent issues were hot and Holosonics (Holotron) insisted on trying to cash in on what ever I was doing. In 1979 Lee Dickson came calling from IBM and we made a fine looking holographic scanner for him. I thought I finally had a good reason to want to manufacture something. The first day he visited, he needed a little evidence that we could actually make dichromates in the little suburban house we owned at the time so we took his watch and sat him on the couch upstairs while Rick Lowe and I went down and made a nice reflection hologram of his watch. It took about 15 minutes and then we brought it up and gave it to him, he seemed impressed. We quickly struck a tentative product development deal and moved the operation into a chicken coup in Draper while we built a brand new building just for the production of holographic scanners. IBM negotiators came out to firm up a technology buy while we were operating in the chicken coup and they came on one of those days when my cat had sneaked in and left a load on my desk. They were not impressed. We only asked for $50k to transfer the disc making technology but learned in later years that they were prepared to pay perhaps 10 times that much. Nevertheless, I thought it was a fair price and I found a good friend in Lee Dickson so it was all worthwhile. IBM pulled the plug after nearly two years of development and production. We helped set up a production line in North Carolina where they made their own discs for the next 7 years. We used the new building to make larger plates and pendants and pulse portraits and even took the company public in a lame sort of way. I figured out eventually that I am a sole proprietor type of entrepreneur. The lessons cost me a few friends and partners. {| border="1" |- | [[File:RDRScanners.jpg]] | [[File:RDRRdraust.jpg]] |- | Holographic Scanners for bar code reading and for printing, 1982 | RDR in Australia buying Boomerangs, 1987 |} === Laser Accidents === Mike and I had a great mutual interest in Lasers and struggled to own and build them as soon as they became available. I tried to make a dye laser from plans in Scientific American by Peter Sorokin. It was mostly built in 1971 and it nearly killed me at least once. I managed to get both index fingers across the flashlamp with the capacitor bank mostly charged. It discharged about 60 joules straight through my heart. I involuntarily threw the laser across the room into a wall and broke the lamp. Mike made an Argon laser and managed to violently blow the bulky Brewster windows off the ends with high Argon pressures. My best accident was while at Hughes developing a CO2 waveguide laser. The power supply was 10KV at 100ma dc and protected by a painfully slow mechanical breaker. I worked with one hand behind my back but I hardly ever turned off the power to make adjustments because all the surfaces I touched were insulated, or so it appeared. The insulation broke down Nov 23^rd 1974 and a kilo-watt of power flowed into my thumb and out of a circular patch on my belly, blowing a section of my shirt right into the air as the current found a ground in a metal cabinet. My legs extended and my arm struck my chest as I flew backward and upward onto a wall 4 or 5 feet behind me. It seemed as though I were looking down a tunnel from somewhere about 20 feet behind my body and I was partially paralyzed. I wrestled with paralysis for ten or twelve minutes and then felt pain along the track the current took for a few days. I got married 3 days later and was always glad that my belly was closer to the cabinet than was my zipper. The hole in my belly and shirt was the size of a dime and somewhat charred. I once had a Coherent cadmium laser that had a negative high voltage on each of the mirror mounts and it required frequent fine tuning. The voltage was only about 2Kv and it was possible to use two ball end drivers with plastic handles to do the work as long as you never slipped off the plastic. About the 10^th time re-tuning with this head cradled in my lap, I slipped and took the full voltage across my chest again and the poor laser flew across the room into a wall, breaking the tube. === Throwing in the towel === 1984 was my last year making pendants, I had failed as a business manager in multiple ways and made the decision to sell the company to the first interested party with a little cash. I sold it to the wrong group of guys and ended up paying out tens of thousands of dollars in subsequent years just to cover the debts they created for me. I moved to Paradise and started over from scratch, making nothing but holographic optical elements. The original Electric Umbrella went through numerous name changes and ownerships and evolved roughly into Krystal Holographics, now owned by Dupont. Jerry Heidt is the only remnant from the original basement operation. I imagine that if I had been a better manager and had resolved conflicts with Mike and Rick and Jack and Larry and Jerry and Scott and some backers and bankers and candlestick makers that I could have had a much more successful early venture in holography. I have learned those lessons and have determined that too much energy has to go into growing a successful business venture. During the year or so that I tried to capitalize and grow I missed the time in the lab, the study time, the new technologies to be learned. Those things get neglected when business interests dominate. I call myself a lab manager now and that is about the extent of the responsibility that I take on whenever I can get away with it. {| border="1" |- ! colspan="2" | (About 1982 or 1983) |- | [[File:RDRRick.jpg]] | [[File:RDRJack84.jpg]] | [[File:RDRJerry83.jpg]] |- | Rick Lowe, first employee, 1976 | Jack Worthington, partner | Jerry Heidt, 1980, still at it |} === Flying for relaxation === {| border="1" |- | [[File:RDR500inst2.jpg]] | [[File:RDRGt500rdr93.jpg]] |- | My GT-500 | A boy and his 7^th airplane |} I took up flying once again after moving to Paradise, this time I taught myself to fly ultralight aircraft rather than hang gliders. On one sunny late August afternoon I lifted off to chase water skiers at the local lake in a machine best described as a flying lawn chair. I swooped down on them from behind and above only to pull up sharply as I roared past like a big scary bumblebee. On the last pass I pulled up along side of a skier and while I looked at his startled expression and waved I let my front wheel dip into the water and with a loud slap I hit the water, broke off a wing and proceeded straight to the bottom, landing upside down in thick mud, 22 feet below the surface. It was dark when I regained my senses and I carefully unbuckled my seatbelt and worked my way past the flying wires which were laying in every direction. Then when I was free I tried to swim up but only buried my head in the mud. I had no air in my lungs to float up with so I took my white foam filled helicopter helmet off and held it by the communication cord and let it guide me to the surface. I gulped air just as my vision faded to black. I never experienced a moment of panic and would have died pleasantly in a few more seconds without oxygen. The lake ranger who had been chasing me all summer helped me haul the wreckage out of the water but would not stop laughing the whole way in to shore. I rarely fly that low across water any more and have since survived five more crash landings in various off airport locations. I flew right into a mountain with a passenger, then into a barbed wire fence, cracking a rib, I landed in a tree once and most recently flew into a 7.5 kV power line. It hurt a lot. Earlier that day I had buzzed Sharon McCormack and her boy friend at Hood River and had flown down into Mt St Helens volcano and over Mt Rainier so I was feeling invincible. A thunder storm and a moonless night conspired to keep me from seeing the ground. I hooked the power line with the nose wheel, stripped it off the pole and broke it before free falling into a hay field. My feet went right through the fiberglass shell and aluminum pedals and 6 inches into the dirt. === Outside ventures === Fred and I taught a crew in England (Raven) how to make dichromates and they did a great job of it but could never make enough money to stay in business. I taught a group in Kansas (Portson) once how to do it and they did a good job but had trouble staying in business also. I helped out Paula Dawson for a trip to Australia and some change in 1987 and I taught a lot of people at the annual school at Lake Forest College but none of them have made businesses that I know of. Dichromates have largely been replaced with cheaper mass produced photopolymer holograms. The medium still works best for high performance diffractive optics and probably will for a long time to come. Bright, clean DCG masters are still made for copying into photo-polymers. I joined Lee Dickson and two other x IBM engineers in a venture called Holoscan a few years ago and we bought back all the Scanner making technology from IBM. We made some product and then sold the company to Harry Knowles, still the owner and CEO of Metrologic instruments. I became the teacher and taught Harry and his crew how to make dichromated gelatin holograms some 25 years after he taught Mike and I how to make our first holograms. Harry is a really great guy and he runs the only production line I know of today that makes bar code scanners on glass plates using dichromated gelatin. He also sent me a lot of Habanero pepper sauces for Christmas this year, he is very thoughtful (thanks to his wife). I also taught technicians and engineers at APA, Northrop, Process Instruments, Terrasun and Terrabeam and a few other places how to cook yellow Jello. I also teamed up with a group in Seattle (Virtual I/O) about 1990 and we designed and manufactured head mounted displays (HMDs) for a few years. Eventually the major stockholders discovered we were selling them for less than the cost to manufacture them and they pulled the plug. You can still buy the HMD sets but they cost a lot more now and I don't own any part of the new company. I am still actively involved in a Laser Com business in the Seattle area and have assisted in setting up a production line for Large area holoscope receivers but don't plan to move there any time soon. My lab has been supported through the 90s with several NASA contracts to make ever larger LIDAR scanners. We are currently doing our best to put out dichromated gelatin HOEs that measure nearly a meter in diameter. These HOEs are being made to conically scan the skies at multiple wavelengths and to have a field of view of only a hundred micro-radians. These are by far the most challenging projects of my career, and therefore the most fun. We have been making HOES of 400 mm diameter for ten years but the year 2000 will be the year of our first meter size optics for use in the near UV region. We have also been making a lot more gratings for spectrographs in the past few years, and the pace appears to be picking up along with the size and the price. I imagine that the business opportunity is now better for me than it ever was before. It is a bit of a shame because I have no desire to even try to grow a business and also don't know anyone else that does. I really enjoy assisting other businesses to make products and plan to just keep on doing that for work and play. I have 4 full time lab jocks and a grad student to keep busy and we are learning how to polish glass and how to operate high vacuum etchers and coaters in a new and larger lab. {| border="1" |- | [[File:RDRLab99.jpg]] | [[File:RDRNasa.jpg]] |- | Lab addition in 1998, another 4000 sq ft | LIDAR scanner for NASA |} === Significant Inventions === I have a few patents but they don't cover any of my real inventions. My first invention was a semi automatic jerky chopper and I built it when I was 18 years old. It cost about $90 to build from a furnace blower, a lawn mower and a few metal parts and was used commercially for over ten years. My next invention was a glue mixer. It cost $4.00 in parts and was made from a motorized stage light fixture and a plastic kitchen cup. It mixes glue in paper cups like a concrete mixer and generates no bubbles. Next I invented the first dynamic spatial filter. It consisted of a curved first surface mirror glued to a speaker cone and the speaker was driven by a hard rock radio station. It only worked well for contact copies using a single beam but it did work, and it cost about $10. I made a few odd fringe lockers but would never claim them as an invention. For Pilkington in 1982 I invented the hand held air gate method of making reflective head up displays and several years later another company (Flight Dynamics) patented it. I thought it was too trivial and obvious to ever get patented, but then many of us had to work under the infamous "claim 6", so nothing else that gets patented could ever be a surprise. Most recently I think I invented the "aperture scanner". It enables me to make big clean recordings with little lasers and consists of a rotating tilted window. {| border="1" |- | [[File:RDRPosyoffice76.jpg]] | [[File:RDRRandr.jpg]] |- | Rosemary (Posy) Jackson about, 1976. Quote from SPIE, 1977 "Psst!, I made those Dichromates!" | RDR and wife Ruth, recent SPIE meeting.<br> Mom and Pop running the business. |} == DCG References == See: [[DCG References]] [[Category:Rallison]] [[Category:DCG]] e021fcdcfd747b2bdbb134eb616806d5c1c6a875 0 818 1628 2013-04-26T01:02:09Z Admin 0 wikitext text/x-wiki === Early researchers (to 1974) === *T. A. Shankoff, "Phase holograms in dichromated gelatin" ''Appl. Opt.'' '''7:'''2101-2105, 1968 *T A Shankoff and R K Curran "Efficient, high resolution, phase gratings", ''App Physics Letters'' 13:pp239-241, 1968 *L.H. Lin, "Hologram Formation in Hardened Dichromated Gelatin Films." il ''Ap Optics'' 8:963-6 My, 1969 *H. Kogelnik, "Coupled wave theory for thick hologram gratings" ''Bell Syst Tech J.'' '''48''':2909-2947, 1969 *R.G. Brandes and others, "Preparation of Dichromated Gelatin Films for Holography." ''Ap Optics'' 8:2346-8 N, 1969 *R.K. Curran and T.A. Shankoff, "Mechanism of Hologram Formation in Dichromated Gelatin." ''Ap Optics'' 9:1651-7 Jl, 1970 *T.P. Sosnowski and H. Kogelnik, "Ultraviolet Hologram Recording in Dichromated Gelatin." ''Ap Optics'' 9:2186-7 S, 1970 *M. Chang and N. George, "Holographic Dielectric Grating; Theory and Practice" ''Ap Optics'' '''9''':713-719, March 1970 *L.H. Lin, "Method of Characterizing Hologram-Recording Materials." ''Opt Soc Am J.'' 61:203-8 F ,1971 *Milton Chang, "Dichromated Gelatin of improved optical quality", ''App Optics'', 10&nbsp;: p2550-2551, Nov 1971 *D. Meyerhofer, "Spatial Resolution of Relief Holograms in Dichromated Gelatin." ''App Optics'' 10:416-21 F, 1971 *Gary Fillmore, Richard Tynan, "Sensitometric characteristics of hardened dichromated gelatin films" ''J of Op Soc,'' 61:pp199-202, 1971 *K S Pennington, J S Harper, "New photo technology suitable for recording phase holograms and similar information in hardened gelatin", ''App Phys Lett'' 18: pp80-84, 1971 *W. S. Colburn, "Holographic Optical Elements", ''Technical Report, contract F33615-72-C-1156'', 1973 *F. T. S. Yu. "Effect of Emulsion Thickness Variations on Wavefront Reconstruction". ''App Optics'' '''10''':1324-1328 June 1971 *D. Meyerhofer, "Phase Holograms in Dichromated Gelatin.". ''RCA R.'' 33:110-030 Mr, 1972 *D. H. Close, A. Graube, "Materials for Holographic Optical Elements", ''Technical Report AFML-TR-73-267'', Oct. 1973. *A. Graube, "Holograms recorded with red light in Dye sensitized dichromated gelatin", Optics Comm.8:251-253 *D G McCauley, "Holographic Optical Element for visual display applications", App Optics, 12: 232-241, 1973 *D.H.Close, A. Graube, "Holographic Lens For Pilot's head up display", ''Techmical report, contract# N62269-73-C-0388'', 1974 *R D Rallison, "DCG applied with a record player and broadband processed in 2 minutes" ''Hughes Aircraft'', Jan 1974 (never published, just bragged a lot) === Additional selected DCG related publications (to 1996) === *S. K. Case. "Coupled Wave Theory for Multiple Exposed Thick Holographic Gratings". ''Opt Soc Am J.'' 65: 724-9 Je, 1975 *A.Alferness, S.K. Case, "Coupling in Doubly Exposed, Thick Holographic Gratings" ''Opt Soc Am J.''65:730-9 Je 1975 *R.V. Pole and H.P. Wollenmann, "Holographic Laser Beam Deflector". ''App Optics'' 14:976-80 Ap 1975 *S. K. Case, "Multiple exposure holography in Volume Materials", ''Doctoral Dissertation'', U of Michigan, 1976 *B.J. Chang, "Post Processing of Developed Dichromated Gelatin Holograms", ''Optics Communications'', '''17''' (3): 270-271, June 1976. *T. Kubota, T. Ose, M. Sasake and K. Honda "Hologram Formation with Red Light in Methylene Blue Sensitized Dichromated Gelatin" ''Applied Optics,'' '''15'''(2):556-558, Feb. 1976. *W. S. Colburn &amp; B. J. Chang "Holographic Combiner for Head-Up Displays", ''Technical Report AFAL-TR-77-110'' , Jan 1977 *H. M. Smith, ''Holographic Recording Materials,'' Springer Verlag, 1977 *A. Graube, "Dye Sensitized dichromated gelatin for holographic optical element fabrication" Photographic Sci and Eng, 22: pp37-41, 1978 *A. Graube, "Holographic optical element materials research", ''Technical report, Air Force contract # F44620-76-C-0064,'' 1978 *S.K. Case and W.J. Dallas, "Volume Holograms Constructed from Computer Generated Masks." ''App Opt'' 17:2537-40 Ag 15, 1978 *R D Rallison, "Fabrication of a holographic scanning disc" ''Technical report to IBM'', Raleigh NC, 1979 *R D Rallison, "Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)."''SPIE Proceedings'' 212:22, 1979 *B.J. Chang and C. D. Leonard, "Dichromated Gelatin for the Fabrication of Holographic Optical Elements", ''App Opt'' 18:2407-17 Jl 15, 1979 *S.P. McGrew, "Color Control in Dichromated Gelatin Reflection Holograms", ''Proc. SPIE'' '''215''':24-31, 1980. *B.J. Chang, " Dichromated Gelatin Holograms and Their Applications". ''Opt Eng'' 19:642-8 S/O, 1980 *W.R. Graver et al, "Phase Holograms Formed by Silver Halide Sensitized Gelatin Processing" ''App Opt'' 19:1529-36 My 1, 1980 *S.K. Case et al, "Multi facet Holographic Optical Elements for Wave Front Transformations". ''App Opt'' 20:2670-5 Ag 1 1981 *Sven Sjolinder, "Dichromated Gelatin and the Mechanism of hologram formation", ''Photo Sci and Eng'', 25: pp 112-117, 1981 *D. A.Winick, "Thick Phase Holograms", Environmental Research institute of Michigan, Level, January 1981 *L. Solymar &amp; D.J. Cooke , ''Volume Holography and Volume Gratings'', Academic Press, 1981. *J. Oliva et al, "Diffuse-Object Holograms in Dichromated Gelatin." ''App Opt'' 21:2891-3 Ag 15, 1982 *H. Bartelt, S.K. Case, "High-Efficiency Hybrid Computer-Generated Holograms." ''Appl Opt'' 21:2886-90 Ag 15,1982 *R D Rallison, "Hologram Scanner Design and Fabrication in Dichromated Gelatin (DCG)." Proc SPIE, August, 1982 *R D Rallison, "Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College *First International Symposium on Display Holography, July 1982 *L.D. Dickson, "Holography in the IBM 3687 Supermarket Scanner", ''IBM J. Res &amp; Devel'' 26:228-34 Mr 1982 *.J.E. Ludman, "Approximate Bandwidth and Diffraction Efficiency in Thick Holograms." ''Am J. Physis'' 50:244-6 Mr.1982 *Tung H. Jeong, ''Proceedings of the International Symposium on display holography,'' Vol I 1983 *Y.-Z Liang, "Multifocus Dichromated Gelatin Hololens". ''Appl Opt'' 22:3451-6 N 1 1983 *A. Fimia, "Noise Reduction in Holographic Images Reconstructed with Blue Light". ''Appl Opt'' 22:3318 N. 1, 1983 *J. Oliva et al, "Dichromated Gelatin Holograms Derived from Agfa 8E75 HD Plates" ''Appl Opt'' 23:196-7 Ja 15 1984 *R D Rallison, "Characteristics of Dichromated Gelatin (DCG) Scanners for Printing Applications"''Proc. SPIE''. 498: 199, 1984 *R D Rallison,"Applications of Holographic Optical Elements" Lasers and Applications,pp61-64 December 1984, *S. Calixto and R.A. Lessard, "Real-Time Holography with Undeveloped Dichromated Gelatin Films" ''Appl Opt'' 23:1989-94 Je 15, 1984 *Ryszard Gajewski "Holographic Technology for Solar Energy Concentration" ''Technical Report No. 87-1479'', 1984. *C. Solano, Lessard et al, "Red Sensitivity of Dichromated Gelatin Films".''Appl Opt'' 24:1189-92 Ap 15 1985 *J. C. Newell et al, "Holograms in Dichromated Gelatin: Real-Time Effects" ''Appl Opt'' 24:4460-6 D 15 1985 *Jose R. Margarinos &amp;Daniel J Coleman "Holographic Mirrors" ''Proc. SPIE'' '''523''':203-218, 1985. *C. Solano and R.A. Lessard, "Phase Gratings Formed by Induced Anisotropy in Dyed Gelatin Plates" ''Appl Opt'' 24:1776-9 Je 15 1985 *Richard D. Rallison, "Holographic Optical Elements (HOES) in Dichromated Gelatin (DCG)", ''Proc. SPIE'' '''523''':292-295 (1985). *S. Calixto et al "Real-Time Optical Image Processing and Polarization Holography with Dyed Gelatin". ''Appl Opt'' 24:2941-7 S 15 1985 *Tung H. Jeong, P''roceedings of the International Symposium on display holography'' Vol II 1986 *T. Kubota, "Recording of High Quality Color Holograms" ''Appl Opt'' 25:4141-5 N 15 1986 *P. Hariharan, "Silver Halide Sensitized Gelatin Holograms: Mechanism of Hologram Formation." ''Appl Opt'' 25:2040-2 Jl 1, 1986 *R. Changkakoti and S.V. Pappu, "Study on the pH Dependence of Diffraction Efficiency of Phase Holograms in Dye Sensitized Dichromated Gelatin." ''Appl Opt'' 25:798-801 Mr 1 1986 *C. Solano et al Methylene Blue Sensitized Gelatin as a Photosensitive Medium for Conventional and Polarizing Holography" ''Appl Opt'' 26:1989-97 My 15 1987 *Daniel K. Angell, "Improved diffraction efficiency of silver halide (sensitized) gelatin", ''Appl Opt'', 26:4692-4701,1987 *R D Rallison,"Holographic Scanners for Machine Vision, Printing, and Bar Code Applications." Proc. SPIE 747:pp 1987 *H K Liu, "Simplified dichromated gelatin hologram recording process", ''App Optics'', 26:372-376, 1987 *D.J. Jacobs and M. G. Marsland, "Reduction of Sensitizer Concentration Gradients in Dichromated Gelatin Films" ''J Phys E''. 20:899-901 Jl 1987 *R. D. Rallison, "Materials for Volume Phase Holographic Notch Filters" ''SBIR #A 86-68 Final Report'', U.S. Army CECOM, Ft. Monmouth, N.J. Aug.1987 *Jon D. Masso "Multilayer Thin Film Simulation of Volume Holograms" ''Proc. SPIE'' '''883''':68-72, 1988 *R D Rallison, "Cascaded Transmission Holograms for Head-Up Displays". ''Proc. SPIE'' 883: pp 1988 *N. Capolla and R.A. Lessard, "Processing of Holograms Recorded in Methylene Blue Sensitized Gelatin" ''Appl Opt'' 27:3008-12 Jl 15, 1988 *R. D. Rallison "Incoherent Multifocus Hololens design and fabrication", ''Proc. SPIE'' '''1183''':663-668 1989 *R. D. Rallison "Survey of properties of volume holographic materials", ''Proc. SPIE'' '''1051''':68-75 1989 *James M Tedesco, "Holographic laser -protective filters and eye-wear" Opt Eng 28:p609-615, 1989 *Y. Amitai et al "Holographic Elements with High Efficiency and Low Aberrations for Helmet Displays", ''Appl Opt'' '''28''':3405-3416 Aug 15 1989 *J. L. Salter and M. F. Loeffler, "Comparison of dichromated gelatin and Dupont HRF-700 photopolymer as media for holographic notch filters" ''Proc. SPIE'' '''1555''':268-278 (July 1991) *Chris Rich, David Cook, "Lippman volume holographic filters for Rayleigh Line rejection in Raman Spectroscopy", Proc. SPIE 1461:2-7, 1991 *R. D. Rallison, "Control of DCG and non silver holographic materials" ''Proc. SPIE'' '''1600''': 26-37 1991. *R D Rallison,"Polarization properties of gelatin holograms" ''Proc''''. SPIE'' 1667:pp 1992. *R D Rallison, "Using Thick DCG, 30 to 100 microns" Proc. SPIE 1914:pp 1993. *L D Dickson, R D Rallison et al, "Holographic polarization-separation elements" ''Appl Opt''. 33:5378-5385, 1994 *R. D. Rallison and S. R. Schicker, "Wavelength compensation by time reverse ray tracing", ''Proc. SPIE'' '''2404''': 217-225 1995 *Hans Dieter Tholl, "Polarization properties of volume phase gratings", ''Optical Engineering'', '''34'''(10)2879-2885 Oct 1995 *Hans I Bjelkhagen, ''Holographic Recording Materials'', SPIE publications, 1996. *R D Rallison, Steve Arnold, "Wavelength compensation at 1.064 microns using hybrid optics" Proc SPIE 2689, 1996 [[Category:Rallison]] [[Category:DCG]] 45265f7eb8e91d55d9b9ef3aadcc5f8e57b14744 0 822 1654 2013-04-30T00:41:10Z Admin 0 Created page with "<br> [[http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-21-4-4044 Speckle-free, shaded 3D images produced by computer-generated holography]] <br>" wikitext text/x-wiki <br> [[http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-21-4-4044 Speckle-free, shaded 3D images produced by computer-generated holography]] <br> 5f2ca782670e7ea128e5eff6e00ef136bfed8da1 10 857 1862 2013-04-30T02:58:37Z Admin 0 Created page with "{{#if: {{{1|<noinclude>demo</noinclude>}}} | <div class="note note-{{#switch:{{{2|}}} |gotcha=error |=info |#default={{{2|}}} }}">{{{1}}}</div> | [[File:Bulbgraph.png|18px|Not…" wikitext text/x-wiki {{#if: {{{1|<noinclude>demo</noinclude>}}} | <div class="note note-{{#switch:{{{2|}}} |gotcha=error |=info |#default={{{2|}}} }}">{{{1}}}</div> | [[File:Bulbgraph.png|18px|Note|link=]]&nbsp;'''Note''': }}<noinclude> == Usage == <pre> {{note|Foo}} {{note|Foo|reminder}} {{note|Foo|error}} {{note|Foo|gotcha}} {{tip|Foo}} {{note}} Loose test {{tip}} Loose test </pre> {{note|Foo}} {{note|Foo|reminder}} {{note|Foo|error}} {{note|Foo|gotcha}} {{tip|Foo}} {{note}} Loose test {{tip}} Loose test [[Category:Templates|{{PAGENAME}}]] </noinclude> 7e966626f702a768022c74250cc9d54fe302d6d5 0 178 1600 204 2013-05-01T01:07:44Z Admin 0 wikitext text/x-wiki The backgrounds of holographers are extremely varied, as can be seen below. Without these people's tireless efforts, holography would have remained a mere laboratory curiosity, rarely to be seen elsewhere. As a result of their work, holographic techniques are more and more frequently used in science, technology, medicine, measurement and art. With the advent of lower cost lasers and recording materials, and also due to the work of the dedicated holographic popularizers among those listed below, there is a small but growing international community of amateur holographers, and it is not uncommon to have hands-on holography courses presented in elementary schools. This project is designed to collect in one place biographical info on all of the people who have made holography possible. Please feel free to post your biographies here. If you know a name but don't know the details, just add the name and we will work on getting a biography. *[[Dave Battin]] *[[Paul D. Barefoot]] *[[Kaveh Bazargan]] *[[Margaret Benyon]] *[[Stephen Benton]] *[[Rudie Berkhout]] *[[Hans Bjelkhagen]] *[[Jeff Blyth]] *[[Patrick Boyd]] *[[Pam Brasier]] *[[Harriet Casdin-Silver]] *[[Greg Cherry]] *[[Melissa Crenshaw]] *[[Loyd Cross]] *[[Salvador Dali]] *[[Rebecca Deem]] *[[Frank DeFreitas]] *[[Yuri Denisyuk]] *[[Georges Dyens]] *[[Phil Edelbrock]] *[[Gregg E. Favalora]] *[[Dennis Gabor]] *[[Yves Gentet]] *[[Andres Ghisays]] *[[Nancy J. Gorglione]] *[[Michael Harrison]] *[[Dr. Jeong]] T. J. *[[Frithioff Johansen]] *[[Pearl John]] *[[Colin Kaminski]] *[[John Kaufman]] *[[Roderic Lakes]] *[[Emmett Leith]] *[[Sharon McCormack]] *[[Mike Medora]] *[[Ronnie Michael]] *[[Lon Moore]] *[[Rob Munday]] *[[August Muth]] *[[Ikuo Nakamura]] *[[Anna Maria Nicholson]] *[[Caroline Palmer]] *[[Dinesh Padiyar]] *[[Joy Padiyar]] *[[John Pecora]] *[[Andrew Pepper]] *[[Hart Perry]] *[[Jerry Pethick]] *[[Nicholas Phillips]] *[[Greg Quinn]] *[[Rallison, Richard|Richard Rallison]] *[[Al Razutis]] *[[Jonathan Ross]] *[[Graham Saxby]] *[[Dan Schweitzer]] *[[Mark Segal]] *[[Walter Spierings]] *[[Anait Stephens]] *[[Fred Unterseher]] *[[Juris Upatnieks]] *[[Doris Vila]] *[[John Webster]] *[[Edward Wesly]] *[[Mieczyslaw Wolfke]] *[[Sergey Vorobyov]] *[[Sergey Zharkiy]] c4a417138390a799c205f56e9329a95231c77bb1 0 803 1554 2013-05-01T01:13:41Z Admin 0 wikitext text/x-wiki [[Category:Rallison]] [[Category:DCG]] == 2 and 3 Color Dichromates, Production Method == The two color method produces rich Red-Orange and bright clean Blue-Green colors that mix to a creamy white. Color coding of the object is optional but helpful in most cases and production is done from two masters in two different films. The three color system requires color coding for Red at the mastering stage but no coding for Blue or Green, which are mastered first. Both systems are part natural, part pseudo color and require only two laser lines and two film formulations. Blue is obtained naturally by using the 458 argon line and Green or Red are derived from the 514 line. In production the two color system is identical to current master/copy methods in that batches are shot at 458 or at 514 and later registered and laminated together. The three color system requires Blue and Green exposures in the same emulsion and Red in a second batch. The laser must then be operated multiline or be switched constantly or a second laser introduced. The preferred method is multiline operation with independent shuttering. The two color system makes very satisfying flesh tones and color balance is fairly easy to maintain because it can be done by mixing and matching batches and or individual holograms at the laminating stage.Object preparation is as follows, Blue-Green areas should be overcoated lightly with a bright blue pigment such as Liquitex Brilliant Blue #20002-381 or Pelikan Deep Blue #39. This will effectively inhibit reflection at 514. The Red-Orange areas must be touched up with Yellow pigment such as Liquitex #1002-411 or Pelikan Yellow #10 both of which absorb 458 but reflect 514. At this stage H1 masters or correctly colored copies can be made, the Blue-Green master may be made to reconstruct at 488 so that production copies can be done using only 488 and 514. The 514 exposure is done with the film side facing the reference beam and the 458 exposure is done the other way around with a spacer between the object and film having the same optical thickness as the 514 substrate. Formulas for each film and processing details are as follows. <font color="#FF0000">Red-</font>- mix 3-30-250 using Potassium Dichromate spin on at 80-90 RPM, expose single beam 90-100 mj\cmE2 @ 514 if RH = 60% and T = 70 F. Process: develop 5 min., rinse, 30 sec in 1HAB @ 120 F and .86 SG. Dry with slow pull from LHAB followed by hot air. Color should be bright Red-Orange. <font color="#1A1AFF">Blue-</font>-Mix 9-30-250 using Ammonium Dichromate, spin on at 80-90 RPM, expose single beam 24 mj\cmE2 @ 458 if RH = 60% and T = 70 F. Process: develop 3 min., rinse, 15 sec in 1HAB @ 120 F and .86 SG. Dry with slow pull, color should be bright Blue to Blue-Green. This film was 2-4 hrs old, shorten times for older film. For 3 Color system use 10-30-250 and expose twice, once with 24 mj @ 458 and once with 50 mj @ 514. Then code the object for Red and use the same red procedure. <br> (This paper was used for a class at Lake Forest College and was never published as is. The same information has been published in SPIE Vol 1600 mostly on page 35.) 554ac788a729ee611ae3b013f679c3664d6a7dc4 0 169 1586 186 2013-05-01T01:53:13Z Admin 0 wikitext text/x-wiki By: John Pecora Well, there has been some talk about tables and plate holders so I thought I might post my plate holder design. It is original and I like it better then any plate holder I have ever used or seen. It allows from a 4" to a 20" format. It is quick and easy to load, even in the dark. It is very stable. I tried to put notes in the drawing to describe how it works but feel free to question anything. Also feel free to use the design if you want. It is all steel construction. The vertical poles are solid 1 1/2" rods. The angle iron on the top has holes cut out for the poles, but the holes are slightly larger. There is no need to have the holes and rods within close tolerances. The top angle iron simply rests on the plate via the 2 sets of 2 screws as described. Then the thumbscrew is turned to place a slight bit of pressure from the angle iron to the pole to take the "ting" out but no stressing is involved as the large holes in the angle iron allow the angle iron to float freely, tilting to and away from the pole with the turn of the screw. The design of the top shades the very top part of the plate so nothing else is needed to keep the light from entering the edge of the plate. Another nice feature is there is room to squeeze light very close to the plate on the inside or outside of the pole depending on actual film plate size. [[Image:PecoraPlateholder.jpg]] [[Category:Pecora]] [[Category:Equipment]] a0d64de29ce029884a095401d707e877038690aa 0 395 1728 942 2013-05-01T02:38:27Z Admin 0 wikitext text/x-wiki [[Image:JBlyth.jpg|right]]After graduating in 1973 in Applied Chemistry he worked in a company with dichromated gelatin, unrelated to holography. In ’77, he was amazed to see a holographic pendant made using the very material he was researching. His life ‘changed for ever’. He subsequently worked on photopolymer materials for Ilford, which became the subject for an MPhil at Wolverhampton Polytechnic. Since ’91 he has been involved in ‘blue sky’ research at the Institute of Biotechnology in Cambridge, UK. Jeff is the recipient of the Royal Photographic Society’s Saxby award for 2003. [[Category:People]] 6575d9c9f7569381762617c9a4e6386cc626e157 0 237 1678 322 2013-05-01T02:42:50Z Admin 0 wikitext text/x-wiki [[Image:FDeFreitas.jpg|right]] [http://www.holoworld.com HoloWorld] Frank started holography in 1983. While having no formal training in science, he has made a career in science and technology. He runs [http://www.holoworld.com HoloWorld], perhaps the most popular web site for holography. He is one of the pioneers of using laser pointers to make holograms. He is the author of ''Shoebox Holography'' and runs an internet radio program, [http://www.holoworld.com/holotalk/index.html HoloTalk]. He also teaches holography to childeren in workshops. [[Category:People]] 8952181bbc5e99c9078ac2642350f65bfa5dd2b8 0 428 1750 1007 2013-05-02T00:34:33Z Admin 0 wikitext text/x-wiki ====A Machined Film Holder==== by: Colin Kaminski '''4" x 5" Film Holder''' after Dinish and Joy Padyir's. [[Image:FilmHolder.gif|right]] This film holder is a copy of one Dinesh and Joy were using when I was there. I made it from 3/4" square aluminum bar. (This is not quite how I made it but I am going to include how I would make it again when I make a second one this week.) Take a 12" or so section of 3/4" aluminum bar and set a table saw to cut .25" deep. Set the fence .125" from the blade (make sure the fence is parallel to the blade!) Run the piece of aluminum through. (Use two push sticks so you don't get your hands anywhere near the blade. Also a feather board or two would be of use but I did not have any handy.) Then move the fence over about .035 inches or however wide you want the slot. You can make the slot wide enough to accommodate 2 plates and film if you wish. Then hack saw it to 4.25" or so. (Where the table saw blade exited the part you will notice the slot is wider than the rest of the part. This is because the blade started to ring upon exit and you should make sure to cut off this end.) Set up your cross cut saw on your table saw very square then taking about .030 inches in a pass trim both ends until the ends are clean, square and the piece is exactly 4". Cut another piece to 6+ inches and clean up the ends on the table saw till it is square and 6" long. Measure down the 4" pieces 1" from each end and make a line. Measure from the lip .125" and make a line. Where these lines intersect, use a drill press and drill a #36 hole through to the channel. (Marking the hole with a spotting dril is handy to keep the wholde from drifting. At least make sure you have as little of the drill bit sticking out of the chuck as posible and mark the spot with a punch.) Tap to #6 32 tpi. These will be the plate holder screws. (Note: tap from the small side for a reflection plate holder and from the thick side for a transmission holder, or you can make two slots in the same plate holder.) Mark the two 4" pieces on the ends in the center. (This operation will make the parts "Handed" so make sure to pick opposite ends for this mark.) Drill in a drill press a #F hole about 1/2" deep. Tap to 5/6" 18 tpi. Measure .375" up and over on the 6" pieces (on the 6" face) and make a mark at each end. Drill through with a 5/16" drill bit. (If you miss this hole or the holes in the ends you can make this hole larger so you can get the parts to align.) In the center of the bottom of the 4" pieces (away from the slots) drill a #7 hole .425" deep. Tap with a 1/4 20 tpi tap. In the center of the 6" piece, on the same face as the holes, drill a #7 hole .425 or so deep and tap to 1/4" 20 tpi. These will be the mounting holes. Clean up the corners with a file, and clean up the holes with a countersink tool. Spray paint with Krylon Ultra flat black paint. Bolt channels to the bas with 2-5/16", 18 tpi, 1" long Allen bolts. Put 4 #6 32 tpi Allen bolts into the channels but first file the ends flat with a 6" mill smooth file. The length should be chosen so it sticks out about .25" when holding a plate. Put 3 1/4", 20 tpi, .75" long Allen set screws into the tapped holes. These now will fit any 1/4" mounting rod. Spray paint with Krylon Ultra flat black paint. My total time invested was three hours. A nice touch would be to bevel the front side of the plate holder to 45 deg. You can easily do this with a router and a bearing bit. What you say? Cut aluminum with wood working tools? The truth is it works very well and I have been doing it for years. It works much better than many woods and it is much faster than milling. I once purchased a 9 HP pin router from Boeing that was used to rout airplane parts. We used it to make electric guitar bodies. If you were going to use your table saw a lot for making aluminum parts I would use a ATB grind 60 tooth blade with large blade stiffeners. 92bc01c2d0c8c5892dd007140e1863eb2e77390b 0 834 1718 2013-05-02T00:38:15Z Admin 0 wikitext text/x-wiki == Simple Gravity Base == by Dave Battin {| |- |[[Image:CIMG8817.JPG|right]] Here is an example of gravity bases. They are easy to make and quite stable. The items you need are: *12" steel rod, 1/2" diameter *4" section of 3" or 4" PVC pipe *Plaster of Paris *Scraps of steel or lead *Wooden board *3 round head screws (optional) Assemble the base as follows: * Drill a 1/2" hole through the wooden board to accept the rod nicely. * Clamp the board to a workbench top so the the steel rod can go through the hole and stick up above the board by 3-1/2". * Position the PVC pipe section on the board, over the rod. The rod should be off-center. * Fill the PVC pipe with a combination of Plaster of Paris and scrap metal. The metal provides the weight, so the more the better. Feet can be cut into the PVC as shown in the bases depicted here. The round head screws can be set in the plaster instead, providing something of a kinetic mount capability. After a short setting time the base and rod are pulled out off the board and the base is now complete. Paint after plaster is ''completely dry'', usually a week or two(!). |} == Film Holders == Holding the film or plate stable is a prime requirement for making a hologram. Film holders can be as simple as holding up a glass plate with a couple of magnets. But, it must not be forgotten that the film must be held absolutely stable. Film holder Plans: #[[Machined Film holder]] #[[Angle Iron Film Holder]] == Everyday Items == These are just suggestions and the actual results may vary. It is the responsibility of the user of these suggestions to be safe and use common sense. *Heating pads used with three or more settings allow a variable heating to processing trays. Simply put the heating pad under the tray and turn the pad on to the desired setting. *Black foam board can be used for blocking stray light. The type that is black through and through is best as the edge stays black even when it is cut. This material can also be used for making an iris. *A shutter can be made from most old 8 mm movie cameras. They have a low voltage electric shutter. Remove this unit and set up a circuit with the original voltage of the camera and a switch. *A thick piece of glass, a ¼ inch or thicker, can be used as a beam splitter. Using the thick piece of glass allows a small piece of electric tape to be placed over the secondary reflection off the back of the glass. *Sandwich storage containers can be use as processing trays and storage for the chemistry without having to pour back and forth into a bottle. They come in many sizes and shapes with airtight lids. Store sealed containers with chemistry in a dark, dry, cool place when not being used. *Inner tubes can be used as the dampening mechanism between a holographic table and the support legs. *A slab of granite can be used as a holographic table. *Most old overhead projectors have large front surface mirrors and large Fresnel lenses in them. They can be purchased at yard sales and flee markets for just a few dollars. *Most photocopiers and fax machines have front surface mirrors. *New Jefferson Nickels have a weight of 5 grams and new Lincoln Pennies have a weight of 2.5 grams. Standard paper clips have a weigh of 1 gram. To verify the weight of the paper clips put a nickel on one side of the balance and find 5 paper clips of the same size that equals the nickel. These can be used on a balance for measuring out chemicals. *A hair dryer can be used to dry a piece of holographic film or plate after processing. Drying intensity and heat is variable with very inexpensive dryers. *Polarizers can be found in polarizing sun glasses. These can be used to slightly modify the intensity of throughput laser light by inserting it into the beam path and rotating. They can also be used to relatively compare the polarization of light in different locations. *Two pieces of window pane glass and binder clips can be used to sandwich a piece of holographic film. This will hold the film rigid and flat. *A microwave can be used to heat the Deionized or Distilled water needed for mixing up processing chemistry. But please be careful to keep chemistry contaminated containers separate and secure. One method is to heat the water in a clean container in the microwave and then pour it into the chemistry container for mixing, always keeping the clean container free of any chemicals. *Two parts, fast hardening epoxy is great for securing two pieced of metal without the need for drilling and taping. This also allows the disassembly with just a small sharp blow to one of the pieces. *A pinhole can be made by sandwiching 5 or 10 pieced of aluminum foil together and poking with a pin while the pile is on a hard piece of rubber just coming through to the other side. Each piece of foil will have a slightly different size pinhole. *Automobile windshield wiper blades can be used as a squeegee. If you epoxy two blades to a pair of scissors whereas the two blades meet perpendicular out from the cutting surface of the scissors and when the scissors are closed ¾ of the way, you can squeegee both sides of the film at the same time. For plates this is not necessary and one side can be done at a time with one blade. *Clothes pins strung on a line can be used to hang the film when it dries. After clamping the film at two corners with the pins, clamp two more at the bottom corners to keep the film straight when it dries. *Dishwasher drying agent can be used as Photoflo in the final rinsing bath. Use an agent that does not have fragrant and is preferably clear. *Sodium carbonate can be purchased cheaply as a pH increaser for swimming pools and Spas. *Sodium Bisulfate can be purchased cheaply as a pH decreaser for swimming pools and Spas. *Sulfuric acid can be purchased as Automobile battery acid. Most formulas call for concentrations that are lower then the concentration sold as Auto battery acid. *Sanford Sharpie markers, black, which come in different sizes, are ideal for blackening optics, mounts and anything small you want to reduce reflections on. It is a permanent marker that writes on almost anything. *Paper Mate liquid paper correction is a very nice white paint for painting objects for holography. It dries flat white and diffuses the light very well. [[Category:Equipment]] dcb8e7df62404160d3f5e0eac56d6d00667016f6 0 808 1596 2013-05-02T18:53:57Z Admin 0 wikitext text/x-wiki [[Image:Sandbox_Kit.jpg|right]]The "original" hobbyist's approach to holography was described in the May 1979 issue of ''Physics Education'' as the aptly named ''Sandbox Holography''. Metrologic produced and sold identically named kit. The kit included some holographic film, chemicals for processing the film, and few lenses and mirrors. Not included were the laser (and at the time, that meant a moderately pricey helium-neon gas laser) nor the sandbox. Holography is extremely sensitive to movement, even microscopic movement, during the exposure. In conventional photography, movement will blur the image. With a hologram, since movement would completely alter the interference pattern between the direct and reflected laser light, the image can be lost completely. The sandbox was used to help eliminate vibration. In the late 1970's and early 1980's, the Metrologic Instruments Sandbox Holography kit might have cost you $150(US). A suitable laser, another $400 or so, and by the time you had the sandbox set up, you would be out $600 to $700 in 1980 dollars. For the curious, an updated version of the kit is still available from [http://i-fiberoptics.com/laser-kits-projects-detail.php?id=2140 Industrial Fiber Optics]. Industrial Fiber Optics purchased the educational laser and kit product line from Metrologic Instruments in November 2004. Although the [http://i-fiberoptics.com/pdf/45-733a_manual-revc.pdf Sandbox Holography] manual has details specific to the sandbox kit, it still provides a general introduction to holography for the beginner. == Modern Beginner's Kit == [[Image:Integraf_kit.jpg|right]]Diode lasers, like the ones found in common laser pointers, have completely changed what is needed for a suitable beginner's kit. You still need film and processing chemicals, but your first hologram can be made with no additional lenses or mirrors (because the diode laser beam naturally spreads), and there are some simple techniques developed over the years since the Sandbox kit was first introduced to eliminate the sandbox. In the new era, sandbox holography has evolved into [http://www.holoworld.com/shoebox/ Shoebox Holography], and there are now three, relatively economic ways for novice holographers to begin their hobby. #Buy the ''Shoebox Holography'' book. With that as a guide (or the equivalent information scoured from the Internet) acquire a suitable laser, holographic film, and chemicals and have at it. #Acquire one of the kits available from [http://www.integraf.com/holography_kit.htm Integraf]. (Film is more difficult to work with than glass plates, so the Standard or Student Kit is much preferred over the Budget Kit.) #Acquire a diffent type of kit from [http://www.litiholo.com Litiholo]. For the truly novice holographer, the Litiholo kit is a a bit of an oddity. With it, you can produce your first, interesting hologram. The kit comes with 20 plates, so there is plenty of opportunity for experimentation and the inevitable failure. Be aware, though, it is a self-contained unit. The holographic plates are self-developing, and the configuration is limited to the setups the kit intended. For the mildly curious individual or the elementary school aged child, the Litiholo kit is fabulous. For the slightly experienced holographer, it is good, if for nothing else than the exposure to polymer photo-materials. For the true beginner, though, it is a little like buying a TV dinner because you wanted to learn to cook. There is not enough "participation" to engage the beginner. Of the remaining two choices, simply buying a kit from Integraf saves you all the hassle of acquiring the parts individual. Plus you end up with a higher quality laser than what you would get from laser pointer. Some laser pointers have stability issues that may be unnoticeable in normal use, but disastrous in holography. The information that comes with the Integraf kit, or the identical [http://www.integraf.com/a-simple_holography.htm material available from the Integraf web site], or similar articles online, or from texts like the ''Shoebox Holography'' book, covers what to do next. Not much to it, really. == Beginner's FAQ == ; What is a hologram? : Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ; How little money/bother do I need to make one? : You can make your first hologram with about 2 hours of set up and about $100. ; What is the cheapest way to make a hologram? : [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ; Are the chemicals dangerous? : While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ; What sort of time commitment is there for making a hologram? : You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ; When can I have the lights 'on' during the procedure of making a hologram? : Once the emulsion has become insensitive to to light. For silver-halide holograms this is after the hologram is bleached. For dichromated gelatin holograms this is after the fixing and rinsing steps. ; What are the different kinds of holograms? : [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ; What is the single most important factor when making a hologram? : ''Stability!'' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ; How Does a LASER work? : For a simple introduction to lasers read [[How Do LASERs work?]]. ; Can I use a cheap red laser pointer to make holograms? : Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ; Can I use a Green Laser Pointer to make holograms? : So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ; Where are the Reference and Object beams in a Single Beam Reflection Hologram? : Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ; Some uses for [[Everyday Items]] in holography : Click here for [[Everyday Items]] that can save you money in holography! ; What is a [[Scratch-O-Gram]]? : A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and focusing it from a curved scratch to a point. ; What Books are Available for Holography? : See the [[Books]] section. [[Category:Beginner]] 46e5a56724df3308f69473de9a73e22fb71a28a6 0 848 1812 2013-05-03T01:56:00Z Admin 0 Created page with "by Dinesh Padiyar Silver Halide is the most common holographic material currently used by everyone from hobbyists to professional scientists. This is because of its high sensiti…" wikitext text/x-wiki by Dinesh Padiyar Silver Halide is the most common holographic material currently used by everyone from hobbyists to professional scientists. This is because of its high sensitivity and the fact that it’s easily available commercially. Silver Halide is a salt of Silver and a Halide, which are a group of elements that include Fluorine, Chlorine, Bromine and Iodine, which are light sensitive. The first, accidental, discovery of the light sensitive properties of Silver salts came in 1727 when J Schulze mixed chalk, Nitric acid and Silver in a flask. He noticed that the side of the flask turned toward the sun turned dark. The first deliberate application of this effect, a photograph of a scene, was carried out by Niepce in 1827. This was a long exposure of about 8 hours. In 1841 Henry Fox Talbot patented a “calotype” process which made a permanent negative image on paper soaked in Silver Chloride. The present day emulsion was created by Richard Leach Maddox, who proposed using gelatin and Silver Bromide in what he called the “dry plate process”. Shortly after that Eastman Kodak coated a flexible film with this as a thin emulsion, mass produced it, and launched large scale photography. Silver Bromide is only sensitive in the UV and blue regions and so dyes need to be added to it in order to make it sensitive to other colors. In holography, specific dyes are added to give the emulsion a high sensitivity at particular, commonly available laser lines. Commercial SilverHalide materials consist of crystals, or ''grains'', of Silver Halide dispersed in a layer of gelatin, each grain consisting of many thousands of molecules of Silver Halide. When exposed to light individual molecules of Silver Halide on those grains that were illuminated break down to Silver which, due to it’s small size, appears black. Since the number of molecules of Silver Halide that convert to Silver on any one grain depends on the intensity of light hitting the grain, the darkness, or density, of any one grain depends on the light hitting it. Thus the emulsion converts the variation of light that hits it, the ''exposure'', to a density variation. After exposure the emulsion consists of exposed and unexposed Silver Halide grains. The action of converting the exposed emulsion to the same variation of density as the variation of light intensity at exposure by amplifying the exposed grains of Silver Halide is known as ''processing''. The removal of the unexposed grains is known as ''fixing''. Thus the entire process consists of exposure, development and fixing. There is also a bleaching step that is no longer widely used in photography but is common in holography. The fixing step is sometimes omitted. == Exposure == The exposure of an emulsion refers to the total amount of light energy that has hit it over a given period of time, the ''exposure time''. In holography, this is referred to as the ''sensitivity'' or ''speed'' of the emulsion and is given in terms of Joules/sq meter. However, due to the extremely high sensitivity of Silver Halide emulsions, this is usually given as microjoules/sq cm. This is the amount of energy necessary in order to produce a certain variation of darkness in the emulsion that faithfully maps the light that hit it. Too much exposure and the entire film goes black, too little and there is little or no variation of darkness. Factors important for exposure are the ''resolving power'' of the film and the contrast. The resolving power of a film determines the smallest detail that the film can captured. In holography, these details are in the order of a micron and so holographic film needs to have a very high resolving power. This resolving power depends on the size and distribution of the individual grains in the emulsion, referred to as the ''granularity''. In photographic film, the size of the grains may be about a micron whereas in holography it’s usually about 50 nanometers. As the grains get smaller, the sensitivity decreases, i.e. it takes a longer exposure time to create the same density variation. Another factor that affects resolving power is the ''scattering'' within the emulsion. This refers to the fact that the light entering the emulsion is scattered into random directions by the grains themselves. This randomly scattered light will affect nearby grains and so will decrease the resolving power. A measure of this resolving power is given by a curve plotting density against the logarithm of the exposure, known as the Hurter and Driffield, or H&D curve. The slope of this curve is known as the ''gamma''. Typical values of gamma for standard photography are about 0.7 while high contrast film has a gamma of about 1.5. In holography, it is necessary to have a gamma of at least 2. After exposure, the emulsion contains an invisible image called the ''latent image'' in which some of the grains in the emulsion were exposed to light and some were not. These exposed, latent image grains are distinguished from non-exposed grains by the their ability to be reduced to elemental Silver by the developer. == Development == All the grains in the emulsion consist largely of Silver Bromide with a few atoms of free, elemental Silver, called ''sensitivity specks''. These Silver specks contain about 1/10,000,000 of the mass of the whole grain. When a particular grain is exposed to light, some of the Silver specks on it are ionised by the release an electron. These Silver ions cause neighbouring Silver from nearby Silver Bromide molecules on the grain to also reduce to elemental Silver and hence the speck grows to form a larger latent image-speck. When the speck has grown to a particular size, it provides a point at which the developer can attack the grain. Grains which have not been exposed to light will still have specks, but with no ionisation of the specks, they will not grow sufficiently to form development centres. Developers consist of the following components: ; Developing agent : The developing agent is responsible for the reduction of all the Silver Bromide in the entire exposed grain into Silver, these grains being differentiated from the unexposed ones due to the presence of latent image specks. This results in an enormous amplification of the latent image by a factor of about 10,000,000. This is due to the fact that the mass of Silver in the original, undeveloped latent image speck was only about 1/10,000,000 th of the mass of the grain. Development causes the entire grain to convert to Silver. The developing agent is an organic reducing agent with a benzene ring-type structure. ; Preservative : Developing agents tend to oxidize rapidly when exposed to air making them ineffective. To prevent this, a preservative is added. Usually this is Sodium Sulphite but sometimes Potassium Sulphite is used. As the sulphite concentration is increased, the developer lasts a longer time. However, if too much sulphite is added, the emulsion may fog. ; Accelerator : Developing agents only work when they are alkaline, with increasing activity as the alkalinity increases. An accelerator is an alkaline compound that activates and accelerates the developing action. The accelerators are classed as strong, medium and weak. The stronger the accelerator, the more rapid the development while weak accelerators tend to balance out contrast. Strong accelerators include hydroxides, such as Potassium Hydroxide, medium accelerators include Carbonates, such as Sodium Carbonate. ; Restrainer or Anti-foggant : Some developers tend to attack unexposed grains which causes fog in the emulsion. To prevent this an antifoggant, or restrainer, is added. The most common restrainer is Sodium Bromide. Some low alkalinity developers may not need restrainers. == Fixing == After development the emulsion consists of grains of Silver, formed by the reduction of exposed Silver Halide, and unexposed Silver Halide grains. Fixing removes these unexposed Silver Halide grains rendering the emulsion inert to further reactions from light. The fixer is a solution of Sodium Thiosulphate which converts the Silver Bromide into Silver Thiosulphate and a few other ions. Ammonium is used in place of Silver in Rapid Fix due to the stronger solvent action. Of Ammonium Thiosulphate. The Silver Thiosulphate is very soluble in water and washes out of the emulsion and into the fixing bath. However, if the concentration of the Silver ions in the fixing bath is too high other, less soluble, Silver salts are formed. These can cause a yellowing of the emulsion. Commercial fixers also include a weak acid, usually acetic acid, to stop the action of the developer. The pH of the fixer is then about 4 or 5. If the pH decreases to too low a value (ie it becomes too acidic), the acid attacks the Thiosulphate and releases free Sulphur, This free sulphur forms a suspension in the emulsion causing it to fog. A hardener is sometimes also added to prevent swelling and softening of the gelatin during the wash. This is accomplished by lowering the pH of the fixer by a suitable agent to a value of about 3. == Bleaching == Bleaching is the action of an oxidising agent on the Silver grains. The oxidising agent oxidises the Silver to a soluble salt, that can be washed. The purpose of bleaching a hologram is transform the reconstruction method of the hologram from one whose primary reconstruction method is by altering the intensity of the reconstruction light - known as an ''amplitude hologram'' - to one whose primary reconstruction method is by altering the phase of the reconstructing light - known as a ''phase hologram''. In the former, amplitude-type hologram, the intensity of the (uniform) reconstructing beam is decreased as it passes through various parts of the hologram by an amount depending on how dark that particular part of the hologram is. The image is therefore dependent on the variations of the intensity of the reconstruction beam which is a map of the darkness variation of the plate. In the phase-type hologram, the hologram is completely transparent but either its thickness or its density varies at different points of the holographic medium thus altering the refractive index at that particular point. This variation of index alters the optical light path of the reconstruction beam as it passes through different parts of the holographic medium. In practice no hologram is ever completely of one or the other type, but a mixture of the two. This variation of index in a medium is known as ''phase variation''. It has been shown that the brightness, or ''diffraction efficiency'', of an amplitude hologram cannot exceed 33% while a phase hologram can be 100% efficient. However when a Silver Halide hologram is developed it is, by default, an amplitude hologram, due to the fact that the developer’s action varies the density of the medium. It would therefore be advantageous to convert the amplitude hologram to a phase hologram. This is done by a bleach which makes the entire holographic medium transparent and transforms the density variations of the medium into index variations. There are essentially two types of bleaches - reversal and rehalogenating. In reversal bleaches, the exposed, Silver grains are converted into a soluble complex and washed out in the bleach bath leaving the unexposed Silver Halide grains left in the emulsion to carry the holographic image. In this case, it’s necessary not to fix the hologram after developing since the loss of the unexposed Silver Halide would leave nothing in the emulsion. A reversal bleach bath consists of an oxidising agent , a buffer and sometimes other additives such as dyes. In rehalogenating bleaches, the reduced Silver grains are re-converted back to Silver Halide. Rehalogenated bleaching can be carried out on either fixed or unfixed holograms. In the fixed rehalogenating case, the unexposed Silver Halide is fixed out and the rehalogenating bleach converts the exposed Silver back to Silver Halide. In unfixed rehalogenation, the unexposed Silver Halide grains are still present after the bleach converts exposed Silver grains to Silver Halide grains. The difference between the two, necessary to distinguish image from non-image, comes from the fact that rehalogenated Silver Halide grains are larger than the original unexposed Silver Halide grains. One consequence of the increased size of the grain is that there is an increase in noise since scattering is dependent on, and increases with, larger grain sizes. A rehalogenating bleach bath consists of an oxidising agent, an alkali halide, a buffer and sometimes dyes. == References == ''Silver-Halide Recording Materials'' H. I. Bjelkhagen ''Topics in Applied Physics'', vol 20. "Holographic Recording Materials" ed H. M. Smith 9dda31099133859815176255809ea3f1774a68e3 0 270 1706 388 2013-05-03T02:01:46Z Admin 0 wikitext text/x-wiki [[Image:CIEDiagram.jpg]] Holograms need a material to record interference fringes. There are many materials that can record fringes. ; [[Silver Halide Materials]] : Basic information about silver halide holographic plates and film. ; [[Silver Halide Chemistry]] : Theory and Practice of Making Silver Halide Plates and Development. ; [[Silver Film Comparison Chart]] : A quick comparison of the qualities of different commercially made films. ; [[Dichromated Gelatin Chemistry]] : Theory and Practice of DCG Plates and Development. ; [[Polymer Film and Processes]] : Many commercially sold holograms are made from photopolymers. ; [[Photoresist]] : Taken from the electronics industry, this material can make relief holograms for embossing. ; [[Coating Methods]] : Coating Gelatin on to a glass plate is an art in itself. ; [[Crystals]] : There are many crystals that can record an image. The cost and exposure energy required is very high so they are not often used for holography. ; [[Embossed Holograms]] : These are like the holograms seen on credit cards. ; [[Gelatin]] : Used as the suspension medium to hold light sensitive particles. ; [http://en.wikipedia.org/wiki/Hologram#Materials Wikipedia] : Wikipedia's summary of Holographic Recording Materials. ; [http://en.wikipedia.org/wiki/Periodic_table_%28standard%29 The Elements] : The Periodic Table of the Elements ; [[Books]] 43b6f377568a8bf9b1db03dc14f6630a1ee8a596 0 271 1708 390 2013-05-03T03:48:44Z Admin 0 /* True Color Holograms */ wikitext text/x-wiki See [[Setups]] for more information on making these types of holograms. ===A Hologram Defined=== hol·o·gram (hŏl'ə-grăm', hō'lə-) n. A [[Diffraction|Diffraction Pattern]] which, when properly lit, produces a three-dimensional image. Typically, holograms are made using a laser as a light source and and a very high resolution film or glass plate to record the diffraction pattern resulting from interference between light coming directly from the laser and light reflected from the object. ===Transmission hologram=== This was the one of the first holograms made. A transmission hologram is made when the reference beam and light from the object enter the recording material from the same side. The recorded interference fringes form a transmission grating which diffracts light passing through the hologram. Properties include: * looks like a blurry rainbow image when viewed with white light * viewable as a sharp image only by shining laser light through the hologram * recording material requirements are more relaxed (less resolving power is needed) * simple set-up * greater depth of the scene is possible * the scene can be projected by shining a collimated laser beam through the hologram ===Reflection hologram=== A reflection hologram is made when the reference beam and light from the object enter the recording material from opposite sides. Properties include: * viewable in regular light * very simple Denisyuk style setup can be used * finished hologram is monochromatic (a single color) for each laser color used * color can be shifted by pre or post shrink/expanding recording material ===H1 to H2 copies=== H1 refers to a first generation (master) hologram. H2 refers to a copy made from the H1. H1s are usually transmission holograms and H2s are usually reflection. They may use different recording materials. Properties include: * Somewhat complex setup requirements * Objects can be made to appear to be coming out of the plate towards the observer * Once a usable master H1 is made and the setup constructed, many copies can be produced easily ===Rainbow Holograms=== Rainbow holograms are transmission holograms which are produced in such a way as to be viewable in regular white light. Depending on the viewing angle, the color changes (hence the term rainbow) Properties include: * perspective information is lost in one axis (for example, you may not be able see a change in perspective when looking from above or below) ===Open-Aperture Transmission Hologram=== An open-aperture transmission hologram is simply a transmission hologram the has the image very close to the film plane and is designed to be viewed in white light. Properties include: *White light viewable. *Image blurs colors as the image move in front of, or behind the film plain. *2 cm usable depth of field. *The image is achromatic. ===Multiplexed holograms=== Multiplexed holograms store many different holograms on one piece of film usually as multiple exposures. Properties include: * simple animations are possible * diminishing quality as more holograms are stored ===Edge Lit Holograms=== Edge Lit Holograms have the reference beam entering the plate from one edge instead of one face. This allows the illumination to remain hidden from the observer and makes for a fairly compact display. *They are difficult to make. [http://www.media.mit.edu/spi/SPIPapers/ryder/thesis.pdf Edgelit holography:Extending Size and Color] by Ryder Sean Nesbitt ===Embossed Holograms=== Embossed holograms are made by forming a rainbow transmission hologram in thermoplastic and bonding it to a mylar mirror. It is the kind of hologram seen on credit cards. Properties include: * very low per-unit cost when mass-produced * shallow hologram depth (usually just a few millimeters) * durable and flexible * mass production can use existing equipment and technology (e.g. CD production) ===Pulsed Holograms=== Pulsed Holograms can be either transmission or reflection. The key difference is the pulsed laser emits a short, powerful pulse of light rather than a continuous beam. This pulse (about 20ns) is short enough to stop moving objects and make an image. Even bullets can be stopped with the correct setup. Most often used for portraits. * The flash photography of holography * Stability requirements are greatly diminished, allowing for holograms of people, melting ice, flowers, animals, etc. to be made * Pulse lasers are very expensive * Setup and testing can be tricky and dangerous See [[Tips for Pulsed Ruby Holograms]]. ===True Color Holograms=== [[Image:CIEDiagram.jpg]] True color holograms are a variety of reflection hologram made with more than one laser color. There have been good true-color holograms made with two, three and four colors of lasers. The resulting hologram displays the same colors as the original object. * Since true color holograms are multiplexed holograms, recording material need to be capable of holding a lot of information * Lasers and equipment can be expensive and tricky to set up [http://www.ultimate-holography.com See examples by Yves Gentet] b33d8a2a0c533558968017cb25337aa9077b7c18 0 821 1652 2013-05-04T01:03:31Z Admin 0 Created page with "'''Diffusion method - estimated cost'''<br>November 18 2002 at 6:53 AM As promise, I post my estimated costs table for a batch of 20 holoplates made with the Jeff Blyth's diffus…" wikitext text/x-wiki '''Diffusion method - estimated cost'''<br>November 18 2002 at 6:53 AM As promise, I post my estimated costs table for a batch of 20 holoplates made with the Jeff Blyth's diffusion method. Silane, LiBr, Pinacyanol come from Sigma-Aldrich. All prices are in November 2002 Euros (1 Euro ~ 0,97 USD) {| style="wikitable" border="1" |- | Chemical | Price/Quantity | Diluted quantity | Quant/20 plates | Price/20 plates |- | AgNO3 (6%) | 18,11/10g. | 166 ml | 60 | 6,55 |- | LiBr (3%) | 11,2/100g. | 3300 ml | 300(*) | 1,02 |- | Pinacyanol (0,1%) | 16,81/250mg | 250 ml | 7,5 | 0,5 |- | Ascobic Acid (1%) | 2,11/30g | 3000 ml | 300(*) | 0,21 |- | Gelatin (15%) | 9/1000g | 6666 ml | 100 | 0,14 |- | Chrome Alum (2%) | 3/100g. | 5000 ml | 300(*) | 0,18 |- | Silane (1%) | 31,16/100ml | 10000 ml | 100 | 0,31 |- | Glass (4x5) | 12,5/20 | - | 20 | 12,50 |- | Total for 20 plates | - | - | - | 21,41 or 1,07/plate |} (*) I assume I change for each batch * LiBr + Dye bath * Chrome Alum hardener * Ascorbic Acid sensitizer But please pay attention of this following note from Jeff about the LiBr bath: "Please note that I myself reuse the dye/LiBr baths several times. A little bit of precipitate in the bottom of container (it is only AgBr) can be left there and the liquid poured off or the solution just filtered. So you can make many plates if you want to for the initial expence. The quantity of subbed plates you could make is enough for an industrial production run!" I don't calculate price for water, acetone and methanol because those products are cheap. First batch can seems expensive because you need to purchase relatively big quantity in regard of the used quantity and you need to some laboratory material. Hope this can give you the curiosity to test this easy method. Jean PS: my 2nd batch has failed because I don't care to dry plates enough after Chrome Alum bath! Results was presence of chrome salt who fog the plates. I'll try hardening gelatin with a bath of 1% formalin in DI water. f40d5afa50dcb94445ae52d04dcd760813bd3ae4 0 226 1674 300 2013-05-04T01:08:35Z Admin 0 wikitext text/x-wiki There is a great deal of equipment available for use in holography. While a hologram can be made with very simple equipment, many holographers have $1000s invested into there labs. The most important piece of equipment is the [[Laser|Laser]]. It privides the coherent light source required for making a hologram. In order to steer and shape the beam holographers use [[Mirror|Mirror]]s, [[Lens|Lens]]es and [[Diffuser|Diffuser]]s. More advanced holography is done with 'split beams'. This involves taking the laser beam in splitting it into two or more beams with a [[Beam Splitter|Beam Splitter]]. A hologram is recorded on a medium. [[Silver Film Comparison Chart|Silver Halide Film]] and [[Dichromated Gelatin Chemistry|Dichromated Gelatin Chemistry]] are the most common mediums for amature holographers and art holographs. Comercial holograms are usually [[Embossed Holograms|Embossed Holograms]] or [[Polymer Film and Processes|Polymer Film and Processes]]. Other exotic materials can record a holographic image. See [[Hologram Recording Materials|Hologram Recording Materials]]. The stability of film is of the upmost importance to recording a hologram. [[Homemade Equipment#Film_Holders|Film Holders]] are designed to hold film stable to 1/2 wavelength of light for the entire exposure time (or better). The polarization of a laser beam can be rotated with a [[Wave Plate|Wave Plate]] and this can be quite useful in a large set up. Every optic will contribute noise to the laser beam. [[Optics Aberrations|Optics Aberrations]], dust and fingerprints will leave a mark on the beam quality. In order to clean the beam a [[Spatial Filter|Spatial Filter]] is used. All of the optics past the first [[Beam Splitter|Beam Splitter]] need to be held perfectly still. This is acoumplished by designing a [[Optical Bench|Optical Bench]] and [[Optic Mounts|Optic Mounts]] that are very rigid and have no resonances. The exposure time is calculated by using a [[Light Meter|Light Meter]]. Also the ratio of reference to object beam is measured with a [[Light Meter|Light Meter]]. In order to adjust the exposure energy a [[Shutter|Shutter]] is used to turn the beam on and off. A [[Shutter|Shutter]] can be as simple as a black card removed from the beam by hand or a computer controlled device === Fringe Lockers === [[Fringe Locker|Fringe Locker]]s === Beam Blocking === [[Beam Blocker|Beam Blocker]]s === Neutral Density Filter === [[Neutral Density Filter|Neutral Density Filter]] e3b34101a384e66bff6aed3bdd19af6116895ec2 0 501 1808 1153 2013-05-04T01:09:41Z Admin 0 wikitext text/x-wiki Silver Halide is one of the most popular recording materials. The historical and available commercially available films properties are listed here: *[[Silver Film Comparison Chart|Silver Halide Film]] *[[DIY Silver Halide Film]] *[[Silver Halide Processing Chemistry]] *[[Silver Halide Film vs Chemistry vs Hologram Type]] *[[Silver Halide Sensitized Gelatin]] SHSG *[[Index Matching]] *[[Pre-Swelling]] *[[Post-Swelling]] *[[Squeegee Technique]] *[[Fringe Photos]] *[[Painting Holograms]] *[[Exposure Tests]] *[[Hardening Holograms to Fix the Color]] *[[Psuedocolor Processing]] *[[Laminating Film to Glass]] fcc77273ced90c3cb2fc0d7b0d27876f4f1ea0d7 0 851 1828 2013-05-05T03:27:51Z Admin 0 wikitext text/x-wiki == CW Developers == CW developers are allegedly suitable for exposures with continuous wave lasers (as opposed to pulsed lasers). The CW-C2 developer is named for its inventors Cooke and Ward, not its use with CW lasers. It debuted in the March, 1984 issue of ''Applied Optics'' in an article authored by D. J. Cooke and A. A. Ward. Note that the JD-2 and JD-3 chemistry use the same exact developer, and that it is closely related to the CW-C2 developer, using 25% less urea, but otherwise the same. {| border="1" ! !'''''CW-C2''''' !'''''JD-2/3''''' !'''''Pyrochrome''''' !'''''Pyrochrome plus''''' |- | align="center" | '''Part A:''' || || || || |- |Metol || align="center" | || align="center" | || align="center" | || align="center" | |- |Pyrogallol || align="center" | || align="center" | || align="center" | 10 g || align="center" | 20 g |- |Catechol || align="center" |20 g || align="center" |20 g || align="center" | || align="center" | |- |Ascorbic acid || align="center" |10 g || align="center" |10 g || align="center" | || align="center" | |- |Sodium sulfite || align="center" |10 g || align="center" |10 g || align="center" | || align="center" | |- |Potassium metabisulfite || align="center" | || align="center" | || align="center" | || align="center" | 30 g |- |Urea || align="center" |100 g|| align="center" | 75 g || align="center" | || align="center" | |- |Water || align="center" | 1000 ml || align="center" | 1000 ml || align="center" | 1000 ml || align="center" | 1000 ml |- | align="center" | '''Part B:''' || || || || |- |Sodium carbonate || align="center" | 60 g || align="center" | 60 g || align="center" | 60 g || align="center" | 130 g |- |Water || align="center" | 1000 ml || align="center" | 1000 ml || align="center" | 1000 ml || align="center" | 1000 ml |- | align="center" | '''Working solution:''' || || || || |- |Mix A + B + water || align="center" | 1 + 1 + 0 || align="center" | 1 + 1 + 0 || align="center" | 1 + 1 + 0 || align="center" | 1 + 1 + 0 |- |Development time || align="center" | 2 min a 20 C || align="center" | 2 min at 20 C || align="center" | 2 min at 20 C || align="center" | 2 min at 20C |- |Hologram type || align="center" | Reflection || align="center" | Reflection || align="center" | Reflection || align="center" | Reflection |} bdedb3ee9bbdbf8f27a04f3b158be61b8c4ed95e 0 507 1814 1165 2013-05-05T03:37:44Z Admin 0 /* JD-4 */ wikitext text/x-wiki This is a collection of chemistries for holographic development and holographic film manufacture. For the definitive source about holographic development please purchase a copy of SILVER HALIDE MATERIALS FOR HOLOGRAPHY AND THEIR PROCESSING by Hans Bjelkhagen ISBN 3-540-58619-9. Contact Integraf for JD-2, JD-3, JD-4, SILVER HALIDE MATERIALS AND THEIR PROCESSING by Hans Bjelkhagen or for Slavich Film. Many of these chemicals are very dangerous. Please don't breath the dust or fumes. Make sure to wear gloves and don't pour the used chemicals in your drain. Your drain goes to someone's drinking water! Don't forget to read and follow the MSDS. ---- Notes on Mixing Chemistry for Silver Halide Materials The order and methods you use for mixing is very important. Normally you add in the order of the formulation. Some of these formulations are likely to be out of order. ---- =TJ1= [[TJ1 Developer]] - By Jeff Blyth =JD-2= from Integraf for PFG-01 from Slavich Solution A *Distilled Water 100 Deg. F 750 ml *Catachol 20 grams *Ascorbic Acid 10 grams *Sodium Sulfite 10 grams *Urea 75 grams *Water 68 Deg. F 1 liter Solution B *Distilled Water 100 Deg. F 800 ml *Sodium Carbonate, Anhyd. 60 grams *Water 68 Deg. F to make 1 liter Mix equal parts A and B just before development. Mix enough for one hologram only. (I have developed 3, but the first one is best) Bleach *Distilled Water 68 deg. F 750 ml *Potassium Dichromate 5 grams *Sodium Bisulfate 80 grams *Water 68 deg. F to make 1 liter Dissolve potassium dichromate completely before adding sodium bisulfate. The bleach can be used for a long time. At least 5 months shelf life. *Develop 2 minutes *Rinse 3 minutes *Bleach till clear (less than two minutes) *Rinse *Photo flo *Air dry =JD-3= from Integraf Developer Part A *Water 750ml *Catechol 20g *Ascorbic acid 10g *Sodium sulfite 10g *Urea 75g *Water to make 1L Part B *Water 750ml *Sodium carbonate 60g *Water to make 1L Bleach *Water 750ml *Copper sulfate 17g *Potassium bromide 55g *Succinic acid 2g *Water to make 1L Post Treatment *Water 300ml *Ascorbic acid 10g *Water to make 400ml Mix equal parta A and B. Working solution has a life of 8 hours. Only develop one hologram. Develop for 2 minutes with agitation. Soak in distilled water for 10 seconds. Wash for 3 minutes. Do not dilute bleach. Bleach emulsion side down till clear. Less than 2 minutes. Wash for 3 minutes. Dilute post treatment 1 to 10 with water. soak under bright light until the hologram turns from pink to light brown. Wash for 3 minutes. =JD-4= from Integraf for PFG-03M from Slavich Developer Part A (1 liter) *Metol or Elon (p-Methylaminophenol sulfate) 4 g *Ascorbic acid (powder) 25 g Developer Part B (1 liter) *Sodium carbonate, anhydrous 70 g *Sodium hydroxide 15 g Bleach (1 liter) *Copper sulfate (pentahydrate) 35g *Potassium bromide 100g *Sodium hydrogen sulfate crystals 5g Mixing instructions <br>Use three l liter (or larger) size clean glass or plastic bottles with leak proof caps. Label them A, B, and Bleach respectively. Warm the distilled or de-ionized water to about 40o C (warm to the touch). Fill the bottle marked A with 700 ml of warm water. Dissolve the Metol in it, then add the ascorbic acid. Add 300 ml of warm water to make 1 liter of Part A developer. Tightly cap the bottle. Part A will oxidized if it is exposed to oxygen. In time (over a few days to few weeks), the solution may turn yellow due to the oxidation of ascorbic acid; the solution is still useable. Once the solution turns dark brown, the potency is lost and should be disposed. One way of protecting it from oxidation is to subdivide the solution into smaller bottles so that the unused portions are in fully capped bottles, with little or no air space on top. Refrigeration also slows down oxidation (exercise extreme caution to prevent its mistaken identity as food). Follow the same procedure for Part B (add the sodium carbonate and sodium hydroxide in either order). This solution will keep for many weeks. Follow the same procedure for mixing the Bleach. This solution has very long shelf life. =Hardener - Slavich= *Formalin 37% *10ml Potassium Bromide *2g Sodium Carbonate *5g Water to 1L =Fixer - Slavich= *Methyl Phenidone 0.2g *Hydroquinone 5g *Sodium Sulphite(Anhyd.) 100g *Potassium Hydroxide 5g *Ammonium Thiocyanate 12g *Water to 1L =Metol-Ascorbate developer= courtesy of Laser Reflections The formula is as follows: Metol-Acorbate Developer (Part A + Part B) Part A: *Metol 10g *Ascorbic Acid 80g *Water to 1000ml Part B: *Sodium Carbonate Anhydrous 120g *Sodium Hydroxide 14g *Potassium Bromide 4g *Water to 1000ml Use it in combination with a Fe-EDTA bleach - a safe, stable bleach which has a long shelf life. =Fe-EDTA Bleach= *EDTA (2Na) 30g *Fe(III) Sulfate 30g *Potassium Bromide 30g *Sodium Hydrogen Sulfate Crystals 30g *Water to 1000ml =Russian Emulsion Tips= From Jeffrey: When using Russian emulsions - Pre-develop gelatin hardening bath - Sensitizes and maintains colors, allows squeegee use *Distilled water 750 ml *Formaldehyde 37% (Formalin) 10 ml (10.2 g) *Potassium bromide 2 g *Sodium carbonate (anhydrous) 5 g *add distilled water to make 1 L Processing time 6 minutes. Developing times may increase with harder gelatin. =CWC2= From Jeffrey: CWC2 DEVELOPER and PBU-AMIDOL BLEACH - for all types of HOLOGRAMS CWC2 - two-part DEVELOPER PART A solution *500 ml. warmed distilled water. *(Pyro)Catechol 10 grams *L-Ascorbic Acid (Vitamin C) 5 grams *Sodium Sulfite (anhydrous) 5 grams *Urea 30 grams PART B solution *500 ml. warmed distilled water. *Sodium Carbonate 30 grams Part A is good for one month, Part B indefinitely. Add equal parts A & B to activate just a minute or two before use, just enough to cover one hologram. Mixed solution is active for 20 minutes. Discard after one use to assure each hologram has optimum development. Develop time:at least TWO minutes @ 68 degrees F. with constant agitation (AGFA). FIVE minutes for low power lasers, for HRT plates and PFG-03M plates. Rinse in distilled water. View a green safelight through rinsed plate to judge density - some variation is OK. Adjust exposure/developing time to achieve a final developed density of: *D 1.5 - 2 - medium gray (for an unbleached transmission hologram) *D 2 - 3.5 - very dark (reflection holograms). *D 4 - appears mostly opaque (good for HRT reflection holograms). Do not use fixer if it will be bleached (reflection holograms are usually bleached). Notes on developed density - this stage is where you figure if exposure, ratio, gleam spots, beam centering, even illumination, and overall light levels and their recorded patterns are OK for the next shot as well, or need adjustment. After the plate is bleached clear, these clues are gone. Although dark, wet, and hard to see, observation of different gray levels is important, hopefully understanding what caused each visible pattern. A good safelight is important. My favorite is a commercially available four-foot fluorescent fixture with plastic tube filters. =PBU-AMIDOL re-halogenating BLEACH= (Phillips Bjelkhagen Ultimate) *Potassium Persulfate 10 grams *Sodium Bisulfate (or Citric Acid) 10 grams *Potassium Bromide 20 grams *Cupric Bromide 1 gram *Amidol (- add last ! -) 1 gram Mix one at a time, in sequence, into 500 ml. warmed distilled water, then add another 500 ml. distilled water to make 1 liter. *Wait at least 30 minutes for chemical activation. *Bleach unfixed plate for 3-5 minutes @ 68 degrees F. 'til clear + 2 minutes. Rehalogenating (and image brightening) continues after clearing. *Rinse, rinse, rinse in distilled water. *With a drop of Photo-Flo in the final rinse, squeegee. *Air dry, a low-heat blower or drying cabinet for around 15 minutes - not too fast, not too slow. An acetic acid rinse after bleaching may help reduce print-out (the emulsion will darken a bit after you run out in the daylight to see your image). I prefer to avoid intense sunlight until aged a few days. Re-bleaching later will partially clear a darkened plate and give some immunity to further print-out. Bleach can be re-used a few times, and is usually good for two weeks - red color will fade to clear, indicating exhaustion. *Beware sediment as it ages - do NOT attempt to re-mix before each use - decant and do not dump dregs out onto emulsion. *Bleach will leave permanent purple stains on everything - handle carefully ! Many thanks to Cooke and Ward, Hans Bjelkhagen, Nick Phillips and Ed Wesly for the many trials to attain the basic formulation. -------------------------------------------------------------------------------- =GP-9= *Phenidone .026 g *Hydroquinone .665 g *Anhydrous Sodium Sulfite 13 g *Potassium Hydroxide 1.38 g *Ammonium Thiocyanate 3.12g *Distilled Water 1 L =GP-61= Transmission *Distilled Water 700cc *Metol 6 g *Hydroquinone 7 g *Phenidone .8g *anhydrous sodium Sulfite 30g *Anhydrous Sodium Carbonate 60 g *Potassium Bromide 2 g *Sequesterine Agent 1 g *Water to make 1 L =GP-62= Reflection (use Bleach) Part A *Distilled Water 700 cc *Metol 15 g *Pyrogallol 7 g *Anhydrous Sodium Sulfite 20 g *Potassium Bromide 4 g *Sequestrene Agent 2 g *Water to make 1 L Part B *Distilled Water 700 cc *Anhydrous Carbonate 60 g *Water to make 1 L =Kodak D-8= *Ascorbic Acid 18g *Sodium Hydroxide 12 g *Sodium Phosphate Dibasic 28.4 g *Distilled water 1 L Just before use add Phenidone .5 g =Transmission bleach= *Water 1 L *Potassium Ferocyanide 1 tablespoon *Potassium Bromide 1 tablespoon (or Cupric Bromide 1 tablespoon) =Reflection bleach= *water 1 L *potassium Bromide 30 g *Borax 15 g *Potassium dichromate 2 g Just before use add PBQ (p-benzoquinone) 2 g (good for 15 minutes) =PBQ= *Water 1 L *Mercuric Chloride 1 tablespoon *Potassium Bromide 1 tablespoon or *Water 1 L *Potassium Bromide 30 g *Boric Acid 1.5 g *PBQ 2 g Good for only 15 minutes! or *Sulphric acid 1 g *potassium Bromide 5g *Methyl Paraben 2g *Hydrogen Peroxide 4 g (you have to figure the weight of the Hydrogen peroxide in you solution!) *Potassium Alum 5g (hardener) *PBQ 1 g *Phenosafranine 1g (desensitizer) =GP-431 Bleach = *Water 600 cc *Ferric Nitrate 8-hydrate 150 g *Potassium Bromide 30 g *Dissolve .3 g of Phenosafranine in 250 cc of methanol and then add. *Water to make 1 L Dilute 4 parts water to 1 part gp-431 before use. =Leroy= by Martin Since some are interested in the old Leroy paper, here is my - rudimentary - translation: Excerpts from: M.N. Leroy, Préparation et sensitométrie de plaques photographiques à grain très fin (plaques pour la photographie interférentielle), Paris 1929 ==== Summary ==== The following note presents a new way for the making of fine grain photographic emulsions, derived from colloidal silver, that allows for the spectral recording of remarkable brightness, comparable to Lippmann emulsions. It (the note) summarizes certain results achieved with silver chloride, bromide and iodide. The study of the density graphs indicates a maximum sensitivity at a particular lambda for each of the three cases and depends on the molecular weight of the specific salt used. Having established the characteristic graph of each emulsion at certain spectral levels, the author is studying the variation of gamma as a function of lambda, and points out that these plates, (though) having the qualities of any common plates, they can be sensitized to any wavelength and t can be used for color photography. The present study tried to establish the sensitometric characteristics of Lippmann plates, prepared according the formula of the ingenious inventor of the only direct recording method of color photographs. The results indicated too many variations and lacked the desired consistency. This is certainly due to fluctuations usually occurring (even) with the same composition (differing but on agitation, temperature, filtering, washing etc.). In one case, instead of being sensitive to the wavelength showing the strongest diffraction, we even observed sensitivity to radiation all over the visible spectrum. Without adding any sensitizers, it all the same behaved like an orthochromatic plate and, this was consistent for all plates of that batch, we do not have an explanation. According to Mr. Cotton, who advised us to use colloidal silver, on which grounds he had managed to make plates for interference color photography, we succeeded to get light sensitive layers of very small grains and of great consistency indicated by the measurements we carried out in the case of silver chloride, bromide and iodide. ==== Preparation of the plates ==== To a tepid solution (filtered warm) of 2.5 g special gelatin in 50 ml distilled water, 3 ml of a 10% colloidal silver solution are added. The resulting liquid of brown color, is poured on glass plates according to the methods used for collodion. The plates, arranged horizontally until gellation, are subsequently dried protected from dust. These operations are carried out under normal light, thus allowing for the production of a stock to be used occasionally as needed. The transformation of the colloidal silver into halide salts is carried out under subdued light, such as that of a candle or some reduced gaslight. The plate is introduced into a bath for which - after numberless trials - we established the following compositions (note: the quantities given do not correspond with the completed reaction but proofed to work most conveniently for our experiments): {| class="wikitable" border="1" cellpadding="5" |+ '''Chloride plates''' |- | align="left" | sodium chloride | align="right" | 2g |- | align="left" | copper sulfate | align="right" | 2g |- | align="left" | water | align="right" | 1000g |} <br> {| class="wikitable" border="1" cellpadding="5" |+ '''Bromide plates''' |- | align="left" | potassium bromide | align="right" | 2g |- | align="left" | copper sulfate | align="right" | 2g |- | align="left" | water | align="right" | 1000g |} <br> {| class="wikitable" border="1" cellpadding="5" |+ '''Iodide plates''' |- | align="left" | potassium iodide | align="right" | 2g |- | align="left" | copper sulfate | align="right" | 2g |- | align="left" | water | align="right" | 1000g |} "Bromination" is taking place equally well by using a diluted solution of cupric bromide; cupric chloride however, produced an opaque layer as well as did chlorine water (?) or iodine solution. During the preparation of the iodine (? rather cupric iodide I suppose - MM) bath, a precipitation of cupric iodide is forming which can be eliminated by filtering. As soon as the reaction stops - that is to say, when the yellowish color has vanished - one has to wash the plate, turned transparent meanwhile, exhaustively. At this stage the plates are very little sensitive. A means to this nuisance is to insert them into a second bath of 50g water to which 2g of a silver nitrate solution (0.5g AgNO₃ per 100g water) were added during 1 minute. They are washed with distilled water and dried in darkness. The developer has the following composition: {| class="wikitable" |- | |} The plates are fixed in sodium thiosulfate. ==== Conclusions ==== Due to the preliminary results, this study represents only some sort of beginning. Nonetheless, we are thinking the constants (?) introduced by Hurter and Driffield into photographic practice, can be applied to the fine grain plates we prepared. We will continue our work, systematically studying the use of chemical sensitizers and try to realize a perfectly orthochromatic "interference" plate. We meanwhile like to point out that the silver bromide plates prepared by flowing, are easily sensitized orthochromatically and allow for spectral recordings of the same brightness as Lippmann plates. The same is also valid for chloride. However, the sensitizers ("orthochromatisants") successfully applied to chloride and bromide, did not show any effect on iodide. Concluding this work, it is an pleasant duty to express my appreciation to professor Cotton (directeur du Laboratoire des Recherches physiques à la Sorbonne), for his support and interest. I equally thank my teacher, Mr. de Watteville, who introduced me into the delicate technique of interference photography... etc. =Making your own plates= by Jeff Blythe Diffusion method - estimated cost by Jean (no login) As promise, I post my estimated costs table for a batch of 20 holoplates made with the Jeff Blyth's diffusion method. Silane, LiBr, Pinacyanol come from Sigma-Aldrich All prices are in Euro (1 Euro ~ 0,97 USD) {| border="1" |- !Chemical !Price/Quantity !Diluted quantity !Quant/20 plates !Price/20 plates |- !AgNO3 (6%) |align="right"|18,11/10 g |align="right"|166 ml |align="right"|60 |align="right"|6,55 |- !LiBr (3%) |align="right"|11,2/100 g |align="right"|3300 ml |align="right"|300(*) |align="right"|1,02 |- !Pinacyanol (0,1%) |align="right"|16,81/250 mg |align="right"|250 ml |align="right"|7,5 |align="right"|0,5 |- !Ascobic Acid (1%) |align="right"|2,11/30 g |align="right"|3000 ml |align="right"|300(*) |align="right"|0,21 |- !Gelatin (15%) |align="right"|9/1000 g |align="right"|6666 ml |align="right"|100 |align="right"|0,14 |- !Chrome Alum (2%) |align="right"|3/100 g |align="right"|5000 ml |align="right"|300(*) |align="right"|0,18 |- !Silane (1%) |align="right"|31,16/100 ml |align="right"|10000 ml |align="right"|100 |align="right"|0,31 |- !Glass (4x5) |align="right"|12,5/20 |align="right"| - |align="right"|20 |align="right"|12,50 |} Total for 20 plates - - - 21,41 or 1,07/plate (*) I assume I change for each batch : - LiBr + Dye bath - Chrome Alum hardener - Ascorbic Acid sensitizer But please pay attention of this following note from Jeff about the LiBr bath : "please note that I myself reuse the dye/LiBr baths several times. A little bit of precipitate in the bottom of container (it is only AgBr) can be left there and the liquid poured off or the solution just filtered. So you can make many plates if you want to for the initial expence. The quantity of subbed plates you could make is enough for an industrial production run!" I don't calculate price for water, acetone and methanol because those products are cheap. First batch can seems expensive because you need to purchase relatively big quantity in regard of the used quantity and you need to some laboratory material. Hope this can give you the curiosity to test this easy method. Jean PS : my 2nd batch has failed because I don't care to dry plates enough after Chrome Alum bath! Results was presence of chrome salt who fog the plates. I'll try hardening gelatin with a bath of 1% formalin in DI water. =SM-6= *Sodium Hydroxide 12.0g *Methyl Phenidone 6.0g *Ascorbic Acid 18g *Sodium Phosphate (dibasic) 28.4g *Water to 1L =Stop Bath= *Acetic Acid 20g *Water to 1L =Safe Ferric Brilland Bleach= (rehalogenating Bleach designed by brilland) *Ferric III Sulfate 30g *Citric acid 30g *Potassium Bromide 30g *Deionized water to 1000 cc. You can use it and store it for a very long time at room temperature. It gives very low noise results. =AAC= *Ascorbic Acid 18g *Sodium Carbonate to give a pH of 10.5 *Distilled Water 1L =AGFA 80= *Metol 2.5g *Soduim Sulfite (anhydrous) 100g *Hydroquinone 10g *Potassium Carbonate 60g *Potassium Bromide 4g *Distilled Water 1L =GP-8= *Metylphenidone .2g *Hydroquinone 5g *Sodium sulfite (anhydrous) 100g *Potassium hydroxide 10.6g *Ammonium thiocyanate 24g *Distilled water 1L Mix 60 ml of developer with 400ml of distilled water. Develop for 6 minutes at 20C. =GP-2= *Metylphenidone .2g *Hydroquinone 5g *Sodium sulfite (anhydrous) 100g *Potassium hydroxide 5g *Ammonium thiocyanate 12g *Distilled water 1L Mix 15ml of developer with 400ml distilled water. Develop for 12 minutes at 20C without agitation. Develop with plate facing up and DO NOT agitate (you don't want to move the disolved silver away from the plate). =CPA1= *Metylphenidone .02g *Hydroquinone .65g *Sodium sulfite (anhydrous) 13g *Potassium hydroxide 1.4g *Ammonium thiocyanate 3.1g *Distilled water 1L Develop for 2 minutes at 22C. 3 seconds of initial agitation. =N6= *Metol .5g *Sodium Sulfite (anhydrous) 100g *Hydroquinone 45g *Sodium carbonate 30g *Potassium thiocyanate 5g *Potassium bromide 10g *Distilled water 1L Mix 1 part developer to 8 parts distilled water. =F1= *Amidol 4g *Sodium sulfite (anhydrous) 30g *Silver nitrate 3g *Potassium bromide 2g *Sodium thiosulfate 45g *Distilled water 1L Develop for 8 minutes. Fix for 2 to 3 minutes. =F2= *Metol 10g *Sodium sulfite (anhydrous) 100g *Silver nitrate 2g *Potassium bromide 2g *Sodium thiosulfate 30g *Distilled water 1L Develop for 30 minutes. No fix is required. =MM-Collo 1= From Martin: The best formula I ever made for a colloidal developer was: *Metol.............................2g *Ascorbic acid.....................7g *Methylphenidone.................0,5g *Potassium bromide.................3g *Potassium carbonate..............20g *Ammonium thiocyanate..............2g *Distilled water...................1L Dilute 1 : 50 or up to 1:100 (with distilled water) On PFG-03M it yielded extremely fine grains, resulting in a yellow emulsion (compared with the orange/red layer produced upon GP development). Development is quite slow, requiring > 30 min @ 20°C. =VR-P developer= *Sodium Sulphite anhydrous 194 g *Hydroquinon 25 g *Potassium Hydroxide 22 g *Methylphenydone 1.5 g *Potassium Bromide 20 g *Potassium Metaborate 140 g *1,2,3-Benzotriazole 0.1 g *Distilled water to 1 L Working solution: 1 part of VR-P Developer + 6 parts distilled water =Phillips' Ferric Nitrate Bleach= *150 g Ferric Nitrate *33 g Potassium Bromide *20 g Glycerol *300 mg Phenosafranine *500 ml Isopropyl *500 ml Distilled Water =Phillips' PBQ-1 Bleach= *2 g PBQ *30 g Potassium Bromide *1.5 g Boric Acid *1L Distilled Water =Phillips' Ferric EDTA= *30 g Ferric Sulfate *30 g Di-sodium EDTA *30 g Potassium Bromide *10ml Sulfuric Acid *1L Distilled water =D-14H= From Hans: I got this formula from http://silvergrain.com/labs/Print_Developer_Recommendation?title=Print_Developer_Recommendation It does not to be mixed in a A and B solution and I have found that it works just as good as the Ultimate safe holographic developer. I made on adjustment to the original formula in that I left the KBr out because I don't think that there should be KBr in a holographic developer. Development time is about 1.5 minutes. *Dimezone S 0.2g *ascorbic acid 6.0g *sodium sulfite, anhydrous 12.0g *sodium carbonate, monohydrate 30.0g *triethanolamine, 99% 5.0ml *salicylic acid 0.5g *water to make 1.0 liter target pH 10.4 ± 0.2 =Ascorbate Developer= But I contend that the best way of dealing with ascorbate developer stock and it is a way we have been successfully using for some years in our labs is to "A and B" it. For A we have a 500ml bottle with: *20g ascorbic acid *3g Metol (4-methylaminophenol sulfate) *and top it up with 500ml deionized water for B we have a 500 ml bottle of *50g sodium carbonate anhydrous *15g sodium hydroxide top up with 500 ml deionized water. (This one should be labeled "very caustic") Just use equal volumes of A and B from then on. Now there are 3 bonus points for using Metol instead of phenidone. 1) is that phenidone is quite a strong silver halide solvent and tests have proved that metol gives brighter holograms. 2)The second point is that metol has a hardening action on gelatin and its effect on speeding up the development time over what you would have with just alkaline ascorbate means that even notoriously soft emulsions juch as PFG-03 can be in and out of the developer bath into a stop bath (~5% acetic acid ) in around 20 seconds, before the gelatin is seriously attacked. Assuming of course your exposure level was good enough. 3) Metol is a weaker reducing agent or developer than alkaline ascorbic acid. When Metol gets oxidized it goes really dark brown so this is a useful indicator to tell you when your bath is exhausted because it wont go severely dark until most of the ascorbate has been oxidized. A mild yellowing like weak tea is quite OK . Dont forget to use the floating dish method of 2 closely fitting plastic dishes with the upper dish keeping most of the air out as it floats and acting as convenient agitator as well. Acid ascorbate in the stock soln A will not seriously oxidize for a year. (Slight yellowing is perfectly OK . ) jeff =Metol-Ascorbate developer courtesy of Laser Reflections= The formula is as follows: Metol-Acorbate Developer (Part A + Part B) Part A: *Metol 10g *Ascorbic Acid 80g *Water to 1000ml Part B: *Sodium Carbonate Anhydrous 120g *Sodium Hydroxide 14g *Potassium Bromide 4g *Water to 1000ml Use it in combination with a Fe-EDTA bleach - a safe, stable bleach which has a long shelf life. Fe-EDTA Bleach *EDTA (2Na) 30g *Fe(III) Sulfate 30g *Potassium Bromide 30g *Sodium Hydrogen Sulfate Crystals 30g *Water to 1000ml =Sergey Vorobyov's developer - OD-1= New postby Gall » Mon Nov 08, 2010 12:05 pm Some time ago Mr. Vorobyov invented a developer for silver-halide holograms that does not contain any rhodanides. It is ideal for both beginning and advanced holography. The original Russian article is here: http://www.holography.ru/tech8rus.htm Original formula: *Metol = 2 g *Sodium Sulphite (anhydrous) = 25 g *Hydroquinone = 5 g *Borax B[sub]4[/sub]H[sub]4[/sub]Na[sub]2[/sub]O[sub]7[/sub] = 2 g *Sodium Thiosulfate (photographic fixer) = 6 g *Water = 1000 ml Here sodium thiosulfate replaces rhodanide. It dissolves AgBr so that the process is the physical one and not the chemical one. Simplified formula - made from Kodak D-76, ideal for beginners (image is slightly worse but still works): *Take Metol and Hydroquinone mix from two ready-made 0.5l D-76 packages (2x[1 g + 2.5 g]). *Take Sodium Sulphite and Borax mix from one package (1x[50 g + 1 g]). *Add 6 g (one teaspoon) neutral fixer (Sodium Thiosulfate). This will result in following: *Metol = 2 g *Sodium Sulphite (anhydrous) = 50 g *Hydroquinone = 5 g *Borax B[sub]4[/sub]H[sub]4[/sub]Na[sub]2[/sub]O[sub]7[/sub] = 1 g *Sodium Thiosulfate (photographic fixer) = 6 g *Water = 1000 ml Dissolve Metol and Hydroquinone first in some warm (40-45 centigrades) water, then add everything else, add water to 1000 ml and filter the solution. The resultiong solution should be mixed with water 1:4 before use. Develop around 10 minutes at 18 centigrades. =Zip1= For transmission Holograms. I have been using my own developer for the last three years which is extremely active requiring much shorter exposure times than others (JD-2, JD-4, Pyro, etc). Used it for reflection and transmission on Slavich (especially VPR-M) and Agfa films and plates (8E75/56). Sometimes EDTA and sometimes Dichromates bleaches: Zip1: *Metol 1gr, *Hydroquinone 1gr, *Phenidone 0.5gr, *Sodium Sulphite 30gr, *Ascorbic Acid 10gr, *Potassium Hydroxide 30gr, *water to make 1 litre Dave I've used it for reflections in place of the pyro developer and with the dichromate bleach. It also over comes the hassle of accidently getting stained fingers with the pyro developer if you forget to put the rubber gloves on. The main benefit I've found is that the image brightness is on a par with the other developers with the bonus of shorter exposures. The mix of the Metol, Hydroquinone and Phenidone with the Potassium Hydroxide is quite an active combo. I'm not really surprised and certainly these chemicals are cheaper than pyro and catechol. 6f2b3851790671815c8defecc14be1f1f8b2a856 0 179 1604 206 2013-05-06T18:42:41Z Admin 0 /* Paulos Test */ wikitext text/x-wiki The Blyth Colour Tuning method originated from an observation Jeff posted to the forum and its testing was taken up by a number of people. The results were very promising. The original thread is here: [http://www.holographyforum.org/phpBB2/viewtopic.php?f=2&t=5224 Blyth Colour Tuning Thread] ==Preperation== Stock Solution: *15g Citric Acid *100ml Water Dilute as needed. Soak the hologram to be swelled for 30 minutes. Then dry. Amazingly squeegee technique is not very important here! ==Paulos Test== I cut a 15 x 20 cm film hologram in 4 pieces and applied Jeff's Citric Acid solution method. The result: # (upper left): untreated (514 nm) # (upper right) 11.75 % Citric Acid (=15% x 0.75) # (down left) 7.5 % Citric Acid (=15% x 0.5) # (down right) 15 % Citric Acid {{note | Based on the progression of color shifts, #2 and #3 may have been reversed with respect to acid concentration in the original article. | gotcha}} [[Image:citric.jpg]] The photo is not the best one (the hologram is free of any noise), but the effect of the various concentrations is obvious. In comparison to sorbitol-treated holograms, the overall quality is better. * Exposure at 514 nm * Holographic film: Finegrained HF-53 from ORWO * This emulsion is much harder than Slavich material. ==Theory== From Jeff Blyth I have been doing a bit more on this since I have receiving an appreciative email from Rob Taylor (Forth Dimension Holographics) about the newly found virtues of the citric acid post swell system.. In it he mentions how forgiving it is to the squeegeeing. technique. I have noticed this too and have just been wiping off the excess citric acid solution casually with tissues and have not seen smeary streaks of darker red which would have occurred with sorbitol solution. Now this convenient fact indicates something about what is happening down at the molecular level. Also I just might possibly have discovered something of interest for DCGers to investigate as a means of changing those finished too-blue colored hologram into red ones –a trick which I think John Pecora has discussed more than once on this Forum over recent years. However with only 2 days of observation I am being rather optimistic to think I have a long term answer to that old perennial DCG problem but I hope that DCG’ers will now try some experiments with old “Bluies and Greenies” as John puts it before just recycling the glass! I will go into a bit of DCG detail at the end of this post. First though I need to hypothesize what is happening at the molecular level to try to understand the observation about squeegeeing technique being less critical with citric acid solution compared to sorbitol or glycerol solution. So as we all know, the building bricks of gelatin are amino acids. In neutral pH conditions these make themselves into internal acid–base structures with the negative – positive ions neutralising each other. The swelling in water is caused by both the positive and negative ions choosing to open themselves up to accommodating lots of water molecules which take on partial induced charges opposite to the ions they surround. So the amino positive ions get surrounded by a cloud of partially negatively charged water molecules and vice versa around the negatively charged acid groups . This allows the original electrostatic attraction between the oppositely charged components of the amino acid to slacken and the components to move apart by a factor of 2 or 3 times their unswollen distance. An accepted way of keeping gelatin based holograms swollen with water has been to try to replace a lot of the water with non- volatile very hydrophilic “polyalcohols” such as glycerol or sorbitol . These alcohols get involved in the cloud of water molecules surrounding the charged amino acid groups. The size of this cloud of water molecules around the oppositely charged amino acids is very imprecise , variable and dynamic, (this description will be important), it instantly can change with temperature and humidity changes so it is difficult to control color changes of gelatin based reflection holograms. (They act as superb humidity change sensors---a fact I am personally gaining from in the development of “Smart” holograms to test for water in aviation fuel.).. Just breathing on them can make a wavelength change of tens of nanometers as we all know. However in the case of a hologram treated with citric acid and then blow dried at room temperature we are left with a swollen gelatin which is different from the case of one swollen with water plus sorbitol or glycerol. In citric acid we have in effect the line of 3 carbons in glycerol now with their alcohol groups (-OH) replaced by carboxylic acid groups (-COOH) except for the central carbon which has the (-COOH) added in place of H leaving one alcohol OH still there (more on this later). These –COOH groups introduce a different effect to cause the swelling of the gelatin. This time the citric acid (-COOH) groups can partially displace the original internal (-COOH) groups from their attraction to the amino groups. These displaced (-COOH) groups are still firmly attached to the gelatin biopolymer of course and are not free to wander off in solution so the rest of the citric acid molecule is forced to be accommodated into the gelatin structure as most of the surrounding water is now evaporated off thus leaving the gelatin in a swollen state when it is left to equilibrate with ambient humidity.--- Fortunately it is a chemically weak arrangement easily completely reversed by plenty of fresh water so that it becomes energetically more favourable for all the ions involved to go back to surrounding themselves with water-molecule clouds again . The upshot of this is that if you are not satisfied with the color of your treated hologram you can go back to square one without any difficulty . I have not found the slightest trace of the effect of citric acid after rewashing in water. --An important feature for any precious holograms whose color you are trying to tweak. In the above model one can sense why the removal of excess surface liquid on a hologram treated with citric acid solution is more forgiving (in the final result) from an unequal treatment with a squeegee blade compared to the same situation with an excess of sorbitol solution. In the case of excess sorbitol that final sheath or cloud of water/sorbitol molecules which I described above as "very imprecise , variable and dynamic", as they surround the amino acid ions they can be far too sensitive to small variations in residual water causing corresponding local variations in reddening of the final replay color as the clouds expand or contract. Whereas in the case of the citric acid, the reddening is caused mainly by a specific alteration of the internal molecular structures of the amino acids and perhaps not much by a variable cloud around the ion.. Now experienced DCGers have long since found that you cannot change the color of a finished too-blue DCG by playing around with sorbitol treatment. Anything that attracts water is anathema to DCG holograms. So the question naturally arises can one somehow do it with this different citric acid mechanism? Well I took a blue green finished DCG , left it in 10% citric acid for 10 mins, (I cut the time down from my previous 30 min recommendation because I noticed the gelatin was starting to come off the glass after 5 mins) I then briefly wiped it with a tissue an plunged it into a stirred beaker of ~100% ipa at room temperature. ( I needed to avoid using ipa/water solution as it was likely to loose citric acid. The acid fortunately seemed to prefer to keep its weak attraction to the gelatin rather than dissolve in ipa. only). The good news is that the resulting hologram after a long cool blow was a deep red hologram instead of a blue green one. But the bad news is that that only 3 hours later it had vanished.. But ……don’t go away yet…………. I tried a variant. …… The problem was of course likely to be too much water attracted in still--the water cloud around ions was probably still there to some extent which caused the air- void fringe structure to be unstable and disappear. So could an improvement be got by using an alternative organic acid without a residual alcohol –OH group still present? So I tried succinic acid instead. This is a non- poisonous but quite strong organic acid (a “natural” product too) with the 2 alcohol groups in ethylene glycol replaced by –COOH groups. I found that it saturated at room temperature at around the 6% level but treating green silver halide holos with it did make useful color shifts to yellow (in the case of BB plates but not in the case of the harder Fuji film,) it was though much less effective at causing the amount of color shift you can get from the same concentration of citric acid. The question is then is this less hydrophilic acid able to keep a color shift in DCG? So far my test sample is still maintaining its green to orange shift after 36 hours but I would not put any money on its permanence. So I am hoping some DCGer will pick the idea up, get in a bit of succinic acid and play around with sealing it up etc. ---it could be an interesting alternative to recycling those “Bluies”. Jeff 1a03e062748aa46889f9d70563c5eacbb344a651 0 591 1850 1333 2013-05-06T22:12:19Z Admin 0 wikitext text/x-wiki Wave plates consist of some birefringent material (like quartz) and modify the [[Polarization]] of a laser beam. Lambda/4 wave plates (also called 1/4 waveplates) turn linearly polarized light into circular polarized light, and as such are not of great use to holographers. Lambda/2 wave plates (also called half-waveplates) rotate the [[Polarization]] of a laser beam by a fixed amount, depending on the orientation of the preferred axis. They thus need to be fixed in a rotation mount. A waveplate is usually only usable at a single frequency, in order to rotate the polarization of a multi-colored laser beam see [[Fresnel Rhomb]]. Lambda/2 wave plates are often used by holographers for the following reasons: *For rotating the polarization of a laser to avoid holograms with superimposed "wood grain" structure. This arises from interference between beams reflected from the front and back sides of a holographic plate. One technique to avoid this is to use [[Index Matching]], but a simpler method is to illuminate the plate by a reference beam at the [[Brewster's Angle]]. When properly polarized, there won't be any reflections and thus, no interference. When the reference beam is tilted horizontally (vertically), then one needs horizontal (vertical) linear polarization of the laser beam. Small lasers like tubular HeNe lasers can simply be rotated to achieve the correct polarization, but this won't work for larger lasers like [[Types_of_Lasers#Argon_Ion_Lasers|argon lasers]], which are usually vertically polarized. For these, a Lambda/2 (half-wave) waveplate can be used to rotate the polarization appropriately. *For rotating the polarization of the reference with respect the polarization of the object beam, to maximize image contrast or to achieve special effects. If you put a polarizer at the film plane aligned to the polarization of the unaltered object beam so you can see the reflections and place a 1/2 wave plate in the object beam you will see the relative brightness of the reflections dim as you rotate the polarization off axis. Rotate the 1/2 wave plate so the reflections and the diffuse light from the object have the "desired" brightness. Also, make sure that any bright spot is not exactly on the film plane when making an H2 or it will burn out. *In conjunction with a [[Holography_Technology#Cube_Beamsplitters|polarizing cube beam splitter]], a pair of Lambda/2 plates is the best method to split a laser beam into two beams with a variable beam ratio. Wave plates are usually quite wavelength dependent and will work well only very close to their design wavelength. Multi-order waveplate are more wavelength sensitive than zero-order wave plates. There exist however broad band wave plates as well. Usually wave plates are expensive and not too often available as surplus - if you see one, get it! For the hobbyist, there are also the following two options: *If she happens to have a few waveplates designed for other wavelengths than the desired one, try to mount them in tandem and play with their relative orientations: there is often a spot where a linear rotation can be achieved. Even using Lambda/4 wave plates can sometimes work in this way. Another reason to catch any conceivable wave plate on ebay! *LCD screens from old electronic pocket games (in particular Nintendo types from the early 80's) sometimes can be used as broad band Lambda/2 wave plates. This needs to be tried case-by-case. The relevant piece is the top glass plate that needs to be taken off. The disadvantage is often poor optical quality (can be remedied by a [[Holography_Technology#Spatial_Filters|spatial filter]]), and interferences from front and back sides that lead to an uneven illumination. Commercial wave plates are usually anti-reflection coated and so avoid this problem. *Stacks of Seran Wrap can also be stacked to the right thickness for a quick and dirty wave plate. *If you take a piece of mica and flake a few flakes off one may be the right thickness to be a multiorder wave plate. This is another quick and dirty method. [[Category:Optics]] fda81821bf8d676901f0d43e9b1fe4b9491091b6 0 588 1848 1327 2013-05-06T22:13:17Z Admin 0 wikitext text/x-wiki Veil Coating ==Veil Coating - Part I== The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70F.) Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45 degree angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. ===Post Spinning - Part IIa=== Take the plate and immediately place it on a turn table and spin it as 78 RPM’s. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. ===Post Leaning/Lying - Part IIb=== If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. ===Re-Using Emulsion - Part III=== If you run out of emulsion in the pouring container while coating, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. Allow the emulsion to come back up to coating temperature of 110 to 120F. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. Although refilter does not have to be done during one session if things are kept clean, I suggest refiltering after refrigerating and re-cooking. ==Dave Battin's Article on Veil Coating== Having tried all the methods available to most hobby holographers, I've found the best method for me is the veil coat method. I have attached a still shot to give you a preview to this method, and I plan on showing a step by step instructions so all should be able to coat easily. please see the video clip at the bottom of this page to see this method in action, sorry for the weird color ,as im actually making DCG film under a yellow/red safelite [[Image:VeilFig1.jpg]] The size of the glass is 4"x16" if i trim off one inch the top it will yield me Three nice 4x5s. When acquiring glass I have found a great source is at your local art store, the type that has a special every week, (here its called Michael's), Its the replacement glass sold for picture frames, located in or near the framing department. It comes cleaned sealed and slightly lighter/weight than the regular 1/8" glass found at the local hardware store. The largest I can get is 16"x20" for @ $5 each, not bad for coming cleaned and ready to cut .................. subbing will be next [[Image:VeilFig2.jpg]] I have found it much easier to cut the glass into 4”x16” pieces before subbing. [[Image:VeilFig3.jpg]] A simple jig to cut your glass will give you nice consistent cuts every time. By banking your glass to the stop and placing the proper width spacer on top, simply bank your glass cutter against the spacer and slice. It’s best to provide a little lubricant to help the cut a little (I lick the cutter first). Now that my glass is cut, I'll prep the surface for coating. This glass is pretty clean already. If you’re unsure, I would soak it in a 20% Clorox Solution (soak over night), and after a quick water wash, soak in the Cascade (dishwasher soap) and water mix (I use a small handful for 2 gallons of water or so) again soak overnight after a slight scrubbing action using a plastic scrubby pad. [[Image:VeilFig4.jpg]] After removal of the glass from the Cascade, I give it a quick dip into clean water and then a final plunge into what they refer to as (Trisodium Phosphate) substitute. Where I live, they won’t allow the use of the real TSP, as it’s bad for the ground water. Allow to dry by leaning on wall, sitting on a paper towel. [[Image:VeilFig5.jpg]] The glass is now ready to be coated, but we must add a few extra items to make things easier later on ………………………… [[Image:VeilFig6.jpg]] Well, the glass is almost ready to coat. We will have to attach a few pieces of tape and paper to make this work correctly. [[Image:VeilFig7.jpg]] I do all the work under my laminar flow booth. It helps to place your plate (the glass will now be referred to as plate) on some type of pedestal (as shown) or block of wood. (photo A) Start by placing the plate face down on the pedestal and applying plain old ordinary scotch tape to both long sides of plate, adhere tape directly to the back of the plate, allowing only half of the tape to hang off the sides the entire length of the plate (photo B). I call these gutters. These will allow you to coat your plate up to the very edge without any waste. Once the gutters are in place, turn your plate face up, and again place on the pedestal. Now using a short piece of tape slightly longer than the width of your plate, attach it to the top, adhering directly onto the face of the plate, again leaving half the tape to hang off the top (photo C). Now that the top tape is adhered, we will now apply the “Tab”, a small 1x5 inch piece of paper applied from the back of the plate stuck to the tape along the top. This tab will be used numerous times throughout the operation so be sure its adhered well (photo D). Your plate should now look like this: [[Image:VeilFig8.jpg]] The paper tab I attached to the top of the plate, will now act as a handle and I can hold it while doing a final cleaning, I lay the glass across my leg and wipe it clean (front only)using a folded paper towel and simple Windex glass cleaner ,always spray on the towel and not the glass! With my method of coating I felt to lean is to be constant! The angle of incline is not so important, but its to always repeat the same angle, I achieve this by placing the plate in a holding jig, see the video to help explain, the film is now ready for coating . A few minuets after coating , the paper tab will now allow you to attach a large paper clip, and hang your film to dry. By using a lab base and thin rod clamped horizontally, its easy to hang 12 4x5s to dry! The blow dryer I use is old and weak! But it has two settings hi/low heat, at low it is very weak (blowing), and you will see me blowing close to the wet emulsion. Most new blow dryers will be way to powerful for this. To apply the emulsion I use a simple squirt bottle, very easy to regulate flow, with the current bottle, I can coat three 4x16 plate before I have to recharge the bottle. [http://www.holowiki.com/HoloWiki/images/coatmeth.wmv Dave Battin's Coating Video] (dead link) [http://www.youtube.com/watch?v=b0Toqidt0eo Dave Battin's Coating Video on YouTube] [[Category:Techniques]] 58a11b0aecc033da9d50e4427644900e63859979 0 576 1842 1303 2013-05-06T22:21:40Z Admin 0 wikitext text/x-wiki '''Correcting Milky Holograms''' Milkiness is caused by the film being too soft. There are many ways of fixing this problem (making the emulsion harder) but increasing exposure is not the best way. It sounds as if the gelatin you are using is naturally soft. So let's look at some other ways to use your gelatin and get it harder. You could try any of these or combination of these with a shorter exposure time. #First, shorten your exposure let's say by half (10min). Then after the exposure hold the hologram in your hand by the edges and with the laser shutter open, hold the hologram in the laser light and keep moving it side to side. The idea is to get additional crosslinking and thus hardening without actually creating any more fringes. Do this for the remainder of time of your original exposure so do this for the 10 minutes you took off the original time. If you cut your exposure to 5 minutes then do this for 15 minutes. After some testing you may be able to cut this additional lighting time down. #After a shorter exposure, 5 or 10 minutes, and before processing put the hologram in a lab oven (do not contaminate your cooking oven) and bake it at about 120F (49C) for 3 to 5 minutes. It's best to have a piece of flat steel in the oven to lay the hologram on, so when you put the hologram in the oven, it heats up all at once. Then when you take the hologram out of the oven, place it on anther piece of flat steel to cool it evenly. #Prior to exposure do the above baking technique. Then let the hologram cool and stablize to ambient room temperature and humidy before shooting. #Decrease the amount of water in your homemade "Fixer" (pyrosulphate/alum/water 20g/4g/400ml) and increase your fixing time. You'll have to test the increased fixing time as you never stated how long you fix. With higher concentrated formula, you may not have to increase fixing time at all but a little testing will tell. If you get too long, greater then 2-3 minutes, then decrease water. It's best to keep fixing to about 1 - 2 minutes. Try 20g/4g/300ml. #Put a couple of drops of Glycerol (glycerine) in your original emulsion formula. This will help speed up dark reaction in those 24 hours which will essentially cause the film to be a little harder. #Age your plate in a very dry area for 2 maybe 3 days instead of 1 day. You could make a few plates and shorter expose a plate each day and see what happens as the plate ages. [[Category:DCG]] 34cecd5383d4192002f1b29daa48494c6d0a8c98 0 573 1840 1297 2013-05-06T22:22:53Z Admin 0 wikitext text/x-wiki === Pinhole Calculation === As per Newport. D = Fw/a , where D = Pinhole Diameter F = Objective lens focal length w = Wavelength of laser (sorry no greek letter on my keyboard) a = Beam radius at input to lens More.... [http://www.newport.com/store/product.aspx?id=3873&Section=detail&lang=1# "Newport Pinhole"] === Calculating Laser Power vs Film Requirement vs Exposure Time w/Sample === Joules = Watts x seconds thus 1 mW = 1 mJ/second 1 inch = 2.54 cm per square inch = 6.45 cm² For a film requiring '''100 mJ/cm'''^'''2''' Plate length (2.54 cm) x width (2.54 cm) = '''6.45 cm'''^'''2''' Laser putting out 10mw = '''10 mJ/second''' <br> '''10 mJ/second''' /&nbsp;'''6.45cm'''^'''2''' = 1.55 mJ/cm²/second '''100 mJ/cm²&nbsp;'''/ 1.55 mJ/cm²&nbsp;/ second = 64.5 seconds This is just a basic starting point based on the film energy requirement. Adjustments need to be made for laser light losses, processing etc.... === Detecting the Emulsion Side of the Plate === Most of these can be tried with a used piece of film plate with the lights on for practice. Note: These tricks rely on the fact that only one side is gelatin; with the Fuji film both sides are gelatin. If you breathe on the plate, the side that does not fog will be the emulsion side (no condensation occurs on the emulsion side because the gelatin absorbs the moisture). (This does not work for the Fuji film as it has gelatin on both sides.) Look at the edge of the glass with a safelight - the cleanest (non-ragged) edge is the emulsion side. With a bit of practice you can detect the difference in the dark by rubbing your thumbnail along the edge. If all the plates are oriented the same way, you can label the box ''emulsion this side -&gt;'' The two finger method: moisten your thumb and index finger and pinch them together a few times. Now do the same motion with the plate between them, and it should be easy to feel which side is the sticky emulsion side. === Got old plates? === I have stacks of failed plates. Do yourself a favor now that you have some scrap plates: Spray paint one of the ruined jobbies white and use that as a dummy plate when setting up. Both sides and the edges. You will find this very useful when it comes to carding off light that would otherwise enter the edges of the glass as well as for checking the quality of your reference beam. A clean white surface is also nice for making sure that you have no specular reflections from shiny places on your object(s)... [[Category:Techniques]] de67b6f5f9d16b94e8d9d52481200130874f9b93 0 570 1834 1291 2013-05-06T22:48:24Z Admin 0 wikitext text/x-wiki ===Dust Hoods=== Keeping your work area dust free is a prime consideration when making your own emulsions. HEPA work stations are commercially available but are expensive. A home made work station can be easily made. [[Image:LaminarDetail.jpg]] John Pecora built this nice bench top Dust hood for DCG plate coating. On the left is the front view and on the right is a side cross section. For the back wall he used a plastic material that looks like square tubes with a screen covering. [[Image:CommercialLaminar.jpg]] This is a Commercial HEPA work station made by [http://www.nuaire.com/ NuAire]. It has pre-filters on the bottom with a squirel cage blower and the entire back of the work area is one large HEPA filter (4' x 3'). There are four 4' flourescent bulbs in the top. In order to make sure there are no air vortexes that can trap dust it is important to have the air flow over the entire bench in a laminar fasion. In order to insure a laminar flow the air needs to be directed through a parallel series of tubes. A bunch of straws work perfectly. In order to test the flow one can take a candle and put the flame in different places in the work area. Places where the flame flickers have turbulence and are unacceptable. ===Fume Extraction=== Processing with formaldehyde and alcohols are common in processing holograms. The fumes are dangerous and provisions should be made for venting them saftly outside. A simple bathroom fan is insufficient. Commercial suppliers like [http://www.mcmaster.com McMaster Carr] and [http://www.mscindustrial.com MSC Industrial] have explosion proof fan assemblies in the $500 range. A good rule of thumb is to have enough venting to exchange the complete air in your room 30 times per hour. Check your local regulations for more requirements. ===Processing Areas=== The processing are needs to be designed with a few considerations: *Light tight *Washable surfaces *Dust free *Running water *Lockable chemical storage *Counter space for processing trays ===Safe lights=== In order to see while you are working it is important to have some light. Fortunately if you are using film that is only sensitive to red you can make a green safelight. You should test your safelight before you use it. If you are using long settle times it is wise to make sure no safelight hits the bench during the settle period. ====Testing Safe Lights==== Do a preliminary test of reflecting the light off of a diffraction grating, CD or DVD. Shine the safe light at the grating and bounce the reflection back to your eyes. If it looks the same then you are looking at the zero order reflection, rotate the grating or CD until you see a reflection that looks like a rainbow. This is a higher order reflection. If you can see red in this reflection then your light is not safe. ====Exposure Test==== The next test is to get out a piece of your film. Find the uncoated side. Place a piece of electrical tape down one side to make a test patch that has not been exposed. Put the film about a foot from your safelight with the tape facing the light. Add one piece of tape at 15 seconds, 30 seconds, 60 seconds, 10 minutes, 30 minutes. At 60 minutes put the plate in developer. If your plate turns completely black then your safelight is not usable. If only the 60 minute or 30 minute lines develop you are probably OK. ====Safe Light Types==== '''For Red Sensitive Film''' *Lime Light: The easiest light to use is a "Limelight" night light. It is very low power and mostly green. If you add a Rosco Gel #90 available from a theatrical supply shop it will be very good but very low power. Attach the gel with electrical tape. John Klayer uses a row of gelled Limelights above his bench. *Kodak Safe Lights: Kodak makes a #7B and #3 green saflelight filters (#3 is recommended by Shoebox Holography) suitable for red sensitive holographic films. *Home Made Lights: Just using a piece of Rosco #90 (Theater Gel) over a conventional bulb is not enough. Use two layers of #90 or better to have one layer of #90 and one layer of #95. #95 lets in too much deep red to use alone and #90 lets in too much yellow that the Slavich materials are sensitive to. *MiniMag Flash Light: Use Two layers of Rosco #90 or better yet one layer of #90 and one of #95 for red sensitive film. *T40 EncapSulite fluorescent bulb covers can be used for holographic safelights. [http://www.flexopress.com/production/encapsulitelightsleeves.html EncapSulite] For general information about Safelights see: [http://www.kodak.com/global/en/consumer/products/techInfo/k4/k4Facts.shtml Kodak Safe Lights] [[Category:Equipment]] 97101ccb50e3a94e4c5c5e5c494b3859ff8f148c 0 522 1832 1195 2013-05-06T22:49:06Z Admin 0 wikitext text/x-wiki ==Setting up a table saw== *Set the blade to full depth. *Measure the blade to table angle with a square. *Adjust the blade angle to square. *Set the blade depth. If making a through cut you want the blade to not be higher than 1 tooth above the work. *Adjust the fence to position. Very carefully measure from the edge of a front tooth to the fence and then measure the tooth on the back edge the blade the fence. Adjust the fence until they are equal and the fence is square. *Setup the miter carage ==Choosing the proper blade== ==Cutting Aluminum== ==Cross cutting== ===Cross Cutting with a Fence=== ==Safety== [[Category:Uncategorized]] bcf1c6b6b19ea0edde170a7aab45d7158fade44d 0 517 1826 1185 2013-05-06T22:49:53Z Admin 0 wikitext text/x-wiki Staight edges, as pointed out, are to lay out straight lines and to check if things are straight and flat. Wooden materials are bad to use as staight edges as they usually have bows in them. Squares and metal rulers are good straight edges. Plastic rules are also good straight edges. A drywall square has a 4 foot straight edge with measured increments. For very long straight lines, a chalked string line (called a snap line) can be used. In expensive large straight edges can be purchased as "flat ground steel" from industrial suppliers like MSC Industrial or McMaster-Carr. Be very careful with your straight edges as they can get easily get nicks that will effect their ability to measure flatness. ==Testing a Straight Edge== If you compare any three straight edges thay can only be straight if they all match. Any two straight edges can match if they have the same curve. But, for three to match they must all be straight. [[Category:Uncategorized]] 470323bc47e7b8d7dfe65b4836ae1c15b37dba1b 0 514 1820 1179 2013-05-06T22:50:37Z Admin 0 wikitext text/x-wiki Some emulsions are harder than others. Harder emulsions can take squeegeeing better than softer ones. BB-640 and PFG-01 are pretty hard and sqeegees well; Ultimate and PFG-03 are pretty soft and easily scratched. *Squeegeeing works better when a wetting agent is used. Photoflo works well, but some think it may contribute to printout. Others use the Ilford product, or just a drop of liquid soap in the final rinse. *You didn't say if you were using plates or film. For film, use a piece of clean glass to support it. Stick the film to the glass emulsion side down a la index matching and squeegee the back. The remove the film, squeegee the glass dry, and stick the film back onto the glass emulsion side up and squeegee that side last. *For glass plates, the sharp edge of the glass will make cuts in the rubber blade, which will leave streaks next time. To minimize this problem, make a jig that keeps the wiper blade in the same position relative to the plate every time. This way the cuts will always be close to the edge of the glass. [[Category:Techniques]] 25b005d8c6173960ac4e06706bad0008a89a3f49 0 511 1816 1173 2013-05-07T01:39:44Z Admin 0 wikitext text/x-wiki = Lippmann’s photography on dichromated gelatin plate = Sogonkon' A. B. {{Note | This article was transcribed from the text in the [[Media : Sogokon Lipp phot on DCG.pdf | file available here]].}} The research of properties of Lippmann’s images obtained on dichromated gelatin plate shows that image color depends on wavelength of radiation as well as on its intensity. It relates to heterogeneous swelling of gelatin and structural changes of its unirradiated parts at fast dehydration. Unusual behaviour of Lippmann’s images on dichromated gelatin plate may be used for producing selective mirrors for reflecting graphic information and date registration and image processing. == Introduction == There is [1] a method of obtaining color image based on registration of standing waves in the volume of thick transparent photographic emulsion. Period of registered interference structure is unambiguously related to the length of the wave of radiation influencing the plate. This assures right color rendering of photographed image if disposed to white radiation. This method wasn't widely adopted because of big technical problems. Development of holography leads to creation of a totally new technique of experiment and new registering mediums. There appeared some announcements that Lippmann’s images have been tried on modern emulsions like ЛОИ-2 [2,3] and on dichromated gelatin [4,5]. The aim of this work is to investigate the behaviour of Lippmann’s images made on dichromated gelatin as well as mechanism of image formation and possibilities of its application on practice. == Method and results of experiment == Lippmann’s method is basic for making dichromated gelatin plates [6]. Holographic plates ПЭ-2 and ЛОИ-2 were placed into acid fixing solution then washed in running water and dried at room temperature. The plates were sensitized right before exposure. For this the plate was placed for 5-15 minutes into 1-5% solution of dichromated ammonium and after its runoff dried by hot air current at temperature 100-150°C. The duration of drying is 3-5 minutes. [[Image:LippmannFig1.jpg|center|Image 1. Scheme of device for contact printing of Lippmann’s images. 1 – light source (laser or mercury lamp), 2 – lens, 3 – negative, 4 - dichromated gelatin plate.]] Scheme of device for contact printing of Lippmann’s images is displayed on image 1. Widened laser beam is directed onto registering medium. The radiation passed through reflected from plate glass spreads in reverse and forms a standing wave in the volume of registering medium the amplitude of which depends of negative passing. As the source of radiation lasers ЛПМ-11(442nm) and ЛГИ-21 (337nm) and mercury lamp ДРШ-250 were used. Besides direct projecting printing of enlarged images was realized with help of a usual photographic enlarger. Processing mode of exposured plates hardly differed from that of dichromated gelatin for obtaining hologram [7]. Images obtained using the foregoing method have a number of interesting qualities. If watching at an image in reflected light (almost natural light rays falling) different parts of the image get different colors according to density of initial negative. The image gets blue color under transparent parts and red color under opaque ones. Half-tints of negative are reproduced by hues from orange to green. From this follows that interference structure period depends on length of radiation wave as well as on its intensity. A Lippmann’s image if placed on a black sheet of paper and watched at broad angle will be black-and-white. Gelatin remains transparent under transparent parts of the image and gets milkwhite under opaque parts. In this case the image is not reproduced by light absorption but its dispersion that resembles the properties of display on vesicular materials [8]. To investigate the dependence of image color on the exposure within one plate a number of exposures was done by collimated laser beam. There were made also photos of sensitometric wedge image and then spectrums of transmission of the received images measured. On image 2 there are spectral characteristics of images obtained on ПЭ-2 plates sensitized by 1% ammonium solution at exposure by laser ЛПМ-11 (image 2,a) and ЛГИ-21 (image 2, г). It follows from the analysis of spectrums that spectrum reflection width (image 2, e), length of wave maximum reflection (image 2, в) and density of image (image 2, б, д), change according to exposure amount. It is significant that length of wave maximum reflection at considerable exposure does not correspond to the length of radiation wave of the record. It’s due to increasing period of interference structure at layer processing. [[Image:LippmannFig2.jpg|center|Image 2. Lippmann’s images characteristics: а and г - dependence of image transmission spectrums on exposure amount at recording by radiation of helium-cadmium (442 nm) and nitrogen (337 nm) lasers; б and д – dependence of image density on exposure for the same wave length; в – dependence of image color on exposure logarithm (curve 1 – 442, curve 2 – 337 nm); dependence of half-width of transmission spectrums on exposure (1 – 442, 2 – 337 nm).]] Length of wave maximum reflection linearly depends on logarithm of exposure (image 2, в) what gives possibility to write <div> <p style="float: left; width: 90%; text-align: center;"><math>\displaystyle \lambda - \lambda_0 = k (\log{H_{max}} - \log{H})</math></p> <p style="float: left; width: 10%; text-align: center;">(1)</p> <p style="width: 100% /> </div> where λo - length of wave maximum reflection at high energy of exposure (wave length of saturation), H – energy of exposure, k – coefficient of proportionality which may be interpreted as coefficient of colors contrast. Image color change evokes change of its density (image 2, б, д). These dependences are similar to characteristics curve of nigrescence of simple registering mediums. Nevertheless photographic width of linear region is much smaller. Dispersion of experimental points is especially considerable in regions of high exposure that can’t be explained by measurement errors. We can suppose that dependence of image transmission in region of saturation has oscillating character as demonstrated for example on image 2, д. == Mechanism of image creation == Preparing plates to sensitizing they should be placed into water for a period of time (about one hour). As a result gelatin gets swelled and long protein molecules swivel in the way to create linear chains. It relates more to molecules on the surface of the layer than those which are deep in as they are less exposed to strength of adjacent molecules. There appears a heterogeneous hardening increasing from the layer surface to substrate. Superficial gelatin molecules forming linear chains can no longer perform work as they took favorable energetic position. Molecules deep in the layer have some amount of potential energy. Their interaction with each other and molecules of gelatin hardener prevents their forming linear chains. This hardening can be defined as value inversely proportional to work performed by molecules when processed in water. The layer is not hardened if molecules realized their potential. The layer is hardened If they didn't realize their potential energy when processed in water. Distribution of potential energy in the thickness of hardened layer may be presented in diagram form as demonstrated on image 3,a. Let’s consider processes taking place at hardening of exposed layers. Here we consider that photochemical transformations Cr (VI) to Cr (III) is realized according to model described in work [9]. At low exposure energies the number of photographic connections between the molecules created in bulge points is also small. Distribution of potential energy of molecules in hardened layer is demonstrated on image 3,б. At enduring processing in water besides hardening of layer in nodes of standing wave there may occur local gelatin dissolution. In other words hydrated molecules get relatively free changing their structure but can’t leave the layer because of hardenings in bulge. Work [10] and [11] describe that gelatin structure change at processing in water as well as at it’s drying. Therefore when processed by isopropanol change of gelatin structure in nodes and bulges are realized different ways. At considerable loss of water molecules don’t have time to return to initial state so they are forced to create a new molecular netting different from that which is created at simple freezing or slow drying. Gelatin density decreases in bulge points of standing due to growth of layer volume and increases in bulges due to change of structure under influence of formed Cr (III). As a result gelatin loses its elasticity. Increased period of interference structure can also be registered in the layer. Increasing exposure involves increasing of potential energy modulation in swelled layer. Number of isophased surfaces recorded in layer increases (image 3, в,г,д). Width of spectrum reflection and displacement to red region decrease but diffraction efficiency increases. Performance of black-and-white image can be explained by change of gelatin structure. Unstructured spots cause considerable light dispersion and get milk-white colored. == Discussing results == Unusual properties of Lippmann’s photos made on gelatin plates can be used for producing selective glasses as well as for receiving pseudocolor slides from black-and-white negatives and image processing and registration. Possibility of using Lippmann’s photos as selective glasses follows directly from image 2. Length of wave reflection and half-width depend on exposure value. At this coefficient of reflection reaches 99% that allows using such glasses in laser resonators, interferometers Fabri-Perot and also as beam dividers in hologram devices. [[Image:LippmannFig3.jpg|center|Image 3. Scheme explaining dependence of interference structure on value of exposure: а - distribution of hardening in swelled non-exposed layer; б, в, г, д – modulation of hardening in swelled layer depending on exposure.]] They cost less than interference dielectric glasses. There is also possibility of producing glasses of almost any size as well as distribution of spectrum characteristics within glass plane. Pseudocolor slides received from black-and-white negatives may be used for transmission of graphic information for example schemes, tables, diagrams. Slides can be projected at passing light by simple slider as well as at reflected light by epidiascope. It’s better to give preference to the second variant as color gamma is fuller and image contrast is higher then. At printing from black-and-white negatives value H_max and H in equation (1) can be presented as <center><math>\displaystyle> H_{max} = I_0 t (10^{-D_0})</math> and <math>\displaystyle H = I_0 t (10^{-D})</math></center> from this follows that change of color of Lippmann’s photo is linearly dependent on negative density. Last time in increasing frequency is used the idea of complex spacial distribution of different physical values by conventional colors for example at image digital processing [12]. This quality is inherent to Lippmann’s photos taking in consideration their nature. Lippmann’s coloring method has an advantage: such image may further be optically processed. Observing a pseudo-colored image through a light filter with gating line Δλ we can see details of initial image in the interval of densities ΔD. Details of interest of image may be marked by change of wave length of light filter. Diapason of densities may as well be marked by changing its half-width. If you make a photo of image observed through interference filter on a contrast photographic material you can receive image of lines of same density – equidensite. To illustrate this image of Jupiter was processed. For this the image of astro negative was printed with enlargement on dichromated gelatin plate. Then was made photo of received image through interference light filter with λ=640 nm and Δλ=90Å. Photo of initial image is presented on image 4, a. On image 4, б, в there are series of photos made at different angles of interference light filter incline that is at different λ and Δλ. You can see that even in conditions of incorrectly organized experiment (setting of wave length of light filter is realized by its incline) you can discover more details on received images than on initial negative. [[Image:LippmannFig4.jpg|center|Image 4. Marks of equidensite on Jupiter image: a – initial imprint of astro negative; б – photos of Lippmann’s image received using interference light filter at different angles of its incline at reflected light; в – the same but at passing light.]] At two-step process there inevitably occur distortion and noise at the first stage of registration. Grain on image 4, б is due to that of material on which the initial negative is registered. Therefore you can get much more information when processing Lippmann’s photos received at direct registration. Low sensitivity of dichromated gelatin plates does not allow direct registration of other astro objects except Sun. Direct registration of Lippmann’s photos is possible in biology. Radiation of ДРШ-250 lamp is enough for receiving images with enlargement 30-100x. Thus Lippmann’s photos received on dichromated gelatin plates using sources of monochromatic light have properties appreciably different from those of usual Lippmann’s photo. It’s related to properties of medium of registration. Period of fixed interference structure depends not only on length of radiation wave but also on its intensity. As a result there is a possibility to unambiguously transform light intensity to color. Simplicity of method of receiving Lippmann’s photos, possibility of using sources of low coherent length and high difraction efficiency offers a wide range of possibilities in practicing this method. In conclusion the author estimates as his pleasant duty to express gratitude to V.P.Sherstyuk, and L.E.Mazur for their important discussions, to V.A.Kaminskaya and L.E.Nikishyna for assistance in leading spectrophotometric measurement and to V.N.Dudinov for his kindly giving us astro negatives. == Literature: == # Lippmann G.C.R.// Acad. Sci. 1891.V.112. P. 274 # Kostylev G.D. // Letters in Technical Physics magazine 1976. T. 2. Edition 23.P. 1086. # Kostylev G.D., Ivanenko L.I. // Thesis report. IV All-Union conference “Photometry and its metrological equipment”. M., 1982. P. 119 # Sogokon A.B. // Thesis report. IV All-Union conference “Silverless and other unusual processes”. Chernogolovka, 1984. T. 1. Vol. 2. P. 125. # Sogokon A.B. // Thesis report. IV All-Union conference “Optical image formation and processing methods”. Kishinev, 1985. T. 1. P. 125. # Lin L.H. // Appl. Opt. 1969. V. 8. №5. P. 963. # Sjölinder S. // Photogr. Sci. and Eng. 1984. V. 28. №5. P. 180. # Nagorniy V.I., Chibisova N.P. // Successes of Physical Sciences. 1978. T. 19. P. 32. # Sherstyuk V.P., Dilung I.I. in “Fundamentals of optical memory and mediums”. Kiev: High School. 1982. Edition 13. P. 32 # Levi S.M., Suchkova O.M., Suvorin V.V. // Magazine of a scientific and applied photo and cinematography. 1984. T. 29. №4. P. 252 # Murzinov A.V., Moiseeva G.V., Stryukova E.G. and others // Thesis report at republican seminar “Applied holography”. Kiev, 1984. P. 49. # Usikov A. Y., Babichev A.A., Egorov A.D., and others // USSR Science Academy bulletin. 1977. №10. P. 47. Kharkov State University of Gorkiy 13.12.1985<br>Translated by Borozniak Evgeniy [[Category:Lippmann]] 25a90da80b216d1f54c12142d9ca60ebce0f74eb 0 835 1720 2013-05-08T01:48:34Z Admin 0 /* AgBr loading operation */ wikitext text/x-wiki Jeff Blyth This is a remarkably simple way of making a holographic recording material. This is the way that we make a lot of holograms in our lab, and we find it to be by far the easiest method for making holographic plates. In essence, we treat a glass surface to make it chemically 'sticky', we coat that with gelatin, and harden the gelatin with chromium or formaldehyde. Once we have the gelatin film we then soak into it a silver salt, and subsequently soak in potassium or lithium bromide to precipitate an ultra-fine grain precipitate of silver bromide. The bromide solution also incorporates a dye to make the plate photo-sensitive in the required wavelength range, and with addition of a little sensitiser we can produce by this method a holographic plate of quite high standard. A worksheet (dated Nov 2000) is given below. It gives results which have good diffraction efficiency and photosensitivity compared to ultrafine grain proprietary material. But this is for the fun of doing it all yourself and getting bright results. If you are particularly concerned about marks from bubbles, dust and blemishes then you may prefer to use the proprietary material. The material on this page is based on the following article, with some changes that we have made to our protocols since publication, and any differences between the original article and the text below are solely due to those differences. == A simple way to make silver halide hologram recording plates by Diffusion == By Jeff Blyth Institute of Biotechnology University of Cambridge Tennis Court Rd. Cambridge CB2 1QT Tel: 01223 334152 (fax: 334162) email: jeff@biotech.cam.ac.uk What follows is in the form of a worksheet based on the paper published in ''The Imaging Science Journal'', Vol. 47, pp 87-91, 1999. A text only version of the paper can be found on the Internet at http://www.holoworld.com/holo/paper.html or at http://www.holografie.com/paper.html. === The Basic principle === A coating of pure gelatin on a glass plate is treated with silver nitrate. The coating is then immersed in a bath of bromide ion and dye. This then precipitates extremely fine grains of silver bromide in the gelatin layer. === Materials === # Presubbed glass plates. You can use old holographic plates with the gelatin removed with the aid of household bleach. # Gelatin of bloom strength between 250 and 300 (e.g. 300 bloom from Aldrich cat no. 27,162-4). You can use culinary gelatin without any sugar or flavourings. # Ascorbic acid or Vitamin C. # Silver-nitrate. A 1N volumetric standard solution is a useful form. # Potassium Bromide # Chromium acetate. You can use chrome alum instead. # Dye(s) #* Pinacyanol Chloride for HeNe 633 nm exposure. #* 1,1-diethyl-2,2 cyanine iodide for 532 nm exposure. # Sodium hydroxide # 3-amino-propyltriethoxysilane (for new glass plates). === Concentration of Solutions === Quantities will need to be judged by you to suit your requirements. * Silver nitrate: 6% w/v in (DI) water (or the 1N volumetric standard solution diluted by 1 volume to 2 volumes DI water). * Stock dye solutions. (In practice, you would probably only need one hundredth of a gram to make up a few ml of these somewhat expensive dyes.) ** for 633 nm: 1 g / 1000 ml Methanol. ** for 532 nm: 1 g / 500 ml Methanol. * Potassium bromide: 4% w/v in 3 / 2 methanol / water (3% lithium bromide gives a finer grained hologram than the equivalent concentration of potassium bromide, however 4% potassium bromide works well). * Chromium acetate solution: 1% or Chrome Alum, 2% * Gelatin solution: 15% (see 2 paragraphs down). * Ascorbic acid: 1% solution in water, adjusted to around pH 5 with any alkali. === Preparation of plates === Glass plates usually need a pre-treatment step or the gelatin coating will peal off. You can use old holographic plates by simply giving them a 10 min. soak in neat domestic bleach solution and then rub off the old gelatin layer under tap water. After a final rinse in distilled water, no further subbing step may be required. However with new glass plates, I leave them soaking overnight in a 100% bleach (Domestos or Parazone). After the plates are dry I rub them over with a 1% solution of 3-amino-propyltriethoxysilane in acetone on a tissue until it has evaporated, and leave them in air to interact with the silane for at least two hours before coating. (The silane solution has to be freshly prepared for each batch of plates). === Preparation of coating solution for a 10 x 8 plate === Add 30 g gelatin to 170 ml cold distilled water and mark the liquid level on the beaker. Place beaker in a water bath and heat while stirring constantly until gelatin solution is between 60 and 70o C. Stir until all granules have cleared. Top up level to the mark. To remove skin and surface foam, pour through a fine mesh (nylon stocking works fine) into a preheated beaker. Then immediately proceed to next step: === Coating (by the old Victorian curtain method) === Hold the beaker in your right hand and with you left incline the presubbed glass plate (preheated to around 70oC) at an angle of about 30o to the vertical with its bottom edge in a clean tray. Pour the gelatin in a line about 1 cm from the top of the plate. The pouring rate must be continuous until the furthest edge of the plate is reached. (You may have to accept the tendency of the coating to not completely cover the lower part closest to the furthest edge.) Lean plate against something for a few minutes while coating gels. Run a knife along thick layer at the bottom to free plate rather than risk tearing the delicate coating. (Since no hardener is involved yet the gel can be readily scooped up and re-coated if you are not satisfied.). Put plate in cold solution of chromium acetate for 1 minute. Shake off drips and then (without washing away that salt) blow plate with cold air until dry. Once the layer is dry leave the plate to complete the chrome hardening effect overnight in a warmer. (Preferably at around 60oC for several hours). Rinse the hardened plate in DI water and dry in a warm air flow. If you want to cut plate up for the next step then after scoring the glass on the back and cracking it, it is best not to pull sections apart before running a scalpel blade along the gelatin side first so that it is cut and not torn apart. Alternatively a Meyer bar can be used. About 7 turns per cm. === AgBr loading operation === # For a 5 x 4 plate place approx 3 ml 6% silver nitrate solution in the centre and at once squash it with a clean flat cover plate (preferably transparent plastic so that you can see the air bubbles are squeezed out). Leave for 3 minutes. Safelighting is not strictly necessary here but white lighting should be subdued. # Remove cover plate and immediately remove the excess silver solution on its surface by gently brushing over the plate with a soft squeegee (windscreen wiper blade). # Blow dry plate with cool air. Once dried, the plates can be stored for a short while in a cool, dry, dark location until needed. # Under safelight conditions, add 2.5 ml of dye solution per 100 ml of potassium bromide solution, add about 0.5 ml of 1% ascorbic acid solution (this is the same solution as is used in the final sensitizing bath) agitate the bath and plunge plate in while maintaining the agitation for about 2 minutes (although with softer gelatin this could be reduced to 60 seconds, otherwise unacceptable grain growth can occur. Expect to spend a little time optimising this step for your own application). This solution can be re-used a number of times, until such a point as the dye starts to come out of solution or the brightness of the resultant holograms seems to be diminished; the dye used for 532nm exposures (see above) is far more re-usable. # Rinse well under running tap water (any AgBr only on the surface can be removed by gently rubbing with ungloved finger.) Plates usually come out this bath beautifully clear under the green safe light, without any surface deposit. # Sensitizing bath step #: The plate can be immersed for 1 minute in 1% ascorbic acid solution adjusted to pH 5 using a little sodium carbonate or hydroxide. Alternatively, the well known triethanolamine pre-swelling technique can be used with the advantage of increased brightness at a shorter wavelength. (Prolonged settling period may then be necessary however to avoid creep while the exposure is being made). After exposure the plate is then developed as per the first part above. 7260df0259b738716a537b3cf10576570c271140 0 204 1624 256 2013-05-08T02:36:12Z Admin 0 /* General Notes */ wikitext text/x-wiki [[Category:DCG]] Dichromated gelatin is a light-sensitive material made from gelatin (including ordinary food gelatin such as Knox) and a small amount of either ammonia dichromate or potassium dichromate. <br> == Useful Information == [[A Beginner's Approach to DCG Holography|A Beginner's Approach to DCG Holography]]<br> [[Dichromated Gelatin Chemistry|Dichromated Gelatin Chemistry]] <br> == Notes == The basic formula for dichromated gelatin is water plus gelatin plus either ammonium or potassium dichromate. The amounts of each ingredient influence the characteristics of the result. Exposure energy requirements, color shift, emulsion thickness, etc., are all impacted by the formulation. It is convenient, then, to have a standard for formula reference. Richard Rallison promoted using a system of three numbers to describe a formula—grams of dichromate, grams of gelatin, and grams (milliliters) of water. For example, 8-30-250 would be the notation for a recipe consisting of 8 grams ammonium or potassium dichromate, 30 grams of gelatin, and 250 grams of water. To make comparisons among formulae, the gelatin number is always 30 in Rallison’s notation. The three numbers can be scaled equally up or down for producing different quantities of emulsion. (Personally, I usually scale the numbers to 7.1 grams of gelatin, 7.1 grams being the mass of gelatin in quarter-ounce packet of Knox brand gelatin.) == Thickness and Bandwidth == The ratio of gelatin to water affects the viscosity of the emulsion, and that in turn affects the typical thickness of emulsion on the glass plate. The thickness influences the bandwidth of the final hologram. Rallison reported the following results for emulsions applied by 80 RPM spin coating method: {| border="1" align="center" cellpadding="10" |- ! align="center" scope="col" | '''Formula''' ! align="center" scope="col" | '''Thickness''' ! align="center" scope="col" | '''Bandwidth''' |- | align="center" | xx-30-350 | align="center" | 5 – 6 µm | align="center" | 50 – 150 nm |- | align="center" | xx-30-250 | align="center" | 8 –9 µm | align="center" | 10 – 50 nm |- | align="center" | xx-30-200 | align="center" | 10 – 12 µm | align="center" | 10 – 50 nm |- | align="center" | xx-30-150 | align="center" | 20 – 24 µm | align="center" | ~8 nm |} <br> == Replay Color Shift == The ratio of dichromate to gelatin influences the color shift. The following table has typical values for exposures taken at 514 nm: {| border="1" align="center" cellpadding="10" |- | align="center" scope="col" | Formula | align="center" scope="col" | Color Shift |- | align="center" | 3-30-xxx | align="center" | 630 nm |- | align="center" | 6-30-xxx | align="center" | 590 nm |- | align="center" | 10-30-xxx | align="center" | ~514 nm |} == Exposure Sensitivity == My personal guess at typical exposure requirements for the basic recipe 8-30-300 emulsions. {| border="1" align="center" cellpadding="10" |- | align="center" scope="col" | '''Wavelength''' | align="center" scope="col" | '''Exposure''' |- | align="center" | 405 nm | align="center" | 5 mJ/cm² |- | align="center" | 442 nm | align="center" | 15 mJ/cm² |- | align="center" | 475 nm | align="center" | 40 mJ/cm² |- | align="center" | 488 nm | align="center" | 60 mJ/cm² |- | align="center" | 514 nm | align="center" | 125 mJ/cm² |- | align="center" | 532 nm | align="center" | 200 mJ/cm² |} [[Image:DCGsensVwav.png]] A great many factors may have a dramatic effect on sensitivity, notably humidity and temperature, so the above table is only a point of reference. Sensitivity also varies inversely with the dichromate concentration—halving the amount of dichromate would double the exposure requirement, for example. == Weird DCG Recipes == === 3.6&ndash;30&ndash;467, Chromium Acetate, Ethanol === Markova, Nazarova, and Sharlandjlev, “Control of the Spectral Position of DCG Reflection Holograms,” ''Institute of Optical Materials and Technology''. *64.3 g gelatin, Bloom strength of 210 *7.71 g ammonium dichromate *0.64 g chromium acetate *65 ml C₂H₅OH (ethanol) *Distilled water to make 1000 ml Plates are coated with the solution at 50°C by doctor-blade method to 20 µm. === 5&ndash;30&ndash;200, Ammonium Nitrate === Bahuguna, Beaulieu, and Arteaga, “Reflection display holograms on dichromated gelatin,” ''Applied Optics'', volume 31, issue 29 (1992). *2.5 g of ammonium dichromate *1.5 g of ammonium nitrate *100 ml of distilled water, heated to 70°C *15 gm of USP grade Baker's gelatin (125 bloom strength) powder slowly added while stirring Spin-coat at 100 rpm the still ~70°C emulsion for 90 seconds under hot-air gun. Dry vertically in a dark box. Plates are ready after about 6 hours. Sensitivity was reported as 100 mJ/cm² at 488 nm. [In Rallison’s Thick DCG paper, he associated ammonium nitrate with hardening.] === 4.5&ndash;30&ndash;500, Ammonia === Coblijn, Alexander B., "Theoretical background and practical processing techniques for art and technical work in dichromated gelatin holography", ''SPIE Institute Series'' Vol. IS 8 (1990). *100 g water *6 g gelatin *0.9 g ammonium dichromate *2 ml ammonia 35% (added last) Household ammonia is typically 5-10%. [Presumably, the ammonia inhibits the dark reaction.] 837126278de0a3be15ef3a9825259876b36adc70 0 820 1644 2013-05-08T03:16:01Z Admin 0 /* Overview of the Process */ wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. The are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. Epoxy is normal sealant. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. [[Category:DCG]] [[Category:Beginner]] 4792233bfbc9b98a576a2a36e5f14facb53c28f1 0 212 1646 272 2013-05-08T03:18:08Z Admin 0 wikitext text/x-wiki Dichromated Gelatin (DCG) is one of the brightest media for recording holograms. It is used in art as well as [[HOE|HOE]] fabrication. *[[A Beginner's Approach to DCG Holography|A Beginner's Approach to DCG Holography]] by John Pecora *[[A Simple DCG Recipe|A Simple DCG Recipe]] by Joe Farina *[[G307 DCG Formula|G307 DCG Formula]] Increased overall sensitivity and to 514nm - 532nm *[[MBDCG|MBDCG]] *[[DCG Theory|DCG Theory]] *[[Sealing DCG Holograms|Sealing DCG Holograms]] *[[The Mechanics of Gelatin and the DCG Process|The Mechanics of Gelatin and the DCG Process]] *[[DCG Variables|DCG Variables]] *[[Coating Methods|Coating Methods]] *[[Troubleshooting DCG|Troubleshooting DCG]] d32671bc2a63e12071dbf0dbe62fe019b34557c9 0 1 1752 1349 2013-05-08T03:20:40Z Admin 0 wikitext text/x-wiki Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms. {{Note | This wiki is undergoing a slow and painful face lift. Please bear with us.}} [[File:Olympic.jpg|250px|right|Hologram by Tom B. The Gallery has a stereographic pair version.]] *'''[[Gallery]].''' Great examples of success, failure, and experiments. *'''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. *'''[[Beginner's Corner]].''' Basic information for getting a start in holography. *'''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. *'''[[Equipment]].''' Things used in making holograms, including some '''[[Homemade Equipment]]''' items. *'''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. *'''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. *'''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. *'''[[History of Holography|History of Holography]].''' The timeline of the people and technology. *'''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! *'''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. *'''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. *'''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. *[[Archives|Archives]] *'''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). d4d1f26b695b9c9f21d4e4b47cfc1067cefe99ec 1 2013-05-12T00:58:21Z MediaWiki default 0 wikitext text/x-wiki '''MediaWiki has been successfully installed.''' Consult the [//meta.wikimedia.org/wiki/Help:Contents User's Guide] for information on using the wiki software. == Getting started == * [//www.mediawiki.org/wiki/Manual:Configuration_settings Configuration settings list] * [//www.mediawiki.org/wiki/Manual:FAQ MediaWiki FAQ] * [https://lists.wikimedia.org/mailman/listinfo/mediawiki-announce MediaWiki release mailing list] b7a3846f2c55072191227d89a3204fe379288fee 0 826 1684 2013-05-10T14:54:27Z Admin 0 wikitext text/x-wiki == Silver Halide Films and Plates == === Workin' out with Irena === {| |- | Tom B.: Same plates and technique as usual (BB-640, 6% TEA, lit for photo with OptiLed amber from about 1.5 m). The pics didn't come out as well this time, but good enough. The fringe pattern under the models is intentional - I calculated a mickey-mouse model of spherical wavefront interference and printed it out on cardstock as a background, but alas it moved a bit so it's dark under Irena's hand. [[File:Olympic.jpg|400px]] Here is a stereoscopic pair photographed from the hologram. Look through the image to get the two halves to merge into a single image. [[File:Olympic_stereo.jpg|400px]] More of Tom B.'s work is show-cased at http://members.shaw.ca/holopix/My_holograms.html, complete with a chronology of his ever-improving efforts. |} === My First... === {| | PeterZ: This is my first reflection hologram using Integraf holokit, with PFG-01. Exposure time was 25s, distance between laser and plate 37 cm. Not very good photo. I'll do another one using polarizing filter and camera with manual focus. [[File:PeterZ_first.jpg|400px]] |} == Litiholo Kit == === Simple Transmission of Car === {| |- | Transmission hologram by Arturo with Litiholo kit. [[File:Arturo_Liti_car1.jpg|250px]] [[File:Arturo_Liti_car2.jpg|250px]] |} == Dichromated Gelatin == === Mermaid === {| | Colin Kaminski: This is a 4x5" dichromated geletin reflection H2 hologram that Dinesh, Joy and I made at their lab in San Diego. Here is a link to their work: http://www.tripletake.com. I helped a little but really the sucess of this image was the result of their skills which they were very generous about teaching me. [[File:Kaminski_mermaid.jpg|400px]] |} === Musical Angel === {| |- | John Pecora: On the left, 488 nm, 30 second exposure, fixer, water, alcohol. On the right, also 488 nm and 30 second exposure, then water for 25 seconds, then fixer, water, alcohol. Both exactly the same except the water prior to fixer soak. If you look on the right near the head in the white hologram you will see a type of whiteness and it starts to blur into the angels head on the white hologram. It seems to be where the emulsion is thin. The emulsion actually seemed to crystalized. It's not that is it cloudy but it reflects the light off the emulsion like a white haze. The more more of an angle the replay light the more diffusely reflecting the haze is and the further into the hologram it moves (all the way over to about half way across the head where it is blurry). Also what I noticed is the hologram on the left, when dried with the hot air just dried and got brighter and shifted colors. The one on the right exhibited that white crystalization (not cloudy) that then cleared up and went away to yield the hologram. [[File:JohnFP_AngelMusic.jpg|400px]] |} === Compass 215M Test === {| |- | Dave Battin plays with his Coherent 215M running at just under 30 mW. This hologram was a 6 minute exposure using one concave mirror, rapid fix. and ''dip sensitizing method''. The dip sensitizing method involves the following: * Coat gelatin onto glass and allow to harden. * Dip hardened plates into solution of AmDi (15 g), H₂O (500 ml), and soapy water (10ml). * Allow to '''air dry'''. * Expose. [[File:Battin_215M.JPG|400px]] |} === Two Color Test === {| |- | Combined red and green beams by Joe Farina. [[File:Farina_DCG_marbles.JPG|400px]] |} === Two Color Figures === {| |- | Joe Farina: These were done with Jeff's MBDCG formula, except that boric acid was used to adjust the pH, and Rhodamine 6G was used as the additional green sensitizer. The exposure was a combined 532/633 beam, with 14mW for 532 and 20mW for 633, measured after the spatial filter, the holograms are simple SBR Denisyuk. Plates are about 5 X 5 inches, and the exposures were around 20 minutes. One of the figures was painted with a few colors (very crudely), and the other figure was painted silver. The silver-painted figure helps me to get a better grip on whether the hologram (as a whole) is more narrowband or broadband. The plate on the right has a serious flaw (but also the best color reproduction) because there is a patch across the lower faces and upper chests of the two figures. This seems to be where the emulsion overheated in the oven. (I made a mistake by laving the glass directly on the inner floor of a homemade oven, I will correct that next time.) The colors came out fine. The outer robe is green, the inner garment is red, the scroll is white, the skin tone is tan, the hair is dark brown, with some lighter brown areas. I'm surprised the scroll came out so white. These two wavelengths (532 and 633) seem to be capable of reproducing a great many colors, but of course anything containing blue won't show up. I'm confident that this exact system will work very well if blue is added, for full color. [[File:Farina_DCG_figures1.jpg|400px]] [[File:Farina_DCG_figures2.jpg|400px]] [[File:Farina_DCG_figures3.jpg|400px]] |} === Little MBDCG Holo === {| |- | Hans: Here is a sample of a MBDCG that I just made with my adjustments to the original MBDCG. Due to temperature/moisture in my garage, I would never have been able to do this in my garage with classical MBDCG as was invented by Jeff Blyth because of fading (crystallizing) of the MB in the plate. Exposure time was 5 minutes with a TEC controlled laser diode. The plate was processed as follows: * First a long wash (10 minutes) in cold water to wash out the chemicals. * A swelling bath at 26C. I found that for thick coatings, this bath needs to be at least one minute. Otherwise, dim areas will appear on the hologram. * 35% IPA at 25C, two minutes * 70% IPA at 25C, two minutes * 99% IPA at 25C, three minutes I use no fixer. Remember that in classic DCG, the fixer is needed to convert the Cr(V) to Cr(III). It is the Cr(III) that hardens the fringes in the gelatin. With MBDCG it is the Methylene Blue that does that job. Cr(VI) is converted directly to Cr(III) upon illumination, and thus eliminating the need for a fixer. In previous experiments I found a great benefit in using a hardener before the swelling baths. But because my hardener was getting old so fast, I started to experiment with post exposures. I found the effect to be similar. I prefer the post exposure method over a hardening bath because it cancels out two big variables: Temperature of the hardening bath and age of the hardening chemicals. With a post exposure there is only one variable: Post exposure time. Experimentally, a post exposure time of 1/7 of the normal exposure time seems to work fine. I just wiggle the plate in the expanded laser beam at about the same distance where the plate was when the hologram was exposed. I have not found a little difference in bandwidth between post exposed plates and chemically hardened plates. Post exposed plates indeed are a little bit more broadband. But that to me is a benefit. [[File:Hans_NewFormula1.jpg|400px]] |} 146ed7c624bd2cd5541610727a89249f4ff25d8d 0 836 1724 2013-05-11T01:35:04Z Admin 0 wikitext text/x-wiki Please note that these pages are currently in the process of being placed online. Some images and formatting from the original published version may still be missing. * [[Control of DCG and non silver holographic materials]] * [[Polarization properties of gelatin holograms]] * [[Blazed Binary Optics, From PC to Plastic]] * [[Media characteristics, tables and plots]] (lots of images) * [[Phase materials for HOE applications]] [[Category:Rallison]] 7a29257397e8075665e8284ea4fd895a41a9f840 0 832 1714 2013-05-11T01:36:57Z Admin 0 wikitext text/x-wiki [[Media:Holotool.exe|Holotool.EXE]] is a self extracting program that contains four DOS executables and three pcx drawings totaling just 115 kbytes when expanded by running Holotool. It is probably best to run it in it's own directory, so identifying the individual programs is easy. The programs included are as follows: '''EXPAND2.EXE''' is a menu driven program that asks you for the playback and construction wavelengths, the playback and construction bulk index of refraction of the recording media, the external angles for playing back either a transmission or reflection HOE or hologram and the thickness change multiplier expected from your film. The output is the internal Bragg angle, the spatial frequency and the internal and external construction angles for both before and after expansion or shrinkage of the film. The program toggles through remembering what you did and allowing changes to be made to quickly try out a lot of configurations to find out what will probably work and what will not. '''TIR2.EXE''' is just like Expand2 except that the second angle it asks for is the internal playback angle, which allows you to design total internal reflection (TIR) HOEs or edge lit holograms. The output includes a prompting for a best angle prism to index match to the film substrate and allows you to input any angle prism you may have and then outputs an angle for the non prism side and one for the ray entering the prism if a reflection geometry results or two ray angles measured off the normal to the prism in the case of a transmission outcome. TIR fringes hover around 45 degrees of Brag tilt and are especially hard to make correctly so this is the most valuable of the utilities I use myself and the newest of the three programs. '''TIR2.PYW''' (not part of the holotools package) is a graphical version of TIR2, written in [http://www.python.org/ wxPython], for Windows 95/98/NT and UNIX/Linux. To use this program, you will need to download the [[Media:tir2.pyw | tir2.pyw]] program file and the [http://www.python.org/download/download_windows.html Python Interpreter] and the [http://www.wxpython.org/download.php wxPython toolkit]. After installing the wxPython software package, the TIR2.PYW program file will be executable. To learn more about wxPython, go to the [http://wxpython.org/ wxPython home page]. ''Note:'' tir2.pyw is a work in progress. Please send all suggestions or bug reports to rdr@ralcon.com. '''CHIRP.EXE''' is an older Fortran program that models holographic or dielectric mirror stacks using a quarter wave model or Kogelnic's approximation, you get to choose. The inputs are bulk index, center wavelength, film thickness, average expected index modulation, absorption of the holographic film during exposure in percent (gradient), percent change in fringe spacing as a function of depth (chirp) and wavelength range to scan symmetrically around the center wavelength. The outputs are first a plot of index modulation as a function of depth then a plot of density versus wavelength and if you choose to save the file when prompted you can retrieve it with CHIRCALL.EXE and display and print an amplitude reflection plot to use to match up with a spectrophotometer output of a real mirror. This program is useful for measuring the index modulation of a film when things are not linear or uniform as is true for most recording media. There are three GIF files, [[Media:expand2.gif | EXPAND.GIF]], [[Media:tir2.gif | TIR2.GIF]] and [[Media:nchirp.gif | NCHIRP.GIF]] that give sign conventions and further instructions for using their respective namesakes. These are easily read and printed from Paintbrush and many other programs including word processors. For those that prefer to customize their software, the source code for the two C programs is also available by email. [[Category:Rallison]] 9215828f9683a08a0e1e6195a5d16c765c8de873 0 837 1726 2013-05-11T01:43:38Z Admin 0 Created page with "8501 S 400 W<br> Paradise, UT 84328 == From Salt Lake City to Logan == [[File:map_big.gif]] * First thing is to find I15 (shouldn't be hard). * Follow it to exit 362 (Brigham C…" wikitext text/x-wiki 8501 S 400 W<br> Paradise, UT 84328 == From Salt Lake City to Logan == [[File:map_big.gif]] * First thing is to find I15 (shouldn't be hard). * Follow it to exit 362 (Brigham City) == From I15 Exit 362 to Paradise == [[File:map_canyon.gif]] * From I15 Exit 362, head into Wellsville Canyon. * Not long after exiting the canyon there will be an exit marked "Mt. Sterling." * The exit is easy to miss. If this should happen, try for the Hyrum exit. * Following either exit (or even going into Logan) will lead to Highway 165. * Follow HW 165 South until there are only trees on the right and hills on the left. == Getting to Ralcon Dev. Lab from Paradise area == [[File:map_paradise.gif]] * From HW 165, either: *** Get off on 7800 S (hidden in the trees) *** From westbound on 7800 S turn left. *- OR *** Follow the road to 8700 S (Car Service) *** From westbound on 8700 S turn right. ''Last modified on 1/03/2005'' [[Category:Rallison]] 786ee39ba31bb27086aee7fd9b24fc4374460aaf 0 838 1742 2013-05-11T01:53:32Z Admin 0 Created page with "* [http://www.noao.edu/ets/vpgratings/ volume phase gratings] '''''Lidar links:''''' * [http://q.eisl.harc.edu/~www/ Houston applied Research lidar] * [http://bll.gsfc.nasa.gov…" wikitext text/x-wiki * [http://www.noao.edu/ets/vpgratings/ volume phase gratings] '''''Lidar links:''''' * [http://q.eisl.harc.edu/~www/ Houston applied Research lidar] * [http://bll.gsfc.nasa.gov/ Boundary Layer Lidar] * [http://rsd.gsfc.nasa.gov/912/code912/raman.html Scanning Raman Lidar] * [http://virl.gsfc.nasa.gov/lazer/index.html Holographic Optical Telescopes and Scanners] * [http://bll.gsfc.nasa.gov/harlie/ HARLIE] * [http://harlie.gsfc.nasa.gov/ HARLIE] (Holographic Airborne Rotating Lidar Instrument Experiment) '''''Misc links:''''' * [http://www.familysearch.org/ Dead People] (geneology) * [http://www.geocities.com/TheTropics/3053/part103.html FAR part 103] * [http://tycho.usno.navy.mil/cgi_bin/timer.pl Time] * [http://www.wasatchphotonics.com/index.html Wasatch Photonics] * [http://www.i-glasses.com/ I-Glasses] * [http://www.terabeam.com/ Terabeam] ''Last modified on 9/13/00'' [[Category:Rallison]] a97696fa92fbaa40e0cd4ed378445051ddd43e02 0 839 1758 2013-05-11T02:37:56Z Admin 0 wikitext text/x-wiki [[File:deltan.gif|center|Exposure vs. density]] {| border=1 |- | Material || DCG || DMP128 || PVK |- | Sensitivity (mj/cm²) || 2-100 @ 442-532 || 30 @ 633-694 || 20 @ 488-532 |- | Approximate available index mod (Delta n) || 0.25 || 0.20 || 0.20 |- | Max O.D. attained in notch filters || 5 || 4 || 2.5 |- | Useful thickness range (microns) || 5-25 || 7-15 || 5-10 |- | Available Spectral Bandwidths (nm) || 10-150 || 10-100 || 20-100 |- | Playback compared to record wavelength || red shift for broad and/or blue shift for narrow | variable blue shift || red broad/blue narrow |- | Minimum recommended protection || 40 mil glass and epoxy || 4 mil Aclar || 4 mil mylar |- | Resistance to water || poor || fair || excellent |- | Familiarity or experimentation period || 13 years || 6 mo. || 6 mo. |- | Number of samples made || 100 || >200 || >50 |} Notch filters or conformal reflectors where made in each of these materials and also in some of Dupont photopolymers. The dupont products have typically smaller bandwidths and lower maximum available index modulation, but the sensitivity is now in the 10 to 20 mj/cm*cm range and the sensitometric curves are similar to the DMP 128 curves in shape. The migrating photopolymers can not be over exposed in the reflection configuration and are fixed by white light or UV flood exposure or over exposure to laser light. == DCG #1 BB == [[File:pg29-1-l.gif|center|DCG1 BB]] {| border=1 |- | n = 1.560 || nl = 0.180 || d = 9.00um || lambda center = 550.nm |- | colspan=4 | Scan from 325.000 nm to 775.000 nm |- | colspan=2 | Minimum %T = 0.0365 || colspan=2 | Maximum %T = 99.9966 |- | colspan=2 | Multiple layer dielectric theory || 38.00% Damping || 9.00% Chirp |} [[File:pg29-1-r.gif|center|DCG1 BB]] {| border=1 |- | n = 1.560 || nl = 0.180 || d = 9.00um || 38.00 % Damping, 9.00 % Chirp |- | colspan=4 | Scan from 325.000 nm to 775.000 nm |- | colspan=2 | Maximum OD = 3.437 || colspan=2 | Minimum OD = 1.479E-05 |} == DCG #2 MB == [[File:pg29-2-l.gif|center|DCG2 MB]] {| border=1 |- | n = 1.560 || nl = 0.140 || d = 9.03um ||lambda center = 525.nm |- | colspan=4 | Scan from 300.000 nm to 750.000 nm |- | colspan=2 | Minimum %T = 0.0030 || colspan=2 |Maximum %T = 99.5860 |- | colspan=2 | Multiple layer dielectric theory || 36.00% Damping || 3.00% Chirp |} [[File:pg29-2-r.gif|center|DCG2 MB]] {| border=1 |- | n = 1.560 || nl = 0.140 || d = 9.03um || lambda center = 525.00nm |- | colspan=4 | Scan from 300.000 nm to 750.000 nm |- | colspan=2 | Maximum OD = 4.522 || colspan=2 | Minimum OD = 1.802E-03 |- | colspan=2 | Multiple layer dielectic theory || 36.00 % Damping || 3.00 % Chirp |} Reflectors in 10 microns of DCG can be processed to have all of the above characteristics. The time, temperature and alcohol concentrations all affect bandwidth and density. == Refractive index change as a function o fdepth for 901 points == [[File:pg30.gif|center]] Model of chirp in spacing and gradient in delta n Broadband effects in DCG, DMP 128 and other materials arise from processing induced chirps in the spacing of the fringe planes much like the variable spacing and amplitudes shown here. Absorption of light during exposure contributes to a broader bandwidth by introducing an exposure amplitude gradient in the index modulation through the depth of the film. The processing gradient caused by the diffusion of developers or solvents into the film may enhance or reduce the gradient depending on whether the film was exposed film side up or film side down (especially in a single beam configuration). This explains why two single beam reflection holograms can appear to be very different in color and bandwidth if one was shot film side up and the other film side down. This plot and the previous plots of amplitude and density and the following plots for DMP 128 were modelled using a program that takes into account a linear chirp in spacing and an exponential gradient in refractive index modulation resulting from absorption of the exposure light. A newer version will plot curves that have nonlinear chirps and generates shapes that more closely match those obtained in a scanning spectrophotometer. == Effects of gradient in n on polarizer performance == [[File:chirp.gif|center|Chirped DCG Reflector]] ''most S light reflected in high delta n region''<br> ''spectral bandwidth is approx. 150nm'' Another way to view the chirp in a plain mirror is shown above where the additional effect of a varying average n through the film is also seen. The fringes near the surface are seen to have wide spacings reflecting Red light with high efficiency because the delta n is highest there. As light travels deeper in finds shorter paths, higher n and lower delta n. The changing n makes a difference in the internal reflection angle, but not the external. This reflector acts as an efficient polarizer for green light because no P polarized light can be internally reflected. It is quite good at other colors as well. [[File:pg34.gif|center|Reconstruction wavelength in nm]] '''Dicromate as % of gelatin by weight''' The Color that DCG reconstructs at can be controlled by how much sensitizer and other dissolved solids are contained in the film before exposure. The sensitizer is washed out and the film loses from 5 to 30% of it's original thickness but processing causes 10 to 50% swelling, depending on how thick the film is and how hot the solvents are and on ph and an time and prehardening among other things. [[File:pg35.gif|center]] Color control can be done easily and repeatably in films of 8 to 20 microns by simply controlling the concentration of dichromate and keeping all processing steps conservative and constant. The graph above is a rough guide to reconstruction colors as a function of two popular exposure wavelengths and dichromate concentration. These numbers are typical of 8 to 10 micron films processed for 1 to 2 minutes in fixer followed by 30 seconds in each water and alcohol bath. The alcohol was about 49 deg C (120 degrees F), as usual processes vary with gelatin selection and condition. [[File:spindev.gif|center|Spin coating]] '''Spin coating at 70 to 100 RPM The thickness of a DCG film may be controlled with wire thickness and water concentration when using a meyer bar or may be controlled with rotation speed and water concentration on a simple turntable made from an old phonograph player. The graph above gives approximate thickness of a standard mixture of 10 grams of dichromate and 30 grams of gelatin in from 400 to 100 ml of water at 60 degrees C. 40 to 50 micron films are spun at 70 RPM, most others are at 100 RPM. Films over 20 microns thick stick to glass better if they are baked for at least 1 hour at 150 deg F and in water saturated air. [[File:spincoater.gif|center|Spin coater]] '''Spin coater''' [[File:dcgtime.gif|center|Process time in minutes]] Processing is either a cool single phase low modulation method or a warmer 2 phase higher modulation process. In between is an unstable region that will produce blotchy reflection holograms where the color difference between blotches is on the order of 50 nm or so. The unstable region is also defined by alcohol/water concentration and again depends on the source and condition of the gelatin. It is sufficient to know that it exists and that it may be avoided by changing temperatures or specific gravities up or down. Film thickness also strongly affects the choice of processing. Thin films are best done in such a way as to maximize the delta n and this is done with hot baths and short process times. Thick films require low delta n to take advantage of the angular and spectral selectivity available in thick films and are best processed at or near room temp for long times in each bath. The plot above is a guide to a starting point, the dots are regions we have worked in. ''Last modified on 6/3/99'' [[Category:Rallison]] 21a5a9b7cd92b01473e85f70bb35d6a69c9b6fa4 0 840 1770 2013-05-11T03:09:19Z Admin 0 /* IMPLICATIONS OF A LOW N IN DCG DEVICES */ wikitext text/x-wiki Dichromated gelatin (DCG) exhibits variable changes in effective refractive index (n) from 1.54 before exposure to less than 1.25 as it expands during processing. This aerogel like effect causes aberrations in diffractive optics and Kogelnik's theory predicts strong polarization separation in gratings at many different angles other than 90 degrees. The diffraction efficiency of both S and P polarizations at any angle is dependent on the product of thickness and index modulation while the angle inside the medium is dependent on n. We investigated predicted conditions where only one polarization would be diffracted and subsequently proved n varies from about 1.4 to 1.2 after processing and depends on the film thickness and processing procedures. Transmission gratings made at angles from 36 to 66 degrees were fit to mathematical models as proof of the phenomena,some performed with extinction ratios greater than 100:1. We were also able to demonstrate a similar range in conformal reflection structures and to design a novel polarizer. The calculation of exposure geometries for display holograms becomes more accurate when index change is included in the formulas but some results remain hard to explain. ==REDISCOVERY OF A LOW INDEX== Several years ago we had verified by modeling notch filters that Shankoff was correct in claiming that dichromated gelatin could have an index modulation, delta n, of as much as .26. In 1977 Meyerhofer argued that this may imply that the bulk index, n, could drop as low as 1.27 and that the large delta n and corresponding low n was the result of forming small distributed voids of air in the gelatin. He offered no proof or experimental evidence of the low value and made no comments pertaining to the implications and as far as we know it has been overlooked and undervalued ever since then. We were made aware of Meyerhofer's conclusions and publication, which was on my bookshelf for 10 years, only after we had tabulated hundreds of data points that appeared to support values of n as low as 1.2. We were attempting to make a polarization splitter at an angle that should have worked if the n were near 1.5, in desperation we tried incremental angles above and below the calculated angle. We made hundreds of gratings and carefully plotted the S and P efficiencies as a function of delta n in the region where the S first goes to zero. The design we were concentrating on depended on an internal diffraction angle of 30 degrees, which of course depended strongly on n for a grating structure with fringes normal to the surface. The experimental data we gathered is shown graphically in figure 1. SPIE vol 1667, San Jose, CA. Feb 13 (1992)<br> [[File:pg15.gif|center|Figure 1]] '''Figure. 1.''' Efficiency of S and P as a function of delta n for angles between 36 and 50 degrees, experimental results in 7 micron films, P curve sections are drawn over a common minimum S value. ===Transmission proofs of a low effective n=== The data we had in hand indicated by modeling on a mathcad template that the index was around 1.26 and we eventually modeled 4 other configurations that could be used to demonstrate a low n or measure it more closely. Each model was derived from Kogelnik's one dimensional coupled wave model of either transmission or reflection gratings. Figure 2 is the model that best matched to the first experimental data in figure 1, the thin lines are computed plots and the heavy sections indicate where supporting data was obtained by making and testing at 38 degrees until both crossing points were found. The crossing points had to be nearly equal for further evidence of being at the right angle. Figure 3 is a simple proof where the internal angle will be 90 degrees and no P can be diffracted at any value of delta n. This proof has a catch to it because the value of n varies with the value of delta n so some p light actually will be diffracted at low values of delta n where n is still high. The range of delta n we tested pushed n low enough to nearly zero out the P light as S went through 2 maxima at 64 degrees external. Figure 4 is an accidental proof that we modeled after the fact as we reached modulation saturation while testing at 48 degrees. At an external angle of 48 degrees we made a few gratings that diffracted virtually all of both polarizations which models to an n of about 1.27. Some of the data points in figures 2 thru 4 were taken from 7 micron films and also in 5 micron films which because of gradients behave more like 4 micron films. The positions of maxima and minima remained the same for both films. [[File:pg16-1.gif|center|Figure 2]] '''Figure 2.''' Computed model with overlay of normalized experimental data points taken from 35 samples. [[File:pg16-2.gif|center|Figure 3]] '''Figure 3.''' Computed model for 90 degree turn internally with some data points normalized and overlaid. [[File:pg16-3.gif|center|Figure 4]] '''Figure 4.''' Computed model matching experimental results of S and P both near 100% in 2 or 3 samples. ===Reflection proofs of a low n in DCG=== Figure 5 shows what turned out to be the most conclusive and easiest to demonstrate proof. Conformal reflectors have an angular spectral bandwidth that varies widely with n. The first plot shows this dispersion curve for n = 1.54 and a zone where we actually measured various reflectors that had values of n ranging from 1.4 to 1.27. The small straight horizontal line is the locus of external incident angles where no P light is reflected and runs from 64 to about 85 degrees. [[File:pg17-1.gif|center|Figure 5]] '''Figure 5.''' Computed angular dispersion curves for conformal reflectors with bulk n ranging from 1.54 to 1.27 overlaid with measured data. [[File:pg17-2.gif|center|Figure 6]] '''Reflection: Internal angles remain constant''' '''Figure 6.''' Graphical representation of the behavior of a reflector if original exposure conditions prevailed and below it the behavior due to low n and expansion of the film. Figure 6 illustrates graphically what occurs at an n of 1.27 and what would have to occur at any n above 1.41 where total internal reflection would result whenever internal angles reached 90 degrees. A reflector that worked at 650 nm at normal incidence was made and tested with a laser source at 458nm for reflected components around the predicted input angle of 64 degrees and the minimum P was found near 64 while S was almost all reflected. Other samples were made and tried in a similar fashion and we found that broadband processed thin films fit the lower dispersion curve and thick narrow band films fit the curve corresponding to an n of about 1.4. The dispersion was particularly easy to measure and this final proof also led to some novel flat plate polarizer designs. ===Evidence of a gradient in n=== One of our most used film formulae produces an unexposed thickness of 5 microns, an exposed and processed thickness of 5 microns and a processed but collapsed thickness of 3.5 microns. The mixture is 25% sensitizer, most of which is removed during processing, and these measurements make sense but the diffraction properties are a little difficult to explain. A conformal reflector recorded at 514nm and normal incidence reflects at a center lambda of 580 nm and a bandwidth of 50 nm. It has a weak reflection band extending to about 450 nm and by measuring the dispersion and polarizer angle we know it has an average n of 1.4. If it were uniform and if air replaced the dissolved solids it would have to measure 1.23 times thicker, (over 6 microns),than it actually is to reflect yellow light. It also would not reflect blue light unless some portion of it actually became thinner by about the same amount. This observation leads us to propose that the microstructure actually has a region of net shrinkage with a corresponding high n and low delta n near its glass interface and a region of net expansion of up to 1.5 times and a corresponding low n and very high delta n. From prior work in modeling chirped and graded reflectors we think this is a reasonable conclusion, the only new observation is a probable and reasonable gradient in n. The before and after structures are shown in figure 7. [[File:pg18.gif|center|Figure 7]] '''Bragg plane spacing before and after processing''' '''Figure 7.''' A graphical view of the probable micro structure of a 5 micron thick chirped DCG reflector based on its optical properties. ==IMPLICATIONS OF A LOW N IN DCG DEVICES== The list of problems and advantages of the low n is long and curious. The first advantage we noted was that the original polarization splitters we were working on could now function at 36 or 38 degrees instead of the 53 degrees we originally calculated to be necessary. Fresnel reflections are lower and cross sections are higher at 36 than they are at 53 and everyone is happier. Some other consequences, advantages and design considerations are enumerated below. ===Holographic scanners=== The design of "hologons" in DCG sometimes includes consideration of efficiencies in both P and S polarizations. In general as the angles get larger the combined efficiencies go down, except for a few special angles where delta n * T products can catch S and P both at their peaks if carefully controlled. The designs are usually made with an assumed n of 1.5 to 1.56 and measured efficiencies are usually lower than expected because the final n is really less than 1.4. The full internal angles have become larger than the original exposure angles driving P downward. In designs with slanted fringes, the Bragg condition can rarely be satisfied at the construction input angles after processing. The Bragg error appears to come from a net change in film thickness which tilts the fringes up a little so new compensating exposure angles are calculated to compensate. This correction inadvertently also corrects for the change in n which manifests itself exactly the same as a standing up fringe, closer examination would show that the processed film may have expanded by 10% or less but the correction that was finally necessary was calculated for an apparent expansion of 30%. The excess correction is for the lower value of n. Figure 8 illustrates the effects of expansion alone and then for combined expansion and decreased n in a slanted grating at 633nm. The lower n alters the effective spatial frequency in tilted structures by making the optical path shorter and causing diffraction at a larger full internal angle. The correction for n is essentially an over correction for tilt. In the example the final fringe tilt will be 5 degrees higher than the tilt required in an unchanging n material. Corrections are made and shown for exposure at 488nm. [[File:pg19.gif|center|Figure 8]] '''Figure 8.''' Highly slanted grating with corrections for a shorter wavelength, expanded film and lowered n. ===Holographic zone plates=== An optic with a varying spatial frequency and a varying fringe tilt angle will reconstruct with aberrations if the n changes between construction and reconstruction. An on axis zone plate producing an f/2 cone of light will have an effective increase of spatial frequency in the radial direction so that at the outer edges the diffraction angle could be off as much as .5 mrad. The focal length gets shorter the further off axis the light gets for zone plates requiring collimated inputs and focusing outputs. This is equivalent to a plano-convex lens except that the spherical aberration is in proportion to the net change in n. This implies that if the exposure is made with a plano convex lens instead of a pinhole then the spot size on reconstruction will more closely meet diffraction limited dimensions. Very low f# optics will have problems closer to those in figure 8 and are very difficult to make with precision and correct fringe tilt. If the zone plate is designed without slanted fringes, the equivalent of a double convex lens, then it will not be affected by a change in n. This is in contrast to the refractive equivalent which has considerable spherical aberration. Fringes formed without tilt always diffract at the same external angles no matter what n changes to. Multiple exposure gratings with small tilts and rotations have to be designed with a consideration for a change in n even if no compensation is made for expansion. The change in n usually dominates as a cause for playback errors in any transmission optic that has a tilt in the fringes. ===Multicolor reflection holograms=== A two color reflection hologram can be made with two color exposures and if n and T remain constant then playback will be at the same angles and colors. A good DCG film mixture for two color holograms is 12 microns thick before exposure and 14 to 15 microns thick after exposure and has an initial 6% solid sensitizer concentration. The film expands by a factor of 1.3 causing n to drop to 1.4, resulting in reconstruction at longer wavelengths and different angles. An example of a 2 color design is given to illustrate the relative magnitudes of the changes and the corrections to compensate for them. If we wish to reconstruct at 560nm and 620 nm with a white light incident at 45 degrees, then we must expose at 60 degrees with 458nm and at 51 degrees with 514nm laser light. We should change the input recording angle by 9 degrees between exposures to correct for the change in n and T. In the reflection geometry the bulk of the correction is for the expansion rather than the drop in n. The reflective geometry magnifies fringe tilt errors more than the transmission geometry. The lower n result in an increase in the angular dispersion so that in general DCG refection holograms change color over a wider range with equal tilt than equivalent silver grain reflection holograms which have a higher average n. ===Powered reflectors=== We have produced near on axis reflectors of about f/7 that were constructed and reconstructed at 488 but had enormous aberrations. The focal length was observed to vary by over 2% from center to edge of these reflectors. We always had reasoned that if the reconstruction wavelength were identical to the construction wavelength then the aberrations had to be present in the construction optics if they were observed in the reconstruction. This is clearly not the case for any structure with tilted fringes and a changing n. We had assumed that because the reconstruction was at the same wavelength that no fringes could be distorted because the fringe placement must be identical to the construction geometry. The correct reconstruction color is the result of the film expanding while the index is dropping. The effect of tilted fringes for the reflection case is similar to the transmission case. The effective playback spatial frequency is decreased, the fringes are tilted up a little, the internal angles are the same but the lower n decreases the exit angle giving the optic an increasingly longer focal length as light moves radially outward. Since this is a variable effect the correction can only be iterative and again may be approached by using oppositely aberrated construction waves rather than near perfect spherical waves from pinholes. Construction waves of different curvature may also be used to correct the aberrations in the same fashion that is done to correct for a wavelength shift from construction to reconstruction. ===Reflective polarizers and notch filters=== Notch filters of high density and low n exhibit angular dispersions that span the visible spectrum. One size fits all, we have examples that reflect 650nm at normal incidence and 400 nm at 85 degrees. In fact as mentioned earlier, this dispersion is one of the most convincing proofs of a low average n in these structures. The range of useful polarization separation angles actually runs from about Brewster's angle to 85 degrees in a simple conformal geometry as shown in figure 9. This design is easy to build and easy to make broadband through processing tricks and multiple exposures. Conformal reflectors are the unique case where the diffraction angle for all colors can be the same and the angle for zero reflection of P light is also the same at all reflected wavelengths. A second more complex and untested design is shown in figure 10. It will have some of the properties of a transmission hologram and will not have a very broad bandwidth and will be very difficult to make correctly. The only reason for even doing so is that it may be used close to on axis in a flatter package for illumination of LCD panels and other devices requiring polarized light. [[File:pg21.gif|center|Figure 9]] ''White Light Polarizer'' '''Figure 9.''' A simple to make white light polarizer or polarization separator with proven performance. [[File:polar.gif|center|Polarizer]] ''Polarizer With Tilted Fringes'' '''Figure 10.''' A much more difficult to make polarizer with somewhat unknown and untested properties but near on axis operation. The practical angles and bandwidths are unknown. ==EVALUATION AND CONCLUSIONS== We have illustrated by example and mathematical modelling that DCG always reconstructs with a lower n than it has at the time of exposure. We call this an aerogel effect because it is accomplished with similar procedures to those used in making glass aerogels and exhibits similar properties. Unexposed processed plates of gelatin also expand by as much as 50% and must also exhibit properties of a lower n. Wetted and dried processed plates revert to a higher n and corresponding smaller thickness. A curious side issue is that researchers measuring n with brewster angle methods or index matching methods do not get the low n values that we have observed and demonstrated. These methods measure n at 1 surface only and as we have observed the n may vary widely through the volume. At least one group at Kaiser Optical has published bulk n measurements as low as 1.34 in the past year and others are studying the gradients in n.We have measured the average "effective" bulk n in periodic structures and found that it is important to the design of precision DCG optics of all kinds. Several diffuse object holograms were also tested for a low n and they also exhibit the polarization sensitivity and angular dispersion found in notch filters. We have included these effects in our design software and have found that the model more closely resembles the product, an inclusion of the gradient in the value of n and a curve in the fringes in our modelling would make it even more precise. We will likely pursue these improvements in the future in order to further reduce the surprises we often get. ==REFERENCES== * H. Kogelnik, "Coupled wave theory for thick hologram gratings" Bell Syst Tech J. vol 48, p2909-47 (1969) * R. D. Rallison, "Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug.(1987) * T. A. Shankoff, "Phase holograms in dichromated gelatin" Appl. Opt. 7, p2101-50 (1968) * D. Meyerhofer, "Dichromated Gelatin" Springer-Verlag, Holographic Recording Materials vol 20, chapt.3 p84 (1977) * L. D. Dickson, private communication during 1991. * R. D. Rallison "Survey of properties of volume holographic materials", SPIE vol. 1051, Practical Holography III, p. 68 - LA, CA.(1989) * F. T. S. Yu. "Effect of Emulsion Thickness Variations on Wavefront Reconstruction". bibliog diags Ap Optics 10:1324-8 Je (1971) * R. D. Rallison "Incoherent Multifocus Hololens design and fabrication", SPIE vol. 1183 International Conference on Holography, Optical Recording and Processing of information, Varna, Bulgaria.(1989) * M. Chang and N. George, "Holographic Dielectric Grating; Theory and Practice" bibliog diags Ap Optics 9:713-19 Mr (1970) * R. Kostuk, University of Arizona, Private communications (1991) * J. L. Salter and M. F. Loeffler, "Comparison of dichromated gelatin an dupont HRF-700 photopolymer as media for holographic notch filters".SPIE vol 1555, jul (1991) ''Last modified on 6/10/99'' [[Category:Rallison]] fdf835a400f24851a077f9c6cdf168984e8e5222 0 841 1772 2013-05-11T03:33:43Z Admin 0 wikitext text/x-wiki # "Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)." S.P.I.E. Proceedings, Volume 212, pp.22, 1979 # "Hologram Scanner Design and Fabrication in Dichromated Gelatin (DCG)." S.P.I.E. August, 1982,San Diego # "Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College Holography Workshop and First International Symposium on Display Holography, July 1982. Lake Forest, IL. # "Characteristics of Dichromated Gelatin (DCG) Scanners for Printing Applications" SPIE August, 1984, Vol 498, pp.199. # "Applications of Holographic Optical Elements" Lasers and applications, December 1984, p. 61 # "Pulse Portraits, The Holochrome Process" S.P.I.E., January 1985, Vol 523-01. # "Holographic Optical Elements (HOES) in Dichromated Gelatin (DCG)" S.P.I.E. January 1985, vol 523 p. 40 # "Practical Polymers for Holography", Second International Symposium on Display Holography, Lake Forest College, IL. # "Holographic Scanners for Machine Vision, Printing, and Bar Code Applications." S.P.I.E. January 87, Vol. 747 # "Transmission Holograms for HUDS" SBIR 86.1 Final Report, Wright Paterson AFB, April 1987 # "Cascaded Transmission Holograms for Head-Up Displays" SPIE Vol 883 Holographic Optics, 1988 # "Alternative Volume Recording Media, A Qualitative Comparison" Third International Symposium on Display Holography, Lake Forest College, IL 1988 # "Survey of properties of volume holographic materials", SPIE vol.1051, Practical Holography III, 1989 p.68 LA,CA # "Incoherent Multifocus Hololens design an fabrication", SPIE vol.1183 International Conf. on Holography, Varna, Bulgaria. # "Novel Enhancement of Photopolymers", SPIE vol 1212, Practical Holography IV, 1990, LA, CA. # "Combat Vehicle Stereo HMD", SPIE vol 1456, Helmet Mounted Displays, 1991, San Jose, CA. # "Control of DCG and nonsilver holographic materials" <a name="SPIE1600">SPIE vol 1600</a>, International symposium on Display Holography. # [[Polarization properties of gelatin holograms|"Polarization properties of gelatin holograms"]] SPIE vol 1667, Practical Holography VI, 1992, San Jose, CA. # "Using Thick DCG, 30 to 100 microns" SPIE vol 1914, Practical Holography VII, 1993, San Jose CA. # "Brightness increase in an LCD stereo display" SPIE vol 2176, Practical Holography VIII, 1994, p 241, San Jose CA. # "Holographic Polarization-Separation Elements" Ap. Opt. vol 33, No 23, p. 5378-5385, 10 Aug 1994. # "Wavelength Compensation by Time Reverse Ray Tracing" SPIE vol 2404, p. 217 Diffractive and Holographic Optics and Technology II, San Jose CA, Feb 1995. # [[Wavelength compensation at 1.064µ using hybrid optics|"Wavelength compensation at 1.064 microns using hybrid optics"]], SPIE vol 2689, Diffractive and Holographic Optics Technology III, San Jose CA, Feb 1996 # "Dichromated Polyvinyl alcohol (DC-PVA) wet processed for high index modulation" SPIE vol 3011, Practical Holography XI and Holographic Materials III, San Jose, CA, Feb 1997. # [[Recording Material Selection|"Matching a phase material to an Application"]], Journal of Imaging Science and Technology, vol 41, No 3, 1997 # "Fractured zone plates for spatial separation of frequencies" SPIE vol 3633, Diffractive and Holographic Elements, San Jose, CA, Jan 1999 #"Diffractive Optics replicated in Amorphous IR Glasses" OSA Technical Digest vol 10 Diffractive Optics and Micro-Optics, Jun 8-11, 1998 Kona Surf Hotel, Kailua-Kona, Hawaii # "Large Aperture Scanning Lidar Optics" Final Report for NASA contract NAS5-99192, 20 Nov 1999 # [[History of Dichromates#Serendipity|"Dichromates come from Jello"]], SPIE vol 3956, Practical Holography XIV, San Jose CA, Jan 2000. # [[Media:Zone-SPIE2001.pdf|"Hoe Enhanced 355 nm Multichannel Direct Detection Lidar"]], SPIE vol 4291, Diffractive and Holographic Technologies for Integrated Photonic Systems, San Jose, CA, Jan 2001. # [[Media:FAB_VPHG_spie2002.pdf|Fabrication and testing of large area VPH gratings]], Rallison, Richard D.; Rallison, Robert W.; Dickson, LeRoy D. SPIE vol 4842, Specialized Optical Developments in Astronomy, pp. 10-21 (2003) ''Last modified on 1/14/01'' [[Category:Rallison]] dc70cf0285ce4716aeca58cb64c3326fed22aa17 0 847 1786 2013-05-11T05:16:10Z Admin 0 wikitext text/x-wiki <center><strong> Bio for Richard D. Rallison<br> Box 142, Paradise, Ut 84328<br> (435) 245-4623&nbsp; E-mail rdr@ralcon.com </strong></center> <p> <strong>Education:</strong> </p> <ul> <li>Engineering Studies, Utah State University, 1964-1968 </li> <li>B.S.E.E., University of Utah, 1969-1973 <strong>(Cum Laude).</strong> </li> <li>M.S.E.E. Laser Systems, U.S.C. 1974-75 (not completed) </li> <li><strong>Ph.D. Electro Optical Engineering, Honorary, USU 1995</strong> </li> </ul> <p> <strong>Experience and prior work</strong> </p> <blockquote>Approximately 35 years of professional or technical grade experience. Has been engaged in development work of CO2 Waveguide, Co-Axial Cadmium, Doubled "blue" Yag and Dye lasers at Hughes Aircraft for space communications, countermeasures and underwater communications. Performed ION laser design upgrades at American Laser Corp. and fabricated a novel multiple pass Ruby laser system for Dikrotek. Experienced with diode lasers including fabrication of a small bar code scanner for that coupled a diode laser, grin rod and focusing holographic scanner together. Another device developed and co patented with IBM splits diode laser light into polarized components and replaces a Wollaston prism. </blockquote> <blockquote> An early commercial success for IBM was the development of holographic scanner fabrication methods in 1979, followed by many years of development in Holographic elements, devices and systems and sales of Holographic Optical Element (HOE) fabrication technology to IBM, Pilkington(UK), Holosonics, Seimens, Raven Holographics in England, Portson Inc of Kansas., APA Optics of MN, Northrop corp of CA., Metrologic Instruments of NJ, Process Instruments of SLC, Bell Resources in Australia and Terabeam of Seattle. </blockquote> <blockquote> Work for NASA beginning in 1990 to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have begun. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s. Many spectrographic optical designs, head mounted display designs and some holographic memory designs have been made and brass-boarded. Some have become commercial products. </blockquote> <blockquote> Mr. Rallison has served as a consultant in Diffractive Optics for dozens of companies and has given numerous lectures on holography at the University of Utah, USU and Lake forest College as well as occasional invitations to give paid tutorials in industry. </blockquote> <blockquote>Other work includes the design and fabrication of novel HUD optics for the Air Force on an SBIR<br> grant and an investigation of new holographic recording polymers for the Army NVL on an SBIR contracts. Contracts have been successfully completed for the army at Aberdeen where 5 HMDs were designed fabricated and delivered. Work for VIO in Seattle involved design and fabrication of Stereo Color HMDs or their components. 10 years of work on NASA contracts to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have been attempted. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s such as telecom receivers for free space interconnects developed for another Seattle company named Terabeam, co-founded by RD Rallison.<br> <br> He has fabricated multi lens arrays, gratings, HUDs, notch filters, Fourier filters, scanners, co-phasal multiplexed gratings, spectrophotometer gratings and filters, reflectors, diffusers, depixelators and assorted other HOEs. He owned and operated a company that produced millions of high quality display holograms for commercial use over a 10-year period. He worked as a Video Engineer and Cameraman for a CBS affiliate and prior to that performed work related to weather modification at the Utah Water Research Lab while also producing commercial light shows and devices for entertainment type productions. </blockquote> <p> <strong>Current Organization:</strong> </p> <blockquote>Ralcon Corp. is a vehicle for Mr. Rallison to consult in Optics and develop products. He owns an 8000 square foot facility in Paradise, Utah where laser and Holographic Optics development work has been going on since 1985.The facility is equipped with Argon, Yag, Dye, Nitrogen, HeNe, Ruby and various Diode lasers. Four floating stable tables of various sizes in well insulated rooms provide the basic optical beds and each has its own Argon, HeNe and YAG laser. A machine shop with a variety of glass shaping and polishing machinery compliment the holographic optical fabrication facility. Ralcon Development Lab (RDL) ceased commercial business in June of 2004 at the request the Cache County planning and zoning commission. Commercial customers of RDL have been referred to Wasatch Photonics in Logan UT, which was created in part to continue the work of RDL. Work at RDL is limited to research for NASA GSFC and other government labs.&nbsp;&nbsp; <br> </blockquote> <p> <strong>Professional Affiliations:</strong> </p> <ul> <li>Institute of Electrical and Electronic Engineers </li> <li>Sigma Tau (Honorary Society) </li> <li>Society of Photo Optical and Instrumentation Engineers(SPIE) </li> <li>Optical Society of America (OSA) </li> <li>Aircraft Owners and Pilots association (AOPA) </li> </ul> <p> <strong>Licenses:</strong> </p> <ul> <li>First Class Radio Telephone </li> <li>Private Pilot, SEL, RH, Glider, Hang Glider<br> </li> <li>CDL -class A-air-trailer<br> </li> </ul> <p> <strong>Patents:</strong> </p> <ul> <li>#4,913,990 "method of tuning a volume phase hologram" </li> <li>#5,303,085 and #5,619,377 "Optically corrected helmet mounted display" </li> <li>#4,950,067 "optical system that helps reduce eye strain" </li> <li>#5,291,316 "Information display system having Transparent Holographic Optical Element" </li> <li>#5,602,657 "Hologram system having hologram layers with rotationally offset Bragg planes" </li> <li>#5,519,517 "Method and apparatus for holographically record and reproduce images in a sequential manner" </li> <li>#6,097,543 "Personal Visual Display" </li> <li>#5,991,087 "Non-orthogonal plate in a virtual reality or heads up display" </li> <li>#5,991,085 "Head mounted personal visual display apparatus with image generator and holder" </li> <li>#5,949,583 "Head mounted display with image generator, fold mirror and mirror for transmission to the eye position of the user" </li> <li>#5,945,967 "speckle depixelator" </li> <li>#5,903,396 "Intensified visual display" </li> <li>#5,903,395 "Personal visual display system" </li> <li>#5,864,326 "Depixelated visual display" </li> <li>#5,751,425 "Raman spectroscopy apparatus and a method for continuous chemical analysis of fluid streams" </li> <li>#6,100,975 "Raman spectroscopy apparatus and method using external cavity laser for continuous chemical analysis of sample streams" </li> <li>#5,673,151 "Image correction in virtual reality and heads up displays" </li> <li>#5,642,227 " Optical correction for virtual reality and heads up displays"</li> <li>#6,678,079 “Transceiver for a wireless optical telecommunication system “</li> <li>#6,608,708"System and method for using a holographic optical element in a wireless telecommunication system receiver”<br> </li> <li>#6,369,952 “Head-mounted personal visual display apparatus with image generator and holder”<br> </li> <li>#6,160,666 "Personal visual display system”<br> <br> </li> </ul> <p> <strong>Awards:</strong> </p> <ul> <li>Dept of Defense SBIR Quality Award </li> </ul> <p> <strong>Publications:</strong> Follow [[Publications|this]] link to see our publications list, including links to online versions when available. <br clear="all"> </p> <p></p> <hr> <hr> <h4><em>Last modified on 9/13/2000 [[Category:Rallison]] 980c644ecde2c5a43ad3db53da1fabcfc5bdb08b 0 850 1822 2013-05-11T05:23:42Z Admin 0 Created page with "All of us know something about gelatin and the way it ages and holds up in various environments. It is present in many foods we eat and in leather and furs we wear. It is a fibro…" wikitext text/x-wiki All of us know something about gelatin and the way it ages and holds up in various environments. It is present in many foods we eat and in leather and furs we wear. It is a fibrous felt like substance made up of dozens of amino acids arranged in long polypeptide chains. In leather it has been tanned for strength and lubricated to better stand the flexing. In photographic films it has also been tanned or cross linked to resist abrasion and absorption of water which would cause it to swell and become very soft and perhaps a meal for micro-organisms. In holographic phase only films the degree of hardness plays a key role in determining the clearness of the gel after it has undergone rapid dehydration. We begin to harden it first by cooking it for several hours with water vapor present, then by continued dark reaction with chromate ions, then by exposure to actinic or blue radiation to harden a pattern into it, then through a low ph bath of water and salts such as Kodak fixer with hardener and finally with a post process dry bake out at temperatures up to 120 deg C . This last treatment will increase the density of the film and decrease the legendary affinity it has for water vapor, but it is still far from water proof. ==Hologram formation in gelatin== A DCG hologram is first formed optically by absorbing light and cross linking at the sites where the light is most intense. Then the whole film is swollen in water with the most heavily exposed regions swelling a little less than the unexposed or lightly exposed regions. At this point we have a dimensional magnification of the original fringe pattern where the water has decreased the density of the gel periodically corresponding to the original interference pattern. If it were possible to dry the film at this point without having it change dimensions then there would be a very large difference in the densities of light and dark areas which translates into a large change in permittivity or index of refraction at optical wavelengths. Unfortunately the surface tension of the water causes the structure to collapse to a small index change if left to dry at standard pressure and any temperature. People involved in making aerogels come up against this problem constantly and must resort to the use of pressure chambers, miscible solvents and other tricks to dry out their gels without shrinkage. We have found empirically that a mixture of water and alcohol with a specific gravity of .86 will remove much of the water without collapsing the structure by replacing some of it with alcohol. When the specific gravity is adjusted to about .84 then the structure begins to shrink and the gelatin begins to become more rigid. When we get to .76 to .78 the whole structure is rigid and the manner in which this is done determines the final index modulation of the film and some other properties. Normally the film is soaked with agitation in the .86 bath for a minute or more and then plunged into a much drier bath followed by an even drier and perhaps hotter bath from which it is slowly drawn as a finished piece. Alternatively several more baths may be used to gradually get to the driest possible bath and temperatures should be in the 50 to 70 degree C range for highly modulated broadband films or at room temp or lower for uniformly small modulations. The higher temperatures enable more rapid diffusion of the alcohol into the gel where it can more rapidly dilute, displace and expel the water leaving substantially higher differences between light and dark fringes. ==Heat, Cold and Moisture== Nothing short of laminating the film between two pieces of glass, with a 3 to 6 mm border of gelatin removed from the substrate, will prevent the gel from eventually absorbing enough moisture, when stored at high humidity or near dew point conditions, to cause a total collapse of the holographic fringe pattern. All permanent DCG holograms made since the late sixties have faded to oblivion unless they were stored continually below 90% RH or have been capped with glass. A few thick and dense plastics have also been successful but most coatings and plastic laminates merely act like sponges and then like osmotic pumps carrying water molecules through their surfaces and into the gelatin, which readily accepts it. We always bake our gratings and hoes prior to capping with warm glass, to further insure that the water content trapped in the lamination is small enough to never become a threat to the fragile fringe structure. Trapped moisture that does no harm at room temperature will upon heating become active enough to wet and soften the delicate expanded structure that makes up the diffracting fringes, which will then collapse and join together in a more homogeneous layer, exhibiting only very weak diffraction. The baking is absolutely necessary for stability in extreme environments. We have tested many holographic scanners and outdoor hoes to destruction by baking after capping until the glue holding the parts together decomposes and turns dark. The gelatin and the recorded fringes usually survive up to 230 deg C where they begin to darken and carbonize. Some of this darkening can be attributed to the release of chromium from bonds in the gelatin and its subsequent reduction, along with some chrome salts that were never completely rinsed out during processing. Longer soak times in ever cleaner water baths will remove most of the residual chrome compounds and greatly reduce yellowing by heat and also by UV radiation. The gel does not seem to be affected by low temperatures and the adhesion to glass is good throughout all temperature ranges, provided that the glass was clean and final washed just prior to coating. ==Radiation effects== The effect of high energy radiation on gelatin is also important to anyone intending to put DCG hoes into space or into solar collectors outdoors or into creative lighting designs in buildings where the windows are DCG gratings. Gelatin, like all organic and many inorganic substances will be damaged by photons of more than 4 or 5 electron volts. Eventually all the bonds will be broken if the flux and energy are high enough for long enough. The gel will then be decomposed into loose atoms and molecules incapable of maintaining the original physical form. Fortunately the process takes a very long time to complete, if the gel is protected between two pieces of glass. We have tested holographic scanners sandwiched between two pieces of 1.5 mm thick glass by placing them near a 250 watt low pressure mercury arc lamp for over 24 hours or until the glass itself solarized and became dark near the exposed surface. The gelatin was unchanged in diffractive properties but the glue line and the gel were slightly yellowed which would reduce transmission in the blue region. Less severe tests on display holograms were carried out from 1977 to 1979 where the test pieces were placed out in the open to take on whatever the weather in Salt Lake city and also in New Jersey could dish out. In all cases, for a year or for a month, the glue that we were using then became noticeably yellow but the gelatin and glass remained unchanged within the limits of our ability to measure it optically. Another test was carried out on DCG and three other recording materials that were all prepared in our Paradise lab in 1989 for Northrop electronics division. Several Sample gratings were recorded on thick fused silica substrates and then baked and capped with another silica plate. This time the wave-fronts were measured and photographed before and after the radiation treatments. Neither the efficiency or any other property of the hologram changed from high energy radiation equivalent to several years of direct exposure in space. Somewhere a formal report exists to back up this statement but it did not yield to my searches and the individuals that carried out the work are no longer at Northrop. They did send me some photographs of the wave-fronts and I have those but they cannot tell me what the radiation doses were. In this case the silica could not absorb much of the radiation so it was a truer test of the durability of the gelatin itself. A few of our customers have put our large gratings into green houses as panes of glass and they appear to have survived at least since 1986 or so. Several 16 inch diameter hoes have gone to NASA Goddard where they are used in outdoor LIDAR since about 1991. One early reflection hoe which was not baked out has drifted a little to the blue, nothing that was baked thoroughly before sealing has changed. ==Summary== Our experience with holograms and hoes recorded in DCG since 1974 has been varied and more or less all encompassing with respect to the variety of product and applications possible with this material. We can speak with some authority to the issue of stability and durability in hostile environments. We have made thousands of hoes that have endured 10 or more years of industrial or commercial environments without failing, as long as they were sealed between two pieces of glass at least one half mm thick with at least 3 mm of cleared area near the outer rim of the sandwich. We have also had a lot of failed product that was sent out without that total protection. The O ring type seal formed by the glass to glue to glass bond in the cleared region is absolutely a must for longevity as is the final bake-out before capping. To neglect the O ring will most likely result in a faded recording over time, if ample water vapor is also present. At a minimum the edges of the recording will disappear for several mm into the sandwich. Capillarity pulls the water ever farther into the plates until most or all of the gelatin softens and collapses. Radiation does not seem to be any more hazardous to gelatin than it is to glass and it holds up better than any plastic we have embossed into. Most of the horror stories of disappearing hoes or blue shifting hoes or the loss of some initial efficiency have their origin in less than optimum preparation before capping. We think we know how to do it right and now so do you. ''RDR'' ''Last modified on 2/18/99'' ae87da5794d192bb1f71e9c50c91703ec54ed208 0 830 1702 2013-05-11T05:25:47Z Admin 0 wikitext text/x-wiki <h3>Early researchers (to 1974)</h3> <ul> <li>T. A. Shankoff, "Phase holograms in dichromated gelatin" <em>Appl. Opt.</em> <strong>7:</strong>2101-2105, 1968 </li><li>T A Shankoff and R K Curran "Efficient, high resolution, phase gratings", <em>App Physics Letters</em> 13:pp239-241, 1968 </li><li>L.H. Lin, "Hologram Formation in Hardened Dichromated Gelatin Films." il <em>Ap Optics</em> 8:963-6 My, 1969 </li><li>H. Kogelnik, "Coupled wave theory for thick hologram gratings" <em>Bell Syst Tech J. </em> <strong>48</strong>:2909-2947, 1969 </li><li>R.G. Brandes and others, "Preparation of Dichromated Gelatin Films for Holography." <em>Ap Optics</em> 8:2346-8 N, 1969 </li><li>R.K. Curran and T.A. Shankoff, "Mechanism of Hologram Formation in Dichromated Gelatin." <em>Ap Optics</em> 9:1651-7 Jl, 1970 </li><li>T.P. Sosnowski and H. Kogelnik, "Ultraviolet Hologram Recording in Dichromated Gelatin." <em>Ap Optics</em> 9:2186-7 S, 1970 </li><li>M. Chang and N. George, "Holographic Dielectric Grating; Theory and Practice" <em>Ap Optics</em><strong> 9</strong>:713-719, March 1970 </li><li>L.H. Lin, "Method of Characterizing Hologram-Recording Materials." <em>Opt Soc Am J.</em> 61:203-8 F ,1971 </li><li>Milton Chang, "Dichromated Gelatin of improved optical quality", <em>App Optics</em>, 10 : p2550-2551, Nov 1971 </li><li>D. Meyerhofer, "Spatial Resolution of Relief Holograms in Dichromated Gelatin." <em>App Optics</em> 10:416-21 F, 1971 </li><li>Gary Fillmore, Richard Tynan, "Sensitometric characteristics of hardened dichromated gelatin films" <em>J of Op Soc,</em> 61:pp199-202, 1971 </li><li>K S Pennington, J S Harper, "New photo technology suitable for recording phase holograms and similar information in hardened gelatin", <em>App Phys Lett </em>18: pp80-84, 1971 </li><li>W. S. Colburn, "Holographic Optical Elements", <em>Technical Report, contract F33615-72-C-1156</em>, 1973 </li><li>F. T. S. Yu. "Effect of Emulsion Thickness Variations on Wavefront Reconstruction". <em>App Optics</em><strong> 10</strong>:1324-1328 June 1971 </li><li>D. Meyerhofer, "Phase Holograms in Dichromated Gelatin.". <em>RCA R.</em> 33:110-030 Mr, 1972 </li><li> D. H. Close, A. Graube, "Materials for Holographic Optical Elements", <em>Technical Report AFML-TR-73-267</em>, Oct. 1973. </li><li>A. Graube, "Holograms recorded with red light in Dye sensitized dichromated gelatin", Optics Comm.8:251-253 </li><li>D G McCauley, "Holographic Optical Element for visual display applications", App Optics, 12: 232-241, 1973 </li><li>D.H.Close, A. Graube, "Holographic Lens For Pilot's head up display", <em>Techmical report, contract# N62269-73-C-0388</em>, 1974 </li><li>R D Rallison, "DCG applied with a record player and broadband processed in 2 minutes" <em>Hughes Aircraft</em>, Jan 1974 (never published, just bragged a lot) </li></ul> <h3>Additional selected DCG related publications (to 1996)</h3> <ul> <li>S. K. Case. "Coupled Wave Theory for Multiple Exposed Thick Holographic Gratings".<em> Opt Soc Am J.</em> 65: 724-9 Je, 1975 </li><li>A.Alferness, S.K. Case, "Coupling in Doubly Exposed, Thick Holographic Gratings" <em>Opt Soc Am J.</em>65:730-9 Je 1975 </li><li>R.V. Pole and H.P. Wollenmann, "Holographic Laser Beam Deflector". <em>App Optics</em> 14:976-80 Ap 1975 </li><li>S. K. Case, "Multiple exposure holography in Volume Materials", <em>Doctoral Dissertation</em>, U of Michigan, 1976 </li><li> B.J. Chang, "Post Processing of Developed Dichromated Gelatin Holograms", <em>Optics Communications</em>, <strong>17</strong> (3): 270-271, June 1976. </li><li>T. Kubota, T. Ose, M. Sasake and K. Honda "Hologram Formation with Red Light in Methylene Blue Sensitized Dichromated Gelatin" <em>Applied Optics,</em> <strong>15</strong>(2):556-558, Feb. 1976. </li><li>W. S. Colburn &amp; B. J. Chang "Holographic Combiner for Head-Up Displays", <em>Technical Report AFAL-TR-77-110</em> , Jan 1977 </li><li>H. M. Smith, <em>Holographic Recording Materials,</em> Springer Verlag, 1977 </li><li>A. Graube, "Dye Sensitized dichromated gelatin for holographic optical element fabrication" Photographic Sci and Eng, 22: pp37-41, 1978 </li><li>A. Graube, "Holographic optical element materials research", <em>Technical report, Air Force contract # F44620-76-C-0064,</em> 1978 </li><li>S.K. Case and W.J. Dallas, "Volume Holograms Constructed from Computer Generated Masks." <em>App Opt</em> 17:2537-40 Ag 15, 1978 </li><li>R D Rallison, "Fabrication of a holographic scanning disc" <em>Technical report to IBM</em>, Raleigh NC, 1979 </li><li>R D Rallison, "Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)."<em>SPIE Proceedings</em> 212:22, 1979 </li><li>B.J. Chang and C. D. Leonard, "Dichromated Gelatin for the Fabrication of Holographic Optical Elements", <em>App Opt</em> 18:2407-17 Jl 15, 1979 </li><li>S.P. McGrew, "Color Control in Dichromated Gelatin Reflection Holograms", <em>Proc. SPIE </em><strong> 215</strong>:24-31, 1980. </li><li>B.J. Chang, " Dichromated Gelatin Holograms and Their Applications". <em>Opt Eng</em> 19:642-8 S/O, 1980 </li><li>W.R. Graver et al, "Phase Holograms Formed by Silver Halide Sensitized Gelatin Processing" <em>App Opt</em> 19:1529-36 My 1, 1980 </li><li>S.K. Case et al, "Multi facet Holographic Optical Elements for Wave Front Transformations". <em>App Opt</em> 20:2670-5 Ag 1 1981 </li><li>Sven Sjolinder, "Dichromated Gelatin and the Mechanism of hologram formation", <em>Photo Sci and Eng</em>, 25: pp 112-117, 1981 </li><li>D. A.Winick, "Thick Phase Holograms", Environmental Research institute of Michigan, Level, January 1981 </li><li>L. Solymar &amp; D.J. Cooke , <em>Volume Holography and Volume Gratings</em>, Academic Press, 1981. </li><li>J. Oliva et al, "Diffuse-Object Holograms in Dichromated Gelatin." <em>App Opt </em>21:2891-3 Ag 15, 1982 </li><li>H. Bartelt, S.K. Case, "High-Efficiency Hybrid Computer-Generated Holograms." <em>Appl Opt</em> 21:2886-90 Ag 15,1982 </li><li>R D Rallison, "Hologram Scanner Design and Fabrication in Dichromated Gelatin (DCG)." Proc SPIE, August, 1982 </li><li>R D Rallison, "Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College </li><li>First International Symposium on Display Holography, July 1982 </li><li>L.D. Dickson, "Holography in the IBM 3687 Supermarket Scanner", <em>IBM J. Res &amp; Devel</em> 26:228-34 Mr 1982 </li><li>.J.E. Ludman, "Approximate Bandwidth and Diffraction Efficiency in Thick Holograms." <em>Am J. Physis</em> 50:244-6 Mr.1982 </li><li>Tung H. Jeong, <em>Proceedings of the International Symposium on display holography,</em> Vol I 1983 </li><li>Y.-Z Liang, "Multifocus Dichromated Gelatin Hololens". <em>Appl Opt </em>22:3451-6 N 1 1983 </li><li>A. Fimia, "Noise Reduction in Holographic Images Reconstructed with Blue Light". <em>Appl Opt</em> 22:3318 N. 1, 1983 </li><li>J. Oliva et al, "Dichromated Gelatin Holograms Derived from Agfa 8E75 HD Plates" <em>Appl Opt</em> 23:196-7 Ja 15 1984 </li><li>R D Rallison, "Characteristics of Dichromated Gelatin (DCG) Scanners for Printing Applications"<em>Proc. SPIE</em>. 498: 199, 1984 </li><li>R D Rallison,"Applications of Holographic Optical Elements" Lasers and Applications,pp61-64 December 1984, </li><li>S. Calixto and R.A. Lessard, "Real-Time Holography with Undeveloped Dichromated Gelatin Films" <em>Appl Opt</em> 23:1989-94 Je 15, 1984 </li><li>Ryszard Gajewski "Holographic Technology for Solar Energy Concentration" <em>Technical Report No. 87-1479</em>, 1984. </li><li>C. Solano, Lessard et al, "Red Sensitivity of Dichromated Gelatin Films".<em>Appl Opt</em> 24:1189-92 Ap 15 1985 </li><li>J. C. Newell et al, "Holograms in Dichromated Gelatin: Real-Time Effects" <em>Appl Opt </em>24:4460-6 D 15 1985 </li><li>Jose R. Margarinos &amp;Daniel J Coleman "Holographic Mirrors" <em>Proc. SPIE </em> <strong>523</strong>:203-218, 1985. </li><li>C. Solano and R.A. Lessard, "Phase Gratings Formed by Induced Anisotropy in Dyed Gelatin Plates" <em>Appl Opt</em> 24:1776-9 Je 15 1985 </li><li>Richard D. Rallison, "Holographic Optical Elements (HOES) in Dichromated Gelatin (DCG)", <em>Proc. SPIE</em> <strong> 523</strong>:292-295 (1985). </li><li>S. Calixto et al "Real-Time Optical Image Processing and Polarization Holography with Dyed Gelatin". <em>Appl Opt</em> 24:2941-7 S 15 1985 </li><li>Tung H. Jeong, P<em>roceedings of the International Symposium on display holography</em> Vol II 1986 </li><li>T. Kubota, "Recording of High Quality Color Holograms"<em> Appl Opt</em> 25:4141-5 N 15 1986 </li><li>P. Hariharan, "Silver Halide Sensitized Gelatin Holograms: Mechanism of Hologram Formation." <em>Appl Opt</em> 25:2040-2 Jl 1, 1986 </li><li>R. Changkakoti and S.V. Pappu, "Study on the pH Dependence of Diffraction Efficiency of Phase Holograms in Dye Sensitized Dichromated Gelatin." <em>Appl Opt</em> 25:798-801 Mr 1 1986 </li><li>C. Solano et al Methylene Blue Sensitized Gelatin as a Photosensitive Medium for Conventional and Polarizing Holography" <em>Appl Opt</em> 26:1989-97 My 15 1987 </li><li>Daniel K. Angell, "Improved diffraction efficiency of silver halide (sensitized) gelatin", <em>Appl Opt</em>, 26:4692-4701,1987 </li><li>R D Rallison,"Holographic Scanners for Machine Vision, Printing, and Bar Code Applications." Proc. SPIE 747:pp 1987 </li><li>H K Liu, "Simplified dichromated gelatin hologram recording process", <em>App Optics</em>, 26:372-376, 1987 </li><li>D.J. Jacobs and M. G. Marsland, "Reduction of Sensitizer Concentration Gradients in Dichromated Gelatin Films"<em> J Phys E</em>. 20:899-901 Jl 1987 </li><li>R. D. Rallison, "Materials for Volume Phase Holographic Notch Filters" <em>SBIR #A 86-68 Final Report</em>, U.S. Army CECOM, Ft. Monmouth, N.J. Aug.1987 </li><li>Jon D. Masso "Multilayer Thin Film Simulation of Volume Holograms" <em>Proc. SPIE</em> <strong>883</strong>:68-72, 1988 </li><li>R D Rallison, "Cascaded Transmission Holograms for Head-Up Displays". <em>Proc. SPIE</em> 883: pp 1988 </li><li>N. Capolla and R.A. Lessard, "Processing of Holograms Recorded in Methylene Blue Sensitized Gelatin" <em>Appl Opt</em> 27:3008-12 Jl 15, 1988 </li><li>R. D. Rallison "Incoherent Multifocus Hololens design and fabrication", <em>Proc. SPIE </em><strong>1183</strong>:663-668 1989 </li><li> R. D. Rallison "Survey of properties of volume holographic materials", <em>Proc. SPIE</em> <strong>1051</strong>:68-75 1989 </li><li>James M Tedesco, "Holographic laser -protective filters and eye-wear" Opt Eng 28:p609-615, 1989 </li><li>Y. Amitai et al "Holographic Elements with High Efficiency and Low Aberrations for Helmet Displays", <em>Appl Opt</em> <strong>28</strong>:3405-3416 Aug 15 1989 </li><li>J. L. Salter and M. F. Loeffler, "Comparison of dichromated gelatin and Dupont HRF-700 photopolymer as media for holographic notch filters" <em>Proc. SPIE </em> <strong>1555</strong>:268-278 (July 1991) </li><li>Chris Rich, David Cook, "Lippman volume holographic filters for Rayleigh Line rejection in Raman Spectroscopy", Proc. SPIE 1461:2-7, 1991 </li><li>R. D. Rallison, "Control of DCG and non silver holographic materials" <em>Proc. SPIE </em> <strong>1600</strong>: 26-37 1991. </li><li>R D Rallison,"Polarization properties of gelatin holograms" <em>Proc</em><em>. SPIE</em> 1667:pp 1992. </li><li>R D Rallison, "Using Thick DCG, 30 to 100 microns" Proc. SPIE 1914:pp 1993. </li><li>L D Dickson, R D Rallison et al, "Holographic polarization-separation elements" <em>Appl Opt</em>. 33:5378-5385, 1994 </li><li>R. D. Rallison and S. R. Schicker, "Wavelength compensation by time reverse ray tracing", <em>Proc. SPIE </em><strong>2404</strong>: 217-225 1995 </li><li>Hans Dieter Tholl, "Polarization properties of volume phase gratings", <em>Optical Engineering</em>, <strong>34</strong>(10)2879-2885 Oct 1995 </li><li>Hans I Bjelkhagen, <em>Holographic Recording Materials</em>, SPIE publications, 1996. </li><li>R D Rallison, Steve Arnold, "Wavelength compensation at 1.064 microns using hybrid optics" Proc SPIE 2689, 1996 </li></ul> [[Category:Rallison]] 003a50c2e3a186a7726a6a7ecc4fc13773424154 0 852 1838 2013-05-11T05:37:54Z Admin 0 wikitext text/x-wiki Optical design programs are really fun to use and Time Reverse Ray Tracing is just about the most fun anyone could have with a computer. The object is to model an ideal HOE that works at a wavelength not possible to record at and then go back in time to see how it could have been made, but with a convenient wavelength. Some would call this reverse engineering but that would be a misnomer because the finished product only exists as a math model in your computer. Others would call it designing a null optic, because the object is to feed your ideal optic a completely wrong input wave and null out all the aberrations in the output wave. The null is a little closer except that some solutions require 5 or 6 elements in one leg and a few more in the other leg, and that would be an insanely complex null optic. A few others could probably work out an analytic solution that was close and maybe not even trace it. I typically model the HOE surface, launch a smooth reference wave of 488 nm light through it, look carefully at the mess the HOE makes out of it and then methodically insert real components in the path until the rays converge to a small common point. Obviously, that is the object point where the laser light must have come from to make the HOE that was originally modeled, thus Time Reverse Ray Tracing. The first correction is usually for astigmatism because the original HOE is probably used off axis and a simple off the shelf cylindrical lens will get most of it. Sometimes taking liberties with the Brag condition by moving reference points around will also help reduce the astigmatism and the other aberrations, this can easily be overdone. The next step may be to insert a bent spherical lens and optimize allowing decenters and maybe some limited tilt and maybe some sliding of the cylinder lens. After that the game gets rough quickly, a few more spherical surfaces will gain a little more ground but improvement gets harder and harder to find. The overall object is to get a good focus so that a simple spatial filter can be used to illuminate the optical train you will be building. My design experiences have been very rewarding sometimes and really awful at least once. My worst nightmare was a 1064 nm design that required a bilaterally symmetric binary optic to reduce the aberrations to about 1 wave. The design required help from another designer and the construction took the better part of 6 months just to align all the optics. The computer provided close positioning of the components but the final tweaks required an entire cycle of construction, optical test, computer modeling of the possible error, repositioning of suspected components and construction again. The cycle time was one or two days because the dichromated gelatin optic was 400 mm in diameter. Figure 1 is a scaled phase map of the binary optic we had to fabricate before a carrier was added to move the orders off axis. A metal binary mask was contact copied into several phase media to make it efficient enough to be usable. [[File:timerev2.jpg|center]] <strong><u>Figure 1.</u></strong> Another recent design turned out to be a dream come true. It took about 1 day to complete, requiring only one cylindrical lens, one plano convex lens and a small adjustment of the construction points. Figure 2 shows the 488 nm construction layout for forming a well corrected off axis 100 mm diameter f# 2.3 lens to be used at 532 nm. The reference wave was nearly collimated and the object wave came from a pinhole and passed through only two real off the shelf lenses. It was straight forward to align the optics and easy to verify that the design worked. The fringe tilt error introduced during master construction was corrected in a simple contact copy made at a compensating angle. Rays were traced to just 1 wave of error and measured spots at 532 nm were about 50 microns, about the limit for the glass used. All the design work was done in ZEMAX-EE but could have been done as well in SE. [[File:timerev1.gif|center]] <strong><u>Figure 2.</u></strong> Time Reverse Tracing is limited at present by the inability to insert optics into the construction path of standard HOE surfaces in any current optical design program. When that becomes possible, many more ideal HOEs may be modeled and reverse traced at convenient wavelengths. A General Holographic Surface has been proposed for inclusion in a future version of ZEMAX and KDP optics. No telling when it will become worthwhile. ===Primary References:=== * "Wavelength Compensation by Time Reverse Ray Tracing" SPIE vol 2404, p. 217 Diffractive and Holographic Optics and Technology II, San Jose CA, Feb 1995. * [[Wavelength compensation at 1.064µ using hybrid optics|Wavelength compensation at 1.064 microns using hybrid optics]], SPIE vol 2689, Diffractive and Holographic Optics Technology III, San Jose CA, Feb 1996. ===Other References:=== * ''Wavelength Scaling Holographic Elements.'' M. Malin and H.E. Morrow. Opt Eng 20:756- 8 S/O '81 also in SPIE vol 240 p 2, 1980, San Diego * ''Analytic Design of Optimum Holographic Optical Elements.'' J.N. Cederquist and J.R. Fienup. bibl diags J Opt Soc Am A 4:699-705 Ap '87 * ''Analytic Optimization for Holographic Optical Elements.'' E. Hasman and A.A. Friesem. bibl diag J. Opt Soc Am A 6:62-72 Ja '89 * ''Design of Holographic Optical Elements by Using Recursive Techniques.'' Y. Amitai and A.A. Friesem. bibl il diags J. Opt Soc Am A 5:702-12 My '88 * ''Computer-Based Analysis of Hologram Imagery and Aberrations.'' J.N. Latta. bibliog diags Ap Optics 10:599-618 Mr '71 * ''Holographic Elements with High Efficiency and Low Aberrations for Helmet Displays.'' Y. Amitai and others. bibl il diags Appl Opt 28:3405-16 Ag 15 '89 * ''Holographic Zone Plates for f'0 and Collimating Lenses.'' Y. Ono and N. Nishida. diags Appl Opt 25:794-7 Mr. 1 '86 * ''Iterative Method Applied to Image Reconstruction and to Computer-Generated Holograms.'' J.R. Fienup. bibl il diags Opt Eng 19:297-305 My '80 * ''Design Techniques for Forming 488-nm Holographic lenses with Reconstruction at 633 nm.'' M.R. Latta and R.V. Pole. bibl il diags App Opt 18:2418-21 Jl 15'79 * ''Compensation of Wavelength-Shift Aberrations in an off-axis Holographic Zone Plate.'' E. Wihardjo and others. bibl il diags Opt Eng 25:871-4 Jl '86 * ''Cindrich, ed. Holographic Optics: Design &amp; Applications.'' 1988. 50.00 (ISBN 0-89252- 918-0, 833). SPIE * ''Computer Originated Aspheric Holographic Optical Elements.'' R.C. Fairchild and J.R. Fienup. bibl il diags Opt Eng 21:133-40 Ja/F '82 * ''Recursive design of a holographic focusing grating coupler.'' Y. Amatai, I. A. Erteza, J. W. Goodman. Ap Opt vol 30, no 27, p 3886 Sep 91 * ''Using a Conventional Optical Design Program to Design Holographic Optical Elements.'' C.W. Chen. bibl diags Opt Eng 19:649-53 S/O '80 * ''Describing Holographic Optical Elements as Lenses.'' W.C. Sweatt. bibl diags Opt Soc Am J. 67:803-8 Je'77 * ''Compensation of Aberrations Due to a Wavelength Shift in Holography.'' J.M. Moran. il diags App Optics 10:1909-13 Ag '71 * ''Computer-Based Analysis of Holography Using Ray Tracing J.N.'' Latta. bibliog diags App Optics 10:2698-710 D '71 ''Last modified on 1/11/98'' [[Category:Rallison]] 568661a98b1c9e7c2b96e061be6ce7503924e29f 0 853 1846 2013-05-11T14:39:33Z Admin 0 wikitext text/x-wiki {| border=1 |- | colspan="3" | '''Key''' |- | a = input angle in air || b = output angle in air || a_n = input angle in medium |- | b_n = output angle in medium || f₀ = spatial frequency = 1/d || λ = wavelength |- | n = index of refraction || Δn = index modulation || D.E. = diffraction efficiency |- | φ = The half angle || d = grating period || T = thickness of medium |- | ρ = regime factor || Q = quality factor || B = fringe tilt angle |- | 0, +1, -1, +2, -2 = diffraction orders possible || f = focal length || f# = f number |} {| border=1 |- | '''Grating equation, transmission''' |- | f₀λ = sin a + sin b |- | D.E. <u>~</u> sin² [Δn T / (λ cos φ)] < 99.9% |} {| |- | colspan=2 | Plane grating, slanted fringes, +3 order is TIR, Δn is asymmetric |- | [[File:fig1.gif]] | * <math>\Delta \lambda \simeq \frac{\lambda d}{T \tan{\phi}} \simeq \frac{\lambda \pi \Delta n}{8 n} \simeq \lambda \arcsin{\left(\frac{1-Q}{1+Q}\right)}</math> * <math>a_n = \arcsin{\left(\frac{\sin{a}}{n}\right)}</math> * <math>b_n = \arcsin{\left(\frac{\sin{b}}{n}\right)}</math> * <math>B = \frac{b_n - a_n}{2}</math> * <math>\text{Bragg ratio} \beta = \frac{T \lambda}{d^2}</math> * <math>\phi \simeq \arcsin{n \sin{\left(\frac{a_n + b_n}{2}\right)}}</math> * <math>\text{Number of superimposed recordings} \simeq \frac{n T}{\lambda}</math> * <math>\text{Resolving Power} \frac{\lambda}{\Delta \lambda} \simeq \text{number of fringes}</math> |} {| border=1 |- | '''Grating equation, reflection''' |- | <math>\displaystyle f_0 \lambda = n (\cos{a} + \cos{b})</math> |- | <math>D.E. \simeq \tanh^2{\left(\Delta n T / \left(\lambda \cos{\phi}\right)\right)} < 99.9998%</math> |} Uniform tilted reflector, also has weak transmission grating at surface. {| |- | [[File:fig3.gif]] | * <math>\Delta \lambda \simeq \frac{\lambda d}{T}</math> * <math>\Delta \theta \simeq \frac{d}{T}</math> * <math>\displaystyle 0 < \Delta n < 0.27</math> * <math>\displaystyle 3 u < T < 50 u</math> * <math>\rho = Q \frac{\lambda^2}{d^2 n \Delta n} \simeq \frac{2 \pi \lambda T}{d^2 n} \simeq \frac{2 T}{d^2}</math> * <math>\frac{1}{\rho^2} \propto \text{power lost to higher orders}</math> |} ''Last modified on 9/29/97'' [[Category:Rallison]] b92b653db2c77043def83db1ad6f3a2ea957401b 0 854 1852 2013-05-11T15:24:09Z Admin 0 wikitext text/x-wiki Richard D. Rallison<br> Ralcon Development Lab, Box 142, Paradise UT, 84328<br> ph (435) 245 4623, fax 6672, e/mail rdr@ralcon.com<br> Steven M. Arnold<br> Diffraction International, 11345 Hwy 7, #421, Minneapolis MN, 55305<br> ph (612) 945 9912, fax (612) 945 9912<br> ==ABSTRACT== The wavelength scaling of an f# 2.5 off axis HOE from 488 nm to 1064 nm has been done. We canceled large induced astigmatism, and other higher order aberrations using a combination of 1 curved reflector, 1 cylindrical lens and one Null CGH bonded to the cylindrical lens. The task was made more difficult by a requirement to fill a 404 mm round aperture and make it focus to a 53 micron diameter spot at the 1/e clip level. The design procedure, the construction sequence and the measured results are presented as a work in progress. ==INTRODUCTION== Our primary objective is to design and construct a 45 deg off axis f#2.5 [http://lazer.gsfc.nasa.gov/ Lidar] scanning optic for operation at 1.064µ. The focal length was selected at 1016 mm with the focus centered and normal to a 404 mm diameter glass sandwich, and the input was designated to enter from 45 degrees off axis so that conical scans of the sky could be made. We had previously tried to obtain a 500 micron spot with an f# 4 design at 670 nm and had succeeded nominally using only a tilted 60 mm fl parabolic mirror and two positive cylindrical lenses¹ to correct the astigmatism and some of the coma like aberration. We also made a design that predicted better performance using a large, tilted and decentered medium power positive meniscus lens, a tilted negative cylinder and a 446 mm D by 1994 mm fl telescope mirror. The design looked good enough to try and we converted to 1.064µ, reoptimized and made a prototype. The spot became nominally smaller, about 400µ but not the 250µ that the design predicted, probably because alignment errors were accumulating. We then added two more weak meniscus lenses on axis to reduce spherical and replaced the large tilted medium power meniscus with a smaller but much stronger positive meniscus to further reduce coma. The predicted spot was to be 200µ plus whatever the random phase error in the glass substrate might add. The computer model was not faithfully translated to actual optics and we had considerable residual astigmatism and other aberrations left over. We measured narrow areas in the lines down to 200 microns and decided the set up had to be simpler and the design had to reduce the aberrations to a few waves, not the hundred or more waves we had been getting. ==DESIGN CHANGES== ===Conventional spherical optics.=== The last two conventional optics designs I actually tried and tested were nightmares 1064B and 1064F, the layouts are shown in figure 1 with some thru focus diagrams. The apertures of the optics prevented making a full aperture HOE. Figure 2. is the test layout at 1.064µ which also shows the way the HOE is supposed to work and some of the best measured "spots" are shown. {| |- | [[File:fig1-1.jpg]] [[File:fig1-2.jpg]] |- | Figure 1. Construction layouts using only available conventional optics and traced spots of about 150µ. |} {| |- | [[File:fig2-1.jpg]] [[File:fig2-2.gif]] |- | Figure 2. The test set up used to measure the reconstructed point at 1.064µ and some measured spots. The space between dark parallel lines is 63 microns. Astigmatism dominates. |} These designs began to look like dead ends, as the number of elements increased, the number of possible configurations ballooned and optimization became far from obvious. It was clear that a custom made surface was the only practical solution, the two choices were a potato chip chunk of glass or a binary phase HOE. We had a lot more experience with phase HOEs so I asked Steve Arnold for help. ===Hybrid refractive / diffractive surfaces=== Steve suggested we zero out the phase error with one of his CGH nulls² placed on the flat side of a cylindrical lens, creating a hybrid optic. If the CGH were made into a binary phase structure we could have as much as 40% in the desired order. I imagine that the alternative would have been to shape a surface into something like a Pringles potato chip and attach it to the lens. Steve took my zemax generated design and plugged in the appropriate numbers to his super oslo program and went to work. There was a bit of luck going for us. The telescope mirror could be moved just a little and be made to form a line focus a comfortable distance from the cylinder, enabling us to mask out unwanted orders from the binary optic. He also found that the exit light from the lens was about 35 mm in diameter and fairly uniform, the size and uniformity was favorable for fabrication of the binary CGH and for playing it back through the system at 488 nm. The number of waves of correction was also manageable at about 160. The optimization in oslo, subsequent chrome mask generation³ and phase element fabrication went smoothly, the final assembly traced out to yield about 1 wave of higher order aberration. I also took a crack at designing the CGH in zemax but I was only able to optimize to about 4 waves (20µ spots), obviously I still have something to learn. I was much more successful at converting a chrome mask version of his oslo design into a high efficiency volume phase HOE. Simple contact copies into Dupont photopolymer⁴ yielded 30% in the 1st order, copies into UV glues diffracted up to 14%, dichromated gelatin in 25µ thicknesses grabbed 26% and unbleached silver grain films diffracted about 4% to 6%. The original chrome mask was not measured. The dichromate copies had the best optical properties. The phase only CGH from Steve, made on photoresist, measured about 18% efficiency at 488 nm and was clean and scratch free until I started using it. At this point I have done so much damage to it I will probably have to get a new cylindrical lens and bond a DCG copy of the chrome mask to it and begin again, in order to get the best possible recording. The original assembly mated fused silica to a flint glass lens, which gives rise to an interference pattern in the object beam that could be reduced by recording the DCG copy on a flint substrate, and damage in use can be minimized by capping the DCG with a thin AR coated cap of flat 7059 glass. A photo of the Hybrid optic is shown in figure 3 below, alongside of a scaled image of the pattern minus the carrier we added to it. There are 20 waves of error per fringe. {| |- | [[File:fig3-1.jpg]] [[File:fig3-2.jpg]] |- | Figure 3. The hybrid optic from Diffraction International and the CGH pattern without carrier. |} ===Modeling in zemax and in oslo=== I made an attempt to model the oslo diffractive design in zemax using the following conversion formula but I could not make it work properly. Those who are familiar with oslo or zemax will recognize some of the terms. The As are the possible 65 polynomial coefficients optimized in oslo, the Bs are the corresponding coefficients in the zemax binary 1 surface. The j+k is the sum of the powers of x and y and the quantity in brackets is a phase in waves, unique to oslo or at least not chosen in zemax. <center> <math>B_i = \rho^{(j+k)}\left[\frac{2 \pi M}{\lambda_r}\right] A_i, \text{ where } \rho = 100 \text{ if mm are chosen lens units.}]</math> </center> We need the conversion so that either model can be rearranged to accommodate another exposure geometry for this work in progress. At least 5 other designs have to be worked out and fabricated before we are done with this project. At least one of them could use the same CGH. Another improvement to the model would be an accurate representation of the B270 sheet glass substrates we are working on. The sheets appear to be consistently flat within a few waves in one direction and rippled a few more waves in the other direction, one side is usually flatter than the other, which will not matter since we are bonding two plates together with flat sides turned outward and rippled sides index matched together. The figure below shows the final recording geometry using the Hybrid optic with the diffractive part bonded to the flat backside of the refractive part. All parts were initially positioned within 1 or 2 mm of the optimized position and all angles were within about 3 mrad. Sadly, that was not close enough to produce the desired results and many adjustments have been made during trial fabrications. A three axis mount was used to position the hybrid but the parabolic mirror gave us most of the alignment trouble. {| |- | [[File:fig4.jpg]] |- | Figure 4. The final layout design using the Hybrid optic. |} ==CONSTRUCTION OF HOE== The coated plates are our own spun on dichromated gelatin⁵ (DCG) with 30 percent dichromate in a 7 - 8 micron layer of Grayslake gelatin. We age it at room temp for 2 or 3 days prior to exposure so that it will harden and reconstruct with maximum clarity. Most plates are clean and uniform and otherwise consistent and reproducible. The exposures so far were made with about 600 mwatt of 488 nm light from an argon laser and the required energy is 10 mJ/cm*cm for masters and 40 mJ/cm*cm for infrared copies. Processing is in standard IPA and water preceded by a 2 minute soak in Kodak fixer. The plates are typically cycled through each bath in 30 seconds with continuous agitation and are reprocessed as needed to get peak diffraction efficiency at 1.064µ or for masters adjusted to 50% @ 488 nm. An entirely new processing station was constructed for this project. About 50 gallons of IPA is now heated to 55 deg C with circulating hot water. The water is pumped through a remote gas water heater and stainless steel tubing looped in the bottom of each of three processing tanks, enabling economical and safe operation. Figure 5 below shows the process station and optics with mounts used during exposure. In this work we exposed 406 mm square (16 in) B270 plates with exposure times of from 4 to 16 minutes. The chance that something will warp or bend or that the laser will drift during that time is about 10:1. An electronic fringe locker was used to be certain that at least one portion of the HOE would always turn out perfectly. When all due precautions had been taken and extended settling times provided for, the results were good. All of the goals for this project have not yet been met. We will yet have to produce a contact copy from a master using apodizing techniques to get a uniform response over the entire aperture. The contact copies can also be made to meet the Bragg condition more uniformly because the angle the copy light travels in has only a small effect on the diffraction pattern but a large effect on the tilt of the Bragg planes. The best possible copy beam at 488 nm will be an astigmatic wave, produced by placing an appropriate cylindrical lens some distance in front of a pinhole. This work has yet to be done. {| |- | [[File:fig5-1.jpg]] || [[File:fig5-2.jpg]] |- | 3 hot IPA and 2 cool Water and 1 Fix tank || Optics used to form Object wave |- | colspan=2 | Figure 5. The 406 mm (16 inch) processing station and the hybrid optic with associated mounted optics. |} ==EXPERIMENTAL RESULTS== As of this writing we have achieved a slightly astigmatic spot that measures only 60µ in the direction of diffraction at the 1/e clip level and is about 70µ at the other best focus, a mm in front of the best spot. Measurements were made with a Beamscan rotating slit from Photon inc. Spot profiles were also viewed on a screen that attached to a Rhonchi rule with 63µ open spaces. The first two spots shown below in figure 6 belong to plate # 8 and meet our criteria, except for that tiny mm of astigmatism. These spots were found in a HOE that was misaligned somewhat in the Z direction, which made me suspect that one of the powered components was not made as modeled. We had modeled the mirror assuming it had a 1994 mm (78.5 inch) focal length and it is really 1999 mm (78.7 inches). I have another mirror that is 1996 mm (78.6 inch) fl and have since substituted it and moved it back slightly to account for the change. It was then that I discovered just how sensitive the system was to a tiny tilt error around the Y axis. Spots 3 and 4 from plate #13 were the result of less than .05 degree error in the tilt of the telescope mirror. Spots 5 and 6 from plate #15 are the result of translating the hybrid optic in the x direction 2 mm and tilting the mirror .5 degrees about y. Moving the hybrid optic 2 mm along the Z axis only doubles the spot size. We are going for as near to zero aberrations as we can practically get and are continuing to fine tune the set up to eliminate as many measurable flaws as possible. Unfortunately the current set up is not yet producing spots as small as the previous set up and fine tuning with big plates is extremely time consuming, nevertheless we now expect to get 60 micron spots in a finished product.</blockquote> {| |- | [[File:fig6-1.jpg]] || (best place to date) || [[File:fig6-2.jpg]] |- | #1, far focus 1016 mm || plate #8 || #2, near focus 1015 mm |- | [[File:fig6-3.jpg]] || (close second best) || [[File:fig6-4.jpg]] |- | #3, far focus 1017 mm || plate #13 || #4, near focus 1013 mm |- | [[File:fig6-5.jpg]] || (result of changing mirror) || [[File:fig6-6.jpg]] |- | #5, far focus 1016 mm || plate #15 || #6, near focus 1008 |- | Figure 6. Three sets of measured through focus spots, from 3 recent plates. Plate #8 had only 1 mm between spots, # 13 had 4 mm between and #15 had 8 mm. The space between dark bands is 63µ. |} ==ACKNOWLEDGEMENTS== We wish to thank Geary Schwemmer of NASA GSFC for sponsoring this LIDAR optics project. We also acknowledge the help of prof Thomas Wilkerson of U of MD, now at USU and of prof Stephen Bialkowski of USU for helping with analytical methods and pattern generation. The help with oslo / zemax conversion was provided by Ken Moore, author of zemax. ==REFERENCES== # R. D. Rallison and S. R. Schicker, "Wavelength compensation by time reverse ray tracing", SPIE vol 2404, p 217, 1995, San Jose, CA. # Steven M. Arnold, L. Curt Maxey, J. E. Rogers and R. C. Yoder, "Figure metrology of deep general aspherics using a conventional interferometer with a CGH null", SPIE vol 2536, July 1995. # Steven M. Arnold, "Desktop computer encoding of electron-beam written holograms" SPIE vol 884, p23, 1988. # Felix P. Shvartsman and Moshe Oren, "Photo-lithographic imaging of computer generated holographic optical elements" SPIE vol 1555, p 71, 1991. # R. D. Rallison, "Control of DCG and non silver holographic materials" SPIE vol 1600, p 26, 1991. Lake forest college, Il. ==Deleted from the original== ===Secondary HOE=== Another way to ruggedize the system and get more light in the diffracted order is to record the diffracted wavefront with a 30 degree off axis point source reference in 8 of DCG. A convenient plane to record this secondary HOE is found about 200 mm from the mask plane where the pattern is uniform and fits nicely on a 200 mm square plate. The secondary HOE replaces the Hybrid HOE in all subsequent recordings and makes exposures shorter and more likely to succeed. Alignment errors could be worse. This is an abstract submitted for the SPIE conference on Diffractive and Holographic Optics Technology III. Jan 27- Feb 2, 1996 in San Jose, CA. Copies to Steve Benton 6172538823and SPIE 2066471445 and Ivan Cindrich 3139945824 and John Trout 3026959631 Ralcon fax # 801 245 6672 Diffraction Int fax 612 945 9912 WAVELENGTH COMPENSATION AT 1.064 MICRONS USING HYBRID OPTICS Richard D. Rallison Ralcon Development Lab, Paradise UT Steven M. Arnold Diffraction International, Minneapolis MN Holographic Optics designed for use in the near IR region cannot usually be made with near IR lasers. Common recording media is naturally more sensitive to higher energy visible (blue) wavelengths. The large wavelength shift produces large aberrations. We previously made off axis focusing HOEs for 1.064 microns with blue light at 488 nm with refractive and reflective optics to reduce aberrations. We recently had success nearly nulling out those aberrations by adding a general diffractive surface to one of the refractive optics. We have reduced the errors in the IR wavefronts to a few waves over a 404 mm aperture using only off the shelf optics and a custom CGH. The method results in complete construction geometries being generated ready for implementation on a table. The general method used is time reverse ray tracing of the refracted and diffracted construction wavefronts. A 2 degree carrier is added to the phase map to separate and block unwanted diffraction orders. A binary phase HOE is then generated to diffract 35% or more of the 488 nm light into the construction path. Super OSLO and Zemax optical design programs are used to design the construction optics. ''Last modified on 6/1/99'' [[Category:Rallison]] eda29625217ad9735fff1b893c6a269564cb8769 0 855 1854 2013-05-11T15:34:17Z Admin 0 Created page with "===Update=== Ralcon has developed a&nbsp; line of gratings that acheive near 100% diffraction efficiency at high angles, typically 46 to 48 degree half angles. These are believe…" wikitext text/x-wiki ===Update=== Ralcon has developed a&nbsp; line of gratings that acheive near 100% diffraction efficiency at high angles, typically 46 to 48 degree half angles. These are believed to be unique because the dispersion is very high and both polarizations are diffracted equally and fall off on each side of center in the same direction. We call this new grating the Dickson grating in honor of its inventor LeRoy Dickson, a retired IBM research scientist. Manufacturing is handeled by http://wasatchphotonics.com]. A white paper on the subject of this grating and DWDM can be found in pdf format and downloaded [[Media:DWDM-Dickson_grating_white_paper.pdf|here]]. ==This is What's happening (or happened through Sept 2005)== Volume Phase Gratings (VPG) for spectrographic applications have become an important part of WPs&nbsp; business..&nbsp; WP has listed the specific gratings that have been made by frequency, wavelength, bandwidth or size and many more are for OEM&nbsp; customers. Go to their website for more detailed technical information and pricing.<br> ===General VPH information=== Most of our production gratings are between 1 inch and 8 inches on a side or diameter and work between 350 nm and 2400 nm. Most are on low iron or borosilicate sheet glass and a few are on fused silica. The largest ones are on Pilkington float glass. The gelatin layer is typically 5 to 20 microns and the spatial frequencies run from 90 l/mm to about 2000 l/mm, but can be much higher. Bandwidths are typically several hundred&nbsp; nm and are free of anomalies. The Bragg sensitivity or Blaze angle is adjustable with small tilts and the modulation can be peaked for either linear polarization or equal for both polarizations at a particular wavelength. These are very versatile gratings and come with durable AR coatings if required. The peak efficiencies are in the 90% range and the roll-off is smooth on both sides and slightly asymmetric, favoring longer wavelengths. Fractional wave performance is easily achieved with symmetrical designs(same angle in and out). Typically we expose the gratings in DCG with well collimated light on glass that is only flat to a few fringes per inch. Then if fractional wave performance is needed, the gratings can be capped with a flatter cover-glass on one or both sides. Most of the phase shifts due to uneven surfaces are index matched out in the lamination process. The final diffracted wavefront will then be well corrected and the covers also carry the AR coatings. Alternatively the plate glass can be polished flat and coated after the grating has been exposed, tuned and capped. Less frequently we coat the gelatin directly on an AR coated flat and cap with the same. Substrate sizes less than 4 inches are not good candidates for this method and we always require several extra flats so we can do a "batch" and select the best. We have a few mathcad templates for gratings design and performance analysis that can be had for the asking. We now have a Zygo phase shifting interferometer and can test diffracted wavefronts to 1/100th wave if needed. Ralcon is now in partneship with a new startup grating manufacturer called Wasatch Photonics headquartered in Logan UT. Visit http://wasatchphotonics.com for details. ''Last modified on 9/11/05'' [[Category:Rallison]] df183ec0b6e4fa6dc85b5a75c2350db767def6b4 0 856 1860 2013-05-11T16:18:23Z Admin 0 Created page with "==Zone Plate Equations== [[File:15zones.gif|right]] <strong>Variables</strong> * f = focal length * λ = wavelength * ρ_r = phase variation * r_m = radius o…" wikitext text/x-wiki ==Zone Plate Equations== [[File:15zones.gif|right]] <strong>Variables</strong> * f = focal length * λ = wavelength * ρ_r = phase variation * r_m = radius of m<sup>th</sub> zone * m = zone number * 1 &le; N &le; ∞ <strong>Definitions</strong> * GZP = Geometric Zone Plate, paraxial, f# &gt; 10 * IZP = Interferometric Zone Plate, f# &lt; 10 * GHZP = Generalized Holographic Zone Plate <strong>Equations</strong> * For GZP: <math>r_m = \sqrt{2 m \lambda f}, \, \phi_r = \pi r^2 / (\lambda f)</math> * For IZP: <math>r_m = \sqrt{2 m \lambda f + {(m \lambda)}^2}</math> * For GHZP: <math>r_m = \sqrt{2 m \lambda f + {(m \lambda / N)}^2}</math> ==Properties of Zone Plates== * <math>\text{Minimum zone width } \simeq 2\lambda f\sharp \simeq \text{ minimum spot size}</math> * <math>\text{Depth of focus } \simeq 2 \lambda {f\sharp}^2</math> * <math>f = \frac{f_m^2}{2 m \lambda}, \, f\sharp = \frac{1}{2 N A} = \frac{f}{D i a}</math> * <math>\text{Chromatic aberration } \Delta \lambda \simeq \lambda / m</math> (m = number of zones illuminated) * Hybrid condition (f zone)/(f lens) = (n-1)/λ (dispers const.)) * Hybrid Achromats typically use GZP pattern and less than 300 zones ''Last modified on 9/22/97'' [[Category:Rallison]] c1f676adf620238c490cd4a78876130ca437a4e5 0 845 1780 2013-05-11T16:44:52Z Admin 0 moved [[Recording Material Selectoin]] to [[Recording Material Selection]] wikitext text/x-wiki =Phase materials for HOE applications= Richard D. Rallison<br>Ralcon Development Lab, Box 142, Paradise UT, 84328<br>ph (435) 245 4623, fax 6672, e/mail rdr@ralcon.com The choice of a phase recording material strongly affects the utility of the final recording. For display holograms properties like brightness, contrast, color range and color saturation might dominate and the choices are part art and part science. For HOEs, the extended range of properties that may require manipulation and the choices of materials to obtain each property in the required quantity, makes a working knowledge of what can be done extremely useful. This paper presents the fundamental properties of phase recordings and the fundamental properties of many phase materials so that a choice that will get a person from plan to product can be more readily made. Recipes are not given but references to recipes are and modifications or procedures that can modify a well known material may be described. The object of this paper is to make the reader aware of both the strong functions of these materials and the weak or subtle properties so that a design may be reviewed for feasibility a little more thoroughly and hopefully the route to a functioning product will be shorter and less costly. ==Introduction== The phase recordings we will consider are the simple transmissive sinusoidal volume plane grating, the powered or focusing volume grating, the general reflective volume grating with the two special cases of a conformal reflection recording and a strong spherical wave recording and finally the large class of surface phase gratings so popular because of the supposed ease of fabrication. We first identify as many of the properties of these phase structures as we can, then discuss the variations and mix of these properties that may be required in a well functioning final copy. At this point we define the minimum performance required of the end product and then list some popular media to choose from. In order to make a good first choice we need to know the intrinsic properties of these materials and their limitations, strong and weak points, cost, availability and perhaps what would be termed their "nuisance factor". This last factor is the reason I end up with plenty of work to keep me busy. Very often the art gets in the way of the science, the recipe has too many variables, the learning curve is a little too long and the literature a little too short and probably ambiguous and contradictory. We will use unscaled illustrations as much as possible and keep things as simple as possible, steering clear of any exhaustive validations of claims made for different materials or the chemistry involved. The reference material can be used to satisfy these other needs. Only simple algebraic equations or approximations are used without formal justification. ==Basic phase diffracting structures== Each of the figures 1 through 5 represent a common spatial phase modulator. The simple plane grating covers a wide terrain, wide enough to include transmissive display holograms made in bleached silver grain films which can be thought of as being made up of very many superposed plane gratings or as many tiny spatially multiplexed gratings. The reflective grating covers just about everything else that could be made but we have to consider the subtleties of various configurations and some special cases. Surface phase gratings are not just thin volume gratings, they have become a large class of optics themselves, referred to as diffractive optics (DOEs) and they enjoy considerable popularity at the present time. Some materials in common use today can be used to fabricate all of these diffraction structures, but none will cover all possible constructions within every class. Within the description of the properties of the HOE that is to be fabricated is the description of the material that will have to exist to make it. In most cases the material does exist and may be available in some form, but not always on the right substrate and in the right thickness. In real materials the direction that light transits through the HOE makes a difference, sometimes a large difference, the efficiency of a grating can actually be greater in one direction because of gradients in the modulation and holographic mirrors often reflect different spectra on each side with different intensities. ===Basic transmissive volume holographic gratings.=== Fig 1. Depicts an edge view of a section of a plane grating of thickness (T) of fringe spacing (d), at the surface and of fringe tilt or Brag tilt (B). The fringes themselves are regions of hi and low index (n) with the differences referred to as (Δn). The product of ΔnT is the total modulation of the grating but the diffracted light in each order also depends on angles a and b and wavelength (λ) which together define d. The change in index is usually not uniform through the film. It is common wisdom that the thicker the grating, the narrower is the angular bandwidth and the better is the suppression of higher orders, if they can exist. The other half of that assumption is that the value of Δn is small enough to make the product of ΔnT just large enough to diffract all of the light. If in fact the product is 2 or 3 times that high, the grating will behave as a 3 or 4 times thinner grating. Materials that require wet processing almost always have a gradient in index that can be very high, further reducing the effective thickness of the grating. Even real time recording materials, including photorefractive crystals have a gradient in index from absorption and behave as if they were much thinner than they are. The power lost to higher orders is proportional to Δn² so if modulation is excessive then not only is a thick grating rendered thin but it may diffract most of the incident power into useless orders. Another gotcha in dealing with thick gratings is the wandering Brag tilt B. Whenever wet processing is used there is a high probability that the original tilt made during exposure will play back at some other angle. In very thick gratings this error can exceed the angular bandwidth of the grating and render a non uniform grating that is useless. Thick gratings made in low shrinkage photopolymers and photocrosslinkers that require no processing seem to work well enough. If the intended use of the grating requires a thin structure with a broad angular and spectral response then the angles must be chosen so that higher orders cannot exist. This can begin when a and b both equal 30 degrees and the 2nd order becomes evanescent at 90 degrees (in air). The -1 order may still exist but is not entitled to receive much power at modulation levels near optimum for 99% diffraction efficiency (DE). When any of these gratings show excessive B error there is usually a preexposure fix that can be done to compensate or a post processing bake down or swell up for each material. A special case of this grating is the total internal reflection (TIR) geometry that requires extreme control over fringe tilt error. It should also be remembered that TIR gratings will not diffract P polarized light very well or at all for the same reason that Brewster's angle works. [[File:phasefig1.gif|Figure 1 Image]] '''Figure 1.''' The simple plane volume phase grating with properties: # sin a + sin b = λ/d # DE is proportional to sin²(ΔnT) and to 1/λ cos a + cos b) # Power lost to higher orders is proportional to Δn² # Fringe or Brag tilt B is proportional to T and n Figure 2 shows a common variance on a plane grating, a grating with a spatially varying spatial frequency such that rays of a certain λ and a common input direction will be diffracted to a common point on the output side. We may have seen this in text books as an off axis equivalent lens which is generally assumed to be a practical application of holography. For the fast optic shown, the output could be a family of points, half of them virtual and half real and all related geometrically to the fundamental focal length. Note that from top to bottom the spatial frequency (f₀ = 1/d) varies from very low, perhaps 200 l/mm to very high, perhaps 2000 l/mm. In the plane grating we only had to consider the modulation product of nT but now we have to add the term f₀ which also modifies DE. Note also that higher orders are nearly impossible to suppress at the top of this HOE and are nonexistent at the bottom. How would you ever make this design work? What material could be used? The difference in spatial frequencies could be compensated for in most materials by adjusting exposure energies in some way so that the lower end received less exposure and so create lower modulation than the top. This would solve the modulation balance except that now even more energy will be lost in the higher orders for only a small gain in the +1 because the losses at the top are proportional Δn², which just went up. Then perhaps the better fix is to try to keep n constant and vary the T from top to bottom such that the product of ΔnTf₀ is everywhere the same. Obviously you cannot buy such a material commercially so this special coating is very experimental. The processing will also have to be tailored because it is not likely that the thicker portions can be processed in the same time frames as the thinner portions. What about real time materials that saturate? Perhaps if available in liquid form, this HOE could be made. As the f# goes to 2.5 or higher this lens becomes a fairly good performer in most materials, only the really fast f#1 and lower optics are an art to construct and are probably best made in pieces if possible. An on axis lens made in any volume material at any f# will have a dead zone in the middle where almost no light can be diffracted because the spatial frequency falls to zero. One way around this dilemma is to work with a material that forms a surface phase structure at low spatial frequencies so that the HOE transitions from a surface phase HOE in the center to a thin and then thick phase HOE as the radial distance increases. A few materials will do this to some degree. [[File:phasefig2.gif|Figure 2 Image]] '''Figure 2.''' The case of a fast off axis focusing HOE with these additional properties: # DE varies from top to bottom if ΔnT is a constant. # Bragg or fringe tilt error is typically not uniform. # Higher orders often rob power from regions of large d spacing such as near the top. # S + P (random polarization) efficiencies cannot be as high at the bottom as in the middle. Figure 3 depicts a simple slanted reflection grating, if it were unslanted we would call it a conformal mirror with about the same properties found in dielectric stack mirrors. All reflection HOEs share one advantage over all transmission HOEs, the efficiency just keeps going up with increasing modulation rather than cycling up and down. The suppression of higher orders is also better at high n but the fringe spacing is a new variable affecting color and fringe tilt and it is nearly impossible to record an off axis reflection HOE without also recording a fairly strong transmission HOE. The idea of suppressing the unwanted transmission HOE by somehow index matching it out is only wishful thinking. The plane where the fringes meet the substrate must necessarily contain the same periodic changes in index that makes the HOE efficient, so the only case where a transmission HOE is not formed is the special case of the conformal reflector. This effect is of course minimized in materials of low n that rely on significant T to get sufficient modulation. In an HUD design the surface grating produces serious flare light when flying at certain angles to the sun, for that reason alone, practically all holographic HUDs are conformal reflectors. [[File:phasefig3.gif|Figure 3 Image]] '''Figure 3.''' The simple reflection grating with the properties: # DE is proportional to ΔnT. # λ is proportional to nT + any gradient in d spacing. # Δλ is proportional to Δn + any gradient in d spacing. # Surface grating strength is always non zero except for a conformal reflector. # power lost to -1 and higher orders is usually negligible even at high Δn Figure 4 is an illustration of a fast focusing reflection HOE. In this case the surface grating changes from high to low frequency but the reflection grating is more or less constant everywhere so that the efficiency is high every where. The efficiency falls off for P polarized light when the internal angle of diffraction or reflection approaches 90 degrees so if this is important to the design a denser material would be better than a less dense material. As the average n (roughly equivalent to density) of the film falls to low values the internal diffraction angles grow larger and account for many HOE failures. One of the errors this geometry is prone to is a variable fringe spacing and tilt induced by processing. Occasionally the distortion in the fringe structure is so large that constructive wave coupling fails and the HOE loses nearly all efficiency in spite of a large modulation level. Often the color is variable across the surface indicating a non uniform internal d spacing or average n. Hoes exhibit more severe aberrations in the reflection mode compared to the transmission mode, much like conventional optics. The choice of materials and processes to control them is particularly important when designing reflection optics or reflection art work. Full color display films have to have the required sensitometric characteristics as well as true reconstruction characteristics and only a few do. There are none that do it all with high efficiency but that is not a show stopper for anything but multi-wavelength notch filters and such which can usually be made with some other material. [[File:phasefig4.gif|Figure 4 Image]] '''Figure 4.''' The very fast non conformal reflection HOE with the properties: # DE is proportional to ΔnT # λ may vary with position from process induced distortions. # Surface grating can be very intense, producing a "transflection hologram." # Higher orders are suppressed much better than in transmission equivalent with mirror backing. ===Surface phase recordings.=== Figure 5 is a representation of the surface profiles common to diffractive optics, each has been recorded in one or more phase materials and copied in many more phase materials. The single biggest advantage of surface phase structures is that they can be replicated in a dozen or more ways that do not involve the use of lasers. In fact many are made as originals without laser light or at least without interference effects. Since they can often be made optically with lasers we have to consider them and mention the common materials with their properties and uses. The three most common surface profiles are shown as sinusoidal, square and sawtooth. The sinusoidal are natural continuous phase interference patterns, the square waves could be made by interfering a lot of odd harmonics in phase but are better copied from masks generated in typeset machines or on chrome masks exposed to E-beams. The sawtooth is deeper and is sort of the equivalent to a single side band transmitter with a suppressed carrier. This shape or its interferometric equivalent which appears more rounded is the only one that puts nearly all the light into one order. An exception to this is the deep square or sinusoidal grating that is high enough in spatial frequency to have no possible higher orders and is deep enough to have some volume type wave coupled interaction that results in high efficiency. The sawtooth shape has long been machined into materials to form blazed gratings for spectroscopy and now diamond turned blazed zone plates have become common on plastic lenses where the hybrid is effectively color corrected and has reduced spherical aberration. The blazed zone plate may also be made with a single exposure through a gray scale mask in photo-resist, in some photopolymers and with lesser performance in silver grain and DCG films. It is also made in the stepped mask manner where a multilevel stair case approximation to a blaze is achieve by using from 2 to 4 masks in sequence to expose the resist. This method is limited by mask resolution and alignment and by the wavelength of light used. If the grey scale mask or its binary equivalent can be used then it is only a one step exposure limited only by the mask resolution. This general class of optics includes binary optics, embossed rainbow holograms, embossed full parallax holograms, kinoforms and all other DOEs that are not volume HOEs (VHOES). [[File:phasefig5.gif|Figure 5 Image]] '''Figure 5.''' The general surface phase structure with the properties: # Angular bandwidth (Δθ) is much larger than in volume holograms or VHOEs. # Power distribution in higher orders is a strong function of fringe shape and depth T. # T is roughly equivalent to Δn and depends on n, except for metalized reflective shapes where air is the phase shifter. # Computer generated DOEs, lithographic or machined, are now common and practical, HOEs still rule at high f₀,(pun intended). ==Matching materials== The broadest class of phase recording materials would fill a book or two so we only want to consider generic silver grain films, DCG, Polaroid photopolymers, Dupont photopolymers, PVA, PVK and Shipley photo-resist. Reference texts and papers are listed in the bibliography for recipes and other details. The new book edited by Hans Bjelkagen entitled Holographic Recording Materials is the most comprehensive single source for valuable practical material information. It is a milestone series containing 676 previously published papers covering all but PVK and PVA. Many of the papers listed separately in my bibliography are in his book. ===Silver-Halide in gelatin=== By far the most popular materials to work in are products from Agfa, Kodak and a handful of smaller producers around the world. Some are panchromatic, some have extremely fine grains, all are comparatively fast and a few have been made to work in the near IR. They are the first choice of most artists because of the sensitivity to commonly available lasers of all colors and because they may be repeatably exposed and processed to produce the widest range of visual effects. The upper range of n is on the order of .1 and the grain size varies from a low of about 10 nm to over 100 nm. Grains are a significant source of scatter and therefore produce noise in the recordings, especially at short wavelengths. This is a major consideration for most applications and for all but the smallest grain films. Just about any HOE and some DOEs may be made in silver films but they will rarely be optimized for any enough properties and if they are bleached to get the highest efficiency then other sources of noise begin contributing and grain size may grow as well. A well worked out plan for a product may utilize the speed and panchromatic properties to produce a master HOE that can then be contact copied into a material with appropriate final properties. These films can be left as clean amplitude holograms or converted to "no silver halide in gelatin" (SHG) with simple chemistry and the resultant optic will be free from scatter caused by the grains of silver. The SHG masters are especially good when copying in the blue region where the lower n works well and silver grains often produce excessive noise. A good example is the making of a HOE like figure 2 that must perform well at 680 nm. If it were made at any other wavelength than 680 it would play back with aberrations so we either have to precompensate for those aberrations or make a master at 680 nm. Both Agfa and Kodak make films that are sensitive to 680 nm and that can also readily be processed into SHG masters with a simple weak chrome bleach followed by a fix and some hot alcohol baths. Then the master can be copied at 488 into DCG or a suitable photopolymer or the much slower photo-resist. Display masters may also be made this way, taking advantage of the speed of silver (as low as 3 µj/cm²) and then creating a photo-resist submaster in a more stable set up using 442 nm light. Contact copies of even a weak hologram can be very bright when transferred to DCG provided that the ratio of reference to object light is no less than 10:1 at the bright points and the scatter from all sources is very low. We highly recommend this general procedure for any exposures that have to be made at wavelengths longer than 514 nm to about 750 nm. Diode lasers can easily be made to operate in a single mode for long enough to make a good recording and Ion lasers or cadmium lasers can do all the copying. ===DCG (dichromated gelatin)=== By far the most versatile of the phase materials, DCG in its simplest form can be used to create almost any type of HOE as long as the exposure is allowed to be done at blue green or shorter wavelengths. A few people have even made good quality HOEs with dye sensitized DCG aka DSDCG, using krypton red or big HeNe lasers. The disadvantage there is the low sensitivity of the material and low availability of strong red sources. DSDCG may require from 50 to 1000 mj/cm² @ 647 nm while DCG can be used with as little as 4 mj/cm² @ 442 nm to about 100 mj/cm² @ 514 nm. In general all the photopolymers and all the photocrosslinkers are at least 1000 times less sensitive than silver halide products. We are fortunate that low scatter can be had from both mediums or else copying from one to the other would be useless. The intrinsic noise from a highly efficient DCG HOE of moderate thickness in the 5 to 8 micron range is 1 or 2%, a very low number. The sources of noise can be controlled to that level for simple grating like structures but surface noise from dirty beams, intermodulation noise found in multi-beam or diffuse object recordings, dust on and in the film and nonlinearity noise through the bulk can all contribute to the best of the materials and not all noise sources can be eliminated. The two greatest advantages of using DCG are the intrinsic low scatter, (if hardened sufficiently), and the tolerance for many reprocessing or post processing steps to fine tune the end product. The biggest disadvantage is that you have to devote time and space to a clean coating facility and the end product is extremely sensitive to high humidity. Some products require a careful tailoring of the thickness and juggling of the sensitizer and in those cases the requirement to coat your own is a big advantage. We work with standardized mixtures and coating methods that produce 5, 8, 10 and 25 micron thick coatings that have been sufficient to make almost any HOE for the visible and near IR regions, from 450 to 1500 nm. When the material is used without much hardening it produces hazy holograms that exhibit broad spectral and angular bands but as it is hardened it also narrows and at some point it crosses into the no scatter zone quite suddenly, with no attendant change in other properties. This point is where even unexposed gelatin can no longer be dissolved out with warm water, leaving scattering centers behind. At all levels of hardness the Δn near the surface can be pushed to .25 but as in most other media that number can not be extrapolated to thicker films. Films as thick as 100 microns have been made and processed but they behave no differently than 50 micron films which in turn behave thicker than 25 micron films but have a ΔnT product that is actually lower than what is achievable at 25 microns. We think 25 to 30 microns is about the practical limit for HOEs made in DCG, which means notch filters made in DCG can trade off bandwidth for density up to that thickness but top out at a ΔnT product of about 2.5, no matter how thick or thin the film is. DMP-128 from Polaroid tops out at about 2 also, bleached silver film is about .7, PVA is about .8 after wet processing and dupont products go to at least to 1. DCG has been used successfully with all the basic configurations, including the surface relief structures. For spatial frequencies below 500 l/mm DCG and silver halide films both form efficient surface relief profiles. This works best with softer gelatin and in silver film is enhanced by repeated bleach and develop steps. In DCG the effect is enhanced by using thick film and a longer soak in a .86 SG alcohol and water mixture before final dehydration in straight alcohol. Fixing after the first processing can improve the gel hardness without destroying the relief image and then the gel can be used as an embossing master with solvent softened plastics. Hardened silver halide films work about as well. The problems related to non uniform spatial frequencies or just non uniform exposures can be fixed if they are only off by 10 or 20% by post processing DCG in baths of hot soapy water and in fixer where areas that require more modulation are dipped in hot water and areas that are too well done can be brought down with fixer. Local zones may be repeatedly painted with fixer or a 5% solution of TEA and then reprocessed in water and alcohol to balance out the plate. If an area is known to be over exposed before processing, it may be effectively unexposed with an ordinary incandescent light bulb held close to it for a few minutes. All of these manipulation methods are experimental and the rules are loose and vary greatly from thick to thin in time and intensity. Baking at about 150 C will cause the gelatin to densify and if tilted fringes are present they will appear to lay down, baking also makes the gel much more stable and a little less hygroscopic. While it is still hot a glass cap or at least an epoxy coating can be applied without trapping too much moisture in the film. Trapped moisture can become active upon heating and cause the gel to collapse here and there and everywhere. Mysterious color shifts in capped reflection holograms can be explained by the action of trapped moisture and lack of 150 bake down. The sensitivity to moisture is not the only drawback to using DCG. It will easily distort in thick films and in large area recordings in thin films it is very difficult to process uniformly. The processing leaves the fringe planes at slightly random positions and usually the film expands so that the fringes stand up while the bulk n goes down. In gratings made at near 64 degrees in and out for either reflection or transmission the diffraction efficiency for incident P polarized light is near zero, because n has dropped to about 1.3. Unless you were building a polarization separator you would not find this desirable. In fact the low n means that the difference between S and P efficiencies is always larger than in more dense media. DMP-128 also has a low average n for about the same reason, the Δn is created by producing low density voids in the film during dehydration, much like the making of aerogels. ===DMP-128 photopolymer from Polaroid=== This film has enjoyed success as a flexible film used for great looking reflection and transmission display holograms. It is also useful for making high density reflectors and because of the unique open structure it can be filled with liquid crystals to make disappearing HOEs and DFB lasers and narrowband filters. It is easier to stabilize than DCG and has about the same high modulation in films of 7 to 15 microns. All of the wet processed films seem to work best in the thickness range of from 5 to 15 microns, probably owing to limited diffusion rates in DCG and in DMP-128. This material is used mostly with red light but can be made panchromatic more easily than DCG and is much more sensitive, requiring only about 25 mj/cm² to fully expose. This material is saturable, once the polymerizeable material is used up the effects of exposure are nil. This is a great advantage in production because over exposure has almost no effect, except to maybe compress the contrast range a little. This is true of all the migratory photopolymer systems, including all of Dupont's photopolymer products. The light used to expose the hologram need not be perfectly uniform to get a uniform copy. The ratio of the reference to object wave is the primary determinant of how much modulation an area will have after an over exposure. It is a sort of self "dodging" film with a hard limit on modulation related to beam ratio. This implies that to get maximum performance a reflection or transmission master has to be as bright in its hot spots as the reference. One disadvantage of this material is that it is on a substrate that has a higher index than the unexposed film so that all recordings have a mirror in them and the film is not generally available in liquid form as of this writing. Environmental controls are important at the exposure station, because the film has to be activated by a fairly precise percentage of water or it will produce noisy holograms. The low average n may be a disadvantage for some HOES and the material tends to shrink during or after processing and needs to be babied a little to get it to reconstruct with perfect fidelity. The display holograms are the best and brightest among the mass produced products and last a very long time. Polaroid has announced the introduction of another photopolymer that also has a high n but needs no wet processing and therefore is much more suitable for precision HOE making. It will be a great boon to some of us if they market the film as Dupont does, coated and in liquid form. I don't have a clue about how it is used or how well it performs. Photopolymers, because of the dynamics of monomer migration, may make pretty poor sequential hologram recordings, each successive shot adds noise to the previous shot, and if angles are not changed sufficiently between shots in a real time material then more than one recording will be made at a time as previous recordings reconstruct and rerecord with new ones. Latent image recordings do not have this problem and some real time materials do not have migration occurring. The little things can get you. ===Dupont Photopolymers=== These are all real time recording materials with migration of monomer. They work as is or may be enhanced with post exposure baking and with the addition of a monomer to swell them to a thicker state. Swelling shifts playback color and angle in reflection holograms. The sensitivity of some films is down to a few mj/cm² but as with DMP-128 they cannot be over exposed. Some films are panchromatic and good full color holograms can be made in them. The available Δn is about .06 on a good day in the best of films so to get good brightness the films are over 8 microns thick, more typically about 20 microns. They play back with smaller bandwidths but look clear in about any light. The normal backing is mylar and is birefringent causing some problems with production and making it difficult to make HOEs with high integrity. The liquid film has been made available so that it can go on glass and then good quality HOEs are possible. A very large number of display holograms have been produced in this material, which is sold in sheets and rolls with machines to expose and process it. The limited modulation prevents this material from being used in some tasks, but it is a big plus for others. When high angular selectivity or a narrow notch filter is needed it is the material of choice, especially if you can get coatings of 50 microns or more. Optical memories have been made with it and could flourish. We made diffraction limited gratings with it. The dye never bleaches all the way out of some of their films so it is useless at short wavelengths, as is DCG and PVK. Most if not all holographic recording materials naturally absorb strongly in the UV region both long and shortwave. One of Dupont's materials forms an excellent embossed surface upon exposure and is great for copying binary or possibly shaded masks. The shading may copy with poor linearity depending on light intensities, spatial frequencies and migration rates and distances, all considerations that could spoil your day. We copied a binary mask in non embossing material and found that it was self guiding because of the real time formation of the higher index light fringes. The first light through the slits forms a guide for the rest and the usual diffractive spreading does not occur and the copied HOE is excellent except for the plastic substrate it is usually on. This is very easily used material, and stores for years in a fridge. ===PVA and PVK=== PVA (polyvinyl alcohol) has been dichromated and used as a real time material fixed with heat for many years. It is easy to get, mix, coat and use this way. It is also possible to enhance the modulation greatly by dipping it in water and alcohol, similar to DCG processes. It can also serve as a binder for a monomer and act more like other photopolymers. In its dichromated form it is a photocrosslinker like DCG and as such has no migration but the latent image in PVA is many times better than the latent image in DCG. Images and HOES are easily seen as they form in films as thin as 5 microns. The integrity of the recordings is very high with very little damage done by overwriting multiple times. As a crosslinker it is not a saturable media and can be overexposed, however it requires about a 100 mJ/cm² to form a strong recording and about 1000 more to begin to undo it. One disadvantage is that it does not adhere well to glass or plastic which makes it a perfect candidate for a transfer hologram. It is possible to form a conformal mirror in it on flat glass or plastic in a production environment and then lift it off and transfer it to a spherical surface in another off line process. It is soluble in water and unstable at high humidity but it may be possible to stabilize chemically by converting at least some of its molecules back into polyvinyl acetate or by adding crosslinking agents to a last bath. Borax is used to crosslink PVA and form "slime", baking a wet processed PVA hologram causes it to return to its original latent image state and stabilizes it somewhat against moisture. Other uses include protecting and cleaning optics and it is a common mold release agent. PVK (polyvinyl carbazole) is not soluble in water but dissolves in chloroform and in sensitized by halogens to become a photocrosslinker. It is processed in xylene and hexanes or a mono bath of miscible but differentially volatile solvents. It should only be used where maximum resistance to water is needed. It will work well in 5 micron layers, has a short shelf life and a high Δn but is hard to process uniformly. It is sensitive to blue green light and requires only a few mJ/cm². It requires the use of noxious chemicals, some of which are known carcinogens. PVK is also a commonly used photoconductor which could be used to form relief holograms in thermoplastics and for light intensifiers. If used for holography it has to be sensitized at the same time it is dissolved or it will not work, the fastest sensitizer is carbon tetra iodide and it is extremely unstable. ===Shipley Photo-resist=== Many of us use this as a standard for embossing masters. It can be obtained on plates commercially from several sources, has a long shelf life, and reasonable sensitivity to blue and UV light. We have jars of material that are 20 years old and still work about as well as they ever did. This is the most common material used to make binary optics from metal masks and it is easily metalized for production of embossing shims. We make masters from epoxy molds lifted from the resist and then mold copies in other epoxies and plastics. It is possible to make features as deep as 4 or 5 microns with little effort and resist masters may be directly converted to glass masters with reactive ion etching or with diluted HF. Some people are able to get very high aspect ratios in it and form high frequency high efficiency gratings in it. The integrity of the recording is rarely compromised in processing, but very high frequency gratings may close over at the top if the are exposed to common organic solvent fumes. Resist is user friendly and you never have to even dim the lights while working with it. All surface phase DOEs and HOEs are readily made in this material. It is often advisable to make a clean master in DCG to copy from because the exposures for reasonable sizes copies can run from several minutes to an hour, during which time a contact copy on three legs may not move but most optical setups of any size will. The required exposure is on the order of 2000 mJ/cm² @ 488 nm. Clean glass and primers and bakeouts are sometimes necessary to keep the resist on the glass and since most resists used are positive, exposure to UV after processing will break bonds and leave the material prone to falling off when you least want it to. There is a lot more to be said about designs and materials but no more room or time to say it. ==Relative material sensitivities== [[File:delta_n.gif|Average Delta n 8 microns vs. Exposure Energy in mJ/cm²]] ==References== # H. Kogelnik, "Coupled wave theory for thick hologram gratings" <em>Bell Syst Tech J. </em> <strong>48</strong>:2909-2947 (1969) # T. K. Gaylord and M. G. Moharam, "Analysis and applications of Optical Diffraction by Gratings" <em>Proc. of IEEE</em>, <strong>73,</strong> (5) (May 1985). # J.N. Cederquist and J.R. Fienup,"Analytic Design of Optimum Holographic Optical Elements" <em>J Opt Soc Am A</em><strong>4</strong>:699-705 (April 1987) # E. Hasman and A.A. Friesem, "Analytic Optimization for Holographic Optical Elements". <em>J Opt Soc Am A</em><strong>6</strong>:62-72 (Jan 1989) # F. T. S. Yu. "Effect of Emulsion Thickness Variations on Wavefront Reconstruction". <em>App Optics</em><strong>10</strong>:1324-1328 (June 1971) # R. D. Rallison "Incoherent Multifocus Hololens design and fabrication", <em>Proc. SPIE </em><strong>1183</strong>:663-668 (1989) # M. Chang and N. George, "Holographic Dielectric Grating; Theory and Practice" bibliog diags <em>Ap Optics</em><strong>9</strong>:713-719 (March 1970) # T.K. Gaylord and F. K. Tittel, "Angular Selectivity of Lithium Niobate Volume Holograms",<em> J. App Phys</em> <strong>44</strong>: 4771-4773 (Oct 1973) # J.N. Latta, "Computer-Based Analysis of Hologram Imagery and Aberrations", <em>Ap Optics</em> <strong>10</strong>:599-618 (Mar 1971) # Y. Amitai et al "Holographic Elements with High Efficiency and Low Aberrations for Helmet Displays", <em>Appl Opt </em><strong>28</strong>:3405-3416 (Aug 15 1989) # Y. Ono and N. Nishida "Holographic Zone Plates for f'0 and Collimating Lenses", <em>Appl Opt</em> <strong>25</strong>:794-797 (Mar. 1986) # J.R. Fienup "Iterative Method Applied to Image Reconstruction and to Computer-Generated Holograms", <em>Opt Eng</em> <strong>19</strong>:297-305 (May 1980) # M.R. Latta and R.V. Pole "Design Techniques for Forming 488-nm Holographic lenses with Reconstruction at 633 nm", <em>App Opt </em><strong>18</strong>:2418-2421 (July 15 1979) # E. Wihardjo, et al "Compensation of Wavelength-Shift Aberrations in an off-axis Holographic Zone Plate", <em>Opt Eng</em> <strong>25</strong>:871-874 (July 1986) # <em>Holographic Optics: Design &amp; Applications. </em>Cindrich, ed<em>. SPIE press</em> (1988). # R.C. Fairchild and J.R. Fienup, "Computer Originated Aspheric Holographic Optical Elements", <em>Opt Eng</em> <strong>21</strong>:133-140 (Jan/Feb 1982) # D. A.Winick, "Thick Phase Holograms", Environmental Research institute of Michigan, Level, (January 1981). # L. Solymar &amp; D.J. Cooke , <em>Volume Holography and Volume Gratings</em>, Academic Press, (1981). # Felix P. Shvartsman and Moshe Oren, "Photo-lithographic imaging of computer generated holographic optical elements" <em>Proc. SPIE <strong>1555</strong></em>:71-78, (1991). # A.J. Lee and D. P. Casasent,"Computer-Generated Hologram Recording Using a Laser Printer", <em>Appl Opt</em><strong>26</strong>:136-138 (Jan 1 1987) # Steven M. Arnold, "Desktop computer encoding of electron-beam written holograms" <em>Proc. SPIE </em><strong>884:</strong>23-27 1988. # R. D. Rallison , "Wavelength compensation by time reverse ray tracing", <em>Proc. SPIE </em><strong>2404</strong>: 217-225 (1995) # G. D. Mintz, D.K. Morland &amp; W.M. Boerner, "Holographic Simulation of Parabolic Mirrors", <em>Applied Optics,</em> <strong>14</strong> (3):564-570 (March 1975). # Hans Dieter Tholl "Polarization properties of volume phase gratings", Optical Engineering, <strong>34</strong>(10)2879-2885 (Oct 1995) # W. S. Colburn &amp; B. J. Chang "Holographic Combiners for Head-Up Displays", <em>Technical Report AFAL-TR-77-110</em> (Jan 1977). # Ryszard Gajewski "Holographic Technology for Solar Energy Concentration" <em>Technical Report No. 87-1479</em> (July 1984). # Jose R. Margarinos &amp;Daniel J Coleman "Holographic Mirrors" <em>Proc. SPIE </em> <strong>523</strong>:203-218 (1985). # Richard D.Rallison, "Holographic Optical Elements (HOES) in Dichromated Gelatin (DCG)", <em>Proc. SPIE</em> <strong> 523</strong>:292-295 (1985). # Jon D. Masso "Multilayer Thin Film Simulation of Volume Holograms" <em>Proc. SPIE</em> <strong>883</strong>:68-72 (1988). # H. M. Smith, <em>Holographic Recording Materials</em> Springer Verlag, 1977 # H. I. Bjelkhagen, <em>Silver-Halide Recording Materials for Holography</em>, Springer Verlag, 1995 # R. D. Rallison, "Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug.(1987) # T. A. Shankoff, "Phase holograms in dichromated gelatin" Appl. Opt. <strong>7:</strong>2101-2105 (1968) # Hans I Bjelkhagen, <em>Holographic Recording Materials</em>, SPIE publications, 1996. # R. D. Rallison "Survey of properties of volume holographic materials", <em>Proc. SPIE</em> <strong>1051</strong>:68-75 (1989) # J. L. Salter and M. F. Loeffler, "Comparison of dichromated gelatin and dupont HRF-700 photopolymer as media for holographic notch filters" <em>Proc. SPIE </em> <strong>1555</strong>:268-278 (July 1991) # R.A. Bartolini, "Characteristics of Relief Phase Holograms Recorded in Photoresists"<em>App Optics</em> <strong>13</strong>:129-139 (Jan 1974) # Tung H. Jeong, <em>Proceedings of the International Symposium on display holography,</em> Vol I (1983) # Tung H. Jeong, P<em>roceedings of the International Symposium on display holography</em> Vol II (1986) # D.J. Lanteigne and T.D. Hudson, "The DMP-128 Holographic Cookbook" Technical Report RD-RE-86-14 U.S. Army Missile Command, Nov. 1986. # J. C. Kirsch, D. J. Lanteigne and Don Gregory, "An investigation into DMP-128 Holographic Recording Material" Technical report RD-RE-87-1 U.S. Army Missile Command, Feb 1987. # D.H. Close and A. Graube, "Materials for Holographic Optical Elements", Technical Report AFML-TR-73-267, Oct. 1973. # B.J. Chang, "Post Processing of Developed Dichromated Gelatin Holograms", Opt Comm, <strong>17</strong> (3): 270-271 (June 1976). # T. Kubota, T. Ose, M. Sasake and K. Honda "Hologram Formation with Red Light in Methylene Blue Sensitized Dichromated Gelatin" <em>Applied Optics,</em> <strong>15</strong>(2):556-558 (Feb. 1976). # S.P. McGrew, "Color Control in Dichromated Gelatin Reflection Holograms", <em>Proc. SPIE </em><strong> 215</strong>:24-31 (1980). # R. T Ingwall, M Troll and W. T. Vetterling "Properties of Reflection Holograms Recorded in Polaroid's DMP-128 Plotopolymer" <em>Proc SPIE</em> <strong>747</strong>:67-73 (1987). # R. D. Rallison, "Control of DCG and non silver holographic materials" <em>Proc SPIE </em> <strong>1600</strong>: 26-37 (1991). ''Last modified on 9/16/97'' [[Category:Rallison]] ba438f0a35555c58a22d4086db3803c6f6289a78 0 814 1616 2013-05-11T16:45:34Z Admin 0 wikitext text/x-wiki * [[Additional use for Fringe Locker | Additional use for Fringe Locker]] * [[Bibliography | Bibliography]] * [[Blazed binary optics, from pc to plastic | Blazed Binary Optics, From PC to Plastic]] * [[Changelog for Ralcon Development Lab web page]] * [[Circle To Point Converters]] * [[Circle-to-point conversion and Optical rotary joints]] * [[Contact Information, Facilities, Materials, and Ordering Information]] * [[Control of DCG and non silver holographic materials]] * [[DCG References]] * [[History of Dichromates]] * [[Directional Diffusers]] * [[Equations | Dirrectional Equations]] * [[Resume of Richard D. Rallison | Experience (Resume)]] * [[Fringe Locking]] * [[About Ralcon Development Labs | General Information About Ralcon Development Labs]] * [[HOE Kit | HOE Kit Information]] * [[Hoes and Does | Hoes and Does Information]] * [[Holotool Contents | Holotools]] * [[Index for DCG and other phase materials]] * [[Instructions for Getting Here]] * [[Links]] * [[Polarization properties of gelatin holograms]] * [[2 and 3 Color Dichromates | Pseudo-color Techniques]] * [[Publications]] * [[Ralcon Development Lab | Main page]] * [[Recording Material Selection]] * [[Stability Issues in DCG]] * [[Time Reverse Ray Tracing]] * [[HOE Tutorial | Tutorial]] * [[VHOE Relationships]] * [[Wavelength compensation at 1.064µ using hybrid optics]] * [[What's Happening]] * [[Zone Plate Equations]] ''Last modified on 1/14/01'' [[Category:Rallison]] d7fd3358bc5c793ed0f2666cb2d7e1f13a98b54e 0 405 1740 962 2013-05-11T21:21:48Z Admin 0 /* Links */ wikitext text/x-wiki A knife is a broad word encompassing a large number of tools. The cheapest knife to buy and maintain is an x-acto knife. [[Image:XactoNo1.jpg]] The no. 1 knife handle with the no. 11 blade is the most common knife we associate with X-Acto but they make a broad product line for model makers. The blades are stainless and never get as sharp as a steel blade. [[Image:XactoX2000.jpg]] A more comfortable handle is the X-2000. X-Acto knife blades are cheap enough that sharpening is not required. The blades are simply replaced. [[Image:ViolinMakersKnives.jpg]] A better knife is a violin makers knife. You can sharpen the blade and trim back the handle for a lifetime. They are available in German steel and Japanese Steel. The German steel is more durable (chips less easily). The Japanese steel gets sharper and stays sharp longer but chips quite easily. ===Sharpening Knives=== Sharpening knives is a task of patience. You must completely sharpen one face to completion before moving on to a finer grit. You may stop at anytime the knife is sharp but what is described below will make a knife sharp enough to shave. [[Image:KniveAngles.jpg]] The angle you sharpen at is chosen based on what the knife will be used for. Use a blunt angle for rough work and a durable blade and use a sharp angle for delicate work. [[Image:KnifeSharpening.jpg]] *Rough out both sides in a single plane with a course stone. *Polish the faces with a fine stone. *Hone the knife on a leather strop with red compound (rouge). *Hone the knife on a 2nd leather strop with white compound. [[Image:KnifeSharpeningStages.jpg]] Tips: *Do not switch to fine grit until all chips have been removed. *Be careful to not round the edge. You need one plane from the shank of the knife to the edge. *Sharpen both sides evenly. Safety Tips: *Do not pull a knife towards your body or fingers. [[Image:KnifeSharpeningTips.jpg]] ===Links=== [[http://www.frets.com/FretsPages/Luthier/Technique/ToolUse/KnifeTechnique/knifetech01.html Master Luthier Frank Ford on Knives.]] 9d20ec5be60b326a2fd8c158fabd3f14da69036c 0 193 1614 234 2013-05-11T21:38:32Z Admin 0 wikitext text/x-wiki [[Image:Colink.jpg]] Colin Kaminski is an amateur holographer who in a state of extreme frustration and needing advice started the forum that has become the [http://www.holographyforum.org Holography Forum] and now this Wiki. He really has no other holography releated acomplishments other than about 100 or so 4x5" and smaller holograms given to children. He has worked as an Assembly Language Programmer, Motorcycle Mechanic, Luthier, Theatrical Lighting Designer, Product Designer and now he is the Master Brewer at [http://www.downtownjoes.com Downtown Joe's] in Napa, CA. [http://www.designerinlight.com Colin Kaminski's Web Site] [[Image:Colinemail.jpg]] [[Category:People]] ccf358ef9a84c56506af411ab376894057eabeb5 0 842 1774 2013-05-11T21:42:05Z Admin 0 /* Design and Fabrication of HOEs, DOEs and Hybrid optical systems.Specialists in Volume Holographic Optics (VHOEs) since 1974. */ wikitext text/x-wiki [[File:rallogo.gif|center]] [[About Ralcon Development Labs]] ==Design and Fabrication of HOEs, DOEs and Hybrid optical systems.<br>Specialists in Volume Holographic Optics (VHOEs) since 1974.== If you do not find the information you are after, try the [[Complete Site Map]]., send an email, or [[Contact Information, Facilities, Materials, and Ordering Information#contact|contact]] someone directly. {| border=1 |- | '''Information about Ralcon''' || '''Ordering Information''' || '''Papers and Publications''' |- | * [[About Ralcon Development Labs]] * [[Instructions for Getting Here|How to get here]] * [[Resume of Richard D. Rallison|Experience]] * [[Ralcon Development Lab|Facilities]] * [[Ralcon Development Lab#Materials|Materials]] * [[Instructions for Getting Here|How to Get Here]] * [[Ralcon Development Lab#Contact|Contact Information]] * [[Ralcon development Lab#Ordering|Ordering Information]] * [[Holotool Contents|Get Holotools here]] | * [[HOE Tutorial|Tutorial]] * [[Circle To Point Converters|Circle To Point Converters]] * [[HOE Kit|HOE Kit Information]] * [[2 and 3 Color Dichromates|Pseudo-color Techniques]] * [[Hoes and Does|HOES and DOES]] * [[VHOE Relationships|VHOE Relationships]] * [[Zone Plate Equations|Zone Plate Equations]] * [[Links|Links]] | * [[Publications|Publications]] * [[Fringe Locking|Fringe Locking]] * [[Recording Material Selection|Recording Material Selection]] * [[Stability Issues in DCG|Stability]] * [[History of Dichromates|History of Dichromates]] * [[Bibliography|Bibliography]] * [[History of Dichromates: DCG References|DCG Specific Bibliography]] * [[Media:DWDM-Dickson_grating_white_paper.pdf|Dickson Grating White Paper]] {392kB) |} '''For all inquiries and orders, please contact http://www.wasatchphotonics.com.''' [[File:wplogo_new_small.gif|center|Wasatch Photonics]] * [[What's Happening|What's New?]] (includes Employment Opportunities) * [[Changelog for Ralcon Development Lab web page|What's New on this Web Page?]] Please email comments about content to rdr@ralcon.com. This page hosted by Xmission. 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519c08da88276b2f47bc6fb30637d415fd0d804e 6 153 153 2013-05-12T02:46:42Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 154 154 2013-05-12T02:46:43Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 1 156 1 2013-05-12T02:51:20Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki '''MediaWiki has been successfully installed.''' Consult the [//meta.wikimedia.org/wiki/Help:Contents User's Guide] for information on using the wiki software. == Getting started == * [//www.mediawiki.org/wiki/Manual:Configuration_settings Configuration settings list] * [//www.mediawiki.org/wiki/Manual:FAQ MediaWiki FAQ] * [https://lists.wikimedia.org/mailman/listinfo/mediawiki-announce MediaWiki release mailing list] b7a3846f2c55072191227d89a3204fe379288fee 0 155 158 157 2013-05-12T02:51:20Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki == Biological Basis of Vision == ===The Human Eye=== Well-informed expositions on the biology and architecture of the human eye are available online, for example: [http://www.merck.com/mmhe/sec20/ch224/ch224b.html Online Merck Manual]. A broad article is available at [http://en.wikipedia.org/wiki/Eye WikiPedia]. A frequently cited reference on the retina from a neural/functional standpoint is Dowling (1987). The human eye is a direct extension of the brain; much more than a "biological camera," the eye performs pre-computation on observed imagery prior to transmitting it towards the visual cortex. In the words of Churchland and Sejnowski (1993), "[t]he primate retina transforms patterns of light on the 100 million photoreceptors into electrical signals on the mere one million axons in the optic nerve, and the 100:1 compression ratio suggests heavy-duty signal processing and information compression" (p. 148). One striking illusion that highlights visual precomputation, [http://studenthome.nku.edu/%7Edouglask/illusions/MachBands.htm Mach banding], is the incorrectly-perceived brightness at edges of differently-shaded fields. Although still incompletely understood, this may be due to lateral inhibition amongst nearby photoreceptors, resulting in high-pass filtering in the eye itself. ===Relevant Neural Regions=== In general, imagery from the right visual field (as collected by the ''left'' hemisphere of both eyes) is transmitted via the optic nerve and optic chiasm to the left hemisphere's optic tract; likewise, imagery from the left visual field travels along the ''right'' hemisphere's optic tract. We note that most of this flows to the thalamus's lateral geniculate nucleus (LGN), with another pathway to the superior colliculus. The information reaches the visual cortex, which is located at the back of the brain. The visual cortex has several regions: V1, V2, and so on, whose supposed function is beyond the scope of this discussion. However, we note two relevant and generally-supported hypotheses: '''Retinotopic Mapping in V1''' A striking series of experiments showed that regions of the visual cortex are mapped retinotopically to the observed field, that is, "neighboring cells have neighboring receptive fields" (Churchland & Sejnowski, 1994, p. 155). In a seminal experiment performed by Roger Tootell, a primate's brain was examined after fixation on a patterned bullseye-like target - when the brain was stained as a function of activity, an image of the target was clearly visible on the unfolded cortex (Tootell, Silverman, Switkes & De Valois, 1982). See a [http://neuro.med.harvard.edu/site/dh/114.jpg photograph here], from the Harvard website containing David Hubel's online vision textbook. [http://neuro.med.harvard.edu/site/dh/b23.htm section: The Architecture of the Visual Cortex.] '''Regions of V1 and V2 Correspond to Varying Degrees of Monocularity and Binocularity''' Churchland and Sejnowski (1994) state that: "For the brain to generate stereo vision, there must be means for the brain to compare retinal images ''relative to varying planes of fixation.'' Hubel and Wiesel (1963) discovered that striate cortical cells were not uniform in their response to a visual stimulus, but some cells were strongly monocular, and were flanked by other cells responding somewhat to stimuli from both eyes, though preferring one or the other, flanked in turn by cells that were binocular" (p. 197). See David Hubel's [http://nobelprize.org/medicine/laureates/1981/hubel-lecture.pdf 1981 Nobel Prize lecture]. Learn more about the visual cortex at [http://en.wikipedia.org/wiki/Visual_cortex Wikipedia]. == Depth Cues == Humans perceive imagery that falls on their retina(s) as three-dimensional when influenced by one or more ''depth cues.'' Monocular depth cues can be experienced with just one eye; binocular depth cues require two. === Monocular Depth Cues === Briefly, monocular depth cues include: *'''Relative size:''' larger objects are interpreted as being nearer the observer *'''Interposition / Overlapping:''' close objects tend to occlude far objects *'''Linear perspective (foreshortening):''' Receding parallel lines appear to meet at the horizon. *'''Aerial perspective (haze / fog):''' Blurry or foggy objects may be interpreted as distant, since haze usually blurs distant scene elements. *'''Light and shade:''' So-called "2 1/2-D" rendering uses the interplay of shape and light to suggest the three-dimensionality of objects. Note that people assume that light comes from above when viewing an image; this is the so-called ''light-from-above prior'' or ''light-from-above heuristic''. *'''Motion parallax:''' Horizontal observer movement (egomotion) "makes" near objects appear to move faster than distant objects. Note that this cue can be used to simulate egomotion, that is, in movies, animations, and true 3-D representations, moving foreground elements faster than background elements evokes the sensation of movement. *'''Accommodation (focus):''' Retinal focus provides information to your brain about the probable distance from your eye to the object you are fixating on. One issue of non-holographic 3-D displays is the so-called "accommodation / vergence conflict," in which the angular swivel of the eyes does not agree with their focus. This happens, for example, when watching a stereoscopic 3-D movie, since there are cases in which your eyes are focused at a distant screen while they are rotated inwards to gaze at a very close scene element. *'''Texture Gradient:''' As in a field of wheat, the perception of a textured region is a function of distance. A variety of [http://www.sapdesignguild.org/resources/optical_illusions/index.html optical illusions] prey upon the assumptions your mind makes about interpreting monocular depth cues. ===Binocular Depth Cues (Stereopsis)=== The average interpupillary distance is approximately 6-6.5 cm. In normal circumstances, this leads to each eye observing a different 2-D field. The brain interprets these differences for depth information, such as (De Valois & De Valois, 1990): *'''Vergence:''' The angular "swivel" of the eyes while gazing at an object provides a strong cue regarding the depth of that object. *'''Positional Disparity:''' A large-scale illustration of positional disparity is observed by holding one's outstretched index finger and observing the relative motion of your finger and the background when viewed alternately by your left and right eyes. [http://en.wikipedia.org/wiki/Stereopsis Wikipedia: Stereopsis] *'''Phase Disparity of Frequency Components:''' There is evidence suggesting that the brain is sensitive to the phase difference of the frequency components of an image, which has a different magnitude, of course, than displacing the sine wave component itself (De Valois & De Valois, 1990, p. 302) *'''Orientation Disparity:''' Orientation disparity refers, for example, to the different angle a line makes on each retina when gazing at a line pitched toward or away from the observer. *'''Spatial Frequency Disparity:''' The separable existence of this cue may still be in debate. Spatial frequency disparity is the difference in spatial frequency for scene elements that are, for example, at varying depths from the observer (Halpern et al, 1987). For example, pitching a single-frequency grating at an angle to the observer yields different perceived spatial frequencies in each eye (De Valois & De Valois, 1990, p. 307). The collection of potential disparities are called ''stereopsis.'' '''An Implication of Random-dot Stereograms''' Note that the brain does not require local stereopsis to perceive depth; global stereopsis "can occur without monocular contours" (De Valois & De Valois, 1990, p. 314). For example, Julesz's (1971) random-dot stereograms present two views that appear, in a monocular sense, like disorganized spatial noise. However, the brain is able to fuse the two images into a scene containing depth - perhaps via the global low-freqency content in the imagery. ==Guidelines for Effective 3-D Imagery== ===Rules of Thumb for Particular Display Media=== One implication of the preceding discussion is that it is best to match subject matter to the display medium and intended observation environment. Experts in the following media are invited to add their own rules of thumb: * Holographic stereograms * Cylindrical multiplex holograms * Quasi-holographic electro-optical displays ===Bandlimiting Can Decrease Interview Aliasing=== Holographic stereograms and other discrete-"view" 3-D displays can exhibit motion artifacts due to interview aliasing. For example, image points far from the image surface appear to jump to neighboring views during egomotion if they are sampled or reconstructed improperly. Holography researcher Michael Halle (1994) discusses these constraints, which apply in particular to holographic stereograms and non-holographic parallax displays. In short, interview aliasing can be mitigated by intentionally blurring scene elements distant from the image surface. ===Understand Your Medium's Focus Characteristics=== Of course, different 3-D display media use different methods to reconstruct 3-D light fields. For example, some holograms are highly astigmatic, putting the horizontal and vertical foci at very different surfaces in or beyond the 3-D scene. The family of horizontal parallax only (HPO) holograms discards some or all vertical parallax information (De Bitetto, 1968; Benton, 1969; De Bitetto, 1969; Benton, 1977). The long-term effects of viewing astigmatic display media, such as HPO holograms, are not widely known in the display community, and references to thoughtful work in the area are appreciated. While not holographic, the variety of electronic 3-D display technologies also vary in their focus characteristics. They range from volumetric displays, whose true voxels in (''x'', ''y'', ''z'') space elicit proper vergence and accommodation cues (Favalora et al, 2005) to experimental "highly-multiview" HPO systems (Favalora, 2005) and lenticular-sheet displays which are HPO ''and'' typically project very discrete infrequently sampled horizonal parallax information. Members of the former MIT Media Laboratory's Spatial Imaging Group explore the importance of choosing the correct scene-sampling and reconstruction geometries as a function of factors including the intended observation point and propose computational predistortion methods for dealing with these issues (Halle, Benton, Klug, & Underkoffler, 1991). == References == <small> *Churchland, P. & Sejnowski, T. J. (1994). ''The Computational Brain''. Cambridge, Mass.:The MIT Press. ISBN 0262531208 *Benton, S. A. (1969). Hologram Reconstructions with Extended Light Sources, ''J. Opt. Soc. Amer. 59'', 1545A. *Benton, S. A. (1977). White-light transmission/reflection holographic imaging. In E. Marom, A. Friesem, & E. Wiener-Avnear (Eds.), ''Applications of Holography and Optical Data Processing'' (pp. 401-409). *De Bitetto, D. J. (1968, March 1). Bandwidth reduction of hologram transmission systems by elimination of vertical parallax. ''Applied Physics Letters, 12''(5), 176-178. *De Bitetto, D. J. (1969, August). Holographic Panoramic Stereograms Synthesized from White Light Recordings. ''Applied Optics, 8''(8), 1740-1741. *De Valois, R. L. & De Valois, K. K. (1990). ''Spatial Vision''. Oxford: Oxford University Press. ISBN 0195050193 *Dowling, J. E. (1987). ''The Retina: An Approachable Part of the Brain''. Cambridge, MA: Harvard University Press (Belknap Press?). ISBN 0674766806 *Favalora, G. E. (2005, August). Volumetric 3D Displays and Application Infrastructure. ''Computer, 38''(8), 37-44. [http://www.greggandjenny.com/gregg/IEEE_Computer_Favalora.pdf PDF] *Favalora, G. E., Chun, W., Cossairt, O. S., Dorval, R. K., Halle, M., Napoli, J., & Thomas, M. (2005), "Scanning optical devices and systems," U.S. Pat. App. US2005/0285027A1, filed Feb. 15. *Halle, M. W., Benton, S. A., Klug, M. A., & Underkoffler, J. S. (1991). The Ultragram: A Generalized Holographic Stereogram. In S. A. Benton (Ed.), ''Practical Holography V'' [Proc. SPIE-IS&T Electronic Imaging, SPIE Vol. 1461] (pp. 142-155). [http://citeseer.ist.psu.edu/halle91ultragram.html CiteSeer] *Halle, M. (1994). Holographic stereograms as discrete imaging systems. In S.A. Benton (Ed.), ''Practical Holography VIII'' [Proc. SPIE] Vol 2176, (pp. 73-84). Bellingham, WA. [http://splweb.bwh.harvard.edu:8000/pages/ppl/halazar/pubs/discrete_spie94_preprint.pdf Preprint PDF] *Halle, M. (1997, May). Autostereoscopic displays and computer graphics. ''Computer Graphics,'' ACM SIGGRAPH, 31(2), 58-62. [http://web.media.mit.edu/~halazar/autostereo/autostereo.html HTML and PDF versions.] *Halpern, D. L. et al (1987). What causes stereoscopic tilt from spatial frequency disparity. ''Vision Res., 27''(9), 1619-1629. *Hubel, D. H. & Wiesel, T. N. (1963). Shape and arrangement of columns in cat's striate cortex. ''Journal of Physiology, 165'', 559-568. *Julesz, B. (1971). ''Foundation of cyclopean perception''. Chicago: University of Chicago Press. *Okoshi, T. (1976). ''Three-Dimensional Imaging Techniques''. Academic Press. ISBN 0-12-525250-1 *Ratliff, F., Milkman, N., & Rennert, N. (1983). Attenuation of Mach bands by adjacent stimuli. ''Proc Natl Acad Sci U S A 80''(14), 4554-8. [http://radiology.rsnajnls.org/cgi/ijlink?linkType=ABST&journalCode=pnas&resid=80/14/4554 Abstract and Article PDF] *Shepherd, G. M. (2003). ''The Synaptic Organization of the Brain''. Oxford University Press. ISBN 019515956X *Tootell, R. B. H., Silverman, M. S., Switkes, E., & De Valois, R. L. (1982). Deoxyglucose analysis of retinotopic organization in primate striate cortex. ''Science, 218'', 902-904. </small> == External Links == * H. Kolb et al, ''[http://webvision.med.utah.edu/ Webvision: The Organization of the Retina and Visual System]'', John Morgan Eye Center, University of Utah (accessed 28 May 2006) * [http://www-staff.lboro.ac.uk/~mmtw/holopaperWeb.pdf Brief Survey on Three-Dimensional Displays: from Our Eyes to Electronic Hologram] 0d0184f021073a6f8b834fb259c5e1a9a0abd0cc 0 156 160 159 2013-05-12T02:51:21Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==Holography Glossary== [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Aerial perspective''' - the distance or depth effect caused by atmospheric haze. Haze creates a large amount of extraneous ultra-violet light to which all photographic emulsions are sensitive. *'''Acetic acid''' - chemical used for stop baths and to acidify acid fixing solution. *'''Acetone - solvent chemical used in certain processing solutions that contain materials not normally soluble in water.''' *'''Albumen paper''' - printing paper invented by Blanquart-Evrard in the mid-19th century where egg whites were used to coat the paper base prior to sensitization. The albumen added to the brightness of the white base and substantially improved printed highlights. *'''Allegory''' - work of art that treats one subject in the guise of another. An allegoric photograph usually illustrates a subject that embodies a moral "inner meaning". *'''Alum''' - chemical used in acid hardening fixing baths. *'''Aluminum compounds''' - groups of chemicals often used as hardeners in fixing baths. *'''Ambrotype''' - Mid-19th century photographic process introduced in 1851-52 by Frederick Scott Archer and Peter Fry. It used weak collodion negatives which were bleached and backed by a black background which produced the effect of a positive image. *'''Amidol''' - soluble reducing agent which works at low pH values. *'''Ammonium chloride''' - chemical used in toners and bleachers. *'''Ammonium Dichromate''' - chemical used as a sensitizer in Dichromated Holograms. *'''Ammonium persulfate''' - chemical used in super-proportional reducers. *'''Ammonium sulfide''' - pungent but essential chemical in sulfide or sepia toning. *'''Ammonium thiosulfate''' - highly active fixing agent used in rapid fixing solutions which works by converting unused silver halides to soluble complexes. *'''Amphitype''' - Mid-19th Century process based on an underexposed albumen-on-glass negative. This was viewed by reflected light against a black background to give a positive image similar to a ambrotype. *'''Anaglyph''' - result of forming stereoscopic pairs from two positives each dyed a different color, usually green or red. *'''Antiscreen plates''' - photographic plates containing dyes that reduce the blue sensitivity. Used unfiltered, they can give results similar to those obtained with yellow filtered orthochromatic plates. *'''Apodization''' - lens treatment designed to cut down diffraction fringes that appear around the images bright points of light. *'''Aquatint''' - etching technique allowing control of tonal areas to produce almost unlimited gradations from pale gray to black. Because of this it has also been used in photography as an alternative term for gum bichromate process. *'''Argentotype''' - Mid-19th century silver print process, on which the kallitype and sepia paper processes are based. *'''Aristotype''' - early commercial print type made on collodion-chloride or gelatin-chloride paper. *'''Azo dyes''' - compounds forming colors of great strength and purity. Used in camera filters and integral tripack dye-bleach materials. a5cb819f9093313bb4b2d3fd43ab62ac8397cf3c 0 157 162 161 2013-05-12T02:51:21Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki '''A Beginners Approach to DCG Holography''' By: [[John Pecora]] (Note: as this is an original article please do not edit it unless you are John. Please use the discussion page to comment on this work.) ==Abstract== As the availability of green lasers becomes cheaper and more widespread, so does the potential for one to make their own Dichromated Gelatin (DCG) film and holograms. The purpose of this paper is to provide a basic step-by-step set of procedures such that the beginner may have success in producing their own DCG film and making simple DCG Holograms. There are many variables in the fabrication and processing which alter the aesthetics of a DCG hologram, most of which will be beyond the scope of this paper. And the basics here will not guarantee a professional quality hologram but will lead the reader down one correct path to successfully make DCG film and DCG holograms. It will be up the reader to take the next steps to perfect the quality and repeatability of the DCG hologram process. ==Introduction== DCG emulsion is made from a simple solution of Ammonium (or Potassium) Dichromate, Raw Gelatin and Water. Exposure to the DCG emulsion is done in the Green or Blue with higher sensitivity to the shorter wavelengths. Processing is simply a soak in Standard Photographic Fixer followed by a soak in water followed by a dehydrating process in one or more alcohol concentration baths. As a DCG hologram is susceptible to image loss when exposed to moisture, the DCG hologram will be sealed. There is a multitude of ways to perform each of these functions and the ones presented here have been tried and prove to work but may not be the best or suit a particular application for the DCG hologram. ALSO, IT IS VERY IMPORTANT TO INSURE SAFETY AT EACH STEP OF THE PROCESS USING GOOD CHEMICAL SAFETY PRACTICES, KNOWLEDGE OF THE CHEMICALS AND EQUIPMENT BEING USED, PROPER DISPOSAL OF CHEMICALS AND COMMON SENSE. It is not within the scope of this paper to point out safety hazards and it is the responsibility of the reader to research each and every potential safety hazard. I also suggest reading the entire paper first to familiarize your self with the procedures and note any materials and supplies you may need. ==Glass Preparation== Cleaning the glass properly is important. If the glass is not cleaned properly the emulsion can lift off the glass in spots or completely during processing. Also, if there are any dust particles, the emulsion tends to have different properties at that area and a circular ring of deformation of the hologram will be seen around that area. Soak the glass in a 3% concentration of Hydrochloric Acid overnight. This can be bought as Muriatic Acid from most home improvement centers. You could also use a 25% concentration of household bleach. This procedure also works for recycling glass from previously coated plates but I found the bleach takes longer. After soaking, using rubber gloves, scrub the plates with a plastic wool scrubby used for cleaning Teflon pans. Steel wool may scratch the glass. After scrubbing rinse the glass thoroughly under running water and place in a tray of running water. Then repeat the rinse process while rubbing again with the plastic wool. After the final rinse, lean the plates against the wall on a paper towel. Before the plates dry completely use a paper towel to dry off one plate at a time and continue to turn the paper towel until the plate is dry. You will hear and feel the difference between a damp plate and a dry one. Repeat for the other side of glass. Do not touch the plate with your skin or oils will be left behind which can also cause the emulsion not to stick to the glass. ==DCG Emulsion Fabrication== DCG emulsion is comprised of an amount of Distilled Water, Dry Gelatin and Ammonium (or Potassium) Dichromate. A good starting formula is 100:12:3 for the procedures described here. Take the water and place it in a heat resistant glass or plastic container. Place this on a Magnetic Heater/Stirrer or in a double boiler. Add the Gelatin to the water while it is cool and allow it to mix for a couple of minutes. If you are not using a Heater/stirrer the stirring should be done by hand. Bring the temperature up slowly to a maximum of 120 F and a minimum of 110F. Once the solution reaches the 110 F temperature continue mixing until the gelatin mixture is completely dissolved. With the Heater/stirrer allow the solution to be well mixed the entire time but not so fast as to cause excessive bubbles or foam. By hand, mix well for one minute every 5 minutes (this get laborious by hand). Mixing too long is better then under mixing and I suggest 45 minutes after the minimum temperature is reached for a more aesthetic hologram. But again shorter times may be used as long as the gelatin is dissolved. It will look very clear and not cloudy when dissolved with no suspended particles. FROM THIS POINT ON A SAFELIGHT MUST BE USED UNTIL AFTER THE WATER BATH IN PROCESSING. A good safelight to use is a standard yellow incandescent bug light. Now add the Dichromate. Allow this to mix until it is all dissolved (about 15 minutes) within the same temperature range. When this is completed, filter the mixture through a paper coffee filter into a clean container. A funnel or similar can be used to hold the coffee filter paper. It is best to allow the narrow end of the funnel to touch or be very close to the bottom of the final pouring container such that dripping from the funnel end does not produce bubbles. The container can be a beaker or other similar container that can easily be poured from but at the same time can be put back on the Heater/stirrer or back in the double boiler to maintain the previous temperature range. If the emulsion is cooler during coating the final emulsion thickness will be thicker. Take a Q-tip and pop or remove any small bubbles that may be on the emulsion. The emulsion is now ready to coat. The emulsion can be stored at this time in a refrigerator but should be sealed, labeled and not allowed to be exposed to light. ==Plate Coating== The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70F.) Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45 degree angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. Take the plate and immediately place it on a table and spin it as 78 RPM’s. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. I prefer the spin method. If you run out of emulsion in the pouring container, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. ==Exposing the Plate== The plate is best after 4 hours old and can be up to a week(s) old. I have found the brightest holograms are between the 4 and 12 hour age. It seems when plates are older they are harder to get broadband replay and/or replay into shorter wavelengths and lose some sensitivity. The simplest recoding geometry is a Single Beam Reflection in which the object is lying down on its back and the plate is laid right on top of the object. Make sure the object and plate do not wobble. Place the emulsion facing the object. As DCG is quite relaxing in the energy requirements I suggest doing test exposures with the times being doubled thus covering the largest range of times in the least amount or test exposures. Once the time range is found with your laser it will be easy to reproduce. An example is 10 seconds, 20 seconds, 40 seconds, 80 seconds, and 160 seconds. After exposure allow the plate to set in complete darkness for 2 to 5 minutes before processing. ==Processing the Plate== All temperatures can be at room temperature (70F). Take the plate and put it in Kodak Rapid Fixer with hardener. The Fixer should be mixed as per the instructions for the most dilute mixture (paper 1:7). Gently rock the tray until all yellow is gone then an additional 15 seconds. This should take anywhere from ½ minute to 2 minutes. I use a white tray to observe the yellow more easily. Once this is completed, place the plate in running water for 5 minutes ( a tray of water can be used if running water is not available). I now turn on a quartz halogen light that shines on the spot where I will lean the hologram to blow it dry. Then take the plate and place it in 35% alcohol for 15 seconds. Then 70% alcohol for 15 seconds, then 91% alcohol for 15 seconds then finally 100% alcohol until diffraction is visible (anywhere from 15 seconds to two minutes or longer). As soon as diffraction (colors) is seen allow another 15 seconds in that bath. Then take the plate out and lean it against the wall in the overhead light. With practice you will find which angle the diffraction is seen in the light and which way that relates to the visibility of the hologram when blow drying it. As soon as you lean the plate against the wall begin blow drying it with a hair dryer set on its hottest and strongest settings. Blow dry very close to the plate. Start at the center and in a circular motion move to the outside of the plate and repeat often. If the plate is leaning the right way the diffraction and image should start to get really bright. Continue drying until hologram in completely dry. You cannot over dry but you can under dry. This usually takes me 5 minutes minimum. ==Sealing the Hologram== If the hologram is acceptable in quality and brightness to your liking, it must be sealed against moisture. After it is completely dry, use a razor to scrap off ¼ inch of emulsion from around all 4 edges. Three edges will be easy if you maintained ¼ inch when pouring the coating. The bottom wiped edge from coating will probably need the most attention. Now have another cleaned piece of glass ready the same size as the hologram. Mix up some 5 minute 2-part epoxy. I use a Q-Tip with the swab cut off. Now take the Q-Tip and use it to lay down a bead of epoxy around the entire cleaned edge on the emulsion side of the hologram. Take the clear cleaned piece of glass and place it over the hologram. You should see the epoxy sandwiched between the glass plates at the edge where the emulsion was scraped. Look closely and make sure there are not voids where the epoxy did not get sandwiched. Let the plates dry horizontally and check often to make sure the top plate does not slide and move into a different location. After about 15 minutes the hologram can be displayed as liked. d3777ac456286777b128f7da3cf645424ae416dd 0 158 164 163 2013-05-12T02:51:21Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki #redirect [[A Beginners Approach to DCG]] 00326dff2d8e6c55534a1327009e21165d697841 0 159 166 165 2013-05-12T02:51:21Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==Here's my two cents:== From Joe Farina: Mix dichromate, gelatin, and water using some kind of double-boiler method, and keep it under 60C. Coat plates using whatever method you prefer. Let them dry under a gentle air flow for 4 hours. Store your plates in the refrigerator (use lock & lock or some other kind of airtight container). Make as many plates as possible to enable lots of tests. Do not desiccate or do anything else to them. (By the way, use Knox gelatin from the grocery store.) Now, do tests at your lesiure. Just take your container out of the fridge, let it get up to room temperature, and take a plate out (or you can immediately take it out if you hit the surface of the gelatin hard with warm air from a hairdryer to prevent excess condensation). Expose Denisyuk style with 100mW at 532. (I would say 2.5" X 2.5" plates would be good.) Let them set in the dark for 5 minutes after exposure. Rinse under cold tap water for a minute until the yellowness goes away. Soak in room-temperature water for a minute. Soak in 91% for a minute with agitation (room-temperature). Soak in 99% for three minutes with agitation (room-temperature). Then dry with hot air. If there is milkiness, you will need to harden the gelatin more after the dark reaction. You can user fixer or a 100W light bulb 6 inches away (for varying time periods) to do this. I prefer the light bulb method. See how your plates age, and how they perform over time. Change variables to see different results (well, I don't need to tell you this, since you probably know better than I do about trial-and-error work in holography). Just use the same principles you use to get such good silver halide holograms. One last word: don't try to pre-plan things too much. Just use the simplest DCG technique possible (it is really very simple if you have blue or green light). Don't make it any more complex than it has to be. End of lecture. * With a C315M (532nm) at 100mw start with a 1 to 3 minute exposure and adjust by factors of two to find the right exposure range. ie. 45 seconds, 90 seconds, 180 seconds. dd7709ca9e3fac825651a47da027a4535eec0201 0 160 168 167 2013-05-12T02:51:22Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki *BS - Beam Splitter *DE - Difraction Efficiency *DMD - Digital Micro-Mirror Device *EASLM - Electrically Addressed Spatial Light Modulation *H1 - A first generation hologram *H2 - A hologram of a hologram (copy) *H3 etc. - Sucessive generations of holograms *HOE - Holographic Optical Element *LASER - Light Amplification by Stimulated Emission of Radiation *l - liters *''l'' - length *LCD - Liquid Crystal Display *m - meters *''m'' - mass *M1, M2, M3 ect. - Mirror 1, Mirror 2, Mirror 3, etc. *mJ/cm^2 - milliJoules per centimeter squared *RH - Relative Humidity *SBR - Single Beam Reflection *SBT - Single Beam Transmission *SF - Spatial Filter *SI - International System of Units *SLM - Spatial Light Modulator *TEA *uJ/cm^2 - microJoules per centimeter squared *" - Inch = 25.4 mm *' - Foot = 12 inches Also see the [[Holography Glossary]]. ------------------------------------------------------------------------------ '''From Sergio on the Forum''' Some post recommendations internationally acept: SI writing style * Symbols do not have an appended period/full stop (.) unless at the end of a sentence. * Symbols are written in upright (Roman) type (m for metres, l for litres), so as to differentiate from the italic type used for variables (m for mass, l for length). By consensus of international standards bodies, this rule is applied independent of the font used for surrounding text.[10] * Symbols for units are written in lower case, except for symbols derived from the name of a person. For example, the unit of pressure is named after Blaise Pascal, so its symbol is written "Pa" whereas the unit itself is written "pascal". All symbols of prefixes larger than 103 (kilo) are also uppercase. o The one exception is the litre, whose original symbol "l" is unsuitably similar to the numeral "1" or the uppercase letter "i" (depending on the typeface used), at least in many English-speaking countries. The American National Institute of Standards and Technology recommends that "L" be used instead, a usage which is common in the US, Canada, Australia (but not elsewhere). This has been accepted as an alternative by the CGPM since 1979. The cursive ℓ is occasionally seen, especially in Japan and Greece, but this is not currently recommended by any standards body. For more information, see Litre. * The SI rule is that symbols of units are not pluralised, for example "25 kg" (not "25 kgs").[10] o The American National Institute of Standards and Technology has defined guidelines for American users of the SI.[11][12]These guidelines give guidance on pluralizing unit names: the plural is formed by using normal English grammar rules, for example, "henries" is the plural of "henry". The units lux, hertz, and siemens are exceptions from this rule: they remain the same in singular and plural. Note that this rule only applies to the full names of units, not to their symbols. * A space separates the number and the symbol, e.g. "2.21 kg", "7.3×102 m2", "22 K".[13][14] Exceptions are the symbols for plane angular degrees, minutes and seconds (°, ′ and ″), which are placed immediately after the number with no intervening space. * Spaces may be used as a thousands separator (1 000 000) in contrast to commas or periods (1,000,000 or 1.000.000) in order to reduce confusion resulting from the variation between these forms in different countries. In print, the space used for this purpose is typically narrower than that between words (commonly a thin space). * Any line break inside a number, inside a compound unit or between number and unit should be avoided, but if necessary the latter option should be used. * The 10th resolution of CGPM in 2003 declared that "the symbol for the decimal marker shall be either the point on the line or the comma on the line". In practice, the decimal point is used in English and the comma in most other European languages. * Symbols for derived units formed from multiple units by multiplication are joined with a space or centre dot (·), for example "N m" or "N·m".[15] * Symbols formed by division of two units are joined with a solidus (⁄), or given as a negative exponent. For example, the "metre per second" can be written "m/s", "m s−1", "m·s−1". Only one solidus should be used, i.e. "kg·m−1·s−2" is preferable to "kg/m/s²", and "kg/m·s²" is something else. Many computer users will type the / character provided on computer keyboards, which in turn produces the Unicode character U+002F, which is named solidus but is distinct from the Unicode solidus character, U+2044. * In Chinese, Japanese, and Korean language computing (CJK), some of the commonly used units, prefix-unit combinations, or unit-exponent combinations have been allocated predefined single characters taking up a full square. Unicode includes these in its CJK Compatibility and Letterlike Symbols subranges for back compatibility, without necessarily recommending future usage. * When writing dimensionless quantities, the terms 'ppb' (parts per billion) and 'ppt' (parts per trillion) are recognised as language-dependent terms since the value of billion and trillion can vary from language to language. SI therefore recommends avoiding these terms [1]. However, no alternative is suggested by the International Bureau of Weights and Measures (BIPM). d0e97b39c47c07f1e87a037dbbc69c4f0c89adf4 0 161 170 169 2013-05-12T02:51:22Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki First of all great thanks to Bill Jensen – without his works on SSY1 I wouldn’t catch pulsed laser bug. Thanks Bill  Here is some information about my homebuilt pulsed laser. I named it YAGna (polish girl’s name, if you visit Poland most of our highlander’s daughters will be Jagna ). YAGna uses SSY1 Nd:YAG laser capable of giving 170mJ; 4ns; 1064nm pulses. It wasn’t built for taking portraits – rather for shooting small objects (insects, splashes, falling drops of quicksilver or Ga-In alloy). Right now I’m running SSY1 just above lasing threshold (2*230V*sqrt(2) = 644V at main cap, which gives something like 6,7J of energy). For two reasons – I’m still using original polymer q-switch which is delicate, at this power level both flashlamp and KTP will last forever. And at lower energy levels beam quality is better (I hope there is less unwanted longitudinal modes). At 6,5 J I get up to 38mJ of IR, after conversion and filtering unconverted IR (a filter from a dead VHS camcorder) I have 8-15mJ of 532nm light. YAGna is equipped with Brewster window to increase conversion efficiency. Conversion efficiency is low since KTP is not working near its destruction limit. It is better for the crystal. [[image:SSY1a.jpg]] YAGna standing on her 3 BLACK legs  Tika looking suspiciously at YAGna. Originally there was a rebreather inside the box (used in coal mines). [[image:SSY2.jpg]] Front side of the laser. A diverging lens, piezoelectric lighter on top (for firing flashlamp) and 3 wing-nuts for adjusting the tilt of KTP crystal. The case is sealed with black electrician’s tape (the tape is black, not the electrician ) to prevent the optics from dusting. [[Image:SSY3.jpg]] Inside YAGna. From left to right – KTP kinematic mount (rotation + tilt), pulse forming network, SSY1 laser on its breadboard, voltage doubler (based on 2 microwave oven HV capacitors and 2 HV diodes), 24V power supply (for PFN1s vacuum relay – after depowering the main capacitor is discharged) and an aligning laser (which ceased to work after 20-30 shots – maybe 0,1% of IR coming out from HR was sufficient to destroy the diode after focusing). As you cans see there is still plenty of room inside, so an amplifier stage, additional PFN1 and trigger board will fit. Case dimensions are something like 30x20x10cm. [[Image:SSY4.jpg]] Diverging lens, KTP mount, PFN1 network and SSY1 laser. The lens is slightly off-line to avoid backreflections (or rather because there were some problems with gluing ) [[Image:SSY5.jpg]] KTP mount. The crystal is glued inside brass block with thermoconductive glue. There is a 5mm tungsten iris in front of 5x5x5mm KTP crystal. [[Image:SSY6.jpg]] SSY1 Nd:YAG laser. Attached to a breadboard using magnets. [[Image:SSY7.jpg]] Beam shape after diverging. Photo was take before I mounted the tungsten iris. Since now I was shooting small (up to 4x3cm) test holograms (at 6,5J), but I got a holo showing entire face profile from Bill (taken at 15J). You can see some of my holos at YouTube: *http://youtube.com/watch?v=6U9ebkGEtl4 *http://youtube.com/watch?v=d4XoRhb9SOg *http://youtube.com/watch?v=LhR24W8M_aA Approximate cost of YAGna so far is around $400 (KTP acosted $250). I think minimalist’s version of YAGna (KTP salvaged from a dead DPSS pointer) could cost below $200. What I’d like to improve in YAGna: * add amplifier stage(s) – 2 SSY1s are already waiting to be used. * add spatial filter (1m focal length, 0,5mm DIY tungsten pinhole). * add trigger board and a laser photogate to make holograms of splashes. * divide YAGna in two – laser head and PSU on separate boxes. * make YAGna portable to make holograms outdoors. * whatever else imagination allows  1279f9614b1ae4b20e8500e87f0fff65e4186f33 0 162 172 171 2013-05-12T02:51:22Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Holograms can be made with no mathematics. However, there is a mathematical basis for all of holography. Below we will explore the mathematical basis for holography. *[[Holography Transmission Equations Part I]] by Ed Wesly *[[Holography Transmission Equations Part II]] by Ed Wesly *[[The Calculus of Holography]] bb014b1458ba31d18d2bc5d1320340d2ae41742f 0 164 176 175 2013-05-12T02:51:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Media Artist and innovator, since 1967, in the areas of film and video, avant-garde film, video art, holographic art, and more recently, stereoscopic 3D video, digital graphics - web media and web-based virtual reality. His films have received a number of awards, including a 1988 Los Angeles Film Critics Award, and his media art works are found in a number of international collections and have been exhibited internationally, including a 1997 stereoscopic 3D video showing at the Louvre, a 2002 film-video retrospective at the Electronic Media Arts Festival in Osnabruck, Germany, and a 2004 exhibition of 3D video, film, video at SeNef, Seoul, Korea. He also has an extensive background as a teacher in film production / film studies, is a past publisher of two periodicals on film and holography, and has invented / developed a number of film, video, holographic and 3D imaging techniques. In 2000-01 he was involved as Head of 2D/3D Graphics for the Mission Corporation (Bellevue, WA) in developments of speech-interactive (avatar-based) graphical interfaces for next-generation (post-PC) environments. He continues to create independent works in interactive 3D web graphics and installations. He has an extensive background as film and holographic arts producer, project lead and designer, critic, historian, writer, teacher and cultural activist, with special skills as cinematographer, videographer, holographic systems and installation designer, producer and director of films and videotapes, screen-writer, stereoscopic 3D videographer and editor, internet site designer, Speech-interactive Avatar UI designer and HTML and VRML programmer-creator. He is also a writer of screenplays, prose, and prose-poetry. d57cf989b83945ec045e7db776e1ed28e61daabd 0 165 178 177 2013-05-12T02:51:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:AStephens.jpg]] [http://anait.com/ Anait's Web Site] Anait (Anait Arutunoff Stephens) was born in Berlin, Germany in 1922. On August 21, 1998, Anaït lost her battle against cancer in Santa Barbara, California, USA, in 1998. 1954 Instituto Nacional de Bellas Artes, Mexico, with Orozco Romero. 1958 Mexico City College, Mexico, with Toby Joysmith. 1964 University of California at Los Angeles, USA, with Dewain Valentine. 1971 School of Holography, San Francisco, California, USA, with Lloyd Cross. 1980 Museum of Holography, New York, USA, Artist-in-Residence. Professional Activities Lectures (selected) 1974 Studio lectures, Artist’s studio, Los Angeles, California, USA. 1977 Electro-Optics Seminar, Anaheim Convention Center, Anaheim, California, USA. 1978 Third Conference On Holography, USSR (the only woman and artist in attendance). Museum of Holography, New York, USA. 1980 Santa Barbara Museum of Art, Santa Barbara, California, USA. 1983 Studio lectures, Artist’s studio, New York, USA. 1986 The Royal Photographic Society Holography Group, London, UK. 1990 Chicago Art Institute, Chicago, Illinois, USA. 1991 Durand Art Institute, Lake Forest, Illinois, USA. 1992 Visiting tutor, Royal College of Art, London, UK. PUBLICATIONS Catalogues (selected) 1976 Through the Looking Glass, Museum of Holography, New York, USA. 1977 Theme and Variation, National Academy of Science, Association of Science – Technology Center, Washington, DC, USA. 1978 Alice in the Light World, Isetani Museum, Tokyo, Japan. 1979 ANAIT Retrospective 1966-1979, Museum Of Holography, New York, USA. 1983 Light Dimensions, Octagon, Bath, UK. 1984 Licht-Blicke, Deutsches Filmmuseum, Frankfurt/Main, Germany. 1987 Light Dreams, Kalamazoo Art Institute, Michigan, USA. 1991 Fiat Lux! Holografia, Asturias, Spain. 1991 Fourth International Exhibiton of Display Holography, Durand Art Institute, Lake Forest, Illinois, USA. Articles/interviews 1973 Blasco-Ibanez, “Down to the Sea in Sculpture”, Los Angeles Herald-Examiner Sunday Magazine, California Living. 1974 Melinda Wortz, “Los Angeles: Anait at Gallery 707”, Arts Magazine. 1978 Lincoln F. Johnson, “Defining, Evaluating Holography”, The Baltimore Sun. Anait, “My Art in the Domain of Reflection Holography” Leonardo Journal, Vol. 11 pp. 306-7. “A Letter to Leonardo”, Leonardo Journal, Vol. 11, pp. 351. 1979 William Wilson, Review, A-B Gallery, Los Angeles Times. 1980 James Wood, “Painterly Holography”, Artweek. 1981 Ricky Horton, “Anait: Holography as Art”, New York Arts Journal. 1987 Joan Crowder, Santa Barbara, News Press. OTHER INFORMATION 1972 Opened “Gallery 707”, Los Angeles. First gallery for women artists in LA. 1976 First solo art exhibit in the world in reflection holography: “Theme and Variation”. 1986 Listed in “Allgemeines Künstlerlexikon” (International Art Encyclopedia). 4b21ee688fe70223afe5dcd06cf39b0da24bfc6a 0 166 180 179 2013-05-12T02:51:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki The bio below was shamelessly pulled from Andres' home page and could use further editing. I have been involved in holography for quite some time. It started back in 1988 when I was in high school and needed to do some experiments for my school science fair week. At the time, all I had was a small 0.5mW HeNe from Metrologic that my grandfather bought for me after a very intense negation with him :), a limited supply of Agfa Holographic plates and one of the best resources of the time for the amateur holographer, the famous Holography Handbook by Fred Unterseher, Jeannene Hansen and Bob Schlesinger. The setup consisted of a sand box (as described in the handbook) resting on top of 4 inner tubes and 4 cinder blocks, some mirrors, lenses, Kodak D19 developer and a few other chemicals for development and bleaching (can’t remember the names). The process was very frustrating at the beginning. After using almost half the box of holographic plates, no hologram was obtained. You can imagine how wonderful it was when I was able to produce my first hologram. It’s a day I will never forget… I was only able to work with holography for a very limited period at that time and I was not able to do any holography work for 13 years. That all changed in 2003 when I met Michael Harrison. Susan, his wife, works with me and she used to bring Michael’s holograms to the office all the time. It didn’t take long for me to notice that and after talking with her decided to meet him. Well, suffice it to say, I got hooked instantly. Michael’s setup at his house is impressive and he was more that willing to help me get started again. This time though, things were a lot easier. First, I have another holographer that lives 5 minutes from my house, the internet, the holography forum for discussing anything holograhic with profesional and amateur holographers all over the world and last but not least, there is e-bay, the best source for equipment, lasers, optics, books, and anything relating to holography. My current setup is a lot more complex that my first one, it consists of an isolation table top built using a light weight material called Hexcel (a honeycomb material) sandwiched between three layers of steel sitting on top of inner tubes. A pair of 8” parabolic mirrors, spatial filter, magnetic bases to hold components, tons of lenses and mirrors and of course a laser (15mW HeNe). http://www.ghisays.net/default.php 00929dcbc49c1862c22afc4f93b7af016ec5560d 0 167 182 181 2013-05-12T02:51:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [http://www.apepper.com/ Andrew's Web Site] Andrew Pepper studied Fine Art in the UK, where he began working with projected light and 3-D light installations. During this period he saw his first hologram in Paris, at an exhibition organised by Jody Burns and Posy Jackson, at the American Cultural Centre, in the City. He thought this would be the ideal medium to use to document his installations in 3-D. On conclusion of his Fine Art course, he spent 2 years at the Museum of Holography, in New York, as a Fulbright Scholar, and it was there that he learned how to make holograms at new York Holographic Labs. It was some time before he felt comfortable using the medium - wanting to find an alternative to the amazing 3-D effect which had originally attracted him to the medium. When he returned to the UK in 1981 he began lecturing and writing on creative holography and starting to produce his own work, which has now been exhibited in solo and group shows world-wide. He also completed a PhD in Fine Art Holography, the first of its type to be awarded by the Fine Art Department of the University of Reading. During 1988 Pepper was awarded a Lionel Robbins Memorial Scholarship which allowed him to continue his PhD research and carry out extensive exploration in a specially built holography studio at Reading University. In 1991 he moved to Cologne to take up a 5 year post with the newly established Academy of Media Arts, which as part of its studio activities was offering Holography under the direction of German Artist, Professor Dieter Jung. During this time in Germany he was able to realise a project he had been working on for several years earlier and founded the Creative Holography Index, The International Catalogue for Holography, which provided a very high quality collection of material about artists working in the medium, as well as commissioning several leading writers to give their views on the development of the field. While at the Academy he was introduced to the Internet and world wide web and eventually began to ‘translate’ the paper publication into a digital one, making it accessible to a much wider audience. He has remained interested in this idea of digital publishing and delivered several papers on the subject at international conferences. 1996 saw him move back to the UK to organise and chair Art in Holography2, a major international symposium which attracted speakers and delegates from all over the world and concentrated entirely on the art of the medium. From 1999 - 2004 he was director of the Shearwater Foundation Holography program, established by Posy Jackson in 1987. Each year it provided 100,000 US Dollars to support and encourage creative holography, as well as honouring several artists with the annual Holography Award, given to outstanding practitioners in recognition of their major contribution to the field. Pepper is a visiting lecturer at the Nottingham Trent University, School of Art and Design, a81150217a4ebfab9398686a109b60c4c291408e 0 168 184 183 2013-05-12T02:51:24Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Sneaky Fish]] by Jeff Blyth dca874f2dad612d5707d3961b50d354bbb8721ba 0 169 186 185 2013-05-12T02:51:24Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki By: John Pecorra Well, there has been some talk about tables and plateholders so I thought I might post my plateholder design. It is original and I like it better then any plateholder I have ever used or seen. It allows from a 4" to a 20" format. It is quick and easy to load, even in the dark. It is very stable. I tried to put notes in the drawing to describe how it works but feel free to question anything. Also feel free to use the design if you want. It is all steel construction. The vertical poles are solid 1 1/2" rods. The angle iron on the top has holes cut out for the poles but the holes are slightly larger. There is no need to have the holes and rods within close tollerances. The top angle iron simply rests on the plate via the 2 sets of 2 screws as described. Then the thumbscrew is turned to place a slight bit of pressure from the angle iron to the pole to take the "ting' out but no stressing is involved as the large holes in the angle iron allow the angle iron to float freely, tilting to and away from the pole with the turn of the screw. The design of the top shades the very top part of the plate so nothing else is needed to keep the light from entering the edge of the plate. Another nice feature is there is room to squeeze light very close to the plate on the inside or outside of the pole depending on acutal film plate size. [[Image:AngleIronFilmHolder.jpg]] fd43596e97af92e42c70bb3ebc8212d2107107ea 0 170 188 187 2013-05-12T02:51:24Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[http://www.anamarianicholson.com/ Anna's Web Site]] f6bd52d29c8f2d410b070d90cd8b8218163113b6 0 171 190 189 2013-05-12T02:51:24Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==Holowiki Mirror== [http://www.holowiki.org/archive/holographyforum.tgz Holography Forum Archive] [http://www.holowiki.org/archive/text_only_holographyforum.tgz Holography Forum Archive text only] [http://www.holowiki.org/archive/holoforum.tgz holoforum Archive] [http://www.holowiki.org/archive/text_only_holoforum.tgz holoforum Archive text only] ==holoforum.org Archive== [http://holoforum.org/data/archives/index.html Archive directory at holoforum] 87750c01cd44ffb98699ec02365dc5d555282a66 0 172 192 191 2013-05-12T02:51:25Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==What is Art?== This is the age old question artists and critics have bantered around since before writing. Leo Tolstoy wrote an essay about it called [[What is Art?]]. "A large part of the beauty of a picture arises from the struggle which an artist wages with his limited medium." - ''Henri Matisse'' "Art is a man made object that is created to release an emotion from the artist and to invoke an emotion in a viewer." - ''Colin Kaminski'' A very informative treatment can be found in Maragret Benyon's [http://www.holonet.khm.de/benyonarchive/writings/gram.htm Holography as Art] ==The Hologenic Object== ==Composition== ==Lighting a Hologram== ==Fitting a Hologram into Your Decor== 795e43a762410d45d545577d6b75cabaef54a284 0 173 194 193 2013-05-12T02:51:25Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [http://www.lasart.com Lasart] 0bd5063994c88bb56707ba655937ebc3c2b024fc 0 174 196 195 2013-05-12T02:51:25Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Ballistic photography''' - photography of weapons, ammunition and projectiles usually used for analysis. *'''Baryta''' - coating of barium sulfate applied as the foundation to fiber based printing papers. *'''Base-relief''' - photographic image effect usually produced by printing from a negative and a positive sandwiched together in the enlarger, slightly out of register. *'''Belitski's reducer''' - solution used as a chemical reducer for negatives. It consists of ferric potassium citrate or oxalate in an acid fixing solution. *'''Bichromate''' - refers to potassium bichromate or potassium dichromate, used for bleaching and as a sensitizer for gelatin. *'''Bitumen''' - hydro-carbon which hardens by the action of light. It was used by Joseph Nicephore Niepce to produce the worlds first photograph in the early 19th century. *'''Black silver''' - finely divided metallic silver formed from silver halides by exposure and development. *'''Bleach''' - chemical bath capable of rehalogenizing black metallic silver. *'''Bleaching''' - stage in most toning, reducing and color processing systems. *'''Bleach-out''' - method of producing line drawings from photographic images. The photographic is processed in the normal way, its outlines sketched, and the black metallic silver image is then bleached away to leave a drawn outline. *'''Blocked up''' - a portion of an overexposed and/or overdeveloped negative so dense with silver halides that texture and detail in the subject are unclear. *'''Blocking out''' - method of painting selected areas of a negative with an opaque liquid on the non-emulsion side. Since light is unable to penetrate these areas they appear white on the final print. *'''Borax''' - mild alkali used in fine grain developing solutions to speed up the action of the solution. *'''Boric acid''' - compound used in certain fixers to prolong shier hardening life. *'''Brightfield''' - method of illumination used in photomicrography which will show a specimen against a white or light background. *'''Brilliance''' - intensity of light reflected from a surface. It is sometimes an alternative term for luminosity. *'''Brometching''' - obsolete, special method of producing a bromide print. The result acquired the texture of its support and appeared similar to an etching. *'''Bromide paper''' - most common type of photographic printing paper. It is coated with an emulsion of silver bromide to reproduce black & white images. *'''Bromoil process''' - old printing process invented in 1907, consisting of three stages. First, an enlargement is made on bromide paper and processed. Second, the silver image is removed in a bleacher which also modifies the gelatin so it will accept lithographic ink. Third, while still damp the gelatin is inked up by hand to create the image. *'''Brush development''' - method of development in which developer is applied to the material with a brush or similar instrument. *'''Buffer''' - chemical substance used to maintain the alkalinity of a developing solution, particularly in the presence of bromine which is produced during development. *'''Butterfly lighting''' - lighting in which the main source of light is -placed high and directly in front of the subject. 68bb4c1b7d60cf1cff2941ba68af55788a19a94f 0 175 198 197 2013-05-12T02:51:25Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==BBO== ===Physical Properties=== *Crystal Structure trigonal, space group R3c *Cell Parameters a = b = 12.532Ä, c = 12.717Ä, Z = 6 *Melting Point 1095 +/-5°C *Transition Temperature 925 +/-5°C *Optical Homogeneity Dn ≈10-6/cm *Hardness 4.5 Mohs *Density 3.85 g/cm3 *Absorption Coefficient < 0.1%/cm (at 1064 nm) *Hygroscopic Susceptibility low *Resistivity > 1011 ohm-cm *Relative Dielectric Constant eT11/e0: 6.7, eT33/e0: 8.1 *Tan d, < 0.001 *Thermal Expansion Coefficients(in the range of 25°C- 900°C) a, 4 x 10-6/K c, 36 x 10-6/K *Thermal Conductivity ^c, 1.2 W/m/K; ||c, 1.6 W/m/K ===Chemical Properties=== *Phase-matchable SHG range 189-1750nm *NLO coefficients d11 = 5.8 x d36(KDP) *d11 = 0.05 x d11, d22< 0.05 x d11 *Electro-Optic Coefficients g11 = 2.7 pm/V, g22, g31< 0.1 g11 *Half-Wave Voltage 48 KV (at 1064 nm) *Damage Threshold 5 GW/cm2 (10 ns) **at 1.064 mm 10 GW/cm2 (1.3 ns)1 GW/cm2 (10 ns); **at 0.532 mm 7 GW/cm2 (250 ps) *Transparency Range 189 - 3500 nm *Refractive Indices **at 1.0642 mm ne = 1.5425, no = 1.6551 **at 0.5321 mm ne = 1.5555, no = 1.6749 **at 0.2660 mm ne = 1.6146, no = 1.7571 *Therm-Optic Coefficients **dno/dT = - 9.3 x 10-6/°C **dne/dT = -16.6 x 10-6/°C c9268d428f1472c38e7f4994d246a877debc9a74 0 176 200 199 2013-05-12T02:51:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ===Blocking Un-Wanted Beams and Stray Light=== Stray light becomes an ever more complicated problem as the setups contain more optics. Blocking unwanted light is a requirement of making good holograms. There are many kinds of unwanted light. ====Stray Light from Optics==== Stray light from optics comes in many forms. Painting the edges of lenses with black paint is a good start at taking care of un-wanted light. The best way to stop unwanted light is to look through the plate holder and place a black card in the way of any light getting to the plate that is not from the main beams. There are special papers available but black poster board will work in a pinch. It is important to pay special attention to the collimation mirror. ====Back-Reflections Re-Entering the Laser==== Back-reflections into a laser can be a problem, as the reflecting surface can form together with the laser cavity mirrors an unstable resonator configuration. This can lead to a chaotically fluctuating laser output with many extra unwanted [[Equipment#Longitudinal_Modes_and_Coherence_Length|longitudinal modes]] und intermittend [[Equipment#mode_jumps|mode jumps]], which can easily ruin a hologram. Particularly prone to generate such effects are [[Equipment#Spatial_Filters|spatial filters]], even more so if they use metallic and not blackened pinholes. Especially [[Types_of_Lasers#Diode_Lasersdiodes|laser diodes]] are very sensitive to even minute back reflection. The least expensive solution is to slightly mis-allign all lenses and other reflecting surfaces so their backscatter misses the laser. A more expensive solution is to pass the light through a polarizing cube beam splitter followed by a [[Equipment#Wave_Plates|1/4 wave plate]]. Any light that is reflected back towards the laser will then be deflected 90 degrees off the polarizing cube beam splitter and so won't enter the laser any more. However, this involves [[Equipment#Polarization|circularly polarized]] light and this is often not desirable in holographic applications. The most expensive solution to avoid back reflections is to use a [[Equipment#Faraday_Isolator|Faraday Isolator]]. ====Beams that Represent a Safety Hazard==== Building your optical bench either above or below eye level is the best way to keep the beam safe. Also building side above the laser plane can add a level of safety. Having a laser with adjustable power allows you to lower the poser for alignment and raise the power for exposures is also possible. For very high power lasers that have no adjustable power, using a variable beam splitter to a beam dump can be used. For pulsed lasers a alignment laser can be aimed to be co-incident with the pulsed beam for alignment. If this laser is chosen as a color the film is not sensitive to, it can also be used as a safe light for loading film. ====Beams Dumps==== A beam dump allows one to dispose of the beam without any back reflections and without having it go somewhere that might fog the film. A beam dump consists of a black box with a small opening. Inside the box is a cone that diffuses the light to the sides. When designing your own make sure that the power density on the face of the cone (laser power/area) does not exceed the threshold of damage of the material of the cone. A different beam dump can be made from a glass shade 12 welding filter cut it in half lengthwise. Bounce the beam into the middle of the two plates mounted in parallel so it enters at a 45 degree angle. At each point the glass absorbs much of the light and after only a few bounces the beam is dissipated. 9d727af5a4ed98d01db75f40e4502f4a1c02d093 0 177 202 201 2013-05-12T02:51:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Holography requires that two beams interfere at the plate. This is usually accomplished with a beam splitter. ====Reflective Beamsplitters==== A reflective beam splitter is a partially silvered mirror. It can be made so as to reflect a percentage of the light and transmit the rest. Common beam splitters come in 90/10, 70/30 and 50/50 splits. There are also variable beamsplitters. They consist of a partially silvered mirror that changes density from one place to another. The two types commonly available are linear and circular. The require a stable mount that will allow the ratio to be adjusted without changing the beam direction. Most commercially available beamsplitters are variable neutral density splitters. As such they are made on thin glass. It is common for hobbyists to laminate a piece of glass to the beam splitter to make it thicker. This separates the reflection from the back surface from the reflected beam in order to allow it to be blocked. Any index matching glue can be used. Norland makes a range of UV cured index matching adhesives that are suitable. When placing a reflective beamsplitter make sure to place the reflective side towards the laser. ====Cube Beamsplitters==== Cube beam splitters are used when higher damage thresholds are needed. They are more expensive but there is no problem with the ghost beam. Cube beamsplitters are available in Polarizing and Non-Polarizing varieties. A polarizing cube beamsplitter can be made variable by having 2 1/2 wave plates. One on the input beam and the other on the straight through beam. The input polarization is rotated to get the desired beam ratio and the output polarization is rotated to match the reflected polarization. Cube Beamsplitters are often AR coated. ====Pellicle Beamsplitters==== Pellicle Beam Splitters are not suitable for holography owing to the fact that their thickness (2um) makes it impossible to block the ghost beam from the back surface. 52459d85f79a6d8af9eb3635ae31f6ae2c249da9 0 178 204 203 2013-05-12T02:51:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki The backgrounds of holographers are extremely varied, as can be seen below. Without these people's tireless efforts, holography would have remained a mere laboratory curiosity, rarely to be seen elsewhere. As a result of their work, holographic techniques are more and more frequently used in science, technology, medicine, measurement and art. With the advent of lower cost lasers and recording materials, and also due to the work of the dedicated holographic popularizers among those listed below, there is a small but growing international community of amateur holographers, and it is not uncommon to have hands-on holography courses presented in elementary schools. This project is designed to collect in one place biographical info on all of the people who have made holography possible. Please feel free to post your biographies here. If you know a name but don't know the details, just add the name and we will work on getting a biography. *[[Dave Battin]] *[[Paul D. Barefoot]] *[[Kaveh Bazargan]] *[[Margaret Benyon]] *[[Steve Benton]] *[[Rudie Berkhout]] *[[Hans Bjelkhagen]] *[[Jeff Blyth]] *[[Patrick Boyd]] *[[Pam Brasier]] *[[Harriet Casdin-Silver]] *[[Greg Cherry]] *[[Melissa Crenshaw]] *[[Loyd Cross]] *[[Salvador Dali]] *[[Rebecca Deem]] *[[Frank DeFreitas]] *[[Yuri Denisyuk]] *[[Georges Dyens]] *[[Phil Edelbrock]] *[[Gregg E. Favalora]] *[[Dennis Gabor]] *[[Yves Gentet]] *[[Andres Ghisays]] *[[Nancy J. Gorglione]] *[[Michael Harrison]] *[[Dr. Jeong]] T. J. *[[Frithioff Johansen]] *[[Pearl John]] *[[Colin Kaminski]] *[[John Kaufman]] *[[Roderic Lakes]] *[[Emmett Leith]] *[[Sharon McCormack]] *[[Mike Medora]] *[[Ronnie Michael]] *[[Lon Moore]] *[[Rob Munday]] *[[August Muth]] *[[Ikuo Nakamura]] *[[Anna Maria Nicholson]] *[[Caroline Palmer]] *[[Dinesh Padiyar]] *[[Joy Padiyar]] *[[John Pecora]] *[[Andrew Pepper]] *[[Hart Perry]] *[[Jerry Pethick]] *[[Nicholas Phillips]] *[[Greg Quinn]] *[[Al Razutis]] *[[Jonathan Ross]] *[[Graham Saxby]] *[[Dan Schweitzer]] *[[Mark Segal]] *[[Walter Spierings]] *[[Anait Stephens]] *[[Fred Un'''Bold text'''terseher]] *[[Juris Upatnieks]] *[[Doris Vila]] *[[John Webster]] *[[Edward Wesly]] *[[Mieczyslaw Wolfke]] *[[Sergey Vorobyov]] *[[Sergey Zharkiy]] 754a124146110fa564366d0eed77ce2a48b37667 0 179 206 205 2013-05-12T02:51:27Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki The Blyth Colour Tuning method originated from an observation Jeff posted to the forum and its testing was taken up by a number of people. The results were very promising. The original thread is here: [http://www.holographyforum.org/phpBB2/viewtopic.php?f=2&t=5224 Blyth Colour Tuning Thread] ==Preperation== Stock Solution: *15g Citric Acid *100ml Water Dilute as needed. Soak the hologram to be swelled for 30 minutes. Then dry. Amazingly squeegee technique is not very important here! ==Paulos Test== I cut a 15 x 20 cm film hologram in 4 pieces and applied Jeff's Citric Acid solution method. The result: # (upper left): untreated (514 nm) # (upper right) 11.75 % Citric Acid (=15% x 0.75) # (down left) 7.5 % Citric Acid (=15% x 0.5) # (down right) 15 % Citric Acid [[Image:citric.jpg]] The photo is not the best one (the hologram is free of any noise), but the effect of the various concentrations is obvious. In comparison to sorbitol-treated holograms, the overall quality is better. * Exposure at 514 nm * Holographic film: Finegrained HF-53 from ORWO * This emulsion is much harder than Slavich material. ==Theory== From Jeff Blyth I have been doing a bit more on this since I have receiving an appreciative email from Rob Taylor (Forth Dimension Holographics) about the newly found virtues of the citric acid post swell system.. In it he mentions how forgiving it is to the squeegeeing. technique. I have noticed this too and have just been wiping off the excess citric acid solution casually with tissues and have not seen smeary streaks of darker red which would have occurred with sorbitol solution. Now this convenient fact indicates something about what is happening down at the molecular level. Also I just might possibly have discovered something of interest for DCGers to investigate as a means of changing those finished too-blue colored hologram into red ones –a trick which I think John Pecora has discussed more than once on this Forum over recent years. However with only 2 days of observation I am being rather optimistic to think I have a long term answer to that old perennial DCG problem but I hope that DCG’ers will now try some experiments with old “Bluies and Greenies” as John puts it before just recycling the glass! I will go into a bit of DCG detail at the end of this post. First though I need to hypothesize what is happening at the molecular level to try to understand the observation about squeegeeing technique being less critical with citric acid solution compared to sorbitol or glycerol solution. So as we all know, the building bricks of gelatin are amino acids. In neutral pH conditions these make themselves into internal acid–base structures with the negative – positive ions neutralising each other. The swelling in water is caused by both the positive and negative ions choosing to open themselves up to accommodating lots of water molecules which take on partial induced charges opposite to the ions they surround. So the amino positive ions get surrounded by a cloud of partially negatively charged water molecules and vice versa around the negatively charged acid groups . This allows the original electrostatic attraction between the oppositely charged components of the amino acid to slacken and the components to move apart by a factor of 2 or 3 times their unswollen distance. An accepted way of keeping gelatin based holograms swollen with water has been to try to replace a lot of the water with non- volatile very hydrophilic “polyalcohols” such as glycerol or sorbitol . These alcohols get involved in the cloud of water molecules surrounding the charged amino acid groups. The size of this cloud of water molecules around the oppositely charged amino acids is very imprecise , variable and dynamic, (this description will be important), it instantly can change with temperature and humidity changes so it is difficult to control color changes of gelatin based reflection holograms. (They act as superb humidity change sensors---a fact I am personally gaining from in the development of “Smart” holograms to test for water in aviation fuel.).. Just breathing on them can make a wavelength change of tens of nanometers as we all know. However in the case of a hologram treated with citric acid and then blow dried at room temperature we are left with a swollen gelatin which is different from the case of one swollen with water plus sorbitol or glycerol. In citric acid we have in effect the line of 3 carbons in glycerol now with their alcohol groups (-OH) replaced by carboxylic acid groups (-COOH) except for the central carbon which has the (-COOH) added in place of H leaving one alcohol OH still there (more on this later). These –COOH groups introduce a different effect to cause the swelling of the gelatin. This time the citric acid (-COOH) groups can partially displace the original internal (-COOH) groups from their attraction to the amino groups. These displaced (-COOH) groups are still firmly attached to the gelatin biopolymer of course and are not free to wander off in solution so the rest of the citric acid molecule is forced to be accommodated into the gelatin structure as most of the surrounding water is now evaporated off thus leaving the gelatin in a swollen state when it is left to equilibrate with ambient humidity.--- Fortunately it is a chemically weak arrangement easily completely reversed by plenty of fresh water so that it becomes energetically more favourable for all the ions involved to go back to surrounding themselves with water-molecule clouds again . The upshot of this is that if you are not satisfied with the color of your treated hologram you can go back to square one without any difficulty . I have not found the slightest trace of the effect of citric acid after rewashing in water. --An important feature for any precious holograms whose color you are trying to tweak. In the above model one can sense why the removal of excess surface liquid on a hologram treated with citric acid solution is more forgiving (in the final result) from an unequal treatment with a squeegee blade compared to the same situation with an excess of sorbitol solution. In the case of excess sorbitol that final sheath or cloud of water/sorbitol molecules which I described above as "very imprecise , variable and dynamic", as they surround the amino acid ions they can be far too sensitive to small variations in residual water causing corresponding local variations in reddening of the final replay color as the clouds expand or contract. Whereas in the case of the citric acid, the reddening is caused mainly by a specific alteration of the internal molecular structures of the amino acids and perhaps not much by a variable cloud around the ion.. Now experienced DCGers have long since found that you cannot change the color of a finished too-blue DCG by playing around with sorbitol treatment. Anything that attracts water is anathema to DCG holograms. So the question naturally arises can one somehow do it with this different citric acid mechanism? Well I took a blue green finished DCG , left it in 10% citric acid for 10 mins, (I cut the time down from my previous 30 min recommendation because I noticed the gelatin was starting to come off the glass after 5 mins) I then briefly wiped it with a tissue an plunged it into a stirred beaker of ~100% ipa at room temperature. ( I needed to avoid using ipa/water solution as it was likely to loose citric acid. The acid fortunately seemed to prefer to keep its weak attraction to the gelatin rather than dissolve in ipa. only). The good news is that the resulting hologram after a long cool blow was a deep red hologram instead of a blue green one. But the bad news is that that only 3 hours later it had vanished.. But ……don’t go away yet…………. I tried a variant. …… The problem was of course likely to be too much water attracted in still--the water cloud around ions was probably still there to some extent which caused the air- void fringe structure to be unstable and disappear. So could an improvement be got by using an alternative organic acid without a residual alcohol –OH group still present? So I tried succinic acid instead. This is a non- poisonous but quite strong organic acid (a “natural” product too) with the 2 alcohol groups in ethylene glycol replaced by –COOH groups. I found that it saturated at room temperature at around the 6% level but treating green silver halide holos with it did make useful color shifts to yellow (in the case of BB plates but not in the case of the harder Fuji film,) it was though much less effective at causing the amount of color shift you can get from the same concentration of citric acid. The question is then is this less hydrophilic acid able to keep a color shift in DCG? So far my test sample is still maintaining its green to orange shift after 36 hours but I would not put any money on its permanence. So I am hoping some DCGer will pick the idea up, get in a bit of succinic acid and play around with sealing it up etc. ---it could be an interesting alternative to recycling those “Bluies”. Jeff 1bbe75e63fe26cf167311d6b7396886cb3c5dbd9 0 180 208 207 2013-05-12T02:51:27Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==Must Haves== *Saxby, G., "Practical Holography" Third Edition, IOP, 2003, ISBN 0750309121. Reviews: [http://www.designerinlight.com/holo/graham.htm][http://www.dragonseye.com/blog/archives/17-Practical-Holography-3rd-Edition,-Graham-Saxby.html] *Unterseher, F., Hansen, J., Schlesing, B., "Holography Handbook", Ross Books, 1982, ISBN 0894960164. Reviews: [http://www.dragonseye.com/blog/archives/18-Holography-Handbook,-Unterseher,-et.-al.html] *Bjelkhagen, H., "Silver Halide Recording Materials for Holography", Springer-Verlag. 1996, ISBN 3540565760 *Hariharan, P., "Optical Holography", Cambridge University Press, 1996, ISBN 0521439655 *Keechner, W., "Solid State Laser Engineering", Springer, 1999, ISBN 3540650644 *DeFreitas, F., Rhody, A., Michael, S., "Shoebox Holography", Ross Books, 2000, ISBN 0894960601 ==Other Books== *Saleh, B., Teich, M., "Fundamentals of Photonics", John Wiley and Sons, 1991 *Jung, T. editor, "Holographic Imaging and Materials", Vol. 2043, SPIE, 1994 *Kock, W., "Engineering Applications of Lasers and Holography", Plenum Press, 1969 *Kasper, J., Feller, S., " The Complete Book of Holograms", John Wiley and Sons, 1987 *Cathey, W., "Optical Information Processing and Holography", John Wiley and Sons, 1974 *Brown, R., "Lasers: Tools of Modern Technology", Doubleday, 1968 *Jung, T. editor, "Practical Holography II", SPIE, 1987 *Iovine, J., "Homemade Holograms", Tab Books, 1990 *McGomb, G., "The Laser Cookbook", Tab Books, 1988 *Saxby, G., "Holograms", Focal Press, 1980 *Hecht, J., Teresi, D., " Lasers: Light of a Million Uses", Dover, 1998 *Horn, D., "Laser Experimenters Handbook", Tab Books, 1988 *Kock, W., "Lasers and Holography", Doubleday, 1981 *Ross, J., "3x8+1", Holograms 3-D, 1994 *Bergquist, C., "Laser Design Toolkit", Prompt Publications, 1999 *Smith, H., "Principles of Holography", Wiley, 1969 *Vacca, J., "Holograms and Holography", Charles River Media, 2001. Reviews: [http://www.dragonseye.com/blog/archives/19-Holograms-and-Holography-Vacca.html] *Gorglione, N. editor,"The Archives of Holography", Leonardo Vol. 25 No. 5, Pergamon Press, 1992 ==Holography Marketplace== *Ross, F., Yerkes, E., editors"Holography Marketplace: Second Edition", Ross Books, 1990 *Kluepfel, B., Ross, F., editors, "Holography Marketplace: Third Edition", Ross Books, 1991 *Kluepfel, B., Ross, F., editors, "Holography Marketplace: Fourth Edition", Ross Books, 1993 *Kluepfel, B., Rhody, A., Ross, F., editors, "Holography Marketplace: Fifth Edition", Ross Books, 1995 *Rhody, A., Ross, F., editors, "Holography Marketplace: Sixth Edition", Ross Books, 1997 *Rhody, A., Ross, F., editors, "Holography Marketplace: Seventh Edition", Ross Books, 1998 *Rhody, A., Ross, F., editors, "Holography Marketplace: Eigth Edition", Ross Books, 1999 ==Optics Books== *Popular Optics [[Popular Optics Review]] *Facets of Light [[Facets of Light Review]] *Seeing Light [[Seeing Light Review]] *Light Science [[Light Science Review]] 24deb9fc6bbd4df420e89da52eee5d14ede083e4 0 181 210 209 2013-05-12T02:51:27Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki When Sir David Brewster was studying [[Polarization]] he found that at a certain angle the reflected light was completely polarized. We now call this light s-polarized. The p-polarized light is completely transmitted throught the medium. As holographers we use this method to polarize lasers by inserting a brewster's window into a laser or to minimize the reflections from a piece of glass holding our emulsion. Since out laser is completely polarized we can choose s or p polarization independently from the other. [[Image:BrewstersGraph.jpg]] A graph of reflection vs incedent angle for s-polarized (dashed Line) light and p-polarized (solid line) light. ===Brewster's Law=== [[Image:BrewstersEq.gif]] Brewster's Law calculates the angle of minimum reflection for [[Polarization|p-polarized]] light. n1 and n2 are the [[Refractive Index|refractive indicies]] of the two media. Usually for us that is 1 for air and about 1.5 for glass. So, for air at 1.00029 and glass at 1.5 we get: tan(theta)=1.5/1.00029 theta=56.3deg And then for gelatin 1.36: tan(theta)=1.36/1.00029 theta=53.66deg More information about when to use Brewster's Angle can be found [[Brewster's Discussion|here]]. ===Finding Brewster's Angle=== One way to determine Brewster's Angle is to set up your laser for [[Polarization|p-polarization]] and place a single piece of glass in it. Hit the glass with your spread beam. The glass is going to reflect some of the light hitting it, so place a white card in this reflected light path (in order to view it). If you rotate your glass plate, you will notice that this reflected light becomes brighter and dimmer. Find the spot within the rotation where the reflected light is at it's dimmest on your white card, and you've got it. With a properly-running diode, the reflection will go completely out on the card (100% -- or VERY close to 100% -- transmission through the glass). Also of interest is the angle change when a beam travels between two materials of different indicies of refraction defined by [http://en.wikipedia.org/wiki/Snells_law Snell's Law]. 1926ee1bae862fb0ec0489bff16add66cef2350c 0 182 212 211 2013-05-12T02:51:27Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki More information can be found at [[Brewster's Angle]] and [[Polarization]]: Kaveh Posted: You want to reduce reflections between surfaces, so as not to get woodgrain. So you should make sure your reference beams are p-polarized. In this way, you will always get less reflection than s-polarized light. Now, if you want to be sure you get no reflection, then you should use p, and come in at the Brewster angle. But holography is a compromise, and always having to use Brewster is limiting. So, we can use other angles, knowing that at least we are getting less than we would with s polarization. Look at the graph showing the reflectivity of the two states: [[Image:BrewstersGraph.jpg]] At zero incidence, around 4% of all light is reflected. As we increase the angle of incidence, the reflected portion of the s light, dashed curve, steadily increases. But p decreases first, going to zero at Brewster's angle, and then increases. Now take 45 degrees. With s, you get around, say, 8% of the light reflected. With p, only around 1%. So you have dramatically reduced the unwanted reflection beams, and not used Brewster. Bob Hess posted: I'd like to share a technique I've discovered which prevents "wood grain" fringes, and increases both the brightness and "viewing zone" of image-planed reflection holograms. It's based on the material Polaroid used to make to reduce glare off computer screens, which is a circular polarizer laminated to a linear polarizer (I believe the product number was HNCP-36). I was using p-polarized light in the collimated reconstruction beam for my 30x40cm H1s, and p-polarized light in the collimated reference beam (at approximately Brewster's angle) for the H2. The system was laid out flat on the table, so that all incidence angles were parallel to the table. The problem was that the light comming from anywhere on the H1 that was out of the plane of incidence was no longer p-polarized when it hit the H2 recording plate! This effectively decreased the efficiency of the gratings formed by those rays (the skew rays) and the collimated reference beam. My solution was to use the HNCP-36 as follows: A) the HNCP-36 was cut so that the linear side was parallel to the edges of the piece (as opposed to being at 45 degrees as supplied), B) the HNCP-36 was index-matched to the emulsion side of the recording plate with the linear side toward the emulsion and oriented to pass s-polarized light, C) the reconstruction beam for the H1 was made to be circularly polarized, and D) the reference beam for the H2 was made to be s-polarized. The use of a circularly polarized H1 reconstruction beam meant that the skew rays diffracted by the H1 were also circularly polarized. This light would first encounter the circular polarizer at the recording plate, which would make them linear again. The resulting linearly polarized skew rays would then make fringes of maximum visibility with the linearly polarized reference beam, and this increased the brightness of the H2 when viewed off to the sides. The use of s-polarization at the H2 recording plate provided maximum fringe visibility regardless of the angles of incidence, therefore increasing the overall efficiency of the hologram. "Wood grain" fringes were avoided because: A) the linearly polarized reference beam passes through the linear polarizer, B) it's made to be (let's say right-handed) circular, C) reflects off the polarizer-to-air interface as (in this case left-handed) circular, D) becomes linear again after passing back through the circular polarizer (but now its polarization has been rotated by 90 degrees), and E) is absorbed by the linear polarizer before hitting the emulsion again. The downside of this technique is that it is wasteful of light. The resulting holograms, however, are brighter and stay bright all the way to the edges of the viewing zone. Also, the use of Brewster's angle is not necessary for the H2 reference beam. As Keveh pointed out, a little "wood grain" on the H1 is tolerable and the small amount that results from this technique is generally not noticed in the final image. 80ad18185278dc6302900eb3da163f9a0457f822 0 183 214 213 2013-05-12T02:51:28Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Callier effect''' - contrast effect in photographic printing caused by the scattering of directional light from an enlarger condenser system. The negative highlights are of high density and scatter more light with little or no scattering from negative shadow areas, which are of low density. This gives a print higher contrast than a contact print. *'''Calotype process''' - first negative/positive process, invented by W.H. Fox Talbot in 1839. Paper was coated with silver iodide and a solution of silver nitrate and gallic acid. After exposure the paper was developed in a silver nitrate solution. *'''Camera lucida''' - lens and prism system through which a virtual image was seen, apparently appearing on the surface of the drawing paper. *'''Camera obscura''' - origin of the present day camera. In its simplest form it consisted of a darkened room with a small hole in one wall. Light rays could pass through the hole to transmit on to a screen, and inverted image of the scene outside. It was first mentioned by Aristotle in the 4th Century B.C. and developed through the centuries as an aid to drawing. *'''Canada balsam''' - liquid resin with a refractive index similar to glass. It is used for bonding elements in compound lenses. *'''Candid pictures''' - unposed pictures of people and animals, often taken without the subject's knowledge. These usually appear more natural and relaxed than posed pictures. *'''Carbon process''' - contact printing process, introduced in 1866, using tissue coated with pigmented gelatin. The paper was sensitized in potassium bichromate and contact printed behind a negative in sunlight. *'''Carbon tetrachloride''' - liquid used for removing grease and finger prints from negatives. *'''Carbro process''' - early color print process using an adaptation of the carbon printing process. *'''Carte-de-visite''' - portrait photograph on a mount about the size of a postcard. Introduced in 1854, carte-de-visite became a social craze in many countries during the 1860s. *'''Cast''' - overall bias toward one color in a color photograph. *'''Caustic potash''' - high alkaline used in high contrast developing solutions to promote vigorous development. Highly corrosive and poisonous. *'''Chemical vapor''' - method of exposing negatives in a closed container to a small amount of mercury of sulfur dioxide. After approximately 24 hours the film is developed normally. It produces interesting yet very inconsistent results. *'''Chiaroscuro''' - light and shade effect. The way in which objects can be emphasized by patches of light, or obscured by shadow. *'''Chlorhydroquinone''' - developing agent contained in warm tone developers. *'''Chloride paper''' - printing paper with a silver chloride emulsion. Much less sensitive than bromide paper. Mainly used for contact printing. *'''Chromogenic development''' - process in which the oxidation products of development combine with color couplers to form dyes during processing. *'''Chlorobromide paper''' - photographic paper coated with an emulsion made up of both silver chloride and silver bromide. Used for producing enlargements with a warm, slightly brownish-black image, especially if processed in a warm tone developer.*'''Chronocyclograph''' - photograph used for the analysis of complex cyclic movements. *'''Chlorquinol''' - alternate term for chlorhydroquinone. *'''Chrome alum''' - alternative term for potassium chromium sulfate. *'''CIE standard''' - system of standards adopted by the Commission Internationale de I'Eclairage, allowing accurate descriptions of colors. *'''Clayden effect''' - desensitizing of an emulsion by means of exposure to a strong, brief flash of light. *'''Clearing agent''' - processing solution used to remove stains or to cancel out the effect of chemicals left on the sensitive material left from previous stages in the process. *'''Cliche-verre''' - designs painted on glass in varnish or oil paint, or scratched into the emulsion of a fogged and processed plate using an etching needle. The results are then printed or enlarged on photographic printing paper. *'''Collage''' - composition employing various different materials combined with original artwork attached to some type of backing. *Collodion - soluble gun-cotton, dissolved in a mixture of ether and alcohol. *'''Collodion process''' - also known as "wet collodion" was invented by Frederick Scott Archer in 1851-52. It was a great improvement over the earlier calotype process because because of the large increase in speed gained by exposing the plate while still "wet", but it had the disadvantage of requiring bulky equipment. *'''Color toning''' - system of changing the color of a black and white photograph by converting black metallic silver into a colored compound. *'''Combination printing''' - producing a composite image by printing more than one negative on a single sheet of paper. *'''Compensating positive''' - image on translucent material that can be printed together with the negative of the same image. When combined the result makes printing contrasty negatives easier. *'''Constructivism''' - art movement that begun in Russia c. 1913. Characterized by the use of everyday materials in abstract compositions. *'''Contact screen''' - type of half-tone screen in which the dots consist of slightly unsharp halos. Used to make half-tone images. *'''Contour film''' - special print film producing a equidensity line image from a continuous tone negative or print. *'''Contre-jour''' - backlighting. A photograph taken with the camera pointed directly at the light source. *'''Copper chloride''' - chemical contained in certain bleaches, toners, intensifiers, and reducers. *'''Copper sulfate''' - chemical contained in certain bleaches, toners, intensifiers, and reducers. *'''Copper toning''' - chemical process used for toning monochrome prints. *'''Coving''' - plain curved background which has no edges, corners or folds and gives the impression of infinity. *'''Cubism''' - early twentieth century European art movement characterized by the rendering of forms as simplified planes, lines and geometric shapes. 2d7e2101e3abc4d14ba6c9ba4e4e033ca7f03586 0 185 218 217 2013-05-12T02:51:28Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki If you need to find the change in area between a circle and when it is tranformed into an ellipse by tilting it so that its major axis is increased. When the circular region in 3 space is rotated about one of its diameters, turning it into the new minor axis, the orthogonal radius becomes the major axis, and will be increased by the inverse of either the sine or cosine of the angle, depending on how you measure it. If the circle is just sitting there minding its own business basking in the light waves arriving along its normal, then we say it's moved 0 degrees, so we use cosine, (since cos 0 degrees = 1, otherwise we run into a problem with dividing by sin 0 = 0) because we will be dividing the other diameter's measurement by the cosine of the angle that we have rotated it. Tilting 30 degrees from the normal, the major axis grows by 1/cos 30 degrees or 1/.8660 = 1.155. Then this could be plugged into the area of an ellipse equation. Tilting more to 45 degrees gives a lengthening of the diameter by 1/.7071 or 1.414 times. Notice the areas of the new ellipses compared to the original circle are off by a factor of, you guessed, the cosine of the angle of displacement from the normal! This is why the light meter's reading is attenuated, the area of radiant flux at right angles to the beam is now spread out over a larger area of the transformed ellipse! So there are less photons per unit area! Now does everyone see the wisdom of the detector parallel to the recording material? This can also be used to calculate the area of coverage of your collimation mirror. 5cee890e45ffc680fd23af941c549a693ece58c4 0 186 220 219 2013-05-12T02:51:28Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki '''If you have a poisoning emergency, call 1-800-222-1222 in the US unless the victim has collapsed or is not breathing then call 911.''' ==Basics== *Material Safety Data Sheets (MSDS) can be found very easily on the internet and also come with chemicals when you buy them. Read them. [[Reading a MSDS]]. *Use safety glasses, gloves and an apron when mixing or handling chemicals especially strong acids or bases. *Use dedicated containers for mixing and storing chemicals. Never use household containers that are put back in to normal everyday circulation. *Label and if applicable date every container that has a chemical in it such that anyone else can easily identify it. *Keep a First Aid kit close by and include a sterile eye wash bottle if possible. Better is to have an eye wash station available. *Know how to mix your chemicals and add/mix them in the order described. *Know how to discard your waste chemicals according to your local area. *Never add water to acid. Always add acid to water. With strong acids like Sulfuric acid much heat is created and can boil causing an extreme splashing danger. Dilute strong acids by filling your container with water, place the container in an ice bath and stir while slowly adding the acid. *Never work when feeling fatigued or rushed. ==Safety Apparel== Goggles should be splash proof. A face mask can be worn for dangerous chemicals but must be worn with goggles. Rubber aprons are helpful for strong chemicals. Long rubber gloves will protect your hands and forearms. For fume protection the best solution is to have a well ventelated work area. For extremely strong chemicals it may be necessary to use a respirator. Make sure the cartriges are rated for the fumes you are dealing with. (ie. Carbon for Organic solvents). Most of the chemicals used for making holograms are safe in that you will smell them before you have suffered any damage (the threshold of detection is lower the the threshold of toxicity). For some very dangerous chemicals you can become posioned before you can smell the chemical (The threshold of toxicity is lower than the threshold of detection). For this latter class of chemicals the only solution is to have a source of external air brought into a face mask. Modern paint booths using cyanide kicked paints use a set up like this. It is only mentioned here for people who are using gasses for exotic film treatments. Read the MSDS and choose the safety apparel accordingly. ==List of hazardous chemicals used in holography== *Dichromate - Do not allow Dichromate bleaches to contact your skin. Can cause burns known as chrom holes and if inhaled can burn the nose etc. Also there is a problem with hexavalent chromium, a carcinogen, from Dichromates,and Alodine etc used in metal coating industry getting into the ground water supply. In-situ remediation efforts can change it to trivalent chromium before disposal. One method easy enough for us in holography is to reduce the Cr(VI) to trivalent chromium with hydrogen sulfite in a low ph solution. The dichromate bleach solution generally is around ph 2.4 as given by mix formula. To Remediate the dichromate bleach solution or any chromate/dichromate solution as long as the ph is below 4 and best below 3 is to add sodium metabisulfite (metabisulfite Na2S2O5 is available at photography formulary etc) until the solution is green and then extra to be sure Na2S2O5 in water hydrolysis forms Sodium hydrogen sulfite (bisulfite) NaHSO3. The insoluble relative non-toxic chromium III hydroxide settles out as precipitate, if your willing to wait. So you can then pour off the solution and find a chemical dump etc for the precipitate. If you have a ph meter then by all means add some sodium bisulfate or sulfuric acid before hand to adjust the ph to below 3 to ensure reduction. But in the case of bleach it doesn't require this as the PH is already low. It is possible not all Cr(VI) will be reduced to Cr(III) using the acid reduction with sulfites method. With regard to the low concentration in bleach it worked quite well. Other methods of reducing using Fe(II) or Mn(II) were discussed as a remediation effort. Here is a reference to chromium chemistry including using zinc to reduce Cr(VI) to Cr(III) : [http://www.chemguide.co.uk/inorganic/transition/chromium.html Cromium Reduction] ==Acid Safety== ===Minimum knowledge=== When diluting acid, add the acid to the water. Do NOT add water to the acid. If water is poured into concentrated acid, it may react very quickly causing the acid to bubble or boil. This may cause acid to be sprayed over the working area. If acid is added to water, the reaction is dispersed, and if there is a violent reaction it will spray water or dilute acid. If you spill acid on yourself take off your gear and clothes and rinse off. There is an eye wash by the sink on the opposite side of the room of the acid fume hood. It is on a hose and can be pulled out if you need to rinse off your body and not just your eyes. Do not be shy about removing your clothes or getting water on the floor. It is better that getting an acid burn. ===Required protective clothing=== Goggles with a face mask over the goggles A rubber apron draped over your front The thin nitrile gloves with the heavier longer gloves over them. The gloves are unlikely to dissolve in the acid, but if the gloves are thin they are prone to tearing allowing acid to attack your hands through an unnoticed hole. ===Pouring technique=== After pouring acid it is a good idea to clean off the bottle with wet towel. This prevents an unsuspecting person from burning themselves if they touch the bottle. ===== Disposing of Chemicals ===== === Adding solvents to waste containers === Acetone, Ethanol and Isopropanol are all organic solvents. They are collected together in the plastic storage contain labeled "Non-Halogenated Solvents". The plastic is high density polyethylene: [[http://www.zeusinc.com/chem_HDPE.asp|chemical resistance chart]]. If solvents are halogenated, they get disposed of in the "Halogenated Solvents" disposal in the flammable solvents cabinet. === Disposing of full waste containers === When a waste container is full, send the slip of paper corresponding to its waste label (usually kept on the top of the flammable solvents cabinet) to the address given on the slip. Make sure to add the date. Get a box for the waste bottle (found in the stock room, on the left-hand side under the counter with the inventory computers). Put the waste container in the box, and place the box next to the door in C5. Replace the chemical waste bottle with a new empty bottle, making sure to remove or cross-out its previous label. Fill out one of the waste label slips, leaving the date empty. Place the label on the new waste container and place duplicate slip on top of the flammable solvents cabinet. ===Disposing of acid=== To dispose of acid we neutralize it before pouring it into the waste container. Our containers are made of HDPE and are not rated for fuming nitric acid. They are rated for concentrations of 50% acid or less. But I would still be reluctant to throw the acids away at 50% because when sulphuric acid and nitric acid are mixed they make a strong oxidizing agent and I am not sure how it will react with our container. To neutralize the acid first dilute the acid into a larger volume of water. Then slowly add Sodium Bicarbonate until the mixture stops bubbling. We first dilute the acid to make the rate of reaction more predictable. Also make sure to use a relatively large beaker to prevent the solution from bubbling over. If you used a paper towel throw it away into the acid waste bin under the fume hood. If you feel you got a large amount of acid on the towel you can dunk it in a solution of sodium bicarbonate and water before throwing it away. === Disposing of an empty bottle === Rinse out thoroughly. Remove or cross out label. If the bottle has a barcode, adhere to the Clark Hall inventory guidelines above. For large bottles, we typically place these on the floor next to the gas cyllinders in C5 to be later re-used as waste containers. 7ebdc6c85b0c91e2ab6b047b6cc190f53aa6a83b 0 187 222 221 2013-05-12T02:51:29Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki This is a article stub. ==Using a Pair of Cylindrical Lenses== It is easiest to think of this method as a telescope for one axis only. InputD/OutputD=fl1/fl2 when the lenses are at fl1+fl2 distance apart. For Example: If your laser beam is 2mm wide and 7mm tall and you want to get as close to round as you can. You will align a cylindrical lens so the cylinder is on the wide axis. This will spread the beam. The second lens acts to re-collimate the beam. 2/7=1/3.5 It is easy to obtain cylindrical lenses in 25mm focal length increments from places like [http://www.edmundoptics.com Edmund Industrial Optics]. If you were to choose 25 mm and 75 mm you would be close at 1/3. Placing these lenses at 100mm apart your beam would be re-collimated at 6mm x 7mm which is closer to cylindrical. The laser beam does not care about the orientation of the lenses but the laser does, there are two ways to minimize the reflection back to the laser. One is to place the flat side of the lenses towards the laser and mis-align the lens so the back reflection misses the laser. The other is to place the convex surfaces towards the laser so the back reflection gets spread into a larger area. Which method you choose has to do with how close the lenses are to the laser. ==Using a Pair of Anamorphic Prisms== [[Image:AnamorphicPrism.jpg]] This drawing shows an anamorphic prism pair expanding a single axis of a laser beam. It is also posible to reduce a single axis as well. Note: only one side of each prism needs to be AR coated if the laser beam is P-Polarized as the other is close to [[Brewster's Angle]]. The two dis-advantages of this system is that the beam is displaced and it will only work on one axis if it is not AR coated on all faces. 8b62ba4170440d79a8823bc323e75038c755c1ec 0 188 224 223 2013-05-12T02:51:29Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki From Bastian_S: Dielectric mirrors can be cleaned with acetone and appropriate cleaning tissue, for example this one [http://www.whatman.com/products/?pageID=7.29.142 Whatman 105 Lens Cleaning Tissue] if its just a bit dust you can lay the lens paper on the mirror, put 2-3 drops acetone on the lens paper and pull it away over the surface. It should be dry when the lens paper is completely pulled away. If there is more dirt or fingerprints its the best to fold the paper several times and grip it on one edge where its folded with hemostats. Add some acetone and wipe the mirror ONCE. If you need to wipe again you might fold it again and use a new edge or take a new paper. ====Tips==== *Fingerprints might attack the coating of dielectric mirrors if they stay on it for days/weeks so it might be the best to clean them right after accidently touching them. ====Notes==== *A word of warning here on dielectric mirrors. They typically use fluorides of light elements such as magnesium. These have very low but still significant water solubility, getting a film of water on them can be quite bad so that a say 135nm layer carefully coated to reflect say green could suddenly have patches only say 100nm or so because some of it has got washed away in water so it then it reflects blue instead of green. Evaporating acetone very fast in a cold damp room can produce significant water condensation. A warm hair drier should stop this from happening, I don't have a perfect answer, I am just pointing out something to be aware of. - Jeff 22aa19f528eba1e8b8e5d05c5bd4096116708608 0 189 226 225 2013-05-12T02:51:29Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==ASO fine optics CLEANING SYSTEM== PRECISION COATED OPTICAL Lenses, Corrector Plates and other REFRACTIVE GLASS Used with permission from http://www.arksky.org/asoclean.htm. ===PREFACE=== There are many, many variations of high precision, high reflectivity and high transmission coatings presently offered on the market for both amateur and professional scientists who use OPTICS in their respective lines of study. Smaller glass surfaces with high transmission coatings have always been seemingly easy to clean, since the smaller surface area is not as prone to spotting, sleeking and streaking of the cleaner used. On the other hand, large optical surfaces such as telescope lenses, corrector plates and optical glass "windows" are very difficult to properly clean without some residue being left behind as a result of cleaning. The ARKANSAS SKY OBSERVATORY's new protocol for cleaning optical surfaces includes: 1) judging carefully when cleaning is actually necessary; 2) preparation of the optical surface for proper cleaning; 3) a new solution that combines the attributes of all previous formulae and results in very fast, easy, and streak-free results if used properly; 4) the proper new technique that is highly recommended for cleaning. ===WHEN TO CLEAN OPTICS=== Although we are attempting to obtain the best possible light transmission efficiency from our optics by cleaning them free of deposits, film and debris, lock firmly in your memory that cleaning coated optical surfaces is the single-most damaging action that will be done to them, short of actual physical damage or breakage. No matter how careful, how delicate, nor what cleaning solution is used.....every time cleaned will result in a microscopically-reduced optical performance than before cleaning. Note that the coatings themselves - regardless who makes them and from what they are made - are nothing more than molecule-thick deposits of a very delicate film left on the optical surface from a vacuum process in which air is evacuated and the gases of the coating materials are gently and uniformly distributed across the glass surface after the vacuum container is void of air. This system is devoted to the cleaning of large astronomical refractive optics: lens, corrector, and other optical glass; however the techniques discussed here as well as the new ASO SuperPlus Solution is excellent for the cleaning of eyepieces, eyeglasses, binoculars, camera lenses and all other fine coated optical surface. So....the ground rule here is: CLEAN ONLY WHEN ABSOLUTELY NECESSARY. In most cases, dusting alone will lead to tremendous improvement in performance and overall light transmission. ===PREPARATION TO CLEANING=== DUSTING OPTICAL SURFACES: Large area optical surfaces are frequently plagued by DUST, POLLEN, GRIT, DEBRIS and even human skin and airborne hair. If the surface of the glass is allowed to be exposed at a temperature BELOW THE DEWPOINT, these particulates will stick to the glass and will be stubborn to remove. However, for optimum performance, it is essential to, indeed, remove debris from the optical surface. Your optical glass MUST be dusted when: 1) a flashlight held obliquely against the glass reveals a uniform and fairly thick layer of dust, etc; 2) when POLLEN is on the glass, as leaving pollen will result in "pollen sap" leaving a very difficult-to-remove stain on the surface; 3) ALWAYS prior to cleaning the glass with the solution and technique which follows. Never clean optical glass without gently dusting first! You will find in 3 out of 5 cases that merely dusting off the glass is sufficient to greatly enhance your performance back to optimum and that further physical cleaning is NOT necessary after dust removal. There can be a lot of smudges, stains, flecks and streaks on the glass before it actually begins to degrade your optical performance for all but the most exacting (i.e., high resolution planetary imaging, CCD spectrography and photometry, etc.) demands put upon your telescope. To dust, use a SQUARE-CUT (not a tip-cut) very soft brush that is about 2" (50mm) wide with tapered bristles. I have found several excellent such brushes at Lowe's and Home Depot and other stores where quality painting supplies are sold. Look for the very soft and flexible "touch up" and/or "delicate trim" brushes....most of these are short-handled and have the bristles as an angled radius cut. Make sure that the bristles are incredibly soft; I use the "cheek method" for testing softness: take the brush out of its package and push the tiny ends of the bristles hard against the cheek of your face....if they do not "prick" then they are fine for optical use. Another tip on selecting a brush is the number of bristles....the MORE bristles on brushes just described, usually the softer and better the quality. I start dusting by dusting the METAL SURFACES that surround the optics, ridding them of all debris first; just whisk away. Then start at the top of your glass and gently swipe the surface IN ONE DIRECTION....do NOT move back-and-forth with the brush. Stroke in only one direction. Do NOT rub....merely "pull" the brush across the surface and apply no pressure; let the brush do the work for your. Any particles that do not come off with such brush will be removed in subsequent cleaning with liquid if necessary. The object of your dusting is to essential "move" all the particles to the bottom of the surface you are working on...once there you can brush them off the area and actually assist their removal by blowing gently against the areas being brushed. USING COMPRESSED AIR: DON'T. Period. Dusting is easy, although it may take a little more time, and it is more effective. I have found that compressed air is virtually worthless for attempting to gently remove embedded particles on a glass surface and the chances of the liquid propellants within the can being expelled in liquid droplets against the glass is quite great. The ASO SuperPlus Optical Cleaning Solution - how to mix it yourself! There is NOTHING magic about the new concoction developed over a period of about five weeks here at the Arkansas Sky Observatory. SuperPlus Solution is quite simple, and indeed, there are many familiar components that are being used that have been touted in cleaning solutions before. Nonetheless, after hundreds of elixirs and hours later, this combination - in exactly the proportions given below - results in near-perfect results every time! In striving for the "perfect cleaner" the following criteria were evaluated: 1) Streaking - the solution was required to dry streak free with minimal "dry rubbing" which can damage optical surfaces; 2) Spotting - the solution must dry spot-free with minimal rubbing; 3) Safety - the solution was required in all respects to be totally impervious to the optical coatings and totally safe for all variations of them on the market; 4) Simplicity - it needed to be something that anyone could mix up when needed with over-the-counter inexpensive components; 5) Sure-fire - it must work every time the first time....the less rubbing the better. Experiments on all types of optical glass surfaces were conducted with EVERY cleaner offered by all makers and groups; the following SuperPlus Solution was derived as the "best of all of them" since all had some attributes that were worthy, with some extreme cases omitted. Interestingly although some of the solutions that have been previously offered were deemed very hazardous to the quality of cleaning and even the surfaces themselves, some components used within those solutions did HAVE MERIT and have been incorporated! You will be surprised perhaps at the simplicity of this. ===HERE IS WHAT YOU WILL NEED=== Nearly all components should be available locally; suggested outlets for obtaining these are in parenthesis. 1) distilled water (supermarkets) 2) "pure" isopropyl alcohol (pharmacies, drug stores....may have to be ordered) 3) coffee filters 4) "regular" Windex, the blue kind (supermarket) 5) Kodak PhotoFlo solution (camera and photo houses only) 6) Synthetic Cotton Replacement Pads (some finer pharmacies, medical supply companies....ask your local M.D.!!) 7) two "atomizers" or simple squirt bottles for dispensing liquids (Wal Mart or similar) 8) box of KLEENEX [only!] pure white, no additives tissue (supermarket) 9) quart mixing jars, very clean and sterile (try your cabinets!) 10) sterile eye dropper (drug store). ===NOTES ABOUT THE INGREDIENTS=== What an how you combine these components, as well as HOW you use them will make or break your success in streak-free and perfect cleaning; please make note of the following: Pure Isopropyl Alcohol - NEVER use "regular" isopropyl alcohol. Isopropyl is what you commonly see in stores as "Rubbing Alcohol." However, most on-the-shelf varieties is about 70% or less pure....the remaining 30% is impurities which WILL result in streaking and deposits on your glass. USE ONLY 91% OR HIGHER proof isopropyl....this is found on the same shelf typically, in very large and well-stocked pharmacies. If not, simply ask your pharmacist to order some! Expect to pay about double the price of the "store brand." Windex - Many cleaning formulae suggest Windex, indeed from one of the largest optical houses in the world. However, there has always been "something wrong" with Windex in that it leaves a ghostly film on optics. After much experimentation, I have found that it is the heavy impurities that are SUSPENDED in the solution that are responsible for the fog....you CAN get them out as you will see. NOTE that ONLY the blue Windex should be used. NEVER use any cleaner with vinegar on your optics. Kodak Photo-Flo - If you have never used this before NOTE!!! This is extremely concentrated stuff and a tiny, tiny bit goes a very long way! We are talking DROPPER amounts here....NOT ounces. DO NOT USE MORE THAN RECOMMENDED....your results will be horrible. Kleenex - ONLY USE pure white Kleenex, no other brands at all. Do not select Kleenex with "ultra softeners" or with scented oils. Only plain and simple pure white. ===HERE IS HOW TO MIX ALL THIS STUFF=== You are making TWO solutions: 1) Solution 1 - Cleaning Solution: This is the active part of the cleaning and should be mixed very precisely in the quantities provided. 2) Solution 2 - Rinse Solution: This is ABSOLUTELY necessary for most cleaning session; however, you MAY find that you do NOT NEED the final solution if your optics dry streak-free (which likely they will!). SOLUTION ONE: Cleaning Solution. You are going to have much more solution of each component than need for one quart of final SuperPlus Cleaning Solution. Keep all left-over unused and unmixed components well sealed and marked for future use. Step 1: FILTER THE WINDEX VIA THE COFFEE FILTER into a thoroughly washed and dried container; go ahead and filter the entire bottle as this is much simpler and more effective than attempting to filter one ounce. Step 2: FILTER THE DISTILLED WATER using a second clean coffee filter into another jar. Yes, I know that distilled water is supposedly inclusion free, but trust me on this one. Step 3: MIX...... In another quart jar, add the following (do NOT substitute nor change amounts!) a) the filtered and purified WINDEX - 1 ounce b) ALCOHOL - 1.5 ounce c) PHOTO-FLO - two drops...that's RIGHT, I said "two drops"....any more and you will be sorry. And I mean SMALL drops!! (about 1/16th ounce is pushing the limit) Step 4: MIX together gently but do NOT shake. Step 5: ADD 12 OUNCES OF Distilled water. I chose to mix my solution in empty quart plastic alcohol bottles; if doing so, merely fill the bottle to within 1" of the top. Step 6: Pour liquid into your MARKED squirt bottle for use. SOLUTION TWO: Rinse Solution. In 12 ounces of filtered distilled water add TWO drops (only!!) of Photo-Flo solution. No more no less. Transfer liquid into SECOND MARKED squirt bottle. You are now ready to CLEAN your optics. The ASO SuperPlus Cleaning Technique - You CAN do it right! The FIRST time! **tip #1** CLEAN OPTICS ONLY IN THE DAYTIME WITH THE OPTICAL SURFACE "LOOKING" OUT OF A WINDOW OR TOWARD A BRIGHT OPEN SKY **tip #2** NEVER....NEVER...ATTEMPT TO SURFACE CLEAN LARGE OPTICS WHEN THE HUMIDITY IS ABOVE 65% !! Streaking will result. If you attempt to clean your optics when the humidity is high, you will be very disappointed in the results. **tip #3** PLAN TO USE AT LEAST ONE TISSUE PER INCH APERTURE BEING CLEANED....ALWAYS keep a dry tissue to the surface for best results! There is no solution that will result in satisfactory cleaning if your technique is NOT good when cleaning. Unfortunately with cleaning large glass surfaces, you must normally move quickly, but gently in order to obtain a streak-free and spot-free result. If you follow this technique, you can move a bit more slowly and deliberately AND achieve the same results. ** MAKE SURE YOU HAVE DUSTED OFF THE PARTICLES FROM THE GLASS PRIOR TO FURTHER CLEANING! (see above) ** STEP ONE - Turn your telescope so that you are FACING the corrector plate or lens head-on; you are NOT going to use so much liquid that you need to be worried about cleaning solution getting away from you and down inside the retaining rings of the optics. Make yourself comfortable....you may be here a while! I prefer placing the telescope if possible in a position where I can sit down to clean. You must have a small table or area within reach where you will have your Synthetic Cotton Replacement Pads, solutions and Kleenex waiting. STEP TWO - Imagine your corrector plate or lens in QUADRANTS or quarters, like large sections of pie. You are going to begin at the TOP left and work your way down to the BOTTOM left piece of pie. STEP THREE - Gently shake the container (Solution ONE - Cleaner) for just a brief moment and spray a generous amount of liquid onto the Synthetic Cotton Replacement Pad, NOT the glass surface. You want the Synthetic Cotton Replacement Pad WET, but not dripping; make sure you hold the pad only on ONE side and do not TURN to use the side where your fingers have been. STEP FOUR - Begin in your upper left "quadrant" and gently daub (do NOT rub) this section until you have generously smeared the cleaning solution across the surface of ONLY that area. Never "push" the Synthetic Cotton Replacement Pad, only pull. Do NOT rub. The idea here is to ONLY move the liquid across the surface to break the adhesion of film and dirt deposits against the glass. MOVE QUICKLY TO STEP 5..... STEP FIVE - Before the liquid begins to collect into large areas and before any drying takes place, immediately begin wiping the quadrant just soaked with KLEENEX tissue to dry it....to do this, you want to gently PULL the Kleenex across the surface in ONE DIRECTION ONLY...do NOT go back and forth as this will streak and will tear the tissue into endless amounts of clumps that will have to be removed from the surface. You will see the liquid rapidly drying behind you. Follow each swipe IMMEDIATELY with a DRY Kleenex tissue. [reminder: keep changing to a dry tissue constantly!!] STEP SIX - When entire quadrant is reasonably dry, buff gently with a totally dry Kleenex; repeat a second time with another Kleenex while gently "puffing" a bit of your breath against the corrector plate or lens to expose possible areas of streaking. [reminder: keep changing to a dry tissue constantly!!] STEP SEVEN - Repeat same procedure on remaining three quadrants with a bit of overlap on each. [reminder: keep changing to a dry tissue constantly!!] STEP EIGHT - Check each point where areas overlapped during cleaning and "touch up" using a fresh Synthetic Cotton Replacement Pad sprayed with a VERY SMALL amount of cleaner....you want this swab nearly dry, but just enough moisture to touch up defects in cleaning. STEP NINE - Using your breath as a guide, gently "puff' against the glass while using a Synthetic Cotton Replacement Pad to buff the final cleaned surface to a high luster with not streaking! STEP TEN - [[OPTIONAL]] - USING THE RINSE SOLUTION This step is likely NOT necessary and should ONLY be used if there is any streaking left after the careful cleaning procedure outlined above. If there are problem areas, you should rinse your cleaned corrector/lens as follows: - spray a VERY SMALL amount of rinse solution onto the glass OR place some on a fresh Synthetic Cotton Replacement Pad.....you want only a tiny amount of liquid present to break the surface tension of the glass....remember, the glass is already cleaned from the CLEANING PROCEDURE. All you are attempting to do is to remove any streaks at this point. - gently rub the Synthetic Cotton Replacement Pad across the entire glass area quickly but very lightly and follow WITH YOUR OTHER HAND a fresh dry Kleenex tissue to absorb any moisture remaining from the first pass. This should take care of streaking very quickly. - again, buff the entire surface with a fresh and dry Synthetic Cotton Replacement Pad to finish. ------------------ Best of luck and take your time.....this solution and technique will work on all coated glass surfaces (NOT MIRRORS) and the solution is ideal as well for your binocular, eyepieces and camera lenses. The key to success is: 1) take your time; 2) work in small areas; 3) use LOTS of dry Kleenex; and, 4) use ONLY the materials and techniques described. Dr. Clay ---------------------------------------- Arkansas Sky Observatory www.arksky.org 6eda4db2ad8777a253870558ec84210c423761f0 0 190 228 227 2013-05-12T02:51:30Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki The best way to clean a mirror is to not get it dirty ever! '''Don't ever touch the front of a mirror!''' Since you are reading this I'll assume that, like me, you have let your mirrors get dirty. Cleaning a first surface mirror will damage the surface so it is our goal to damage it as little as possible. We will assume that, like most mirrors, yours is aluminum with a protective overcoating. For instructions on cleaning mirrors that are dielectric coated (not silvered) see [[Cleaning Coated Optics]]. The first thing to try is gently blowing the mirror off with compressed air. Use a commercial can or make sure your compressor air is filtered and dried. If that doesn't get it clean, or clean enough, you'll have to go the more dangerous route. ==Washing your mirror== [[Image:NalgeneBottle.jpg]] A Nalgene Wash Bottle can be useful to store solutions used for washing. The next thing to try is to wash the mirror. A common amateur astronomy recipe is to take 5 gallons of warm water (not hot) and add 1 teaspoon of '''Ivory Liquid''' dish washing soap. Bob Hess recommends using more soap, Like 1 oz per Liter of '''distilled''' water. *Mount the mirror face up in a sink, so that it's off the bottom. (You don't have any rings on right?) *Be certain to thoroughly clean the sides and back of the mirror, without touching the front, before attacking the front. Otherwise, you will probably contaminate the cleaning fluid with particles that will scratch the coating. *Blast off loose dirt with water flow in the sink. *Rinse with distilled water. *Prepare some surgical cotton wads cut from a large roll into a bunch of grapefruit sized pieces. Don't use cotton balls. They turn to mush and seperate in the soapy water. Get a big roll of surgical cotton at the pharmacy, and make a bunch of grapefruit sized wads before wetting the mirror. *Pour some of the soap solution onto the middle of the mirror. Wet a cotton wad, and use it to move the soap from the center straight to the edge, in a spoke like pattern, turning the wad to use a new face for each wipe. Let the weight of the wet cotton be the only force on the mirror. (Do Not Rub!) *Add more soap and/or distilled water as needed. *Use the last of the soap and the cotton wads to gently swish around on the surface. *You may remove the mirror to examine it but do not let the soapy water dry! No longer than 30 seconds! *Rinse with a gallon of distilled water. *Follow that with 99% isopropanol, and blow dry fast with a hair dryer. *Touch up any residual marks with methanol on lens tissue. *Check mirror for any dust that settled during drying. Remove with a new fine point artists brush. Now you should have a clean mirror. Try as much as posible to keep your mirrors clean to avoid the risk of damaging them when cleaning. ==Using Collodion== The subject of using collodion came up on the [http://www.holographyforum.org/phpBB2/index.php Holography Forum] with and collodion has been used for some time by astronomers to clean their [http://webari.com/oldscope/atspages/techtips.htm precious mirrors]. Note that you should be careful using collodion on cheap mirrors as it [http://www.dragonseye.com/blog/archives/92-Optic-cleaning-with-collodion.html can remove the silver]. If it's truly a cheap mirror though, you may just want to replace it. The first thing to do is create a tape dam around the mirror so the collodion doesn't just drip off the edges. http://www.dragonseye.com/gallery/d/3690-2/06020004.jpg Follow that by pouring a small amount of collodion on the mirror and rotating the mirror in a circle to distribute the liquid. This will take a bit of practice but it's easy to repeat the process after the collodion has dried. Once the collodion has dried (anywhere from five to ten minutes) remove the tape and you should find that the collodion will come up with it if it hasn't already started to curl up on its own. If any of the collodion stays behind you can either remove it with some tape or dribble a bit more liquid on the stuck part and you'll find it's easier to remove after the new liquid has dried. You should find that after a treatment with collodion that the lens or mirror is as clean as it was when new. http://www.dragonseye.com/gallery/d/3699-2/06020008.jpg ==Mirror Cleaning an Observatories Approach== Used with permission from http://www.arksky.org/asoclean.htm#mirrors. ===THE CLEANING OF OPTICAL SURFACES: MIRRORS=== Front surface mirrors, secondary mirrors and mirrored diagonals by P. Clay Sherrod, Arkansas Sky Observatories The cleaning of front surface mirrored surfaces is much, much different than that of refractive optics; many times the reflective surfaces might be of deposits of enhanced silver or aluminum which may or may not be overcoated with some protective layer (usually a molecule-thick layer of Silicon Dioxide or similar) of transparent material. Your first step in attempting to clean ANY reflective optics is to first ascertain whether or not your mirrored surface is indeed protected by such a coating, since the cleaning solution AND procedure to clean without damage is quite specific for protected vs. unprotected mirror surfaces. Note that the following discussions include all reflecting optics: primary mirrors, secondary mirrors (both flats and curved), mirror diagonals and any ancillary optical equipment which uses a mirror in the optical interface. ===DETERMINING MIRROR PROTECTION=== A very simple rule for deciding whether or not your mirror surface is protected: if you do NOT know, assume that it is NOT coated. Most manufacturers of Newtonian mirrors supply the finished product with a coating of silicon dioxide over the final aluminized or silvered coatings; ASK whether your mirror is coated....if you cannot get an answer, then assume that it is not. On the other hand, most primary and secondary mirrors of popular catadioptic (Schmidt-Cassegrain and Maksutov) are NOT protective-coated unless otherwise specified. There is a good reason that many manufacturers do not put protective coatings on telescope mirrors: they can reduce performance, both in terms of optical figure (irregularities in deposited protective coatings can change the wave front of your mirror) and in terms of reflectivity (many new mirror systems have "enhanced" coatings which contain highly reflective alloys in addition to aluminum. However, since most enhanced coatings also contain the element SILVER, and since silver tarnished instantly with exposure to oxygen, the chances of enhanced optics being overcoated are pretty good in your favor. Attempts to clean uncoated optics can result very quickly in permanent damage: sleeking (leaving streaks within the coatings themselves) or spotting is very common, even if the utmost care has been used. Never, should any cleaning agent whatsoever be used on unprotected mirror surfaces or damage will occur 100 percent of the time. Simply do not take the chance. ===CLEANING IN RELATION TO MIRROR ACCESS=== In some modern telescopes, it may be undesirable OR even impossible to totally remove the primary mirror for the typical consumer and end-user; thus cleaning will likely take place less often than it would if the mirror were smaller or easy to remove from the optical tube assembly. Remember my Number One Rule on Optics Cleaning: "Don't....unless you absolutely have to." Number Two Rule is: "Brush first and then determine if cleaning is still necessary." Brushing optics and carefully using compressed air to blow off particulates such as pollen and dust can usually get the mirror or optics back into top shape, and cleaning should be done only if there are stains or excessive spotting beginning to build up on the mirror's surface. With catadioptic commercial telescopes, cleaning the primary should be avoided at all costs....prevention is the best care you can give the optics of these telescopes: keep the back opening plugged at all times, even when briefly removing accessories....plug it up until you are ready to insert a new gadget. This keeps both dust and insects from floating in AND it prevent humidity and damaging environmental pollutants from entering the inside of the OTA. In one of the following procedures, not that I discuss cleaning (essential cleaning only....) the mirror of a commercially-built catadioptic by leaving the mirror IN PLACE. Never attempt to remove the mirror of these telescopes unless you have experienced and competent assistance. ===CLEANING SOLUTIONS FOR FRONT SURFACE MIRRORS=== To preface any discussion about what is needed for cleaning mirrors, it is important to note that complete immersion cleaning of most large (i.e, Newtonian) mirrors is recommended, and thus the "solution" quantity is much greater. There is no need to make up batches of cleaning solutions and store....just make it when you get ready to clean your mirror. Essentially all that you are going to need are two pairs of surgical cotton gloves, a clean terrycloth towel, a small amount of IVORY dishwashing liquid, a jug of distilled water and a few white Kleenex tissues.....oh, a large sink, bathtub, or basin. Conversely, to clean unprotected mirrors requires ONLY a very small amount of high pure alcohol content solution and nothing more, since ONLY spot cleaning should ever be attempted; if any unprotected mirror surface becomes so pitted or stained that whole-mirror cleaning is needed.....it is time to send the mirror and/or OTA in for a complete re-coating job. No exceptions. ===CLEANING MIRRORS WITH PROTECTIVE OVERCOATING=== Again, if there is any doubt whatsoever that your mirror has protective overcoatings, assume that it does NOT have protection or be prepared to face the consequences. IMPORTANT NOTE: rarely do secondary mirrors and diagonal mirrors have any protective coating; always assume that they have front surface exposed enhanced coatings and never clean except as described later. 1) In a basin large enough to hold your mirror and still have adequate room for your hands to grasp around the edges, prepare a solution of the following: (based on one-half full kitchen sink quantity....this does not have to be exact! For larger basins, such as a bath tub or wash tub, use proportionately similar detergent-to-water ratio) a) warm, not hot tap water in which you have added ONE TEASPOON of Ivory Liquid dishwashing solution....do not be tempted to use more. b) a thick folded towel placed on the floor of the basin; c) turn off all fans, vents and central heating/air during this process! 2) Remove all jewelry, including wrist watch and put one pair of the TWO pairs of new surgical cotton gloves on your hands 3) For Newtonian and similar mirrors, first remove the mirror and its cell from the telescope OTA; then remove the mirror from the cell...remember, NEVER touch the front surface of your mirrors...your fingerprint contains acid and oils and can be the most damaging element to your mirror! NOTE: as with all glass, telescope mirrors become incredibly slippery and hard to handle when wet. Make every precaution to protect the mirror and you will be safest is you "assume the worst" and prepare for the mirror to slip. This means putting a large folded clean towel in the floor of the basin in which the cleaning will be done; having another clean towel folded against a wall and resting on the floor where the mirror will dry. 4) Place the mirror FACE UP carefully down in the basin, resting on the towel, making sure that you have enough solution to completely cover the entire top surface completely. 5) Allow mirror to soak for at least 5 minutes but NO LONGER than 15 minutes. Do not touch the surface of the mirror at this time. 6) While soaking mirror, remove the cotton gloves and place them in the solution with the mirror to prevent contamination. 7) After about 5 minutes refit gloves but do not touch anything outside of the basin; at this time you are going to very, very gently - with NO pressure - massage against the front surface of the mirror with the tips of your fingers....do NOT rub and do not use any type of cloth or tissue at this point, only fingertips [[note that you MAY use Kim-Wipes or Intrinsic type pads for this process]]. It is fine to "lay down" your fingers and cover more surface.....your are essentially "buffing" the entire surface with the dishwashing liquid using only fingertips. 8) Once done, rotated the mirror 90 degrees and once again massage the entire surface. 9) Occasionally tilt the mirror out of the water for only 30 seconds maximum and examine it.....if there are places that you missed, it will be obvious; if need be, run a very gentle stream of water out of the tap or pour from a pitcher across the mirror and examine while wet; return to basin and massage needed areas until entire mirror is uniformly clean and free of streaks. 10) Leaving the mirror flat in the basis, remove all soapy water from the tub but LEAVE the towel beneath the glass for safety; as the water recedes, begin flushing the surface of the mirror immediately with cold tap water...NEVER ALLOW THE MIRROR SURFACE TO DRY! 11) [note: an assistant is quite helpful at this point!] - Once the mirror has been flushed adequately with tap water, begin tilting the mirror upward at about a 45-degree angle; placing an adequate mass of towels behind it is helpful, but careful to not let the mirror slip in the basin! CONTINUE flushing with tap water while doing this...do not let the mirror go dry......have a pitcher of distilled water within reach and shut off the tap water, and immediately flush with distilled water; allow the flush to drip off the mirror and do it again, using only distilled water. 12) REMEMBER - your gloves are soapy....once you have reverted to the distilled water rinse REMOVE the cotton gloves and work with your bare hands only, being careful to only touch the edge of the glass and never touch the optical surface. 13) Lift the mirror out, keeping the surface vertical to the floor and immediately place on the waiting towel on the floor and lean the mirror carefully at a sharp angle against a wall....use extra towels to assure that the mirror will not roll nor tumble. The angle allows the liquid to roll off the surface, thereby reducing substantially the amount of dry water spotting that can occur. NOW, put the second pair of cotton gloves on your hands for safe handling of the mirror from this point forward. 14) After only TWO MINUTES maximum in the drying position (#12), identify any beads of water that are NOT rolling off the surface; these can be easily removed by "wicking", a process in which you roll up a white Kleenex tissue into a "pencil" and touch to the drop...NEVER RUB.....the tissue will wick the water up off the glass and safely away. 15) Allow to air dry, (with ALL VENTS from air conditioning/heating closed!) for one hour. 16) Some dust might accumulate during the drying process....use a quality soft artists square tip (see Cleaning Refractive Optics, Part One) brush to remove such lint, but ONLY after one hour of drying time! ===CLEANING PROTECTED MIRRORS WHICH CANNOT BE REMOVED:=== The above procedure allows for cleaning a primary mirror which can be removed and immersed in a basin; some protected mirrors (i.e., larger Newtonians, some newer SCT and RC catadioptic telescopes) are made in such a way that mirror removal is very difficult or should NOT be attempted. You clean this in three steps. [DISCLAIMER: From experience, I will state that such mirrors should NOT be cleaned, only brushed and blown off with compressed air; I do not, nor does ASO, recommend the following cleaning procedure; the following procedure can be used by skilled and experienced persons in telescope maintenance, but is not recommended for the normal owner/operator of telescope systems. This is the procedure and technique used in the ASO Supercharge and only used when absolutely necessary, and we do not assume any liability from product damage from any attempts at such cleaning.] CLEANING LIQUID: For such surfaces, use essentially the same process, but instead of immersion, we are going to give your mirror a "sponge bath" applying the soapy liquid (about one gallon water to each one-half teaspoon of Ivory dishwashing liquid). For this you will NEVER USE TAP WATER, only distilled water for both cleaning and rinsing. RINSING LIQUID: You will also need ONE OUNCE of pure (91% or higher) isopropyl alcohol and one capful of Kodak PhotoFlo per gallon of distilled water for RINSE (not wash). The application of both solution AND rinse MUST be done using either Kim-Wipes (Kimberly-Clark) or Intrinsic Pads (Barnhardt Industries of South Carolina)...never, ever use any cloth, tissue or "lens cleaning cloth" for this cleaning or damage will occur. FINAL RINSE: A final rinse of pure distilled water is absolutely imperative...you must do this final step. 1) Place first pair of cotton gloves on hands 2) Have your one gallon of cleaning solution (distilled water with 1/2 teaspoon of Ivory Liquid) handy with a pad soaking in it; likewise you must have your gallon of RINSE solution (gallon of distilled water with one ounce of pure isopropyl alcohol and one small capful of Kodak PhotoFlo) ready with pad soaking it that as well! Your final rinse with pure distilled water needs to be made immediately, so have that ready as well. 3) Put the telescope so that the mirror is angled sharply, i.e., nearly vertical to the ground....your access to the mirror will limit what angles you might be able to achieve here. 4) Making sure that the wipe or pad is ALWAYS completely soaked, but not dripping all over the inside of the OTA, gently begin wiping (Never rubbing!!) across the top 1/2 of the mirror surface; immediately ...during this process, it is absolutely imperative that you continue to resoak and freshen the cleaning pad...never let it dry out so much that surface tension increases against the glass!! 5) Even though you have only done 1/2 of the mirror (always start at the top), you must now quickly RINSE what you have cleaned, using the fresh pad in the rinse solution; keep an abundant (but never dripping) amount of rinse liquid always against the glass! Once the rinse is made, cover the mirror surface that you just cleaned with adequate distilled water final rinse and proceed to clean the lower one-half of the mirror. 6) Once both halves have been cleaned and initial rinse completed, return to the entire mirror and wipe down with copious amounts of distilled water final rinse (no alcohol); repeat twice. Never use so much that your pad is dripping into the telescope tube assembly. 7) Check for water drops that are not quickly evaporating....use a "Kleenex pencil" as a wick to soak up those drops...never rub! 8) Allow to dry in vertical position, with OTA end cap open but with soft cotton sheet over front, for about one hour. 9) Remove any lint or dust with brush or blow off, but do not attempt until after one hour. USE EXTREME CARE IF ATTEMPTING THE AFOREMENTIONED PROCESS and never attempt unless it is absolutely imperative. ===CLEANING MIRRORS WITHOUT PROTECTIVE OVERCOATING=== Very much unlike the previous discussion, cleaning unprotected mirror surfaces should be a "last resort" and is NOT recommended to the normal telescope user. Only if fingerprints, bug droppings, pollen sap, etc. collects on the unprotected mirror surface should any attempt be made to clean. Brushing is encouraged, but cleaning is discouraged. For this cleaning, you need ONLY a quart bottle of pure isopropyl alcohol (91% is the minimum....94% is far better) and either Intrinsic wipes (Barnhardt Industries) or pure white Kleenex with no additives....NEVER use cotton or cotton balls to clean. Never use Q-tips for cleaning small surfaces, only the pads or tissues as specified. NEVER attempt to clean the entire surface of ANY unprotected mirror, whether it be a primary mirror or a small flat mirror in your diagonal assembly. Clean ONLY spots and areas needing cleaning. IMPORTANT: never attempt to clean any spot larger than one inch using this procedure. Use only the following procedure: 1) Place a bright light so that it shines directly onto the surface to be cleaned; you need to be able to see the reflection of the light as well as move your line of sight to inspect so that the light does not shine directly back at you; viewing both ways allows you to examine for streaks and also can assist in preventing you from "over-rubbing" any cleaned area; 2) Put on cotton surgical gloves and locate your area to be cleaned. 3) Put ample alcohol onto your pad or tissue, making it soaked, but not dripping. 4) Very gently wipe the solution across the stain...do NOT rub at all...not one bit. Rubbing will remove your coatings! 5) Follow that wipe with a second one using a totally different wipe or tissue, also soaked with alcohol. 6) Finish by wiping off excess with a fresh dry wipe.....no rubbing, only a light swipe across the surface! This method can be used on secondary mirrors, unprotected primary mirrors and enhanced coated diagonal mirrors. HOWEVER, such cleaning is a last resort....never clean unnecessarily and never clean unless it must be done. Remember what we have always preached at ASO: the single most damaging thing that you can do to your precious telescope optics is to CLEAN THEM. While it is perfectly safe to clean the protected primary mirror OR the front corrector plate of a catadioptic (ASO Part One), it is an entirely different undertaking to clean unprotected mirror surfaces. My utmost recommendations concerning cleaning of unprotected mirrors? DO NOT ..... Let those with experience do it for you or live with the small imperfections....when they get too big, it is time for new coatings. Best of luck and enjoy your telescopes...may the stars always shine their brightest through them. Another quality service from your Arkansas Sky Observatory! Part III (coming soon...): "Preventing the Need to Clean - Protecting your Telescope Optics" Dr. Clay ---------------------------------------- Arkansas Sky Observatory www.arksky.org 909f6c9fc0347095ce56ca06e77f4246cbf89078 0 191 230 229 2013-05-12T02:51:30Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ===Kris Meerlo's Coating Machine=== Some pictures from my new home made coating machine: [[Image:KrisCoatingMachine.jpg]] Some specifications: -Temp control ( roomtemp to 70 C ) -Variable speed control. -cooling with fans. For the temp control I use the amazing sauna belt from amazing discoveries incl a digital temp controller from Conrad electronics. For quick cooling off the aluminium heating plate I use harddisc drive cooling fans. I tape the heat tracing from the Sauna belt on the Alu plate with heat resistance alu tape. The movement of the meyerbar is variable. ( I "stole" some ideas for the coating machine from the internet ). And I have some ideas from Hans. ===Hanz' Coating Machine=== [[Image:HanzCoatintMachine.jpg]] One problem I have found with my machine is the following: If I use normal glass that has only been cleaned with Glassex window cleaner, the machine produces a nice and flat coating. But if I pre-treat the glass with silane, the glass becomes hydrophobic. This has a negative effect on the flatness of the coating because the gelatin wants to run of the glass in any direction it can while it is still liquid. 84181922941c8041966dea332f3b4f26ca49d0be 0 192 232 231 2013-05-12T02:51:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Coating a plate with gelatin of even thickness is a demanding task. It is quite important that the coating be of a uniform thickness. There are many methods for coating a plate listed below: [[Veil Coating (with Spin or Lean)]] [[Myer Bar Coating]] [[Spin Coating]] [[Mold Coating]] [[Coating Machines]] [[Prepping Glass]] for coating. d788fa834f701756126c0e437ee33966137483a1 0 193 234 233 2013-05-12T02:51:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:Colink.jpg]] Colin Kaminski is an amateur holographer who in a state of extreme frustration and needing advice started the forum that has become the [http://www.holographyforum.org Holography Forum] and now this Wiki. He really has no other holography releated acomplishments other than about 100 or so 4x5" and smaller holograms given to children. He has worked as an Assembly Language Programmer, Motorcycle Mechanic, Luthier, Theatrical Lighting Designer, Product Designer and now he is the Master Brewer at [http://www.downtownjoes.com Downtown Joe's] in Napa, CA. [http://www.designerinlight.com Colin Kaminski's Web Site] [[Image:Colinemail.gif]] b5f991a712c1fd534d9906ff0fc3b63ac38f6899 0 194 236 235 2013-05-12T02:51:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:CIEDiagram.jpg]] 5a100b415dd5ba1b49b021495dd5b2dc3db63f0f 0 195 238 237 2013-05-12T02:51:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki The basic mathematics of computer generated holography are well understood. The major difficulties are in two areas - computer resources and output media. *As we increase the angle between the computed reference beam and the computed object beam, the fringe spacing becomes smaller and so the data set becomes very large. This requires vast amounts of data storage and computation time. Much work has gone into algorithms to simplify the calculations, but producing high quality imagery is still a difficult problem. *As the fringe spacing decreases, we require higher and higher resolution printout to a transparency. Electron beam lithography is one method used for very high resolution output, but the equipment is extremely expensive and is typically only designed for small imaging areas. These problems have made it so that only On-Axis (Gabor) Holograms and Fresnel Holograms are commonly produced nowadays. ===Recording holograms on CD-ROMs=== One possible high resolution medium is the surface of a CDROM. This has been explored and even used in such disks as Microsoft Windows Installation Disks. The software required to write this kind of dataset requires bypassing the driver software as the driver software limits the types of data possible. Also, there is no easy way to align successive tracks on a CD ROM. Some of the new CD ROM drives are capable of writing images to the front surface and may prove to be more suitable to hack into. There was a presentation at SPIE / IS&T Electronic Imaging 2004 (Practical Holography XVIII: Materials and Applications), which will be SPIE Proc. 5290: Computer-generated holograms on a CD-R disk, Y. Sakamoto, Hokkaido Univ. (Japan); M. Morishima, A. Usui, Yamaha Corp. (Japan) [5290-02] [http://adsabs.harvard.edu/abs/2004SPIE.5290...42S journal article info page] Colin Kaminski contacted Y. Sakamoto and was told that this project was abandoned by the manufacturer and this code was no longer available. [http://www.medcosm.com/prog_CGHmaker.htm MedCosm Computer Generated Holograms] [http://www.instructables.com/id/EKXB9DF5V7EP286HE7/?comments=all "Instructables" do-it-yourself page] ===Binary Detour=== 9294c8150571a03ebac6f52b94f0ac2918f8bb19 0 196 240 239 2013-05-12T02:51:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki 1801 Thomas Young performs Double-slit experiment. 1881 Albert Michelson invents the interferometer. 1891 Lippmann photography developed. Natural color photography through the interference of light. 1900 Dennis Gabor born in Budapest. 1948-9 Dennis Gabor publishes the seminal papers on wavefront reconstruction and holography is born - but the laser is not yet available. 1960 Theodore Maiman makes the first visible-light ruby laser. 1962 Lieth & Upatnieks develop off-axis transmission holography based on side-scanning radar. 1962 Denisyuk produces the first white-light viewable hologram. 1965 First paper on holographic interferometry published by Powell & Stetson. 1967 DCG process developed for holography. 1967 Larry Siebert of the Conductron Corporation makes the first hologram of a person. 1967 World Book Encyclopedia published which includes the first mass-produced transmission hologram. 1968 White light (rainbow) transmission holography developed by Stephen Benton. 1970 Sandbox system developed by Pethick and Cross. 1971 San Francisco School of Holography opens. 1971 Dennis Gabor awarded the Nobel prize for holography. 1972 “Kiss” Integral hologram developed by Lloyd Cross. 1974 Hologram embossing developed. 1976 Museum of Holography opens in New York. 1979 Dennis Gabor died - London. 1983 First hologram appears on a credit card from MasterCard. 1984 National Geographic puts rainbow hologram of an eagle on their cover. 1985 National Geographic puts larger rainbow hologram of a skull of early man on their cover. 1988 National Geographic features a full-cover rainbow hologram of the world. 1988 Photopolymer film developed by Polaroid. Allows very bright reflection holograms to be mass produced. 1992 Museum of Holography in New York closes. 1993 MIT acquires complete collection of the Museum of Holography. 1999 Geola patents printers for color digital hologram printing with pulsed lasers. 2000 First digital color hologram produced by Geola with a pulsed RGB laser. 2003 Stephen Benton dies. 2005 Emmett Leith died. 2005 The first color portrait hologram shot at Geola with HoloCam equipment and printed with a digital RGB printer. 2006 Yuri Denysiuk died. 2008 Geola's digital holograms named i-Lumograms - Integrated Light Writings. References: *Saxby, Practical Holography, ISBN 0750309121 *Unterseher, et. al Holography Handbook, ISBN 0894960164 *http://www.holokits.com/a-teaching_holography.htm *http://www.holokits.com/a-make_holograms_p2.htm *http://www.holokits.com/a-Types_of_Holograms.htm *http://www.holophile.com/history.htm *http://www.holography.ru/histeng.htm *http://chem.ch.huji.ac.il/~eugeniik/history/lippmann.html *http://nobelprize.org/physics/laureates/1908/lippmann-bio.html *http://nobelprize.org/physics/laureates/1971/gabor-autobio.html *http://www.commonsensedirections.org/html/Adjunct%20Pages/Theodore%20Maiman.htm *http://people.deas.harvard.edu/~jones/ap216/lectures/ls_2/ls2_u5/ls2_unit_5.html *http://www.xmission.com/~ralcon/dcg-refs.html *http://www.jfairstein.com/SOH.html *http://web.media.mit.edu/~sab/ *http://nobelprize.org/physics/educational/laser/facts/index.html http://www.geola.lt/show.php?lang=eng&cont=holo_history&lside=holo_index_left (taken from A Consise History of Holography by [http://www.dragonseye.com/blog Michael Harrison], any errors are mine. Once I figure out how to add pictures I'll add the thumbnails that go along with the document - msh) 158d1870ac8693045e2a6862500bd90604396c1a 0 197 242 241 2013-05-12T02:51:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Concrete is a mixture of Portland Cement, sand, gravel and water. As an engineering material it only works in compression. Any tension and the concrete will crack. Concrete structures are designed with metal bars or cloth inside to support the tension loads of the structure. Concrete can be mixed from the scratch raw materials (above) or can be bought already pre-mixed needing only the water added. When mixing concrete add just enough water to make the concrete just loose enough to be pushed into the desired form (mold). If anything, on the stiffer side is better then on the runny or loose side. Just after pouring concrete a screet is used to level the concrete to the top of the form. A screet is usually just a very straight piece of long wood. The screet is placed on both sides of the form and pushed back and forth while being pulled in one direction. This levels the concrete. The excess concrete usually overflows over the side and at the finish of the screeting process. Then after the concrete has set up partially (enough so that you are able to press one of the grave stones down into the mixture but it requires some force) a concrete float (usually aluminum or magnesium) is used to press the gravel down into the concrete and "float" the portland/sand to the top. This leaves a nice smooth top. This can be done once to serveral times and for a finer finish and a fine spray of water can be added to the top of the setting concrete just before the second or subsiquent floating proceedures. This additional water also help the curing process. It is also at this point you can press your hand into the concrete to preserve you hand print for a very long time, or sign you name in the concrete. It should be noted that concrete does not DRY. It cures. It will cure to a harder product if youkeep the surface wet for a few days. A wet carpet on the surface works well. 18cc11c5ea3fe048ee08114ca1a1def64d3cda51 0 198 244 243 2013-05-12T02:51:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Unless otherwise stated by the author the copyright for the HoloWiki will be GNU Public Documentation License as follows: Copyright (C) 2000,2001,2002 Free Software Foundation, Inc. 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. 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If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software. 67b097f4a3b57a00f7c1021260021f54e13518b1 0 200 248 247 2013-05-12T02:51:33Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==Cr4+:YAG Passive Q-Switch== *Formula: Cr4+:Y3Al5O12 *Crystal Structure: Cubic Garnet *Density: 4.56 g/cm3 *Hardness: 8.5 (Mohs) *Damage Threshold: > 500 MW/cm2 *Refractive Index: 1.82 @ 1064 nm *Recovery Time 8.5 µs *Repetition Rate > 30 Hz *Orientation <111> cubic *Absorption of Ground State Level 5.7x10-18 cm2 *Absorption of Exited State Level 8.0x10-19 cm2 Available in initial transmissions of T=40% to T=99% and thicknesses up to 5mm. Maximum transmission is at a fluence of around .6 J/cm^2. 240806bdbfb247ad72b836731a0790ca2faeaa5d 0 201 250 249 2013-05-12T02:51:33Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Because of the expense of making these crystals they are usually quite small. The can be quite thick compared to other mediums and can store a large number of holograms. The exposure energy is quite high and they are erased by light so reading the stored hologram degrades the image. Some researchers have gotten around the erase problem of these crystals. For further information see the the references at the bottom of the page. ==Lithium Niobate== Fe-doped LiNbO3 crystals have been used to store holograms. These crystals are only Available in small sizes but they are available in large thicknesses compared to traditional materials. This thickness can be used to make holograms that can be made to read different holograms when the reference beam comes from different angles. Reading the hologram at the same frequency as writing it will cause degredation of the image. The exposure requirement is quite high at about ^4 J/m^2. The interested researcher should refer to Petrov, M.P. (1979) Light diffraction from volume holograms in electro-optic bifringent materials. Optics and Laser Technology. 11, 149-151. ==Barium Titanate== BaTiO3 ==Sr.75Ba.25Nb2Og== ==BSO== Bi12SiO20 Exposure requirement - 3J/M^2. This material is used with an applied field perpendicular to the fringes. This applied field can be up to 900V/mm. Information storage length for dark storage is reported to be only 30 hours. ==BGO== Bi12GeO20 ==References== Optical Holography, P. Hariharan, 1996, ISBN 0521439655 52216d19493eadf5db5b6546072e8ea3c8087531 0 203 254 253 2013-05-12T02:51:33Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Daguerreotype''' - first practical and commercial photographic process, introduced by Louis Daguerre in 1839. The sensitive material comprised silver iodide, deposited on a polished silver plated copper base. A positive image was produced by camera exposure and mercury "development", which turned light struck halides gray-white. The image was made permanent by immersing the plate in a solution of sodium chloride. *'''Daylight enlarger''' - early type of enlarger using light from a hole in a window to provide illumination of the negative. *'''Desensitizing''' - reducing an exposed emulsion's sensitivity to light. This can be done by the application of dyes or by using oxidation agents *'''Developer''' - chemical bath containing reducing agents, which converts exposed silver halides to black metallic silver, making the latent image visible. *'''Development''' - process of converting exposed silver halides to a visible image. *'''Diazo''' - abbreviation of diazonium compounds, which decompose under the action of intense blue or ultraviolet radiation, forming an image in an azo dye. *'''Dichroic filters''' - produced by metallic surface coatings on glass to form colors by interference of light. Used in high quality color enlarger heads. *'''Dichroic fog''' - purple-green bloom usually seen on negatives and caused by the formation of silver in the presence of an acid. *'''Dilution''' - reduction in the strength of a liquid by mixing it with an appropriate quantity of water. *'''Dimensional stability''' - substance's ability to remain unchanging in size when subjected to processing and drying. *'''Dish development''' - method of development used for processing single sheet, cut film or paper by immersing in a shallow dish of developer and agitating by rocking the dish. *'''Documentary photography''' - taking of photographs to provide a record of social and political situations with the aim of conveying information. *'''Dodging''' - control of exposure in photographic printing achieved by reducing exposure to specific areas of the paper. *'''Dry down''' - refers to the amount a print darkens after drying. *'''Dry mounting''' - method of attaching prints to mounting surfaces by heating shellac tissue between the mount and the print. *'''Dye destruction process''' - method of producing a colored image by partially bleaching fully formed dye layers incorporated in the sensitive material. *'''Dye-image monochrome films''' - black & white negative films designed for color processing. *'''Dye sensitizing''' - defined as all silver halides used in black & white emulsions are sensitive to blue light. Early photographic materials possessed only this sensitivity.''' *'''Dye transfer print''' - method of producing color prints via three color separation negatives. Negatives are used to make positive matrixes, which are dyed in subtractive primaries and printed in register. *'''Dynamism''' - picture structuring which relates to a sense of movement and action. 30e028a8809dbdd048e71dc51206b2594f192e7a 0 204 256 255 2013-05-12T02:51:34Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Dichromated Gelatin Chemistry]] ff3322ac04e57c17933b0a410293ac9a872e4c31 0 205 258 257 2013-05-12T02:51:34Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki For an overview see [[The Mechanics of Gelatin and the DCG Process]].. ===Dark Reaction=== '''Can you elaborate on dark reaction?''' '''Jeff Blyth responds:''' A good question ! ----- It needs a chemist to do it justice because it is complicated. Although it straightforwardly means dichromate reacts slowly with gelatin at room temperatures without light being involved, it does need some explaining. If you are not interested in the finer chemistry detail then stop reading here . Most oxidizing agents such as oxygen in the air, nitrates (saltpeter as in gunpowder etc) , and chlorates can be mixed with combustible materials and just sit there inactive virtually forever unless something such as a lighted match gives them that vital spark which triggers the chain reaction and rapid burn up. So these oxidants need what’s called “activation energy” as a kick start. However in the case of dichromates the chromium is a member of what are known in the Periodic Table as “transition metals” . These are inclined to have the peculiar ability to indulge in low activity with little activation energy which is why they are used universally as catalysts for low temperature reactions. They have variable valency which is why we have referred in this forum to CrVI going to Cr V going to CrIII The transition metal iron in our blood is doing this sort of low temperature oxidation work for us of course too. The transition metal effect is to do with atomic orbitals where the electrons have a large array of complicated empty orbitals to whizz about in some of the time and to get through barriers without having to be kicked to jump over the normal activation energy barrier that non- transition metal ions have to do. A non- transition metal such as say Aluminum which is always Al III in our water based alum chemistry here and cannot be reduced or oxidized to a different valency but it does make complexes with the gelatin and hardens it (but not quite as strongly as CrIII). So back to dichromate which has 6 electrons missing from its uncombined metallic state. The electrons have been taken mainly by 3 oxygen atoms in a not very strong arrangement and these electrons are actively whizzing around the Cr atom’s empty orbitals as well as their main base around the oxygen atoms. Energy is gained for the system if 3 of them can return permanently to the Cr atom by being instrumental in getting the oxygens to swap them for other electrons in neighboring organic groups in the gelatin to give more stable arrangements producing partially oxidized gelatin. So the dark reaction of dichromate is primarily a matter of oxidation of the gelatin without a kick start with light energy or extra heat and it can be slowed down in a ‘fridge but needs to be in a freezer to really slow it down. Incidentally the less pure the dichromate the more it contains other transition metals such as copper and the more it enables this catalysed oxidizing effect to occur in the dark. More acidity also increases it which is why the more acidic ammonium salt in unexposed gelatin film gives it a shorter shelf life than the potassium salt. ===Gelatin and Anti-Crystallization Properties=== Let’s remember that yet one more of the great features of gelatin is its ability to hold quite concentrated solutions of salts within itself as a form of gelled solid solution. This is a great feature for us holographers because without it some of our valuable techniques would be spoiled by the normal crystallization processes which would transform glass clear film into the equivalent of frosted window glass. This special anti-crystallization feature can be undermined if we allow concentrated salt solutions to crystallize on the surface of the gelatin because it can then encourage crystal seeding to occur within the gelatin. So if one is making a “G307” system where the coated gelatin is dipped into a bath of say 6% potassium dichromate one needs to gently wipe off the excess droplets of dichromate salt off the surface before drying . (This system needs high dichromate salt concentrations for exposure to 532nm but NOT if one is exposing with blue wavelengths.) This also applies to the diffusion system for making silver halide gelatin film, where careful removal of silver nitrate solution in surface droplets is needed before drying and immersing in the bromide bath. Another (but less common ) way that anti -crystallization property can me reduced is by excessive drying by overheating so that the inherently bound in water found in normal gelatin film is driven off or the salt-laden gelatin is stored under very low humidity. Jeff ===Converting Dichromate to Chromate=== I hope I can just clarify something about potassium dichromate versus chromate. You can readily convert dichromates into chromates by adding the right amount of alkali to a stirred solution of say 5% potassium dichromate until it gets to a pH of about 8 to 9. The chemistry really is straightforward enough. I will just run through it for future reference. Potassium chromate is the potassium salt of Chromic Acid : H2CrO4 where the 2 acid H's are substituted for 2 K's Now to see how potassium Dichromate (K2Cr2O7) is made up, please just note down the total formula from adding one potassium chromate (K2CrO4) to one chromic acid (H2CrO4). You then get a total of K2H2Cr2O8 . now just take away 1 H2O and you get K2Cr2O7. So dichromates are all just 1:1 combinations of chromate salts with chromic acid. There is of course no need to use potassium hydroxide to do the conversion, Na OH will work just fine. I have just calculated that 100 ml of 5% K2Cr2O7 will require 1.36 g solid sodium hydroxide to convert it all to the chromate form. (The colour of the solution changes from the intense orange yellow to a light canary yellow when the conversion is complete.) Some of you will have already spotted that 5% K2Cr2O7 solution has got more chromium compound in it than the intended 5% K2 Cr O4 solution. To make it equivalent you need to cut down the volume of solution used by a third. But I don’t think this is a critical issue . Jeff 6a8c4153a84a1246ba37681491a3ca1582622227 0 206 260 259 2013-05-12T02:51:34Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki == Here are variables and their effect on the DCG process == '''AmDi concentration''' - Lower redder less sensitive, higher bluer more sensitive '''Drying Temperature (Low ~20C)''' - Lower yields more triple helices, thus harder gelatin, clearer and more narrow band '''Drying Temperature (High ~30C)''' - Higher yields less triple helices, thus softer gelatin, less clear and more broadband '''Emulsion thickness''' - Thicker more narrow banded less light gets through, thinner more broadband '''Emulsion temp while mixing''' - Too low deforms on emulsion, too high pits, optimal centered at 120F '''Film freshness (film age)''' - Young broadband with milky tendeny, old narrow band and clear tendency '''Room Temp (exposure)''' - Warmer increased sensitivity '''Room Humidity (exposure)''' - More humid increased sensitivity '''Exposure Time''' - Longer harder bluer narrower banded, shorter softer redder broader banded '''Dark reaction time''' - Longer harder bluer narrower banded, shorter softer redder broader banded '''Fixer Time''' - Too short milky soft , too long harder bluer '''Light or heat fixing (if applicable)''' - Low light/heat softer broader banded milky, lots light harder bluer narrow band '''H2O rinse time''' - Too short non clear film '''H2O rinse temperature''' - Hotter broadband, lower narrow band '''IPA concentrations (ratios''') - Faster increase in ratios (35, 100) broadband, slow increase (30, 50, 70, 90, 100) narrower banded, modifying 50% from 35- 50% shifts color towards blue. '''IPA time''' - Shorter broadband, longer narrow band '''IPA temperature''' - Higher broadband, lower narrowband '''Blow drying''' - Too slow uneven blotches, to short degradation of holo over time '''Wavelength''' - The shorter wavlengths the higher sensitive, and will greatly effect the other variables 119bc19e660927aae15b70893617f3f082a94778 0 207 262 261 2013-05-12T02:51:34Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Jeff Blyth has online instructions for making Silver Halide Plates. *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] ===Gelatin Film thickness=== In the case of MBDCG a thinner film can give a bit more sensitivity because you can have more MB dye in. If x % of dye is optimum for a dried film of 10 microns then for a dried film of say 40 microns you need to cut it down to 0.25x% and that is usually bad for sensitivity. If you leave it at x% then you kill too much object beam light. However you can get away with x% if you are able to do split beam reflection work (unlikely you have enough laser power with MBDCG unless you are making say 1 sq cm size images). Single beam transmission H’s could be OK though. ===Silver Halide=== If the diffusion method is tried on coatings much thicker than 7 microns it is troublesome. I have tried it on ~ 100 micron gelatin and decided that it was not viable. The problem being that the rate of diffusion decreases exponentially with time and AgNO3 can carry on diffusing into the thick film and away from the incoming bromide ions . If you leave it long enough (several minutes) for the bromide ions to catch up and combine with the furthest Ag ions near the glass then the front end may have already been in the Br bath too long and you start to get grain growth . If you don’t catch those unreacted Ag ions at the glass end then they quite rapidly develop up in the (ascorbic acid pH 6) sensitizer bath causing bad darkening or bad fog. You can stop this by giving the film a very prolonged soak in tap water (with its Cl- ions) after the Br bath before the sensitizer bath. What you get is then virtually all the silver bromide in the first few microns and none in the gelatin nearer to the glass , you might just as well have coated it thinner in the first place. However using the conventional process with AgBr precipitated in molten gelatin solution you still get fundamental problems if you try to coat ultra thick layers. The processing chemicals take much longer to migrate in and grain growth and unevenness is inevitable. I needed to make some experimental coatings about 1 mm thick and although I got gratings they were sadly dim. I struggled to get any grating at all. Once upon a time, Agfa produced an experimental 8E75’B’ coating that was twice as thick as usual but still only ~ 15 microns . Nobody found they could get a good result from it compared to their standard 7 micron. Jeff ===Hans' Diffusion Post=== As promised, here is a revision of Jeff Blyth's diffusion method that will allow you to make very bright holograms, and some theory as to why I think it works so well. When making your own holographic plates there are two requirements for bright results that work against one another: Lots of AgBr should be in the emulsion, and the AgBr crystals (grains) that are made up from all this AgBr should be as small as possible. It normally is very difficult to make an emulsion that complies to both these requirements and lots of articles have been written up about solving this problem. Lots of methods have been invented, but few are as reliable as Jeff's diffusion method. Why is it so difficult to make small grains: Imagine you have a gelatin solution into which you want to introduce AgBr grains. The traditional method would be to add to this gelatin solution a solution of AgNO3 and a solution of KBr. Both would be added at the same time at a certain rate. This method is called the double jet method. When the addition of the two solutions is started, at first nothing happens. Only the concentrations of both solutions slowly increase in the gelatin solution. Above a certain concentration, suddenly lots of Ag+ ions combine with lots of Br- ions to form very minute AgBr crystals. The formation of these crystals causes a fast decrease in concentration of both the AgNO3 and the KBr. As soon as the concentration drops below a certain value, any added AgNO3 + KBr will not create new grains (as we would like), but cause the grains that are already there to grow. This growing of the grains is not desirable. So, what I mean to say is that for new grains to form, the concentrations of the AgNO3 + KBr need to be above a certain critical value. Concentrations below this value cause grain growth and even lower concentrations do nothing at all. As you can see now the double jet method needs precisely controlled flows of liquids to allow for concentrations to be above this critical nucleation concentration to allow as many micrograins to form. Second problem is that if there are many small grains present, any newly added AgNO3+KBr prefers to settle onto those grains rather than forming new nuclei. And here lies the difficulty in making emulsions with both small grains and lots of grains at the same time. Most of the old recipes for making Lippmann emulsions are for making very fine grain emulsions, but with a very low amount of silver in them. Manufacturers of holographic film usually keep their methods for making their emulsions a secret just because of this reason. Now if there were a method of instant mixing a gelatin emulsion of very high concentration AgNO3 with a liquid of very high concentration of KBr (and very quickly after mixing both the excess AgNO3 and KBr could be removed), very small grains in high quantity would be virtually guaranteed. And this is where Jeff's brilliant diffusion strategy comes to the rescue: Imagine you had a very thin gelatin layer that was soaked with AgNO3 and this would be suddenly dunked into a solution of KBr, the KBr would be introduced to the AgNO3 throughout the surface of the gelatin as it diffuses into the layer. So a great many small grains of AgBr would form instantly everywhere inside the very thin layer of gelatin. If the layer is then quickly washed after this step, all excess AgNO3 and KBr are removed and thus further growing of the grains is no longer possible. This is not the whole story by a long shot though. In normal kitchen gelatin there are often left-over chemicals from the fabrication process that actually encourage grain growth. Any chlorides present in the gelatin would hamper the formation of small grains because AgCl is a lot more soluble than AgBr and also because when the AgNO3 is added to the gelatin, the first nuclei that are formed are AgCl nuclei and that's not what we want because we want the sudden process of virgin AgBr nucleation as the gelatin is dunked into the KBr solution. Any chemicals with Sulfides in them also cause grain growth. Luckily there is a way to clean your gelatin. More about this later. Just like there are chemicals that encourage grain growth, there are also chemicals that discourage grain growth. And that is where the second brilliant idea of Jeff comes to play. It just so happens that the dye used in the diffusion process (pinacyanol chloride) is one of those chemicals that help prevent grain growth. Adding this dye (that makes your emulsion sensitive to red laser light) to the KBr solution will help keep the grains small: as the gelatin is dunked into the KBr, the newly formed grains are quickly coated with dye molecules, preventing further settling of new AgBr onto them. One problem with the dye is that it does not like to be in water. That is why the KBr mixture is actually a mixture of water+methanol. The dye is very soluble of methanol and will stay even in solution if some water is present. Ok, so much for theory. Here is the procedure. Rather than writing up the differences from Jeff's original procedure I will now proceed and type the whole recipe. ====Washing the gelatin==== For this you need a small glass jar. Fill jar with 20ml of de-ionized (DI) water and add about 2.2 gram of gelatin. Next slowly warm this mixture to about 45C until the gelatin is completely dissolved. Take a plastic tupperware and pour this liquid into it and allow it to gel. When the solution has gelled, cut this gel up into small cubes with a plastic knife. Pour about 100ml of cold DI water into the tupperware tray, rock it a little and let it sit for about 30 minutes. (this step allows any contaminants in the gelatin to diffuse into the DI water). Pour off the DI water and add fresh DI water, rock and let it stand 30 minutes again. Repeat this procedure about 4 times. When you're done washing the gelatin, put it back into the glass jar and put it in the fridge (not the freezer) for later use. ====Preparing the glass==== When put into a alkaline developer, gelatin does not want to stick to glass anymore. So the glass needs to be prepared for holographic use. Firstly wash a piece of glass (say 20x30cm) with vinegar (this will remove some of the grease that is on the glass). After that, vigorously rub the glass with household ammonia and be very careful not to get any of this into your eye because it will make you blind forever. Now the glass will be very clean. The next step will be to chemically treat the glass to make it sticky. ====Making the glass sticky for gelatin==== Add about 0.5ml of 3-amino-propyltriethoxysilane (less is better than more) to 100ml of Acetone and rub this solution onto your cleaned glass plate. Let the plate sit for about one hour and then clean it again. This time with a Ammonia based glass cleaner. Your glass has now been coated with a very thin layer of molecules that on one side stick to the glass. The exposed sides of these silane molecules have -NH3+ endings that bond well with the gelatin. ====RainX==== You will need a second glass plate to be able to make a nice gelatin coating. Throughly clean a glass plate of the same size as the plate that was prepared from step [2] and rub it with an automotive anti rain agent such as Rain-X. And then rub it with a clean dry towel. On two opposing edges of this plate stick a long piece of Scotch tape. (During the coating step, gelatin will be poured onto this plate and the silane treated plate will be put on top of this gelatin puddle. The Scotch tape acts as a spacer and allows a perfect gelatin coating with just the right thickness when dried.) ====Preparing the chemicals==== * Mix 1g of pinacyanol chloride in 1000ml of methanol. This solution will last you a life time. * Mix 33ml of water with 66ml of Methanol. To this solution add 6 gram of LiBr and 2.5ml of the dye solution. Pour this liquid into a Tupperware tray that is big enough to hold your glass plate and close it. ====Wear Safety Glasses==== If you get AgNO3 in your eye you will be blind forever.:Take your washed gelatin from the fridge and warm it up to 45C again. When it has become completely liquid again, add 1.2 gram of AgNO3 to this solution. Often the solution becomes milky when you do this, but if you stir for about a minute, it will become transparent again. ====Coating the Plate==== Heat your Silane treated glass plate with a hair drier and while holding it level (USE KITCHEN GLOVES), pour a puddle of your gelatin on top of it. Quickly place the Rain-X treated glass plate on top of it and allow the gelatin to completely spread between the glass plates. After a few minutes the gelatin will gel and both plates will stick together. Now place this sandwich into the fridge and leave it there for a few hours. ====Washing Baths==== When doing the diffusion method it is important to stop the grain growth as soon as the grains are formed. Also it is preferable to remove any excess silver nitrate from the coating as soon as possible. So, prepare two trays of DI water to remove most of the AgNO3 and LiBr that is left over in the gelatin and one tray with tap water (most tap water contains some chloride that will precipitate with whatever Ag+ ions that are left after washing). To the tap water bath you should add a few drops of liquid dishwasher fluid. ====Diffusion Step==== After a few hours remove your glass sandwich from the fridge into your safe lighted room. With a plastic knife remove the Rain-X treated plate from your Silane treated plate. If all went well, the gelatin coating should stick to the Silane treated plate in a perfect smooth coating. Without waiting for the plate to dry or become warm, immediately drop this plate into the LiBr bath and leave it there for about 45 seconds. Then quickly take the plate out and transfer it to the first DI water bath for about 1 minute. Then the second DI water bath, then the tap water bath. Let the plate drip dry by setting it almost vertically against an object on your table. After about 15 minutes when most of the water has dripped from the plate you can use a cool hair drier to finish drying. ====Sensitizing==== Your freshly made plate will not be sensitive enough yet for practical use. Also the gamma of the emulsion will not be suitable yet for holography. Prepare a solution of 100ml water + 1.2 grams of Ascorbic Acid (=vitamin C) + 0.4 gram of NaCO3 + few drops of dishwasher liquid. Immerse your plate into this for about 2 minutes and dry again. When the plate is dry, it is ready for use and to be exposed for the brightest Denisyuk hologram you have ever made. Ok, so that's about it. It looks like a complicated and long procedure. But after you have done it a few times, you will find it easy and simple to do and reasonably fast. It is possible to make a number of plates in one day and store them in the fridge for later use. This procedure addresses a number of problems in the original procedure: * Lots more silver will be present in the gelatin. This will make your holograms a lot brighter. The original recipe calls for first coating the gelatin and afterwards introducing the AgNO3. This can certainly be done, but the gelatin needs to be very very hard and squeegeed well after adding the AgNO3. Otherwise AgNO3 will crystallize on the surface of the gelatin layer and prevent diffusion from taking place. * This method will allow for very soft gelatin layers to be made. This is interesting if you want to experiment in doing SHSG. * In the original method there is also some Ascorbic Acid in the LiBr+dye bath. This certainly does work, but you run the risk of developing out any AgNO3 that has not precipitated out. This causes some darkening of the plate. It is better to do the sensitizing afterwards. ====A SHORTCUT THAT IS ADVISABLE FOR FIRST TESTS==== * This adjustment will allow you to do the diffusion method very fast and still give the same brightness. * Skip steps [1] through [7] * Immerse a PFG-01 plate in a solution of 20% Sodium Thiosulfate (non hardening fixer) until it has become completely transparent. And rinse in DI water and dry. * Prepare a solution of 1 ml DI water + 0.18g AgNO3. * With a laser printer transparency spread a few drops of this solution over the surface of the fixed out plate and squeegie the plate very well. * Start from step 8 in the above procedure. * You have now upgraded your PFG-01 plate to a plate that competes well with the brightest plates in the world. I have done the original method, my adjusted method and the quicker method many times over and they give predictable results but have now switched to a completely different method (using double jet) that I don't want to write about just yet. ====INTERESTING EXPERIMENTS TO TRY==== *Gelatin at low concentration is much easier to coat than the 10% that is required for the above procedure. It would be interesting to try to make your fresh dry gelatin into a very fine powder in a kitchen slurpy mixer. Then load this fine powder in a very cold solution of AgNO3. The solution needs to be cold because otherwise the powder will become a sticky mass. Next run this mix through a coffee filter to drain off excess water+AgNO3. Then pour your LiBr+dye mixture over the powder that is still in the coffee filter (do catch what drips out of the filter because it can be used again). Next pour large amounts of DI water through the filter. If all liquids are rather cold during this procedure the gelatin will not clump up and it just might work. After this procedure you would have holographic gelatin that can dissolved when needed at concentrations of about 2% and coated by just pouring on a horizontal glass plate. I don't know if this procedure would work. But if it does work it would be very nice. I tried it once but made a mistake in the dark and made a mess of it. So I was not able to conclude if it is possible or not. *To coat a layer of 2% gelatin on glass to which some dichromate is added. Then make this layer really hard in an oven and use the shortcut method I wrote about above. The layer should be very smooth and hard enough to allow a good squeegee. I have not tried this, but if it works it will be a lot faster. Well, that's about all I know about the diffusion method. I very much enjoyed using it. Please understand that this is by no means the only way to do the diffusion method. If you want to have a go at it, try it this way first and then experiment with your own idea's. I am sure you will come up with idea's that will improve upon this method. 5fbf90e6847cc2d93b5cf5d99a86c8cdc0a705d4 0 209 266 265 2013-05-12T02:51:35Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:DBattin.jpg]] [http://www.geocities.com/greenpagoda/islandholo1.html Dave's Web Site] IT all started for me in the Museum of Holography, in the late 70s. after making one visit i was hooked for life! Seeing what could be done was unbeleivable..... I then joined as a member and started to read any information i could absorb. Attending college in Boston I found all kinds of new info at the college libaries. Upon graduation from college I headded west, finding work near Los Angles in a large machine shop, I found this very convenient for making tooling for my holographic components. After leaving LA and returning to New York, I continued my holographic studies, and met a fellow holographer, Mark Segal (owner of now defunct Spatial Images International)at this lab we produced a large ammout of DCG holography. A short time later a head hunter contacted me about a job working for company called Farirchild Weston Space and Camera, the job was for an optical engineer, I couldn't wait for the interview! They hired me in a flash! The optics lab was about 2500 sq.ft of total OPTICS! Lenses, mirrors, lasers a gigantic isolation table (20 tons+), I spent the next five years building telephoto lenses ths size of 55 gallon drums and tiny ccd cameras that would fit in matchbox! This is where I really learned about the nature of light and optics. 79317af696e9bf934471b16ba84e245512b76295 0 210 268 267 2013-05-12T02:51:35Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki I have successfully killed bad fogging on Slavich plates (without also killing the photosensitivity) by soaking them for exactly 60 seconds in a solution of; 20g Ferric EDTA and 10 g KBr per litre. (This solution keeps for years.) (Ferric EDTA is ethylenediaminetetraacetic acid ferric sodium salt) What amazed me was that the photosensitivity of the plates did not drop noticeably afterwards without my needing to resensitise them in say 2% ascorbic acid (vitamin C) at pH ~6. ~Jeff Blythe 4ecc0fdfdaf5ca0d4a5e4728a284842d6cb89678 0 211 270 269 2013-05-12T02:51:35Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki from [http://Nobelprize.org www.nobelprize.org] Dennis Gabor – Autobiography [[Image:Gabor.gif]] I was born in Budapest, Hungary, on June 5, 1900, the oldest son of Bertalan Gabor, director of a mining company, and his wife Adrienne. My life-long love of physics started suddenly at the age of 15. I could not wait until I got to the university, I learned the calculus and worked through the textbook of Chwolson, the largest at that time, in the next two years. I remember how fascinated I was by Abbe's theory of the microscope and by Gabriel Lippmann's method of colour photography, which played such a great part in my work, 30 years later. Also, with my late brother George, we built up a little laboratory in our home, where we could repeat most experiments which were modern at that time, such as wireless X-rays and radioactivity. Yet, when I reached university age, I opted for engineering instead of physics. Physics was not yet a profession in Hungary, with a total of half-a-dozen university chairs - and who could have been presumptious enough to aspire to one of these? So I acquired my degrees, (Diploma at the Technische Hochschule Berlin, 1924, Dr-Ing. in 1927), in electrical engineering, though I sneaked over from the TH as often as possible to the University of Berlin, were physics at that time was at its apogee, with Einstein, Planck, Nernst and v. Laue. Though electrical engineering remained my profession, my work was almost always in applied physics. My doctorate work was the development of one of the first high speed cathode ray oscillographs and in the course of this I made the first iron-shrouded magnetic electron lens. In 1927 I joined the Siemens & Halske AG where I made my first of my successful inventions; the high pressure quartz mercury lamp with superheated vapour and the molybdenum tape seal, since used in millions of streeet lamps. This was also my first exercise in serendipity, (the art of looking for something and finding something else), because I was not after a mercury lamp but after a cadmium lamp, and that was not a success. In 1933, when Hitler came to power, I left Germany and after a short period in Hungary went to England. At that time, in 1934, England was still in the depths of the depression, and jobs for foreigners were very difficult. I obtained employment with the British Thomson-Houston Co., Rugby, on an inventor's agreement. The invention was a gas discharge tube with a positive characteristic, which could be operated on the mains. Unfortunately, most of its light emission was in the short ultraviolet, so that it failed to give good efficiency with the available fluorescent powders, but at least it gave me a foothold in the BTH Research Laboratory, where I remained until the end of 1948. The years after the war were the most fruitful. I wrote, among many others, my first papers on communication theory, I developed a system of stereoscopic cinematography, and in the last year, 1948 I carried out the basic experiments in holography, at that time called "wavefront reconstruction". This again was an exercise in serendipity. The original objective was an improved electron microscope, capable of resolving atomic lattices and seeing single atoms. Three year's work, 1950-53, carried out in collaboration with the AEI Research Laboratory in Aldermaston, led to some respectable results, but still far from the goal. We had started 20 years too early. Only in recent years have certain auxiliary techniques developed to the point when electron holography could become a success. On the other hand, optical holography has become a world success after the invention and introduction of the laser, and acoustical holography has now also made a promising start. On January 1, 1949 I joined the Imperial College of Science & Technology in London, first as a Reader in Electronics, later as Professor of Applied Electron Physics, until my retirement in 1967. This was a happy time. With my young doctorands as collaborators I attacked many problems, almost always difficult ones. The first was the elucidation of Langmuirs Paradox, the inexplicably intense apparent electron interaction, in low pressure mercury arcs. The explanation was that the electrons exchanged energy not with one another, by collisions, but by interaction with an oscillating boundary layer at the wall of the discharge vessel. We made also a Wilson cloud chamber, in which the velocity of particles became measurable by impressing on them a high frequency, critical field, which produced time marks on the paths, at the points of maximum ionisation. Other developments were: a holographic microscope, a new electron-velocity spectroscope an analogue computer which was a universal, non-linear "learning" predictor, recognizer and simulator of time series, a flat thin colour television tube, and a new type of thermionic converter. Theoretical work included communication theory, plasma theory, magnetron theory and I spent several years on a scheme of fusion, in which a critical high temperature plasma would have been established by a 1000 ampere space charge-compensated ion beam, fast enough to run over the many unstable modes which arise during its formation. Fortunately the theory showed that at least one unstable mode always remained, so that no money had to be spent on its development. After my retirement in 1967 I remained connected with the Imperial College as a Senior Research Fellow and I became Staff Scientist of CBS Laboratories, Stamford, Conn. where I have collaborated with the President, my life-long friend, Dr. Peter C. Goldmark in many new schemes of communication and display. This kept me happily occupied as an inventor, but meanwhile, ever since 1958, I have spent much time on a new interest; the future of our industrial civilisation. I became more and more convinced that a serious mismatch has developed between technology and our social institutions, and that inventive minds ought to consider social inventions as their first priority. This conviction has found expression in three books, Inventing the Future, 1963, Innovations, 1970, and The Mature Society, 1972. Though I still have much unfinished technological work on my hands, I consider this as my first priority in my remaining years. Honours Fellow of the Royal Society, 1956. Hon. Member of the Hungarian Academy of Sciences, 1964. D.Sc. Univ. of London, 1964, Hon. D.Sc. Univ. of Southampton, 1970, and Technological University Delft, 1971. Thomas Young Medal of Physical Society London, 1967. Cristoforo Colombo Prize of Int. Inst. Communications, Genoa, 1967. Albert Michelson Medal of The Franklin Institute, Philadelphia, 1968. Rumford Medal of the Royal Society, 1968. Medal of Honor of the Institution of Electrical and Electronic Engineers,1970. Prix Holweck of the French Physical Society, 1971. Commander of the Order of the British Empire, 1970. Married since 1936 to Marjorie Louise, daughter of Joseph Kennard Butler and Louise Butler of Rugby. From Les Prix Nobel en 1971, Editor Wilhelm Odelberg, [Nobel Foundation], Stockholm, 1972 This autobiography/biography was written at the time of the award and later published in the book series Les Prix Nobel/Nobel Lectures. The information is sometimes updated with an addendum submitted by the Laureate. To cite this document, always state the source as shown above. Dennis Gabor died on February 8, 1979. da0bbce15e2113daaa6ef128352e50f0980f1522 0 212 272 271 2013-05-12T02:51:36Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Dichromated Gelatin (DCG) is one of the brightest media for recording holograms. It is used in art as well as [[HOE]] fabrication. [[A Beginners Approach to DCG]] by John Pecora [[A Simple DCG Recipe]] [[G307 DCG Formula]] Increased overall sensitivity and to 514nm - 532nm [[MBDCG]] [[DCG Theory]] [[Sealing DCG Holograms]] [[The Mechanics of Gelatin and the DCG Process]] [[DCG Variables]] [[Coating Methods]] [[Troubleshooting DCG]] 151638f01f328b547127e6f3311d0750a3661be9 0 213 274 273 2013-05-12T02:51:36Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki (For details and setup examples, see the [[Holography_Technology]] page.) (For a more technical description see [[Holograms]].) ===Comparison=== ===Single Beam Reflection=== Also called a Denisyuk Hologram this is the most common first hologram. It is fairly easy to set up and can be viewed in white light. This type of hologram is one of the least expensive as there are minimal optics and the stability requirement can be minimized by touching the plate to the object. ===Single Beam Transmission=== This is actually easier than a Single Beam Reflection however since it requires a laser for viewing it is not as common. The depth of field shown is often much better. This type of hologram is one of the least expensive as there are minimal optics and the stability requirements can be minimized. ===Split Beam Reflection=== This hologram is also known as an off-axis reflection hologram, or a "straight reflection" hologram. The laser beam is split into two beams with an partially mirrored beamsplitter, which can be mounted on a variable slide. One portion of the divided beam is spread with lenses or diffusion glass to illuminate the object, set in front of the holographic recording medium. The other portion of the laser is spread through a lens array or spacial filter, then reflected off of a collimating mirror, which is directed at the back of the hologram-to-be at the reference angle. The reference angle is determined by: practicality in the optical set-up; Bragg's angle and the frequency of the recording laser; and the angle of the intended viewing light; with a range of 38 to 46 degrees giving good interference fringes. The reference angle will become the illumination angle of view for the finished hologram. Steering mirrors are needed to complete this set-up. This type of hologram can be more expensive to produce as there are additional optics needed and more stringent stability requirements. It can be much brighter than a Single Beam Reflection. It can also contain relatively vast parallax. Depth is limited as in a Denisyuk hologram. (Image plane reflection holograms offer greater depth and projection possibilities, but their parallax potential is not as great as in a straight reflection hologram) ===Split Beam Transmission=== This is the most common way to make a transmission hologram. It requires a beamsplitter and is most often used to make an H1 for copying. This type of hologram is going to be more expensive as there are additional optics needed and more stringent stability requirements. ===H1 to H2 Copies=== This is making a copy of a hologram. It is a more complicated set up requiring a beamsplitter and a good Master Hologram (H1). It allows the hologram to bisect the film plane with some of the scene in front of the plate and some behind. ===Rainbow Transmission=== This is a special case of an H2 copy. It is a transmission hologram made by masking the master hologram (H1) to a horizonantal slit. It is viewable in white light but the color changes with viewing position. ===Multiplex=== This is a very complicated set-up and has to do with storing many close views or perspectives of an object onto a single holographic plate in the form of slits. Then those slits are imaged to the same relative location in space creating a focused, multi perspective image. A hologram is then made of the combined image projections creating 3 Dimension hologram. ===Holographic Optical Element (HOE)=== [[HOE]]s are holograms that work like optical elements (mirrors and lenses). ===Computer Generated=== By computing the interference patterns, it's possible to simulate a hologram in software. The result when printed to a transparency using a standard printer is usually low resolution and inefficient, but can work. [http://www.medcosm.com/prog_CGHmaker.htm MedCosm CGH Software (free)] 72613e8c79569859dab05e20926dd67cf1212570 0 214 276 275 2013-05-12T02:51:36Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Diffusers can be used to soften the shadows from the object beam for softer lighting effects. From a artistic lighting standpoint, a laser is considered a point source. To make softer lighting we need to widen the beam source. There are many ways to do this: *Broken Light Bulbs *Sandblasted Glass *Etched Glass *Glass or Plastic sanded in one direction only Commercial diffusers are also available. You can specify how much diffusion you need. A 10% diffuser allows most of the light to pass through. A 30% diffuser spreads more of the light. It should be remembered the diffusers also randomize the polarization. This can increase the fog level of the hologram. It is very important the the diffuser be shielded from the plate so no stray light can hit the plate directly. ae42fed899c7a48d9ebc34c466c95c78475e8965 0 215 278 277 2013-05-12T02:51:37Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 216 280 279 2013-05-12T02:51:37Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Here is a [http://rudieberkhout.home.mindspring.com/SPIE-Acompactdisplay.htm Great Article] by [[Rudie Berkhout]]. 2dc1ff8bef87677ee63899438d74c914cfdfcd7e 0 217 282 281 2013-05-12T02:51:37Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [http://www.vilamedia.com/ VilaMedia's Web Site] 6d589f6d169cc09c6f5b9b6de0975f261ebfecb1 0 218 284 283 2013-05-12T02:51:37Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [http://www.integraf.com Integraf] Dr. Tung H. Jeong (better known as "T.J.") is a professor emeritus at Lake Forest College, Lake Forest, Illinois, and has over 35 years of experience in holography. He has led the field of holography as researcher, innovator, consultant, and, most significantly, educator. Having authored numerous articles, T.J. is recognized as a leading scholar in holography. TJ's recent publications include an article published in Applied Optics, the most widely read international holography journal. Besides research, T.J. has also produced two motion pictures. One entitled, "Introduction to Holography," was sponsored and marketed by Encyclopedia Britannica. A teacher at heart, T.J. has been invited to lecture and teach seminars at over 500 universities, professional societies, and industrial sites in Europe, China, Russia, among other international locations. T.J. has also co-chaired international conferences on holography and optics in Russia, Bulgaria, and Hungary. Moreover, for nearly 30 consecutive years, T.J. has hosted holography workshops for novices and experts. In 1982, T.J. started the triennial International Symposium on Display Holography. His most recent symposium attracted over 120 scientists, artists, and businessmen from 18 countries. Together with Dr. Hans Bjelkhagen, a visiting scientist from Sweden, T.J. discovered technology that makes true-color holograms possible. T.J. is also credited with the discovery of cylindrical holograms, changing holograms from flat formats into images people could walk around and view from all perspectives. In 1973, T.J. shared in the development of the technology that created three-dimensional moving holograms and was the first to implement the use of optic fibers, making holograms simpler and less costly to make. In the business world, T.J. serves as a worldwide consultant to corporations in various industries to develop holographic solutions. For example, T.J. has worked extensively with DuPont on their development of holographic photopolymers. With the development of this technology, holograms is becoming a common part of people's lives. (Photo: Encyclopaedia Britannica Educational Corp., 1972) T.J. joined the faculty of Lake Forest College in 1963 and served as director of the Center for Photonics Studies. He came to the U.S. from China as a young boy in 1948. Upon graduation from Amarillo High School in Texas, he attended Yale University under a full-scholarship, and received his B.S. degree in physics and mathematics in 1957. He completed his Ph.D. degree in nuclear physics at the University of Minnesota in 1963. A member of many professional societies, T.J. is a Fellow of the Optical Society of America and the recipient of the Robert Millikan Medal from the American Association of Physics Teachers. He is also recipient, of the Saxby Medal of the Royal Photographic Society of Great Britain and the Lifetime Achievement Award from the International Holographic Manufacturer's Association. T.J. has regularly chaired of the annual conference Practical Holography - Materials and Applications, sponsored by the International Society of Optical Engineering (SPIE) and the Society for Imaging Science and Technology (IS&T), taking place in San Jose, California. In November 2005, T.J. was a keynote speaker at the Holopack Holoprint international conference in Shenzhen, China. 97b7ea478b7f0878f6b1fdfbcc8be43f4ea6a0b0 0 219 286 285 2013-05-12T02:51:37Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==Drilling a hole in a drill press== *Layout the position of a hole with a scribe. *Mark the exact hole position with a punch. *Drill large holes by predrilling a hole matching the diameter of the web of the drill bit. *Choose the correct speed for the size hole and the material being drilled. *When in doubt use slow speeds and strong feeds. *Smaller holes require quicker speeds and lighter feeds. *Back holes in soft materials with another piece of material to prevent "Blowout". ==Seting up a drill press== *There shold be only the smallest amount of play when trying to move the chuck back and forth by hand. *Make sure when drilling through work that the drill bit can not come in contact with the table. *Use a piece of 1/2" drill rod in the chuck with a square to measure the table for squareness. *Setup holes so the minimum amount of quill extention is required for drilling a hole. ==Speeds and Feeds== *Steel *Aluminium *Soft Wood *Hard Wood ==Safety== *Never leave the key in the chuck wihile changing drill bits. *Never wear gloves while holding work in a drill press. *Always try to hold down work by bolting it to the table or by using a vise. *Always usy eye protection when using a drill press. *Unplug or remove the dafety key when chaning drill bits. *Never allow the chip fromed by drilling a hole to grow larger than 1 inch. If the chip starts to become a string relax pressure on the feed until the chip breaks off. 8942021b2424387fca466042bac1ea6493cbe919 0 220 288 287 2013-05-12T02:51:38Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Eberhard effect''' - border effect occurring in a developed image. It appears as a dense line along an edge of high density and as a light line along an edge of low density. It occurs most often in plates developed flat in solution that is not sufficiently agitated. The effect was described by Gistav Eberhard in 1926. *'''Electrophotography''' - creation of images by alteration to the electrical properties of the sensitive material as a result of the action of light. *'''Elon''' - another term for Methylaminophenol sulfate. It is more commonly known as metol. *'''Emulsion''' - light sensitive material which consists of a suspension of silver halides in gelatin. *'''Endoscope''' - optical device allowing the viewing and photography of small inaccessible subjects. *'''Evenescent Wave''' - "Tending to Vanish" - A wave whose intensity decays as an exponetial of distance. (As opposed to sinsusoidally.) *'''Exposure latitude''' - amount by which it is possible to over or underexpose a light sensitive material and, with standard processing, still produce acceptable results. a26eede8a1e43a4d73ca02e8c53edc87d5ffaac8 0 222 292 291 2013-05-12T02:51:38Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:Edwesley.jpg]] Ed Wesly Ruby Pulsed Hologram - Fermilab PROFESSIONAL OBJECTIVE: To continue to share my wealth of knowledge and experience with more students in the fields of lasers, optics, holography and photography. TEACHING EXPERIENCE: Full-Time Faculty, Harrington College of Design, teaching Physics of Light (Optics), Photo-History, and College Math in the Digital Photography Department, January 2005 to present. Adjunct Assistant Professor, teaching a variety of classes in the Art and Technology and Liberal Arts Departments at the School of the Art Institute of Chicago, including the Beginning and Intermediate/Advanced Holography Studio, Optics for Artists, 3-D Hard Copy, and The Physics of Everyday Objects, January 1986 to present, with a couple of hiatuses. Instructor, Columbia College, Chicago, for the courses, "The Physics of Lasers, Holograms, and Modern Optics", "Photographic Theory/Laboratory Practice for Cinematographers", and "Imaging Optics", February 1985 to June 1997. Teacher, Cicero School, Cicero, IL, 7th and 8th grade Math Classes, September 1981 to June 1982. Director of Education for the Fine Arts Research and Holographic Center, Chicago, IL, June 1980 to May 1981. Teacher, Hardey Preparatory School, Chicago, 6th, 7th, and 8th grade Math Classes, September 1977 to June 1980. TECHNICAL EXPERIENCE: Production Holographer, CFC International, Countryside, IL, laboratory technician preparing holographic images for mass production, October 1998 to November 2004. Sales Engineer, BEA electro-optics, Des Plaines, IL, manufacturer's representative for a variety of electro-optical companies, June 1997 to October 1998. Research Associate at Lake Forest College, Lake Forest, IL, supported by a grant from a manufacturer of medical equipment to test the feasibility of replacing conventional optics in some of their equipment with Holographic Optical Elements, October 1987 to February 1993. Holographic Engineer for Northwestern University, Evanston, IL, researching holographic endoscopes using Ruby laser light piped through fiber optics, May 1986 to May 1987. Holographic Engineer for Holicon Corporation, Evanston, IL, setting up a studio to record holographic portraits using a Ruby laser, May 1986 to May 1987. Holographer for the 15 foot Bubble Chamber at Fermilab, Batavia, IL. Part of a team using a Ruby laser to make holograms of atomic particle tracks, March 1985 to April 1986. Optical Engineer for Magnaflux Corporation, Chicago, IL. Designed and built an 8 by 8 foot isolation table equipped with an Argon laser for real time interferometry of large objects, October 1983 to September 1984. EDUCATIONAL BACKGROUND: University of Illinois at Urbana, Bachelor's of Science Degree in the Teaching of Mathematics, January 1976. PROFESSIONAL ORGANIZATIONS: Member of the Optical Society of America, (OSA), and the Society of Photo-Instrumentation Engineers (SPIE). Councillor for Chicago Chapter of SPIE/Optical Society of Chicago Featured Speaker at the June, 1997 meeting of the Optical Society of Chicago. PUBLICATIONS TEXTBOOKS (self-published): INSTRUCTION MANUAL FOR THE HOLOGRAPHY STUDIO AT SAIC, September 1995 OPTICS FOR ARTISTS, September 1995 (e-version on-line Fall 2003) PHOTOGRAPHIC THEORY/LABORATORY PRACTICE For Cinematographers, September 1995 IMAGING OPTICS, February 1996 VIDEOS: "Ruby Laser Guts", 1996, and "Gaseous Lasers", 1996 SELECTED ARTICLES: "Inside-Out Engineering: Characterizing the Holographic Stereogram Printer at The School of the Art Institute of Chicago", Proceedings of the SPIE, 1997. "A Toast to Nick Phillips", Leonardo, Volume X, Number 3, 1992. "A Proposal for a National Space Monument", Proceedings of the SPIE, Vol. 1600, 1991. "Holography of Particle Tracks in the Fermilab 15-Foot Bubble Chamber," with W. Smart et al., Nuclear Instruments and Methods in Physics Research A297, 1990, p.364-389. "Teaching Holography in an Art School Environment," Proceedings of the SPIE, Vol. 1396, 1990. "Progress in True Color Holography", with T. Jeong, Proceedings of the SPIE, Vol. 1211, 1990. "Recycling Holographic Plates", Proceedings of the Third International Symposium on Display Holography, Lake Forest College, 1988. "Exploring Personal Holography", Darkroom and Creative Camera Techniques, Nov/Dec. 1986. "Seven Single Beam Projects", Proceedings of the Second International Symposium on Display Holography, Lake Forest College, 1985. Technical Editor for holosphere, the Advocate of Holographic Art, Science, and Technology, 1985 to 1991. REFERENCES: Dr. Tung Jeong, emeritus, Lake Forest College, Lake Forest, IL (Tjeong@aol.com) Dr. Hans Bjelkhagen, DeMontfort University, Leicester, England (Hansholo@aol.com) Dr. Manfred Stelter, PTI, Oak Creek, WI (pti@execpc.com) Dr. Gerald Cohn, Cyber-Tech, Evanston, IL (cybertek@megsinet.net) Dr. Elizabeth Wright, School of the Art Institute of Chicago, Chicago, IL (ewright@artic.edu) Dr. Pan Papacosta, Columbia College, Chicago, IL EXHIBITIONS: GROUP SHOWS Untitled, Richard Hunt Art Center, Benton Harbor Michigan, November 1996. Candy for the Eyes, Mind and Sol Gallery, Chicago, IL, September 1995. Unknown Chicago, Gallery 312, Chicago, IL, July 1995. The Fourth International Exhibition of Display Holography, Lake Forest College, July 1991. Matter Over Mind Sculpture Conference, Fermilab, Batavia, IL, May 1991. Diorama Wonderama, Gallery 836, Chicago, IL, November 1990. L.A.S.E.R. Members Show, Holos Gallery, San Francisco, CA, Summer 1990. New Media, New Directions, Northern Indiana Arts Association, Munster, IN, August, 1990. International Congress on Art in Holography, May - July 1990. The One-Liner Show, Gallery F-XU, Chicago, IL, February 1990. Visual Perceptions: Color, Light and Space, Gallery of Design of the Merchandise Mart, Chicago, IL, February 1989. The Third International Exhibition of Display Holography, Lake Forest College, July 1988. Visions in Light, Museum of Holography, Summer 1988. Images in Time and Space, Montreal, Canada, May 1987 to June 1989. The Holographic Instant: Pulse Laser Holograms, at the Museum of Holography, New York, May to October 1987. A.I.R. Waves at the Museum of Holography, New York, January to May 1987. 2 X 2 Show at the School of the Art Institute of Chicago, May 1986. Holography Group Show at the Limelight, Chicago, February 1986. Holography Exhibition at the School of the Art Institute of Chicago, November 1985. The Second International Exhibition of Display Holography, Lake Forest College, July 1985. New Light, Chicago Public Library Cultural Center, July 1984. The Connie Show, W.P.A. Gallery, Chicago, IL, April 1984. Stare Magazine Fifth Anniversary Show, at Word City, Chicago, June 1982. Post-Mortem Moderne, at the House o' Beauty, Chicago, IL, July 1980. First Contact, Chicago, IL, February, 1979. Illinois Photographers' Lottery, De Kalb, IL, May, 1978. EXHIBITIONS: ONE MAN SHOWS Down in the Basement, Artigliography, Indianapolis, IN, September - October, 1990. Doodles, Atlanta Gallery of Holography, Atlanta, GA, April 1990 Recent Pulsed Stuff and Other Delights at Benny's CASINO, Chicago IL, August 1986. AWARDS: Artist in Residence Direct Grant, from the Museum of Holography, New York, October 1984. Participant in the International Congress on Art in Holography, St. Mary's College, South Bend, IN, July 1990. COLLECTIONS: Global Images, Vancouver, British Columbia, Canada. Museum of Holography Collection, MIT Museum, Cambridge, MS. Dimensional Imaging Consultants, Niles, MI. Hans Bjelkhagen, Leicester, England 0c1e24f97d4b1a7f71c759f8f0b647ef523acaf8 0 223 294 293 2013-05-12T02:51:39Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:B3logo.jpg]] 2D/3D Hologram directed by Colin Kaminski An embossed hologram is a rainbow transmission hologram with a mirror (aluminized layer) laminated to the back. Much like the traditional vinyl record printing process, the pattern is embossed by heat and pressure from a metal stamp onto a thermoplastic medium. There are many types of embossed holograms. '''2D Embossed Holograms''' are made from two dimensional artwork, usually a transparency. '''2D/3D Embossed Holograms''' are made from a stack of two dimensional artworks so each layer is a different distance from the film plane. '''3D Embossed Holograms''' are made from three dimensional models. '''Multiplexed Embossed Holograms''' are made from many pieces of artwork, often from a LCD screen. Once the original artwork is ready, a transmission master hologram (H1) is made, usually with Silver Halide holographic film or plates. The H1 is a slit hologram which will provide the geometry for a Rainbow copy. This Slit is then used to make a Rainbow transmission hologram (H2) into Photoresist. The H2 is processed with an etching solution so that the recorded fringes become a relief pattern of grooves on the hologram surface. The Resist is then silverized, which preserves the relief pattern while alowing the surface of the hologram to be electrically conductive. This silverized hologram is then placed in an electroforming tank and nickel plated, becoming a Mother Shim. The Mother Shim is peeled off, rejigged, placed back into an electroforming tank and another shim is grown on top of the Mother shim which becomes the Child shim. Many Child shims can be made from one Mother shim. The Child shim is placed in a Holographic Printer or embossing machine. Using heat and pressure the releif pattern on the shim is pressed against thermoplastic and the pattern is transferred to the plastic. shown at the top of the page. As many thousands of stampings can be made from one Child shim and quite a few Child shims can be made from one Mother shim, it is very possbile to make hundreds of thousands of embossed images from one Mother Shim. '''Security Holograms''' Because holograms are impossible to make without a giant laboratory and millions of dollars, they are often used for security purposes. You probably have one on the credit card in your wallet. Feel more secure? '''Making Embossed Holograms''' There are a number of steps required to make embossed holograms. Thus the costs are quite high for the first embossed hologram but as the processes allows 100's of thousands of hologram to be stamped in plastic, the costs per hologram gets reduced to pennies with the increase in the number of holograms wanted. First artwork needs to be made. This can be a 3D model, some 2D litho "pictures" or computer generated artwork. The artwork needs to be rather shallow in depth because the nature of the embossed process requires the hologram to be a surface relief hologram utilizing only the fringes on the surface of the hologram. A special kind of transmission master needs to be made from this artwork. It is called a slit master (H1) or rainbow transmission master hologram and can consist of more then one slit. For a final embossed rainbow hologram that has the foreground or object roll through the rainbow colors while the background rolls through different colors (shifted) at the same time, two slits can be made on the same plate separated by the color shift distance. Most of the time this H1 is made in silver halide. Once the transmission master (H1) is made a transmission copy (H2) is made from the H1 master. If there are two slits on the master they can both be imaged onto the H2 copy with one exposure. This is usually done on photoresist. Photoresist is most sensitive to the UV but is less sensitive to the deep blues and blue lines. The HeCd laser is most used for this exposure but the 457 line of and Argon Ion can be used. Exposure times of 30 or more minutes are not uncommon. Once the resist copy rainbow hologram is made, it is put in an etching solution that etches away the areas that have not been exposed to light (the destructive interference parts of the fringes) and leaves the exposed regions of the fringes (there are some etching solutions that work opposite and remove the exposed parts and leave the unexposed parts). The hologram can now be seen in on the resist. The resist is then covered with an electrically conductive layer, usually silver. A two part silverizing process used to make mirrors can be adapted to use for this process. It is important to maintain the surface relief structure of the fringes so a process that lays down an atom at a time is necessary. To simply coat the resist with silver would "level" out the fringes. The silverized hologram is then placed in an electroforming tank and a layer of nickel is deposited (grown) onto the silverized hologram. This is called the mother nickel shim. The mother nickel shim is then peeled away from the resist which degrades and destroys the resist which is no longer any good. The mother nickel shim is placed back in the electroforming tank and another layer of nickel is deposited onto the mother shim. This layer is then peeled off mother shim and is called the daughter shim. Many daughter shims can be made from a single mother shim by reintroducing the mother shim back into the electroforming tank and growing a subsequent daughter shim from it. The daughter shim is then placed into an embossing printer which "stamps" the relief fringes maintained in the shim onto the surface of a plastic film using heat and pressure. This printer can print out hundreds of hologram per minute. After thousands of holograms are stamped from a single daughter shim the daughter shim starts to degrade. The printer can then be loaded with another daughter shim and the process can continue. As the final hologram is a transmission hologram a reflective backing, usually Mylar, needs to be present such that the light can pass through the hologram, reflect off the backing and illuminate the embossed hologram from the back. The reflective backing can be part of the original stock plastic that passes through the printer or added during or after the embossing process. Also, other qualities like an adhesive backing can also be accommodated for with the stock plastic material. As you can see, it is quite elaborate to make the first embossed hologram but after thousands, the cost can be reduced 10,000 to 100,000 fold. It is not uncommon to see mass produced embossed holograms retail sell for $0.05 (US) a piece. fcfd998a2ccdc195a617315504c684a030087f41 0 224 296 295 2013-05-12T02:51:39Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Emmett Leith (born in Detroit, Michigan, died December 23, 2005) was a professor of electrical engineering at the University of Michigan and the inventor of three-dimensional holography. Leith was educated at Wayne State University. Professor Leith and his coworker Juris Upatnieks displayed the world's first three-dimensional hologram at a conference of the Optical Society of America in 1964. In 1979, President Jimmy Carter awarded Leith with the National Medal of Science for his research. [http://en.wikipedia.org/wiki/Emmett_Leith Wikipedia] b09d470ab056dffbfb13e4eebf9958fb02e01398 0 225 298 297 2013-05-12T02:51:39Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Epoxy is different from most glues in that it is a mechanical bond. It will bond to most rough surfaces. To glue metal first sand with 80 grit then wash with acetone. ==Mixing Epoxy== Epoxy is a two part glue. There is a resin and a hardener. It is very important to have an even mixing between the two parts. For very small amounts mixing with a plastic stick on a piece of wax paper or plexiglass works well. Avoid using wood as it can absorb the chemicals differentially. Scrape the entire amount of glue off the mixing pallet often and mix to insure the epoxy nearest the pallet gets mixed in. For slightly larger amounts a paper Dixie cup works well. Make sure to scrape the sides and the bottom while mixing. 45 seconds of stirring and 15 seconds of scraping is a good rule of thumb. For very large amounts there are drill attachments and instructions are included with their purchase. For large amounts it is good to use a respirator. ==Calculating Epoxy Needed for a Fabric Layup== -from West Systems This formula will help you estimate the amount of mixed epoxy needed to wet out fiberglass cloth (assuming a resin-to-fiber ratio of 50:50) and apply three rolled epoxy coats to fill the weave of the cloth, i.e. "fill coats." The formula includes a waste factor of approximately 15%; however, more (or less) may be needed depending on the job and personal application technique. The epoxy is applied at standard room temperature, approximately 72° F. Gallons of mixed epoxy=A×[(Wf×0.00085)+0.0075] Where: A=Total area covered by fiberglass. Units are in square feet (ft^2) Wf =Total weight (W) per square yard of fiberglass (f) cloth used in laminate. Units are in ounces per square yard (oz/yd^2), i.e. 6 oz fiberglass cloth weighs 6 oz/yd^2. [http://www.crosslinktech.com/calculationaids.htm Epoxy Mixing Calculations] 0f28565ccfb06b1040a280db0e56a913fc2b1ae8 0 226 300 299 2013-05-12T02:51:39Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki There is a great deal of equipment available for use in holography. While a hologram can be made with very simple equipment, many holographers have $1000s invested into there labs. The most important piece of equipment is the [[Laser]]. It privides the coherent light source required for making a hologram. In order to steer and shape the beam holographers use [[Mirror]]s, [[Lens]]es and [[Diffuser]]s. More advanced holography is done with 'split beams'. This involves taking the laser beam in splitting it into two or more beams with a [[Beam Splitter]]. A hologram is recorded on a medium. [[Silver Halide Film]] and [[Dichromated Gelatin Chemistry]] are the most common mediums for amature holographers and art holographs. Comercial holograms are usually [[Embossed Holograms]] or [[Polymer Film and Processes]]. Other exotic materials can record a holographic image. See [[Hologram Recording Materials]]. The stability of film is of the upmost importance to recording a hologram. [[Film Holder]]s are designed to hold film stable to 1/2 wavelength of light for the entire exposure time (or better). The polarization of a laser beam can be rotated with a [[Wave Plate]] and this can be quite useful in a large set up. Every optic will contribute noise to the laser beam. [[Optics Aberrations]], dust and fingerprints will leave a mark on the beam quality. In order to clean the beam a [[Spatial Filter]] is used. All of the optics past the first [[Beam Splitter]] need to be held perfectly still. This is acoumplished by designing a [[Optical Bench]] and [[Optic Mounts]] that are very rigid and have no resonances. The exposure time is calculated by using a [[Light Meter]]. Also the ratio of reference to object beam is measured with a [[Light Meter]]. In order to adjust the exposure energy a [[Shutter]] is used to turn the beam on and off. A [[shutter]] can be as simple as a black card removed from the beam by hand or a computer controlled device ===Fringe Lockers=== [[Fringe Locker]]s ===Beam Blocking=== [[Beam Blocker]]s ===Neutral Density Filter=== [[Neutral Density Filter]] 8c591686f5667a7ecebc5208297a21d7f5bec95c 0 227 302 301 2013-05-12T02:51:47Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki An etalon is a optical devise inserted into a laser cavity in order to extend the coherence length. It works by selecting a single frequency of the cavity and only allowing it to propegate. The other modes present are extiguished. :'''''Etalon''' redirects here. '''Etalon''' is also the French word for [[stallion]].'' In optics, a '''Fabry-Pérot interferometer''' or '''etalon''' is typically made of a transparent plate with two reflecting surfaces, or two parallel highly-reflecting mirrors. (Technically the former is an etalon and the latter is an interferometer, but the terminology is often used inconsistently.) Its transmission spectrum as a function of wavelength exhibits peaks of large transmission corresponding to resonances of the etalon. It is named after Charles Fabry and Alfred Pérot. 'Etalon' is from the French ''étalon'', meaning 'measuring gauge' or 'standard' [http://www.allwords.com/word-etalon.html]. Etalons are widely used in telecommunications, lasers and spectroscopy for controlling and measuring the wavelength of light. Recent advances in fabrication technique allow the creation of very precise tunable Fabry-Pérot interferometers. Fabry-Pérot interferometers also form the most common type of optical cavity used in laser construction. Telecommunications networks employing wavelength division multiplexing have add-drop multiplexers with banks of miniature tuned fused silica or diamond etalons. These are small iridescent cubes about 2&nbsp;mm on a side, mounted in small high-precision racks. The materials are chosen to maintain stable mirror-to-mirror distances, and to keep stable frequencies even when the temperature varies. Diamond is preferred because it has greater heat conduction and still has a low coefficient of expansion. In 2005, some telecommunications equipment companies began using solid etalons that are themselves optical fibers. This eliminates most mounting, alignment and cooling difficulties. == Theory == [[Image:Etalon-1.png|frame|right|A Fabry-Pérot etalon. Light enters the etalon and undergoes multiple internal reflections.]] The varying transmission function of an etalon is caused by interference between the multiple reflections of light between the two reflecting surfaces. Constructive interference occurs if the transmitted beams are in phase, and this corresponds to a high-transmission peak of the etalon. If the transmitted beams are out-of-phase, destructive interference occurs and this corresponds to a transmission minimum. Whether the multiply-reflected beams are in-phase or not, depends on the wavelength (&lambda;) of the light, the angle the light travels through the etalon (&theta;), the thickness of the etalon (''l'') and the refractive index of the material between the reflecting surfaces (''n''). The phase difference between each succeeding reflection is given by &delta;: :<math>\delta = \left( \frac{2 \pi}{\lambda} \right) 2 n l \cos\theta. </math> [[Image:Etalon-2.png|frame|right|The transmission of an etalon as a function of wavelength. A high-finesse etalon (red line) shows sharper peaks and lower transmission minima than a low-finesse etalon (blue).]] If both surfaces have a reflection coefficient ''R'', the transmission function of the etalon is given by: :<math>T_e = \frac{(1-R)^2}{1+R^2-2R\cos(\delta)}</math> Maximum transmission (''T''_e = 1) occurs when the optical path-length difference (2''nl'' cos ''&theta;'') between each transmitted beam is an integer multiple of the wavelength. In the absence of absorption, the reflectivity of the etalon ''R''_e is the complement of the transmission, such that ''T''_e + ''R''_e = 1. The maximum reflectivity is given by: :<math>R_{max} = \frac {4R}{(1+R)^2} </math> and this occurs when the path-length difference is equal to half an odd multiple of the wavelength. [[Image:etalon-finesse-vs-reflectivity-2.png|thumb|400px|right|Finesse as a function of reflectivity. Very high finesse factors require highly reflective mirrors.]] The wavelength separation between adjacent transmission peaks is called the free spectral range (FSR) of the etalon, &Delta;&lambda;, and is given by: :<math>\Delta\lambda = \frac{ \lambda_0^2}{2nl \cos\theta } </math> where &lambda;₀ is the central wavelength of the nearest transmission peak. The FSR is related to the full-width half-maximum, &delta;&lambda;, of any one transmission band by a quantity known as the finesse: :<math> \mathcal{F} = \frac{\Delta\lambda}{\delta\lambda}=\frac{\pi}{2 \arcsin(1/\sqrt F)}</math>, where <math> F\equiv \frac{4R}{{(1-R)^2}}</math> is the ''coefficient of finesse''. This is commonly approximated (for ''R'' > 0.5) by :<math> \mathcal{F} \approx \frac{\pi \sqrt{F}}{2}=\frac{\pi R^{1/2} }{(1-R)} </math> Etalons with high finesse show sharper transmission peaks with lower minimum transmission coefficients. A Fabry-Pérot interferometer differs from a Fabry-Pérot etalon in the fact that the distance ''l'' between the plates can be tuned in order to change the wavelengths at which transmission peaks occur. Due to the angle dependence of the transmission, the peaks can also be shifted by rotating the etalon with respect to the beam. === Detailed analysis === [[Image:Fabry Perot Diagram1.png|320px|right]] Two beams are shown in the diagram at the right, one of which (<math>T_0</math>) is transmitted through the etalon, and the other of which (<math>T_1</math>) is reflected twice before being transmitted. At each reflection, the amplitude is reduced by <math>\sqrt{R}</math> and the phase is shifted by <math>\pi</math>, while at each transmission through an interface the amplitude is reduced by <math>\sqrt{T}</math>. Assuming no absorption, we have by conservation of energy <math>T+R=1</math>. Define ''n'' as the index of refraction inside the etalon, and <math>n_0</math> as the index of refraction outside the etalon. Using phasors to represent the amplitude of the radiation, let's suppose that the amplitude at point <math>a</math> is unity. The amplitude at point <math>b</math> will then be :<math>T_0=T\,e^{ikl/\cos\theta}</math> where <math>k=2\pi/\lambda</math> is the wave number inside the etalon. At point <math>c</math> the amplitude will be :<math>TR\,e^{2\pi i + 3ikl/\cos\theta}</math> The total amplitude of both beams will be the sum of the amplitudes of the two beams measured along a line perpendicular to the direction of the beam. We therefore add the amplitude at point ''b'' to an amplitude <math>T_1</math> equal in magnitude to the amplitude at point ''c'', but which has been retarded in phase by an amount <math>k_0l_0</math> where <math>k_0=2\pi n_0/\lambda</math> is the wave number outside of the etalon. Thus: :<math>T_1=RT\,e^{2\pi i+3ikl/\cos\theta-ik_0l_0}</math> where <math>l_0</math> is seen to be: :<math>l_0=2l\tan(\theta)\sin(\theta_0)\,</math> Neglecting the <math>2\pi</math> phase change due to the two reflections, we have for the phase difference between the two beams :<math>\delta=2kl/\cos(\theta)-2k_0l_0\,</math> The relationship between <math>\theta</math> and <math>\theta_0</math> is given by [[Snell's law]]: :<math>n\sin(\theta)=n_0\sin(\theta_0)\,</math> So that the phase difference may be written :<math>\delta=2nkl\,\cos(\theta)\,</math> To within a constant multiplicative phase factor, the amplitude of the m-th transmitted beam can be written as :<math>T_m=TR^m e^{im\delta}\,</math> The total transmitted beam is the sum of all individual beams :<math>A_T=\sum_{m=0}^\infty T_m=T\sum_{m=0}^\infty R^m\,e^{im\delta}</math> The series is a [[geometric series]] whose sum can be expressed analytically. The amplitude can be rewritten as :<math>A_T=\frac{T}{1-Re^{i\delta}}</math> The intensity of the beam will be just <math>A_TA_T^*</math> and, since the incident beam was assumed to have an intensity of unity, this will also give the transmission function: :<math>T_e=A_TA_T^*=\frac{T^2}{1+R^2-2R\cos(\delta)}</math> ===Another expression for the transmission function === [[Image:LASCO C1a.png|thumb|200px|A picture of the solar corona taken with the LASCO C1 coronagraph which employed a tunable Fabry-Pérot interferometer to recover scans of the solar corona at a number of wavelengths near the FeXIV green line at 5308 Å. The picture is a color coded image of the doppler shift of the line, which may be associated with the coronal plasma velocity towards or away from the satellite camera.]] Another useful expression for the transmission function may be derived as follows: The sum representation of the amplitude <math>A_T</math>&nbsp; may be used directly to express the transmission function: :<math>T_e=T^2\sum_{m=0}^\infty \sum_{n=0}^\infty R^{m+n}\,e^{i(m-n)\delta}</math> Defining <math>l=m-n</math>, rearranging terms, and using the [[geometric series]] formula on ''R'' yields :<math>T_e=\frac{T^2}{1-R^2}\sum_{l=-\infty}^\infty R^{|l|}\,e^{il\delta}</math> The terms of the sum are seen to be the [[characteristic function]] of the [[Lorentz distribution]] which allows the sum to be written: :<math>T_e=\frac{T^2}{1-R^2}\sum_{l=-\infty}^\infty \int_{-\infty}^\infty L(\delta-\delta';\gamma)\,e^{il\delta'}\,d\delta' </math> where <math>L(x,\gamma)</math> is the Lorentz distribution: :<math>L(x;\gamma) \equiv \frac{\gamma}{\pi (x^2-\gamma^2)}</math> and <math>\gamma\equiv\ln(1/R)</math>. The order of integration and summation may be interchanged which yields a sum over the exponential term alone. This sum is seen to be a [[Dirac comb]] <math>D_T(x)</math> and so the transmission function is seen to be the [[convolution]] of a Lorentzian function and a Dirac comb: :<math>T_e=\frac{2\pi\,T^2}{1-R^2}\,\,L(\delta;\gamma)*D_{2\pi}(\delta)</math> ==References== *{{cite book | first = G. | last = Hernandez | year = 1986 | title = Fabry-Pérot Interferometers | publisher = Cambridge University Press | location = Cambridge | id = ISBN 0521322383 }} *[http://www.micronoptics.com/telecom_ffp.htm Micron Optics' optical fiber etalons] 4544c1f7d6183b2e8b0538adcad39310be38b68f 0 228 304 303 2013-05-12T02:51:48Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==Some Uses for Everyday Items in Holography== by John Pecora Here are some tips for saving money on ‘lab’ equipment. It is surprising how many everyday objects can be used to good effect in holography. These are just suggestions. Please remember that it is your responsibility to pay attention to safety, and use common sense. *Heating pads used with three or more settings can be used as adjustable heaters for processing trays. Simply put the heating pad under the tray and turn the pad on to the desired setting. *Black foam board can be used for blocking stray light. The type that is black throughout is best as the edges stay black even when they are cut. This material can also be used for making an iris. *A shutter can be made from most old 8mmmovie cameras. They have a low voltage electric shutter. Remove this unit and set up a circuit with the original voltage of the camera, and a switch. *A thick piece of glass, 1/4 inch or thicker, can be used as a beam splitter. Using the thick piece of glass allows a small piece of electric tape to be placed over the glass to block the secondary reflection off the back. *Sandwich boxes can be use as processing trays and also as storage for the chemistry without having to pour the liquids back into bottles after each session. They come in many sizes and shapes with airtight lids. Store sealed containers with chemicals in a dark, dry, cool place when not being used. *Rubber inner tubes can be used as the dampening mechanism between a holographic table and the support legs. *A slab of granite can be used as a holographic table. *Most old overhead projectors contain large front surface mirrors and large Fresnel lenses. They can be purchased at yard sales and flea markets for just a few dollars. *Most photocopiers and fax machines contain front surface mirrors. *New Jefferson Nickels have a weight of 5 grams and new Lincoln Pennies have a weight of 2.5 grams. Standard paper clips have a weight of 1 gram. To verify the weight of the paper clips put a nickel on one side of the balance and find 5 paper clips of the same size that equals the nickel. These can be used on a balance for measuring out chemicals. *A hair dryer can be used to dry a piece of holographic film or plate after processing. Drying intensity and heat is variable with very inexpensive dryers. *Polarizers can be found in polarizing sun glasses. These can be used to adjust the intensity of polarized laser light by inserting the polarizer in the beam path and rotating. They can also be used to check the polarization of light at different locations in an optical set-up. *Two pieces of window pane glass and binder clips can be used to sandwich a piece of holographic film. This will hold the film rigid and flat. *A microwave can be used to warm the deionized or distilled water needed for mixing up processing chemistry. But please be careful to keep chemical-contaminated containers separate and secure. One method is to heat the water in a clean container in the microwave and then pour it into the chemical container for mixing, always keeping the clean container free of any chemicals. *Two-part, fast-hardening epoxy is great for securing two pieces of metal without the need for drilling and tapping. This also allows easy disassembly with just a small sharp blow to one of the pieces. *A pinhole can be made by sandwiching 5 or 10 pieces of aluminum foil together and poking with a pin while the pile is on a hard piece of rubber. Each piece of foil will have a slightly different size of pinhole. *Automobile windshield wiper blades can be used as a squeegee. If you epoxy two blades to a pair of scissors then, when the scissors are closed 3/4 of the way, you can squeegee both sides of the film at the same time. For plates this is not necessary as you can do one side at a time with a single blade. *Clothes pegs on a line can be used to hang up films to dry. After clamping the film at two corners with the pegs, clamp two more at the bottom corners as weights to keep the film straight while drying. *Dishwasher drying agent can be in place of PhotofloTM in the final rinsing bath. Use an agent that does not have fragrance and, preferably, one that is clear. *Sodium carbonate can be purchased cheaply as a chemical for increasing the pH of swimming pools and spas. *Sodium bisulfate can be purchased cheaply as a chemical for decreasing the pH of swimming pools and spas. *Sulfuric acid can be purchased as car battery acid. Most formulas call for concentrations that are lower than that sold as auto battery acid. *Black Sanford Sharpie markers, which come in different sizes, are ideal for blackening optics, mounts and anything small you want to reduce reflections on. They are permanent markers that write on almost anything. *Paper MateTM liquid paper correction is great for painting objects for holography. It dries to a flat white and diffuses the light very well. *A disposable shower curtian works well as a dust protector for a collimation mirror. fe6b24a607672d1089e351c9f6889efc64c58fb7 0 229 306 305 2013-05-12T02:51:48Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki In order to find the optimum exposure and development times it is possible to make exposure tests. There are many variations on the method but Graham Saxby's method works well if you have your film lying flat in a single beam reflection setup. (Any other setup will only take a slight variation using a moving slit or tape.) Calculate your best estimate at the proper exposure time. Place 4 coins on the film. Remove one coin after 1/4 of you estimate, remove one more coin after 1/2 of your estimate, remove one more coin at your estimate, remove the last coin at double your estimate and then shut off the exposure at 4 times your estimate. If you use tape, you can remove tape at the proper times. This makes strips of differing exposure, if you cut the plate across the strips and develop each piece for a different time you can see the effects of exposure and developing times. ==Some tips from ErichRose== After screwing around with one inch vertical strips I came up with my own little system: I was shooting 4x5s so I made a black cardboard mask that had one quadrant missing (~2x2.5). It was cut just a bit smaller than the plate so it would nestle in front of the plate between the edges of the plate holder, then it was tacked in place with hot glue. I started with the upper left corner, then upper right, lower right & bottom left. In other words clockwise* around the plate. I usually did 1/2 the calculated exposure, 1x, 1.5x and 2x for the first test. The beauty of the quadrants was the ease of lining up the card. I just flipped it around or rotated it. I had minimal overlap on the exposures. It also gave me a better field of view for assessing the exposure. The "one inch" strips often ended up being 3/4, 1-1/4, overlapped, a thin strip unexposed, etc. I could easily live without the fifth exposure. After a while you get a feel for how much the exposure will need to be even if one of the four isn't quite right. I also made good use of that fine point Sharpie marker and labeled all test plates immediately. And I kept good notes. Which I am re-reading twenty years later. Just wish I was going to be working again with 8E75 so I wouldn't have to do so much over agian. * It's a good habit to make a habit of always doing things in the same order: clockwise, left to right, top to bottom, etc. When working in the dim safe light this will make it easier to keep everything straight. ==Notes from Ed Wesly== *ErichRose is on the right track, by using a quadrant system. This takes into account the natural Gaussian fall-off of the spread laser beam, unlike the strip methods where the peripheries are seeing different flux energies at the edges compared to the centers. The quadrant captures the radially diminishing exposures, so that there is a realistic comparison of same intensities in the center of the plate but with different exposure times. *Another point to make is that the exposure times should be logarithmic, like the response of the eye. In other words, a series like 1", 2", 4", 8", 16" ... as appropriate would be good, or for finer tweaking, 1", 1.4", 2", 2.8", 4", 5.6", 8", 11", 16" ... d9d582474e84ba91e09b43ac97ea99ca6b50d68f 0 230 308 307 2013-05-12T02:51:48Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Factor''' - number that tells how many times exposure must be increased in order to compensate from loss of light. *'''Fahrenheit scale''' - scale of temperature named after its German originator, G. D. Fahrenheit. On this scale, the freezing point of water is 32° F, and the boiling point of water is 212° F. F=(C*(9/5))+32 *'''False attachment''' - part of one object seen behind another so that lines, shapes or tones seem to join up. A composition device used in various ways to produce images in which foreground and background objects appear to occupy the same plane. *'''Farraday shutter''' - high-speed shutter using a pair of crossed polarizers, between which is a glass block within a coil. When a voltage passes through the coil, the plane of polarization changes, allowing light to pass through the second polarizer. *'''Ferric chloride''' - bleaching solution used on negative materials. *'''Ferrotype process''' - method of creating direct positive images with dark enameled metal plates as a base. Also known as the tin-type process. *'''Film characteristic curve''' - describes a graphical relationship between the logarithm of the exposure value (horizontal axis) and density (vertical axis) of film. Each brand of film exhibits a different characteristic curve. *'''Finality development''' - prolonged development, reducing silver halides affected by light to silver until no further image density improvement occurs. *'''Flashing''' - briefly and evenly exposing photographic materials to white light.Often used to lower contrast of printing paper, when the flashing exposure is made in addition to the regular exposure. *'''Fluorescent whites''' - brilliant highlights produced by applying a fluorescent agent to a printing paper base. The print can also be treated after washing with a fluorescent whitener or dye solution. *'''f numbers''' -e numbers on the lens barrel indicating the size of the aperture relative to the focal length of the lens. f numbers are calculated by dividing the focal length of the lens by the effective diameter of the aperture. *'''Fogging''' (Fog) - produces an overall veil of density on a negative or print, which does not form part of the image. It can be achieved by chemicals or exposing the sensitive material to light. *'''Frilling''' - wrinkling and separation of the emulsion along the edges of its support material. *'''Futurism''' - art movement started in Italy c. 1910, characterized by an aggressive rejection of tradition, and the representation of the dynamic movement of machinery. 675feb945f4e4838bfbcf024b58f52d88dc8e935 0 231 310 309 2013-05-12T02:51:48Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki FACETS OF LIGHT Colors, Images, and Things That Glow in the Dark, K. C. Cole, Exploratorium San Francisco, CA, 1980. 107 pp. This is not an easy book to find, but it is worth the effort in tracking it down. Part of the problem is that the Exploratorium, founded by Robert Oppenheimer, has some problems with the US Government, and doesn’t believe in ISBN numbers. The book is basically a catalog of the optical exhibits at the Exploratorium, so it doesn’t read like a normal textbook. It’s hard to know 25+ years later if any or most of these exhibits still exist, but having some familiarity with optics will help flesh them out in the mind’s eye. As an added bonus there was a packet of materials glued in the back cover. A diffraction grating, 4 colors of gels, and a couple of pieces of Polaroid enabled the reader to explore in their own pad the facets of light. K. C. has written a number of other science books, also worth reading. A companion to this volume is Vision: In the Eye of the Beholder, also an Exploratorium Publication. I couldn’t find the list price of the book, but I believe it was under $10 when new. Use this a guideline when looking for copies on-line, because I have seen it at extortionate prices. -Ed Wesly bca16af3156fe87d1e3cddb497e457b37774e61f 0 232 312 311 2013-05-12T02:51:49Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki This page is under construction! > I do have > one question, I was under the impression that the only way I could make an > isolator is with a Faraday Rotator and a polarizer. This is well out of my > budget. It is the only true isolator I know of. > However a 1/4 wave plate and a polarizer sounds easy. I just purchase 4 1/4 > wave plates from e-bay for cheap and if I can use one of them it would be > simple. > > How does a 1/4 waveplate and a polarizer function as an isolator? This is not a true isolator. It only works to block back-reflections from a mirror (or other reflective surfaces, as long as they maintain the polarization). It is simple, but not so simple to understand. When I first came across it, it took me some time, and I was standing in front of the set-up. The setup: The light goes through a polarizer, a 1/4-wave plate (oriented at 45 degrees to the polarization) and hits a mirror. There are two ways to look at it: 1. The light goes through the 1/4 plate twice (forwards and backwards), making it effectively a 1/2 plate ==> the polarization is turned by 90 degrees and cannot pass the polarizer on its way back. 2. The light goes through the polarizer and then through the 1/4 plate. The result is circular polarization. At the mirror, the light is reflected back, still in circular polarization. At the 1/4, it is converted back to linear, but at 90 degrees to its original orientation. If the reflection depolarizes the light (e.g. on a diffuse surface), it doesn't work any more. That's why it is not a true isolator, since it doesn't block arbitrary light in the reverse direction. If the reflection de-polarizes only to a certain degree (like atmospheric back-scattering, which generally de-polarizes only a little bit), then it reduces the amount getting back significantly, but doesn't block it 100%. > Holographers have a big problem with the back reflection changing when the > shutter opens. Any level of isolation would be extremely helpful. Especially > with diode lasers. So you have to look at the nature of your back-reflection. Either use one polarizer and insert and rotate the 1/4 plate to see whether it helps at all, or look through a polarizer at the back-reflected light and see whether turning it will have any effect (assuming that your laser light is polarized). If yes, the 1/4 plate will help to the same degree. However, be sure that the 1/4 plates you have are really for 635nm. Some of them are only narrow bandwidth. Anyway, maybe it is even best to play around first: use a plain mirror to reflect your laser almost back into itself (let it hit a screen next to the laser aperture just a few mm besides the aperture). Then insert the polarizer, so that the forward and reverse beams go through it. If the laser is polarized, you should see not much of an effect, if the polarizer is oriented properly. Then insert the 1/4 plate between the polarizer and the mirror and rotate it. The reflected spot should change from full power to almost non-visible within 45 degree rotation. If the polarizer is a polarizing beam splitter (like a cube), then you should see the reflected beam coming out of the side of the polarizer when it is minimum at the straight reflection. It is quite impressive, when you see it the first time. 39e3a56a4bab60b183b61ffddce88e5f445bd2b0 0 233 314 313 2013-05-12T02:51:49Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki A Farady rotator is made from a non-linear material with an electric current passing either across the light path or along the light path in the crystal. They are used in [[Ring Laser|Ring Lasers]] and in [[Faraday Isolator|Faraday Isolators]]. A Faraday Rotator rotates light using the Faraday Effect. The degree of rotation is controled by an induced magnetic field. The two main uses for a Faraday Rotator are putting a polarizer in front so that back scatter is rotated and blocked by the polarizer and using them with wave plates to make a ring laser. [[Image:FaradayRotator.png]] The plane of linearly polarized light is rotated when a magnetic field is applied parallel to the propagation direction. The empirical angle of rotation is given by: [[Image:FaradayEQ.png]] *Where β is the angle of rotation (in radians). *B is the magnetic flux density in the direction of propagation (in teslas). *d is the length of the path (in metres) where the light and magnetic field interact. *Then V is the Verdet constant for the material. This empirical proportionality constant (in units of radians per tesla per metre, rad/(T·m)) varies with wavelength and temperature and is tabulated for various materials. 1d54e7ccb6e0a3d9444b94da4fbb3fe714bef7ce 0 234 316 315 2013-05-12T02:51:49Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Files either cut by being abrasive or by being sharp. Abrasive files work like sand paper. Diamond is the most common abrasive file. (Another realated tool is the [[Rasp]]. Cutting files come in different shapes: *Mill *Round *Half-Round *Machinists' Flat *Three-Square *Square *Flat *Taper *Knife *Warding And in different tooth patterns (Listed from Coarse to Fine): *Coarse double-cut *Coarse *Bastard double-cut *Bastard *Smooth *Dead Smooth *Fine Files can be sharpend a few times by being placed in an acid bath. If you use lots of files it is worth the cost if you only need to replace a couple of files each year don't bother sharpening. After the teeth are cut on a file the file is hardned. This makes them easy to break. That can be used to yor advantage if you need to shorten a file. After shortening, grind the end making sure not to heat the file. (Use a bucket of water to cool the file after every few seconds of grinding. Choose course files for softer materials and for leaving rougher surfaces with quicker stock removal. Choose finer files for harder materials and finer finishes with slower stock removal. f6cb1350e1d5f3adda571a68477f5b5fe3e46240 0 235 318 317 2013-05-12T02:51:49Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Holding the film stable is a prime requirement for making a hologram. Film holders can be as simple as holding up a glass plate with a couple of magnets. But, it must not be forgotten that the film must be held absolutely stable. Film holder Plans: #[[Machined Film holder]] #[[Angle Iron Film Holder]] 15c26b01f46104830824ad3d0eb9f718f034bcec 0 236 320 319 2013-05-12T02:51:50Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Fixer removes the unexposed silver halide remaining on a hologram leaving behind the reduced metallic silver that forms the image. By removing the unexposed silver halide, the fixer prevents any further reaction of the silver salts and ensures a permanent image. Most fixers are based on the thiosulfate ion, especially ammonium thiosulfate. Sodium thiosulfate or 'hypo' was the commonly used fixer. Both fixers work best in acid conditions and this is usually created using small quantities of acetic acid. e1f95c7b90e22a98713bad2503d39cafa1b89d63 0 237 322 321 2013-05-12T02:51:50Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:FDeFreitas.jpg]] [http://www.holoworld.com HoloWorld] Frank started holography in 1983. While having no formal training in science, he has made a career in science and technology. He runs [http://www.holoworld.com HoloWorld], perhaps the most popular web site for holography. He is one of the pioneers of using laser pointers to make holograms. He is the author of "Shoebox Holography" and runs an internet radio program, [http://www.holoworld.com/holotalk/index.html HoloTalk]. He also teaches holography to childeren in workshops. cdaeaf38969ea9ea2ae896c104066cec2660ad32 0 238 324 323 2013-05-12T02:51:50Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:FresnelRomb.jpg]] From: [http://www.klccgo.com/fresnelrhomb.htm Karl Lambrecht Corporation] Used to rotate the polarization. The advantage as compared to [[Holography_Technology#Wave)Plates|Wave Plates]] is their broadband nature, as they are typically useful throughout the whole visible spectrum. 5729860a69a81d4b3698f3456d3328ae927ac3f3 0 240 328 327 2013-05-12T02:51:51Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Fringe lockers can be used to diagnose problems with a set up. The output is sent to a scope to find out the frequency of the problem. They can also be used to correct very small instabilities with set ups. Depending on the movement capacity of the piezo element or piezo element stack, the fringe locker can compensate for movements from a few fringes up to 10's of fringes. The fringe locker used for corrections is most widely used for long exposures. The types of movement they can compensate for depends on the frequency response. They work on the principal that a fringe from the setup is expanded with a lens so that one fringe is in between two photodetectors. If the fringe starts to move a difference in voltage between the two photodetectors is noticed. This signal is sent to a piezo element under a mirror in one of the beam paths in order to change it's length and hold the fringe still. A commercial example is the [http://www.stabilock.com/ Stabilock]. A home made circuit from Joe looks like this: [[Image:Fringelock.gif]] b61529fe5a227226bf270b7308c46f650fb14b98 0 241 330 329 2013-05-12T02:51:51Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki From "Electron Micrographs of Hologram Cross-sections" Motoo Akagi, Tadao Kaneko, Tsutomu Ishiba. Applied Physics Letters, Vol 21, No. 3, 1 August 1972. The photos below were made with [http://en.wikipedia.org/wiki/Transmission_electron_microscope| Transmission Electron Microscopy]. [[Image:Fringes1.jpg]] 20u wide photo of an amplitude hologram in Kodak 649F Film. [[Image:Fringes4.jpg]] Same sample zoomed into 5u wide. [[Image:Fringes2.jpg]] Phase hologram in Kodak 649F about 25u wide. [[Image:Fringes3.jpg]] Phase Hologram in Scientia 14C75 film about 25u wide. [[Image:Fringes5.jpg]] Same sample zoomed in to 5u wide. [[Image:Fringes6.jpg]] Cross section of an amplitude hologram on Kodak 649F about 30u wide. fa0e58a62971eae89244587eae579fccc7fecfb2 0 242 332 331 2013-05-12T02:51:51Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Galvanography''' - technique of electroplating a gelatin relief image created photographically to produce a photomechanical printing plate. *'''Gamma''' - measurement used in sensitometry to describe the angle made between the straight line portion of the characteristic curve of the photograph emulsion and the base of the graph. The gamma is the tangent of the angle so formed. *'''Gelatin filters (gells) - filters cut from dyed gelatin sheets and held in front of the lens or studio light.''' *'''Gelatin sugar process''' - daylight printing process using paper with a sugar and dichromate coating, which hardens on exposure to light. *'''Ghost images''' - bright spots of light, often taking the shape of the aperture, which appear in the camera viewfinder or in the final photograph when a lens is pointed at a bright light like the sun. Ghost images have been almost eliminated through the use of multi layer coatings of the lens elements. *'''Glaze''' - glossy surface produced on some (non resin coated) printing papers. It is achieved by placing a wet print to to a heated drum or clean polished surface. Glazed print produce denser medium blacks than their matte counterparts. *'''Gold chloride''' - soluble chemical used in gold toners. *'''Gold mean''' - compositional technique used to determine the "ideal" position of the main subject in the frame. It is based on creating a rectangle from a square. A line drawn from the center of one side of the square to the opposite corner becomes the radius of an arc. The side of the square is then protracted until it meets the arc, and from this point a rectangle is constructed. The side of the square which remains in the rectangle indicates the point at which the subject should be placed. *'''Gray card''' - card with an 18 percent gray tint (reflectance) used to determine exposure by taking a meter reading from subject light reflected by the card. *'''Greenies''' - Slang, These are often found in DCG processing and appear as a green blob in the image. *'''Gum arabic''' - water soluble gum obtained from the Acacia tree and used in coatings of a number of photographic processes. *'''Gum bichromate''' - contact printing process once very popular for the manipulative, impressionistic effects it makes possible. Drawing paper is coated with a mixture of gum, potassium bichromate and a pigment of any chosen color. This is then exposed to light behind a negative. Also known as the photo aquatint process. Gum platinum process - combination of gum and platinum printing. a1b7c86b4aaef37ebfbfcb3ab30fd5a0a3d1b33d 0 243 334 333 2013-05-12T02:51:52Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==G307== (initial entry by John Pecora) This is Jeff Blyth’s formula for plates that exhibit an increased sensitivity to the green wavelengths 514 and 532. I have been exposing between 5 to 20mJ/cm^2 with very bright results. First it is necessary to coat plates with an emulsion of just gelatin and water using your preferred method (veil, bar, spin etc.) followed by curing of at least 12 hours. After curing the plates can be stored indefinitely, preferably in the refrigerator and just a few can be sensitized only when needed. ==Pre-exposure== To sensitize the plates, make up a solution as follows; Weigh out in order:- *0.5g glycerine *0.3g Aluminum Sulfate or Alum *100 ml distilled or de-ionized water *dissolve everything up then add: *5g potassium dichromate. Chill the solution to 5 degree C and then pour the solution into a container just larger then your glass plate. At this point a red safelight needs to be used and the standard yellow bug light for DCG will not work. Tilt the container to the side slightly, now take the glass and place it in the container, putting the edge in the deeper end of the liquid first and laying it down all in one motion while leveling the container. You will see the liquid slide across the top of the plate evenly. Only leave your plate in the solution for about half a minute then shake the plate free of droplets and wipe over the glass back with a paper towel. Stand the plates up against a wall at an angle and gently blow with a small desk fan or a hair dryer that has a cool setting until they are touch dry. At this point the alum in the formulation starts doing its job and is hardening up the coating a bit but it is only a gradual step and it is not instant. Now your plates should be used as you normally use them, needing to be shot at once or refrigerated for later use. AMENDMENT: '''Storage note about this solution''' If possible always try to use freshly made solution. However it can be stored in the dark in a fridge for a few days. The glycerine content will degrade rapidly if left in a bright light and slowly degrade in a dark reaction in the fridge. It may be possible to rejuvenate it with more glycerine but it is unlikely to be as good as the fresh stuff. ==Post exposure treatment== You need to have your oven at 100C (212F) and have a flat clean metal plate in it so that the metal instantly and evenly heats up your dry exposed plate. I have found that for a 4x5 plate 2 minutes is a good starting point. Depending on hardness of gelatin and exposure energy you may need to adjust this time. If the plates come out milky, increase the time. For the brightest hologram keep the baking time as low as possible without the plate coming out milky. After baking at 100C take the plate out and put it immediately onto a cold metal surface to rapidly and evenly cool the plate. Once the plate has cooled to room temperature, process with water and alcohol just as the standard DCG would be processed but use DI water in a container as the KDi will be lost into this water. When you are finished Sodium Metabisulfite can be added to change the CrVI to CrIII which is more environmentally friendly. You may need to leave the plate in the water rinse a bit longer to get all of the potassium dichromate out depending on the thickness of your emulsion. I use two baths, one for the majority of soaking to get most of the KDi out and the second as a quick final rinse. Once you have CrIII it will then be able to be precipitated out in a saturated solution of your sodium carbonate. An alternate drying method would be to just hit the plate with the hair dryer or other blower for just a few seconds to get the majority of alcohol off but then put the plate back into the oven at 100C until completely dry. ==Questions and Answers== ''' Q. What qualifies as "curing" for newly coated plates? 12 hours at any particular temp or humidity ? Well, the key is to have the gelatin cured enough to remain on the plate and not dissolve in the sensitizing bath. I would coat and leave in positive flow bench for 4 - 8 hours. At this point I would put the plain gelatin the fridge for later sensitizing and use. 12 hours is the minimum and as it is plain gelatin, storing for days or weeks is no problem. I believe 12 hours would be adequate for most environmental conditions. ''' Q. At what point does the sensitizer become light sensitive? Should the mixing be carried out under a safelight? Yes. Anytime you add KDi or AmDi to glycerine or gelatin you should use a safelight. ''' Q. What happens if one leaves the plate in solution more than 30 seconds? The only negative I can see is the gelatin will start to dissolve. ''' Q. Any chemists out there have any suggestions for a "preservative" to limit the glycerin dark reaction? Why do we want to limit it? It is the dark reaction additive that gives the G307 its increased sensitivity. ''' Q. Why is a cold plate used after post-exposure baking? This is used for larger (4x5" and up) plates so that the emulsion cools uniformly. Without this you may find that the brightness varies from the center to the outer edge of the plate due to differential cooling. Also, to cool the plate immediately such that the baking time can be more precisely controlled. The post baking is the additional hardening. If the plate was allowed to cool to room temp without a cold plate, obviously the hardening from the baking would be extended. Vary the room temperature and the control time is lost. ''' Q. What does this mean? "Once the plate has cooled to room temperature, process with water and alcohol just as the standard DCG would be processed but use DI water in a container as the KDi will be lost into this water." Soak the plate first to dissolve out the KDi? Yes, after the baking hardening there is still some unused KDi that will dissolve out. It is best to dissolve this out in a container such that it can be neutralized before disposing. ''' Q. "An alternate drying method. . ." Alternate to what? Alternate to the standard DCG method of drying which is with forced hot air after the last alcohol bath. ''' Q. What processing regime have people had good success with? Combinations of alcohol %, fixer, etc. DCG processing can be on [[A Beginners Approach to DCG]], [[MBDCG]] and [[The Mechanics of Gelatin and the DCG Process]]. It's unclear if or how the process might be changed for for G307. There is no fixer used in the G307. The G307 is different only up to the water rinse bath just prior to the alcohol dryings. All papers and techniques to change bandwidth or color from the water bath on, for standard processing, should apply. ''' Q. When using Sodium Metabisulfite to make the CrVI more environmentally friendly, how much should be used? How can one tell when one has added enough to change the CrVI to CrIII? CrVI is orangish in color. CRIII is bluish. When the solution has turned blue, that should be enough. A little more is better then not enough. I always add till blue and then some extra. Sodium Metabisilite is inexpensive. Unless you know exactly how much KDi is in the solution, I am not sure an exact measurement of Sodium Metabisulfite can be found. I wonder if there is a test to check if there is any CrVI left in the solution...??? ff7d3571d6e62bf34fd3101cac17178ee943aeb0 0 244 336 335 2013-05-12T02:51:52Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:GLippmann.jpg]] French physicist who received the Nobel Prize for Physics in 1908 for producing the first colour photographic plate . He was known for the innovations that resulted from his search for a direct colour-sensitive medium in photography. Though born of French parents in Luxembourg, Lippmann grew up in Paris and was a bright but unruly student. Despite the fact that he never received his teacher's certificate, he was appointed professor of mathematical physics at the Sorbonne in 1883. He later was appointed head of the Sorbonne's Laboratories of Physical Research (1886). Lippman's scientific talents were varied, but he was best known for his contributions in the fields of optics and electricity. He did early, important studies of piezoelectricity (precursors of Pierre Curie's work) and of induction in resistanceless, or superconductive, circuits (precursors of Heike Kammerlingh-Onnes' validations). He also invented the coleostat, an instrument that allowed for long-exposure photographs of the sky by compensating for the Earth's motion during the exposure. In 1891 Lippmann revealed a revolutionary colour-photography process, later called the Lippmann process, that utilized the natural colours of light wavelengths instead of using dyes and pigments. He placed a reflecting coat of mercury behind the emulsion of a panchromatic plate. The mercury reflected light rays back through the emulsion to interfere with the incident rays, forming a latent image that varied in depth according to each ray's colour. The development process then reproduced this image, and the result, when viewed, was brilliantly accurate. This direct method of colour photography was slow and tedious because of necessarily long exposure times, and no copies of the original could be made. It never achieved popularity, therefore, but it was an important step in the development of colour photography. [http://nobelprize.org/physics/laureates/1908/lippmann-bio.html Nobel Prize's Biography of Gabriel Lippmann] b263f6cbbc8d8b6541b90b344f273c27ea052fc8 0 245 338 337 2013-05-12T02:51:53Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Gelatin Type A - Acid process used in production of product. Primarily pork skins. Type B - Alkaline process used in production of product. Primarily cattle hides. Type B (bovine) - Alkaline process used in production of product. Specifically cattle bone. According to one supplier, this type may contain small amounts of silver salts which could increase speed of Silver Halide films although it was unknown how much (if any) effect this might have. Bloom Stength - This is a standard measurement that determines hardness of gelatin after a specific period of time. The higher the Bloom number the harder the gelatin. For Dichromated Gelatin emulsions, High bloom and type B is best. Notes: *It is best to gradually add the gelatin to room temperature water, let it swell up, then heat the swelled mixture while stirring to dissolve. *Cooking with too high a temperature destroys the gelatin - use a double boiler and thermometer or similar arrangemnet. *Knox Unflavored Gelatin has been shown to work well for DCG Holography. *Gelatin solution can be stored in a refrigerator and repeatedly reheated and reused for a while, but eventually goes bad due to mold etc. *Increase concentration of gelatin in water for thicker emulsion. *Heat glass to be coated for thinner emulsion. *Lower temperature of emulsion during coating for thicker emulsion. ==Measuring the Hardness of Gelatin== It is possible to measure the hardness of gelatin according to an article by Oliva, Boj and Pardo (1983) # Weigh gelatin. # Soak the gelatin in distilled water at 18C of 15 minutes. # Weigh gelatin again. # The swelling factor is S=(W-W0)/W0%. Higher values of S denote softer gelatin. For reference use: * AGFA 8E75HD plates had a swelling factor of 25. (Very hard) * Kodak 649F plates had a swelling factor of 200. According to the authors of the article, this was why the Kodak plates were so much better for adaptation to DCG. *[[Properties of Gelatin]] by Bernard Cole - mirrored with permission 53add30423321eed32de5938b83d2a15e7236898 0 246 340 339 2013-05-12T02:51:53Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:GlassCutter.jpg]] Glass cutters work by damaging the glass along a specific line. For a straight cut place a straight edge along the work and score the glass with the wheel. After scoring, the glass is placed with one end of the underside of the score (score still on top) on top of and centered over the ball. Then an even pressure is applied to both sides of the glass. If the glass is large (a long score), a second ball should be used, one under each underside of both scored ends or a straight edge place at the underside just at the score. Since glass will tend to break where it has been damaged it will break along the line. Tips *Using a steel or aluminum square for cutting glass Holo-Plates insures the glass is square. *Make sure the glass cutter is sharp (not worn out). *Make sure the cutter wheel spins freely. *Don't use excessive pressure. *For straight lines use a steel rule or similar. *Make sure to start at the edge of the glass. *Keep even pressure along the entire score. *Keep a smooth continuous motion until done, do not stop and restart. *Only make one score - If the cutter skips only go over the unscored part but try to avoid this. *Pay special attention to the end of the cut. *Some people find the ball at the handle end useful to tap the score line for thick glass. *Keep the score on top and break the glass down. *After the break, the noches on the cutter can be used to break off parts that did not break at the score but they will alway be rough and sharp. Safety: *Wear eye protection. *Handle large sheets with your finger tips and never your palms. a79d5bac40f8cd11af74185077ecb592d3ea1b7b 0 247 342 341 2013-05-12T02:51:53Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki *[http://google.com/groups?q=$1 '''Google''' "$1"] *[http://groups.google.de/groups?q=$1&hl=de alle '''Google Newsgroups''' nach "$1" durchsuchen] dcabf0ea1afac7b5c91b524c3e25012a09d0e6cd 0 248 344 343 2013-05-12T02:51:53Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [http://www.hmt.com/holography/cherry/cherry.html Web Site] 7c5e221c386a92d9cfa6c7f0ab4dd7f17afe3556 0 249 346 345 2013-05-12T02:51:53Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Greg Quinn worked at the National Physical Laboratory between January 21st 1974 and September 15th 1985 in the holographic interferometry group (at that time, part of the Department of Mechanical and Optical Metrology). Working under Tony Ennos, Eddie Archbold and finally Dave Williams, he created many display holograms that have been presented both internally and at national meetings since then. Following his time at NPL, he studied biochemistry at Leeds, and gained his Ph.D. in molecular biology at Southampton University. Greg is currently principal investigator of the Mobile Data Visualization Lab at the San Diego Supercomputer Center, at the University of California San Diego. He's married with one son. f5d97ab7d33526c080a4581898ad13cf2f92a773 0 250 348 347 2013-05-12T02:51:54Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:GFavalora.jpg]] Gregg E. Favalora (Arlington, Mass., USA) *B.S., Yale Univ. (1996) *S.M., Harvard Univ. (1998) *Founder and CTO, Actuality Systems (1997-present) *[http://www.actuality-systems.com Actuality Systems, Inc.] *[http://www.greggandjenny.com/gregg Personal homepage] Gregg Favalora is not a holographer in the traditional sense. Rather, he has focused on the design and development of many three-dimensional display architectures since being bitten by the "3-D bug" in 1988. He holds a BSEE from Yale and a Masters' in Engineering Sciences from Harvard, which he left in 1997 to found Actuality Systems, a firm specializing in 3-D visualization for medical imaging, oil & gas, and entertainment. His research interests include optics, 3-D displays and electro-holography, biologically-inspired electronic systems design and "neuromorphic engineering", and industrial design. In his spare time he wishes he were better at playing the drums and the ancient strategy game of go. In 1996, while a student at Yale, Gregg developed the first parallel raster-scanned 3-D display under the guidance of Prof. Peter Kindlmann. It used 32 laser diodes in conjunction with a polygonal mirror scanner to illuminate a rotating diffuse screen with 32,768 voxels. The autostereoscopic, full-parallax volumetric image occupied roughly egg-sized volume. It is described in U.S. Pat. 5,936,767 and has been in operation - through at least 2006 - in Becton Center at Yale University since 1996. In 1997, Gregg founded Actuality Systems to develop software and opto-electronic systems for true 3-D visualization. In 2001, Actuality's engineers developed the world's highest-resolution volumetric 3-D display. Now marketed under the name Perspecta(r), it generates 10"-diameter 3-D imagery by projecting patterned light at 6,000 frame/s onto a swiftly rotating diffuse screen. The imagery created by Perspecta is composed of approximately 100 million voxels. Through 2006, Actuality's innovations include: "Spatial Visualization Environment," the world's first software platform that interprets graphical data from standard applications and processes them for displays of a wide variety of underlying physics, such as multiplanar displays, holographic displays, and highly-multiview displays. With a team including Oliver S. Cossairt, Rick K. Dorval, and Sam Hill, showed that it is possible to create a volumetric display with voxels having viewer-position-dependent effects, such as variable opacity. Developed several quasi-holographic "aerial" display systems that project free-floating imagery measuring 1" x 1" x 1" to 6" x 6" x 3". Working with leading hospitals to use volumetric 3-D displays for the review of cancer therapy plans using radiation oncology. Gregg is an inventor or co-inventor on: *U.S. Pat. 5,936,767, "Multiplanar autostereoscopic imaging system" *U.S. Pat. 6,183,088, "Three-dimensional display system" *U.S. Pat. 6,487,020, "Volumetric three-dimensional display architecture" *U.S. Pat. 6,512,498, "Volumetric stroboscopic display" *U.S. Pat. 6,570,681, "System and method for dynamic optical switching" *U.S. Pat. 6,940,653, "Radiation conditioning system" Gregg is a winner of the 1996 National Inventors' Hall of Fame / BFGoodrich Collegiate Inventors Award, is a member of the MIT Technology Review "TR-100" young innovators, and is a frequent speaker on the topic of entrepreneurship. Due in large part to the efforts of Actuality's engineers, his work has appeared in the Wall Street Journal, Wired, CNN Headline News, and a variety of major technology and medical publications around the world. 3c0bf31a507e99d41d9ea79633321e538a3af96e 0 251 350 349 2013-05-12T02:51:54Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Halation''' - diffused ring of light typically formed around small brilliant highlight areas in the subject. It is caused by light passing straight through the emulsion and being reflected back by the film base on the light sensitive layer. This records slightly out of register with the original image. *Halide *'''Hand coloring''' - process of applying color tints, in the form of paint, to a photographic image to create or enhance the color effect. *'''Hard gradation''' - term denoting the quality of harsh contrast in a photograph. *'''Hide''' - camouflaged barrier used by natural history and wildlife photographers. *'''High art photography''' - general term for an early form of artistic photography (1851-1870), in which photographers set out to match the style and subject matter of paintings of the period. *'''High key''' - photograph which contains large areas of light tones, with few middle tomes or shadows. *'''Highlights''' - the brightest ares of the subject, represented on a negative by dense deposits of black metallic silver, but reproducing as bright areas on the positive print. *'''Hill cloud lens''' - lens with a 180° angle of view, used for photographing cloud formations and other meteorological work. *'''Holding back''' - 1. Shortening the development time given to film to help reduce image contrast. 2. Method of decreasing exposure given to selective areas of the print. Also referred to as dodging. *'''Horizon''' - line at which earth and sky appear to meet. Its position, which can be altered by titling the camera or by cropping the image determines whether the sky or the landscape concentrates interest in the picture. A low horizon (tilting the camera up) concentrates interest in the sky while a high horizon (tilting the camera down) concentrates interest in the landscape. *'''Hydrobromic acid''' - acid liberated during the developing process by the reduction of bromide. *'''Hydrochloric acid''' - chemical used in some bleaching solutions. *'''Hydrogen peroxide''' - chemical used in hypo clearing agents. *'''Hydroquinone''' - reducing agent. It is used in developers to provide high contrast results in the presence of a strong alkali. *'''Hypo eliminator''' - chemical bath which removes traces of fixing agent from an emulsion. 7d136106547d30686a019bfbe5ac4a2565ed759f 0 252 352 351 2013-05-12T02:51:54Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Hack saws are hand saws that are used to cut metal. First, as with any material removal in metal, keep the blade and material well lubricated with cutting oil. This can be elliminated and is not as important with soft metals but is needed and will save your hacksaw blade with harder materials. They usually have finer teeth then wood hand saws and the blade should be put in such that the teeth point toward the user handle, not away from the user handle as in a wood saw. As the teeth are pointing toward the user, the cut into the metal is done on the pull stroke and not the push stroke. This allows a finer and more straight cut as the blade pressure during the cutting stroke is from the solid handle and not the tensioned far end. Finer teeth are used for harder metals and courser teeth used for softer metals like aluminum but both should still be metal cutting blades. Fine teeth can be used for hard and soft metals but course teeth should only be used for soft metals. Only apply slight pressure on the pull (cutting) stroke and no perssure at all on the push stroke. Do not force or excesssively bear down on the saw. Most of the time after the piece is cut there will be a burr on the end of the material. This can be filed or sanded away. 1ab56d044f06d5387e253916de943057fe64cce9 0 253 354 353 2013-05-12T02:51:55Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki A hand die is used to put bold thread on a piece of rod stock. A hand die looks like a hexigontal disk with a center hole shaped like a four leaf cloverthat has threads on it. The outside hexigontal fits into a handle to ease the turning of the die when cutting the thread on a rod stock. The threads are tapered thus a smaller diameter on one end and a larger diameter on the other end. There are diffferent die sizes for different stock rod sizes. If the rod is soft material the counterclockwise cut off steps, as described below, may be elliminated. First oil both the die and the rod stock and keep it well lubricated. More and often is better then not enough. Then find the larger diameter threaded side of the die. This will be marked on some dies. This larger diamter is the side the fits over the rod stock first. Start to turn the die clockwise (for standard bolt threads) until it starts to bite into the rod stock while keeping the die perpendicular to the rod stock. Once the die has started to bite into the rod stock, turn the die another 1/4 turn clockwise. Then turn the die 1/4 turn counterclockwise. This cuts away the material from the die and you can feel pressure give to ease of turning. Continue to turn the die 1/2 turn clockwise then 1/4 turn counter clockwise until the length of threading needed is complete. Once complete, unthread the die (counterclockwise) off the threaded rod stock. eb5850c671df1db90d3745b8d5c81bf70d8c2378 0 254 356 355 2013-05-12T02:51:55Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki A hand tap is used to make threads in a drilled hole, usually but not exclusively in metal. The tap looks like a bolt as it has threads but the thread are tapered from narrow at the point to the standard bolt thread size as you go up and the tap is usually made from a very hardened steel. Which means they are very hard but can snap or break easily. So do not use excessive force. It is better to take smaller cutting turns then described below then to force and break the tap off in the hole. As the tap is hardened it is almost impossible to drill out or remove one is has been forced and broken off in a hole. The tap usually has a cross bar at the top to allow ease of turning the tap. There are tap charts to look up the drill bit size to use for drilling the hole for final tap size. There are many size taps depending on bolt size. There is also a regular through tap and a bottom tap. When using a bottom tap is it recommended to use a through tap first to get the threads started, then use the bottom tap to finish the job. A bottom tap is used to tap a hole that does not go all the way through the material (thus past the taper on a through tap) but the threads should reach as close to the bottom of the hole as possible. For steel the most important thing is to keep the tap and hole well lubricated with oil. More and often is better then not enough. A good cutting oil is recommended. Once the hole is drilled insert the tap into the hole and rotate it clockwise (for standard bolts) gently until you feel it bite trying to keep it as perpendicular to the work as possible. Then rotate it clockwise another 1/4 turn. Turn it counterclockwise 1/4 turn. This breaks away the cut metal from the cutting threads. Again rotate it clockwise for 1/2 a turn and then counterclockwise 1/4 turn. Repeat the 1/2 turn clockwise and 1/4 turn counterclockwise until the depth desired is reached or the entire hole has been taped which is easy to tell as there will be no more pressure resistance on the 1/2 turn clockwise cutting motion. The tape can then be backed out. Some soft materials like aluminum that are thin do not need the counterclockwise backout cuts an can be tapped simply by continuing to turn clockwise. But as thickness and hardness of the material increases this step will be needed. A final note is that if you try to tap without the counterclockwise backup cut for quite a few turns and then find you need to use it as the cutting it getting very hard, it may be impossible to do the backout cut. So it is better to use the backout cut if unsure. 5d3e1a493021cf3d3ce5e42f436347c327b53e36 0 255 358 357 2013-05-12T02:51:55Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:HBjelkhagen.jpg]] Dr Hans I. Bjelkhagen, professor of Interferential Imaging Sciences, with North East Institute for Higher Education, Wrexham, at the Centre for Modern Optics located in OpTIC Technium in North Wales, UK. He received his PhD degree in 1978 from the Royal Institute of Technology in Stockholm, Sweden. There he developed methods for recording interferometric holograms and performed holographic nondestructive testing for the Swedish car and airplane industry, e.g., VOLVO and SAAB. In addition to industrial applications of holography, Dr Bjelkhagen specialised in medical and dental holographic recordings. Dr Bjelkhagen has developed a holographic recording system for dental casts. The equipment: HOLODENT SYSTEM was produced and marketed by Dentatus International AB in Sweden. He has also invented and patented a special method to detect caries lesions (tooth decay) at an early stage based on laser fluorescence. Currently, a quantitative clinical system based on that patent is being developed and marketed by INSPEKTOR Research Systems bv in Amsterdam, the Netherlands. In 1983, he joined CERN in Geneva, Switzerland, where he was involved in development of bubble chamber holography. A year later he participated in an international team working on neutrino physics experiments recording holograms in the 15-foot bubble chamber at Fermilab in Batavia, IL, USA. Between 1985-1991 he was at Northwestern University, Evanston, IL, working on medical endoscopic applications of holography. He developed methods of recording in-vivo holograms at the tip of a special fibre-optic endoscope. Dr Bjelkhagen has been involved in the development of a large autostereoscopic computer display system when working for American Propylaea Corporation and Intrepid World Communications in Michigan. The project was carried out between Propylaea and US Army Tank Command, Warren, MI, through a CRDA (A Cooperative Research and Development Agreement). The work resulted in a prototype based on a 30" by 50" projection HOE and an array of single-lens video projectors and run by Silicon Graphics ONYX computers. During the last ten years, Dr Bjelkhagen has been most recognized for his work in colour holography, holographic recording materials and Lippmann photography. Dr Bjelkhagen has been able to demonstrate that high-quality full-colour holograms recorded in "white" laser light (combined RGB light from three laser wavelengths) could be stored in a single-layer ultra-high-resolution silver halide emulsion. In December 1997 Dr Bjelkhagen was invited by Professor Nicholas Phillips to join him at the newly established Centre for Modern Optics at De Montfort University, Leicester, in England. There he continued his research on 3D imaging, colour holography, colour HOEs, holographic recording materials, and Lippmann photography. Currently, a new optical variable device (OVD) based on the one-hundred-year-old Lippmann photographic colour recording technique is being developed. The application is in the field of optical document security. Individually recorded OVDs, similar to reflection holograms, can be applied to documents, such as, passports, ID-cards, driver’s licenses, etc. At the Centre for Modern Optics he has been involved in projects supported by companies, such as, SAMSUNG and SHARP. In addition to his scientific 3D coherent imaging Dr Bjelkhagen is a well-known holographer who has recorded many holograms for 3D display purposes. From his early years in holography he has been involved in large-format, high-quality display holography both pulsed and cw laser holography. He has recorded many unique art objects, such as, e.g., the Swedish Coronation Crown of Erik XIV (from 1561) in 1974 and the Chinese Flying Horse from Kansu (from 100 A.D.) at an exhibition in Stockholm in 1976. Dr Bjelkhagen has been working with several famous artists, for example, Carl Fredrik Reuterswärd, creating holograms exhibited in many art museums and art galleries around the world. Dr Bjelkhagen has specialized in pulsed display holograms, in particular, holographic portraits. He has recorded holograms of many people the most famous one being President Ronald Reagan, a portrait recorded May 24, 1991. This is the first and, so far, the only holographic portrait recorded of an American president. One copy of the holographic portrait is in The National Portrait Gallery of the Smithsonian Institution in Washington DC. When Dr Bjelkhagen was working in the USA in the 80s and 90s, he started two holographic companies together with two of his colleagues in Chicago. One company was HOLICON Corporation, a company specialised in large-format pulsed holography and portraiture. Among the interesting projects can be mentioned a promotional project for Bristol-Myers Squibb Company: "The Gallery of the Pathogenesis of Atherosclerosis" using hologram of microscopes through which arteries could be studied. After the campaign was over, the holograms were donated by Bristol-Myers Squibb to museums in the USA, for example, the Museum of Science and Industry in Chicago, where the holograms are still on display. HOLICON was also financially responsible and provided equipment for recording the 1991 holographic portrait of President Ronald Reagan which took place at Brooks Institute of Photography in Santa Barbara in California. The other company, Holographic Industries Inc., operated several Lightwave Hologram Galleries, marketing holograms and other holography-related products and located in US cities such as, e.g., Chicago, Detroit, and San Francisco. Dr Bjelkhagen has published over 100 papers in refereed journals and conference proceedings and holds 9 international patents. However, his most important academic contribution is the Springer book on Silver-Halide Recording Materials for Holography and Their Processing. That book considered to be the standard textbook on the subject is now used in many of the universities teaching holography as well as in most worldwide companies producing display holograms. Bjelkhagen is a member of the Optical Society of America (OSA) and a Topical Editor of the society's journal Applied Optics. He is a fellow the International Society for Optical Engineering (SPIE) and the co-chairman of SPIE's Holography Technical Group. He is an Accredited Senior Imaging Scientist and Fellow of The Royal Photographic Society (RPS). Bjelkhagen received the RPS SAXBY AWARD in 2001 for his work in holography. *2004 - present Professor, Interferential Imaging Sciences North East Institute of Higher Education, Wrexham, and Centre for Modern Optics at OpTIC Technium, St. Asaph, Wales *2001 -2004 Professor, Interferential Imaging Sciences, De Montfort University, Leicester, England. *1997 - 2001 Senior Research Fellow, Modern Optics De Montfort University, Leicester, England. *1996 - 1997, Visiting Research Scientist, Lake Forest College, Lake Forest, Illinois, USA. *1994 - 1995, Vice President - Research & Development, American Propylaea Corp., Birmingham, Michigan, USA. *1992 - 1994, Visiting Professor, University of Münster, Germany. *1985 – 1992, Associate Professor, Biomedical Engineering, Northwestern University, Evanston, Illinois, USA. *1985, 1991, Associate Professor, Applied Photonics, Louis Pasteur (6 months each University, Strasbourg, France. *1984 1985, Visiting Research Associate, Fermi National Accelerator Lab, Batavia, Illinois, USA. *1983 1984, Visiting Research Associate, CERN (European Organization for Nuclear Research), Geneva, Switzerland. *1978 1983, Associate Research Professor, Production Engineering, Royal Institute of Technology, Stockholm, Sweden. *1969 1978, Research Assistant, Production Engineering, Royal Institute of Technology, Stockholm, Sweden. Swedish citizen, UK resident, US Green Card Holder, Date of Birth: March 9, 1945, Stockholm, Sweden. 7a944325261a7a59821e9f838a2f8cbfea485bf2 0 256 360 359 2013-05-12T02:51:55Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki The color of a hologram can change as the humidity changes. Efforts have been made to epoxy glass plates to the back, glue Oracal to the back and coat the back with cyanoacrylate glues. Jeff Blyth offers a chemical method: ---- One way to stop something breathing is to strap it up tightly. The easiest way to do this is to strap it up with chromium oxygen bonds. Inevitably strapping up leads to contraction. A bonus is that using dichromate can lead to a more hydrophobic gelatin. To get a longer replay wavelength than the 532nm pulse I suppose this is a bit awkward. Shooting the plates in a very dry state helps. The processing chemistry can also help but I appreciate that this must not reduce brightness. Jeff ---- The answer I think is to thoroughly post harden the gelatin for ever. So put a test hologram in a solution of ~5% ammonium dichromate, squeegee off excess drips, blow dry it ,and leave it out in sunshine all day. If you leave it like this without rinsing it will be extremely resistant to any future print out but it might be prudent to rinse out any soluble salts. This post hardening procedure will cause some final but permanent contraction so you would just need to do tests to compensate by adjusting the swelling state for your initial laser exposure of course. My tests on this method allowed the pictures to be viewed in or out of water. So your customers could then view the holograms underwater in their swimming pools ! Jeff ---- Yes I am glad to report a successful experiment last night that left sunlight completely out of it. I took 2 bright bleached Denisyuk holograms, one on a BB640 plate and the other on a Slavich PFG-03M The plates were first dipped vertically into a solution of 7% ammonium dichromate in DI water so that they were only partially covered . After about 2 minutes they were wiped and the dipping solution had 1 % glycerol added to the 7% ammonium dichromate so that other sections of the plates were then treated with this solution. Finally a fresh 7% ammonium dichromate solution was prepared with 2% conc. sulphuric acid. So I finished up with 4 striped sections on a plate. 1) Untreated 2) 7% Ammonium dichromate in DI 3) 7% Ammonium dichromate in DI + 1% glycerol 4) Ammonium dichromate in DI + 2% conc sulfuric acid. Plates were blown in cool air till touch dry and then placed in a preheated oven at 110 C for 12 hours. Then plates were both cooled and washed in cold running tap water for 2 minutes and then dried. Results: Dry plates Stripes 1,2, and 3 showed bright images with no indication of loss of brightness except perhaps stripe (3) may have lost a little. Stripe (4) was completely ruined and out of the running. Plates soaked for 10 minutes in tap water at ~20C. Stripes 2 and 3 showed good clear images still. The BB640 plate had changed color from yellow green to light orange. The PFG-03M had changed hardly at all!... from light yellow to golden yellow. (In view of the notorious softness of this brand it was a surprise to find it had hardened up even better than the BB640 ) So this hardening method does effectively strap up the gelatin film so tightly that it cannot “breathe” and change its color with ambient humidity. Note: This was done on bleached finished holograms. It cannot be used on unbleached reflection ones, the colloidal silver would have to be converted to AgBr first. Jeff 1dc28afe34e9c033367833bcd2ba0d12f3a564bb 0 257 362 361 2013-05-12T02:51:56Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:HSilver.jpg]] Harriet Casdin-Silver is a pioneer of art holography in the United States and was an important figure in the development of installation art and technological art in the 1960s. Casdin-Silver’s work is internationally recognized and has been exhibited for over 25 years in museums, galleries, and universities through the Americas, Europe, and Asia. She has not only set aesthetic standards for holography but also stretched the scientific boundaries of the medium. Casdin-Silver was the first artist to develop frontal-projection holograms, the first to explore white light transmission multi-colored holograms, and the first to exhibit outdoor, solar-tracked holograms. Casdin-Silver began her artistic career in the 1960s as a painter and quickly moved into multi-media and technological images. In 1968, she made her first holograms, becoming one of the first artists to work in this media. Casdin-Silver’s early work focused on both abstract and object-based images; by the late 1970s, Casdin-Silver began exploring the human figure, in particular the female body. At the same time, the artist began to combine holography with other media to create installation pieces. More recently, Casdin-Silver’s work focuses on the issues of feminism, the human form, the aging process, death, and issues of identity. -- Nick Capasso, Curator, Harriet Casdin-Silver: The Art of Holography, a retrospective at the DeCordova Museum and Sculpture Park CASDIN-SILVER, American, artist; born Feb 10, 1925, died Mar 10, 2008. Education: University of Vermont, Burlington, Columbia University, New York, New School for Social Research, New York, Cambridge Goddard Graduate School, Cambridge. Career: Artist in residence, American Optical Research Laboratory, Framingham, Mass, 1968-73; Ukranian Institute of Physics, Kiev, 1989; Asst. Professor of Physics (Research), Brown University, Rhode Island, 1974-78; Fellow, Center for Advanced Visual Studies, MIT, 1976-85; Consultant, Rockefeller Foundation Arts Program, 1980-81; Visiting lecturer, Royal College of Art, London, 1992, also University of Ghent, Belgium; Prof., Mass College of Art and Design, Boston, 1999; Presenter, SKY ART Conf., Delphi & Ikaria, Greece, 2002; also independent artist Rockefeller Foundation Awards, 1978-79, 1980-82, Lifetime Achievement Award for Art In Holography (Univ. of Nottingham, UK), 1996, Visible Republic Award for public art, 2001, Shearwater Foundation Award for excellence in Holography, 1987, 2001. Exhibitions: Documenta6, Germany 1977, Vienna Biennale, Austria, 1979, São Paolo Bienal, Brazil, 1985, The Art of Holography (Retrospective), DeCordova Museum, USA, 1998, Celebration of Aging (audio-holographic installation), Boston 2000, Univ. of Rhode Island, 2001, Is Freedom Visible? Massachusetts Statehouse, 2002, Museum of Afro-American History, 2003, We Are Here, South Station Concourse, Boston, 2002. Publications include: My First 10 Years as Artist/Holographer, Leonardo, 1989, Holographic Installations, Sculpting With Light, Sculpture, 1991, "Putting Guts into the Machine", Women's Review of Books, 2004. Address: 99 Pond Ave. #403, Brookline, MA, 02445 (Home); 51 Melcher St., 5th Floor, Boston MA, 02210, USA (Studio). 849b9d41e88f4e2f06d4fca9f4138fa6ec5be16c 0 258 364 363 2013-05-12T02:51:56Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki == Hart Perry == During the last 30 years working as a filmmaker, Hart Perry has carved out three distinct reputations: social and music documentarian, cameraman and artist. In 1969 he was the youngest cameraman at the legendary Woodstock music festival and in 1970 he directed his first music video, "Alice Cooper." In 1977, he was the principal cinematographer of the award-winning documentary "Harlan County, U.S.A." During the 1970s and 1980s, Perry was a innovative force in the development of holographic movies (Integral holographic stereograms). Working with a grant from the National Endowment for the Arts in 1977, he built the second optical printer for producing holographic movies in the world. As President of the Holographic Film Company (New York), he worked on commercial applications for holographic movies in the areas of advertising and portraiture. In addition, he was the Director of the Cabin Creek Center's Artist-in-Residence program, funded by the National Endowment for the Arts and the New York State Council on the Arts. This program represented the innovative collaborations of holographies with visual artists, sculptors and dancers. In creating holographic movies, Mr. Perry converted 16mm film footage to holographic film to capture both motion and dimension. The holographic film was then wrapped inside a Plexiglas cylinder and illuminated for viewing with a normal light bulb. This process was invented by Lloyd Cross in 1972. His holograms of computer generated images produced in the early 70s were innovative and have been widely exhibited in museums and art galleries. In addition, he produced holograms for Salvador Dali, Milton Glazer, Mabou Mimes, Agam and other artists. [http://www.perryfilms.com/hart.html] 775a4f686669bc313f7522671f2aa59579dcc242 12 259 366 365 2013-05-12T02:51:56Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki To get help on editing the HoloWiki look [[Help:Editing|here]]. To get help on holography you can ask questions [http://www.holographyforum.org/phpBB2 here]. To use Google to search this site add "site:www.holographyforum.org" to any google search. [http://www.google.com Google] 87b1ecee048787326cad92e32d4c9535f3cbc0b2 12 260 368 367 2013-05-12T02:51:56Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki This Wiki uses a simple markup to allow for special formatting. Edit this page to see how the things below were done. Besides the buttons at the top of a edit form, there is additional formatting such as bullets for lists: * item * something else * and another thing numbered lists: # first # second # last ====headings==== (more equal signs mean smaller heading) Tables: {| | 1 || 2 || 3 |- | 4 || 5 || 6 |} Boxed text (indent with a space) Span tags for <span style="text-decoration: underline">real</span> <span style="background: yellow">power</span> users. And, lots more. See here for details: [http://languagemachine.sourceforge.net/mediawiki.html media wiki grammer] [http://meta.wikimedia.org/wiki/MediaWiki_User's_Guide:_Editing_overview Media Wiki's Overview on Editing from the Users Manual]. Here is a [[Sandbox]]. Just to try and edit what ever you want. c9b6c1de3a5b59754e21d69bb6d12b9bf03e139e 0 261 370 369 2013-05-12T02:51:56Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki A timeline of Holography is available [[Concise History|Here]]. [[Anecdotes]] Stories from the trenches [http://www.holography.ru/histeng.htm Holography.ru Early History of Holography] [[Books]] 57531702dc91dff5854bf3e9741517c4755f6bf3 0 262 372 371 2013-05-12T02:51:57Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki The Holowiki is the off-shoot of the [http://www.holographyforum.org Holography Forum]. Since we started we have generated more than 30,000 posts and found we were talking about some of the same things again and again without reference to the information we had dug up the last time we read it. [[Phil Edelbrock]] came up with the great idea of starting a "small wiki". What you see now has taken 100's of hours of work looking through old posts and writing new information. The Holowiki logo in the upper right corner was drawn in pencil by Tim ???? in Napa, CA. It was drawn life size then scanned and reduced. The Light Bulb Logo on the main page was the brain child of [[Phil Edelbrock]]. He took three photos of his HeNe laser shining on a light bulb and used photoshop to shift the colors to three make it look like 3 different lasers. When the three images were superimposed the lightbulb was white without adjustment. He then wrote the code for the positioning of the titles on the main page. [[What is a Wiki?]] dc5e14ce94779cb6ab267825de7a069f47f4e426 0 263 374 373 2013-05-12T02:51:57Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Colin Kaminski]] is the administrator of the HoloWiki. If you would like to help him with administration please contact him. 25c965db19299d5223150a5e91f957a4a66a4fb1 0 264 376 375 2013-05-12T02:51:57Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Sharing information is the reason that a group of holographers has joined together. It started at the [http://www.holographyforum.org Holography Forum]. The holography forum was created on July 1st 2002, since that time we've posted more than 30,000 posts. The forum and HoloWiki Director is [[Colin Kaminski]]. We also have created a sister organization called the [http://www.pcgholography.com PCG] now run and maintained by [[Michael Harrison]]. It's purpose is to carry our momentum off the web and into the real world. We do this through meetings and outreach. 981e9e0bd1c3b56799e1992bcb39fdcc10249c5b 0 265 378 377 2013-05-12T02:51:58Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Unless otherwise stated by the author the copyright for the HoloWiki will be GNU Public Documentation License as follows: Copyright (C) 2000,2001,2002 Free Software Foundation, Inc. 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. 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Retrieved from "http://www.holographyforum.org/HoloWiki/index.php/Copyright" 675d9b98a219bca068f6ccc95fa6fdbd2d164f84 0 266 380 379 2013-05-12T02:51:58Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki This is a resource created by a bunch of holographers. We try to keep it accurate but use your own judgment. If we say it is impossible then it might not work. If we say it is easy then it might be possible. :-) 1944d46b3604751ff1ea4f270be3c6f5b2d9c3fb 0 267 382 381 2013-05-12T02:51:58Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Make sure your edit is needed! Using double squar brackets around a word will make a new page with that name or link to an existing page. Using "===section Title===" Makes sections and a contents section on a page. Using single square brackets makes an external link to a web site. 9880fa78c631a72fb1167cb119d0071095cfdb6e 0 268 384 383 2013-05-12T02:51:58Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Any user who defaces the HoloWiki or demeans another person will be blocked. 66e91aab2263210847e22770e1b481b35b6c4657 0 269 386 385 2013-05-12T02:51:58Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki This site is run by [[Colin Kaminski]] as a web based Holography information source as part of [http://www.holographyforum.org www.holographyforum.org]. It is really not very expensive to run but if you wish to donate to the cause you can through PayPal. The cost of maintaining the Wiki part of this site is $25 per year above the $20 per month to run the Holography Forum. Click this link to donate $20 to the Holography Forum. [https://www.paypal.com/xclick/business=colinsk@pacbell.net&item_name=Holography+Forum+Donation&amount=20.00&no_shipping=1&return=www.holographyforum.org/thankyou.html&currency_code=USD Donate with PayPal] The best donation you can give the HoloWiki is your time. Any time you spend writing and editing will help every holographer to have a better understanding of our craft. 552d67ababccd9466841fa17ec7d0e5a4804276b 0 270 388 387 2013-05-12T02:51:59Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:CIEDiagram.jpg]] Holograms need a material to record interference fringes. There are many materials that can record fringes. '''[[Silver Halide Chemistry]].''' Theory and Practice of Making Silver Halide Plates and Development. '''[[Silver Film Comparison Chart]]''' A quick comparison of the qualities of different commercially made films. '''[[Dichromated Gelatin Chemistry]].''' Theory and Practice of DCG Plates and Development. '''[[Polymer Film and Processes]]'''. Many commercially sold holograms are made from photopolymers. '''[[Photoresist]]'''. Taken from the electronics industry, this material can make relief holograms for embossing. '''[[Coating Methods]]'''. Coating Gelatin on to a glass plate is an art in itself. '''[[Crystals]]'''. There are many crystals that can record an image. The cost and exposure energy required is very high so they are not often used for holography. '''[[Embossed Holograms]]'''. These are like the holograms seen on credit cards. '''[[Gelatin]]'''. Used as the suspension medium to hold light sensitive particles. [http://en.wikipedia.org/wiki/Hologram#Materials Wikipedia's summary of Holographic Recording Materials] [http://en.wikipedia.org/wiki/Periodic_table_%28standard%29 Periodic Chart of the Elements] '''[[Books]]''' 155e35968057a437052d49b3dc62bd4bc0c9f685 0 271 390 389 2013-05-12T02:51:59Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki See [[Setups]] for more information on making these types of holograms. ===A Hologram Defined=== hol·o·gram (hŏl'ə-grăm', hō'lə-) n. A [[Diffraction|Diffraction Pattern]] which, when properly lit, produces a three-dimensional image. Typically, holograms are made using a laser as a light source and and a very high resolution film or glass plate to record the diffraction pattern resulting from interference between light coming directly from the laser and light reflected from the object. ===Transmission hologram=== This was the one of the first holograms made. A transmission hologram is made when the reference beam and light from the object enter the recording material from the same side. The recorded interference fringes form a transmission grating which diffracts light passing through the hologram. Properties include: * looks like a blurry rainbow image when viewed with white light * viewable as a sharp image only by shining laser light through the hologram * recording material requirements are more relaxed (less resolving power is needed) * simple set-up * greater depth of the scene is possible * the scene can be projected by shining a collimated laser beam through the hologram ===Reflection hologram=== A reflection hologram is made when the reference beam and light from the object enter the recording material from opposite sides. Properties include: * viewable in regular light * very simple Denisyuk style setup can be used * finished hologram is monochromatic (a single color) for each laser color used * color can be shifted by pre or post shrink/expanding recording material ===H1 to H2 copies=== H1 refers to a first generation (master) hologram. H2 refers to a copy made from the H1. H1s are usually transmission holograms and H2s are usually reflection. They may use different recording materials. Properties include: * Somewhat complex setup requirements * Objects can be made to appear to be coming out of the plate towards the observer * Once a usable master H1 is made and the setup constructed, many copies can be produced easily ===Rainbow Holograms=== Rainbow holograms are transmission holograms which are produced in such a way as to be viewable in regular white light. Depending on the viewing angle, the color changes (hence the term rainbow) Properties include: * perspective information is lost in one axis (for example, you may not be able see a change in perspective when looking from above or below) ===Open-Aperture Transmission Hologram=== An open-aperture transmission hologram is simply a transmission hologram the has the image very close to the film plane and is designed to be viewed in white light. Properties include: *White light viewable. *Image blurs colors as the image move in front of, or behind the film plain. *2 cm usable depth of field. *The image is achromatic. ===Multiplexed holograms=== Multiplexed holograms store many different holograms on one piece of film usually as multiple exposures. Properties include: * simple animations are possible * diminishing quality as more holograms are stored ===Edge Lit Holograms=== Edge Lit Holograms have the reference beam entering the plate from one edge instead of one face. This allows the illumination to remain hidden from the observer and makes for a fairly compact display. *They are difficult to make. [http://www.media.mit.edu/spi/SPIPapers/ryder/thesis.pdf Edgelit holography:Extending Size and Color] by Ryder Sean Nesbitt ===Embossed Holograms=== Embossed holograms are made by forming a rainbow transmission hologram in thermoplastic and bonding it to a mylar mirror. It is the kind of hologram seen on credit cards. Properties include: * very low per-unit cost when mass-produced * shallow hologram depth (usually just a few millimeters) * durable and flexible * mass production can use existing equipment and technology (e.g. CD production) ===Pulsed Holograms=== Pulsed Holograms can be either transmission or reflection. The key difference is the pulsed laser emits a short, powerful pulse of light rather than a continuous beam. This pulse (about 20ns) is short enough to stop moving objects and make an image. Even bullets can be stopped with the correct setup. Most often used for portraits. * The flash photography of holography * Stability requirements are greatly diminished, allowing for holograms of people, melting ice, flowers, animals, etc. to be made * Pulse lasers are very expensive * Setup and testing can be tricky and dangerous See [[Tips for Pulsed Ruby Holograms]]. ===True Color Holograms=== [[Image:CIEDiagram.jpg]] True color holograms are a variety of reflection hologram made with more than one laser color. There have been good true-color holograms made with two, three and four colors of lasers. The resulting hologram displays the same colors as the original object. * Since true color holograms are multiplexed holograms, recording material need to be capable of holding a lot of information * Lasers and equipment can be expensive and tricky to set up [http://www.ultimate-holography.com/GB/galerieanglais2Color.html See examples by Yves Gentet] 85b7157da9bc9b9b9a1d66f8a1beed793daef9dd 0 272 392 391 2013-05-12T02:51:59Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ===Diffraction gratings=== ===Reflection Holographic Optical Elements=== ===Transmission Holographic Optical Elements=== e6f08a62e99e20230fd40c44e33927251a76c6d3 0 273 394 393 2013-05-12T02:52:00Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- This is a dictionary of Holographic terms. It has been compiled by the members of the Holography Forum for the last few years. Additions and suggestions are welcome. Further reference can be found in the [[Books]] section. ---- Things to add... Wiener prism Sagitta Sagittal Plane Tangental Plane Kerr Medium KTP, etc YAG Nd:YAG Nd:Glass Flash Lamp KLM Ti:Al2O3 Cr:LiSAlF6 - CrLiSAF AlGaInP diode Uranium Nitrate - chemical used in toners and developers. Time-Smear plate (plate) holder settling settling time splitter - see beam splitter expose exposure table - See optic bench safe light (development/chemical) tray developer rinse Photoflo object (when used in terms like 'object beam') reference squeegee play back TEA swell/swelling (of emulsion) etalon first surface mirror HOE (holographic optical element) immersion lens Liquid lens Nd:YAG laser DPSS laser Pulsed laser Q-Switched laser CW (continuous wave) Diode Laser denominator numerator Phase hologram reversal bleach rehaloginating bleach physical development Colloidal development Printout post developing Blink reflex (also known as aversion response) is the closure of the eyelid or movement of the head to avoid an exposure to a noxious stimulant or bright light. A carcinogen is an agent potentially capable of causing cancer. A continuous wave (cw) is the output of a laser which is operated in a continuous rather than pulsed mode. A controlled area is an area in which the occupancy and activity of those present is subject to control and supervision for the purpose of protection from radiation hazards. The cornea is the transparent outer coat of the human eye, covering the iris and the crystalline lens. The cornea is the main refracting element of the eye. Diffuse reflection is the change of the spatial distribution of a beam of radiation when the beam is reflected in many directions by a surface or by a medium. An embedded laser is enclosed in a laser system and has an assigned class number higher than the inherent capability of the laser system. The laser system's lower classification is appropriate because of the engineering features that limit accessible emission. An enclosed laser is contained in a protective housing. Opening or removing the protective housing provides additional access to laser radiation above the applicable MPE. (An embedded laser is a type of enclosed laser.) Erythema is the medical term for redness of the skin due to congestion of the capillaries. Frequency Doubling is a phase-sensitive process where an input (pump) wave (usually a laser beam) can generate a wave with twice the optical frequency in the medium with a similar direction. [http://www.rp-photonics.com/frequency_doubling.html source] Hurter-Driffield curve is a graphical curve formed by plotting the film density (log of opacity) versus the log of exposure time. Sometimes goes by other names such as characteristic curves, D–logE curves, and D–logH curves. Infrared radiation (IR) is electromagnetic radiation with wavelengths that lie within the range 0.7 mm to 1 mm. Intrabeam viewing is the viewing condition in which the source subtends an angle at the eye which is equal to or less than amin, the limiting angular subtense. In simpler terms, the eye views or is exposed to a laser beam directly. This category includes most collimated beams and so-called point sources. The iris is the circular pigmented membrane that lies behind the cornea of the human eye. The iris is perforated by the pupil. A joule (J) is a unit of energy (1 joule = 1 watt per second). A laser is a device that produces an intense, coherent, directional beam of light by stimulating electronic or molecular transitions to lower energy levels. Laser is an acronym for light amplification by stimulated emission of radiation. A macula is the small, uniquely pigmented and specialized area of the retina. Maximum permissible exposure (MPE) is the level of laser radiation to which a person may be exposed without hazardous effect on or adverse biological changes in the eye or skin. The ocular fundus is the back of the eye. The ocular fundus may be seen through the pupil by use of an ophthalmoscope. Optical density (Dl) is the logarithm to the base ten of the reciprocal of the transmittance: OD = log10(Ei/Et), where OD = optical density, Ei = incident beam irradiance (W/cm2) worst case exposure, and Et = transmitted beam irradiance (MPE limit in W/cm2). Power is the rate at which energy is emitted, transferred, or received. Protective housing is an enclosure that surrounds a laser or laser system, preventing access to laser radiation above the applicable MPE level. Pulse duration is the duration of a laser pulse, usually measured as the time interval between the half-power points on the leading and trailing edges of the pulse. A pulsed laser is a laser that delivers its energy in the form of a single pulse or train of pulses. A Q-switch is a device that produces very short (~10–250 ns), intense laser pulses by enhancing the storage and dumping of electronic energy in and out of the lasing medium. A Q-switched laser is a laser that emits short (~10–250 ns), high-power pulses by means of a Q-switch. Radiance is radiant flux or power output per unit solid angle per unit area. Reflection is the deviation of radiation following incidence on a surface. The retina is the sensory membrane that receives the incident image formed by the cornea and lens of the human eye. The retina lines the inside of the eye. Second-Harmonic Generation - See frequency doubling. A spectator is an individual who wishes to observe or watch a laser or laser system in operation and who may lack the appropriate laser safety training. Specular reflection is a mirrorlike reflection. Ultraviolet radiation (UV) is electromagnetic radiation with wavelengths smaller than those of visible radiation. A viewing portal is an opening in an experimental system, allowing the user to observe the experimental chamber. All viewing portals and display screens included as an integral part of a laser system must incorporate a suitable means to maintain the laser radiation at the viewing position at or below the applicable MPE (eye safe) for all conditions of operation and maintenance. It is essential that the material used for viewing portals and display screens not support combustion or release toxic vapors following exposure to laser radiation. Visible radiation (light) is electromagnetic radiation that can be detected by the human eye. This term is commonly used to describe wavelengths which lie in the range 0.4 to 0.7 mm. A watt (W) is the unit of power or radiant flux (1 watt = 1 joule per second). A wavelength is the distance between two successive points on a periodic wave which have the same phase. d5e54659f41c9ff4ca0b756d25ab9f307d2bae8f 0 274 396 395 2013-05-12T02:52:00Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Please add any links you have found useful. Try to alphabatize by Site title. '''[[Books]]''' can be found [[Books|here]]. ===Links to Holography Instruction=== *[http://home.comcast.net/~gakall/holopg/ Amateur Holography] Simple & Low Budget *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.nobel.se/physics/laureates/1971/gabor-lecture.pdf Dennis Gabor's Nobel Lecture, December 11, 1971] *[http://www.holographer.org The Holographer] *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] *[http://amasci.com/amateur/hand1.html Hand Drawn Holograms] *[http://www.holoworld.com/holoportraits/index.html Hand Made Hologram Portraits] An Amateur/Hobbyist Guide *[http://www.holostudios.com/holohelper/index.html Hologram Basic Principles] by Jason Sapan *[http://www.holokits.com/newsarticles.htm Integraf's Articles] *[http://www.focalimage.com/public/kaveh-PhD.pdf Kaveh's Thesis] *[http://www.buildcoolstuff.com/gallery/holograms.html Laser Pointer Holograms] *[http://www.repairfaq.org/sam/lasersam.htm Laser Sam's FAQ] The best source of laser related information on the net. *[http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html MIT Spring 2002 Holography course] *[http://www.holo.com/holo/book/book.html Practical Holography] by Christopher Outwater & Van Hamersveld *[http://www.holography.ru/techeng.htm Russion Holography 25 Holography Lessons] *[http://www.dragonseye.com/blog/categories/2-Tutorials Holography Tutorials] by Michael Harrison *[http://www.physics.ohio-state.edu/~kagan/holography/index.html Holography course at Ohio State] *[http://teched.vt.edu/gcc/CurriculumMaterials/HoloProject/HTML/index.html Virtual Holography course at Virginia Tech] *[http://www.ph.ed.ac.uk/~wjh/teaching/mo/holography.html University of Edinburgh] *[http://www.3dimagery.com Nuts to bolts online descriptions for hobbyist] *[http://geola.lt/download/synfography_virtual_scene_setup.pdf Synfography basics - virtual scene setup for Geola's colour holographic printing] ===Links to Holography Supplies and Tools=== ====Turnkey Equipment==== *[http://www.myholostudio.com/ Analogue holography] {Complete holography studios} *[http://geola.lt/show.php?lang=eng&cont=holo_index&lside=holo_index_left Digital holographic printing - Synfography] {Complete digital solutions} ====Electronics==== *[http://www.digikey.com DigiKey] {Electronics} *[http://www.goldmine-elec.com Gold Mine Electronics] *[http://www.allelectronics.com/ All Electronics] {Electronics} *[http://www.alltronics.com Alltronics] {Electronics} *[http://www.oatleyelectronics.com/ Oatley Electronics] {Electronics} *[http://www.mouser.com/Mouser Mouser] {Electronics} ====Film and Chemistry==== *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.laserreflections.com Laser Reflections] {Film} *[http://www.slavich.com Slavich] {Film, Plates and Chemistry} *[http://www.geola.lt/eshop/index.htm Geola] {Certified Slavich film and plates made for Geola distribution network, Chemistry} *[http://www.forthdimension.net Forth Dimension] {Film and Supplies} *[http://www.photoformulary.com Photographer's Formulary] {Chemistry} *[http://www.sigmaaldrich.com/ Sigma Aldrich] {Chemicals} *[http://perso.wanadoo.fr/holographie/GB/index.html Ultimate Film] {Film} *[http://www.abra-electronics.com Abra Electronics] {Isopropyl Alcohol} *[http://www.colourholographic.com Colour Holographics] {BB Plates - Red, Green, Blue, Pan} *[http://www.filmotec.de/Produkte/produkte.html Filmotec] {ORWO - Red, Green, Pan in works} *[http://www.fujihunt.com/fuji/fhweb2004.nsf/pagesbykey/Holo%20products?OpenDocument Fuji] {Pan said to be discontinued} ====Kits==== *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.geola.lt/show.php?lang=eng&cont=phot_en_kit&lside=phot_index_left Geola] {Holography supply refill kit} ====Lasers, Parts and Supplies==== *[http://www.optima-optics.com Optima] {Laser Diode Parts} *[http://www.nvginc.com NVG Inc.] {Laser Diode Parts} *[http://www.mi-lasers.com/index1.html Meredith Instruments] {Used Gas Lasers} *[http://www.roithner-laser.com/ Roithner] {Lasers and diodes} *[http://www.cnilaser.com/ CNI Laser] {DPSS Lasers}] *[http://www.lasersurplus.com/ Laser Surplus Sales] {Used Lasers} *[http://www.innolas.co.uk/ Innovative Laser Technology] {Lasers and parts} *[http://www.geola.com/ Geola] {High energy pulsed lasers, Holographic studios} ====Optics and Table Supplies==== *[http://www.thorlabs.com Thor Labs] {Optics} *[http://www.edmundoptics.com/us/onlinecatalog/browse.cfm Edmund Optics] {Optics} *[http://www.imagesco.com ImagesCo] {Supplies and inexpensive optics} *[http://www.surplusshed.com Surplus Shed] {Surplus Optics} *[http://www.murni.com/kit_0.htm Coulter Telescopes] {Inexpensive Collimating Mirrors} *[http://www.abrisa.com/index.asp Abrisa] {Glass Products, Dichroic Mirrors} *[http://www.lenoxlaser.com/ Lenox Laser] {Piinholes} *[http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=5646 Harbor Freight] {Magnetic Bases} *[http://www.use-enco.com/CGI/INSRIT?PMAKA=625-0300&PMPXNO=946102&PARTPG=INLMK3 ENCO] {Magnetic Bases} *[http://www.geola.com/ Geola] {Optics for pulsed holography} ====Robotics==== *[http://www.solarbotics.com SolarBotics] {Robot Technology} ====Surplus and Other Stuff==== *[http://www.sciplus.com American Science Surplus] {Surplus Parts and Cool Stuff} *[http://www.spsenergy.com/index.htm SPS Energy] {Solar Cells as Light Meter Probes} *[http://www.fgsi.com/oracal.htm Oracal] {instead of black paint for reflection holos #651} ====Tooling and Machining==== *[http://www.reidtool.com Reid Tool] {Tooling supplies} *[http://www.mscindustrial.com MSC Industrial] {Raw Metal and Machining Supplies} *[http://www.mcmaster.com McMaster Carr] {Raw Metal and Machining Supplies} ====Tools==== *[http://www.use-enco.com Enco] {Tools} ====Technical==== *[http://www.moshier.net/rtd-readme.html Thermistor calibration] ===Links to Amateur/Individual Holographers=== *[http://www.techsoft.no/holography/ronny_anderassen.htm Ronnie Anderassen] *[http://www.anait.com/ Anait] *[http://members.shaw.ca/holopix/My_holograms.html TomB] *[http://www.holography.demon.co.uk/ Margaret Benyon] *[http://rudieberkhout.home.mindspring.com/ Rudie Berkhout] *[http://cabd0.tripod.com/holograms/ Jeff Blyth] *[http://universal-hologram.com/index.htm Greg Cherry] *[http://web.mit.edu/museum/lightforest/lightforest.html Betsy Connors] *[http://www.holoworld.com/ Frank Defreitas] *[http://www.jfairstein.com/holoindex.html Jon Fairstein] *[http://www.hologramm.ch.vu/ Floh] *[http://webhome.idirect.com/~hgdesign Howard Gerry] *[http://www.ghisays.net Andres Ghisays] *[http://universal-hologram.com/nini%20gorglione.htm Nancy Gorglione] *[http://www.dragonseye.com/blog Michael Harrison] *[http://www.techsoft.no/holography Vidar Hegdal] *[http://www.pearljohn.co.uk/ Pearl John] [http://pearljohn.blogspot.com/ her Blog] *[http://www.bobdbob.com/~protius Tommy Johnson] *[http://www.designerinlight.com Colin Kaminski] *[http://www.holocenter.or.kr/ Juyong Lee] *[http://www.lucente.biz/index.html Mark Lucente] *[http://www.indimensionn.com/page3.html Bill McGarvin] *[http://www.holography.nl/ Kris Meerlo] *[http://www.rotorwave.com/holography.htm Ron Michael] *[http://www.3dimagery.com Steve Michael] *[http://holographics.com.au/ Martina Mrongovius] *[http://www.lasart.com/ August Muth] *[http://www.hololab.com/ Ikuo Nakamura] *[http://www.anamarianicholson.com/ Ana Maria Nicholson] *[http://www.holograms3d.com/ John Pecora] *[http://www.apepper.com/ Andrew Pepper] *[http://www.alchemists.com/visual_alchemy/holography.html Al Razutis] *[http://www.vilamedia.com/gallery.html Doris Vila] *[http://wengam.com/ Wenyon & Gamble] *[http://perso.wanadoo.fr/redlum.xohp/argonlaser.html W's Laser Projects Page] *[http://www.martymouse.net/happyfeet/ Danny Bruza (Danny Bee)] ===Links to Holograms For Sale=== *[http://www.holography.ru/maineng.htm Beautiful Russian Holograms] *[http://www.holograms.bc.ca Royal Holographic Art Gallery] *[http://holographiccenter.com/ Holographic Center] *[http://www.triple-take.com Triple-Take] *[http://www.hologramstore.biz Dragon's Eye Creations] *[http://www.holoshop.nl HoloShop.nl] *[http://www.holoshop.com Holograms & Lasers Intl] *[http://www.geola.lt/show.php?lang=eng&cont=holoindex&lside=holo_index_left Geola - Digital holographic prints - Synfograms - Colour and movement in one] *[http://universal-hologram.com/ Hologram Art] *[http://www.rabbitholes.com/art-gallery/ Holographic Art Prints from Computer 3D and Animation from Leading 3D Artists] *[http://www.rabbitholes.com/order-samples/ Samples kits of Rabbitholes Holograms] ===Links to Professional Holographers=== *[http://www.3dimagery.com Three Dimensional Imagery] Hologram Production Lab *[http://universal-hologram.com/index.htm Cherry Optical] Hologram Production Lab *[http://www.forthdimension.net Forth Dimension] Hologram Production Lab *[http://www.holonorth.com/main.html Holographics North] Hologram Production Lab *[http://www.holographsonmain.com Holographs on Main] Portrait Studio *[http://www.laserreflections.com Laser Reflections] Pulsed Holography Lab *[http://www.zebraimaging.com Zebra Imaging] Hologram Production Lab *[http://www.geola.lt Geola] Synfograms (Geola's digital holograms) - life scene colour imaging with animation *[http://www.rabbitholes.com RabbitHoles Media] Full color digital hologram production ===Organizations=== *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.holography.co.uk/index.shtml Royal Photographic Society] *[http://www.spie.org The International Society for Optical Engineering] *[http://www.IHMA.org International Hologram Manufacturers Association] *[http://www.holographynews.info Holography News - Industry information] 30a3b3abb88157f701f692ed5320165cbe8381dd 0 275 398 397 2013-05-12T02:52:00Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki While holography is a fairly safe activity it is important to understand the materials we are dealing with and treat them with respect. Below we have compiled so information that a holographer will find usefull. It is always growing and is by no means exhaustive. '''[[Laser Safety]].''' Safe practices and some potential hazards of Lasers. '''[[Chemical Safety]].''' Safe practices and some potential hazards of chemical handling. '''[[Power Tool Safety]].''' You can make anything you want but keep your eyes and fingers! '''[[Books]].''' 0fc416ad1fbe7c3064d58cce53ba8519be58c698 0 276 400 399 2013-05-12T02:52:01Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Holography #'''Holograms''' - [[Holograms|Hologram definition and types]] #'''Model Building''' - [[Making Hologenic Objects]] #'''The Lab''' - [[The Lab|Setting up your lab]] #'''Equipment''' - [[Equipment|Equipment used in making a hologram]] #'''Setups''' - [[Setups|Setups - different holographic geometries and configurations]] #'''Computer holography''' - [[Computer Holography|Computer Holography]] #'''Interferometry''' - [[Interferometry|Holographic Interferometery]] #'''Holographic Optical Elements (HOE)''' - [[Holographic Optical Elements|Holographic Optical Elements]] #'''Tips and Tricks''' - [[Tips and Tricks|Tips and Tricks]] #'''Troubleshooting Holograms''' - [[Troubleshooting Holograms|TroubleShooting Holograms]] #'''Displaying and Illuminating Holograms''' - [[Displaying and Illuminating Holograms|Displaying and Illuminating Holograms]] #'''Photographing Holograms''' - [[Photographing Holograms|Photographing Holograms]] #'''Shop Basics''' - [[Shop Basics|How to use shop tools to make mounts and hardware]] #'''Holography Glossary''' - [[Holography Glossary|Holography Glossary]] #'''Books''' - [[Books|Books on Holography]] #'''References''' - [[References|References]] c08819ceedcae219a22a60a7b3a203c1e73deb57 0 277 402 401 2013-05-12T02:52:01Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [http://courses.media.mit.edu/2002spring/mas450/reading/chaptersPDF/index.html Steve Benton's Book Draft] is a good place to start. *[[Learning About Light]] *[[Holography Theory K-12]] *[[Advanced Mathematics for Holography]] *[[Optics Theory]] *[[Color Theory]] *[[3-D Perception]] *[[Art Theory]] *[[Table Design Theory]] *[[Math Help]] *[[Strength of Materials]] *[http://en.wikipedia.org/wiki/Periodic_table_%28standard%29 Periodic Chart] *[[Books]] acb951038f4f412b897d7c9b2b14d9a6eea8e89b 0 278 404 403 2013-05-12T02:52:01Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki #redirect [[Holography Transmission Equations Part I]] d156f21ca0aaf755fb350e2a7da17a174ed75f5d 0 279 406 405 2013-05-12T02:52:02Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== [[Image:InterferenceEQ.gif]] Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: [[Image:SpatialEQ.gif]] (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say. (while I nodded off!) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html [[Image:DiffractionEQ.gif]] They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) [[Image:EdExample1.gif]] Just like it should. If we repeat the above but with m = 2, we get: [[Image:EdExample2.gif]] Unh-unh! sin of an angle can’t be >1! (This is called a [[http://en.wikipedia.org/wiki/Evanescent_wave evanescent]] wave and is not propegated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) [[Image:EdExample3.gif]] (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: [[Image:EdExample4.gif]] Replacing m by 2, [[Image:EdExample5.gif]] When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm [[Image:EdExample6.gif]] Replacing m by 2, [[Image:EdExample7.gif]] This time we can get away by replacing m by 3, [[Image:EdExample8.gif]] So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== fbc0f252fcad12b0d9b6f5edee3cef874f031174 0 280 408 407 2013-05-12T02:52:02Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Back to [[Holography Transmission Equations]] Part One. ==Lateral Magnification== [[Image:LatMagEq.gif]] Lateral Magnification The ratio of the image distance to the object distance in lensed imagery gives the magnification ratio; how big is the image compared to its original size. There are a variety of equations useful for figuring this out, but the simplest to visualize and most like the holographic equation is: [[Image:MagRatioEQ.gif]] When image distance = object distance, magnification ratio = 1:1, the Xerox machine case. In normal picture taking situations, a magnification < 1 or minification takes place; a whole human figure is reduced down to the size of a piece of film or digital chip, with object distance being much greater than image distance. (The denominator in the equation is bigger than the numerator.) A projector has a short object distance compared to its image distance, and the magnification is >1. (Values of numerator and denominator reversed.) Spare me and don’t ask about what happens when an object is at infinity today. This equation refers to the object’s dimensions in the two planes parallel to the holoplate; the longitudinal, or z dimension magnification is an evil equation and is coming next. It relates the original object wavefront curvature, Robj to it’s current position, Rimg. But it can also apply to what happens when the replay wavelength is different than the exposing one. And our little friend m pops up and although not pertinent to the art of H1 masters it is useful for cases when there are multiple image orders, like in a Gabor hologram and its close relative, the zone plate. So if we put our properly exposed and developed laser transmission hologram back in the plateholder where it was made once again like in the examples above, we can calculate: [[Image:MagLatEqEx1.gif]] Image is the same size as the object, since we haven’t moved anything. In the previous section, the image distance was calculated when the reference beam was moved in closer. (Scenario refresher: reference beam in at 45 degrees from infinity or collimated, object plane 100 mm from plate.) Plugging in these object distances in response to moving in the reference beam closer, we get magnifications of these new object distances over 100 mm, since the ratio of wavelengths is unity and so is m. *R ill = 10 m, *R out = 99 mm; *mag = .99 *R ill = 1 m, *R out = 90.9 mm; *mag = .909 *R ill = 100 mm, *R out = 50 mm; *mag = .5 If the object were a 10 by 10 grid of squares 10 mm (1 cm) on a side, the when the reference was at 10 m, the grids would shrink to 9.9 mm on a side; at 1 m, about 9.1 mm squares; and with that very close reference, they drop down to 5 mm mini-squares. Couldn’t there be magnification just like in the lens examples above? There was none possible in the previous hologram because the reference beam during recording was collimated, parallel and coming from infinity, and there is no longer R ill to plug in and let the equation “grow” in replay. Sharp-eyed readers might realize that there is no R ill in the Magnification Equation. But it’s necessary to find R img for the latter, and so the example will include solving for image distance based on reference replay position, then to be plugged into the magnification equation. The parameters for this hologram will be Robj, the point on the object of interest, positioned 10 cm behind the holographic plate; and a Rref of one meter, a distance easily attainable in a sandbox or other small tabletop isolation system, for the reader to verify themselves. It could also be the basis for a Science Fair Project, something on the order of “Experimental Verification of Predicted Object Magnification in Transmission Holograms.” Or just looking at any transmission hologram by moving it back and forth in an expanding illuminating beam will also bring a sense of relevance to these mathematical meanderings. 1/R out = (lambda ill/lambda exp)(1/R obj - 1/R ref) + 1/R ill = (633 nm/633 nm) X (1/100 mm - 1/1000 mm) + 1/1000 mm = 1 X (.01 - .001) + .001 = .01, R out = 100 mm As usual this is the replay configuration that duplicates the recording, so the object distance in the hologram is the same as in real life, and it’s safe to say that magnification is = 1. Halving the reference distance: 1/R out = (lambda ill/lambda exp)(1/R obj - 1/R ref) + 1/R ill = (633 nm/633 nm) X (1/100 mm - 1/1000mm) + 1/500 mm = 1 X (.01 - .001) + .002 = .011, R out = 90 mm compared to R obj of 100 mm yields a magnification ratio of 90/100 = .9 or 90%. This didn’t yield an object magnification of 50%! This equation works exponentially, not linearly. To see where the reference beam needs to come from for a magnification of 50%, (50 mm object distance, or R out) we need to solve for R ill: 1/R out = (lambda ill/lambda exp)(1/R obj - 1/R ref) + 1/R ill = 1/50 = (633 nm/633 nm) X (1/100 mm - 1/1000 mm) + ? = .02 = 1 X .01 - .001 + ? 1/R ill = .011, R ill = 90.9 mm Going in the other direction, doubling the R ill distance, 1/R out = (lambda ill/lambda exp)(1/R obj - 1/R ref) + 1/R ill = (633 nm/633 nm) X (1/100 mm - 1/1000 mm) + 1/2000 mm = 1 X (.01 - .001) + .0005 = .0095, R out = 105.2631 mm, rounded to 105, for a 5% increase in image size. The largest possible virtual image magnification would be when the R ill is brought all the way to infinity, so 1/R ill drops out, and the object distance is 1/.009, or 111.111… An exercise for the reader would be to think of how to tweak the holographic set up (reference, object distance, and replay distance) for the maximum possible magnification, kind of like a holographic magnifying glass! Another tricky transformation that this equation implies is the change in object size when the wavelength is changed. This was Gabor’s impetus for developing holography; to shoot the hologram with short wavelengths, like electron waves or X-rays, and then replay it in the optical domain for an extreme magnification, namely on the order of the ratio of the wavelengths. Replaying a hologram shot with 6 nm X-Rays with a 589 nm sodium vapor light (this is pre-laser era!) would yield approximately a 100X magnification! Reading the early papers of Gabor and Rogers they did attempt to experimentally verify this by exposing holograms with the blue line of a mercury vapor lamp and replaying it with its green line! Theoretically satisfying, the big practical stumbling block was being able to supply a point source of the really short lambdas! ==Longitudinal Magnification== [[Image:LongMagEq.gif]] ==Vertical Focus== [[Image:VertFocusEq.gif]] ==Off Axis Lateral Magnification== [[Image:LatMagOffEq.gif]] 8a1c53ac6853a0ae9fac0303639bcc2dc6c5fc58 0 281 410 409 2013-05-12T02:52:03Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==What is a hologram?== Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ==How little money/bother do I need to make one?== You can make your first hologram with about 2 hours of set up and about $100. ==What is the cheapest way to make a hologram?== [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ==Are the chemicals dangerous?== While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ==What sort of time commitment is there for making a hologram?'''== You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ==When can I have the lights 'on' during the procedure of making a hologram?== Once the emulsion has become insensitive to to light. For Silver Halide holograms this is after the hologram is bleached. For Dichromated Gelatin holograms this is after the fixing and rinsing steps. ==What are the different kinds of holograms?== [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ==What is the single most important factor when making a hologram?== '''Stability!''' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ==How Does a LASER work?== For a simple introduction to lasers read [[How Do LASERs work?]]. ==Can I use a cheap red laser pointer to make holograms?== Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ==Can I use a Green Laser Pointer to make holograms?== So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ==Where are the Reference and Object beams in a Single Beam Reflection Hologram?== Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ==Some uses for [[Everyday Items]] in holography== Click here for [[Everyday Items]] that can save you money in holography! ==What is a [[Scratch-O-Gram]]?== A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and ficusing it from a curved scratch to a point. ==What Books are Available for Holography?== See the [[Books]] section. ac4f0c8a6cc507fe2af34cfee09b4bc95831c9f0 0 282 412 411 2013-05-12T02:52:03Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==How a Laser Works== Mirrored from Lawerence Livermore Labs [[Image:HowLaser1.gif]] ===Background=== The word "laser" stands for "light amplification by stimulated emission of radiation." Lasers are possible because of the way light interacts with electrons. Electrons exist at specific energy levels or states characteristic of that particular atom or molecule. The energy levels can be imagined as rings or orbits around a nucleus. Electrons in outer rings are at higher energy levels than those in inner rings. Electrons can be bumped up to higher energy levels by the injection of energy-for example, by a flash of light. When an electron drops from an outer to an inner level, "excess" energy is given off as light. The wavelength or color of the emitted light is precisely related to the amount of energy released. Depending on the particular lasing material being used, specific wavelengths of light are absorbed (to energize or excite the electrons) and specific wavelengths are emitted (when the electrons fall back to their initial level). The ruby laser was the first laser invented in 1960. Ruby is an aluminum oxide crystal in which some of the aluminum atoms have been replaced with chromium atoms. Chromium gives ruby its characteristic red color and is responsible for the lasing behavior of the crystal. Chromium atoms absorb green and blue light and emit or reflect only red light. For a ruby laser, a crystal of ruby is formed into a cylinder. A fully reflecting mirror is placed on one end and a partially reflecting mirror on the other. A high-intensity lamp is spiraled around the ruby cylinder to provide a flash of white light that triggers the laser action. The green and blue wavelengths in the flash excite electrons in the chromium atoms to a higher energy level. Upon returning to their normal state, the electrons emit their characteristic ruby-red light. The mirrors reflect some of this light back and forth inside the ruby crystal, stimulating other excited chromium atoms to produce more red light, until the light pulse builds up to high power and drains the energy stored in the crystal. The laser flash that escapes through the partially reflecting mirror lasts for only about 300 millionths of a second-but very intense. Early lasers could produce peak powers of some ten thousand watts. Modern lasers can produce pulses that are billions of times more powerful. Another characteristic of laser light is that it is coherent. That is, the emitted light waves are in phase with one another and are so nearly parallel that they can travel for long distances without spreading. (In contrast, incoherent light from a light bulb diffuses in all directions.) Coherence means that laser light can be focused with great precision. Many different materials can be used as lasers. Some, like the ruby laser, emit short pulses of laser light. Others, like helium-neon gas lasers or liquid dye lasers emit a continuous beam of light. Our ICF lasers, like the ruby laser, are solid-state, pulsed lasers. ===How the First Ruby Laser Works=== [[Image:HowLaser2.gif]] In contrast to an ordinary light source, a laser produces a narrow beam of very bright light. Laser light is "coherent," which means that all of a laser's light rays have the same wavelength and are in sync. [[Image:HowLaser3.gif]] 1. High-voltage electricity causes the quartz flash tube to emit an intense burst of light, exciting some of the atoms in the ruby crystal to higher energy levels. [[Image:HowLaser4.gif]] 2. At a specific energy level, some atoms emit particles of light called photons. At first the photons are emitted in all directions. Photons from one atom stimulate emission of photons from other atoms and the light intensity is rapidly amplified. [[Image:HowLaser5.gif]] 3. Mirrors at each end reflect the photons back and forth, continuing this process of stimulated emission and amplification. [[Image:HowLaser6.gif]] 4. The photons leave through the partially silvered mirror at one end. This is laser light. There are many types of lasers, including solid-state, gas, semiconductor, or liquid. The ruby laser is a solid-state laser. Solid-state lasers provide the highest output power of all laser types. The National Ignition Facility laser will also be a solid-state laser, but will use a special glass (rather than crystals of ruby) to amplify the initial laser pulses to very high energy levels. The NIF laser will be the most powerful laser in the world. 1377da2c3122bb3819bb9a7e4dd44613c070ff78 0 283 414 413 2013-05-12T02:52:04Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Impressionism''' - art movement in which painters broke away from the techniques of continuous brushstrokes and clearly expressed detail. They were largely concerned with the effects of light and color. *'''Infectious development''' - development action which occurs in processing "lith" materials. The oxidation of hydroquinone produces new and highly active reducing agents, semiquinones, in the presence of a low quantity of sodium sulfite. This results in a very high contrast image. *'''Intensification''' - chemical method of increasing the density of the photographic image. It is only suitable for treating negative materials and works better on negatives that have been underdeveloped rather than underexposed. *'''Intermittency effect''' - states that, a number of short, separate exposures will not produce the same photographic result when combined as a single exposure of equivalent total duration. *'''Intersection of thirds''' - compositional technique whereby the image area is divided horizontally and vertically into equal thirds by means of four imaginary lines. The main subject is considered strongly placed it it is positioned at the intersection of any two of these lines. *'''Inverse square law''' - states that, when the light source is a point, illumination on a surface is inversely proportional to the square of the distance of the light source. *'''Iodine''' - chemical used in reducers and bleachers. *'''Isoionic Point''' - The pH where the concentration of the dipolar ion is at a maximum *'''Ivorytype''' - obsolete printing process designed to give the impression of a painting on ivory. A hand colored print was impregnated with wax and squeegeed face down on hot glass. The paper base was then back by ivory tinted paper. ce411fc9568baa73f7175267ab508af4b5962e52 0 284 416 415 2013-05-12T02:52:04Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[http://www.hololab.com/ Ikuo's Web Site]] 200725896d40d33e07643c6a48fa314af6f00dc5 6 285 418 417 2013-05-12T02:52:04Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 107 420 107 2013-05-12T02:52:04Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 95 422 95 2013-05-12T02:52:04Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 96 424 96 2013-05-12T02:52:04Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 97 426 97 2013-05-12T02:52:05Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext 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519c08da88276b2f47bc6fb30637d415fd0d804e 6 146 556 146 2013-05-12T02:52:15Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 304 558 557 2013-05-12T02:52:15Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 305 560 559 2013-05-12T02:52:15Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 148 562 148 2013-05-12T02:52:15Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 150 564 150 2013-05-12T02:52:15Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 147 566 147 2013-05-12T02:52:15Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 306 568 567 2013-05-12T02:52:16Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 149 570 149 2013-05-12T02:52:16Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 151 572 151 2013-05-12T02:52:16Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 307 574 573 2013-05-12T02:52:16Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 308 576 575 2013-05-12T02:52:16Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 309 578 577 2013-05-12T02:52:17Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 310 580 579 2013-05-12T02:52:17Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 311 582 581 2013-05-12T02:52:17Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 312 584 583 2013-05-12T02:52:17Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 313 586 585 2013-05-12T02:52:18Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 32 588 32 2013-05-12T02:52:18Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 314 590 589 2013-05-12T02:52:18Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 315 592 591 2013-05-12T02:52:18Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 152 594 152 2013-05-12T02:52:18Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 316 596 595 2013-05-12T02:52:18Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 317 598 597 2013-05-12T02:52:19Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 318 600 599 2013-05-12T02:52:19Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 319 602 601 2013-05-12T02:52:19Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 320 604 603 2013-05-12T02:52:19Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 321 606 605 2013-05-12T02:52:20Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 322 608 607 2013-05-12T02:52:20Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 323 610 609 2013-05-12T02:52:20Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 324 612 611 2013-05-12T02:52:20Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 325 614 613 2013-05-12T02:52:21Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 326 616 615 2013-05-12T02:52:21Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 327 618 617 2013-05-12T02:52:21Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 328 620 619 2013-05-12T02:52:21Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 329 622 621 2013-05-12T02:52:22Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 330 624 623 2013-05-12T02:52:22Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 331 626 625 2013-05-12T02:52:22Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 332 628 627 2013-05-12T02:52:22Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 154 630 154 2013-05-12T02:52:22Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 25 632 25 2013-05-12T02:52:22Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 26 634 26 2013-05-12T02:52:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 27 636 27 2013-05-12T02:52:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 28 638 28 2013-05-12T02:52:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 29 640 29 2013-05-12T02:52:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 30 642 30 2013-05-12T02:52:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 31 644 31 2013-05-12T02:52:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 153 646 153 2013-05-12T02:52:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 333 648 647 2013-05-12T02:52:23Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 334 650 649 2013-05-12T02:52:24Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 335 652 651 2013-05-12T02:52:24Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 336 654 653 2013-05-12T02:52:25Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 337 656 655 2013-05-12T02:52:25Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 338 658 657 2013-05-12T02:52:25Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 339 660 659 2013-05-12T02:52:25Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 33 662 33 2013-05-12T02:52:25Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 34 664 34 2013-05-12T02:52:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 35 666 35 2013-05-12T02:52:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 36 668 36 2013-05-12T02:52:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 37 670 37 2013-05-12T02:52:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 38 672 38 2013-05-12T02:52:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 39 674 39 2013-05-12T02:52:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 41 676 41 2013-05-12T02:52:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 40 678 40 2013-05-12T02:52:26Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 42 680 42 2013-05-12T02:52:27Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 340 682 681 2013-05-12T02:52:27Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 341 684 683 2013-05-12T02:52:27Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 342 686 685 2013-05-12T02:52:27Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 43 688 43 2013-05-12T02:52:27Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 44 690 44 2013-05-12T02:52:27Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 343 692 691 2013-05-12T02:52:28Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki A simple constant current source for a laser diode. 90f9ad444139d094484f511968e082b58ed7cad5 6 344 694 693 2013-05-12T02:52:28Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Power Source eccc3205e121f540e66387a9aa3e240cff28df30 6 45 696 45 2013-05-12T02:52:28Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 53 698 53 2013-05-12T02:52:28Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 46 700 46 2013-05-12T02:52:28Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 54 702 54 2013-05-12T02:52:28Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 55 704 55 2013-05-12T02:52:28Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 56 706 56 2013-05-12T02:52:29Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 47 708 47 2013-05-12T02:52:29Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 48 710 48 2013-05-12T02:52:29Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 49 712 49 2013-05-12T02:52:29Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 50 714 50 2013-05-12T02:52:29Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 51 716 51 2013-05-12T02:52:29Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 52 718 52 2013-05-12T02:52:29Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 345 720 719 2013-05-12T02:52:30Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 346 722 721 2013-05-12T02:52:30Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 347 724 723 2013-05-12T02:52:30Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 348 726 725 2013-05-12T02:52:30Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 57 728 57 2013-05-12T02:52:30Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 58 730 58 2013-05-12T02:52:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 59 732 59 2013-05-12T02:52:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 60 734 60 2013-05-12T02:52:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 61 736 61 2013-05-12T02:52:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 70 738 70 2013-05-12T02:52:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 62 740 62 2013-05-12T02:52:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 63 742 63 2013-05-12T02:52:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 64 744 64 2013-05-12T02:52:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 65 746 65 2013-05-12T02:52:31Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 66 748 66 2013-05-12T02:52:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 67 750 67 2013-05-12T02:52:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 68 752 68 2013-05-12T02:52:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 69 754 69 2013-05-12T02:52:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 71 756 71 2013-05-12T02:52:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 72 758 72 2013-05-12T02:52:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 73 760 73 2013-05-12T02:52:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 74 762 74 2013-05-12T02:52:32Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 349 764 763 2013-05-12T02:52:33Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 75 766 75 2013-05-12T02:52:33Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 350 768 767 2013-05-12T02:52:33Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 76 770 76 2013-05-12T02:52:33Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 77 772 77 2013-05-12T02:52:33Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 78 774 78 2013-05-12T02:52:33Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 79 776 79 2013-05-12T02:52:33Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 80 778 80 2013-05-12T02:52:34Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 81 780 81 2013-05-12T02:52:34Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 82 782 82 2013-05-12T02:52:34Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 83 784 83 2013-05-12T02:52:34Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 84 786 84 2013-05-12T02:52:34Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 351 788 787 2013-05-12T02:52:34Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 352 790 789 2013-05-12T02:52:35Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 89 792 89 2013-05-12T02:52:35Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 85 794 85 2013-05-12T02:52:35Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 86 796 86 2013-05-12T02:52:35Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 87 798 87 2013-05-12T02:52:35Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 353 800 799 2013-05-12T02:52:36Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 354 802 801 2013-05-12T02:52:36Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 355 804 803 2013-05-12T02:52:36Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 88 806 88 2013-05-12T02:52:36Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 356 808 807 2013-05-12T02:52:36Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 357 810 809 2013-05-12T02:52:37Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 90 812 90 2013-05-12T02:52:37Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki 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Updated image of the SPER light meter baab0273dcdad4bfa1d0359f33d6eb62a059403d 6 8 840 8 2013-05-12T02:52:39Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 363 842 841 2013-05-12T02:52:39Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 364 844 843 2013-05-12T02:52:39Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 365 846 845 2013-05-12T02:52:40Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 366 848 847 2013-05-12T02:52:40Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 367 850 849 2013-05-12T02:52:40Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 368 852 851 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MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 371 866 865 2013-05-12T02:52:42Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki A temperature controlled diode laser 87f8a37fae3224989a6ca24576fd5824790059e4 6 372 868 867 2013-05-12T02:52:42Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki A temperature stabilized laser diode a3e9858c28a332e1188c245870b8d6174cecfb9a 6 12 870 12 2013-05-12T02:52:42Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 11 872 11 2013-05-12T02:52:42Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 373 874 873 2013-05-12T02:52:42Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki How it looks. :) aaec8421cdb668a79950c02d258c6c1e5a32b1c1 6 374 876 875 2013-05-12T02:52:42Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 375 878 877 2013-05-12T02:52:43Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 376 880 879 2013-05-12T02:52:43Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Top view 9d597493304aed540ed1f806581a50f570082497 6 377 882 881 2013-05-12T02:52:43Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Top View e800176ba71bf1fe8e9abff8def5e052dfc9da34 6 13 884 13 2013-05-12T02:52:43Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 14 886 14 2013-05-12T02:52:43Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 15 888 15 2013-05-12T02:52:44Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 16 890 16 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revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 389 918 917 2013-05-12T02:52:47Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 390 920 919 2013-05-12T02:52:47Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 391 922 921 2013-05-12T02:52:48Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 19 924 19 2013-05-12T02:52:48Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 20 926 20 2013-05-12T02:52:48Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 23 932 23 2013-05-12T02:52:48Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 24 934 24 2013-05-12T02:52:48Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 392 936 935 2013-05-12T02:52:49Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==Mounting Holographic Film== When choosing a index matching fluid it is important to have it be safe to handle, it can not evaporate to quickly, it must clean up without destroying the un-developed gelatin and it's [[Refractive Index]] should be glose to in-between glass and gelatin. That may be true for a great many “special applications” but probably not for the recording of display holograms. In the 80s, when we started working with Agfa's 8E75 material (back then coated on Melinex polyester film), we routinely used plain tap water for “index matching”. Though the refractive index of water hugely differs from that of Melinex (that's to say from 1.33 to roughly 1.64 or so), the mismatch did not show up in the final holographic image. Actually, it could only be detected if the film was examined in a transmission mode. It turns out the main issue here is keeping the film stable on a glass plate during exposure. Whereas polyester was very forgiving in that respect, handling nowadays' triacetate has become a lot trickier. If you are using film instead of glass plates then a method to hold the film stable is very important. The usual method with the AGFA materials is to use an index matching fluid to hold the film emulsion side out to a oversize glass plate. The simplest index matching fluid to use is liquid paraffin. This is sold as lamp oil. Make sure to get the oderless and smokeless variety as it is much more pure. The index of refraction is a little low but it works fairly well. Make sure to wash it off before you develop it. Use a drop or two of dish soap in 1/2 gallon of distilled water as a rinse before development. I would like to add that other liquids might be equally worth a try. E.g. white spirit and the like: paint thinner, paint cleaners etc. (provided they are low toxic of course). As I have just discovered there is also an ''odourless white spirit artist's quality'', made by Talens. Cedar oil might be another option. Compared to paraffin those liquids have the advantage of being removed quickly from the film – simply by warm air. It is very important to use the right amount of index matching fluid. Use an eye dropper to measure the fluid onto the plate. A syringe would be useful for larger plates. If you have air bubbles they will show up as blank portions of the holograms because the film will move. If you have too much then you have much to clean up before you can use the sandwich. If you get index matching fluid on the wrong side of the plate it is very difficult to clean it off under the safelight. Before using the sandwich check it in both transmitted safelight and reflected safelight to check for bubbles or smears. The AGFA materials and now the Fuji materials have a gelatin coating on both sides! This makes using the single plate method very easy. If you are using the Slavich materials they will often curl up on you. This has been attributed to the thinner triacitate base stock but it is likely it is the lack of a second gelatin coating. For the Slavich materials sandwich the film in between two glass plates. This can be done with index matching fluid. Slight correction regarding Agfa. Yes, they did a couple of film batches with gelatin coated on both sides. But that has been rather an exception. Speculating about the reason for the superiority of Agfa's materials (with respect to ease of handling prior to exposure only!), one might consider the particular triacetate film produced by Bayer or, a special subbing layer, used by Agfa or, the whole thing relates to the topcoat. Personally, I do not think it was just a matter of film thickness. If memory serves, Ilford materials (SP-673, HOTEC) used to have a similar film thickness. And yet, index matching those films on a glass plate became pretty challenging. Slavich (PFG-01 and PFG-03), Red Star, Ultimate and Filmotec all were similarly difficult to handle. Beside making index matched glass-film-glass sandwiches, glass-film-plastic sheet sandwiches seemed to work reasonably well. E.g. we would pour some index matching liquid on the middle of the glass plate and then apply the holographic film (emulsions side towards the liquid) to the glass. On top of the holographic film (base side) by means of some additional index matching liquid a plastic sheet (PMMA, PC etc. plate or some OHP film etc.) was applied. In those cases, adding a surfactant (Triton-100) to the index matching liquid used make life easier. ==Dry Film Mounting== Frank DeFreitas has an interesting mounting method. Here is some information from a post he made to his forum (now retired forum) at [http://www.holoworld.com holoworld]. It also has some very good information about finding the Brewster's angle. Frank DeFreitas - Mon, May 28, 01 10:51:49 PM When running test after test working with diodes in the now "early" days, I had to come up with a way of not going broke using glass plates -- while also keeping the quality of the holograms intact and consistent -- so that any problems would be from the laser test itself, and not the set-up. Of course, this meant working with film (AGFA-8E75HD at the time). With both time constraints and the shear number of test shots, I quickly became aware that wet-mounting was just too much to do each time. So here's what I did: Since the very nature of holography requires that glass plates be manufactured to exacting specs in regards to flatness, I took two old plates and placed them in a standard Clorox bleach solution. Within several minutes, the emulsion turns to a white paste and can be rinsed off with water -- leaving just the glass substrate. This took care of the problem with commercial glass and it's inconsistent "flatness" for sandwiching. NOTE: Since this IS a chemical reaction taking place, when removing the emulsion with bleach, use a fume-hood or do this outdoors. Once rinsed, clean the glass off with any standard window cleaner and take care to store them so they do not become scratched. Any scratch will show up in the final hologram -- and, if it is deep enough, actually create a shadow -- due to the angled surface of the physical scratch itself. Then, just take your film and sandwich it between the two pieces of glass. My method was to "squeeze" the glass together with a twisting motion while applying downward pressure. If done properly, you will create your own vacuum and the entire sandwich will stay together as one unit. When you REALLY get the hang of it, you'll find it hard to get it apart! Now, for the set-up: You will need a polarized laser and make sure that the polarization is properly oriented to your plateholder. You will also need to bring your reference beam (or single beam) in at "exactly" brewsters angle. One way to determine this is to set up your plateholder at brewsters and place a single piece of glass in it. Hit the glass with your spread beam. The glass is going to reflect some of the light hitting it, so place a white card in this reflected light path (in order to view it). If you rotate your laser head, you will notice that this reflected light becomes brighter and dimmer. Find the spot within the rotation where the reflected light is at it's dimmest on your white card, and you've got it. There should be two spots for this with every 360-degree of rotation. With my HeNe, it is at the 3:00 and 9:00 position(s) for side-reference (parallel to table). With the diode, it is at 12:00 and 6:00. With a HeNe, you'll always have a "little" bit of light reflected. With a properly-running diode, the reflection will go completely out on the card (100% -- or VERY close to 100% -- transmission through the glass). For side referencing, also make sure that your plateholder is not angled toward or away from the incoming laser light, too. It should be straight up and down in relation to the reference beam. This also means making sure that your incoming laser light stays parallel to the surface of the table . . . and is not directed upwards or downwards in any way toward the plateholder during it's travel. If you're using an overhead reference, then it should not be angled in any way from either SIDE. In other words, the ONLY "angle" present should be the reference angle -- no matter what table geometry or set-up you're using. Place your sandwich into the plateholder and give it time to "settle". It will take much longer with film than with a glass plate. I usually use this time to get chemistry ready, or go upstairs and have a cup of tea and relax, etc. Do your exposure as you normally would. If you have everything set-up properly as stated above, you will have a film hologram that is every bit as clear, bright and clean as one on glass plates -- without the cost of plates and without any type of index matching fluid or the associated mess and/or extra time. In closing, I have heard that the .mil thickness of the new film out there is less than it was previously with AGFA . . . so this may require a few "tweaks" here-and-there with settling time, etc. Regards, Frank ==Links== Micheal Harrison has a great article [http://www.dragonseye.com/blog/archives/15-Laminating-film-to-glass.html here!] 29cb3150832280aef117527dfda3e830248b42a3 0 393 938 937 2013-05-12T02:52:49Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ===The Michelson Interferometer=== http://www.dragonseye.com/interferometer.jpg This is one of the most useful tools in a holographer's laboratory. Placed on the holographic table and observed carefully, it can answer many questions - * how long does it take for the table to settle after components are moved? (this could be minutes to hours to a day or more!) * does the table ever completely settle? * what outside factors influence the stability of the set up? (like hearing a car going by and seeing if the fringes move) * what times of day are the most stable? * are the movements due to air movement, vibrations, temperature etc. ? * how long does it take the table to settle after a plate is loaded? and a variety of other useful vibration feedback. If the Michelson is rigidly fixed on an optical rail and allowed to equalize then the interferometer can be used to study properties of the laser such as mode hop behavior, drift and coherence length. ====How It Works==== The Michelson Interferometer uses a beam splitter to split a laser beam into two beams. Each beam takes a different path towards its own mirror which reflects it back into the beamsplitter which now acts to combine the beams so that they overlap. The overlapped beams are fed through a lens and expanded onto a wall or white card. The beams interfere to form fringes which can be seen and studied. The beams in the diagram are slightly offset so that the laser light isn't reflected back into the laser cavity. This reflection back into the laser can cause gas lasers to fluctuate in power and cause fringe movement and even ruin diode lasers. ====Diagnosing Fringe Behavior ==== *Fringes drift slowly back and forth, either continuously or sporadically - This is most likely due to air currents. Create a breeze and see if it affects the drift. *Fringes move slowly and continually in one direction - This is drift and most likely an optic is drooping or the table is sagging in one spot (this is most often seen on sand tables). *Fringes jitter rapidly - This is most likely caused by vibrations coming through the table legs or a fan or other electrical component on the table is vibrating. *Fringes stay stable then jump - This is called a mode hop. It is common when lasers are changing temperature. Allow your laser to warm up before use. If you aren't using a diode laser this can also be caused by air pressure changes. Make sure the AC is turned off and doors in your building aren't being opened and closed while testing with the interferometer or making an exposure. Inserting a plate into the plateholder - the time it takes for the fringes to stop moving is the minimum settling time needed after you load a plate for table movement to stop. [[Equipment#Longitudinal_Modes_and_Coherence_Length|Coherence Length]] - start with both legs of the interferometer set to exactly the same length (to within a millimeter if your coherence length is unknown). When you get all your mirrors aligned properly, you should see fringes. If and when you do, they should be contrasty, not washed out. If not, ask the holography forum for help. After the fringes stabilize, increase the length of one of the legs by a small amount. If fringes remain and are still contrasty your laser is still coherent to the length of the difference in path lengths. Continue to increase the length of the same leg until the fringes are not contrasty or disappear entirely. At this point you have exceeded your coherence length. To find the exact length start to go back from this length to the laser known good length in small increments. ====Tests==== Once the fringes are stable, do a variety of tests. Tap the table slightly and see how long it takes for the fringes to stop moving. Tap the floor with your foot and see how long it takes for the fringes to stop moving. Have someone tap the floor with their foot at different locations remote from the table, i.e. next room, upstairs, downstairs, further away etc. while you are viewing the fringes. Watch the fringes at different times of day - at night when streets are quiet, daytime when streets are busy etc. An excellent way to evaluate your table is to set up a camcorder aimed at the fringes and set a walkie-talkie next to it. Now move around your house/building and walk around, open and close doors, start machinery (if in a home, start your dishwasher etc) and generally cause vibrations while talking into a second walkie-talkie. You can then review the tape and see exactly what, if anything affects your ability to make a hologram in your lab. This tape also serves as a record of table behavior that can be used at a later date to compare current and past behavior. ===References=== Great references for using holograms as measuring tools: Schumann, W. and Dubas, M., Holographic Interferometry, Springer, 1979. Schumann, W., Zürcher, J. P., and Cuche, D., Holography and Deformation Analysis, Springer, 1985. 8d78817779f3b350c9b11dd2d1c90f977058eb2e 0 394 940 939 2013-05-12T02:52:49Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Joule''' - unit used to quantify the light output of electronic flash. A joule is equal to one watt second of 40 lumen-seconds. The measure is used to compare flash units in terms of power output. f9aead7abea7dec4702846f11147816eade568f6 0 395 942 941 2013-05-12T02:52:49Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:JBlyth.jpg]] a129eecfa2418870c4dc76082d5783d2808450ed 0 396 944 943 2013-05-12T02:52:50Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki '''A simple spatial filter design''' by John Klayer A few people asked to see my design, so here it is. It was published in the L.A.S.E.R. News Vol. X #4 Winter 1990-1991. It is very easy to use and not too difficult to build. [[Image:JKSpatialFilter1.jpg]] '''Parts list:''' '''A Carriage:''' 1/4 by 1-3/4 by 2-1/2 inch plexiglas. A 1-1/4 inch hole is centered 7/8 inch from the top. The top and one side are drilled and tapped to receive D1 and D2. A slot is filed at 45 degrees to receive F. (See the drawing below for an alternate method.) A hole is centered, drilled and tapped 3/8 inch from the bottom to receive E. Two holes 3/8 inch from the bottom and 1/4 inch from each side are drilled thru the carriage and the base h to receive I1 and I2 - use a #6 drill. (These holes need to be drilled thru the carriage and base in one operation.) Around the 1-1/4 inch hole three holes are drilled and tapped 120 degrees apart for the 2-56 screws that secure the fender washer C. '''B Magnet:''' A 1-1/8 inch ring magnet available from Radio Shack. '''C Plate:''' a 1-5/8 by 5/16 inch fender washer with three holes drilled 120 degrees apart for the 2-56 by 1/4 screws that secure it to the carriage A. '''D1, D2 Fine Positioning Screws:''' 0-80 by 1/2 machine screw, end rounded and fashioned into a thumbscrew by soldering onto the head the knurled disk part cut from a 10-32 knurled nut. The 10-32 knurled nut is cut by putting it on a 10-32 screw and turning it with a drill while applying a hacksaw blade. The soldering task can be simplified by using a wooden fixture to align and hold the knurled disk and the 0-80 screw: Bore a flat bottom hole 1/2 inch diameter by 1/8 inch deep into a block of wood then continue concentrically with a 1/16 inch hole. (I've thought about replacing the 0-80 screws with 2-56 screws.) '''E Focusing Adjustment:''' Same as D1 and D2 but use a 3/4 inch screw. '''F Spring:''' Closed and ground ends, length from 3/8 to 5/8 inch, about 1/8 inch diameter. '''G Pinhole Holder and Coarse Adjuster:''' Any piece of ferrous metal shaped similar to the illustration. Glue the pinhole to the ring part. The ring and handle should be able to lay flat against the magnet - this is important, otherwise the ring would be drawn to the magnet center and there wouldn't be any coarse adjustment. The handle part should extend beyond the edge of the carriage. You may find an item like this at a hardware store called a "ring hanger". '''H Base:''' 3/4 by 1-1/2 by 1-3/4 inch block of wood. Two holes drilled thru it 3/8 inch from the bottom and 1/4 inch from each side. These holes must align perfectly with the two in the carriage,A. To assure alignment, start with a sheet of plexiglas and a piece of wood about 2 inches wider, attach the plexiglas firmly to the wood with two wood screws and drill thru both, the saw to the 1-3/4 inch width. Make a notch 3/4 inch wide and 1/8 inch deep in the front to receive K. Centered on the top, drill a 3/4 inch flat bottomed hole partially thru and continue concentrically with a 5/16 inch hole the rest of the way to hold L. '''I1,I2 Sliding Shabts:''' Three inch aluminum screw posts (manufactured by Charles Leonard, Inc.) available from office supply stores. The normal use is for binding books. These have two heads, one attached to the shaft and the other screws into the other end. Insert the posts thru the carriage and base so that the screw end is to the back. Epoxy the front 1/4 inch of the posts inside the carriage holes. '''J1,J2 Focusing Springs:''' Any spring that will fit over the shaft with a lenght of about 1-1/2 inch and not too stiff. '''K Lens Mount:''' 3/4 by 1/8 inch aluminum. 1-5/8 inch from the bottom drill a hole the diameter of the lens. Drill and countersink two holes 3/16 and 9/16 inch from the bottom for two wood screws to secure it to the base. '''L Fastener:''' 1/4-20 by 3/4 inch T-nut secured in the hole in H by three small wood screws. This is to provide a means of mounting the assembly on a post. '''Lens:''' You could use a simple lens. What I found works real well is a "Hastings Triplet" from Edmund Scientific. Forget the microscope objectives. ---- An alternate design for the carriage magnet spring: [[Image:JKSpatialFilter2.jpg]] Here I'm using a hole drilled at 45 degrees with a head of a small nail against the magnet, a small spring held in the hole by a short section of brass tube epoxied in the hole. I used clear plexiglas for the first few I built then I found some black plexiglas. Use the black if you can find it. If you never tried drilling a 1-1/4 inch hole in plexiglas before, you're in for a real treat. I'm sure there are plenty other materials you can try besides plexiglas and wood. These materials worked for me. Good luck. [[Image:JKSpatialFilter3.jpg]][[Image:JKSpatialFilter4.jpg]] a5b093683c0ce3dbf5a285204c93642a182af9f0 0 397 946 945 2013-05-12T02:52:50Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki Sorry, I had more of a holography history for me then a biography. I have an AA degree from a local Community College with an emphasis in Computer Science. I furthered my education at University of Maryland with Physics, Math and Computer Classes. I am a Microsoft Certified Systems Engineer and presently design Wide Area Networks. I have worked at North East Holographics and responsibilities included: Design, configure and produce H1 multi-channel rainbow master holograms for replay with a HeCd laser using a large frame Argon Ion laser. Design, configure and produce H2 rainbow copy holograms in Photoresist utilizing a fringe locker to help with stability during the long exposure times and using a HeCd laser. Fabricate Photoresist emulsions on glass plates. Implemented quality control of Photoresist plates. Silverized the Photoresist plates with an atomizing spray system. Built, maintained and controlled variables for producing different types of Nickel Shims made from the Silverized Photoresist plates. Built, maintained and operated a complete wide format Embossing Printer used to hot stamp nickel shim hologram in foil backed plastics. I have also been involved with amateur holography since 1982 working with Silver Halide. Currently and for the past 3 years I have been concentrating my efforts in working with Fabrication and production of Dichromated Gelatin holograms implementing a variety of techniques formulas and geometries. I have moved from the basement to a dedicated lab. f03f3c53cb3b477bcc67f54174be4a09264d507c 0 398 948 947 2013-05-12T02:52:50Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:Jross.jpg]] JONATHAN ROSS [http://www.jrholocollection.com WebSite] CURRICULUM VITAE BORN 1953 London EDUCATED Bryanston School, Dorset 1970 - 71 Studied Art History in Venice and London 1972 - 77 Worked as assistant in Film Production and Theatre Management 1978 - 79 Founded and managed The Hologram Place - The first European gallery devoted to holography 1978 - 90 Founded and managed SEE 3 (HOLOGRAMS) LTD. - a production company for the manufacture of display holograms 1992 Organised “Four British Holographers” exhibition at Smith’s Gallery Covent Garden 1993 Organised “Landscapes & Metamorphoses” exhibition at Smith’s Gallery 1994 Organised “3x8+1” a selection of holograms from personal collection at Milton Gallery, St.Paul’s School, London 1995 Contributed selection of holograms to “Holograms from around the World” James Dun’s House (Aberdeen Art Gallery) Guest curator of “The Art of Holography” at the National Museum of Photography, Film & Television, Bradford 1996 Co-curator of “Raum in Sicht - Magie in 3-D”, Technorama Switzerland. Special Consultant to Art in Holography2 Symposium, Nottingham University Exhibited selection from collection and gave paper on collecting holograms. 1997 Exhibited selection from collection at The Royal Photographic Society, Bath. 1998 Founded Gallery 286 in Earl’s Court Road, London and has curated an ongoing programme of exhibitions featuring holographers, photographers, painters and sculptors. Over 50 exhibitions to date, including one-person shows by John Kaufman, Andrew Pepper, Margaret Benyon, Matthew Schreiber, Jon Mitton and Pearl John 1999 Advisor to the Shearwater Foundation Holography Award Programme 2000 A special Exhibition of work selected from the collection at The Butler Institute of American Art, Youngstown, Ohio, USA The Royal Photographic Society Holography Group Summer Exhibition 2000. A selection of work from the Jonathan Ross Collection. 2004 Received The Royal Photographic Society Saxby Medal for contributions to 3-D Image-making 1988 - 93 Consultant Editor, Art Line International Art News 1983 - Hon.Treasurer, Royal Photographic Society Holography Group During his long association with holography, Jonathan Ross has assembled one of the world's most extensive collections of holograms, details of which can be found at http://www.jrholocollection.com c493b47d5163d6f4898344f036ba3f16f3772b6b 0 399 950 949 2013-05-12T02:52:50Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 400 952 951 2013-05-12T02:52:51Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:JUpatnieks.jpg]] Director of Applied Optics Ann Arbor, Michagan Professor, Electrical and Computer Engineering Department University of Michigan Mechanical Engineering and Applied Mechanics Department University of Michigan Born: May 7, 1936, Riga, Latvia ---- ==List of Patents== *3,506,327 Wavefront Reconstruction Using a Coherent Reference Beam, 1970 *3,532,407 Spatial Frequency Reduction in Holography, 1970 *3,539,241 Method of Imaging Transparent Objects with Coherent Light, 1970 *3,545,835 Two-Beam Holography with Reduced Source Coherence Requirements, 1970 *3,548,643 Holographic Vibration Analysis Method and Apparatus, 1970 *3,580,655 Wavefront Reconstruction", 1971 *3,637,313 Method of Imaging Transparent Objects with Coherent Light, 1972 *3,677,617 Technique of Holographic Data Reduction Utilizing an Additional Diffusing Structure During Reconstruction, 1972 *3,748,048 Method of Detecting Changes in Specular Surface, 1973 *3,838,903 Wavefront Reconstruction, 1974 *3,894,787 Holograms, 1975 *4,012,150 Holographic Light Line Sight, 1977 *4,057,317 Hologram Projector, 1977 *4,223,975 Aberration Correction of Magnified Holographic Images, 1980 *4,277,137 Coherent Optical Correlator, 1981 *4,643,515 Method and Apparatus for Recording and Displaying Edge- Illuminated Holograms, 1987 *4,711,512 Compact Head-Up Display, 1987 *5,151,800 Compact Hologram Displays and Methods of Making Compact Hologram, 1992 *5,483,362 Compact Holographic Sight, 1996 6d18e713af1529cd397829690649fa163d236a5a 0 401 954 953 2013-05-12T02:52:51Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Kallitype''' - obsolete printing process, resembling the platinum process. The image is formed in metallic silver rather than expensive platinum. *'''Kerr cell''' - high speed shutter without moving parts, using two crossed polarizing filters at either end of a cylinder filled with nitrobenzine. *'''Key light''' - studio light used to control the tonal level of the main area of the subject. *'''Knifing''' - method of removing marks and other blemishes from the surface of a print by gentle scraping with the tip of a sharp knife. *'''Kostinsky effect''' - development effect in which dense image points are inclined to move apart, relative to each other, and light image points to move together, relative to each other. This occurs because developer is not being equally distributed over the image point and is rapidly exhausted when to heavily exposed image points are close together. *'''Kromskop''' - early viewing instrument invented by F.E. Ives, embodying a system of mirrors and color filters to synthesize a full color image. This enabled monochrome transparencies made from separation negatives to be rear-illuminated through blue, green and red filters, and then been seen combined in register as a single image. 73a8c06e88bb82b05dc9d587ce9abbbd3b016129 0 402 956 955 2013-05-12T02:52:51Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==KD*P KD2PO4== '''Properties''' *Phase Match Type II *Non-Linear Coefficient .37 10-12 m/V *Refractive Index 1.49 *Damage Threshold .5 GW/cm^2 *Absorption .005 cm^-1 *Phase Matching Angle 53.7 Deg. *Walk Off Angle 1.45 deg '''Tolerance Parameters ''' *Angular 2.2 mr-cm *Thermal 6.7 deg C-cm *Spectral .66 nm-cm '''Notes''' KD*P is very fragile and is quite hygroscopic. It is supplied in an index matched fluid filled cell to protect the crystal. It is available in very large sizes and is less expensive than KTP. 40711bfc645644d6528e1fbebac32332dd676279 0 403 958 957 2013-05-12T02:52:52Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki ==KTP - KTiOPO4== '''Parameters''' *Phase Match Type II *Non-Linear Coeffecient 3.18 x10^-12 m/V at 1064nm to 532nm *Refractive Index 1.74 *Absorption .010 cm^-1 *Transparent Range 350nm to 4000nm *Required Power Density 200MW/cm^2 *Damage Threshold 500MW/cm2 *Phase Matching Angle 24.3 deg *Walk-off Angle .26 Deg *Melting Point 1150 deg C *Lifetime at 80 Deg C and 150MW/cm^2 20 x 10^7 pulses '''Tolerance Parameters (FWHW)''' *Angular 25 mr-cm *Thermal 25 Deg C-cm *Spectral .56 nm-cm 4ccd52cfd1b296bf3955175ab0185696d22a71e7 0 404 960 959 2013-05-12T02:52:52Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki [[Image:KBazargan.jpg]] Optics has interested me ever since I was a small child. Everything from how a movie was projected in a cinema, to why shadows were sometimes sharp and sometimes not, constantly occupied my mind. This inquisitiveness finally led to a masters degree in Optics, at Imperial College, London. Here I developed an interest in holography, so I stayed on to complete a PhD in Display Holography. I have uploaded the thesis [http://www.focalimage.com/public/kaveh-PhD.pdf here]. The two areas I worked on most were natural color holography, and dispersion compensation. For colour holography I proposed using the three "prime" colors (as first identified by W A Thornton in 1971) for image recording. The work on dispersion compensation led to a compact hologram viewer which was patented, and is now marketed as the [http://www.apple.com/science/profiles/voxel/ "VoxBox"]. After 5 years of research in holography I was distracted by the fascinating emergence of "desktop publishing", and set up a graphics and typesetting [http://www.river-valley.com company] in 1988, which is now established and pays the bills. I am now raising my head again in holography and hope to continue where I left off. [http://www.holographer.org The Holographer] represents my re-entry into the field. 28734756aa7636407946e6d306646253d4cc12ec 0 405 962 961 2013-05-12T02:52:52Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki A knife is a broad word encompassing a large number of tools. The cheapest knife to buy and maintain is an x-acto knife. [[Image:XactoNo1.jpg]] The no. 1 knife handle with the no. 11 blade is the most common knife we associate with X-Acto but they make a broad product line for model makers. The blades are stainless and never get as sharp as a steel blade. [[Image:XactoX2000.jpg]] A more comfortable handle is the X-2000. X-Acto knife blades are cheap enough that sharpening is not required. The blades are simply replaced. [[Image:ViolinMakersKnives.jpg]] A better knife is a violin makers knife. You can sharpen the blade and trim back the handle for a lifetime. They are available in German steel and Japanese Steel. The German steel is more durable (chips less easily). The Japanese steel gets sharper and stays sharp longer but chips quite easily. ===Sharpening Knives=== Sharpening knives is a task of patience. You must completely sharpen one face to completion before moving on to a finer grit. You may stop at anytime the knife is sharp but what is described below will make a knife sharp enough to shave. [[Image:KniveAngles.jpg]] The angle you sharpen at is chosen based on what the knife will be used for. Use a blunt angle for rough work and a durable blade and use a sharp angle for delicate work. [[Image:KnifeSharpening.jpg]] *Rough out both sides in a single plane with a course stone. *Polish the faces with a fine stone. *Hone the knife on a leather strop with red compound (rouge). *Hone the knife on a 2nd leather strop with white compound. [[Image:KnifeSharpeningStages.jpg]] Tips: *Do not switch to fine grit until all chips have been removed. *Be careful to not round the edge. You need one plane from the shank of the knife to the edge. *Sharpen both sides evenly. Safety Tips: *Do not pull a knife towards your body or fingers. [[Image:KnifeSharpeningTips.jpg]] ===Links=== [[http://www.frets.com/FRETSPages/Luthier/Technique/ToolUse/KnifeTechnique/knifetech01.html Master Luthier Frank Ford on Knives.]] eb1ce34b412a47edb5796a31f60ae8807c389e3b 0 406 964 963 2013-05-12T02:52:52Z Jsfisher 1 1 revision: Base recovered wiki articles wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Lamp black''' - pure carbon pigment, made from soot deposited from burning oils. *'''Laser''' - an achronym for Light Amplification by the Stimulated Emission of Radiation. It is a device that emits a light beam that has special qualities. Most lasers are a pure color and travel in a beam with out spreading. *'''Lead acetate''' - crystalline, highly poisonous powder used in some toning and intensifying solutions. *'''Latensification''' - method of increasing relative film speed by fogging after exposure and before development. It can be achieved by chemical or light means. *'''Lenticular screen''' - lens system consisting of a screen containing a number of small lenses.There are two applications of lenticular systems. They are used in some exposure meters to gather light and to determine the angle of acceptance of light by the meter. A lenticular screen consisting of a number of lenses et into rows can be used at the camera stage to produce stereoscopic images by synthesizing binocular vision. *'''Light trap''' - system of entry to a darkroom which allows easy access, but prevents unwanted light from entering. *'''Linked Ring Brotherhood''' - group of pictorialist photographers who broke away from the Photographic Society of Great Britain. Existed between 1892-1910. *'''Lippmann process''' - early color process invented by Professor Gabriel Lippmann (1845-1921). Light first passed through an almost transparent emulsion layer and was then reflected back by a layer of mercury. The interference between reflected and incident light produced a latent image in the emulsion which could be given b&w processing, but when backed with a mirror appeared in color. *'''Local control''' - method of controlling the final quality of a print by increasing or decreasing the exposure given to localized areas of the print by selective masking. e2d51e9a6d472abb23276e065b71bdb1d1cd1413 0 408 967 966 2013-05-12T02:54:19Z Jsfisher 1 1 revision wikitext text/x-wiki ==LBO== 577d3295490630caace6d6451dd0b4d98a527036 0 409 969 968 2013-05-12T02:54:20Z Jsfisher 1 1 revision wikitext text/x-wiki From Hanz: A much better method was to use a washable childrens glue (made by pritt) to stick the film to the glass. For that purpose I used a laminator. I disconnected the heating element from the laminator. Here is the procedure: * Tape the film on one side to a piece of 2mm thick glass. * Deposit a stripe of the glue where the film and glass meet. * Very gently allow the film to hinge onto the glass. * Put the glass onto a piece of paper. The paper must me larger than the glass so that it comes out of the laminator first. * Gently rest another piece of paper on top of the glass. (The pieces of paper prevent glue from entering the laminator). * Run this sandwich through the laminator. * If the laminator struggles to run the glass through you can pull on the two paper sheets that first come out of the laminator. * Let the sandwich rest for a few minutes and then pull the paper from the top of the lass. Start pulling from the side where the Scotch tape holds the one side of the film to the glass. This method allows the film to be processed as if it were a glass plate. If you want to remove the film from the glass (when using the glue that I used), just warm it up with a hair drier. It will then just curl of the glass. Any remaining glue can be washed off with normal tap water. b77b3f40c1a254ee640fd2910a71a40509456c65 0 410 971 970 2013-05-12T02:54:20Z Jsfisher 1 1 revision wikitext text/x-wiki The word laser is an acronym for Light Amplification by the Stimulated Emission of Radiation. [[Image:Laser_Spectrum.png]] For a simple explaination about LASERs read [[How Do LASERs work?]] Information about [[Types of Lasers]] can be found here. ====Laser properties==== =====Color===== The color of a laser is related to the physics of the lasing medium. Holography grade lasers are made in almost every color of the rainbow from UV to IR. The most common colors (lines) used for holography are 650nm red ([[Types_of_Lasers#Diode_Lasers|laser diodes]]), 633nm ([[Types_of_Lasers#HeNe_Lasers|Helium-Neon Lasers]]), 532nm (frequency doubled Yag [[Types_of_Lasers#DPSS_Lasers|DPSS lasers]]) , 514nm and 488nm ([[Types_of_Lasers#Argon_Ion_Lasers|argon lasers]]). =====Power===== Power is the measurement of the energy contained in the beam. For continuous wave lasers (CW) is is measured in milliwatts (mw) or watts (W). The more power a laser has the shorter the exposure time will be, and consequently, the less stringent the constraints on table stability are. While it is possible to create holograms with laser powers of 1mW and less, 5mW or more is recommended in order to have conveniently short exposure times for usual film sizes. On the other hand, going much beyond this power level creates a severe danger for the eyes; in principle, one should always use as little power as necessary for a given application. Typical power levels of [[Types_of_Lasers#HeNe_Lasers|HeNe lasers]] are 1-20mW, of [[Types_of_Lasers#Diode_Lasers|diode lasers]]: 5-50mW, of [[Types_of_Lasers#DPSS_Lasers|DPSS lasers]]: 20-200mW, and of [[Types_of_Lasers#Argon_Ion_Lasers|argon lasers]] with etalon: 100-500mW. But, if the money is no object powers of over 1 watt can be obtained in Argon and DPSS lasers. The power for pulsed lasers is measured in Joules. Most holographic Pulsed laser systems fall into the .1 to 10 Joule range and are of a [[MOPA]] design and either Frequency Doubled ND:YAG/ND:Glass lasers or Ruby Lasers. =====Divergence===== Laser beams do not stay the same diameter as they travel. They expand and the rate of the expansion is measured in millirads. The divergence of a laser is of little importance to holography. However when blending lasers of different frequencies for color work it is important to match the divergences. =====Polarization===== While any [[polarization]] state will make a hologram a polarized laser will make the most efficient holograms. Lasers are usually classified as either non-polarized or a polarization ratio is specified like 100 to 1. When a laser is listed as non-polarized it means that there are no optics to set the polarization angle. This does not necessarily mean the beam is not polarized but often that the polarization of the beam rotates as time passes. In order to set the polarization of a laser there needs to be a polarizer in the cavity. The most common polarizer is an optic set at the [[Brewster's Angle]]. I can be one of the cavity mirrors or a window in the cavity. =====Transverse Modes===== [[Image:PolarizedModes.png]] This image shows the modes for polarized lasers. A laser for holography needs to be TEM00. This stands for Transverse Electric Mode. It is a measure of how even the laser beam is in cross-section. Using a laser with a higher order mode makes it impossible to get even illumination, and also the individual spatially distinct beam components may not be in phase with each other (ie, cannot interfere to form a hologram). A TEM00 beam has a [http://en.wikipedia.org/wiki/Gaussian_beam Gaussian] distribution. =====Longitudinal Modes and Coherence Length ===== Besides various [[Equipment#Transverse_Modes|Transverse Modes]], a laser can also emit various longitudinal modes which have just slightly different wavelengths. This is because the resonance condition can be satisfied by many different wavelengths. That is, assuming the laser resonator has length L, it allows all modes to be present whose wavelength lambda satisfies L= N lambda/2, where N is an integer. So if lambda is very small (like 600nm) and the condition is satisfied by some very large N, then it is also satisfied by a slightly different lambda and a slightly different N. The frequency difference of two adjacent modes is called mode spacing and given by delta_f = c/(2L). In practice, the laser material won't amplify any possible resonance mode, but only frequencies that lie within a certain gain window, so at most a few longitudinal modes will be able to lase. With special methods, like using an [[Equipment#Etalon|etalon]], one can achieve a clean single frequency operation. The presence of more than one longitudinal mode is a serious obstacle against recording holograms with significant depth. The reason is that when several modes with slightly different wavelengths are present, they will be out of phase after having traveled a certain distance D. The quantity D is customarily called <b>coherence length</b>. It leads to a blurring of the interference fringes when the path difference between object and reference beam becomes comparable to D. In other words, the maximal recordable depth of a hologram is in the order of D. If one has a single longitudinal mode, then D is essentially "infinite". In practice, it is then governed by the line width of the laser emission, and this can be very small (like one Mhz, which corresponds to D=150m). When two or more modes are present, then their frequency difference delta_f is what dominates the coherence length. The mode spacing is generally given by the resonator length L, so if two modes are present, then the coherence length is approximately D=L. If three are present, then the frequency difference between the most distant modes is twice as large as before, so D=L/2. And so on... if M modes are present, then the coherence length is approximately D=L/(M-1) (this assumes, for simplification, that all the modes have equal strength). All this is illustrated by the following figure. The coherence length is measured by a [[Interferometry|Michelson Interferometer]], and given by the maximal path length difference where reasonable fringe contrast occurs. On the left various laser spectra with different longitudinal modes are shown (the dashed line symbolizes the gain profile). On the right, shown are the corresponding interference patterns that arise when translating the movable mirror (mathematically speaking, they display the [http://en.wikipedia.org/wiki/Fourier_transform Fourier transformation] of the spectrum). The important point is that the fringes blur in a way that depends on the details of the laser spectrum. [[Image:Coherencelength2.jpg]] The following scenarios are shown: <ul> <li>A: Single frequency operation - the coherence length D is basically infinite. <li>B: Two modes oscillate, so the coherence length D is basically L. Assumed is that the lines are quite close (L is large). <li>C: Again two modes oscillate, so again D=L. But here L is assumed to be small, resulting in a shorter coherence length than before. <li>D: Four modes oscillate, so D=L/3 is quite a bit shorter than before. This scenario is typical for powerful lasers with a lot of gain. </ul> For example, for a [[Types_of_Lasers#HeNe_Lasers|Helium Neon laser]], the gain window is typically 1Ghz. Assume the resonator length is L=60cm, then its mode spacing is c/(2L)=250Mhz. Thus up to four modes can be present simultaneously, and if this is the case, then D=60(4-1)=20cm. This is a reasonable value for recording most holograms. For an [[Types_of_Lasers#Argon_Ion_Lasers|argon laser]], due to the high plasma temperature the gain window is like 10Ghz. Assuming again that L=60cm, up to 40 modes can simultaneously lase, and the coherence length will be approximately D=60cm/39~1.5cm. This allows to record only very shallow holograms! Thus, an etalon is pretty much required. For a [[Types_of_Lasers#Diode_Lasers|diode laser]], the resonator length is very small, and the mode spacing can be 100Ghz. This means that the moment two or more modes lase, the coherence length drops down to a fraction of an inch. Thus, multi-frequency operation of a diode laser must be avoided by all means! In practice, the way to the determine longitudinal mode structure and coherence length of a laser is either by setting up a [[Interferometry|Michelson Interferometer]] as shown above, or by directly displaying the laser spectrum by a scanning Fabry-Perot interferometer. See [http://www.repairfaq.org/sam/laserlia.htm#liasfpi Sam's] and [http://argonholo.webhop.net/laser/SFPI.html W'] notes on home-built SFPI's. For diode lasers with a large mode spacing, the longitudinal spectrum can be most conveniently displayed by a grating based optical spectrum analyzer with sufficient resolution (better than approx 0.2nm). Such a device can be build in a simple manner by using a CD or DVD as grating, in combination with a path length of several meters. I had to add this example for calculating coherence length from the forum. From Iovine's "Homemade Holograms" p. 154: If you know the range of frequencies: CL = c / (2 * range in Hz) - c is speed of light in m/sec For a range of wavelengths: CL = (center wavelength in meters)^2 / (2 * range in meters) Example: laser diode at 670 nm with wavelength range of 0.2 nm should have a CL of (670 * 10^-9)^2 / 2 * (0.2 * 10^-9) = 0.0011 meter. =====Mode Hops ===== There are often a number of sable longitudinal modes that can exist in a laser cavity. If the laser jumps from one to the next it is called a [[Mode Hop]]. A [[Mode Hop]] will destroy a holographic image causing "banding" or "sliced bread" holograms. ====Known Lasers that work for Holography==== *Spectra Physics Model 164 with prism (single line operation) and etalon (added coherence) *Spectra Physics Model 165 with prism (single line operation) and etalon (added coherence) *Infiniter 200 Laser Pointer *Integraf Laser Diode *Coherent C315 DPSS 532nm *Lexel 85 Argon Laser with wavelength selector and [[Etalon]] *Lexel 95 Argon Laser with wavelength selector and [[Etalon]] *Most tubular black casing HeNe lasers More information about [[Types of Lasers]] is available [[Types of Lasers|here]].<br> A most detailed discussion of lasers for the amateur can be found in [http://www.repairfaq.org/sam/laserfaq.htm Sam's Laser FAQ]. bc78c530fa29d3a76d7e851bc1f4a57ed01a565e 0 411 973 972 2013-05-12T02:54:20Z Jsfisher 1 1 revision wikitext text/x-wiki ===AHD Guidlines for LASER Alignment=== From LBL The following are requirements and suggestions for the laser alignment section of a laser AHD at LBNL (note that the alignment procedures are only one part of the laser AHD). ===Laser Alignment Guidelines to Help Prevent Accidents=== *No unauthorized personnel will be in the room or area. *Laser protective eyewear must be worn. *All laser users must attend the LBNL laser safety class, EHS0280. *The individual who moves or places an optical component on an optical table is responsible for identifying and terminating every stray beam coming from that component. *To reduce accidental reflections, watches and reflective jewelry should be taken off before any alignment. *Beam blocks must be secured. *When the beam is directed out of the horizontal plane, it must be clearly marked. *A solid stray beam shield must be securely mounted above the area to prevent accidental exposure to the laser beam. *All laser users must receive an orientation to the laser use area by an authorized laser user of that area. *Laser users must have had their baseline eye examination prior to performing any alignment procedures. *The lowest possible/practical power will be used during alignments. *When possible, a course alignment should be performed with a HeNe alignment laser. *Have beam paths at a safe height, below eye level when standing or sitting, not at a level that tempts one to bend down and look at the beam. If necessary, place a platform around the optical table to raise one’s height. ===Alignment=== The techniques for laser alignment listed below will be used to help prevent accidents during alignment of the lasers covered by this AHD. ====Initial Considerations==== Access to the room/area is limited to authorized personnel only. Persons conducting the alignment have been authorized by the PI and are listed in this AHD. A NOTICE sign must be posted at entrances when temporary laser control areas are used or when unusual conditions exist that warrant additional hazard information be available to personnel wishing to enter the area. If the laser is a Class IIIb or IV open-beam system, make sure exterior warning signs/indicators are functioning. Use beam blocking barrier or laser curtain to contain beam - Use "Notice" and "Danger" signs per ANSI standards. ====Preparation==== Consider having someone present to help with the alignment. Remove watches, rings, dangling badges, necklaces, reflective jewelry, etc. before any alignment begins. The use non-reflective tools should be considered. Remove all unnecessary equipment, tools, combustible material (if fire is a possibility) to minimize the possibility of stray reflections and non-beam accidents. Skin protection should be worn on the face, hands and arms when aligning UV systems. ====Equipment preparation==== Identify equipment and materials necessary to perform alignment. Have all equipment and materials needed before beginning the alignment. This system requires the following items: tools, targets, beam stops/blocks, power meter/detector, beam profiling system, curtain, signage, caution tape, personal protective equipment (PPE): alignment eyewear, face shields for scattered UV. Pay attention to housekeeping; make sure the immediate work area/benchtop/optical table is free from opportunistic specular reflectors not need for alignment (e.g., glass bottles, razor blades, forceps, screw drivers, optical posts, photographic paper, plastic, dye cells, etc.) ====Area preparation==== Cover windows or viewing ports within the controlled area. Prepare the beam delivery system: remove beam tubes or other parts of the protective housing as necessary, including extended sections that may be covered by beam tubes or bellows; check all optics (mirrors, lenses, filters, polarizers, expanders, etc.) and optomechanical components (base plates, post holders and fasteners, mirror mounts, etc.) ensuring they are currently aligned (for changes/ additions to an existing alignment) and securely mounted. Isolate and demarcate the area to avoid distractions and minimize the hazard to others. If the high-power laser is embedded in other equipment, establish temporary laser controlled area. ====Eyewear==== Appropriate laser protective eyewear MUST be worn by all persons within the Nominal Hazard Zone (NHZ) whenever there is an open Class 3B or Class 4 beam. The NHZ is considered to be the entire room or lab in which the laser is located unless otherwise specified in the AHD. Violation of this policy is cause for a STOP WORK action. ANYONE witnessing a violation of this policy has the right and the obligation to initiate a STOP WORK action and report it to the LSO and division management. You must have the correct eyewear for your wavelength(s) and power. The LSO has authorized reduced optical density eyewear to allow the beam spot to be seen. Measures shall be taken and documented to ensure that no stray hazardous specular reflections are present before the lower OD eyewear is worn. A return to the Maximum OD eyewear as listed in the laser table will be made when the alignment is complete. The eyewear is labeled as alignment eyewear and is stored in a different location than the standard laser eyewear for this operation. ====Beam viewing==== No direct (intrabeam) viewing by eye is allowed unless specifically evaluated and approved by the LSO. Intrabeam viewing is to be avoided by using cameras or fluorescent devices. When using viewing aids to visualize the beam, reach into the beam path slowly and deliberately with the card slightly angled so you can see the diffuse reflection. Adjust the optic so that the beam strikes the card just in front of the surface of the component. Invisible beams are viewed with IR/UV cards, business cards or card stock, craft paper, viewers, 3x5 cards, thermal fax paper, Polaroid film or similar technique. Operators are aware that specular reflections off some of these devices is possible, and that they may smoke or burn. ====Beam control==== Label all areas where the beam leaves the horizontal plane. If the beam path changes elevation (+Z), be aware of the increased potential for vertical reflections. Terminate all stray or unused beams. Confine the beam to the optical table or benchtop. Be aware of the potential for errant reflections (stray beams) from components such as polarizers and dielectric mirrors. Check for stray beams at each step and again after completing all alignment steps. As you progress down the optical path, place beam blocks behind optics to be adjusted to stop errant (stray) beams. Close the shutter or insert the beam block during adjustments; resecure optics making sure components are properly located/adjusted. Make sure that the beam shutter is closed or a beam block is in front of the end window. Make sure beam block is securely mounted. If the beam path to be aligned is located in different rooms, locate a beam block in the beam path between the rooms, and align one room, then the other. If line of sight with personnel in other rooms is blocked, use two-way, real-time communications. Be patient at each step. Restore the system to normal operational mode (pay attention to the protective housing, interlock switches, and shutters) and verify normal operation. ====Light power reduction==== Perform the "rough" or coarse" alignment with the beam blocked. Reduce the beam power through the use of ND filters, beam splitters and dumps, or reducing power at the power supply. Avoid the use of high-power settings during alignment as much as is practical. If the alignment has been performed at lower power or with a low-power collinear beam but final steps will be performed at operational power levels, be sure and change to the appropriate eyewear for the high-power beam. Pulsed lasers are aligned by firing single pulses when practical. For pulsed lasers, use single pulses and/or reduce pump power. For Q-switched lasers, turn off the Q-switch and use in the low-power, CW mode For CW lasers with adjustable power, adjust the power to a minimum stable level. Co-axial low power lasers should be used when practical for alignment of the primary beam. Enclose the beam as much as practical, close the shutter as much as practical during course adjustments, secure optics/optics mounts to the table as much as practical, secure beam stops to the table or optics mounts. If the primary laser is optically pumped by another laser and alignment of the pump beam is necessary, block the primary beam to limit potential multi-wavelength exposure/eyewear concerns, align the pump beam, and then replace beam enclosure in the pump-to-laser beam path. cb3b16c6343c8990426314df631c40993ba123f1 0 412 975 974 2013-05-12T02:54:21Z Jsfisher 1 1 revision wikitext text/x-wiki I am working on an article for this. - Colin cd0e9095f8570a0f52c686bdd77c16ae88b1a5ef 0 413 977 976 2013-05-12T02:54:21Z Jsfisher 1 1 revision wikitext text/x-wiki '''Laser Safety.''' [http://www.repairfaq.org/sam/lasersaf.htm#saftoc Laser Sam's Laser Safety] is a must read! [[Laser Alignment Safety]] from LBL. ==Eye Hazards== [[Image:TheEye.gif]] Most importantly, any laser, even a 1/2 milliwatt laser pointer can be dangerous to [[The Eye]]s. Never point a laser directly in anyone's eye. Also it is very easy to catch a laser reflection off of something into your eye. Wear Laser protective glasses whenever possible and avoid directing the beam to any shiny surfaces. When a laser beam reflects off a flat surface it becomes a spot that your eye must avoid. When it reflects of a cylindrical surface it becomes a line. While, it is a lower power density it is also large and harder to avoid. If you reflect off a spherical surface it becomes a very large object to avoid. Try, whenever posible, to make any mounts black and aim optics at the lowest power possible. Higher power lasers (generally 5 Mw or more) should have a time delay connected to the ON switch. Often a key is required to prevent the high power laser from accidentally being activated. When using high power lasers, turn the energy down as low as possible when aligning optics. ===Eye Hazards for Pulsed Lasers=== It is important to calculate the maximum power density of the object beam when making a pulsed portrait. Use large diffuser plates to enlarge the light source. Here is some more information about [[The Eye]]. ===Infra-Red Eye Hazards=== Holographic lasers can be sources of 808nm light, 1064nm light in both continuous and pulsed modes. Most people can not detect any light at these frequencies. This makes verifying a non-function laser quite important. It is conceivable that light is emanating from a laser that appears dead. The 532nm beam can be contaminated with IR light in some circumstances. Mirrors can be designed to reflect the 1064nm light and not the 532nm light (or visa versa). It is important to send any un-wanted IR light to a beam dump. ===Flash Lamp Eye Hazzards=== Flash Lamps can emit light from the UV to the Far IR. This light is very short but can cause considerable damage. Always shield flash lamps for testing. This helps protect from light and from lamp explosion. '''Do not operate flash lamps without a guard.''' ==Electrical Hazards== Quite a few laser use high voltage power supplies. Know your laser and it's power supply. Even some small HeNe lasers use high voltage capacitors that can discharge even when the laser is unplugged. Practice [[Safe Electrical Procedures]]. Grounding is a very important aspect of safety in power supplies. Frayed cables, loose parts, motor or coil windings can be a source for an electrical fault. (metal etc becoming energized with voltage) With proper grounding this will cause a short as the ground takes the current back without much resistance which will trip a circuit breaker either in the unit or building. Unfortunately, some buildings may not be wired correctly regarding ground safety or the wall outlet may not actually have a ground wire that runs back to the electrical circuit ground point and earth ground. Such ungrounded conditions will allow the voltage to remain present and if you become grounded by some condition and you become part of that path then you will take the current load. Additionally high voltage (HV) used in the laser system also for the same reason should be grounded so that if a fault occurs it's current will induce a load that causes the power supply to disconnect via it's circuit breakers. It is the voltage difference that causes current to flow and you don't want to be in that path, so it's best to have the laser head hard grounded (at the same equip-potential) to the power supply and the power supply hard grounded to the building etc so that any faults trips breakers which prevent fires and hopefully electrocutions. Ground fault interrupters are better at breaking the current sooner since they operate at milliamp levels of current on the ground wire. More information about GFI at Sam's [http://www.codecheck.com/gfci_principal.htm GFI] Always design circuits that have large capacitors so they automatically discharge if left unused. A 1000V potential will easily jump 1cm. A 3000V potential will jump 3cm. [[http://www.lbl.gov/ehs/pub3000/CH08.html LBLs excellent guide for electrical safety]] ===How Much Current is Dangerous?=== *'''Electrical Current''' -- '''Biological Effect''' *1 mA threshold for feeling *10-20 mA voluntary let-go of circuit impossible *25 mA onset of muscular contractions *50-200 mA ventricular fibrillation or cardiac arrest ===Types of Damage Caused by Electrical Hazards=== From LBL. ====Electrical Shock==== Accidental contact with EXPOSED electrical parts operating at a VOLTAGE greater than 50 volts to ground, and having a current greater than 5 milliamperes, can cause serious injury or death. Fatal ventricular fibrillation of the heart can be triggered by a current flow of as little as several milliamperes. Severe injuries, such as deep internal burns, can occur even if the current does not pass through the vital organs or nerves. ====Delayed Effects==== Damage to the internal tissues may not be apparent immediately after contact with the current. Delayed internal tissue swelling and irritation are possible. Prompt medical attention can help minimize these effects and avoid death or long-term injury. ====Arc-Flash==== When an electric current passes through the air between two conductors, the temperature can reach 35,000°F. Exposure to these extreme temperatures can result in life threatening burns. The majority of hospital admissions due to electrical accidents are from arc-flash burns, not electrical shocks. Arc-flashes can and do kill at distances in excess of 10 ft. ====Arc Blast==== The tremendous temperatures of the arc cause an explosive expansion of both metal and the surrounding air in the arc path. For example, copper expands by a factor of 67,000 times when changed from a solid into a vapor. The dangers of this explosion are of high blast pressure wave, high decibel levels of sound and high velocity shrapnel. Finally the material and molten metal is expelled away from the arc at speeds exceeding 700 miles per hour. Arc blasts often cause severe injuries and death. ====Other Burns==== Other burns suffered in electrical accidents are of two basic types: electrical burns and thermal contact burns. In electrical burns, tissue damage (whether skin deep or deeper) occurs because the body is unable to dissipate the heat caused by the current flow. Typically, electrical burns are slow to heal. Thermal contact burns are those normally experienced from skin contact with the hot surfaces of overheated electric conductors. ===Proper Procedures for Clearing High Voltage Circuits=== ===Proper Procedures for Testing Live High Voltage Circuits=== ===Laser Sam's Safety Tips for High Voltage Work=== *Author: Samuel M. Goldwasser *Copyright (c) 1994, 1995, 1996, 1997, 1998 All Rights Reserved Reproduction of this document in whole or in part is permitted if both of the following conditions are satisfied: *This notice is included in its entirety at the beginning. *There is no charge except to cover the costs of copying. ------ The purpose of this set of guidelines is not to frighten you but rather to make you aware of the appropriate precautions. Repair of TVs, monitors, microwave ovens, and other consumer and industrial equipment can be both rewarding and economical. Just be sure that it is also safe! *Don't work alone - in the event of an emergency another person's presence may be essential. *Always keep one hand in your pocket when anywhere around a powered line-connected or high voltage system. *Wear rubber bottom shoes or sneakers. An insulated floor is better than metal or bare concrete but this may be outside of your control. A rubber mat should be an acceptable substitute but a carpet, not matter how thick, may not be a particularly good insulator. *Wear eye protection - large plastic lensed eyeglasses or safety goggles. *Don't wear any jewelry or other articles that could accidentally contact circuitry and conduct current, or get caught in moving parts. *Set up your work area away from possible grounds that you may accidentally contact. *Have a fire extinguisher rated for electrical fires readily accessible in a location that won't get blocked should something burst into flames. *Use a dust mask when cleaning inside electronic equipment and appliances, particularly TVs, monitors, vacuum cleaners, and other dust collectors. *Know your equipment: TVs and monitors may use parts of the metal chassis as ground return yet the chassis may be electrically live with respect to the earth ground of the AC line. Microwave ovens use the chassis as ground return for the high voltage. In addition, do not assume that the chassis is a suitable ground for your test equipment! *If circuit boards need to be removed from their mountings, put insulating material between the boards and anything they may short to. Hold them in place with string or electrical tape. Prop them up with insulation sticks - plastic or wood. *If you need to probe, solder, or otherwise touch circuits with power off, discharge (across) large power supply filter capacitors with a 2 W or greater resistor of 100 to 500 ohms/V approximate value (e.g., for a 200 V capacitor, use a 20K to 100K ohm resistor). Monitor while discharging and/or verify that there is no residual charge with a suitable voltmeter. In a TV or monitor, if you are removing the high voltage connection to the CRT (to replace the flyback transformer for example) first discharge the CRT contact (under the insulating cup at the end of the fat red wire). Use a 1M to 10M ohm 1W or greater wattage resistor on the end of an insulating stick or the probe of a high voltage meter. Discharge to the metal frame which is connected to the outside of the CRT. *For TVs and monitors in particular, there is the additional danger of CRT implosion - take care not to bang the CRT envelope with your tools. An implosion will scatter shards of glass at high velocity in every direction. There is several tons of force attempting to crush the typical CRT. Always wear eye protection. While the actual chance of a violent implosion is relatively small, why take chances? (However, breaking the relatively fragile neck off the CRT WILL be embarrassing at the very least.) *Connect/disconnect any test leads with the equipment unpowered and unplugged. Use clip leads or solder temporary wires to reach cramped locations or difficult to access locations. *If you must probe live, put electrical tape over all but the last 1/16" of the test probes to avoid the possibility of an accidental short which could cause damage to various components. Clip the reference end of the meter or scope to the appropriate ground return so that you need to only probe with one hand. *Perform as many tests as possible with power off and the equipment unplugged. For example, the semiconductors in the power supply section of a TV or monitor can be tested for short circuits with an ohmmeter. *Use an isolation transformer if there is any chance of contacting line connected circuits. A Variac(tm) (variable autotransformer) is not an isolation transformer! However, the combination of a Variac and isolation transformer maintains the safety benefits and is a very versatile device. See the document "Repair Briefs, An Introduction", available at this site, for more details. *The use of a GFCI (Ground Fault Circuit Interrupter) protected outlet is a good idea but may not protect you from shock from many points in a line connected TV or monitor, or the high voltage side of a microwave oven, for example. (Note however, that, a GFCI may nuisance trip at power-on or at other random times due to leakage paths (like your scope probe ground) or the highly capacitive or inductive input characteristics of line powered equipment.) A GFCI is also a relatively complex active device which may not be designed for repeated tripping - you are depending on some action to be taken (and bad things happen if it doesn't!) - unlike the passive nature of an isolation transformer. A fuse or circuit breaker is too slow and insensitive to provide any protection for you or in many cases, your equipment. However, these devices may save your scope probe ground wire should you accidentally connect it to a live chassis. *When handling static sensitive components, an anti-static wrist strap is recommended. However, it should be constructed of high resistance materials with a high resistance path between you and the chassis (greater than 100K ohms). Never use metallic conductors as you would then become an excellent path to ground for line current or risk amputating your hand at the wrist when you accidentally contacted that 1000 A welder supply! *Don't attempt repair work when you are tired. Not only will you be more careless, but your primary diagnostic tool - deductive reasoning - will not be operating at full capacity. *Finally, never assume anything without checking it out for yourself! Don't take shortcuts! [http://www.repairfaq.org/REPAIR/F_tshoot.html More great inforamtion from Laser Sam's!] ==Causes of Laser Accidents== '''Some Common Causes of Laser Accidents from LBL.''' *Not wearing protective eyewear during alignment procedures *Not wearing protective eyewear in the laser control area *Misaligned optics and upwardly directed beams *Equipment malfunction *Improper methods of handling high voltage *Available eye protection not used *Intentional exposure of unprotected personnel *Lack of protection from nonbeam hazards *Failure to follow the AHD *Bypassing of interlocks, door, and laser housing *Insertion of reflective materials into beam paths *Lack of preplanning *Turning on power supply accidentally *Operating unfamiliar equipment *Wearing the wrong eyewear ==Laser Classes== [http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?FR=1040.10 Laser Classification Law] ===Class I=== Laser usually contained within the product and considered non- hazardous. Laers are less than .4 mw and require no labeling. Laser printers, CD players, DVD players ===Class II=== Visible laser or laser system that cannot cause eye damage unless viewed directly for an extended period of time, or with magnifiers, binoculars, or telescopes. Laser power .4 mw to 1mw. Bar code scanners ===Class IIa=== Laser Power is less than 1mw. Labled: Caution - Do not stare into beam. ===Class IIIa=== Laser that normally does not present a risk of injury if viewed momentarily with an unaided eye, but may present a greater risk if viewed using magnifiers, binoculars, or telescopes. Laser Power < 5 mw. Labled:CAUTION - Laser Radiation - Do Not Stare into Beam or View Directly with Optical Instruments. Laser pointers ===Class IIIb=== Laser can cause eye damage if viewed directly. Laser power < 500 mw. Labled: DANGER - Laser Radiation - Avoid Direct Exposure to Beam Laser light shows, Industrial lasers, Research lasers. ===Class IV=== Laser may cause severe eye injury with short duration exposure to the direct or reflected beam. May also cause severe skin damage and present a fire hazard. Laser Power: > 500 mw. Labled - DANGER - Laser Radiation - Avoid Eye or Skin Exposure to Beam. Laser light shows, Industrial lasers, Research lasers ==Lasers and the FDA== All laser devices distributed for both human and animal treatment in the U.S. are subject to Mandatory Performance Standards. They must meet the Federal laser product performance standard and must submit an "initial report" to CDRH's Office of Compliance prior to distributing the product (see 21 CFR 1000-1040.11). This performance standard specifies the safety features and labeling that all laser products must have in order to provide adequate safety to users and patients. A laser product manufacturer must certify that each model complies with the standard before introducing the laser into U.S. commerce. This includes distribution for use during clinical investigations prior to device approval. Certification of a laser product means that each unit has passed a quality assurance test and that it complies with the performance standard. The firm that certifies a laser product assumes responsibility for product reporting, recordkeeping, and notification of defects, noncompliances, and accidental radiation occurrences, as specified in sections 21 CFR 1000-1010. A certifier of a laser product is required to report the product via a Laser Product Report submitted to CDRH. Reporting guides and related regulatory information are available from the DSMA web site at: http://www.fda.gov/cdrh/devadvice. Distribution of any certified laser products internationally would also require submission of the report. '''FDA's Authority''' The FDA has the authority to regulate all kinds of lasers. Under the Medical Device Amendments to the Federal Food, Drug, and Cosmetic Act, the agency regulates lasers used in medicine. And under the Electronic Product Radiation Control Provisions of the act, the FDA regulates both medical and nonmedical lasers such as those used to solder circuits in factories, to scan groceries in a supermarket, or to entertain a crowd with a light show in the night sky. The FDA may inspect manufacturers of laser products and require the recall of products that don't comply with federal standards or that have radiation safety defects. The agency also may test laser products and inspect displays of laser light shows to ensure the public is protected. Producers of laser light shows are required to tell the FDA where they are planning a display so that the agency can inspect it if possible and take action if required. In 1995, the FDA, working with the Federal Aviation Administration, issued a moratorium that remains in effect on outdoor laser light shows in and near Las Vegas. The action, which affects Clark County, Nev., was taken after airline pilots reported experiencing temporary visual impairment during flights into or out of the county's three airports. The FDA requires that labeling on most laser products contain a warning about radiation and other hazards and a statement certifying that the laser complies with FDA safety regulations. The label must also state the power output and the hazard class of the product. The FDA recognizes four major hazard classes (I to IV), including two subclasses (IIIa and IIIb), of lasers--ranging from those that pose no known hazard to those that pose serious danger if used improperly. The higher the class, the more powerful the laser. Class I laser products, for example, include laser printers and CD players, which are not considered hazardous because the laser radiation is contained within the product. Class IIIb and class IV laser products are very powerful and permit ready access to the laser radiation, which can cause eye or skin injury. Research and industrial lasers and laser light show projectors fall into these classes. Class IIIb and class IV laser light show projectors may be sold only by or to individuals or firms that have obtained approval from the FDA. b005edc7417ddcb5733b48019d0935ee1a42bd71 0 414 979 978 2013-05-12T02:54:21Z Jsfisher 1 1 revision wikitext text/x-wiki Tools Needed: * Nice feature to have is quick change tool post. * Indexable cutter set; 5 piece holder set with different orientations of the indexable cutter bits. * Drill chuck/drills for tail piece. Smaller end mills also can be used. * 1/16" cutoff blade and holder. * Boring bars and holders. If you get a quick change tool post, these usually come with 5 different holders. Make an optic adapter. Place some round stock in the 3 jaw lathe chuck and tighten. Face the end of the part by using an indexable cutter across the face. Run a cutter along the outside diameter cutting 20 to 40 thousands off aluminum per pass. Just before the OD is reached with 10 thousands make a slow good clean pass to provide a better finish. Chuck up in the tail piece a drill and bore into the face of the part. Use progressively larger drills or end mills to get to the ID you want. If a tool is not close enough, then use a Boring bar to shave off the last little bit of ID. Use a cutoff blade tool slowly and give yourself time by pulling in and out the blade to make sure it is not wandering off at an angle or snags and breaks. Place the part in a drill press with an X Y table and drill a set screw hole or use a Mill for the same job. Hand tap the hole and place a nylon tip set screw in for the optic adapter. Square holes will require the mill and small end mills inorder to fabricate. 5cb4fea4f745f094cd77b1e5fd9a054d2f26bda1 0 415 981 980 2013-05-12T02:54:21Z Jsfisher 1 1 revision wikitext text/x-wiki ==What is Light?== ==Learning About the Spectrum== ==Is Light a Wave?== Young's Double Slit Experiment. ==Learning About Interference== ==How Does a Laser Work?== bc482e8c7ea2e1eeb82418ada7148194add195da 0 416 983 982 2013-05-12T02:54:22Z Jsfisher 1 1 revision wikitext text/x-wiki Lenses are very useful for holography. Small lenses can be used to expand the beam, to change the diameter of the beam and to change the height to width ratio of the beam. The best lenses are [http://en.wikipedia.org/wiki/Optical_coating Anti-Reflection] coated for the frequency of laser/s in use. Large lenses can be used to collimate a laser beam or to form a real image to make image planed holograms. [[Cleaning Lenses]] ====Choosing the Correct Lens==== '''From Tom B.''' Let beam diameter d be 4 mm and lens focal length f be 5 mm, The beam is brought to a focal point f mm past the lens, and in cross section looks like an isoceles triangle with the acute angle A at the focus. The half-angle hA of the right-triangle part of the cone is given by hA = arctan ((d/2)/f) = arctan (2/5) = arctan(0.4) = 21.8 degrees. Past the focus, the beam diverges at 2 * hA. For a given distance past focus L, the beam radius R is L * tan(hA), or L = R / tan(hA) For the given diameter D of 100 mm, R is 50 mm, and L = 50 mm / tan(21.8) = 50/0.4 = 125 mm So if we have an 8" collimation mirror, and we have a 4mm laser beam with no divergence and we want a colliated out beam then we would choose a lens with the focal length: working... ====Spherical==== This is the most common shape for a lens. It has one or both surfaces ground to a spherical surface. It can either be concave or convex. They suffer from spherical aberrations but this is not important in many applications. Plano-convex lenses have a positive focal length defined by f=R/(n-1) where R is the radius of curvature and n is the index of refraction of the glass used. Plano-concave lenses have a negative focal length defined by f=-R/(n-1). Bi-Convex lenses have a positive focal length defined by f=((2(n-1)/r)-(Tc(n-1)^2)/nR^2))^-1. Where Tc is the overall thickness of the lens. Bi-Concave lenses have a negative focal length defined by f=-((2(n-1)/r)-(Tc(n-1)^2)/nR^2))^-1. ====Cylindrical==== Cylindrical lenses are only ground on one axis. If placed into a laser beam they only expand one axis forming a line. With two lenses you can circularize an elliptical beam. If the ratio of the beam width to height is 3 to 1 then the focal lengths of the correcting lenses must be 3 to 1 (ie. 75mm and 25mm). The lenses are then placed at f1+f2 distance apart (ie. 100mm). Cylindrical lenses are also useful before the collimating optic in order to make a slit reference beam. Holographic stereograms and Rainbow Holograms are examples of where a cylindrical lens could be useful. ====Aspheric==== Aspheric lenses are ground to a special figure that corrects for [[Optics Aberrations|spherical aberrations]]. ====Objectives==== Microscope objectives are often used in spatial filters. They work best if AR coated to the wavelength of the laser in use. You can convert from focal length to magnification with the following formula: M = 250 / f or f = 250 / M where M is the magnification of the objective and f is the focal length of the lens. [http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=1922&search=1Edmund Industrial Optics] makes a laser line series of objectives that have very low losses at 632nm. ====GRIN Lenses==== Gradient Index Lenses have no figure cut into them. The focusing ability comes from changing the index of refraction across the surface of the lens. They are often used to focus light from a 808nm diode into the end of a YAG crystal for a DPSS laser. They are produced by silver-ion exchange (or lithium-ion exchange for low numerical apertures) in a special glass. GRIN lenses come in two basic flavors: RADIAL or AXIAL which are sometimes referred to as RGRIN and AGRIN respectively. RGRINS are usually used where you want to add optical power to focus light. An RGRIN with flat surfaces can focus light just as a normal lens with curved surfaces does. Thin RGRIN lenses with flat surfaces are known as WOOD lenses, named after the American physicist R.W. Wood who did a lot of experimental work with radial gradients from about 1895 to 1905 and included descriptions of how to make them in his physics text book (available from [http://www.osa.org/ OSA]). GRIN Math: The Eikonal equation (Born & Wolf) says that d(nk)/ds = gradient n where nk is the ray vector, s is the distance along the direction of propagation, and n is the refractive index. So moving to finite differentials gives delta(nk) = delta(s) * gradient n For Example, gradient n = (1.355 - 1.300) / 15 mm = 0.0037 per mm so delta(s) * gradient n = 5.5 mm * 0.0037 /mm = 0.0202 Now remember that nk is along the horizontal direction with a magnitude of 1.300 and delta(nk) is perpendicular to it, pointed toward the optical axis. Thus the vector sum of ray vector and change to the ray vector will have an angle of tangent (0.020/1.300) = 0.89 degrees in the glass In air, Snell's law says that this angle will increase to inverse sine(1.300*(sine(0.89 degrees)) = 1.15 degrees. So the ray exits at a height of about 15 mm with a slope of 1.15 degrees; this means it will strike the optical axis at a distance of 15 mm / tan(1.15 degrees), which is 747 mm. Which isn't the 409 mm you got f9a2945eef51846e379eabc6422fa01f77c159d4 0 417 985 984 2013-05-12T02:54:22Z Jsfisher 1 1 revision wikitext text/x-wiki It is easiest to use your light meter perpendicular to the beam you are measuring. Read this [[Calculating Ellipses|discussion]]. ====Science and Mechanics==== This is the light meter recomended in "Holography Handbook" and is no longer being made. Once and a while they are available used. They work well and are inexpensive. Their biggest advantage is you can use the readings and directly try the projects in "Holography Handbook" however since AGFA is no longer being made it is not that important anymore. ====Andover Holography HP-1==== [[Image:HP1a.jpg]] The HP-1 is a new lightmeter designed using current technology expressly for use in the making of holograms. It was designed to fill the void left by the Science & Mechanics meter. The HP-1 is a precise hand-held instrument for measuring light and exposure levels for holography. It measures CW laser light over a wide range of power levels from microwatts to over 100 milliwatts. Using the supplied photocell, the HP-1 provides real time readings of light levels. Readings can be taken separately for the reference and object beams, and the HP-1 will compute and display the beam ratio and total power. The HP-1 can also compute optical density (OD) based on two readings. Sporting a two-line alphanumeric character display, the HP-1 provides trending of real time readings which makes it easy to adjust optics, mirrors, lasers, or spatial filters for maximum performance. The battery powered HP-1 comes with a large area (8 cm^2) photocell, which is calibrated for 632.8 and 532 nm. The sensor is thin (<1/8") which makes it easy to position in the film plane.The HP-1 can be custom calibrated for most silicon photodetectors operating in the photovoltaic mode at a variety of wavelengths. For more information, see this link: [http://holographyforum.org/phpBB2/viewtopic.php?t=4429 HP-1 thread on forum] ====Coherent LaserCheck==== [[Image:LaserCheck.jpg]] *Hand-held laser power meter *Integrated sensor *Auto-ranging with peak sample-and-hold *Power measurement from 0.5 µW-1W *±5% calibrated accuracy from 400-1064 nm The LaserCheck is micro-processor controlled with wavelength correction, auto-ranging (µW or mW displayed), power overload warning and automatic shutoff. At higher powers the embedded silicon photodiode is protected from saturation with a built-in optical attenuator. ====SPER Power Meter==== [[Image:SPER2.jpg]] From the [http://www.sperscientific.com/ SPER web site] These tiny meters are less than 3/4” thick, weigh only 4oz (120g) and are easily carried in a shirt pocket. The controls, display and sensor are all neatly contained and protected within the folding case. Directions are printed right inside the cover. When open, the sensor may be extended for remote use or snaps into a fixed position atop the case. All units feature relative temperature, min-max, bar graph display, auto power off, hold functions and indicate low battery and over range. Powered by 2 button cell batteries (included). Meter Dimensions: 4.5” x 3” x 3/4” (177 x 76 x 18mm). *Range: Calibrated at 633 nm but can also read any other wavelength in the 400~1100 nm range using a chart inside the case cover. *Resolution: 40.00 uW, 400.0 uW, 4.000 mW, 40.00 mW *Accuracy: +/-5%@calibrated, wavelength 633 nm / 1mW *Features:Max-Min *Cord length:15" *Probe Dim: 3½" x ½" x ½" (84 x 16 x 10mm) *Operating Temp: 0~40ºC *Operating RH: 80% non condensing, maximum With the specs out of the way, how well does this meter work for holography? Very well. It holds calibration well and is easy to use with non-633nm lasers (at least it is with 532nm). The conversion chart makes it easy to figure the ballpark power output for laser not at 633nm and with the four scales it also makes a good meter for computing exposure times. ====Simple Homebuilt Exposure Meter==== [http://perso.wanadoo.fr/redlum.xohp/electronics/lightmeter.html Wler's Light Meter Web Page] ====Homemade power meters==== If you have a solar cell and a Ohm Meter that will read current then you simply need to connect them together. The output of a solar cell is linearly proportional to the light hitting the surface. There is no way to calibrate it but you will be able to get relative measurements quite easily. It is quite important that you do not try to read voltage as that is not a linear relationship. ====Thermopiles==== Here's something you might be interested in. I just bought a thermopile meter for 300 bucks. New surplus. More are available. In case some of you don't know what a thermopile meter is I'll explain. Most of our meters have a silicon detector or something like that. Perfect for expanded and diffuse beams but if you put a laser of any real power into it the sensor would be burnt out. Also they are small sensors, It's usually impossible to get the entire raw beam into the active area. The disk on this thermopile is 1/2 inch large. More than enough to get any holography laser into the sensor area. A thermopile is a bunch of thermocouples in series. A thermocouple is two different metals connected, when heat is applied to that junction a voltage is produced. Thermoelectric power. When you shine a laser on the sensor disk in the thermopile it makes a voltage relative to the heat the laser is producing. It compares the target disk to the outside housing. The temp difference between the two is heat produced by the laser. A decent thermopile is a lot of cash, the standard is the Coherent model. The sensor is 950 bucks plus the meter. There's another company called Ophir that also makes them. New they are 650 bucks, for only the sensor. The nice thing about a thermopile is it's a broadband device, no conversions to read different wavelengths and it can handle watts of power. Pretty much any non pulsed laser we use for holography can be read with this without error, math or wavelength selector knobs. The ophir head puts out 1 millivolt for every milliwatt of laser energy put into it. So all you really need to use it is a volt meter and a power supply to run it. If you get just a thermopile from somewhere like ebay you'll need a split power supply to run it. This Ophir model uses +12 and -12 volts dc. The finished meter I got has a dc to dc converter inside so all you need is the wall wart they supply with it. Some of the ophir heads were put on the surplus market, new units. They were all bought up by a few people producing meters and selling them on forums. I got this one http://laserpointerforums.com/f64/new-5-watt-laser-power-meter-50226.html Here's a review of it http://laserpointerforums.com/f52/lpm-ophir-sensor-nospin-awesome-50064.html and here's my youtube video of mine with a 5mw red and a 150mw green. http://www.youtube.com/watch?v=5euXRzzwmXs The accuracy of this kind of meter is not in the display, it's the sensor itself. It contains a low noise op amp and the circuity to make this work. The display is just an off the shelf volt meter module in a box, so don't worry about the homemade style of this meter. It should be as accurate as any 1500 dollar meter you can buy. Jeff Weil NorthBeach Holography Inc. 5e0c43b0c01a2a193ec22d71064b91904d90013e 0 418 987 986 2013-05-12T02:54:23Z Jsfisher 1 1 revision wikitext text/x-wiki LIGHT SCIENCE Physics and the Visual Arts, by Thomas D. Rossing and Christopher J. Chiaverina, Springer-Verlag, New York, 1999, ISBN 0-387-98827-0. Like Seeing the Light, this book promises to be an Everyman’s guide to optics with particular attention to the visual arts. (A discussion of whether or not to restore the Mona Lisa is included!) A lot of ground is covered without rigorous mathematics. There is a 61 page appendix of demonstrations that the student can do at home. There are 225 illustrations, about 80 in color. It is a much more up to date book than Seeing the Light, being published more than 10 years later. Photography, holography, and digital imaging each have their own chapters. Both of the authors are Physics teachers, Rossing at Northern IllinoisUniversity, Chiaverina at New Trier High School in a suburb of Chicago. But the writing style is rather tedious, which is probably due more to Chiaverina rather than Rossing, since his Science of Acoustics book doesn’t bog down like this one. Still if you were to have one book on your shelf that answers questions in general optics this would be a good choice. A must get, although pricey! -Ed Wesly 4236504f872c3bf95dad9876cc0601a9ceeca3a6 0 419 989 988 2013-05-12T02:54:23Z Jsfisher 1 1 revision wikitext text/x-wiki '''Papers on Lippmann Photography:''' Collected and Scanned by Martin. *[http://www.designerinlight.com/lippmann/Lippmann1891.pdf Lippmann CR 1891] *[http://www.designerinlight.com/lippmann/Lippmann1892.pdf Lippmann CR 1892] *[http://www.designerinlight.com/lippmann/Lippmann_photographie_Revue_scientifique_1884.pdf Lippmann photographie Revue scientifique 1894] - Scientific Revue Photographs *[http://www.designerinlight.com/lippmann/Usagin_engl.pdf English Translation of Usagin's 1902 article. Translated by Evgeniy Borozniak.] *[http://www.designerinlight.com/lippmann/Lippmann_On_Colour_Photography_1897.pdf Lippmann On Colour Photography by the Interferential Method], Proceedings of the Royal society of London,1897 *[http://www.designerinlight.com/lippmann/Presentation_de_Lippmann_Photographies_en_couleurs_du_spectre_negatives_par_transmission_1905.PDF Lippmann, Photographies en couleurs du spectre négative par transmission], Soc. Française de Physique, 1905 - Photographs colors of the spectrum negative by French transmission, Ploughshare of Physics *[http://www.designerinlight.com/lippmann/Lippmann_Photo_interferencielle_1906.PDF Lippmann Photo interférencielle CR 1906] - Interference Photographs *[http://www.designerinlight.com/lippmann/Lippmann_Des_divers_principes_sur_lesquels_on_peut_fonder_la_photographie_directe_des_couleurs_CR_1906_Tome_CXLIII.PDF Lippmann, Des divers principes sur lesquels on peut fonder la photographie directe des couleurs, CR 1906] Tome CXLIII - Various principles on which one can base the direct photography of the colors *[http://www.designerinlight.com/lippmann/Lippmann_Nobel_lecture_1908.pdf Lippmann, Nobel lecture 1908] *[http://www.designerinlight.com/lippmann/Becquerel_Sur_la_communication_de_M_Lippmann_1891.pdf Becquerel, Sur la communication de M. Lippmann, CR 1891] - On the communication of Mr. Lippmann *[http://www.designerinlight.com/lippmann/Ives_Present_condition_of_color_photography.pdf Ives Present condition of color photography, 1912] *[http://www.designerinlight.com/lippmann/Neuhauss_Paper.pdf Richard Neuhauss' Paper] Transcribed by Martin. *[http://www.designerinlight.com/lippmann/Labatut_Labsorption_et_la_photographie_des_couleurs_1891.pdf Labatut, L'absorption et la photographie des couleurs, CR 1891] - The absorption and the photography of the colors *[http://www.designerinlight.com/lippmann/La_decouverte_de_M_Lippmann_article_anonyme_1891.pdf Anonymous, La découverte de M. Lippmann, Les annales politiques et littéraires, 1891] - The discovery of Mr. Lippmann, political records and literary *[http://www.designerinlight.com/lippmann/Meslin_Sur_la_photographie_des_couleurs_1892.pdf Meslin Sur la photographie des couleurs, CR 1892] - Meslin On the photography of the colors *[http://www.designerinlight.com/lippmann/Meslin_Sur_les_interferences_prduites_1906.pdf Meslin, Sur les interférences prduites, CR 1906] - Meslin, On the interferences preduites *[http://www.designerinlight.com/lippmann/La_photographie_des_couleurs.pdf Ruckert, La photographie des couleurs, Paris 1900] - The photography of the colors *[http://www.designerinlight.com/lippmann/Presentation_de_Lippmann_Photographies_en_couleurs_du_spectre_negatives_par_transmission_1905.pdf Presentation de Lippmann Photographies en couleurs du spectre negatives par transmission 1905] *[http://www.designerinlight.com/lippmann/Presentation_de_Rothe_Photographies_en_couleurs_obtenues_par_la_methode_interferentielle_sans_mirioir_de_mercure_1904.pdf Présentation de Rothé, Photographies en couleurs obtenues par la méthode interférentielle, sans mirioir de mercure, CR 1904] - Photographs colors obtained by the interferential method, without mirror of mercury *[http://www.designerinlight.com/lippmann/Ponsot_Photo_interferentielle_et_polarisation.PDF Ponsot Photo interférentielle et polarisation, CR 1906] *[http://www.designerinlight.com/lippmann/Leroy_Preparation_et_sensitometrie_de_plaques_photographiques_a_grain.pdf Leroy, Préparation et sensitométrie de plaques photographiques à grain très fin, 1929] - Preparation and sensitometry of photographic plates with very fine grain *[http://www.designerinlight.com/lippmann/HBLippmannPhotography.pdf Bjelkhagen on Lippmann Photography] *[http://www.designerinlight.com/lippmann/An_experimental_study_of_the_Lippmann_color_photograph_1908.pdf An experimental study of the Lippmann color photograph 1908] by Herbert E. Ives. *[http://www.designerinlight.com/lippmann/Die_Farbenphotographie.pdf Die Farbenphotographie] by Neuhauss, 1898. *[http://www.designerinlight.com/lippmann/Die_Photographie_in_naturlichen_Farben.pdf Die Photographie in naturlichen Farben] by Eduard Valenta, 1912 *[http://www.designerinlight.com/lippmann/Die_Photographie_in_naturlichen_Farben.pdf Die Photographie in naturlichen Farben] by Maximimilan Engstler, 1904 *[http://www.designerinlight.com/lippmann/Extrait_de_La_photographie_et_la_photochimie.pdf Extrait de La photographie et la photochimie] by G.-H. Niewenglowski, 1897 *[http://www.designerinlight.com/lippmann/Innerer_Bau.pdf Innerer Bau] by F. Schütt, 1895 *[http://www.designerinlight.com/lippmann/La_photographie_des_couleurs.pdf La photographie des couleurs] by Alphonse Berget, 1901 *[http://www.designerinlight.com/lippmann/Lippmann_On_Colour_Photography_1897.pdf Lippmann_On_Colour_Photography_1897] *[http://www.designerinlight.com/lippmann/Lippmann_Photographies_en_couleurs_du_spectre_nogatives_par_transmission_1905.pdf Lippmann Photographies en couleurs du spectre nogatives par transmission 1905] has been published in the CR 1905. *[http://www.designerinlight.com/lippmann/Lippmann_Photo_interferencielle_1906.PDF Des divers principes sur lesquelles on peut fonder la photographie directe des couleurs, CR 1906] *[http://www.designerinlight.com/lippmann/Manuel_de_photochromie_interferentielle.pdf Manuel de photochromie interferentielle] by A. Berthier, 1895 [[Manual of Interfermetric Photography]] *[http://www.designerinlight.com/lippmann/Nachweis.pdf Nachweis] by R. Neuhauss, 1898 *[http://www.designerinlight.com/lippmann/Sur_la_theorie_de_la_photographie_des_couleurs_simples.pdf Sur la theorie de la photographie des couleurs simples] by Gabriel Lippmann *[http://www.designerinlight.com/lippmann/The_structure_of_Lippmann_heliochromes.pdf The structure of Lippmann heliochromes] by Santiago Ramón y Cajal, 1907 *[http://www.designerinlight.com/lippmann/Three_colour_interference_pictures_1907.pdf Three_colour_interference_pictures_1907] by Herbert E. Ives, 1907 *[http://www.designerinlight.com/lippmann/Traite_pratique.pdf Traite pratique] by G.-H. Niewenglowski, 1909 *[http://www.designerinlight.com/lippmann/Uber_die_Farbenwiedergabe.pdf Uber die Farbenwiedergabe] by Reinhold Aron, 1915 *[http://www.designerinlight.com/lippmann/uber_eine_neue_kornlose_Platte.pdf uber eine neue kornlose Platte] by Hans Lehmann, 1907 *[http://www.designerinlight.com/lippmann/Uber_ein_Badeverfahren.pdf Uber ein Badeverfahren] by Raphael E. Liesegang, 1915 *[http://www.designerinlight.com/lippmann/Ursache_und_Beseitigung_eines_Fehlers.pdf Ursache und Beseitigung eines Fehlers] by Otto Wiener, 1899 *[[Sogokon Article|Lippmann Photograph by Sogokon' A. B. ]] is reprinted from a Russian article originally scanned by Aleksandr. It was translated with Babble Fish and the translation was corrected and reformatted by Colin Kaminski. *[http://www.designerinlight.com/lippmann/Sogokon_Lipp_phot_on_DCG.pdf Englsh Translation of Sogokon's paper about Lippmann photography and DCG.] Translated by Evgeniy Borozniak. '''Integral photography:''' *[http://www.designerinlight.com/lippmann/Lippmann_Epreuves_reversibles_Photographies_integrales_1908.pdf Lippmann, Epreuves réversibles. Photographies intégrales, CR 1908] - Reversible tests. Integral photographs *[http://www.designerinlight.com/lippmann/Interview_avec_Lippmann_La_photographie_en_relief_est_trouvee_Je_sais_tout_No_037_42_1908.pdf Interview avec Lippmann, La photographie en relief est trouvée, Je sais tout, No 037-42, 1908] - Interview with Lippmann, photography in relief is found, I know all '''Other papers by Lippmann:''' *[http://www.designerinlight.com/lippmann/Lippmann_Sur_la_mesure_absolue_du_temps_deduite_des_lois_de_l_attraction_universelle_1899.pdf Lippmann, Sur la mesure absolue du temps, déduite des lois de l'attraction universelle, CR 1899] - To the absolute measure of time, deduced from the laws of the gravitation *[http://www.designerinlight.com/lippmann/Lippmann_Franges_d_interference_produites_par_le_systeme_de_deux_miroirs_perpendiculaires_entre_eux_1905.pdf Lippmann, Franges d'interférence produites par le système de deux miroirs perpendiculaires entre eux, CR 1905] - Interference rings produced by the system of two perpendicular mirrors between them *[http://www.designerinlight.com/lippmann/Lippmann_Appareil_pour_enregistrer_lacceleration_absolue_des_mouvements_sismiques_1909.pdf Lippmann, Appareil pour enregistrer l'accéleration absolue des mouvements sismiques, CR 1909] - Apparatus to record the absolute acceleration of the seismic movements *[http://www.designerinlight.com/lippmann/Lippmann_Methode_pour_le_reglage_d_une_lunette_en_autocollimation_1914.pdf Lippmann, Méthode pour le réglage d'une lunette en autocollimation, CR 1914] - Method for the adjustment of glasses in autocollimation *[http://www.designerinlight.com/lippmann/Lippmann_Sur_une_methode_photographique_directe_pour_la_determination_des_differences_de_Longitudes_1914.pdf Lippmann, Sur une méthode photographique directe pour la détermination des différences de longitudes, CR 1914] - On a direct photographic method for the determination of the differences in longitudes The file http://www.designerinlight.com/lippmann/Lippmann_Des_divers_principes_sur_lesquels_on_peut_fonder_la_photographie_directe_des_couleurs_CR_1906_T actually consists of two different papers by Lippmann: Des divers principes sur lesquelles on peut fonder la photographie directe des couleurs, CR 1906. That paper has actually nothing to with Lippmann photography but is related to yet another system for the recording of color photos. It's extremely interesting and based on color coding through transmission gratings. Principally, I guess it's the thing Kaveh did. Remarques générales sur la photographie interférentielle des couleurs, CR 1906. adc7586a658d7ac97921a73f365907b059788cfd 0 420 991 990 2013-05-12T02:54:24Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:PeacockZsm.jpg]] Peacock Feather made Using the Lippmann Process at the Optical Structure Laboratory at the Rowland Institute at Harvard. Lippmann photography is a way of making a color photograph that relies on Bragg reflection planes in the emulsion to make the colors. It is similar to using the colors of soap bubbles to make an image. [http://chem.ch.huji.ac.il/~eugeniik/history/lippmann.html Gabriel Jonas Lippmann] won the Nobel Prize in physics in 1908 for the creation of the first color photographic process. A conceptual method would be to use a color holography film like Slavich PFG-03 and [[Index Matching|index match]] a first surface mirror to the emulsion side. (Lippmann used mercury for the mirror.) Expose the film with a pinhole camera. Remove the mirror. Develop the film to avoid shrinkage with something like [[Silver_Halide_Processing_Chemistries#JD-4|JD-4]]. When illuminated by a diffuse source a color photograph is visible. Lippmann is an excelent choice for making security documents as explained in this paper by Hanz Bjelkhagen on [[Lippmann Security]]. Viewing a Lippmann photograph, a regular photograph and a hologram are quite different. Here is a page on [[Viewing Lippmann Photographs]]. '''[[Lippmann Papers|Papers on Lippmann Photography.]]''' '''Links''' *[[Gabriel Lippmann|Gabriel Lippmann's Biography]] *[http://nobelprize.org/physics/articles/biedermann/ Lippmann Photography vs Holography] *[http://www.pinhole.cz/ Pin Hole Camera Theory and Design] *[http://www.designerinlight.com/lippmann/ Lippmann pdfs (mostly in French)] *[http://holographyforum.org/phpBB2/viewforum.php?f=14 Lippmann Forum] *[http://en.wikipedia.org/wiki/Bragg_diffraction Bragg Diffraction from Wikipedia] 6abf7f41bf6e657368b6b7da38e27ff3f19924f6 0 421 993 992 2013-05-12T02:54:24Z Jsfisher 1 1 revision wikitext text/x-wiki '''Optically Variable Device for Security Documents''' *Professor Hans I Bjelkhagen *Centre for Modern Optics *OpTIC Technium *St Asaph Business Park *ST ASAPH LL17 0JD, UK *hansholo at aol dot com ===INNOVATION=== The innovation is based on an old colour photographic technique, interferential photography or Lippmann photography, which was invented in 1891 by Gabriel Lippmann.[1] He was awarded the Nobel Physics Prize for his invention in 1908. Lippmann photography was the first technique, which could record colour photographs directly in the camera. However, the technique had several limitations, e.g., a special type of isochromatic film was needed, the image could not be copied, the image switched between a negative and a positive colour image depending on viewing direction. These limitations are now real advantages for a photographic document security device. A Lippmann photograph can be applied as a new type of Optically Variable Device (OVD) to be used on individually issued security documents, such as, e.g., identification cards, passports, credit cards, driving licences, and other documents where a high degree of security is needed. A Lippmann photograph is very similar to the embossed holograms currently used in this field; however, a unique recording of each document can be made to achieve a degree of security higher than that with mass-produced holograms. The recording of Lippmann photographs requires a special type of photosensitive recording material in contact with a reflecting layer. Modern panchromatic photopolymer materials or ultra-high-resolution silver halide emulsions can be used and, after being recorded and processed, laminated to security documents. A special type of recording equipment is required. Lippmann photographs are virtually impossible to copy and, certainly, cannot be copied by conventional photography or colour copying machines. ===Brief description of the recording technique=== A Lippmann photograph can be recorded on a photopolymer material in the following way. The photosensitive layer has to be rather thin, in the order of a few micrometers only. The light-sensitive layer must be coated on a flexible transparent base and a special type of reflecting foil has to be laminated on top of to the photosensitive polymer layer in perfect contact with it. Experimental photopolymer materials have been manufactured by DuPont, e.g., the HRF-700X071-3 film. This film was used to prove the concept of recording Lippmann photographs in modern photopolymer materials.[2] The polymer film laminated to the reflecting foil must be exposed in a special camera. After being exposed to the image-forming information in the camera, the reflecting foil is detached from the photopolymer film and the photopolymer layer is exposed to strong white light or UV light for developing. The image brightness is increased by heat treatment of the recorded film. The whole processing technique of the photopolymer film is a completely dry process, which makes it suitable for manufacturing a recording/processing machine intended for Lippmann security labels: Lippmann OVDs. After being processed, the transparent photopolymer label is laminated to its corresponding security document. The polymer film contains no dyes or any fading chemicals, which means that the archival stability is expected to be very high. The photograph is simply a piece of plastic material with the information recorded in it as an optical phase structure (refractive index variations within the photopolymer layer). In Fig. 1, a sample US passport is shown having a Lippmann OVD attached in the upper right corner. Figure 2a shows a close-up of the Lippmann OVD in colour, when observed perpendicular to the passport page. In Fig. 2b, the Lippmann OVD appears as a negative when viewed at an angle. [[Image:HBfig1.jpg]] Fig. 1. Passport with a Lippmann OVD. [[Image:HBfig2a.jpg]] Fig. 2a. Lippmann OVD in colour. [[Image:HBfib2b.jpg]] Fig 2b. Lippmann OVD as a negative. Note that these digital photographs cannot show the quality of the real Lippmann photograph with its extremely high image resolution. [[Image:HBfig3.jpg]] Fig 3. A passport with a Lippmann OVD attached in the upper left corner. Light from a diffuser above the passport makes it easy to inspect the Lippmann OVD on the passport. ===Advantages of the Lippmann OVD=== As already mentioned holograms are common in the field of document security, where mass-produced embossed holograms are attached to many types of security documents and most commonly recognised are the holograms on VISA and MasterCard credit cards. In almost every case where holograms are used, exactly the same hologram image is attached to a large quantity of security documents of the same type, e.g., the embossed dove hologram on the VISA cards. Since holograms are difficult to manufacture and lasers are required for the actual recording of a hologram, the use of holograms has been a valuable security device over many years. Nowadays, however, it is possible to copy holograms and there are examples of illegally copied security holograms reported. Nevertheless, a hologram is a very valuable OVD for mass-produced security instruments such as bank notes, cheques, vehicle stickers, product labels, etc. Lippmann photography offers a new type of optical security device that is unique and can be individually produced for each security document issued. Some of the advantages of a Lippmann OVD as a security device are: *Automatic recording and processing equipment for Lippmann OVDs can be manufactured to be used by security document producers and institutions issuing security documents. *The recording is rather simple to perform, no specially equipped laboratory is required. *The access to the recording photosensitive film, the special photopolymer material, can be strictly controlled by the manufacturer of the film. Only approved producers of security documents and institutions issuing such documents can order the material from the film manufacturer (e.g. like bank note paper). *The Lippmann OVD has a very high archival stability. *The Lippmann OVD is Bragg sensitive, which means it changes its colour depending on the angle of illumination and observation. It also switches between a positive and negative image. These features are extremely important as the effects are easily recognised when inspecting the Lippmann OVD. (Fig. 2 a and b) *The Lippmann OVD cannot be copied by conventional colour photography nor can it be copied using colour copy machines or colour scanners. *Since the resolution of the Lippmann OVD is extremely high, a reduced image of the security document can be laminated to the document, occupying only a limited area of it. In this case, magnifying techniques may be necessary to be able to read all the recorded information in the high-resolution Lippmann photograph. One example of a Lippmann OVD used for document security and counterfeit-resistant purpose is on a passport. The Lippmann OVD can be recorded of the passport page including specific information about the individual, the signature, and the conventional colour photograph of each issued passport. Then, a reduced-size Lippmann image is laminated to the page at an appropriate place. The colour shift of the Lippmann OVD indicates that it is a genuine Lippmann photograph and not a conventional photograph. In addition, all the information recorded in this OVD can be compared with the corresponding information in the document itself. It is a very difficult process to go through if someone wants to tamper with Lippmann-protected documents. The most important advantage is that there is really no point in trying to copy a Lippmann OVD since it is unique to a particular passport and of no use applied to a different passport. The authenticity of a Lippmann OVD is easy to verify simply by looking at it. However, it is also possible to make automatic inspection equipment that can check the iridescence of the image or compare the information recorded on the document itself with the corresponding information stored in the Lippmann OVD. The innovation (the application of Lippmann photography to security documents) is protected by a US patent and pending European patents.[3] The Lippmann OVD was first described in a paper published in Optical Engineering.[4] DuPont has expressed an interest in developing and manufacturing the special photopolymer film needed. Design and development of the recording and processing equipment are required. There is also more work needed to improve the quality of the recording material for Lippmann OVDs. There is a worldwide interest in increasing the security of documents in general. In England, OVDs have been introduced to protect banknotes. In this case a kinegram is used, which is similar to embossed holograms. Personalised documents, e.g., the UK passport, also carries an OVD. However, identical holograms are used on all passports. Credit cards, although they are also personalised documents, all carry identical holograms. Recently, Germany introduced a new type of passport which contains a monochrome, individually-made 2D hologram, overlaminated to the passport page. There is no doubt about the fact that personalised documents need to be more difficult to fake, which means, adding personalised security features to them. The worldwide market for document security is large and rapidly growing. The holographic security industry including the worldwide OVD market size in 2001 was $1.09 billion. There are many personalised documents which would benefit from a higher degree of security, for example, driving licences, traveling documents (Shengen Visa), corporate ID cards (air pilot's ID cards, people working in nuclear power stations), and military personnel, police officers, custom inspectors, etc., are all potential candidates for more secure ID documents. The approach as regards Lippmann OVDs as security devices is to introduce a complete recording/processing system which is used in house for the manufacturing of the labels. Currently, mass-produced embossed holograms and other types of OVDs (e.g. the kinegram) are produced by different holographic companies and then delivered to the issuers of security documents to be attached/laminated to various security documents. Since the Lippmann OVD is unique to a particular document, there is no need to produce them in advance. Therefore special recording/processing machines have to be made which can be sold or leased to companies or authorities issuing security documents. The machine is similar to a photocopier. The security document issuer records the Lippmann OVD at the same time the document is prepared. In this way the issuer has full control of the process and the security around it. ===REFERENCES=== # G. Lippmann, "La photographie des couleurs," C. R. Hebd. Séances Acad. Sci. 112, 274-275 (1891) # H. I. Bjelkhagen, "Lippmann photographs recorded in DuPont color photopolymer material," Proc. SPIE 3011, 358-366 (1997) # H. I. Bjelkhagen, "Secure photographic method and apparatus," US patent No. 5,972,546, Oct 26, 1999 # H. I. Bjelkhagen, "A new optical security device based on one-hundred-year-old photographic technique," Opt. Eng. 38, 55-61 (1999) 05bdb31738824daee6011edf37dfba801bb8b07e 0 423 997 996 2013-05-12T02:54:24Z Jsfisher 1 1 revision wikitext text/x-wiki == Lon Moore == Lon Moore was one of the first holographers to mass produce reflection holograms of popularized imagery. During the 1970s and 80s, he succeeded in experimenting with different processing techniques, controlling the available colors produced by the predominantly monochromatic medium and using his chemical palette appropriately in each of his holograms. Moore was a director and instructor of the San Francisco School of Holography and has exhibited his work at numerous venues in the US and Canada. 441554dfb57afedc7d68bcf72dce2d822333f6fe 0 424 999 998 2013-05-12T02:54:25Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Lcross.jpg]] ad8cf59eb04fa1975b0157f132d7cf769aa2afcf 0 425 1001 1000 2013-05-12T02:54:25Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Mackie line''' - an effect sometime found on a negative or print, in which a light line forms along the boundaries of the darkest image areas. It may also be caused during processing by the diffusion of exhausted developer, lack of agitation, or by solarization. *'''Macrophotography''' - photography which produces an image larger than the original subject size without the use of a microscope. *'''Magazine''' - a light-tight container holding roll film. *'''Magnification''' - the size of the image relative to the size of the subject used to produce it. It is an expression of the ratio of the subject-lens distance to the image-lens distance. When object distance = image distance, magnification = 1. *'''Mask''' - an opaque material used to cover the edges of the printing paper, and thus produce borders when the paper is exposed to light. *'''Masking''' - a system of controlling negative density ranges or color saturation through the use of unsharp masks. *'''Masking frame''' - an adjustable frame used to hold printing paper in position under the enlarger, also referred to as an enlarging easel. *'''Mastic varnish''' - varnish used for negatives. *'''Mat''' - an alternative term used for matte. Also describes the cardboard surround in a picture frame. *'''Matte field''' - a granular textured surface that disperses light in order to form a clear image. Used in the viewfinder optical system. *'''Matrix''' - a relief image, usually made from gelatin and used for processes such as dye transfer printing. Also a pretty good movie. *'''Matte''' - a term used to describe a non reflective, non-textured surface. *'''Matte box''' - a mask used to make images suitable for wide-screen projection. *'''Mercury vapor lamp''' - an artificial light source produced by passing current through mercury vapor in a tube. *'''Metal print''' - a photographic print made on a sensitized metal surface *'''Microfiche''' - a sheet of microfilm usually forming part of a filing system. *'''Microfilm''' - a film used to produce a microscopic record of a document and intended for projection. *'''Microflash''' - an electronic flash of very short duration used to illuminate subjects traveling at a very high rate of speed. *'''Micron''' (µ) - is one millionth of a meter. *'''Microphotograph''' - a photograph produced to a very small size which can be viewed with a microfilm reader. *'''Microprism collar''' - a grid type ring found in the center of a camera focusing screen, usually surrounding a split image screen. *'''Midtone''' - an area in a print or scene that contains average values. *'''Millimicron''' (mµ) - one thousandth part of a micron. (Also one nanometer) *'''Mired''' - an abbreviation for the term micro reciprocal degrees, a scale of measurement of color temperature. The mired value of a light source is calculated by dividing 1,000,000 by its color temperature in Kelvins. *'''Mirror lens''' - a lens system which uses mirrors within its internal construction. Most lenses of this type have a mixture of reflecting and refracting optics and are known as catadioptric lenses. *'''Microfiche''' - a sheet of microfilm usually forming part of a filing system. *'''Modeling light''' is a light used to create a three dimensional effect achieved through the perception of form and depth. *'''Modelscope''' - a device employing a short rigid endoscope fitted with a right angle mirror at its tip, used to photograph scale models from a seemingly eye-level viewpoint *'''Modular enlarger''' -an enlarger with interchangeable filtration heads and illuminations systems. *'''Monobath''' -a single solution which combines developer and fixer for processing b&w negatives. It is a quick simple system but does not allow for development control. *'''Monochromatic''' - light rays of a single wavelength. Monochrome is single colored. It is most frequently applied to black and white photographs, but can also describe sepia and other toned images. *'''Monopack''' - an outdated term describing a film carrying system. *'''Monorail camera''' - a sheet film camera, of modular construction, mounted on a rail system to give maximum camera movements. *'''Montage''' - a composite picture made from a number of photographs. *'''Mordant''' - a colorless dye absorbing substance used in some forms of toning. The silver image is converted into a mordant then soaked in dye. *'''Mosaic''' - a composite made up from a patchwork of partly overlapping photographs. *'''Motor drive''' - an automatic film wind-on mechanism which can be attached to some cameras. While the shutter remains depressed the film will keep winding on after exposure. *'''Mottle''' - a processing fault characterized by random print density differences. *'''Mount''' - a frame and/or backing used to support and protect prints and transparencies. *'''MTF''' (Modulation transfer function) - A comparison of contrast between a test chart and the reproduced image. One of the measurements of lens performance used in the manufacturing process. *'''Mercuric chloride''' - a chemical used in certain types of intensifiers. *'''Methyl alcohol''' - a volatile, poisonous spirit commonly known as wood alcohol. Used as a substitute for pure alcohol in some photographic processes. *'''Metolquinone''' - a combination of metol and hydroquinone, used as a developing agent (MQ developer). *'''Mordant''' - a colorless dye absorbing substance used in some forms of toning. The silver image is converted into a mordant then soaked in dye. *'''Multi-band photography''' - a method of aerial photography using cameras and scanners which are sensitive to different wavelengths in the spectrum to record different subject characteristics. *'''Multiple exposure''' - the technique of making more than one exposure on the same film frame, normally so that the images are superimposed. *'''Multiple flash''' - the use of more than one flash unit, usually operating simultaneously to light a subject. Can also be multiple modelocked lasers. *'''Munsell system''' - a method of precise color description, based on comparison with comprehensive hue and saturation charts. Has closest application to pigments, whereas the CIE system relates directly to light. 2dd0db6852e00fb5557ff51dc0afb40b6c6479c1 0 426 1003 1002 2013-05-12T02:54:25Z Jsfisher 1 1 revision wikitext text/x-wiki == A simple improvement for MBDCG == The original formula for MBDCG as invented by Jeff Blyth can be found on this page: [http://http://cabd0.tripod.com/holograms/id4.html] This procedure works really well, except that in cold environments often the Methylene blue crystallizes out before the holographic plate can be used. This is likely due to the fact that Methylene Blue (MB) will not stay in a solution with Potassium Chromate when the PH is below 8. In the original formula the PH is prevented from being too high by the addition of Acetic Acid. If the plate is left to dry in a cold environment, the Acetic Acid evaporates more slowly than the water in the plate and the PH drops below this value. A more stable plate can be made with the following procedure: ===STOCK SOLUTIONS for mixing:=== * TMG: 25ml TMG + 75ml DeIonized water (1,1,3,3-tetramethylguanidine). (Be careful because TMG is a very strong alkali. Use gloves, a protective breathing mask with Carbon Filter and eye protection. Or better, use a fume cupboard.) * Potassium Chromate: 4g in 100ml DeIonized water. * Methylene Blue: 4g in 1L DeIonized water. * Boric Acid: 100g crystals in a bottle. * Gelatin: Almost any gelatin with bloom strength of around 220 will do here. Best results are with Bovine Alkaline gelatin, but I have had good results with pig skin gelatin from the supermarket. ===HOW TO MIX THE STOCK MBDCG SOLUTION:=== # 100ml DeIonized water. Heated to 45C. # Add 12g gelatin. # Stir until all gelatin is dissolved completely. # Optionally, the solution can now be filtered through a fine coffee filter. # Add 0.77g of Boric Acid. Crystals until all are dissolved. # Now turn on your green safe light. Add 1ml of Potassium Chromate (4% solution) # Add 4.8ml of TMG (25% solution in DI water) # Check PH of the solution. If too high, add small amount of Boric Acid and check PH again. If too low, add a drop of TMG (25% in DI water) and check PH again. The optiumum PH is between 9 and 10. Use an electronic PH meter. They cost about 40 USD. # Add 6ml of MB (0.4% in DI water). ===A SIMPLE WAY TO COAT YOUR PLATES WITH AN EXTREMELY FLAT COATING IS AS FOLLOWS (MOLD COATING):=== # Clean two glass plates with normal dish washing detergent (for hand wash). # Clean both plates with Glassex (Windex in USA), or other Ammonia based window cleaner. # Treat one glass plate with Rain-X to make it water repellent. # Stick Scotch tape to two opposite sides on the other glass plate. # Heat both glass plates with a hair drier. # Put a small amount of stock MBDCG on the Rain-X treated glass plate and gently lower the other plate (the one with the Scotch Tape on the two edges) on top of it. # Allow this sandwich to rest for about two hours. # After two hours the plates can be separated by holding them vertically and gently wedging a sharp knife in between them. # If all went well, the glass plate that was not treated with Rain-X will now have a perfectly flat coating left on it. Leave this plate to dry for a few hours. After that it is ready to by cut to smaller pieces and to be used. ===OTHER WAYS TO COAT:=== * A Coating Rod can be used (Meyer Bar). This requires some practice. Both the plate and the coating rod need to be heated. It is essential that the coating rod is drawn over the plate at a very constant speed. * The Victorian Curtain methot. Hold a pre-heated and cleaned plate at an angle and pour the MBDCG solution along the edges and along the top. Steeper angles make thinner coatings. This method works well, but the top of the plate will have a thinner coating than the bottom. MBDCG is very sensitive to variations in thickness of the coatings. If this becomes a problem, try the above method (Mold Coating). ===HOW TO USE THE PLATES:=== The plates can be exposed just like any other holographic plate. They are somewhat less sensitive than silver halide plates though. They need about 30mJ per square centimeter. Thicker coatings are less sensitive due to the fact that they are less transparent. Perhaps using less MB in thick coatings will compensate for this. After holographic exposure, the following counter intuitive trick will greatly improve your hologram: during a period of one seventh of your exposure time, expose the plate in diffuse laser light (ie just wobble the plate in your expanded laser beam). This will greatly reduce noise in your hologram. Also, the hologram will be less sensitive to variations in processing temperature. ===Next, process as follows:=== # Leave the plate several minutes in a tray with water. Do this until all MB has dissolved out. The lights may be turned on now as the plate has lost it's sensitivity. It is a good idea to give the plate an additional rinse under cold running water now to ensure removal of the last traces of TMG from the emulsion as TMG can contaminate the subsequent alcohol baths and reduce their effectiveness. # Dip the plate in a tray with warm water, about 30 seconds. First try a temperature of 25C. More about this later. # Very quickly transfer the plate in a bath of 70% Isopropylalcohol and 30% water. Leave it in there about two minutes. This must be done in one smooth and fast movement because no water is allowed to dry or flow off the plate in between the water bath and the first alcohol bath. # Dip the plate in a bath of 100% Isopropylalcohol. (about two minutes) # Dip the plate in a second bath of 100% Isopropylalcohol. (about two minutes) # Put the plate on a dry towel (emulsion up), and dry it with a hair dryer set to HOT. If all went well, you will see an image slowly appear. If you see some crystalline structures appear on the plate, continue to blow dry. They will disappear again. (This is an indication that the optimum temperature for step 2 has been reached.) # If the hologram looks blue or dark green and is very dim, it can be re-processed. Starting at step 2. But this time at a slightly higher temperature. The hologram will come out brighter this time. At a certain temperature, the hologram will finish at a very pretty golden colour. It will be broadband now and not have so much depth. If processed at a higher temperature than the one that results in the golden colour, the hologram will be noisy and milky. Low temperatures in step 2 make very sharp narrow band holograms. Higher temperatures make less sharp broad-band holograms. ===Cristiano posted this recipie=== Hi, MBDCG is a tricky job. In my experience many variables should be tuned in order to get good repeatable results. For example, gelatine strength has a great impact on the warm water bath temperature. Coating drying time, as well as room RH, influences sensitivity. MB concentration, coating thikness, gelatine/TMG ratio, IPA baths temperature and so on make the situation more complex. Speaking about MB concentration, more MB dissolved in the emulsion makes the emulsion more sensitive but, as MB adsorbs red laser light a Denisyuk hologram will result dim. There are infinite scenarios. Here is my definitive MBDCG formulation *Pig gelatine 280 Bloom 10 g *Potassium chromate 1 ml (5% water sln) *TMGA 6 ml (25% water sln) *TMG 1.5 ml (25% water sln) *Methylene blue 2.5 ml (0.4% water sln) *Water 80 ml Adjust pH to 9.3 with 25% TMG sln Emulsion preparation * swell 10 g of gelatine in 80ml if cold water * heat to 40-45C to dissolve gelatine -never exceed 45C otherwise gelatine strength migth be altered- Stirring continuosly @40C: * slowly add 6ml of 25% TMGA (~ 1ml/sec) * add 1.5ml 25% TMG very slowly (~0.1ml/sec) constantly checking the pH that never should rise above 9.5. Correct the pH with 10% acetic acid. * slowly add 1ml of 5% Potassium chromate solution (~ 1ml/sec) * slowly add 2.5ml of 0.4% Methylene blue solution (~ 1ml/sec) * stirr for 3-5 minutes the whole mixing process should require about 10 minutes. Coating * Mold coating technique using 80um spacers (3.1mils) * 6 hours @ 28C gelling time * before detaching the glass sandwich chill it for 1 hour @5C (this step helps to get a defects free coating) * dry in steady environment (air stream free) for 12hrs @28-30C 60-70% RH. Drying temperature and RH seems to have great influence on coating characteristics. Exposure * Once the holographic setup is ready, wait for about 30 minute to allow all components to stabilize * Expose for 20minutes with a power density of 20uW/cm^2 for a 200x200mm plate. NOTE: I'm using a 20mW He-Ne laser (JDS 1145-P) warmed for 3 hours. Development and finishing * After exposure wait for 15 minutes * Wash in cold water (10C) for 5 minutes * Gently immerge the plate in water @ 19 to 25C (this step must be accurately tuned in according to your gelatine characteristics) for 30 seconds * Dry in 95% IPA @ 20-25 degrees for 1 minute * Dry in 97% IPA @ 20-25 degrees for 1 minute * Dry in 99-100% IPA @ 20-25 degrees for 5 minutes * Force quick IPA evaporation with hairdrier * Finish the hologram in pre-heated oven @125C for 10minutes I hope this helps you. Cristiano ===THINGS THAT CAN GO WRONG:=== * Be careful with chemicals and read the relevant MSDS (Material Safety Data Sheets) each time before using. * If there are random variations in brightness across the processed plate, it has not stabilized to the ambient humidity yet, or it has not dried long enough. Drying can be accellerated with a hair drier set to cool. This can cause some dust to adhere to the plate though. * If the gelatin detaches from the glass plate during processing (usually happens during the washing bath in step 1), don't be tempted to take it out of this bath before all the MB has washed out. Putting a plate in Isopropylalcohol that is not clean, will contaminate this bath and make it useless. If you only use clean plates in the alcohol baths, these baths can be used many times. Detachment can be prevented with an extra pre-processing step during the cleaning of the glass plate as follows: Make the following mix: 40ml 3-amino-propyltriethoxysilane + 45ml IsopropylAlcohol + 5ml DeIonized water. After 24 hours, take 1ml of this stock solution and add 20ml IsopropylAlcohol. Rub a cleaned glass plate with this solution. A white haze will appear across the glass. Leave the plate for about two hours and clean again with Glassex (Windex in USA). The glass is now sticky to gelatin forever. Gelatin will not detach anymore from this glass. Mark the glass with a small dot of a black waterproof CD marker so you can tell the difference between a silanated glass and a Rain-X treated glass. * Plate is insensitive/very dark blue before exposure and takes more than 5 minutes to become transparent in the washing bath. This happens when the coating is too thick. Try a lower concentration of gelatin or less Methylene Blue in the stock solution. * There is foam on the gelatin solution before coating it on the glass. This results in ugly tiny air bubbles in the coating. Allow the MBDCG stock solution to cool and gell before using. When it has gelled, the bubbles are on top of the gelatin. They can now be cut out with a small plastic spoon. * Random colorations appear across the plate. This happens when you don't transfer the plate from the warm water bath quickly enough into the first alcohol bath. Try to cover the gelatin side with a cover glass or plastic sheet (while in the warm water bath) before moving it into the alcohol bath. Once fully submerged in the alcohol bath, remove the cover. * Random spots of Pretty Golden Area's appear across the plate (usually at the sides of the plate): Hah, you have found the threshold temperature in your warm water bath, above which the hologram becomes a golden colour. Re-process with the warm water bath one degree Celsius higher. ===USEFUL TIPS:=== * A great way to measure small amounts of liquids is to use a 10ml syringe. Use the type with rubber seals because they operate more smoothly. * A great way to measure small amounts of solids is to use a digital scale used to measure the weight of letters. Make sure that they have a resolution of one gram or less. * Stock solution stays usable a very long time. Do not allow it to freeze though. I haev re-used stock MBDCG six months after first mixing it. * Plates stay usable a very long time. I have exposed a plate that was two weeks old with no difference in sensitivity. * Unlike silver halide plates, MBDCG plates are very resistant against accidental exposure to light. In fact, I keep my ready-made plates in my house. Before exposure I quickly walk with them in broad-daylight to my garage and use them. Use a green light as a safe light. Don't worry if there is a small amount of red left in your safe light. MBDCG is not sensitive enough to be problematic with small amounts of red light. You can check the spectrum of your safe light by looking at it's reflection in a dvd. If you see only green, perfect!!! If you see some red, no big deal for MBDCG. * Unlike silver halide plates, MBDCG plates are very VERY SUPER resistant against accidental exposure to light. I think this is because of non-linear behaviour of the plates. I once tried to expose a plate that had been in my house uncovered for two days. Sure enough, a dim hologram could be made with it. :) * Don't be satisfied with a dim hologram. MBDCG holograms can be very bright. So bright in fact that you don't have to paint them black on the back side. You will not be able to see through a good MBDCG hologram when it is properly illuminated. * MBDCG holograms are somewhat sensitive to moisture. If you want to keep your hologram in good condition a long time, it has to be covered with a protective glass plate and sealed on the sides. If you don't do this, the plate will fade over time. The good news is though that you can re-process the plate. It will look as pretty again as when you processed it the first time. * Stock MBDCG solutions last virutally forever. You need about 2 ml to cover a 10x15cm plate. So you can make about 50 plates from 100ml of stock. You can make about a liter of stock MBDCG from the pre-mixing solutions above. * A 10x15cm plate needs about 3 minutes of exposure time at 50mW. And about 25 seconds of diffuse post exposure to harden the plate. * If you are in a real big hurry to mix MBDCG stock and don't worry about small lumps in the solution, the following procedure works well (I have never seen the small lumps, but some people have had them with certain types of gelatin): -100ml DeIonized Water -4.8ml TMG -Add small amounts of Boric Acid crystals until the PH drops to about 10. (about 0.77 gram total). -1ml Potassium Chromate (4%solution in DI water) -6ml Methylene Blue (Diluted to 0.4% in DI water) -Add 10g gelatin. -Check PH again. This has the added advantage that the gelatin dissolves much faster due to the higher PH and no air bubbles form in the solution. * If you store your plates in another location than the one where you expose them, they need some time to adjust to the temperature and humidity of the location where you expose. A quick way to adjust the plate is to blow it with a hair drier set to COLD for a few minutes. * You don't need a magnetic stirrer to mix MBDCG. Simply use a cheap hot plate. Put a pan with sufficient water on the hot plate and set the plate to a temperature of about 40C. Then place the glass container in which you mix the chemicals in the pan. The water in the pan now functions as a temperature buffer and will react more slowly to too high or too low settings of the hot plate. This also has the added benefit that PH meter and plastic spoons can be cleaned in the water that is in the pan. Don't allow the temperature to go over 50C. * Use plastic trowaway spoons for mixing and measuring chemicals. That way you (or your better half) will never make the mistake of putting them in the dishwasher or with the spoons that you use for eating. * Clearly mark all glassware and pots and pans that you use for MBDCG with a scary looking skull and write poisonous on them. Then store them in a place where children cannot touch. * Instruct family that ARE qualified and able to be close to the chemicals and equipment: If anything falls over or is noticed to be leaking..... WALK AWAY AND CLOSE THE DOOR!!! Then tell you what happened. ====Tips from Cristiano Perrucci:==== I would like to emphasize this method requires a few little adjustements: * MB concentration SHOULD be tuned for optimum results depending of gelatine hardness and tape you are using (mine is 3.1 mils) * Gelatine concentration MUST be tuned for differents kinds of gelatine and TMG concentration. * During gelatine pouring, glass plates SHOULD be controlled for better results, and kept closely to emulsion temp. * Traces of water repellent (I'm using Rain Clear as Rain X is unknown here in Italy) on glass surface helps to get a really smooth coating. ====SO-DCG for Green Lasers==== You can substitute MB with Safranine "O" and shoot with a 532nm laser and keep everything including concentrations just the same as with MBDCG). Safranine "O" is fully compatible with MB so you can do 2 colour ones. Exposures are the same as G307, however G307 can not be made panchromatic. aceb0d53c8116b86f7bb108e8651ba17e9741010 0 427 1005 1004 2013-05-12T02:54:26Z Jsfisher 1 1 revision wikitext text/x-wiki MOPA lasers are pulsed lasers with very high power outputs. This discussion is limited to lasers for holography. MOPA stands for Master Oscillator with a Power Amplifier. The master oscillator power is independent of the final output power allowing for it to be designed with a [[Laser#Longitudinal_Modes_and_Coherence_Length|Single Longitudinal Mode]]. After the Master Oscillator there is a Power Amplifier consisting of at least one stage but usually many stages. <font color="red">'''Warning:'''</font>MOPA lasers are often Class IV LASERS! Do not undertake the design and construction of one until you understand the electrical and electromagnetic safety issues! See [[Laser Safety]] for some introductory concepts. ==Master Oscillator Design== The master oscillator, as a minimum, consists of a lasing medium, a Q-switch, a highly reflecting mirror (HR mirror) and an output coupler (OC mirror). A master oscillator for holography will also have a polarizing element, [[Etalon]]s, resonant reflectors and an aperture. The design of the Master Oscillator is of primary importance as is defines the limit of the properties of the final output beam. For holography we want the Master Oscillator to have Single Longitudinal Mode and TEM00 temporal mode. We want a short pulse but if it is two short it will limit our coherence length. In considering different resonator designs it is useful to make a spread sheet of the different parameters. Ron Michael has created a remarkable one. [http://www.rotorwave.com/weights.xls MOPA Spread Sheet]. Insert equations to calculate limiting coherence length and maximium movement for a given pulse width. ===Resonator Configurations=== Deisgning the resonator configuration controls a great deal of the parameters of the laser system. Not the least important of which is the reliability of the alignment. Since holographers are unlikely to have an unlimited budget the resonator design will become a compromise between available surplus parts and a stable design. Important paramters controlled by the resonator: *TEM mode (Spatial Mode) *Coherence Length (Logitudinal Mode) *Input power to the Amplifier section *Alignment stability It is important to remember that a solid laser rod acts as a negative lens during the intial flashlamp pulse due to thermal expansion where the outer radius absorbs more light intially. After repeated firings (faster than the thermal relaxation time) the outer radius of the rod will begin to cool faster than the center and therefore develop a positive thermal lensing effect. Some rods like ruby also will under go index of refraction changes due to inversion levels and therefore also have a lensing effect due to pump non-uniformity. In ruby dual flashlamp arrangements for example this effect can produce greater divergence in the flashlamp axis. ====Plano-Plano==== [[SSY-1]] ====Plano-Concave ==== This is a popular way of enhancing spatial mode discrimation by the use of two spherical mirror configurations or 1/2 of that which is a plano concave arrangement. TEM mode discrimation is greatest for the confocal arrangement and least for the plano/plano arrangement. The Plano Concave is a good intermediate with typical g values of 0.8 to 0.9. g=1-L/R where L is resonator length and R is mirror radius. Typically the aperture is inserted next to the HR mirror radius and the plano OC can be etalons etc for longitudinal mode control. ====Plano-Convex ==== This is an example of a un-stable design. ====Convex-Convex==== ====Resonant Reflectors==== When an [[Etalon]] is used as an output coupler in a resonator configuraton, then it is generally called a resonant reflector due to the [[Etalon]]/multiple reflections that produce resonance with some modes enhanced and others diminished based on the [[Etalon]] thickness and index of refraction both of which can be controlled by temperature tuning. These RR are uncoated because of the high internal power density within the resonator due to the Fabry Perot reflections. Most RR are either single plate or multiple plate with air spacing to provide mode discrimination within the gain profile of the laser. Thin plates provide wide peak separations and wide separations provides thin peaks. ===Aperture=== Inserting a aperture into the Oscillator cavity will prefer TEM00 mode by a process of depleting higher modes through preferential Fresnel Diffraction of the higher modes since higher order spatial modes also take up larger spatial cross-section. ===Lasing Medium=== The active material for the lasing medium needs to be carefully chosen for narrow line width, high gain and a useful transition frequency. The most common lines used are summarized below: *1064nm [[Nd:YAG]] - Frequency doubled to 532nm *694nm [[Ruby]] *946nm [[Nd:YAG]] - Frequency doubled to 473nm The ends of the laser rod can be finnished in a number of ways. They can have [[Brewster's Angle]]d ends which polarizes the beam. They can have AR coated ends or if the ends are ground perfectly parallel, the rod itself can be an additional resonator in the cavity helping to creat a Single Longitudinal Mode. *Note: [[Nd:Glass]] has very interesting properties but the broad wavelength and low gain make holographic resonator use difficult. It is an interesting choice for an amplifier however. The medium's stimulated emission cross section Definition: [http://www.rp-photonics.com/cross_sections.html from Encylopedia of Lasers] Some emission cross-sections: Group A *Ruby 2.5E-20 cm^2 *Q-246Nd:silicate 2.9E-20 cm^2 *Yb:YAG 2.1E-20 cm^2 *Alexandrite 1.0E-20 cm^2 Group B *Nd:YAG 65E-20 cm^2 1.06414 R2->Y3 transition *Nd:YLF 18E-20 cm^2 *Nd:YV04 25E-20 cm^2 *Ti:Sapphire 41E-20 cm^2 Above was grouped into two catagories. Group A with smaller cross-sections are able to store more extractable energy due to lower gain allowing a higher population inversion (more pumping) before onset of ASE depopulation and spontanteous emission (lifetime)losses. These are best for q switch operation yielding higher output. Group B with larger cross-sections offer higher gains and are best used in CW or Quasi-CW operations yielding more efficiency and higher average power outputs in these modes. Of course q switch operation can be achieved in either group with passive q switching more dependent on smaller cross-sections for higher output than active q switches. Once gain reaches the physical conditions ripe for ASE, the depopulation increases and the gain levels off. Gain can be modulated by temperature for example, cooling ruby and heating nd:yag will allow more output extraction. Absorption cross sections, absorption spectral range, and spontaneous fluorescence lifetimes are good indicators for pump rates (pulsed etc) and absorption overlaps with regard to efficient pumping and eventual laser gain. ===Flash Lamps=== It is the goal of a flash lamp to provide energy at the absorption bands of the active material. For [[Nd:YAG]] the important bands are 730nm to 760nm and 790nm to 820nm. (Note: There is a strong peak at 808nm making 808nm laser diodes extremely efficient as pump sources.) For [[Ruby]] the desired pump regions are 370nm to 420nm and 520nm to 690nm. Since the cost the the active medium is an order of magnitude higher than the flash lamp the frugal holographer will pick the active material first. Once the laser rod has been selected the length of the flash lamp should approximately match the laser rod and the flash lamp bore diameter should approximately match the laser rod for good efficiency. Flash Lamps are defined by a few simple parameters. *Bore ID *Flash Length *Gas Fill (Argon or Krypton) *Fill Pressure (linears 400 to 2000 Torr. Helicals are typically 300 Torr for easy firing due to longer arc lengths.) One you know these 4 parameters the electrical behavior for a flash lamp is defined. Additional parameters defining the pump efficiency are the media in between the flash lamp and the active medium. Different envelopes with different properties have been developed. Also any cooling medium will also effect the pump radiation. (Envelopes and cooling materials have been designed to adsorb unwanted frequencies and to transmit desired frequencies.) Krypton lamps are preferred for [[Nd:YAG]] for low pump energies and Xenon is preferred for higher pump energies. (Above 2x10^5 W/cm^3) Generally surplus lamps found with an electrode that is a sharp point(cathode) are typical CW arc lamps like Krypton and have very thin 0.5mm walls to help in thermal conduction. These lamps will easily explode if you try and use them as flashlamps. Xenon/Krypton flashlamps generally have 1mm or better fused quartz walls and have rounded or blunt style electrodes. Both Xenon and Krypton lamps can be made into arc lamps for C/W use or the pulse style and the electrode design generally gives away the designed use but not the gas used or it's Torr/Atm fill pressure. The energy that makes a flash lamp explode is known as the explosion energy. It is important to operate at a fraction of this energy to increase lamp life. At 60% of the explosion energy the lamp will fail in about 10^2 pulses. Additionally based on cavity use etc it best to derate the lamp since some energy is re-absorbed by the cavity etc. Most load calculations are done for free air thermal conduction etc. ====Electronics==== Ohm's Law is V=IR. Voltage equals current times resistance. Voltage control allows charging control of the storage capacitors and therefore vary the amount of pump energy desired. Two typical methods are: *Variac control - Main power transformer is capable with rectifying circuits of fully charging the storage capacitors. The variac autotransformer allows control and varies the input voltage to the main power transformer. *Solid state relay control - Here the SSR can cutoff the charging once a pre-determined voltage is reached. SSR are placed on the input primary of the main power transformer.SSR leak current and therefore some charging is un-avoidable in this design. Danger exists unless extra steps are taken to ensure capacitors are not charged. All parts of the circuit must be able to handle current requirements and circuit breakers should be used to protect device and personnel. Proper grounding of the equipment chassis, laser head, and parts should be in place. Personnel should be kept away from all circuits by the use of the double protection of insulations and the use of chassis enclosures as a secondary isolation technique. See other safety requirements concerning procedures and testing for electrical device safety standards. Additionally for operators and the use of interlocks, warning labels, etc, and the need for a designated LSO:Laser safety officer in the use of lasers. =====Capacitors===== Oil caps designed for pulse use and some SCR communtation types with high Dv/Dt allow use in pulse storage applications. Oil capacitors that have lost more than 10 percent of it's rated capacitance value should not be used. Lifetime is limited due to stress near full voltage rating. Electrolytic caps have higher energy density than others and allow for compact designs but due to electrolyte heating and drying, they are more prone to failures. This rating is also found in it's temperature ratings and it's ripple current ratings. And generally using the highest ripple rated caps in parallel to increase the overall ripple current rating helps in reducing the charging/discharging heat and prolonging the capacitor's life. Additionally low ESR values aid in lower internal heating. If caps are also added in series, the fewer number of series caps the better and they must be equalized with enough current flow from a voltage divider.4 caps in series should be about the reasonable maximum. Also care should be taken to avoid shorting through their common exterior metal cans if clamped and are used in series. Best to have them insluated mounted. Gas/liquid venting is possible and best used in proper orientation Used caps should be avoided since shelf life and ripple use may be unknown with regard to electrolyte drying. Best to use new recent manufactured capacitors with known specification. All caps have the ability to explode and housings should be used. Additional fire protection and extinguishing should be available. =====Resistors===== Resistors have voltage ratings that should not be ignored when used in HV circuits and across capacitors for discharging or voltage equalization. HVX, HVW resistors can have high ratings for voltage and some of the specialty resistors power resistors can have 64kv ratings, but typical wire-wound 225watt power resistors may be limited to 4kv or less and common 1/4 watt carbon comp generally are around 250v rated. Verfiy with mfg ratings before using. One reference: [http://www.ohmite.com/cgi-bin/products.cgi] =====Trigger Coils circuits===== Series injection is having a low inductance secondary coil of the transformer in series with the flashlamp. External trigger is using a typical high inductance secondary coil's one lead wrapped around the flashlamp and the flashlamp and other coil lead referenced to ground. Trigger coils are pulse transformers and made of ferrite RF materials which has a fast response and low staturation inductance level. Additionally potted to prevent arc-overs on coil windings. Since the main storage capacitor goes through in series injection type pulse transformers, the max peak current ratings of the transformer should be observed or destruction of the pulse transformer with a loud bang and flying potting material can be injurious ===Cavity Design=== The cavity must be designed to reflect the light from the flash lamp to the active material (laser rod). The more evenly the active material is illuminated the better the beam profile will be. Since holography requires a very clean Gaussian beam careful attention needs to be paid to the cavity design. Cavities can either be highly reflecting or diffuse reflecting. Highly reflecting designs are preferred. If only one linear flash lamp is being used for the master oscillator then the cavity design should be elliptical with the lamp and the rod at the foci of the ellipse. It can be shown that the efficiency is increased by making the ratio of the major axis to the minor axis as small as possible. Just enough room for the mounting and electrical connections is used. The cavity can be made from any heat resistant material. Aluminum, copper and stainless steel are used. Highly polished aluminum can provide a sufficiently reflecting surface for a Ruby laser but aluminum is not as efficient as a silver plated cavity for [[Nd:YAG]]. Cavities can be polished metals but better is to coat soft metals with nickle and polish it then deposit silver or gold. In the case of silver it must be coated with an overlayer to protect the silver from the atmosphere. SiO is usedfor telescopes and works wll for cavities. It is important that the reflective frequencies match the absorbtion frequencies of the active material. An overview of reflectivity: *Evaporated Al is about 90% reflective from 200nm to 1000nm. *Polished Al is about 10% less reflective in the UV and about 3% less reflective in the near IR. *Silver reflectivity starts at about 350nm and reaches a high reflectivity at 420nm. Evaporated is about 5% better. *Golds reflectivity starts at 500nm reaching full reflectivity at 620nm. *From 500nm to 800nm evaporated gold is much more reflective than polished gold. [[Making a Homebuilt Pump Cavity]] ===Polarizing Elements=== Any element that tends to polarize the beam inside the master oscillator cavity will help to ensure that all of the cavity's energy will go to that polarization. This can be [[Brewster's Angle]] rod ends on the active medium. Placing a window at [[Brewster's Angle]]. Or placing one of the optical elements at [[Brewster's Angle]]. IE. the Q-Switch. ===Q-Switching=== A Q-Switch keeps the lasing medium from lasing until it is at a population inversion by blocking one of the mirrors. The Q-Switch design sets the pulse width. Q-switches can either be passive or active. ====Passive Q-Switch==== Passive Q-Switches work by using a saturable dye. Until there is enough light to bleach the dye it remains opaque. This allows the flash lamp to store energy in the laser rod until the stored energy reaches a threshold. A passive Q-Switch represents a large insertion loss (Even when bleached clear it still adsorbs a significant portion of the light). If the laser starts to lase in TEM00 mode it will tend to bleach out the center of the Q-Switch first. This tends to reinforce the TEM00 mode. [[Cr4:YAG]] is the most common Passive Q-Switch used. ====Active Q-Switches==== There have been many active Q-Switch designs. Since we are only looking for a single pulse in holography they benefits are usually not worth the extra cost. Because they are complicated and expensive we will just list the types. *Rotating Prism *Translational Optic *Rotating Disk with a hole *Electo-optic *Pockels Cell *Kerr Cell *Acousto-optic ===Output Couplers=== The simplest output coupler is a partially reflecting mirror. The optimum reflectivity can be calculated. A mirror can be designed with any figure or reflectivity profile. A mirror design with a radial reflectivity can help to insure TEM00 mode. A resonant reflector is made with two or more parallel plates. It only allows a flat configuration but often the additional mode selectivity is desirable. ===Factors Effecting Spatial Mode=== High diffraction losses caused by a aperture and small volume of the gain medium have caused researchers to look for other alternatives to allow spatial mode control without the small mode volume of a typical stable resonator with just an aperture for mode control. ==== Cat's eye Resonator ==== Published in "Proceedings of the IEEE" Apr 1965 and again in April 1972 both papers by P. W. Smith indicated the use of a cat's eye resonator which is two flat mirrors with a convex lens whose focal length is 1/2 the distance between the mirrors and is placed at the half way point with an aperture at one mirror and the laser medium at the other mirror. As you close the aperture at one mirror, it forces the mode volume to become larger through the laser medium. This arrangement basically forms a confocal resonator (actually 1/2 of one) with large mode volume in the medium. According to Li and Smith they reported 2.5 times the output power than just from an aperture alone. Back in 1965 this was done with a He-Ne laser. Of course you must consider the thermal lensing that can happen from a solid rod. During Q-switch operation this lens can be negative during this initial pumping. Depending on pump levels this lensing can become pronounced. So the use of telescopes or convex lenses must be calculated with the lensing of the rod. To approximate the lens value pass a He-Ne beam down your amplifier rod and measure the beam spread before and after pumping to calculate your negative lensing at the power levels you want to use before designing the resonator and optical elements. ====Telescopic Mode Control==== Since the diffraction losses required for a TEM00 beam require a small aperture, inventive laser designers have sought methods to increase the utilization of the active material. One way to do this is to place a telescope into the resonator. The proper choice of lenses and spacing allows one to compensate for the thermal induced lensing of the [[Nd:YAG]] rod. [[Image:YAGTelescope.jpg]] ===Factors Effecting Longitudinal Mode=== The only way to ensure that successive shots are the exact same frequency is to temperature control the YAG and any resonant reflectors as well as any etalons. This is not a problem unless you are using multiple flashes for holographic measurements like double exposure holographic interferometry. ==Power Amplifier Design== [[Making a Homebuilt Pump Cavity]] ===General Considerations on Setup Configurations=== * Amplifier isolation between stages either by using spatial filters or wide separations and tilting the rod relative to each other help reduce feedback that leads to parasitic oscillation due to ASE. * Isolators consisting of Faraday Rotators and waveplates can also be used to provide the best isolation but are quite expensive. * Amplifier rods also can have face tilts of the arctan(Rod_diameter/Rod_length) as a minimum recommended tilt to reduce this problem. * Additionally consideration should be given to ground rough barrels on the rod and possible water cooling to help reduce TIR (Total Internal Reflection) both which help reduce the parasitic oscillations that can occur in ring modes around the circumference of the rod. === Single Pass Configurations=== ===Multiple Pass Configurations=== ==Frequency Doubling== There are many crystals that exhibit non-linear properties and can be used for frequency doubling. The most common doubling scheme for holographers is 1064nm to 532nm. *[[KTP]] *[[KD*P]] *[[LBO]] The choice of crystal has to do with damage thresholds, conversion efficiency and cost. The correct choice changes with each new price quote. :-) ==Filtering Out Un-Wanted Frequencies== Since the frequency doubling efficiency is not 100%, there is always some of the original laser frequency in the output. This is customarily divided off in order to get accurate power readings and to keep from fogging the film. ===Absorption Filters=== For small frequency doubled lasers absorption filters can be employed that absorb 1064nm and transmit 532nm. The have very low damage thresholds and are not recommended for pulse lasers. ===Dichroic Mirrors=== A mirror coated to reflect 532nm at 45 degrees and coated to transmit 1064 is another way to separate the unconverted light from a frequency doubled system. Note: It is equivalent to reflect 1064nm and transmit 532nm. It is very important to dump the un-wanted energy into a beam ump as it can be quite dangerous. During alignment of the frequency doubling crystal it can represent more than 90% of the energy! ==Safety== Pulsed lasers are not to be trifled with! The beam can not only do damage to eyes and skin but can burn holes and start fires! Make sure to send all beams to a [[Equipment#Beams_Dumps|Beam Dump]]. The amount of energy stored in the power supply can kill. The voltages involved can jump large gaps. The capacitors can hold energy even when the power supply is unplugged. Never operate a laser with the cover removed. The cover is an important piece of safety equipment to protect from stray light and from high voltage. Power supplies should be designed to bleed off capacitors when unused. See the HoloWiki's [[Laser Safety]] for more information and [http://www.repairfaq.org/sam/lasersaf.htm#saftoc Laser Sam's Safety Section.] ===Stories of Failed Safety Programs=== but hopefully will serve as a reminder... surplus: *http://www.rli.com/resources/accidentdetail.asp?ID=393 Death by HV: *http://www.rli.com/resources/accidentdetail.asp?ID=47 *http://www.rli.com/resources/accidentdetail.asp?ID=73 Lucky with HV: *http://www.rli.com/resources/accidentdetail.asp?ID=184 *http://www.rli.com/resources/accidentdetail.asp?ID=219 *http://www.rli.com/resources/accidentdetail.asp?ID=345 But I had eyewear: *http://www.rli.com/resources/accidentdetail.asp?ID=165 oops: *http://www.rli.com/resources/accidentdetail.asp?ID=168 *http://www.rli.com/resources/accidentdetail.asp?ID=180 It also happens to companies: *http://www.rli.com/resources/accidentdetail.asp?ID=288 ==Further Reading== *[http://www.repairfaq.org/sam/laserstr.htm Solid State Laser Testing from SAM's Laser FAQ] *[http://holographyforum.org/pulse/technical.htm Ron Michael's Archive] *Solid-State Laser Engineering by W. Koechner ISBN 3-540-65064-4 *[http://www.rp-photonics.com/q_switches.html Q-Switches] ==Supliers== ===New=== *[http://www.kenteklaserstore.com/laser-components_33.aspx Kentx Laser Parts and Fabrication] *[http://www.casix.com/ Casix] New Crystals ===Surplus=== *[http://www.mi-lasers.com/ Mi Lasers] *[http://www.surplusshed.com/ Surplus Shed] *[http://www.sro-optics.com/ Sterling Resale Optics] 08b7a72b712702f6c2aab749e3a8316113cb2644 0 428 1007 1006 2013-05-12T02:54:26Z Jsfisher 1 1 revision wikitext text/x-wiki ====A Machined Film Holder==== [[Image:FilmHolder.gif]] by: Colin Kaminski '''4" x 5" Film Holder''' after Dinish and Joy Padyir's. This film holder is a copy of one Dinesh and Joy were using when I was there. I made it from 3/4" square aluminum bar. (This is not quite how I made it but I am going to include how I would make it again when I make a second one this week.) Take a 12" or so section of 3/4" aluminum bar and set a table saw to cut .25" deep. Set the fence .125" from the blade (make sure the fence is parallel to the blade!) Run the piece of aluminum through. (Use two push sticks so you don't get your hands anywhere near the blade. Also a feather board or two would be of use but I did not have any handy.) Then move the fence over about .035 inches or however wide you want the slot. You can make the slot wide enough to accommodate 2 plates and film if you wish. Then hack saw it to 4.25" or so. (Where the table saw blade exited the part you will notice the slot is wider than the rest of the part. This is because the blade started to ring upon exit and you should make sure to cut off this end.) Set up your cross cut saw on your table saw very square then taking about .030 inches in a pass trim both ends until the ends are clean, square and the piece is exactly 4". Cut another piece to 6+ inches and clean up the ends on the table saw till it is square and 6" long. Measure down the 4" pieces 1" from each end and make a line. Measure from the lip .125" and make a line. Where these lines intersect, use a drill press and drill a #36 hole through to the channel. (Marking the hole with a spotting dril is handy to keep the wholde from drifting. At least make sure you have as little of the drill bit sticking out of the chuck as posible and mark the spot with a punch.) Tap to #6 32 tpi. These will be the plate holder screws. (Note: tap from the small side for a reflection plate holder and from the thick side for a transmission holder, or you can make two slots in the same plate holder.) Mark the two 4" pieces on the ends in the center. (This operation will make the parts "Handed" so make sure to pick opposite ends for this mark.) Drill in a drill press a #F hole about 1/2" deep. Tap to 5/6" 18 tpi. Measure .375" up and over on the 6" pieces (on the 6" face) and make a mark at each end. Drill through with a 5/16" drill bit. (If you miss this hole or the holes in the ends you can make this hole larger so you can get the parts to align.) In the center of the bottom of the 4" pieces (away from the slots) drill a #7 hole .425" deep. Tap with a 1/4 20 tpi tap. In the center of the 6" piece, on the same face as the holes, drill a #7 hole .425 or so deep and tap to 1/4" 20 tpi. These will be the mounting holes. Clean up the corners with a file, and clean up the holes with a countersink tool. Spray paint with Krylon Ultra flat black paint. Bolt channels to the bas with 2-5/16", 18 tpi, 1" long Allen bolts. Put 4 #6 32 tpi Allen bolts into the channels but first file the ends flat with a 6" mill smooth file. The length should be chosen so it sticks out about .25" when holding a plate. Put 3 1/4", 20 tpi, .75" long Allen set screws into the tapped holes. These now will fit any 1/4" mounting rod. Spray paint with Krylon Ultra flat black paint. My total time invested was three hours. A nice touch would be to bevel the front side of the plate holder to 45 deg. You can easily do this with a router and a bearing bit. What you say? Cut aluminum with wood working tools? The truth is it works very well and I have been doing it for years. It works much better than many woods and it is much faster than milling. I once purchased a 9 HP pin router from Boeing that was used to rout airplane parts. We used it to make electric guitar bodies. If you were going to use your table saw a lot for making aluminum parts I would use a ATB grind 60 tooth blade with large blade stiffeners. 3bfa786fa94a0c5a6ddaa4a3b362979c856c775e 0 429 1009 1008 2013-05-12T02:54:26Z Jsfisher 1 1 revision wikitext text/x-wiki Choosing or making a model for a hologram is one of the most important tasks. ==Simple Guidelines== *Pick a reflective object. *Pick an object that is diffuse. *Pick an object you can hold still. *Pick an object that will not rock. ==Making Your Own Objects== There are many materials that work well for making your own objects. Any sculpting skills you have are well used in holography. ===Tips=== *Keep in mind that the object will be brighter if it is more reflective. *Diffuse objects randomize the polarization and can add to the fog level. *Highly reflective objects can cause local places on the film that overload the dynamic range of the recording. (Burn out) *Very bright spots need to be kept from the film plane when making H2 copies. ==Back Drops== You can laminate a transparency to a piece of glass and place it behind the scene and light it from behind. If you live near a large library there are old drawings and etchings in old books that have an expired copyright. These can be scanned and output onto a transparency. Once laminated to a piece of glass for stability, they can add interest to a scene. ==Lighting== Lighting holography objects is very similiar to lighting a photograph of the same object. Any good book on lighting for photography can be useful for holography. If you want hard shadows use the light straight from a spatial filter. If you want soft shadows or fill light pass an object beam through a diffuser. The size of the spot on the diffuser is a good judge of how diffuse the light will be. The main object beam will define all of the shadows present and is called the "Key Light" in photography. It can be straight from a spatial filter or it can be diffused slightly. Ground glass or opal glass can be sued for different effects. This light is often coming from in front, above and to the side of the object. From the other side a dimmer, more diffused light can be used. This is called the "Fill Light". This light serves to fill the shadows to reduce their contrast. Light can be brought from below and behind the object (remember that the film should not be able to see the light source directly) and is called "Back Light". Back light works well for objects that are transparent or have a fine structure that diffracts light well. Hair is a good example. ==Useful Materials== ===Sculpy=== ===Clay=== ===Plaster=== ===Epoxy Putty=== ==Painting your Model== In doing research I have found that Cadmium Yellow reflects 514 excellently while minimally reflecting 457. Cobalt Blue reflects excellently 457 while minimally reflecting 514. And Titanium White reflects both 514 and 457 equally as excellent. ==Links== [http://www.hirstarts.com/index.html Making Fantasy Architechure] 5d23131173da241b8f8ee9d3bfe0d1ce1d7c0d9a 0 430 1011 1010 2013-05-12T02:54:27Z Jsfisher 1 1 revision wikitext text/x-wiki Learning to build a pump cavity allows a frugal holographer to utilize many surplus components. The requirements of a pump cavity are: *Concentrate light on the active medium. *Dissipate the heat generated inside the cavity. *Electrically isolate the flash tube. ==Calculating the Ellipse== [[Image:PumpCavity1.jpg]] The lower the ratio of height to width of the ellipse the more efficient the pumping will be. Since the rod and the flash lamp are placed at their respective foci this meens that the rod and the lamp must be as close together as feasible. Aditional space must be allowed for mounting and machining considerations. ==Material Selection== ===Copper=== '''Advantages''' *Great Thermal Conductivity *Easy to plate '''Disadvantages''' *Poor Reflectivity Requires Plating *Does not take a good polish requiring polishing after plating ===Aluminum=== '''Advantages''' *Great thermal conductivity *Very good reflectivity for Ruby systems *Takes a very good polish '''Disadvantages''' *If not coated the surface can tarnish *Not the best reflectivity for pumping Nd:YAG *Inexpensive and commonly available ===Stainless Steel=== '''Advantages''' *Very hard *Polishes well *Plates easily '''Disadvantages''' *Low thermal conductivity *Difficult to machine *Very chemical resistant *Must be plated ==Polishing the Reflective Surface== Polishing the cavity is like doing any other polishing. You start at the finest grit that will remove the deepest scratch. Once the surface has a uniform scratch pattern you move to a finner grit. Making a fitting for your drill is the fastest way to polish a tube. *Coarse (less than 400 grit) *400 grit *600 grit *800 grit *Red Polish *White Polish ==Plating== ===Nickel=== ===Aluminum=== ===Silver=== ===Gold=== ==Making the Ellipse== ==Designing and Fabricating End Plates== ===Polishing End Plates=== ==Electrical Considerations== ==Water Cooling== a4be1aa2f7036a8f20f74f9c4fb9328f86c5afe4 0 431 1013 1012 2013-05-12T02:54:27Z Jsfisher 1 1 revision wikitext text/x-wiki This is a work in progress. Check back in a few months. ===Manual of Interfermetric Photography=== by A. Berthier, 1895 *Translated by Colin Kaminski. *Note: Colin doesn't speak French so this translation is aproximate. Please see the french version on this site for the original text. ===Introduction=== HANDBOOK OF PHOTOCHROMY INTERF ÉRENTIELLE. Since the publication of the remarkable experiments of Mr. Lippmann, physicists have sought to reproduce them. Some succeeded, others were less happy and obtained only not very encouraging results. The study of successes as well as that of the vexations is extremely instructive, because it makes it possible to determine rather exactly the conditions of the experiment and, by the fact, the procedure to employ to achieve the desired goal. There does not exist, until now, of the scientific raity explaining in detail the method to follow in the by interferential reproduction of the colors; the majority of the experimenters who took the route opened by Mr. Lippmann are of a too tested discretion, with regard to the practical details of the process they are useful. In fact, obtaining perfect tests being still at the present time surrounded with difficulties, each one was ingénié in Jes to better overcome of sound, and such artifice which makes an admirable success with one, gives between the hands of another only a poor result. One would not thus know, for the moment, to give a method absolute and final; it is to better show details the various processes employed by the most skilful researchers, to allow each one to make a suitable selection. One could better start only by quoting the creator himself of the interferential method, Mr. Gabriel Lippmann. ===Chapter 1=== the REPAIR OF the LAYER SENSIBJ, E. 1. - LlppmanlL process Spectrum photographs. - In the month of 1' 1:vrier 1891, Mr.. Lippmann, professor de good Physique it it SOl', announced with the Academy of Science that I! to photographi.er the solar spectrum had arrived. Reports of the Academy of Science (T exile, p. ' l74 and suiv.) contain this important communication completely. Here is the talk: "I proposed, said \ Mr. Lippmann, to obtain on a photographic plate the image of the spectrum with!les colors, in such way that this image deIneurât from now on fixed and p11t to remain indefinitely exposed at the great san day!! to deteriorate. "I could solve this problem while operating with the significant substances, los developers and fixed them current hairs Photographs some, and by modifying sim 1"the ARTIE. - OPERATIONAL PROCESSES. plement physical conditions of the experiment. The essential conditions to obtain the colors Photographs sout two of it: ID continuity of the sensitive layer; 2d presence of a reflective surface leaned with this layer. "I understand by continuity the absence of, grains: it is necessary that the iodide, the silver bromide, etc, are disseminated inside a blade of albumin, gelatine or another transparent or inert mâtière, a uniform way and without forming grains which are visible even with the microscope; if there are grains, it is necessary that they are of negligible size compared to ID. luminous wavelength. "the use of the coarse used emulsions ' today is by there excluded, a continuous layer is transparent except usually a light blue opalescence. I employed like support the albu. mine, collodion and the gelatine, like matters "sensitive ioùure and the silver bromide; all these combinations give good results. "the plate, dries, is carried by a hollow frame where mercury is poured; this, mercury forms "reflective surface in contact with sible layer SEN. The exposure, the development, the fixation, ', make as if one wanted to obtain a negative black of the spectrum; but the result is different: when the stereotype is finished and dried, the colors appear. "the stereotype obtained is negative by transparency, it be-with-ùire each color is represented by its complementary. By reflexion, it is positive, and one sees the color itself, which can be obtained very brilliant. To obtain positive thus, rél' is needed 3rd. 1st or sometimes to reinforce the image so that the die. could photographic has a clear color, which is obtained, as one knows, by the use of liquors acidùs.. " One fixes at the soda hyposulphite followed neat C Inva' ges: I have vérifl, 6 that then the colors resisted the light électrique.la plus inlens ". " The theory of the experiment is very simple. Read. incidental mière, who forms the image daus the darkroom, interferes with the light rétléchie by mercury. It is formed, consequently, in the interior of the sensitive layer a system of fringes, i.e. the maximum luminous one and obscure minima. Be maximum only impress the plate; following the photographic operations, these maximum remains marked by more or less reflective money deposits which occupy their grip. The sensitive layers so find divided! by these deposits in a series of blades minees which have for épaisscur J' interval which separated two maximum, it ost-with-statement a domi-Ionguor of wave of the incidental light. These!times minees has thus precisely I thickness necessary for repl' to oduir J) Los visible colors on the stereotype are thus of comparable nature that those of soap bubbles. They are only more pure and brilliant plu!l, at least, when the photographic operations gave a quite reflective deposit. That is due with what it is formed dans the thickness of the sensible layer a very great number of superimposed thin blades: approximately 200, if the layer has, for example,tu miIlimèt~e. For the same reasons, ]a considered color is of as much pltJs pure that the number of the reflective layers increases. These layers form, indeed, an in-depth form of network, and for the same reason as dnns the network analysis by reflexion, the purity of the colors is growing with the number of the elementary mirrors, U In his first experiments, Mr. Lippmann was useful himself of the process to the collodion and the albumin of Taupenot. This process presents the avantages' those at collodion and albumin, in the sense that it perm6& of conser\' gold los ices after their preparation. An inherent defect with the process on albumin lies in the difficulty in obtaining homogeneous layers (exemptesde bubbles, etc). Mr. Taupenot, by extending albumin on a porous surface of collodion, faH to act porous fibres of this layer on the microscopic bubbles, so as to do them disparaitl:e; One can be useful oneself of sensitized and washed collodion, or collodion mêmo not iodized (Gaumé). The ice, cleaned well, is covered with ordinary collodion, which one sensitizes and which one washes as for the process,au ()ollodion. L~glace being drained, after the dèrnièr washing; 011' iarècouvrè('. from albumin, exactemeut as one extends collodion, I and one lets run out excess in a special bottle. 011 employs, for this preliminary albumenizing, least possible of albumin, which is only used to drive out water and which one throws then. When the ice is well drained, one covers it with new albumin. The ices are dried like the ices with tannin. They are preserved inrléfinirrient. One sensitizes them a few days before making use of it I they conser\' ent this sensitivity during one year. One operates this sensitizing while plunging them san, S downtime in a bath C *Eau 100" *Nitrate d'argent. . '. .. ... ... .. . . ::. 10" *Nitrate de soude 10 *Acide acétique cristaIUsable . ... , 10 The time of immersion should not exceed twenty seconds. The ice, withdrawn of this bath, is plunged in the distilled water contained in a wood tank, where it remains ten garlic minutes less, then in a tank filled with ordinary water. Withdrawn, it is abandoned Li the desiccation, supported against the wall, and dans the most complete darkness. The exposure to the light is a little shorter than with ordinary albumin (1). The plates obtained thus are extremely transparent: their grain is very fine, but their SENsibility is relatively low, If one substitutes the bromide ù. ' the money iodide, one makes a success of it slightly exalter this sensitivity. The plates are then prepared in the manner sui praises: 011 begins raI' to cover the ' ice with collodion which one sensitizes in a nitrate bath, then, after lavn:ge, one covers it, collodion of a layer a]bumineuseformée by an albumin solution containing} ù. ~ for 100 of potassium bromide. The plates "once dry, are subjected during two minutes it a bath of *Water. 100 parts. *Acetic silver nitrate 10 *Acid 10 Like all the preparations with silver bromide, this one presents a maximum of sensibilitépOUL' the blue area of the spectrum and a minimum for the yellow and red area: it is thus necessary to employ a bain..sensibilisator (solution of cya-, nine with 1: 25000). The développeml-MT is carried out either with revealing the addes, or with the reducers alcali~s, or better still with both, by employing them su~cessivement. One starts by revealing the image with a pyrogallic acid solution it. 1 per 100, then one, _ termine' with a pyrogallol solution slightly alkaline, container unpeu of potassium bromide. The fixation takes place in a soda hyposulphite bath it 15pOl~r 100: the layers being very thin, it - - quickly is finished, If one does not fear to prolong the exposure time, one can be useful oneself of the process on albumin likely to give good results: * Albumin 1. * Iodize potassium 10. * Iodine 0", 5 The potassium iodide is dissolved in some water drops, then iodine is added there. The whole is then thrown in the albumin, which one beats in snow. After Duit of rest, one elutriates the liquid in a test-tube. Using a pipette, one takes albumin in this test-tube with the average part of the liquid, which is always clearest. The extension of albumin on the ice is extremely difficult. One sel'. transfered oneself of a spinner or a centrifugal apparatus. ~es ices, once albumenized, is preserved indefinitely. One sensitizes them in the following bath: *Eau, . ".'. , l00t'C' *Azotate d'argent cristalllsablc 6,. *Acide acétique cris talUsablc.. .. ... .. . .. 12 The nitrate solution fiItrée is versed in a vertical basin out of glass, in which the ice is plunged without downtime, using a hook also out of glass. The layer of albumin, qui' was originally transparent, becomes slightly tender offer line. Generally, one lets it remain uansle bath of money only ten seconds to one minute (1). To wash then and dry with, the shelter of the light. To expose to the darkroom, the indications of Mr. Lippmann. The installation is extremely long and can only with difficulty be specified. Procèdé Lippmann with isochromatic plates. - As of May 189.2, Mr. Lippmann supplemented first stated that it had made his discovery, by the communication suivante': "In the first communication that I had the honor to make with the Academy on this subject, I said. that the sensitive layers that I employed then lacked sensitivity and of isochromatism, and which these defects were the principal obstacle with the application of the method which I had imagined. Since then, I have réussi to improve the sepsible layer and, although it remains still much to be made, the new results are rather encouraging pour' that I allow myself to make share with the Academy of it. ), On layers of albumino-bromide of money, made isochromatic by the azaline and cyanin, I obtain very brilliant photographs of the sp' êctre.. All the colors come at the same time, even the roug(;1, without interposition of coloured screens, and after an installation comp' small channel between five and thirty seconds. "On two of these stereotypes, one notices that the colors, seen by transparency, are very definitely complementary among those which one sees by D inflection. The theory indicates that the colors COM -, posed that cover the natural objects would have goes laughed el' Photographs some as well as the simple lights of the spectrum, It was not less necessary to check the fact in experiments. The four stereotypes which I have the honor, to subject àl' Académie represent rather various objects accurately: a stained glass with four colors; a group of flags; a ' orange dish surmounted by a red poppy; a multicoloured pel' "roquet. They show that 10 modelled is returned at the same time as the colors, "Le~ flags and the bird required from five to ten minùt, are of installation to the electric light or the sun. The other objects were made after many hours of installation to the diffuse light. It remains, therefore to make still much before returning the procédépratique. " Pl' océdé Lippmann ù the gelatine bichJ' oJJwtée. ~ One knows that a layer dries of albumin or of dichromate gelatine is modified by the light: the organic matter, becomes less hygrometrical. , the majority of the processes of photomechanical impression employed in industry are founded on this, action of the light ' A layer of albumin (or gelatine) bic.hromatée, run and dried on glass, est' exposed with the darkroom, leaned with a mirror of mel' cure. It is then enough to put it in water for voi; apparaitre colors; this washing it it pure water, by ènlevant bichromate, fixes the test at the same time as it develops it. The image disparait when one dries the plate, to reappear each time that it again is wet, The colors are very brilliant; one sees them under all the incidences, i.e. apart from the incidence of the regular reflexion. By looking at the plate by transparency, one clearly sees complementary colors seen by reflexion, The dichromate gelatine is composed in the same way, except that the colors appear in their place, not when the plate is wet into full, but when one, makes it slightly wet into blowing to his surface. The theory of the experiment is easy to make. Comme' in the case of the sensitive layers containing a money salt, the mirror of mercury gives place, during the installation, with a series of maxima' and minima of interferences. The maximum ones only impress ln. layer, which takes, pn.r continuation, a In.mellaire structure and is divided into layers alternatively inflatable and ' noninflatable pn.l' the en.u. ' fant that the plate is dry, one n.perçoit pn.s of image; but, as soon as water intervenes, it!! left the layer not impressed soak some; the index of refraction varies consequently periodically, in the thickness of the couc, He, just as the capacity reflectors, and the coloured image becomes visible. When albumin is employed, it fn.ut to extend a layer of this liquid on glass, ln. to make dry and, moreover, to coagulate it by bichlol' RUE of meroure before plunging it in bichromate of potasse', Without this precaution, not impressed albumin would dissolve at the time of washing it it pure water. One can pass to bichloride mercury either front, or after the plate received the luminous inlpression (!). These di\' strops experiments of Mr. Lippmann has excited at the most point the interest of the erudite world. Collected initially it it foreign with a skepticism not disguised, they forced the attention by their highly scientific character and the assumptions that they confirm. Also incredulity it made place it fills with enthusiasm it, and one currently sees eminent physicists and skilful experimenters to compete of zeal to improve the obte- results. naked. It would be unjust not to note that, thanks to the contest of these goodwills, in particular of France and Germany, the question notably progressed. We quickly will review the various methods suggested either like alternatives, or like improvement a.u procédéLippma.nn. With the first category are attached all the tests which derive more ' or less directly of the ancians experiments C Becquerel and Poitevin. Their list would be long. It suftlm to quote quelquesuns of it: those C I\:rone, of Saint-Florent, etc. The future does not appear to be reserved to them. With the second category, i.e. it that of the improvements. are attached the processes of MISTERS Lumière, Valenta, ' 1' hwing, etc. C all the eXj)él' imentateul' S which are occupied of this delicate question, ' i\I. Louis Lumière is certainly that which innovated with the most bonheur~ M~I. Valenta and Neuhauss also succeeded in it obtaining good photochromies, as the success of the illustrated conferences of pro attests it, jections which they gave in Vienna and ù. Berlin (1). , ====Krone Procedure==== In the current of the year J8D2, Mr. Krone makes a success of ù. to obtain color tests without the use of a reflective mercury surface. To this end. it uti!is' has the reflexion back luminous radiations on the su~face inter~e C the plate glass, to form the necessary fringes ù.la reproduction of the colors. To increase the action of glass, it recouv~ait 13 plate of a tight black velvet against the layer, of albumin. The colours obtained by this process are less beautiful than those that-gives a mercury mirror, but they are perfectly perceptible; The theory of the phenomenon is rather complicated, because diffraction should certainly be fairei~tervenir;: Since then, read. Krone(2} consigned the result d~ its experiments in a Work where it exposes aùssi work of its precursors. In his opinion, the condions necessary to obtain a correct reproduction of the colors are determined by the following observations: *l0 It is essential that the sensitive layer is perfectly homogeneous. *20 When the sensitive layer exceeds a certain thickness, the colors are denatured or disappear completely. Everywhere where a grain of dust is, one observes this phenomenon in all his variations. *30 the formation of the colors corresponding exactly to those of the original depends on the following circumstances: . (has.) Proportion exact and difficult to determine sensitizer compared to salt haloYde of money, this last being in the layer with the ét' At of extreme division; *(b) Of the degree of heat to which drying takes place; *(c) Of the duration of the installation and I intensity of the lnmière; *(d) Of the development. When one or the other of these conditions is not filled exactly, one observes the abnormal production of coulel~r~ false or the disappearance of couleurl! true. *40 the percentage of moisture of the plates moditie D sultat, while varying the colors *50 In the case of the photography solar spectrum, height of the Sun above the horizon intiuo on the value of the colours obtained: IG 1"PART. - OPERATIONAL PROCESSES. *60 actinic intensity of an electric arc lamp whose positive charhon is placed at 36 ====has, - Process of Saint-Florent ('),==== An ordinary plate with money gélatinobromure having been exposed under glass coloured with the rays di-. rects of the sun during fifteen to sixty minutes, then fixed without development and washed after fixation, reproduced the colors of the original if one placed SUl' it will tra -. jet of the pencil of light an orange screen-fillre, the colors are visihles by reflexion when HT layer is wet. Here the talk of the procedure followed by Mr. of S~int-Florent, such as it gave it in a communication made to the meeting of the French Company of "Photography of December 2, 1892: "a plate with gélatinobromure is exposed to the sun behind a yerre colored (glass of magic lantern) during a time which can vary fifteen minutes It one hour. With leaving the frame, the plate is not pas dé\' eloppée, but Ilxée immediately in a concentrated hyposulphite bath and washed with the greatest care "In front of colored glass, one had care to place a screen out of orange glass. Qn can also make use of the successive screens indicated by Mr. Berget (red, green etbleu). "At leaving the last bath of washing, the test has by réllexion the colors of the model. These colors, which are very low, but nevertheless distinct, disappear almost completely when the ice is dry "Lcs colors are more sharp and the larger speed if, before the exposure, one plunges the ice to gélatinobromure in a silver nitrate solution to iD for approximately 100, ' added with alcohol in a strong proportion. These plates, without any washing, preserve their sensitivity long enough. *This sensitivity increases pal' the addition with the bath of one or two mercury nitrate drops by 100cc of solution. *This last bath Sc does not preserve. *U The colors by transmission are generally complementary colors seen by reflexion. *Please notice that I do not develop the tests, and that there is no mercury mirror in the experiment which I have just described. The reflexion incidental rays is done about normally on a reflective surface, which is most probably the posterior trauche of the significant substance and not that of the ice. D Principal conditions of the so remarkable experiment of Mr. Lippmann trouvent.donc with louse close realized, and the phenomena of interference pro' are duisent in about similar circonstances'. D All handling is done, without any in convénient, with a weak diffuse light. D The orthochromatic plates of Mr. Lumière give good results, but I could not encoro pass to me from screen. D If, garlic place of plate to gélatinobromure, one employs plates with the gélatinochlorure (Perron mark), one often obtains tests whose eouleÙrs are (Pa!, reflexion) complementary of those of the model. I could not, until now, to return to me account of this anomaly "In the meeting of the 7 aoQt 1891 (Bltllcti1~, of September), I made known the tests that I had made by means of the dichromate gelatine appliquée.sur polished metal plate. D I come from the r.épéter with albumin. D The results obtained are encouraging, but still quite incomplete. The colors have a great glare, a true metallic lustre; they my Trent only when the plate is dry, contrary result with that which has just obtained ~f. Lippmann in CUAI'. 1. - PRI::PARATIOll RE I.A COUCIIE SE"Slnl.E. IV brilliant experiments exél:utées by means of the dichromate albumin applied to glass "It is as extremely singular as the tests with gélatinobromure that I have obtenuos are visible (I speak about the colors) only when the wet ice ost, whereas 1\ 1. Perhaps Berget, in its Works and dllns its conferences, expressly known as that the colors se' show only when the ice is completely dry "That is due with the suppression of the révéllltour in the process of which I have the honor to return account to you, suppression with which I was brought in répétllnt the famous experiment of Yung." I have fllit some essllis by means of the black chllmbl' E; one obtains many épl' euves stained glasses and landscapes, m~is it is very long, and the visible colors son' tà sorrow. One thus needs still well DCS experiments before arriving to the complete solution of the major problem by the method mentioned above "to preserve the color tests, I imagined a kind of vertical basin whose former face is out of glass. This basin is full of slightly carbolic water, and one places the test there on black bottom J the face glass is framed and presents the aspect of a genuine framework of photography. "By finishing this long letter, I believe duty to announce you a rather singular fact: "Hunt, about 1845, managed to print the solar spectrum with its couleurd, but the colors disappeared with the fur and measurement which the sheet dried 20 1"PART. - PROCESSES OPÉRÂTOIRE. of paper on which it operated. You will find, in all its details, this experiment in the Roret Handbook, 18G2, tom~ II, page 297. D What proves that there u' is nothing again under the sun ".' . . Another curious fact, also announced by Mr. de Saint-Florent is as follows: "I arrived, written ~r. of Saint-Florent, fi to produce color tests by means of iron salts to the maximum. "I employ the bath indicated quite simply, a long ago, by Poitevin: *Water. 100" *Perchloride of fcr 10 *tartaric Acid 5 "As I did not have a plaqnes with the simple gelatine. I took the pl!\ques ones with the gélatinobromure of which I removed salt haloid of money to average C hyposulphite "Aprè.s of the lavag' are neat and a complete drying, the plate, whose gelatine became insoluble, is exposed behind glass colored pendant\.un rather long time. After the exposure, one washes it it tepid water; the insolated parts became more or _ less soluble, and a épl' euve is obtained that devnnt should be dried quickly fire. "When the image is dry, it presents neck their light, among which the red, yellow and breadth ert. The purple ones and the blue ones are it pains visible. "These colors are not seen under all the incidences; they should be observed under the same conditions as in the first experiments of Mr. Lippmann. "I also obtained turns dichromate color with Ia.gélatine applied to glass. One develops with the cau cha.ude. The colors are shown as in the experiment above. "It appears certain to to me that with a mercury mirror the results must be infinitely better (1)". In another communication at the French Company of Photography, Mr. de Saint-Florent thus summarizes the results of his experiments: 1. One takes a paper with the chlorl1l' E of built-in money daus a vehicle like collodion, the albu~ mine, the gelatine, etc. Papers with the celloïdiJ1c are excellent "One exposes this paper to the diffuse light until the moment oil it starts to show traces of metallization: One then applies it, without no preparation, in a positive frame, behind glass colored "At the end of several hours of exposure in full sun, one obtains a positive image which presents at little p1' ès, on a a little dark bottom, all the colors of the model. D 20 a paper sheet to the gélatinochlorure (money excess) are exposed during several hours Photo-gazette (t), 1893, p; 55. behind glass of magic lantern and place to a negative test presenting gives some traces of colors. The image changes, it is -âdire that it becomes positive, if, to leaving the châssi~, one exposes it to sunlight. The colors already a ' little appa.rgraft become more sharp and those which were latent. show souventa.près a duration more or less prolonged. The greens and especially the ja.unes come very with difficulty "These. tests have a certa.ine stability, ma.is they are not fixed ". With papers with collodion-chlorùre.. (celloYdine, etc), the speed is larger, and the ve1' ts and the yellows come better, if one applies to the test, av' ant its exposure on the ground have, a little varnish to terpentine (very diluted). " ====4. Process CH R. ThwJng==== Mr. CH R. ' the hwing, with an aim of increasing SEN. sibility of the plates, A. proposed into 1892 of sq;bstituer money collodiobromure to albuminiodure. . formulate indicated is the suiva.nte: \. *Cadmium Bromuro,; . 25" *Alcohol Acid 250" *chlorhydl' Ique... . . . . . . . ... . . . . . . . ... ... . . 5 One mixes Sec this solutionà, 40cc of ether and one adds 2sr pyroxylin' E, then, drop by drop, une' alcoholic solution C nitrate d~argent to 10 per 100. It is necessary to extend. the mixture on the plates before it was transformed into emulsion: the sensitive layer is blue pale, slightly opalescent. ====6. -:Procédé Kltz (').==== Mr. Kitz announced this fact that certain positive papers, Obernotter paper with money gélatinochlorure (of Emile Buhar, in Mannheim) for example, are likely to reproduce the colors, when one isolates them under coloured glass. The polychrome images obtained cannot be fixed. It is necessary to bring closer this fact coux published by Mr. de Saint-Florent. This experiment is attached rather to old ~é thodes of Becquerel and Poitevin. The colors are né.anmoins due probably to a phenomenon of interference. ====6. -:Procédé Lumlére.==== As soon as the experiments of Mr. Lippmann had been. published, ' MISTERS Auguste and Louis Light, of Lyon, undertook to repeat them. Of all the experimenters who la.ncèrent themselves in this way, they were more ' happy;! because they not only succeeded to reproduce the colors of the spectrum, but they were able to improve the process and to make it practical in a cèrtaine measurement. Btant given the importance of the results to which they arrived, - as the splendid polychrome stereotypes testify it which one could see in various exposures or conferences, -- we will completely quote their first communication made it it French Company of Photography on Celt question, on May 5, 1893. "As of the début' of our experiments on the Photography of the colors according to the method, if remarkable, imagined by 1\1. professor Lippmann, we had proposed to make c:onnaitre the process which had led us it it obtaining, of the tests which we had presented at the French Company of Photography, but the irregularities quç we note then retained us and we have préféréattendre a(ln to give indications pr6cises allowing to surely arrive it of good results. ) That us re\' endiquer is allowed, very of A., edge, priority on process which Mr. Valenta made known, of Vienna, and who consists it mélangér, to obtain emulsion, if as well is as one pJisse to thus call the preparation obtained, deux' gelatinous solutions, one containing ùn soluble bromide, -, the other of silver nitrate. NoÙs, indeed, made connaltre, in one, communication on March 23, 1892, it it Company of industrial Sciences. , of Lyon, the method which we follow then. and which, CllAI'. 1. - the nÉI' AnATlO~ Of COUCllE SENSIULE. 25 as you will see it, differs very little from that in diquée by this expérimentateur' (1). "the following formulas were established empirically, that goes without saying, but we offorcés ourselves, in the very many experiments which we made, to proceed with method, never not changing, at the same time, which only one of the constituent elements, as well with regard to the emulsion as in what looks at the revealing one. From where the quantity of tests required and the extremely long duration of time that we have dCl to devote to it "to obtain the sensitive emulsion, the following solutions are prepared: With. - distll\ée Water.... "........ 400" GéIMino ' 20 "One adds to the solution C half of solution A, then other half of the latter is addi, tionnée i1 D. One mixes then these two solutions ' 1 ';' (')"Vno solution of 5 pOUl' iOOde gélatino ost addiUonnéo of it. 2 pOUl' 100 C bromuro, chloride, Iodide solublo. Of auiro Pa T, tlno soiutlonsemblable C gelatine is addHlonnce of 2 à3 for 100 C nltrato of argont. It sufllt Llo méiangOl' cos two soluLions for rOl' l1101' I' émulsiou, if it or pout appelol' thus 10 result of the mé~ ' lange, then C dyalisol', to obtain to the preparation of which us uous sommos sorvis." (Accounts I end custom of Socic!te! ielles backs Soioncos ine/usll' of Lvon.) gelatinous by pouring the liquid containing silver nitrate in that containing potassium bromide. One adds then with a suitable coloured sensitizer: cyanin, purple of, methyl, érythrosine, etc, pui~ the emulsion is filtered and couché.e on plates. This operation must be done. with the spinner, the temperature. solution not exceeding 400. "One makes take the layer in frost, then the plates are immersed in alcohol, during a very short time, treatment which allows the complete damping of surface, and finally one washes in a current of cau. The layer being very mean, washing does not require that very little time "This method present, on that indicated by 1\1. Valenta, the advantage of avoiding the enlargement of the silver bromide grain, enlargement resulting from the washing of the mass and the heating required for the recasting, and of allowing the obtentiQn plates of a complete transparency. Moreover, one must avoid, for the same reason, the use of a too great soluble bromide excess, "the plates having been washed suffisammen\.sont put to dry, then, before employment, treated, during two minutes, by the following solution: Distilled water 200"Nilrato of argont il' acetic Aclde.. ... ............... . . ....... ... . 1 "This last treatment makes it possible to obtain images much more brilliant. It increases, moreover, the sensitivity, but rather quickly brings the deterioration of the sensitive layer. One dries again, then the plate is exposed, in accordance with the indications given by Mr. professor Lippmann.)) ====7. - Prooédé Va.lenta.==== At the same time as Mr. Louis Lumière continued in France his remarkable experiments, Mr. E.Valenta.obtenait in Germany of the similar results by not very different means. It is right to note however that the priority belongs incontestably to the young French scientist whose photochromies had been presented at the Company industrial Sciences of Lyon since 1892. Mr. Valenta exposed làrésultat his research in a certain number of German periodicals (Photographische Çorrespondenz; Photographisches Wochenblatt), and in particular in a Work which it published on this question: Die Photogl' aphy in natiirlichen Farben CHalle. a. S., KnapPi -1894). . To obtain the continuity and the homogeneity of the layer, - essential conditions of success indiquées' by Mr. Lippmann, - Mr. Valenta observes that all the efforts must tend towards this goal: to prevent the emulsion from mùrir. Ammonia, heat make mflrir the emulsion and increase its sensitivity, but also the particle sizes: they will thus have to be avoided. One will prepare two solutions with also low moderated ture that possible (300 to approximately 350), one being composed of the quantity necessary of silver nitrate, the other of the gelatine and bromide, then one will pour the first in the second: no precipitate is formed, the solution tt' ouble not, but becomes slightly opalescent; it should be employed earlier ~e possible, tout' delay supporting the production of a coarse grain. Here a' elsewhere the exact formula, fruit of patients research. on behalf of the author: A. Gélatine 10" Eau. .. .. .. . .. .. ... ... .. 300" Azotato d'argenl., . ... , .. . .. . 0 G' B. Gélatine 20" Eau .. . ... .. . . .. .. .. .. .. .. .. .. ... . .. . ... 300" Bromure de potassium .. 5., These solutions are cooled it 350 C; then, in the obscure laboratory, solution A is slowly versed in the solution B, while stirring up constantly. When the mass is quite homogeneous, one plunges it in approximately was of alcohol with 90 per 100, then one stirs up it with a rod of glass until all the bromurée gelatine is adherent for him. One carries out then washing as for an emulsion ordinkiro, i.e. one divides it into menus fragments which one places a few minutes in running water. 3rd: - well washed milking is then molten at as low temperature as possible in a bell jar; one adds the quantity of water necessary to reform the primitive volume of 600", then one filters and, if there is place, one incorporates with the mass the dyes necessary to obtaining orthochromatism. If one wants to avoid this last operation of fusion of the mixture, one can adopt the artifice indicated by Mr. Lumière. The emulsion is not precipitated, but one proceeds with spreading immediately after the mixture of the two solutions A and B. The plates are placed on a quite horizontal marble support until. what the sensitive layer is taken. One then washes quickly approximately fifteen minutes with running water, Co which is enough perfectly to remove all soluble salts. Da.ns all the cases, the emulsion must be filtered before being wide. To this end, one will be useful oneself with a\' anta.ge of a funnel whose bottom is furnished with a glass wool plug or better still of hemp ita.lien than one will have beforehand made boil 3.Yec a solution of very wide potash, then washed with large water. N is necessary of prendr.e guard, when one proceeds with the spreading of the emulsion, quela sensitive layer does not exceed a certain thickness. Mr. Valenta noted that the best results are obtained with leseouches thinnest. If there is not the practice of this kind of operations, one could be useful oneself of a tOllrnant plate on which one will place the ices: grace it ]0. centrifugal force, the emulsion will be distributed amusement in all the directions, One will observe moreover than, lol' S of the preparation of the plates, it is essential to subject them to an alcohol bath diluted before final washing I if one omitted this precaution, one would notice that the sensitive layer is covered small bubbles of air. who adhere to the emulsion and prevent consequently water from producing its action. When the sensitive layer is dry, one will thus immerse the plates in a cuv.ette containing wide alcohol and one will agitate the liquid until the whole surface is well wet and which all the bubbles disappeared. One will finish by an energetic washing under an apple of watering-can, then in running water (twelve to fifteen minutes) and one will obtain perfectly transparent ices thus, presenting by reflexion a light opalescent colouring. The plaSlue is then ready to receive the impression}umineuse one, If one had suddenly exposed it to the ammoniacal vapors, the sensitive layer would bleach quickly in consequence of the enlargement of the grain of the emulsion. One could not think any more it of obtaining the reproduction of the colors. Mr. Valenta noticed that the emulsions with the money chlorobromide gave results more brilliant than those to bromide, It indicated, for this purpose, the following formulas like most practical: A. Water.............. ... ....................... G 61allne..... . ..... ..... ... ... ....... ....... D, Water..... Lunar caustic.. . . ... ...... C, Water.. . . . . . . . . ... ... . . . . . . . . . . . ..... . . . . ... Bromide ùo potassium...................... Chloride ùe sodium.................. \' 200 " 10.' 15" 1 GI',5. A. Eau.. .. .. .. .. .. .. . .. . .. .. .. .. .. .. .. .. .. .. .. . G 61allne .. .. . . .. .. . .. .. . .. . .. . .. .. .. . .. .. ... D, Eau ..... Azotate d'argent .. . . . .. . ... ... C, Eau.. . . . . . . . , . . .. . .. . . . . . . . . . . . . .. .. . . . . . .. . Bromure ùo potassIum...................... Chlorure ùe sodium... ............... 15" 081',35 0",35 One divides A in two equal parts, one that one pour in B with 3: 0 or 400, the other in G One mix well and one pours B in C. A. Water 300"GélaLine 10. Silver nitrate... G N Eau 300"Gelatine..... 20. Bromide of potasRlum 2, -, 4 Chloride of sodium..... L,5 cdc666e1c3c28b3c3fdc1422caf750814eef000c 0 432 1015 1014 2013-05-12T02:54:27Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.mbenyon.com Margaret Benyon's Website] [[Image:Mbenyon.gif]] Initially a painter, Margaret Benyon began to make holograms in 1968 when holography was available only to scientists. Her aim was to take holography out of the science lab, and to enlarge the boundaries of what was traditionally seen as fine art. Her early body of work with holography was an exploration of those aspects that were unique to it. Living in Australia with her partner and two small children in the 1970's led to work that was more humanist and cross-cultural. On returning to the UK in 1980 she began to use the human body exclusively, in a personal, partly therapeutic way. More recently she has been exploring the naturalisation of holography, and the female aesthetic. Her work with creative holography has been recognised with academic fellowships, artists' residencies, and a number of other art and holography related awards. She is currently listed in the International Who's Who, and in the millenium year she was awarded an MBE by HM the Queen in the New Year Honours List 2000 for services to art. Her work has been seen in a large number of exhibitions, in countries as far apart as the USA, Canada, Portugal, Italy, Australia, France, Germany, Japan, and China. Her works are in a number of public collections, including the Australian National Gallery and the Victoria and Albert Museum, London, and in an undocumented number of private collections world-wide. In 1994 she received a Ph.D. from the Royal College of Art, London, for her research and activities in art holography. Margaret Benyon made most of her holograms in her home studio on the south coast of England for 23 years. This was a basic, low-tech, non-commercial holographic studio, one of very few in existence. However, she also used more sophisticated international labs, and in 2005 moved to Sydney, Australia. She is currently an honorary Professorial Visiting Fellow at the College of Fine Art at the University of New South Wales, and continues to work internationally from Australia. 20b96fb2add961d59d6fccd5865f3ffb6498dacc 0 433 1017 1016 2013-05-12T02:54:27Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Mmueller.jpg]] Martin Mueller Born and lives in Zurich, Switzerland. Used to work as a freelance journalist, essay writer and translator. Caught the holography virus (1980) when writing an essay on holography (which put emphasis on forerunners in the arts mainly). Run a small holography business with Ralph Kuehne for more than ten years. 1998 begin of friendship and cooperation with Sergio Oliveira (Sao Paulo, Brazil), which led to the development of a new photopolymer system [http://www.polygrama.co.nr/ Polygrama]. cfd3ff4e3ecac1d5d56db9280a1b575f0b50d346 0 434 1019 1018 2013-05-12T02:54:28Z Jsfisher 1 1 revision wikitext text/x-wiki Under construction - please feel free to add... The best calculator available on the net is the Google search box! [http://www.google.com/help/features.html#calculator Google Math!] For example if you enter: c in furlongs/fortnight It will give you the speed of light in the most esorteric dimensions imaginable. the speed of light = 1.8026175 × 10^12 furlongs / fortnight ==Math Links== [http://mathforum.org/library/topics/basic_algebra/ Math Forum] ==Simple Trigonometry== It is helpful to read equations aloud until you have some experience with them. Here is a guide on how to pronounce different equations. * sin(θ) is read as "the sine of Theta". * cos(θ) is read as "the cosine of Theta". * tan(θ) is read as "the tangent of Theta". [[Image:TrigAngles.gif]] In a right triangle the: * sin(θ)=opposite/hypotenuse or a/c * cos(θ)=adjacent/hypotenuse or b/c * tan(θ)=opposite/adjacent a/b ===Pythagorean Theorem=== a^2+b^2=c^2 - Read as a squared plus b squared equals c squared. The Pythagorean Therom is used to find an unknown side length if the other two are known in a right triangle. ===Angle Theorem=== The sum of all angles in a triangle are equal to 180 degrees. ===Examples=== With sin, cos, tan and the Pythagorean Theorem you can solve all of the sides and angles in a right triangle if any 3 parameters are known. For Example: If a=7 and b=5 then 7^2+5^2=c^2 49+25=c^2 74=c^2 sqr(74)=c 8.6=c Now we have all three sides. sin(θ)=7/8.6 sin(θ)=.814 θ=arcsin(.814) - Pronounced theta equals the arc sine of point 814. θ=54.5deg Now we have two angles (90 and 54.5): 180=90+54.5+(our missing angle) 180-90-54.5=our missing angle our missing angle = 35.5. Now we have solved all of the sides and angles of this right triangle. I choose to use Pythagorean Theorem, sin and the angle theorem but we could have used other choices. ===Simple Identities=== *tan(θ) = sin(θ) / cos(θ) = a / b *sin(-θ) = -sin(θ) *cos(-θ) = cos(θ) *tan(-θ) = -tan(θ) *sin^2(θ) + cos^2(θ) = 1 *sin(2x) = 2 sin x cos x *cos(2x) = cos^2(x) - sin^2(x) = 2 cos^2(x) - 1 = 1 - 2 sin^2(x) *tan(2x) = 2 tan(x) / (1 - tan^2(x)) *sin^2(x) = 1/2 - 1/2 cos(2x) *cos^2(x) = 1/2 + 1/2 cos(2x) *sin x - sin y = 2 sin( (x - y)/2 ) cos( (x + y)/2 ) *cos x - cos y = -2 sin( (x-y)/2 ) sin( (x + y)/2 ) ===Law of Sines=== Given Triangle abc, with angles A,B,C; a is opposite to A, b oppositite B, c opposite C: a/sin(A) = b/sin(B) = c/sin(C) ===Law of Cosines=== *c^2 = a^2 + b^2 - 2ab cos(C) *b^2 = a^2 + c^2 - 2ac cos(B) *a^2 = b^2 + c^2 - 2bc cos(A) ===Law of Tangents=== *(a - b)/(a + b) = tan 1/2(A-B) / tan 1/2(A+B) ==The Greek Alphabet== *Α - Alpha *α - Alpha Lower Case *Β - Beta *β - Beta Lower Case *Γ - Gama *γ - Gama Lower Case *Δ - Delta - Sometimes spoken as "the change in". *δ - Delta Lower Case *Ε - Epsilon *ε - Epsilon Lower Case *Ζ - Zeta *ζ - Zeta Lower Case *Η - Eta *η - Eta Lower Case *Θ - Theta *θ - Thete Lower Case - Used to represent angles. *Ι - Iota *ι - Iota Lower Case *Κ - Kappa *κ - Kappa Lower Case *Λ - Lamda *λ - Lamda Lower Case - Used to represent wavelength. *Μ - Mu *μ - Mu Lower Case *Ν - Nu *ν - Nu Lower Case *Ξ - Xi *ξ - Xi Lower Case *Ο - Omicron *ο - Omicron Lower Case *Π - Pi *π - Pi Lower Case - The diameter of a circle divided by it's diameter *Ρ - Rho *ρ - Rho Lower Case *Σ - Sigma - "The sum of" *σ - Sigma Lower Case *ς - Sigma *Τ - Tau *τ - Tau Lower Case *Υ - Upsilon *υ - Upsilon Lower Case *Φ - Phi *φ - Phi Lower Case *Χ - Chi *χ - Chi Lower Case *Ψ - Psi *ψ - Psi Lower Case *Ω - Omega *ω - Omega Lower Case 9df6bfbd3268e6495f71e30728bdb32d5ccf9fe7 0 435 1021 1020 2013-05-12T02:54:28Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:MichaelHDag.jpg]] Born in Houston, TX in 1966 I became enamored with holography in 1984 soon after seeing the first National Geographic with a hologram of an Eagle on the cover. Up to that point I'd never asked for much beyond the typical geek-oriented holiday and birthday gifts such as telescopes, microscopes, circuit kits and the like but that summer I bought the Holography Handbook and soon after asked my parents for a laser. My mother liked to tell the story that after I asked for a laser she called up my father and said "he finally asked for something. He wants a laser." Unlike all her other kids I didn't ask for a car (I was 18 by this time) but asked for something right out of left field as far as they knew. My dad scrouged a .5mW laser out of a telecopier and I set about building a 4'x4' sand table in my bedroom. I made a few transmission holograms over the next year but nothing wonderful. I did end up cracking the foundation though. Fortunately my parents were forgiving. Since diving back into holography in 2003 I've made hundreds of holograms, some not worth keeping but I keep most anyway and have made many more worth keeping, selling, giving away to friends and associates as well as hanging on my walls. I enjoy sharing what I know in person, on the Holography Forum, through the PCG and tutorials on my web site. The full body of my work is available on my web site at [http://holography.dragonseye.com Dragon's Eye Holography] a31af0d54055130efaef6b2f1b52b60d7a75bb74 0 436 1023 1022 2013-05-12T02:54:28Z Jsfisher 1 1 revision wikitext text/x-wiki Tools needed: * vise held down with tnut etc hardware. A good vise is KURT with better than 6" opening preferred. * set of different height parallels 1/8 inch thick for small parts and 1/4 inch for the larger ones. * Dial Calipers * end mills: center cutting 2 or 4 flute. * collet system to hold end mills. Spring collets like the ER40 on larger mills are nice. * DRO (digital readout) is a nice feature to have but not necessary. * drill chuck and drills * rubber mallet Basics: Make sure your mill is trammed [http://www.jjjtrain.com/vms/mill_movments_vert_hd.html] Place part in vise on top of parallels and tighten vise. Use rubber mallet to pound down the part and tighten vise more parallels should not move if seated well. Making a rectangle object Best to square up the sides first. Place part in vise cut one side, flip part over and cut other side. Lay part flat using the two fresh cut sides in the vise and use the side of the cutter to cut 3rd side. Flip part over and cut 4th side with the side of the cutter. Now sides are square and the part can be placed at correct height to cut the faces of the part. Flip part over and cut last face. ===Links=== [http://en.wikipedia.org/wiki/Milling_machine Wikipedia] af5b4f9ae22955f5f944c199595b39cbffcc38be 0 437 1025 1024 2013-05-12T02:54:29Z Jsfisher 1 1 revision wikitext text/x-wiki Flat mirrors are used in holography whenever the beam needs to be turned. For most holography there is no need for precision mirrors but it is very important the the mirror be [http://en.wikipedia.org/wiki/Optical_coating coated] with a reflection coating on the front side (Known as a "front surface" mirror). Small concave mirrors are available that can be used as a beam expander. [[Cleaning Mirrors]] ====Silvered Mirrors==== Silvered mirrors have the advantage that they are inexpensive but their damage threshold is usually low. Their reflectivity is only about 85-90% in non enhanced aluminum coatings. Silvered mirrors almost always have a protective overcoating and can also have an enhanced coating to increase the reflectivity to better than 90% in the visible range. Enhanced coatings are cost advantagous compared to buying a more powerful laser. ====Dielectric Mirrors==== Dielectric mirrors have the highest reflectivity and damage threshold available. They are more sensitive to reflection angle than silvered mirrors and are not often used at angles greater than 50 deg. Reflectivities can exceed 98%. They are created by coating the surface with coatings of alternating index of refraction at 1/2 wavelength thicknesses. The larger the difference in index of refraction and the more coatings, the higher efficiency the mirror will have. This is the mirror of choice inside of laser cavities because of their high efficiency. Damage threshold is about 100mj/cm^2. [[Cleaning Dielectric Mirrors]] ====Collimation Mirrors==== [[Image:CollimationMirror.jpg]] 10.1" f 4.5 parabolic mirror in a home made mount. Some holographers prefer collimation lenses rather than mirrors but the cost is lower for a mirror so many use a mirror. The ideal mirror is a spheroid figure. Telescopes have a paraboloid figure. Since there are many used telescope mirrors available many holographers choose to use them. Since a telescope suffers from the [[Optics Aberrations|aberration]] called coma it is best to keep the reflected angle as small as possible. =====Tips===== *A disposable shower cap makes a good cover for your collimation mirror when it is not in use. *For a collimated beam the pin hole of the spatial filter (or focal point of the expanding lens) needs to be the diameter times the focal ratio away from the mirror. For the mirror above 49.5 inches. =====Finding the Focal Point of a Collimator when f stop or focal point is unknown===== *If the f stop or the focal length of a collimator is not known, here is a way to find out where to place the pinhole to get a collimated beam. Measure the diameter of your collimator. Now draw a circle on a white piece of paper with that diameter. Place the paper about 2 or 3 meters (actually as far away as possible) away from the collimator such that the reflected raw laser beam bounces off the collimator and hits directly in the center of the circle on the paper. Now take your lens and place it in the beam prior to the collimator and close to it. Keep an eye on the spot being projected onto the paper with the circle drawn on it. Now start moving the lens away from the collimator, up stream of the laser beam while watching the spot on the paper. As you move back the beam will get bigger and bigger until there is a point where it remains the same size. Mark the distance the lens focal point is from the collimator. Now continue back until the spot becomes smaller. Mark this distance. The focal point of the collimator will be approximately in the center of these two marks. *For a final adjustment, place the lens focal point at the found focal point. Take the white paper with the circle on it and move it toward the collimator. If the spot becomes smaller the beam is diverging and the lens needs to be moved further away from the collimator. If the spot becomes larger when moving toward the collimator the beam is converging and the lens needs to be moved closer to the collimator. Repeat this procedure until the spot remains the exact same size while moving from that very far away point all the way up to very close to the collimator. When you find the focal length (which is from the focal point of the lens to the center of the collimator, write it down directly on the back or side of the collimator for future reference thus needing to do this procedure once for that mirror. *It is best to use a low power lens that allows this procedure to be carried out such that the beam is never expanded past the edge of the collimator. If, while moving the lens away from the collimator the beam expands past the edges of the collimator and the reflected spot has not yet stopped expanding, stop at this point and note the size of the reflected spot on the paper. It should be the same size or larger then the drawn circle (it is impossible that the reflected spot is smaller or the reflected spot would have already stopped expanding and would have started getting smaller). If the spot size is the same size of the circle you are at the approximate focal length. If the spot is large then the drawn circle, continue moving the lens away from the collimator unit the spot is the same size as the drawn circle and this will be your approximate focal length. At this point perform the procedure for Final Adjustment above. ====Mirrors Used for Polarization Rotation==== This image is self explanitory on how to rotate the polarization of the laser beam with two front surface steerable mirrors. This was taken directly from Kaveh's Thesis with his permission. [[Image:PolarizRotateWMirrors.jpg]] 5a43109e09e8a969d4dc16ca8dbf1b6bbc2cab8b 0 438 1027 1026 2013-05-12T02:54:29Z Jsfisher 1 1 revision wikitext text/x-wiki =====Mode Hops ===== Besides [[Equipment#Longitudinal_Modes_and_Coherence_Length|coherence length]], another important property of a laser is its stability against <b>mode hops</b>. A mode hop (or jump) refers to a sudden change of the [[Equipment#Longitudinal_Modes_and_Coherence_Length|longitudinal mode spectrum]], which typically occurs when the currently lasing mode drops out of the laser medium gain profile (eg, due to thermal expansion of the laser cavity), so that suddenly another mode at a slightly different wavelength has higher gain and so will start to lase. Its effect on a hologram is a reduced coherence length, in some respect quite similar as if several [[Equipment#Longitudinal_Modes_and_Coherence_Length|longitudinal modes]] lase simultaneously. Indeed, whether several different longitudinal modes are present simultaneously or whether they just lase one after the other, doesn't matter much: in each case interference fringes are blurred, and the severity of this effect depends on the frequency (or wavelength) difference of the involved modes (for mode hops the blurring also depends on the fraction of the exposure time during which a given mode lases; obviously a very brief hop to another mode will not matter much. In the following, we will assume for simplicity that all involved modes contribute during the same amount of time). Therefore, mode hops are much more serious for lasers with a large mode spacing or short cavities, such as [[Types_of_Lasers#Diode_Lasers|diode lasers]]. For the latter, the mode spacing is like 100Ghz, so one single mode hop during exposure time will effectively cut down the coherence length to a few mm or less -- pretty much ruining any hologram by giving it a "sliced bread" appearance. On the other hand, for a single mode [[Types_of_Lasers#Argon_Ion_Lasers |argon laser]], a mode hop effectively reduces the coherence length to roughly the length of the resonator, which does not matter for most holographic applications. Therefore, preventing mode hops is crucial for diode and other lasers with short cavities; the most common and important method is to stabilize the temperature of the laser to a fraction of a degree. The situation turns out to be even more delicate for <b>extended cavity ("ECDL")</b> designs, where an external grating is used to extend the cavity length from a mm to a few centimeters; while such constructions can do very well for atomic spectroscopy, they appear not to be too useful for holography due to stringent requirements for temperature stabilization, and a delicate setup requiring spectrum analyzing tools; see the [http://argonholo.webhop.net/laser/ECDL.html investigations here]. Related issues are smooth <b>mode drift</b> (without hops) on one extreme side, and <b>chaotic mode competition</b> on the other. If the temperature of a laser diode is slowly changed by a small amount, the cavity length smoothly changes and so does the wavelength of a given longitudinal mode. Even if no hop to another one occurs, the mere wavelength shift can also effectively reduce the coherence length and therefore must be small enough (as a rough estimate, the temperature of a laser diode must be held constant to a hundredth or even to a thousandth of a degree Celsius, during exposure time. For a more detailed discussion, see [[Types_of_Lasers#Diode_Lasers|here]]). Now, if we go on and change the temperature even further, a discrete mode hop may occur where the wavelength suddenly jumps by a larger amount; this is what we have described above. However, much worse than this can happen: in the transition zone, two (or even more) longitudinal modes can compete in such a way as to yield a chaotically fluctuating spectrum. If a diode runs in such a regime, it is totally unsuitable for any holography use! Whether hops are simple or chaotic is hard to predict, and depends on the precise operating conditions of the laser diode. For an illuminating review, see [http://www.ilxlightwave.com/appnotes/mode_hopping_semiconductor_lasers.pdf here]. <b>Detecting mode hops:</b> Simplest is to look for AC noise in the output of a photodiode via an oscilloscope, or just listen to it by coupling the photodiode to an audio amplifier. This is quite instructive and gives some idea about the behavior of your favorite diode laser. Below is a picture of the AC output of a photodiode that shows first a transition through a chaotic regime, and subsequent simple mode hops (1sec/div horizontal scale, picture taken from [http://argonholo.webhop.net/laser/diodelasers.html here]): [[Image:LDmodejumps.jpg]] b3633a414531ea858fae32b69bffa736213c060c 0 439 1029 1028 2013-05-12T02:54:29Z Jsfisher 1 1 revision wikitext text/x-wiki Mold coating is the process where you use spacers between two pieces of glass, one with a release agent, in order to get an even coating thickness. Depending on the exact chemistry desired a coating thickness is set by the spacers. A place to start is 7um. Swollen unhardened gelatin can contract on hardening by a factor of 8, but partially hardened stuff can be less than half this. #Take two identical pieces of glass. One with tape on two opposing edges. Different tape thicknesses will yield different final emulsion thicknesses. #Treat the piece of glass without the tape with Rain-X to prevent sticking. #Place a small puddle of emulsion in the center of the plate with tape on it. Make sure the emulsion does not have any air bubbles in it. With practice a known about of emulsion can be used that covers the plate but with minimal excess and overflow. #Then gently lay the piece of glass without tape and with the Rain-X (Rain-X side facing the emulsion) on top of the puddled glass as flatly as possbile. You will see the puddle of emulsion expand though th entire plate. #Place 4 black paper clamps, two on each side right over the tape. #After the gelatin has dried, minimally 3 or 4 hours, gently pull them apart. A very flat surface is left behind. ==Tips== *I would add that air bubbles in the gelatin can be removed using the edge of piece of adsorbing paper. I found bubble formation is a quite common problem when making plates. - Cristiano ===Tips from Dave Battin=== The glass I use for my mold is 1/4" mirror (back silver), while I won't call this glass optically flat, it is of optical quality. The Rain-x is the key, I put a couple drops on the mold, then buff it in, heat the mold and film plate, and meter out the emulsion. To see the emulsion do a little dance on the rain-x is really amazing! I have a "two suction cup" handle that I use to hold my plate and slowly drop/ hinge the plate along the taped edge of the mold. I then place six larger paper clamps around the perimeter My plate size is 5"x 15" and i can get 3 nice 4x5s per mold , If metered carefully (absolutely leveled mold) ,only a few drips will come off the mold ends …………. As soon as the gel sets (a few mins) I move the still slightly warm plate and mold, on to a frozen piece of granite, where it rapidly cools down. Buy the way the granite can work both ways, for both cooling, and heating! I purchased these as granite tiles a the local Depot (12"x12"), and cut them up ........ The tape I used is plain Scotch Tape and is .0025” or @ 63 microns thick. And to my surprise the film thickness came in @ .0004” or @ 10 Microns. The gelatin was Knoxx brand at a 15 grams /110 ml DI water, poured @ 70+degrees C. 7214f66546519cee8845d2bc4ce69a159faa9aed 0 440 1031 1030 2013-05-12T02:54:29Z Jsfisher 1 1 revision wikitext text/x-wiki In the illustration below the laser beam exits the laser in the upper right. It is then split by a beam splitter. Following the red path (red only for distiction and no correlation to laser wavelength) you can see it travels 3+14+15 = 32inches to the film plane. Now following each of the black paths from the first beam splitter you can see that the beam that illuminates the back of the object travels 14+2+8+8 = 32inches, as does each of the other paths 14+2+2+8+6 = 32inches and 14+2+2+2+8+4 = 32inches respectively to the film plane. The benefit of this technique is as follows. If your laser only has a coherence length of 3 inches and it can be deduced that the object is 7 inches deep and only the center object beam is used, only 3 inches of depth will be visible in the final hologram, 1 1/2 inches in front of the center of the central object beam and 1 1/2 inches in back of the center of the central laser beam. With the configuration below the front beam not only reaches to the front of the object which is only 1 inch away from the center of the front beam but also reaches 1 1/2 inches toward the back of the object at which point 1 inch back the second beam is reaching and the coherentness overlaps. Thus coherence limitations are maintained for each of the three "Volumes" of the object. The expanded reference beam is not shown for clarity. The coherence "Volume" is show with the object beams by only showing that part of the expanded object beam. [[Image:TransVolume2.JPG]] 9dba22f9dd869f0deba17b5f20223f31ac5623ec 0 441 1033 1032 2013-05-12T02:54:30Z Jsfisher 1 1 revision wikitext text/x-wiki There are many published ways to coat a surface with a Myer bar but most describe coating just a small area on the surface. Here is describe two methods for coating entire surfaces beneficial for holographic emulsion coating. ===Method 1=== This method does the best job that I have found and is depicted in the diagram below. *Take a glass size and determine what size plates you wish to coat. *Clean and sub the entire glass sheet so that it is ready to coat. In the drawing below we are doing 4 - 4inch by 5inch plates. *Make the full size glass 2 inches larger in width(1 inch on each side) and 4 inches larger in length (3 inches at top and 1 inch at bottom). *Score the glass with a glass cutter as shown but do not break any of the scores. This needs to be done on a very flat, clean and rigid surface. *Now clean the scored side from all glass chips. A wet paper towel will do nicely. TURN THE PLATE OVER. It is recommended to perform the following proceedure in 80F to 90F ambient temperature or heat the glass and rod with a warm air blower (hair dryer) unitl warm to the touch. Also, the surface should be level in both directions. *Place the Myer bar (ROD) at the top of the prescored plate. *Pour a puddle of heated emulsion across the top as shown and immediately draw the Myer bar down the length of the plate with an even pressure and speed. You will notice the puddle stay in front of the bar and continue util you are off the bottom of the plate. *Wait until the emulsion is dry (this can be tested at any four of the discard ends). *Take a razor blade and score (cut) the emulsion down each of the scores (the scores are still on the bottom and you are cutting the emulsion on the top). *TURN THE PLATE OVER and break the scores as you would with any scored glass keeping care to not let the emulsion surface touch anything. This becomes easy with practice by keeping the end your are breaking in you hand and keeping the fixed end remain on the glass cutter knob (see [[Glass Cutter|Glass Cutting]]). Break all the longest lenghts first (top, bottom, two sides then the plates). This gives very even and uniform coatings for each glass. [[Image:PreScoredCoatAtOnce2.JPG]] ===Method 2=== In the next technique, which can be modified for more plates, we will coat 4 - 4inch by 5inch plates. *Take the 4 cleaned glass plates and place them in a rectanglur fashion such that the rectangle is 8 inches across and 10inches down on a level surface. *Now take two additional cleaned 4x5 plates (puddle plates) and lay then such that they are 10 inches across at the top of the rectangle. They will overhang the rectangle 1 inch on each side. *Now use thin clear gift tape (Scotch brand works well) to tape aound the rectangle of plates (not the top two, they will be used to pour the puddle onto) and where each plate meet another plate. Each of the four plates will have tape around all four of their sides. Make sure the tape is flattened nicely to the plate with your finger. Again use the same temperature restraints as described above (ambient or blow heater). *Place the Myer bar at the top of the puddle plates. *Pour the heated emulsion across the center of the top two puddle plates and immediately draw the Myer bar down the plates and off the end of the plate as described above. *Let the plates set for only one hour, then remove the tape. Allow the plates to continue to dry lying horizontally. This too yields very consistant results. This method uses the tape for some of the emulsion thickness (the Myer bar is off the glass by the thickness of tape) so the Myer bar should be finer the in the above proceedure. Notes: *Plate, emulsion and Myer bar temperatures affect coating thickness to a small extent but if the temperature is too low on any of these, gelation may occure and quality compromised. *Myer bars come in different gauges which is the thickness of the wire that is wound. Usually a #40 is .04", a #25 is a .025 inch etc.. I have found a #25 to #40 works very well in either case with the #40 producing thicker emulsion. *Myer bars should be soaked immediately in warm water to keep the gelatin from hardening on the bar, then washed with hot water and dried. Myer Bar Selection - [http://www.rdspecialties.com/Page.asp?Script=14] 6cddf260026a49c1d3c60646c6ebed02bd9e95f8 0 442 1035 1034 2013-05-12T02:54:30Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Nadar''' - the name adopted by the first aerial photographer, G. F. Tournachon, who took photographs from an air balloon. *'''Nanometer''' - a unit of measurement of light wavelength. A nanometer is one millionth of a millimeter. (1/1000 micron; 10 angstroms). *'''Naphtha''' - a volatile petroleum based solvent such as benzine or gasoline (but not kerosene). *'''ND''' - an abbreviation for neutral density. *'''Near ultraviolet''' - wavelengths from about 400nm down to 250nm. Most photographic emulsions are sensitive to this range of bands. *'''Negative''' - the image produced on a photographic emulsion by the product of exposure and development, in which tones are reversed so that highlights appear dark and shadows appear light. *'''Negative carrier''' - supports the negative between the light source and the enlarging lens of an enlarger. *'''Neutral density''' - a technique which makes possible shorter printing times in color printing. *'''Neutral density filter''' - a gray camera filter which has an equal opacity to all the colors of the spectrum and so does not affect the colors in the final image. It is used to reduce the amount of light entering the camera when aperture or shutter settings must remain constant. *'''Neutral filtration''' - in color printing is the filtration at which color balance is achieved, rendering a neutral gray ion the film image as a neutral gray on the photographic paper. *'''New Objectivity''' - an approach to the subject matter of photography originating in Germany in the 1920s. The photographer remains an impartial observer, intensifying the appreciation of forms and structures in ordinary things but de-personalizing his/her approach. *'''New Realism''' - an alternative name for New Objectivity. *'''Newton's rings''' - rings of colored light produced when two glass or transparent surfaces are in partial contact. *'''Nitrate base''' - an early flexible film support which was highly inflammable. *'''Nitric acid''' - used in emulsion manufacture, in toners, and in bleaches, it is highly corrosive. *'''Nodal plane''' - an imaginary line passing through the nodal point, perpendicular to the optical axis. *'''Nodal points''' - located in two areas in a compound lens system. The front nodal point is where rays of light entering the lens appear to aim. The rear nodal point is where the rays of light appear to have come from, after passing through the lens. Nodal points are used to calculate optical measurements. *'''Non-silver processes''' - image making processes that do not require the use of metallic silver, such as Gum bichromate. *'''Non-substantive''' - a name given to color film in which the color couplers are not contained within the emulsion, but are introduced during processing. *'''Notch''' - a V or U shaped cut into one edge of sheet film. It denotes the location of the sensitive side of the film as well as identifying the type of film. 15e583db5653b446d87dde8ee1c9c525a3349621 0 443 1037 1036 2013-05-12T02:54:30Z Jsfisher 1 1 revision wikitext text/x-wiki Nd:Glass is a large family of materials. The properties of one of them is listed so far. ===Q-246=== Silicate Nd:Glass *Wavelength 1063nm *Cross Section 2.9x10^-20cm^2 *Flourescent Lifetime 330 u sec *Linewidth FWHM 27.7nm *Loss .002%-cm^-1 *Index of Refraction 1.572 *Index of Refraction @ 1063nm 1.561 *Nonlinear Index 1.4 N2 (10^-14 esu) *dn/dt 2.9 (10^-6/deg C) *Thermal Expansion 96 x 10 ^-7/ deg C *Thermal Conductivity .82 W/m*K *Specific Heat .80 J/g*K *Density 3.206 g/cc *Hardness (Knoop) 558 *Young's Modulus 7150 Kg/mm^2 *Poission's Ratio .24 *Damage Threshold >25 J/cm^2 (1ns) aa5f2359a1f7d27ac3160ccd400788f593adb517 0 444 1039 1038 2013-05-12T02:54:30Z Jsfisher 1 1 revision wikitext text/x-wiki ==YAG Physical and Chemical Properties== *Formula: Y3AI5O12 *Molecular Weight: 596.7 *Crystal Structure: Cubic *Moh Hardness: 8 - 8.5 *Melting Point: 1950°C (3540°F) *Density: 4.55 g / cm-3 *Refractive Index of YAG at 25C and 1.0 (µm)= 1.8197 ==Properties of Nd:YAG at 25°C (at 1.0% Nd)== *Formula: Y2.97Nd0.03AI5O12 *Weight % Nd: 0.725 *Nd Atoms / cm3: 1.38 x 1020 *Wavelength: 1.064 mm *Transition: 4F3/2 — 4I11/2 *Fluorescent Lifetime: 230 µsec *Thermal Conductivity: 0.14 W cm-1 K-1 *Specific Heat: 0.59 Jg-1 K-1 *Thermal Expansion: 6.9 x 10-6°C-1 *dn / dt: 7.3 x 10-6°C-1 *Young’s Modulus: 3.17 x 104 Kg / mm-2 *Poisson Ratio: 0.25 *Thermal Shock Resistance: 790 Wm-1 ==Room Temperature Transitions== *1.052um 46% *1.062um 92% *1.064um 100% *1.065um 50% *1.074um 65% *1.078um 34% *1.105um 9% *1.112um 49% *1.116um 46% *1.123um 40% *1.319um 34% The precentage shown are relative to 1.064nm. ==Main Absorbtion Peaks== *590nm *750nm to 770nm *790nm to 820nm cae49e0a91786842846bfd29f48b564556bbaed6 0 445 1041 1040 2013-05-12T02:54:31Z Jsfisher 1 1 revision wikitext text/x-wiki ==ND:YVO4 - Vandate== *Lasing Wavelengths : 914nm, 1064nm, 1342nm *Refractive Indices: @1064nm 1.9573(no) 2.1652(ne) *@808nm 1.9721(no) 2.1858(ne) *@532nm 2.0210(no) 2.2560(ne) *Absorption Coefficient: ~31.4%/cm @808nm *Absorption Length: 0.32mm @808nm *Stimulated Emission Cross-Section: 2.50x10-18 cm2 @1064nm *Fluorescent Lifetime: 90 µs (about 50 µs for 2 atm% Nd doped) @ 808nm *Intrinsic Loss: 0.02/cm @ 1064nm *Gain Bandwith: 0.96nm (257 GHz) @ 1064nm *Polarized Laser Emission: p polarization;parallel to optic axis (c-axis) *Diode Pumped Optical to Optical Efficiency: >60% ===Physical Properties:=== *Crystal Structure: Zircon Tetragonal, space group D4h *Cell Parameters: a=b=7.12Å, c=6.29Å *Mohs Hardness: »5 *Density: 4.22g/cm3 *Hygroscopic Susceptibility no *Thermal Conductivity(W/cm·K): parallel to c: 0.0523; vertical to c: 0.0510 *Thermal Expansion Coefficient: parallel to a: 4.43x10-6; parallel to c: 11.37x10-6 36508e66cbf4ed350f686a4a2d3ca589e63b5f90 0 446 1043 1042 2013-05-12T02:54:31Z Jsfisher 1 1 revision wikitext text/x-wiki A '''neutral density filter''' or '''ND filter''' is a "grey" filter. An ideal neutral density filter reduces light of all wavelengths or colors equally. ND filters that are created by being partially reflective are often used in holography as a [[Beam Splitter]]. For an ND filter with 'OD' the amount of optical power transmitted through the filter is given by: Fractional Transmittance = 10^-OD In a graduated ND filter the intensity varies across the surface of the filter. Practical ND filters are not perfect as they do not reduce the intensity of all wavelengths equally. Most ND filters are only specified over the Visible spectrum region of the spectrum, and do not proportionally block all wavelengths of ultraviolet or infrared radiation. ND filters find applications in several high-precision laser experiments. This is because the power of a laser cannot be adjusted without changing other properties of the laser light](e.g collimation of the beam). Moreover, most lasers have a minimum power setting at which they can be operated. To achieve the desired light attenuation, one or more neutral density filters can be placed in the path of the beam. ND filters are quantified by their optical density or equivalently their f-Stop reduction as follows: {| border="1" cellspacing="0" cellpadding="5" align="center" ! Attenuation Factor ! Filter Optical Density ! f-Stop Reduction ! % transmittance |- | 2 | 0.3 | 1 | 50% |- | 4 | 0.6 | 2 | 25% |- | 8 | 0.9 | 3 | 12.5% |- | 64 | 1.8 | 6 | 1.5625% |- | 1,000 | 3.0 | 10 | <0.1% |- | 10,000 | 4.0 | 13 | <.01% |- | 1,000,000 | 6.0 | 20 | <.0001% |- |} Another practical way of determining what type of ND filter to use is by the percent of light that the filter allows to pass (transmittance). This parameter is typically applied to microscopy applications versus photography applications. Here is a more complete list of Filter Optical Density versus percent light transmitted: [http://www.chroma.com/images/noSpectra/22000a.gif] 7415c5480133dcd4b09349343092e0387605cb77 0 447 1045 1044 2013-05-12T02:54:31Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Off the film metering''' - a meter which determines exposure by reading light reflected from the film during exposure. Pioneered by Olympus on its OM2n. Most flash modes have OTF. *'''Oil reinforcement''' - a method of altering the tonal range of prints on matte or textured fiber papers. The dried print is rubbed with a medium consisting of two parts of turpentine to one of mastic varnish and one of linseed oil. Artists oil color is then applied locally to the print. *'''One shot color camera''' - an obsolete plate camera making three color separation negatives from a single exposure. *'''One shot developer''' - a developer that is used on a single occasion and then discarded. *'''Opacity''' - the light stopping power of a a material. The greater the opacity of a substance, the more light its stops. In photography, opacity is expressed as a ration of the amount of light falling on the surface of the material to the amount of light transmitted by it. *'''Opalescent''' - like opal, a material with a cloudy-white translucent appearance. *'''Opal lamp''' - a filament lamp with an opal glass bulb for optimum diffusion. *'''Opalotype''' - an obsolete printing process in which a carbon-process image is transferred on to translucent opal glass. *'''Opaque liquid''' - a dense red or black pigment, dissolved in water to form a liquid paint used to fill in film areas that are required to pint as pure white. *'''Optical axis''' - an imaginary line passing horizontally through the center of a compound lens system. *'''Optical bench''' - a device for measuring the optical performance of lenses. Holographers usually use horizontal planes called ‘tables’. *'''Optical glass''' - used for manufacturing lenses and prisms. It is specially manufactured to be free of defects and distortion, and to withstand heat and humidity. Each type f optical glass is classified according to its refractive index and light dispersive quality. Two or more types of optical glass are typically used in the component elements of photographic lenses. *'''Optical sensitizing''' - a method of increasing a films sensitivity by the use of dyes. *'''Optical wedge''' - a strip of material, clear at one end and gradually increasing in opacity, which is used to determine the effect of light intensities on sensitized materials. *'''Optics''' - the science dealing with the behavior of light. *'''Ordinary emulsion''' - a term applied to a photographic emulsion which is only sensitive to ultra-violet and blue light. *'''Orth-phenylene diamene''' - a fine-grain developing agent. *'''Orthochromatic''' - used to describe an emulsion which is sensitive to blue and green light, but insensitive to red. *'''Over-development''' - a term indicating that the amount of development recommended by the manufacturer has been exceeded. It can be caused by prolonged development time or an increase in development temperature, and usually results in an increase in density and contrast. *'''Over-exposure''' - an expression used to indicate that the light sensitive material has been excessively exposed. *'''Oxalic acid''' - soluble white crystals used in some toners. *'''Oxidation product''' - the chemical produced by a color developer during the conversion of exposed silver halides to black metallic silver. 55a371f78711c9eea77aece159b86dddf9495a22 0 448 1047 1046 2013-05-12T02:54:32Z Jsfisher 1 1 revision wikitext text/x-wiki Stability is very important to holography. In order to hold the relative alignments of the optics the table must be stiff. It also must be isolated from vibrations coming from the ground and air. To learn about table design see [[Table Design Theory ]]. To see pictures of lab's set up for making holograms see a [[Tour of Holography Labs]]. ====Pavers==== Pavers make a great table if you only need to have a 1' x 1' table. There many setups that can be made on a small table. See [[Laser Pointer Holography]] for examples. ====Concrete Tables==== Concrete tables are inexpensive easy to fabricate and very stiff. This comes at the price of weight. The weight helps to isolate the table from vibrations coming from the ground. Many sucessful tables have been made 4'x8'x3.5" thick. ====Sand Tables==== Sand tables are the easiest to use, cheapest to make and most versatile tables available. They have made more holograms than any other home built table. When building a sand table it is important to use dust free sand. The kind sold for ash trays works well. Lon Moore's last table was 4x8' of 3.5" thick concrete with brick and mortor side walls enclosing sand 2' deep. It was extremely versatile and stable. Making optic mounts for a sand table is extremely quick and easy. Most people use PVC tubing fashioned with hand tools. ====Concrete Block Tables==== by Bob Hess I've described my 4x8' tables made of cinder blocks with steel plate and breadboard tops here in the past, floating on three or four inner tubes (from fork lift tires) or on tennis balls (an idea I got from Ken Haines). They all work fine if you can live with the excentricities of each type. I always rubbed the burrs off the cinder blocks before building the tables to decrease their stress when cinched together, and made the top of the blocks as flat as possible to minimize the thickness of filler material between them and the top. Lay a piece of plastic film between the filler material and the top so you don't stick the top to the blocks for easier disassembly. I never used hexcel because the skin is too thin to adequately support heavy loads locally (in my opinion). A 4x8' optical breadboard with the threaded holes is best for a top as it's 3/16" skin is locally rigid, the surface is flat, and it can be moved by two men with piano dollies. I like laying the cinder blocks out interlaced like a wall on its side, and running the threaded rods parallel to the short dimension of the table to minimize their length. [[Image:ConcreteBlock1.jpg]] I thought I'd post some pics of old tables I described earlier in this thread. The one on the right above is the first I built in a bedroom of my apartment in East Palo Alto in 1982. The rods that squeeze the blocks together are running lengthwise in it and the the other as well. The table on the left has a steel top 3/16" thick, with cement patching material between it and the block surface. The bedroom window was covered with cardboard and black plastic. The lasers were in the other bedroom with their beams going through shuttered holes in the wall. I was on the ground floor slab in the corner of a three floor apartment building, and routinely did exposures up to around five minutes if I remember correctly with a 30mW HeNe laser. The pic below shows the table I built in 2003 in a metal sculptor's studio in San Jose. The rods run across the table instead of lengthwise, and I used three legs instead of four. Same 4x8' Newport breadboard, which is now on its edge in the garage until I fix the garage. I fully supported the plywood base while laying out the cinder blocks to make them as flat as I could before squeezing them together. [[Image:ConcreteBlock2.jpg]] ====Commercial Tables==== Commercial Tables are the stiffest most versatile tables available. They come with tuned legs or active dampening. While there are by far the best they are also the most expensive. [http://www.newport.com/Table-Specifications/140219/1033/catalog.aspx Newport] is one of the premiere manufactures. 57b08a1b9b26f28d54ca915071df5bb1cdc88bf2 0 449 1049 1048 2013-05-12T02:54:32Z Jsfisher 1 1 revision wikitext text/x-wiki ====Gravity Optic Mounts==== ====Magnetic Optic Mounts==== ====Optic mounts for Sand Tables==== ====Simple Optic Mounts==== 90359aa1671810dbd0c305271e0dd44cb6cf4f37 0 450 1051 1050 2013-05-12T02:54:32Z Jsfisher 1 1 revision wikitext text/x-wiki =Spherical= Parabolic mirrors can focus light tightly, a spherical mirror produces aberrations particularly along the outer edge. =Coma= Coma is most often encountered in holography when a parabolic collimation mirror is used off-axis. =Astigmatism= When the lens is more oblong than it is spherical. It's also the most common vision problem with the human eye. =Chromatic= If a lens diffracts differnt colors in different ways, then you get chromatic abberation. The classical example is a prism that breaks white light into a rainbow of its components (ROYGBIV). Mirrors are imune from chromatic aberrations. [http://en.wikipedia.org/wiki/Aberration_in_optical_systems Wikipedia's Aberration Section] aeb2c81f568ff2554e3593bffa95bda3adeee00f 0 451 1053 1052 2013-05-12T02:54:32Z Jsfisher 1 1 revision wikitext text/x-wiki ==Lens Equations== ==Ray Tracing== ==Images== ===Real Images=== ===Imaginary Images=== ===Orthoscopic Images=== ===Psuedoscopic Images=== ==Spatial Filter Theory== [[Optics_Aberrations]] 4a91fbae222d8b3816f9dc561185a263b927301c 0 452 1055 1054 2013-05-12T02:54:33Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Painting with light''' - technique of lighting large, dark interior. The camera, mounted on a tripod, is given a long time exposure. The photographers moves continuously around the interior, giving flash or battery powered photoflood illumination to the shadow areas. *'''Panchromatic''' - photographic emulsion sensitive to all the colors of the visible spectrum and to a certain amount of ultra-violet light. The sensitivity is not uniform throughout the spectrum. *'''Panchromatic vision filter''' - filter through which the subject can be viewed approximately as it would appear in monochrome as recorded by a panchromatic emulsion. *'''Panning''' - technique of photographing moving subjects. While the shutter is open, the camera is swung in the same direction as the subject is moving. This creates a blurred background, but a sharp subject. *'''Panorama''' - picture presenting a continuous view of the landscape, produced either by using a panoramic camera or from a composite of several images. *'''Panoramic camera''' - camera with a special type of scanning lens which rotates on its rear nodal point and produces an image of the scanned area on a curved plate or film. *'''Parallax''' - difference between the image seen by a viewing system and that recorded on film. Only TTL viewing systems avoid parallax error. *'''Paraphenylenediamine''' - reducing agent used in some fine grain and color developers. *'''Paraphotography''' - general term for non-silver-halide image forming processes. *'''Paraxial''' - rays nearest the optical axis of a lens. *'''Patch chart''' - squared pattern test strip often made when color printing by the additive method. *'''Pellicle''' (pellicule) - thin film used in one-shot color cameras as a semi-reflecting surface. *'''Percentage solution''' - solution containing a given quantity of a dissolved substance in a stated volume of solvent. *'''Perforations''' - accurately spaced holes punched throughout the length of film for still cameras. Basically the perforation function as a guide for precision registration of film and also provide mechanical movement from frame to frame. *'''Periphery photography''' - technique used to photograph the entire inner or outer surface of a cylinder or tube. *'''Permanence tests''' - methods of establishing whether long term permanence of an image has been achieved. *'''Perspective''' - relationship of size and shape of three-dimensional objects represented in two-dimensional space. *'''pH scale''' - numerical system running from 0-14 and used to express the alkalinity or acidity of a chemical solution. 7 is neutral. Solutions with a lower pH value are increasingly acidic, and those with a higher pH value are increasingly alkaline *'''Phenidone''' - reducing agent used in many fine grain solutions. *'''Phenol varnish''' - resin used to produce a hard durable top coating. *'''Phosphorescence''' - property held by some materials of absorbing light of one wavelength and emitting it as light of a different wavelength. *'''Phosphotophotography''' - technique of projecting an infrared image on a phosphorescent surface. *'''Photo color transfer''' - method of making color enlargements by exposing on full size sheet film which is then soaked in a activator solution and rolled in face contact with receiving paper. The sandwich is then left in normal light for 6-8 minutes and peeled apart to give a finished print. *'''Photo elasticity''' - method of determining stress patterns in structures with the aid of polarized light. *'''Photo-electric cell''' - light sensitive cell. Two types are used in exposure meters. A selenium cell generates electricity in proportion to the amount of light falling upon its surface. A cadmium sulfide cell offers a resistance to a small electric charge when light falls upon it. Cadmium sulfide cells are more sensitive then selenium, especially at low light levels. *'''Photo-engraving''' - production of a relief printing surface by chemical or mechanical means, with the aid of photography. *'''Photo-etching''' - technique of contact printing an image on lith film on a presensitized zinc plate which is then processed and chemically etched to give a relief image. *'''Photogenic drawing''' - original name given by William Fox Talbot to his earliest method of recording camera images. *'''Photogram''' - pattern or design produced by placing opaque or transparent objects on top of a sensitive emulsion, exposing it to light and then developing it. *'''Photogrammetry''' - method of making precise measurements from photographs. *'''Photography''' - literally writing or drawing with light (from the Greek words photos meaning light and graphos, writing). First suggested by Sir John Herschel to William Fox Talbot in 1839. *'''Photogravure''' - method of printing photographs from an etched copper plate. *'''Photolinen''' - laminate of linen and paper coated with black and white photographic emulsion. It is used for photographic wall coverings. *'''Photolithography''' - lithographic printing process using an image formed by photographic means. *'''Photometer''' - instrument for measuring light being reflected from a surface. It works by comparing the reflected light with a standard source produced within the photometer. *'''Photomicrography''' - system of producing larger than life photographs by attaching a camera to a microscope. *'''Photon''' - particle of light energy. It is the smallest quantity of radiant energy that can be transmitted between two systems. *'''Photo-reportage''' - use of photographs in newspapers and magazines, to supplement or replace written journalistic accounts. *'''Photo-resistor''' - photoelectric cell which varies in its electrical resistance according to the light received. *'''Photo-silkscreening''' - method of silkscreening images, using a stencil produced photographically. *'''Photo telegraphy''' - transmission of pictures between two points by means of radio or telegraph. A print is wrapped around a cylinder and scanned by a small spot of light. Reflected light values are transmitted as a stream of signals. They control an exposing light source at the receiving station, which exposes light sensitive material on a similar drum. *'''Photo-transistor''' - light sensitive electronic component which functions as a switch. Used for slave firing of electronic flash heads. *'''pH scale''' - numerical system running from 0-14 and used to express the alkalinity or acidity of a chemical solution. 7 is neutral. Solutions with a lower pH value are increasingly acidic, and those with a higher pH value are increasingly alkaline *'''Physical development''' - system of development in which silver is contained in suspension within the developer and is attracted to the emulsion by silver halides which have received exposure. *'''Physiogram''' - photographic patter produced by moving a regulated point of light over a sensitive emulsion. *'''Pictorialist''' - photographs which are a picturesque, decorative art in their own right and appeal to the viewers sense of beauty. *'''Piezo-electric flash''' - tiny flash bulbs (normally housed in flash cubes) which can be fired by a very low current produced by striking a piezo-electric crystal. Such bulbs can therefore be used without a battery. *'''Pigment''' - coloring material that is insoluble in the liquid carrier with which it is mixed. Examples include paint or poster color. *'''Pigment processes''' - making a positive print by using the property of bichromated colloids by changing their physical characteristics with exposed light. Gum bichromate is a pigmented process. *'''Pinacryptol''' - yellow and green dye powders which are used in desensitizing solutions. *'''Pincushion distortion''' - lens aberration causing parallel, straight lines at the edge of the image to curve toward the lens axis. *'''Pinhole camera''' - camera without a lens which uses a very small hole pierced in one end to allow light to pass through and form an image on the back of the camera which can be covered by film. *'''Pixels''' - abbreviation for picture elements. The tiny squares of light making up the picture are transmitted in digital form and reconstituted as a visual image. *'''Plane''' - imaginary straight line on which image points may lie or which passes at right angles through a set of points perpendicular to the optical axis. *'''Plates''' - early photographic glass plates coated with emulsion. *'''Plate camera''' - camera designed to take glass plates but often adapted to take cut film. *'''Platinotype''' - obsolete contact printing process popular among pictorialists. *'''Point source lamp''' - arc type lamp producing light from a small gap between two carbon rods. *'''Polarization''' - light said to travel in a a wave motion along a straight path, vibrating in all directions. Polarization can be brought about with a polarizing filter which causes light to vibrate in a single plane only. Polarizing filters are used over camera lenses and light sources to reduce or remove specular reflection from the surface of objects. *'''Polarized light''' - rays of light that have been restricted to vibrate in one plane only. *'''Polarizing filter''' - colorless gray filter made from stressed glass. Polarizing filters are used over light sources or camera lenses to reduce or remove specular reflection from certain types of surfaces. *'''Pola-screen''' - another term for a polarizing filter. *'''Portrait lens''' - lenses produced specifically for portraiture. They usually have a long focal length and produce a slightly diffused image. *'''Potassium bromide''' - chemical used as a restrainer in most developing solutions and as a rehalogenizing agent in bleaches. *'''Potassium carbonate''' - highly soluble alkaline accelerator used in most general purpose and print developing solutions. *'''Potassium chloride''' - chemical used in some bleaches and sensitizers. *'''Potassium citrate''' - chemical used in blue and green toners. *'''Potassium ferricyanide''' - chemical used in Farmer's reducer as a bleach. *'''Potassium hydroxide''' - caustic potash. Highly active alkali, used as the basis for high contrast developing solutions. *'''Potassium iodide''' - chemical used in bleaches, toners and intensifiers. *'''Potassium metabisulfite''' - acidifier used in fixers and stop baths. *'''Potassium permanganate''' - chemical used extensively in reducers, bleaches and toners. *'''Potassium persulfate''' - chemical sometimes used in super-proportional reducers. *'''Potassium sulfide''' - chemical used in sulfide toning. *'''Potassium thiocyanate''' - chemical used in some fine grain developers as a silver solvent. *'''Positive''' - in photography, the production of prints or transparencies in which light and dark correspond to the tonal range of the original subject. *'''Posterization''' - photographic technique using a number of tone separated negatives which are printed on high contrast material. A master negative is made by printing these in register. The final print from this contains selected areas of flat tone in place of continuous tone. Sometimes incorrectly referred to as solarization. *'''Potassium Dichromate''' - sensitizer use to make Dichromated Holograms and also use in some Silver Halide Bleaches. *'''Prehardener''' - chemical solution used to harden the gelatin of an emulsion prior to processing. *'''Preservative''' - chemical, commonly sodium sulfite, used in developing solutions to prevent rapid oxidation of the reducing agents in use. *'''Preset focus shooting''' - technique in which focus is set at a predetermined setting and the shutter is released when the subject moves into the focus point. *'''Pre-soak''' - preparatory water bath for film or paper prior to processing that prevents uneven development. It is essential in some color processes. *'''Principal axis''' - imaginary line which passes through the center of curvature of all the lens elements. *'''Principal planes''' - imaginary lines which pass through the nodal planes of a lens system. *'''Principal point''' - point from which the focal length is measured. The principal point of a simple lens is located at the center of the lens. Compound lenses have two principal points, the location of which cannot be determined by appearance. *'''Processing''' - sequence of steps whereby a latent photographic image is converted into a visible, permanent image. *'''Projection cutting''' - any method of printing in which the image is optically projected on the sensitized material. *'''Projector''' - apparatus used to display enlarged still or moving images on to a screen. *'''Protective toning''' - toning process used to protect black and white prints from fading and give archival permanence. Usually used selenium or gold toners. *'''Pulling''' - method of underrating the normal ISO speed of a film to produce an overexposed latent image. *'''Pushing''' - method of overrating the normal ISO speed of a film to produce an underexposed latent image. Used to increase the working speed of a film. *'''Push processing''' - increasing the development time of a film to increase its effective speed. See Pushing. 9056b84e333387f2f5e34acc93d192ce0cf4080b 0 453 1057 1056 2013-05-12T02:54:33Z Jsfisher 1 1 revision wikitext text/x-wiki Painting the back of a hologram black is a great way to enhance the contrast of the image. Care must be taken to not destroy the image while painting it. (Do not try this before sealing DCG holograms!) ===Tips=== *Paints that dry too quickly can damage some emulsions by shrinking them and making a crazed glass pattern. *Krylon Ultra flat black can dry very quickly if not applied in very thin coats. *Krylon gloss and flat seem to work well. *Make sure to protect the front of the hologram while painting. *Paint the edges if you are not going to frame the hologram to keep stray light from entering. *More thin coats is better than one thick coat. *Don't try to rush the drying. *Examine the hologram from the front after painting with a light source behind it to look for any thin spots. 4e065bda67229d7022fa49e7b87ee6dbf8118e68 0 454 1059 1058 2013-05-12T02:54:33Z Jsfisher 1 1 revision wikitext text/x-wiki The minimum coherence length needed for holography is the twice depth of the scene unless [[Multiple Coherence Volumes]] are used. In order to preserve your coherence length you need to make sure the distance from the laser to the film is with in the coherence length of your laser. This is extremely important with inexpensive HeNe lasers with a coherence length of only a few inches and not so important on lasers that have 50M or so of coherence length like the Coherent C315. In a complicated set up you can end up with 5 or more laser beams. Every one of the beams needs to be traced and measured. There two methods in common use. ===Method 1=== The easiest way is to use a piece of string. Since the distance from the laser to the first beam splitter is the same for all paths we can start our measurements from the first beam spliter. Hold the end of the string against the beam splitter mount at a place that is the same distance as the reflective surface. Then hold the string to the next mirror or optic and keep your finger on that place of the string. Then starting where your finger was on the string continue down it to the next optic or plate and mark this on the string. Continue this until you reach the film plane. Now, mark film plane intersection on the string with a piece of tape (the edge facing the starting end of the sting). This is your path length. Now repeat the same for the second beam path again starting at the beam splitter. Adjust one of the optics to gain or lose distance such that both path lengths are the same. Do this for all paths from the beam splitter. If a second beam splitter is used then each path from that splitter needs to be matched but independenly of the total length from the first beam splitter as stated above the path to the second beam spliter will be the same for each of the split beams. This method may require two people depending on geometry and table size. This is a little confusing, it is important to make sure that when going to the second beamsplitter thet the first path measured not be shifted. It is only the unmeasured path that needs to be changed. I'll think of how to reword it... ====Tips==== *Use a rigid string and not a stretchy one like nylon. Test the string by holding one end the pull it just taught against a wall or table. Then add additional pulling tension. If the string stretches easily and continuously DO NOT USE IT. If it does seem to stretch a little but then a lot of force is needed to stretch it more, it can be used and note the pressure needed to get past the original stretchyness of the string. You will need this pressure when using it on the holographic table. *A piece of fishing thin wire and most fishing lines do not have stretch are are preferable. *'''Make sure to include the distance from the object to the film for object beams!''' * Unless your laser is single longitudinal mode, you want to make sure your path length is even multiples of 2L where L is the length of between resonator mirrors in your laser. So for a HeNe that is 12 inches long you want to make sure the path length is either 24,48,etc multiples of 24 inches. Odd multiples is where the beam intensity will be it's lowest. * In Pulse lasers don't forget it's the distance from the oscillator so you need to know the laser's internal path length as well. * Finally don't forget about polarization. If you use a standard optical table mounted setup with mirrors all the same height as the object then a vertical polarized laser orientation gives a brighter image than a horizontal one. ===Method 2=== Another method it to use a carpenters retractable rule, the metal kind that roll up into a casing (Tape Measure). Most of these rules are designed with a curve such that you can be at the casing end of the rule, pull it out and hold it at just the casing end and the extended end will support its own weight and remain rigid. Thus using this method has two benefits. One, longer lengths can be done by just one person. Second, there is no error of trying to hold the string and mark it with one hand and keep the mark for the next set of optics. *Simply extend the rule from the beam splitter to just past the first optic. *Then hold the rule such that the extended end is at the optic surface then measure to the beam splitter surface. *Write down the length. *Do this for each segment until the film plane. *Add up the lenghts and that will give you a final length from the beam splitter to the emulsion surface. *Then do the same for each beam after the beam splitter. But the disadvantage is as follows. Say that you have a beam splitter then one mirror in each path and then the film. With the string simply find the length from beam splitter, to mirror to film and mark the string. Now with the second path simply hold the end of the string at the beam splitter and the marked end at the film and pull the center of the string out so that it makes a "V" this is where you can place the second transfer mirror. The rigigidity of the tape make this difficult. It may be advantageous to use the string to get approximate optic placements, then use the tape method to be more precise. ====Tips==== *'''Be careful not to scratch the optics!''' *The wider the tape, the longer distance it can remain unsupported. ===Example Diagram=== In the following diagram you can see that each path (green, red and blue) are all equal to one another starting at the first beam splitter. It is important, especially if your coherence length is low, to be precise in your measurements. Measure from the exact plane of the emulsion (in this example the emulsion is on one side of a glass plate), from the reflection side of the beam splitter for both beams and from the center of the depth of the object. [[Image:TransSetUp.JPG]] '''Split Beam Reflection Diagram.''' Note: All of the beams are of one color and from one laser. The different colors are shown to represend different path lengths. '''Red''' Object beam 1. *4.5+4+4.25+3.5+1.25=17.5 '''Green''' Reference beam. *1.5+5+5+6=17.5 '''Blue''' Object beam 2. *4.5+4+4.25+3.5+1.25=17.5 Note: Using this method (using center of object) the coherence length of your laser will very nearly dictate the depth of your object. 340f51f2fae2f1de83a1b18b1e73b884dd2243d5 0 455 1061 1060 2013-05-12T02:54:34Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Pchristie.jpg]] [http://www.litiholographics.com Liti Holographics] Company founder, President and Chief Technology Officer Mr. Christie has extensive knowledge and experience in developing optical systems. Prior to completing graduate work in holographic & three-dimensional display technology at MIT, one of the world’s leading media labs, Mr. Christie was responsible for inventing several new technologies for improving LCD projection displays for Projectavision, Inc., one of which was patented. His Masters Degree work is also currently being patented by MIT. He subsequently formed the predecessor company to Liti Holographics in December of 1997. He holds a Bachelor's degree in Applied Physics from Columbia University and a Master's degree in Media Technology from MIT. 5a55966785e353be7412e05b6f4cac2af30114d6 0 456 1063 1062 2013-05-12T02:54:34Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Barefoot.jpg]] == ''Paul D. Barefoot'' == ''President:Holophile, Inc.'' Paul Barefoot saw his first hologram in New York at the International Center of Photography exhibition, ''Holography '75: The First Decade'', produced by Jody Burns and Posy Jackson. It was there that he caught "Holography Fever." Within months, he moved to New York from his hometown of Charlotte, NC, where he was Director of Marketing for a graphic arts company and a C130 pilot with the North Carolina National Guard. In November, 1975 he founded Holophile, Inc. to market holography to corporations and nonprofit clients. He also began an affiliation with John Bliss Associates, Inc. (later, Bliss, Barefoot & Associates, Inc.), who served as Public Relations counsel to the Museum of Holography from its inception in 1976. In 1977, Barefoot worked with Museum of Holography founder, Rosemary Jackson, to organize a traveling exhibition of the Museum's inaugural exhibition, ''Through the Looking Glass''. It opened in Toronto and traveled to art, science and children's museums throughout the U.S. Public response was overwhelmingly positive.The exhibition was booked with institutions continuously for ten years -- not returning to New York until its retirement in 1987. During that time, Barefoot took ''Looking Glass'' to Australia for an appearance at the Adelaide Festival of Arts, and to Jerusalem where it broke the all-time attendance record at the Israel Museum In1988, Barefoot began circulating the Museum's second traveling exhibition, ''FutureSight: Innovations in Art Holography''. This exhibition, curated by Rene Barilleaux, traveled to art museums and galleries in the U.S., plus a tour of four New Zealand museums in Auckland, Wellington, Christchurch and Dunedin. In 1992, Barefoot organized a new traveling exhibition entitled, ''The Nature of Holography''. A second show (of the same name) was developed in 1993 to meet the growing demand by art, science, and children's museums. A third exhibition, ''Holography: Making Faces'', was introduced in 2007. These exhibitions, which feature images from the Holophile Collection, are still in circulation. (See complete listing of host institutions since 1977 [http://www.holophile.com/html/exhibit.htm]) Since founding Holophile in 1975, Barefoot has worked as a producer of custom holograms for use by corporate, not-for-profit and government clients, including The American Gas Association, BP Oil de Venezuela S.A., Canary Islands Tourism Board, The Coca Cola Company, IBM, National Security Agency (NSA), M & T Chemicals, Inc., PricewaterhouseCoopers, Samsung Electronics, Pfizer Pharmaceuticals, Raytheon Canada, Ltd and The Weizmann Institute of Science. Barefoot continues to work in holography and other three-dimensional imaging technologies through his company, Holophile, Inc. ([http://www.holophile.com]), located in Killingworth, CT. e3695ac1ee3b828098db5f06e1b85e20e4577af6 0 457 1065 1064 2013-05-12T02:54:34Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.pearljohn.co.uk/holography.html Pearl John] b2b34e9bdb5d899ee8a717fcc8499bb6e2e76a03 0 458 1067 1066 2013-05-12T02:54:35Z Jsfisher 1 1 revision wikitext text/x-wiki http://secure.netroedge.com/~phil/IRs/DSCN1472.jpg (high speed near-infrared photo from a digital camera (Nikon Coolpix 995) I modified just minutes before this photo was taken. I was staring in amazement at the LCD display while I snapped this picture. [http://holographyforum.org/phpBB2/viewtopic.php?t=2043 more on this]) I'm a scientist, engineer, and a wanna be entrepreneur. I was a Linux kernel developer for a while ([http://secure.netroedge.com/~lm78/ the project] still runs strong with the help of others), I have a degree in both computer science and computer engineering (the first is mostly software, the other hardware). I'm a weak lab sort. I'm impatient. For example, I hate movies, they take too long. So I spend a vast majority of my waking hours doing work on a computer (I prefer Linux for work, I support Macs at work, and have a few Windows machines for games and evil proprietary needs). I'm the IT, IS, DBA, telephone, sometimes backend web programmer, and general tech support guy at a small advertising/graphic design agency. As far as holography goes, I got amazed with holograms and lasers in middle and high school. At the time, though, it was expensive, very vague, and sometimes dangerous. Alas, I was completely unsuccessful at creating a hologram, and most likely I found out much later due to some useless Kodak film that was pushed on to me. My doubts lifted when I made a hologram in an unused bathroom at high school during electronics class (the closest thing to a hands-on science class at the time) using Agfa film (which at the time seemed to be getting very hard to get). Later, it was only after finding out about the Holography Forum that I got back into making, buying, and helping those making holograms (where I can) that I got back into the hobby. I'm proud to help Colin, Michael, John, and the many others who work hard to make holography less a monopoly, less scary, less mystical, and simply fun and creative. (PS- I have a problem with using too many parenthesis (as if you didn't notice!), but deal with it! This is my space! ;') [[http://www.holographyforum.org/HoloWiki/index.php?title=Talk:Phil_Edelbrock&action=edit Have a comment? Click here.]] b369b63998b6e7936230988f6be9e6eb7d09479b 0 459 1069 1068 2013-05-12T02:54:35Z Jsfisher 1 1 revision wikitext text/x-wiki This section could use some work on laser-lit transmission holograms and refinement on the instructions for rainbows. ==General tips== * Use a digital camera. This will allow you to experiment to your hearts content without worrying about burning film. * Always turn your flash off, it will never help when photographing holograms. * Use a good steady tripod. Minor shake can cause ugly blurring in what could otherwise be a good photo. * If your camera has them, experiment with the manual exposure, metering, aperture and ASA controls. If your camera records all these settings in the exif data you won't need to write down what settings go with what picture. If anything is missing, make sure you take good notes so that you'll know what settings give you the best results. * Take your pictures in a dark room (excepting the single light used to illuminate your hologram) so that you won't see reflections of the room in the surface of your hologram. * If you can't make your room sufficiently dark and find that reflections of you or your camera are visible in the hologram glass, do the following. Take a large sheet of black cloth and cut a slit in it big enough to pass the lens of your camera through. Place sheet over your camera with the lens sticking through the slit and wrap a rubber band around the slit edges and lens so that the sheet is held in place. When taking your pictures drape the sheet over your head so that you and the camera can't be seen in the hologram glass. You may need a sheet large enough to cover the legs of your tripod if it's highly reflective. * If your camera has difficulty focusing on the image in the hologram instead of the glass take the hologram and lean it such that it is shimmed away from a flat surface or wall by an inch or so. Take a piece of white card and lie/lean it next to the hologram at the flat surface or wall (it will be an inch or so further away from the camera then the hologram). Now take the digital camera and point it at the white card and hold the button half way down. This locks in the focus and exposure of the white card. Now without releasing the button, move to the hologram and push the button in the rest of the way which will take the photo. By adjusting the distance separation between the card and the hologram (1/4 inch, 1/2 inch, 1 inch etc.) you should be able to get the hologram to be in focus. By adjusting where you point the camera on the card (edge or middle) and by holding down the button you should be able to lock in different degrees of exposure/aperture as locking on to the hologram itself overexposes the photo. * For lighting use a single halogen bulb plugged into a dimmer so that you get a clear single source of light and can control the brightness to get the best image. * Optileds can also be used to provide narrow-band replay light that results in less haze and clearer, deeper hologram reconstruction. ==Rainbow Holograms== To photograph these, if you want the greatest detail, I would recommend the following: * Make sure you have a really good point source of light, so the image is as sharp as possible. As you have a camera and tripod, you can use a long exposure, and the image does not have to be bright. So move your reconstruction light as far away as convenient from the hologram. The image will get dimmer but sharper. I am assuming the hologram is designed to be viewed with a collimated or near-collimated beam. * Now move your camera towards or away from the hologram till the image is a single color. Now you are in the projected 'slit' of the rainbow hologram. * Move the camera up and down till the center of the image is the color you want the image to be. * Move camera towards or away till the entire image is in that color. * Switch off flash; put camera ASA setting to minimum, e.g. 50 * Focus the image. Simple digital cameras don't normally allow manual focusing these days, but try different things till the image looks as sharp as possible. * If you have any control, keep the aperture as wide as possible, i.e. f/2 is better than f/16. This will minimize speckle. * To minimize shake you could put on timer and the camera will shoot a few seconds after you press the button. All would be so much simpler with an old fashioned manual camera, or else a pro digital camera with full control. Good luck. ==Links== 2354bd98dd43215e9669cf8ce917d3b3d4daea73 0 460 1071 1070 2013-05-12T02:54:35Z Jsfisher 1 1 revision wikitext text/x-wiki ===Notes from Ed Wesly=== Here are some notes on photo-resist technology that go against the grain of conventional wisdom that you may have heard or read. The thickness of the resist is not critical. The original application of making masks for the micro-circuit industry dictated the micron or so thickness, as the resist would be developed all the way down to the substrate so it was laid bare for etching. A good friend of mine, Manfred Stelter, who runs Process Technologies Inc, is the father of the chrome on glass technique. The resist is exposed, then developed so that the metal is bare in some parts, and then immersed in an acid, so the bare spots are etched, while the areas covered by the coating are not. Hence the term photo-resist, as it resists the acid. That is why the developer is an alkali. I have seen Drano or NaOH used, but I would recommend getting the Shipley developer, as it has some sort of surfactants and who knows what else secret ingredients in it. There are many developers, we used 303A. Ferric Oxide, or rust is the usual way that the holographic plates are sold. It is put on top of the glass, then the resist on top of it. It could be etched to make a mask, but for our application it is a good anti-halation layer, as its orange color absorbs the blue photons. But we would spray the backs of the ordinary single strength window glass with Krylon Flat Black Acrylic, which could be soaked off with water if the paint didn’t get too dry. Shipley does not sell direct, and when I typed in Shipley.com, I got this site: http://electronicmaterials.rohmhaas.com/ which is hard to navigate. We used 1813, diluted with its thinner 1:1. If you are going to electroform the resist, you will also need the stripper to remove the resist from the first generation. You could use the developer, but it might damage the silver. Originally we got the plates from Towne as John mentions above. http://www.townetech.com/ Another source we used was: [url]http://www.teliccompany.com/ [/url] as they would coat bigger sizes. PR plates cost a lot, but they are in the same ballpark as AgX plates nowadays! We coated our own plates, 12” by 12” became our standard, but we went all the way up to 42” square to make huge gratings! So here is how we would do it, courtesy of Steve Provence, one of the wildest of the wild men in holography ever! He is out of the business, so I don’t think it is a problem. Good luck, Jamonero! (He went into the Prosciutto business!) The plate must be scrupulously cleaned with distilled H2O and a little Alconox. It must be rinsed with the clean water, no additives, and let to dry completely, absolutely no water. Because the next step is to treat the surface with HMDS, some sort of silane. I forget the brand and the US distributor of this Japanese product. The directions say fume the plate with it, but not having a big enough fume box, we just spun it on. It dries pretty quickly. But it does evolve ammonia in contact with water, so make sure everything is dry in the spin area. Then we would spin at record turntable speeds, like 80 rpm. This goes against the usual conventional wisdom, but be don’t need a super thin layer like the electronics industry for etching, since we are just picking up the surface relief. So don’t worry about the fast start and spin like you read. And in regards to a question above, the thickness does not affect the sensitivity. Most of the resist will fly off the plate as it starts spinning, but if you keep the bowl around the spinner clean, you can recycle it! We would pour on the resist, then turn on the spinner. After spinning, we would let the plate sit on the spinner to dry a few minutes before packaging. Then we would let them sit in their box in the dark in a clean area for a week before shooting. Although the instructions say to bake the plates, this is only to remove residual solvents. A slow cure does the same. You can use the plates sooner than that, but they will be faster. Boy, do you do need blue photons! We shot with Argon 458 nm for stereograms, as we used Agfa Millimask for the H1, which would be way too scattery at the Krypton 413, which was used for the big gratings. Provence used 413 nm for his objects and 2D/3D jazz, since he shot PR masters. At first we used the 442 nm of the He-Cd for the Dotz! Machine, but would only get about 3000 hours out of the tube before it ran out of Cadmium. This dot-matrix machine was used 24/7, so it was like two $5k tubes a year, so we switched to a 405 nm diode eventually. And the deeper the lambda, the more sensitivity. Exposure doses were about 1000X more than AgX. Yes, you read that right! Our benchmark was 93 milliJoules compared to the 200 microJoules of MilliMask, and we would bracket over and under that by 1/3 stops to really tune it in. At the beginning we used ratios of 40:1, but then tested and brought it down to 10 or 5 to 1. Developing times are ridiculously short: 6 to 8 seconds! We would plunge the plate into the developer, diluted 1 part D to 6 parts H2O, and agitate furiously! Then yank it out as quickly as possible, to be plunged into running 18 MegOhm water for a couple of minutes. A hair dryer took care of the water at the end. Some people like to develop under a yellow bulb, but we had automated equipment to handle the exposure angle, so we could gang up multiple exposures on one plate. Play with dilution and times to find the method that suits your style. If you do dabble in resist, you need to silver the plates to find the best result for embossing. This company sells spray and brush on chemicals, and will take credit cards over the phone as opposed to someplace else that want you to set up an account, etc. [url]http://www.peacocklabs.com/[/url] We would pick the best expo to the eye, then double it, as the embossing process can be quite lossy. Another thing that goes against conventional wisdom is that you can shoot Single Beam Reflections with photo-resist! I would never have thought of that, but one of my student workers did it for the heck of it on an unbacked plate, and it worked! The reason it worked is that the only time the reflection Bragg planes are parallel to the substrate is when both beams are hitting the plate along the normal. But with the usual object behind, reference from above geometry, the fringes are no longer parallel to the substrate but break the surface of the coating. Once silvered, it didn’t look too bad, except for the spurious twin image not unlike a Gabor hologram. So if anyone is serious about setting up a resist lab, I am available for consulting. PM me if interested. _________________ I want some blue photons! 1a4976dda00a42fda7d1705b1648848898537e28 0 462 1075 1074 2013-05-12T02:54:36Z Jsfisher 1 1 revision wikitext text/x-wiki I am putting in notes. If anyone wants to add to this feel free. Definition: [[Image:Reflection_Polarization.png]] Reflection of a plane wave from a surface perpendicular to the page. The p-components of the waves are in the page, while the s components are perpendicular to it. rpar=(tan^2(alpha-beta)/tan^2(alpha+beta) rperp=(sin^2(alpha-beta)/tan^2(alpha+beta) alpha=angle of incedence beta=transmitted angle ===S-Type=== [[Image:SPolarization.jpg]] S-Type ===P-Type=== [[Image:PPolarization.jpg]] P-Type Polarizaton P-Polarization is used when you need to minimize the reflection off an interface between two materials of differing index of refraction. The index of refraction of air is about 1 and most glasses are about 1.5. For these two the angle of least reflection is about 56 deg. and is known as the [[Brewster's Angle]]. ===Finding P-Type Polarization=== One way to determine p-polarization is to set up your plateholder at [[Brewster's Angle]] (about 56 deg) and place a single piece of glass in it. Hit the glass with your spread beam. The glass is going to reflect some of the light hitting it, so place a white card in this reflected light path (in order to view it). If you rotate your laser head, you will notice that this reflected light becomes brighter and dimmer. Find the spot within the rotation where the reflected light is at it's dimmest on your white card, and you've got it. There should be two spots for this with every 360-degree of rotation. With a HeNe, you'll always have a "little" bit of light reflected. With a properly-running diode, the reflection will go completely out on the card (100% -- or VERY close to 100% -- transmission through the glass). ===Finding S-Type Polarization=== The easiest way to find S-Type Polarization is to find P-Type first and mark the top of your laser. Rotate the laser 90 degrees and you are at S-Type. Another method is to make a set up like for finding P-Type Polarization and place a light meter in the reflected beam. Adjust the rotation of the laser until the reflected light is a maximum. ===Testing Materials for Bifingence=== Many plastics will act as a bad wave plate. They will take your linear polarized laser beam and make it elliptical. Fortunatly there is a easy way to check. Place the sample of the material in question in between two crossed polarizers. If you see colors then it is acting to rotate the polarization. [http://en.wikipedia.org/wiki/Polarization Wikipedia's Article on Polarization] 6b2781b5f97dd66f881108bb66e89901d362d9de 0 464 1079 1078 2013-05-12T02:54:36Z Jsfisher 1 1 revision wikitext text/x-wiki The history of photopolymers may actually go back as far as the early 19th century when French photo pioneer Nicephore Niepce (http://www.niepce.com/pages/inv1.html#) carried out experiments with light-sensitive bitumen of Judea. Previously applied by the printing industry, photopolymer materials have meanwhile become an essential part of our daily life (from adhesives to optical memories). In the late 1960s companies like Hughes, Bell, RCA, DuPont, Canon, Polaroid started introducing photosensitive polymers for holography. In the meantime a great many photopolymer systems have been developed. Generally these light-sensitive compositions were formed of a photopolymerizable monomer, an initiator system and a polymer binder. Photopolymerization may be defined as the reaction of monomers or macromers to produce polymeric structures upon light-induced initiation. In photopolymer systems designed for holography index modulation usually is caused by refractive index changes. Upon actinic radiation polymerization is being initiated within the recording layer creating thus areas of increased molecular weight, converting a monomer into a polymer. Colburn/Haines (Volume hologram formation in photopolymer materials, Applied Optics, Vol. 10, 1971, pp.1636-1637) point out: ''In general, hologram formation in photopolymers is a three-step process. First, a normal exposure is made to the interference pattern to be recorded; this initial exposure polymerizes part of the monomer, with the amount of polymerization being a function of the intensity of the illumination. Monomer concentration gradients, caused by variations in the amount of polymerization, then give rise to the diffusion of the relatively small monomer molecules from regions of higher concentration to regions of lower concentration. With the completion of the diffusion step, the photopolymer is exposed to light of uniform intensity until the remaining monomer is polymerized.'' In a holographic setup the variations of light intensity will translate into refractive index changes. So far most photopolymer materials represent almost ideal phase media. In order to achieve maximum index modulation each component needs to be adjusted to each other with regards to optimizing refractive index differences. Such criteria might equally apply to components like solvents, binders, plasticizers, surfactants etc. Photopolymers can be spectrally sensitized over a wide range of wavelengths from UV to IR. Carré/Lougnot (Photopolymers for holographic recording: from standard to self-processing materials, J. Phys.III France 3, 1993, p.1445, www.edpsciences.org/articles/jp3/ref/1993/07/jp3v3p1445/jp3v3p1445.html) distinguish four categories: "dry formulation containing a polymeric film-forming binder (substrate), a dissolved monomer and a photoinitiating system; liquid or highly viscous coating containing monomers with several reactive functions and an initiating system; dry film composition containing crosslinkable, dispersed or grafted structures or unreacted double bonds and an initiating system; polymer film composition containing sensitive groups capable of undergoing photomodification (isomerization) or photodegradation (cleavage)." In order to provide the photosensitive material with sufficient mechanical strength, many systems contain a binder material. However, the binder tends actually to lower the diffusion of the monomers within the recording layer, preventing thus full polymerization. Such systems may hence suffer from insufficient efficiency and reduced index modulation. One way to get around that issue is to subject the recording layer to a thermal treatment following the laser exposure and the subsequent UV post-exposure. The temperature rise will increase diffusion speed to enhance the degree of polymerization. Liquid post-treatment of the fully polymerized layers may be carried out to influence paramters like playback wavelength and bandwidth. While most systems used to rely on radical polymerization, there has been increasing interest in cationic photoinitiators. The latter are based on the generation of an acid, which forms upon actinic radiation and promotes cationic polymerization. Dupont makes a line of photopolymer films available for large applications. It is reported to nolonger be available for art holography markets. [http://www.dupont.com/holographics/ Dupont] Polaroid makes a line of photopolymers as well. DMP128. [http://www.dupont.com/holographics/technicalpapers.html Dupont's Technical Papers] 063799f88cc8795edd6feb0c7afc197c44b41d10 0 465 1081 1080 2013-05-12T02:54:36Z Jsfisher 1 1 revision wikitext text/x-wiki POPULAR OPTICS by Sam Brown, Edmund Scientific Company, Barrington, New Jersey, 1974. “This book is a reprint from several smaller booklets published by Edmund Scientific Co. during the past fifteen years. Most of the standard optics specified are currently available, but some military surplus items are long gone. Where practical a substitute lens has been mentioned - in all cases the current Edmund catalog is your guide.” From the contents page. It’s 30+ years later, but still some of the same optics are available. And there still is a need for a real how-to book on building simple optical devices like overhead projectors, opaque projectors, telescopes, collimators, magnifiers, etc. One of the great features of this book are its formulae. They take the Simple Lens Formula and break it into all its permutations. For instance, if you know the object distance and focal length for an imaging scenario, you can find the magnification by looking up the appropriate formula and plugging and chugging. They also give examples of practical calculations for all formulae, using whole numbers so that it is easy to see the math in action. I haven’t seen it in the Edmund catalog recently, but who knows if there isn’t a box of them in a store room in New Jersey. $12.95 last list price, but the same information is found in books costing far more! And not as interestingly illustrated! -Ed Wesly 021675a644fcfef49214a2cb1139a7863146ff72 0 466 1083 1082 2013-05-12T02:54:37Z Jsfisher 1 1 revision wikitext text/x-wiki Post-Swelling is used when the replay color of a reflection hologram is too blue. Post-swelling expands the fringe structure shifting the replay color more gold or red. Post swelling can be achieved with sorbitol. [[Blyth Colour Tuning]] [http://en.wikipedia.org/wiki/Sorbitol Wikipedia page on Sorbitol] 042182d608eba01cd7fe97cb9604cbb72a25ae16 0 467 1085 1084 2013-05-12T02:54:37Z Jsfisher 1 1 revision wikitext text/x-wiki Using power tools saftley is a very importent step that is often overlooked in the rush to get a project together. When in doubt read the manual! More information can be found on the pages for [[Shop Basics|specific tools]]. *Wear safety glasses! (Nothing is 3-D with only one eye!) *Wear hearing protection. *Don't wear gloves with drills or drill presses. *Don't cross cut with the fence on a table saw. *Use a vice in a drill press. *Check the underside of a cut before skill sawing. *Pay attention. *Don't ever put your body at risk. Stop. Make a jig. be736f85f56ad79b134b714ee80df4243e04cfc0 0 468 1087 1086 2013-05-12T02:54:37Z Jsfisher 1 1 revision wikitext text/x-wiki Pre-swelling is used to make the replay color of a reflection hologram shorter. It works by expanding the gelatin before exposure and allowing the gelatin to shrink after exposure therefore making the fringe spacing closer. [[TEA]] The most common method for pre-swelling. efa0b9c6f3f70374a4d404443fa54f8c4801b795 0 469 1089 1088 2013-05-12T02:54:37Z Jsfisher 1 1 revision wikitext text/x-wiki ===Cristiano Perrucci's Method=== #- hand wash for a few a minute with sponge and dish detergent #- soak in 50% domestic bleach for 6-8 hrs #- wash in hot tap water (~45C) scrubbing with a sponge for a minute #- final wash in R.O. water for a few seconds #- dry with a towel #- final cleaning with Glassex (Windex in the USA?) this procedure works fine for MBDCG If I'm recycling old homemade plates, I start cleaning procedure from step 3 until all old emulsion has been washed out. Cleaning plates is the most boring task of DIY holographic plates, I liked to minimize time spent for this crucial step. ===Hans' Method=== I have had great results with this method: Previously I had great trouble with sticking gelatin to glass by silane'ing the glass with a solution of silane+acetone. I have found a new formula (from Bjelkhagens book) that seems to work much better for me. A mix is made with 40% silane + 45% Isopropylalcohol + 5% water. After 24 hours, this mix is further diluted with Isopropylalcohol to 5%. Then rub the glass thouroughly with this liquid and let it rest for about two hours. I then cleaned the glass further with glassex before application of the gelatin. I always take 1cc of this solution and then add 19cc of IPA. The diluted solution can be used for about two days. Just rub it on a plate with a towel. You will see a white haze on the plate. I then put the plate away for a couple of hours and clean with a ammonia based glass cleaner. If you wait more than a day before cleaning the plate with glass cleaner, the white haze becomes very difficult to remove. I have been using kitchen gloves. I also use goggles and a painter's mask with carbon filters. The undiluted Silane is nasty stuff. You don't want to get that on your skin or breathe it. Mix it in a fume cuboard if you can. I mix it always outside the house. ===Adam's Methods=== I soak my plates overnight in 10% potassium hydroxide aqueous/isopropyl solution (1 part alcohol per 6 parts of water) . I rinse them in warm tap water (rubbing with latex gloves - one side of the glass will make a sound when hydrophilic), rinse in DI/distilled water and wipe with towel paper until dry, wipe with a clean cloth (of silk for example) and blow with canned air. 2 days ago after such treatment, courtain coating (10% culinary gelatin, at 80deg.C), hardening in alum/formaldehyde (2 batches) and curing at 60deg.C I left my plates in DI water for 24 hours (to remove traces of a hardener). Today the gelatine is still fine and can be removed only by scratching with a nail. I hope it helps. The other way to clean plates would be soaking them in car battery acid solution with 10% potassium dichromate added. It worked with lab glass, but I haven't tried it for holographic plates. This mixture is supposed to be cancerogenic, so maybe it would be better to use KOH solution if possible. ==JohnFP's Method== For my standard DCG I soak the plates in 5% HydroChloric Acid at least 12 hours. I then scub them with a plastic wooly used to clean no stick pans in the Acid. I then put them in running how water and scrub them again in the hot water with the plastic wooly. I then set them in a rack and before they dry completely I wipe them with a fresh clean paper towel. It is important that there is a very little moisture on the glass during this wiping. I then blow them off with air. efa0a05f4070b968b6b88ca09951533de1dbe44d 0 470 1091 1090 2013-05-12T02:54:38Z Jsfisher 1 1 revision wikitext text/x-wiki '''Gelatin''' *by Dr. Bernard Cole *Copyright - 2006 Bernard Cole - This is not Open Source Copyright *[http://www.gelatin.co.za/ Dr. Bernard Cole's Web Site] [[Image:BCole.jpg]] ===INTRODUCTION=== Gelatin is a substantially pure protein food ingredient, obtained by the thermal denaturation of collagen (1), which is the structural mainstay and most common protein in the animal kingdom. Today gelatin is usually available in granular powder form, although in Europe, sheet gelatin is still available. There are two main types of gelatin. Type A, with isoionic point of 7 to 9, is derived from collagen with exclusively acid pretreatment. Type B, with isoionic point of 4.8 to 5.2, is the result of an alkaline pretreatment of the collagen. However, gelatin is sold with a wide range of special properties, like gel strength, to suit particular applications. Gelatin (2) forms thermally reversible gels with water, and the gel melting temperature (<35°C) is below body temperature, which gives gelatin products unique organoleptic properties and flavour release. The disadvantage of gelatin is that it is derived from animal hide and bone (not from trotters as is a common perception), hence there are problems with regard to kosher and Halal status and vegetarians also have objections to its use. Competitive gelling agents like starch, alginate, pectin, agar, carrageenan etc. are all carbohydrates from vegetable sources, but their gels lack the melt in the mouth, elastic properties of gelatin gels. ===CHEMISTRY and BIOCHEMISTRY=== Gelatin is an amphoteric protein with isoionic point between 5 and 9 depending on raw material and method of manufacture. Like its parent protein, collagen (3), it is unique in that it contains 14% hydroxyproline, 16 % proline and 26 % glycine. The only other animal product containing hydroxyproline is elastin and then at a very much lower concentration, so hydroxyproline is used to determine the collagen or gelatin content of foods. In brief, the protein is made up of peptide triplets, glycine - X - Y, where X and Y can be any one of the amino acids but proline has a preference for the X position and hydroxyproline the Y position (3). Approximately 1050 amino acids produce an alpha-chain with the left-handed proline helix conformation. Collagen exists in many different forms but gelatin is only derived from sources rich in Type I collagen which contains no cystine, however, hide or skin contains some Type III collagen which can be the source of traces of the traces of cystine found in some gelatins. Although Type I collagen contains no cystine, the alpha procollagen chains excreted by the cell do contain cystine at the C terminal end of the protein which is thought to be the site of assembly of 3 alpha-chains. The three chains then spontaneously (4) coil together, zipper fashion, to form a right-handed helix. After spontaneous helix formation, cross links between chains are formed in the region of the N terminal telopeptides (globular tail portion of the chains) and then the telopeptides (containing the cystine and tyrosine of pro-collagen) are shed leaving the rod-like ca. 3150 amino acid containing triple helix . These collagen rods assemble together with a quarter-stagger to form the collagen fibre and the fibres are stabilised by further cross-links. Gelatin is the product of denaturation or disintegration of collagen. Initially the alpha-chains of collagen are held together with several different but easily reducible cross-links. As the collagen matures, so the cross-links become stabilised (3). Then as time progresses the eta-amino groups of lysine become linked to arginine by glucose molecules (Maillard reaction) to form the pentosidine type cross-links which are extremely stable (5). Hence when the alkaline processing is used on young animal skin the alkali breaks one of the initial (pyridinoline) cross-links and as a result, on heating, the collagen releases, mainly, denatured alpha-chains into solution (5). Once the pentosidine cross-links of the mature animal have formed in the collagen, the main process of denaturation has to be thermal hydrolysis of peptide bonds resulting in protein fragments of various molecular weights i.e. polydisperse protein fragments. With the "acid process", the collagen denaturation is limited to the thermal hydrolysis of peptide bonds with a small amount of alpha-chain material from acid soluble collagen in evidence (6). Nutritionally, gelatin is not a complete protein food because the essential amino acid tryptophan is missing and methionine is only present at a low level. Type A gelatin (dry and ash free) contains 18.5 % nitrogen, but due to the loss of amide groups, Type B gelatin contains only about 18 % nitrogen (7). Gelatin is abnormally stable and a special catalyst has to be used to obtain the correct Kjeldahl nitrogen content. The amino acid analysis of gelatin (8) is variable, particularly for the minor constituents, depending on raw material and process used, but proximate values by weight are: glycine 21 %, proline 12 %, hydroxyproline 12 %, glutamic acid 10 %, alanine 9 %, arginine 8%, aspartic acid 6 %, lysine 4 %, serine 4 %, leucine 3 %, valine 2 %, phenylalanine 2 %, threonine 2 %, isoleucine 1 %,hydroxylysine 1 %, methionine and histidine <1% with tyrosine < 0.5 %. It should be remembered that the peptide bond has considerable aromatic character, hence gelatin shows an absorption maximum at ca. 230 nm. Collagen is resistant to most proteases and requires special collagenases for its enzymic hydrolysis. Gelatin, however, is susceptible to most proteases, but they do not break gelatin down into peptides containing much less than 20 amino acids. The cross-linking of gelatin with aldehydes is being used to extend the uses of gelatin. In particular, treatment of gelatin films with glutaraldehyde is receiving considerable study in order to improve their thermal resistance, decrease their solubility in water as well as to improve their mechanical properties. In Japan and Brazil the cross-linking of gelatin using the enzyme trans-glutaminase and its use in joining gelatin to other proteins, is approved for food use. An occasional phenomenon is the loss of gelatin solubility after storage in a new kitchen cupboard where the residual formaldehyde vapour from the adhesives used, causes cross-linking of the gelatin. This reaction has been used to make gelatin adhesives water-resistant. Furthermore, the "smokes" used in food preservation are rich in aldehydes and thus can have unwanted reactions with gelatin. ===GELATIN MANUFACTURE=== There are a large number of unit processes used in the manufacture of gelatin and the raw materials from which it is derived are demineralised bone (called ossein), pigskin, cow hide, fish skin and in China, donkey hide is also used quite extensively. In theory there is no reason for excluding any collagen source from the manufacture of gelatin, but the ones above are the currently commercially available raw materials. Interestingly, in countries where pork is sold with its skin intact, there is no pigskin available for gelatin manufacture. There are basically two processes by which collagen is processed to gelatin: The acid process (studied in detail by Reich (9)) is mainly used with pigskin and fish skin and sometimes bone raw materials. It is basically one in which the collagen is acidified to about pH 4 and then heated stepwise from 50°C to boiling to denature and solubilize the collagen. Thereafter the denatured collagen or gelatin solution has to be defatted, filtered to high clarity, concentrated by vacuum evaporation or membrane ultra-filtration treatment, to a reasonably high concentration for gelation and then drying by passing dry air over the gel. The final process is one of grinding and blending to customer requirements and packaging. The resulting gelatin has an isoionic point of 7 to 9 based on the severity and duration of the acid processing of the collagen which causes limited hydrolysis of the asparagine and glutamine amino acid side chains. The alkali process (studied in detail by Cole and Roberts (10)) is used on bovine hide and collagen sources where the animals are relatively old at slaughter. The process is one in which collagen is submitted to a caustic soda or lengthy liming process prior to extraction. The alkali hydrolyses the asparagine and glutamine side chains to glutamic and aspartic acid relatively quickly (11), with the result that the gelatin has a traditional isoionic point of 4.8 to 5.2, however, with shortened (7 days or less) alkali treatment, isoionic points as high as 6 are produced. After the alkali processing, the collagen is washed free of alkali and treated with acid to the desired extraction pH (which has a marked effect on the gel strength to viscosity ratio of the final product). The collagen is then denatured and converted to gelatin by heating, as with the acid process. Because of the alkali treatment, it is often necessary to demineralise the gelatin solution to remove excessive amounts of salts using ion-exchange or ultrafiltration. Thereafter the process is the same as for the acid process - vacuum evaporation, filtration, gelation, drying, grinding and blending. Although gelatin is often considered a commodity like sugar, the descriptions of the processes and raw materials above, should indicates that gelatin has the potential for being a variable product and it behoves users to ensure that they are using the best product for each particular application. In the past, little emphasis has been placed on the animal age of the raw material, particularly in the case of gelatins from bovines, however it is now known that this factor plays a significant role in the molecular structure of the derived gelatin. The role of liming in the alkali process used to be considered one of progressive alkali hydrolysis of the collagen, which made it possible to denature the collagen at lower temperatures and thus maximise the yield of top quality gelatin. Recently, however, it has been shown that the role of liming is limited to the hydrolysis of one collagen cross-link which fluoresces at 290/380 nm and that liming has less and less effect on "extractability" as the animal gets older. The result is that alkali treatment times have been greatly reduced. One of the less well recognised effects of alkali treatment is the "opening up" of the hide collagen, as it is termed in leather manufacture, or the destruction of the proteoglycans associated with the collagen fibrils and this probably results in a more pure gelatin via the alkali process as is indicated by electrophoresis of the gelatin proteins (12). At present, enormous developments are being made in the understanding of the structure of collagen and the changes occurring with senescence, and these developments are bound to have an impact on the appreciation of the variables in gelatin, particularly at the molecular level. ===GELATIN SAFETY=== Gelatin is regarded as a food ingredient rather than an additive and it is Generally Regarded as Safe (GRAS). In 1993 the FDA reiterated the GRAS status of gelatin and stated that there was no objection to the use of gelatin from any source and any country provided that the hide from animals showing signs of neurological disease were excluded and also Specified Raw Materials were excluded from the manufacturing process. Although, at the beginning of the Bovine Spongiform Encephalopathy (BSE) scare in Europe the popular media brought suspicion on all products of bovine origin as being possible transmitters of the disease to humans as CJD, this was a thoroughly unscientific assessment of the dangers of spreading infection. It is now recognised that BSE is a neurological and brain problem and not associated with the hide of the animal. It is also recognised that the processes of manufacturing gelatin make it virtually impossible for the survival of a defective prion, if it were present in the first place. Detailed and unbiased information on BSE is available from the Institute of Food Science and Technology Web site. Hence, today, gelatin retains its GRAS status. Furthermore, the Joint Expert Commission on Food Additives (JECFA) placed no limit on the use of gelatin in 1970. Gelatin is an excellent growth medium for most bacteria, hence considerable care needs to be taken, during manufacture, to avoid contamination. This care is evidenced by the use of documented HACCP programs by manufacturers. In the same way to ensure product reproducibility, most companies are implementing ISO 9000 quality management systems. ===GELATIN PROPERTIES AND USES=== ====Solubility in water==== Gelatin is only partially soluble in cold water, however dry gelatin swells or hydrates when stirred into water. Such mixtures should generally not exceed 34 % gelatin. On warming to about 40°C gelatin that has been allowed to hydrate for about 30 minutes melts to give a uniform solution. Alternatively, dry gelatin can be dissolved by stirring into hot water, but stirring must be continued until solution is complete. This method is normally only used for dilute solutions of gelatin. If gelatin solutions are spray dried or drum dried from the sol state, the resulting gelatin is "cold water soluble" and such gelatins gel quickly when stirred into cold water. These gels are generally not clear, so the use of this form of gelatin is limited to milk puddings and other products where solution clarity is not required. The compatibility of gelatin in aqueous solution with polyhydric alcohols like glycerol, propylene glycol, sorbitol etc. is virtually unlimited and they are used to modify the hardness of gelatin films. In products with limited moisture availability, as in confectionery, and where there is another polymer, as in glucose syrup, competing for the available water, then gelatin can be precipitated resulting in loss of gelation and cloudiness. In these cases the gelatin solubility is very dependent on the charge on the protein molecule or the pH of the product. Hence, the further the product pH is from the isoionic pH the better will be the solubility and performance of the gelatin. ====Adhesive properties==== Possibly the oldest use of gelatin was as animal glue. For adhesion to take place a warm gelatin solution must be used and the gelatin must not have gelled before the surfaces to be glued are brought together. An example of this use of gelatin is in pharmaceutical or confectionery tableting and in liquorice all-sorts where it can be used to join the layers. ====Gelling properties==== The most common use of gelatin is for its thermally reversible gelling properties with water, for example, the production of table jellies. Gelatin is also used in aspic to add flavour to meat products while on gelling it also provides a pleasing shiny appearance to the product. In some cases gelling is known as its "water absorbing property": For example, in canned hams, gelatin can be added to the can before cooking. On cooking the exudate from the meat is absorbed by the gelatin and appears as a gel when the can is opened. In confectionery, gelatin is used as the gelling binder in gummy products, wine gums etc. In the manufacture of these products gelatin is combined with sugar and glucose syrups. Incompatibility between gelatin and glucose syrup can occur (13) and is a function of the concentration of glucose polymers containing more than 2 glucose units, contained in the syrup. Competition between gelatin and glucose polymers for water in low water content products can result in, at worst, precipitation of the gelatin and at best a marked loss in gelling properties or hardness of the product. It is also known that different gelatins with similar properties in water, can have very different properties in confectionery formulations. Some raw fruits like pineapple and papaya contain proteolytic enzymes like bromelin which hydrolyse gelatin and destroy its gelling ability. In such cases it is essential that the fruit is cooked to destroy the protease before the fruit is added to gelatin solutions. In general one can say that the lower the mean molecular weight (MW) of a gelatin the lower the gel strength and viscosity of its solution, however it has been shown that the collagen alpha-chain (MW 100 kD and gel strength = 364 g Bloom) is the main contributor of gel strength (14) and that higher molecular weight components (beta-chain with MW 200 kD, gama-chain with MW 300 kD and "microgel" with MW > 300 kD) make a relatively low contribution to gel strength but a high contribution to viscosity. ====Foaming properties==== Gelatin is a very efficient foam stabiliser and this property is exploited in the manufacture of marshmallows. Different gelatins have different foam stabilising properties and gelatin for this use needs to be carefully selected. However, the foaming properties can be standardised by the use of sodium lauryl sulphate (15), if this is permitted by local food additive regulations. In marshmallows the gelatin's film forming properties are also used to stabilise the foam on cooling, and because the product is normally not acidified, it has to have a much lower moisture content (>85 % solids) than gummy products (76 % solids) to avoid mould growth in storage. ====Protective Colloid/Crystal habit modifying properties==== If a gelled jelly is frozen, the product will suffer from syneresis and on thawing the clear jelly will disintegrate with much exuded water. However, if water containing 0.5 % gelatin is frozen, the water will freeze as millions of small discrete crystals, instead of forming a single solid block of ice. This effect is most desirable in "ice lollies" and is also used in ice cream manufacture to obtain a smooth product with small ice crystals and also to ensure that any lactose precipitates as fine crystals avoiding the development of graininess with time. ====Film Forming properties==== Gelatin's film forming properties are used in the manufacture of both hard and soft (pharmaceutical) capsules. Gelatin films shrink with great force on drying, hence such uses usually involve the addition of polyhydric alcohols to modify the adhesion and flexibility of the dry film. Also, for film forming, a gelatin with a high viscosity is preferred to one with a low viscosity, hence for hard capsules and in photography, ossein gelatin is preferred and commands a premium price. ====Emulsifying properties==== The amphoteric character as well as hydrophobic areas on the peptide chain gives gelatin limited emulsifying and emulsion stabilising properties used in the manufacture of toffees and water in oil emulsions like low fat margarine. ====Stability==== Dry gelatin has an almost infinite shelf life as long as the moisture content is such as to ensure that the product is stored below the glass transition temperature. The stability of gelatin in solution depends on temperature and pH. Generally, to minimise loss of gel strength and viscosity with time, the pH of the solution should be in the range 5 to 7 and the temperature should be kept as low as possible, consistent with the avoidance of gelation and the suitability of the solution viscosity to the particular application. Often the cause of degradation or hydrolysis of gelatin in solution is microbial proliferation, so gelatin solutions should not be stored for longer than is absolutely necessary, and after addition of the acid to confectionery formulations, the solution should be used and cooled/gelled with minimal delays. ====Microencapsulation - Mixed film forming properties==== Besides being precipitated by polymers competing for water, gelatin is amphoteric, i.e. it has both positive and negative charges on the molecule (and no net charge at the isoionic point). Hence, at a pH where the basic side chains do not carry a charge, acid groups for example from gum arabic can react with the basic groups of gelatin to form an insoluble gelatin-arabate complex which can be precipitated around emulsified oil droplets, forming micro-ecapsulated oil. The microcapsules are hardened with formaldehyde or glutaraldehyde before harvesting and drying. In this application the pI of the gelatin is critical. This process has been used in the food industry for encapsulating flavours. ====Milk - Food stabilising properties==== Gelatin is used as a stabilizer particularly in yoghurt, where the addition of 0.3 - 0.5 % acts to prevent syneresis thus allowing the production of stirred and fruit containing products. In this instance the gelatin reacts with the casein in the milk to reduce its tendency to separate water from the curd. Gelatin can also be used in cheese manufacture to improve yield and in the stabilisation of thickened cream. ====Fruit Juice Clarifying properties==== In "fining" applications, gelatin reacts with polyphenols (tannins) and proteins in fruit juices forming a precipitate which settles leaving a supernatant which is stable to further cloud formation with storage time. In wine, usage levels are about 1 to 3 g/hL and excess usage, which would lead to protein instability, needs to be avoided. Traditionally, low Bloom strength gelatins are used but it has been shown that high Bloom strengths are equally effective (16). However, from the practical point of view, the use of low Bloom Strength gelatin is cheaper and makes it easier to mix the gelatin into the bulk of the cold juice before gelation can occur. In this regard, it has become common practice to treat cold grapes, during the initial crushing process, with gelatin that has been hydrolysed to the extent that it can no longer gel. ====Texturising properties==== Gelatin is used in dried soups to provide the appropriate mouth feel (viscosity) to the final product. ====Nutritional properties==== As stated earlier, gelatin is not a complete protein source because it is deficient in tryptophan and low in methionine content, however the digestibility is excellent and it is often used in feeding invalids and the high level of lysine (4 %) is noteworthy. More controversially, studies have shown that the consumption of 7 to 10 g/day can significantly improve nail growth rate and strength (17) and it also promotes hair growth (18). Gelatin has also been shown to benefit arthritis sufferers in a large proportion of cases (19). ====Corrosive properties==== Although 304 stainless steel (s/s) can be used with milk, gelatin attacks 304 s/s and tubing can be perforated after a few months of continuous usage. With gelatin, it is essential to use 316 s/s and if heat exchanger plates are involved, the use of 316 s/s with the minimum specified molybdenum content of only 2 % can be unacceptable. ====Fish skin gelatin==== Fish skin gelatin is available commercially and can be produced for kosher use provided that the appropriate conditions are met (such as the use of fish having scales). Fish gelatin with normal gel strength has a normal hydroxyproline content (21) and is made from fish from warmer waters and not necessarily from fresh water, although this is normally the case. Fish gelatin with low or no gel strength (20), has a low hydroxyproline content (7) and is produced from cold water species which are sourced typically from the sea. The low gel-strength gelatin has been used to emulsify vitamin A before spray drying to give another type of microencapsulated product using gelatin. ===GELATIN TESTING METHODS=== The best published sources of gelatin testing methods are British Standard 757 of 1975 (22) or Standard Methods for sampling and testing gelatin, published by the GMIA (23) or the Pharmacopoeias. Many of the methods used in laboratories need to be modified to suit the peculiarities of gelatin. ====Identification==== Gelatin gives the normal positive trichloroacetic acid, biuret, ninhydrin tests for protein. The precipitate with 5 % tannic acid is a particularly sensitive test for very dilute solutions of gelatin. In addition the thermally reversible gelation of a 6 % solution in water between 10 and 60°C is unique for this protein. ====Gel Strength==== The most important attribute of gelatin is its gel strength and when determined by the standard method (22), is called the Bloom Strength. This is the force in grams required to press a 12.5 mm diameter plunger 4 mm into 112 g of a standard 62/3% w/v gelatin gel at 10°C. Several penetrometer type instruments have been adapted to determine Bloom Strength. A frequent question is how to substitute gelatin of one Bloom Strength for a gelatin of another. As a guide one can say: C x B½ = k (24) or C1(B1)½÷(B2)½ = C2 Where C = concentration, B = Bloom strength and k = constant, however, there are other considerations besides gel strength which can invalidate such a substitution calculation. For example, in a gummy formulation, the texture using 250 Bloom gelatin is far shorter than when 180 Bloom gelatin is used. ====Viscosity==== From the point of view of functionality, the solution viscosity of gelatin is probably the second most important parameter. The standard method calls for the viscosity of a 62/3 % solution at 60°C. Low viscosity (and a high gel strength) is required for poured confectionery, and high viscosity for film forming applications. In viscosity calculations, usually C logV = k but the model is not as good as is the mathematical model for Bloom calculations. ====Colour and Clarity==== Solution colour and turbidity or clarity are attributes which may or may not be important depending on the application. Poor clarity markedly affects the ability to measure colour (25) and at this stage there are no internationally accepted methods for determining these attributes, however, if clarity is good, then gelatin colour obeys Beer's Law. ====pH==== Solution pH (1%) is usually about pH 5 but can vary considerably. At this pH the viscosity of Type B gelatin is minimal and the gel strength is maximal, hence from the manufacturers point of view it is advantageous to manufacture gelatin at this pH. However, due to the strong buffering capacity of gelatin this pH may not be the most advantageous for the customer. ====Moisture==== The moisture content of gelatin may be as high as 16 %, however, more normally it is about 10 % to 13 % because at 13.0 % moisture content the glass transition temperature (26) of gelatin is about 64°C which allows particle size reduction to be a simple operation. In addition, at 13 % moisture content and 25°C gelatin is close to equilibrium with ambient air moisture contents of ca. 46 % RH. At 6 % to 8 % moisture content gelatin is very hygroscopic and it becomes difficult to determine the physical attributes with accuracy. Due to the variable granule size of gelatin, the rate of moisture loss at 105°C can be variable. Hence it is normal to add water to the gelatin powder before placing the sample in the drying oven. This means that the gelatin melts and water is lost from a uniform thin film of protein. It should be noted that metal dishes have to be used because, on drying, the film of gelatin shrinks and breaks containers of glass or ceramic. Finally, the drying of gelatin to very low moisture contents results in cross-linking and loss of solubility. It is thus difficult to distinguish between free and bound water in gelatin. ====Ash==== The gelatin ash content is determined by pyrolysis at 550°C. Usually ash contents up to 2.5 % can be accepted in food applications. However the nature of the ash can be important. For example, 2 % CaSO4 in gelatin can have excellent clarity in spite of the solubility product of the ash being exceeded (due to the crystal-habit modifying effect of gelatin), however on dilution of the gelatin in a confectionery formulation, the ash can precipitate. Furthermore, ammonia is often used as a pH modifier in gelatin preparation and salts like NH4Cl are not determinable by pyrolysis. ====Sulphur dioxide content==== Sulphur dioxide is used as a biocide and bleach in gelatin manufacture. The nationally permitted level of residual SO2 in gelatin is variable and the methods for its determination can give a great variation in results. It is known that gelatin promotes oscillating redox reactions (28,29) and the control of this contaminant is not easy. Hydrogen peroxide is often used to control the SO2 content of gelatin and sometimes the permitted level of this contaminant is also specified. It is interesting to note that both H2O2 and SO2 can be shown to coexist in gelatin. ====Heavy Metal content==== Once again the determination of heavy metals in gelatin can be a problem because of the difficulty of completely degrading gelatin and also because the main component of the ash in gelatin can be of low solubility, like calcium sulphate, hence with a variable ability to absorb traces of heavy metals. It must be recommended that internal standards be used wherever possible. ====Isoionic point==== The isoionic point of gelatin (27) is best determined by passing a 1 % solution of the gelatin at 40°C through a mixed bed column of ionexchange resin (Rohm & Haas MB3) at a flow rate of not more than 10 bed volumes per hour and measuring the pH of the eluate. It should be noted that on cooling, isoionic gelatin has poor clarity and the conductivity should be between 1 and 5 s/cm for Type B gelatin. ====Microbiological properties==== Gelatin is an excellent nutrient for most bacteria, hence the manufacturing processes have to carefully avoid contamination. Most countries have microbiological specifications for gelatin, but generally they are not very onerous. Total mesophyllic plate counts of 1000 are generally accepted with various countries limiting the presence of Coliforms, E. Coli, Salmonella, Clostridial spores, Staphylococci, and sometimes even Pseudomonades. ===BIBLIOGRAPHY=== ====General References==== A.J. Bailey and N.D. Light. Connective tissue in meat and meat products. Elsivier Applied Science. London and New York. (1989). M. Glicksman. Gum Technology in the Food Industry. Academic Press New York and London. (1969). G. Stainsby. Recent Advances in Gelatin and Glue Research. Pergamon Press, London New York, Paris, Los Angeles. (1958). A. Veis. The Macromolecular Chemistry of Gelatin. Academic Press - New York and London. (1964). A.G. Ward and A Courts. The Science and Technology of Gelatin. Academic Press. London . New York . San Francisco. (1977). ====Citations==== 1. A.J. Bailey and R.G. Paul. Journal of the Society of Leather Technologists and Chemists. 82(3), 104-110. (1998). 2. M. Glicksman. Gum Technology in the Food Industry. Academic Press New York and London. pp. 359-397. (1969). 3. A.J. Baily and N.D. Light. Genes, Biosynthesis and Degradation of Collagen in Connective tissue in meat and meat products. Elsevier Applied Science. London and New York. (1989). 4. D.J. Prockop. Matrix Biol. 16(9), 519-528. (1998). 5. C.G.B. Cole and J.J. Roberts. Proceedings of the International Union of Leather Technologists and Chemists Societies Congress. London. 57-64. (1997) 6. C.G.B. Cole and J.J. Roberts. Journal of the Society of Leather Technologists and Chemists. 80, 136-141. (1996). 7. J.E. Eastoe and A.A. Leach. A survey of recent work on the amino acid composition of vertebrate collagen and gelatin in Recent Advances in Gelatin and Glue Research. Ed. G. Stainsby. Pergamon Press, London . New York . Paris . Los Angeles. 1958. 8. P.V. Stevens. Food Australia. 44(7), 320-324. (1992) 9. G. Reich, S. Walther, F. Stather. Deutsche Lederinstitut, Frieberg/SA. 18, 15-23. (1962). 10. C.G.B. Cole. The Occurrence of Dark Coloured Gelatin. in Occurrence, Measurement and Origins of Gelatine Colour as Determined by Fluorescence and Electrophoresis. 19-155. Thesis. University of Pretoria. Pretoria. 0002. South Africa. 11. A. Veis. The Macromolecular Chemistry of Gelatin. Academic Press - New York and London. 196. 1964. 12. C.G.B. Cole and J.J. Roberts. Journal of the Society of Leather Technologists and Chemists. 80, 136-141. (1996). 13. W.M. Marrs. Gelatin/carbohydrate interactions and their effect on the structure and texture of confectionery gels in Progress in Food science and Nutrition 6, 259-268. Ed. G.O. Phillips, P.A. Williams, D.J. Wedlok. Pergamon Press. Oxford . New York . Toronto . Sydney . Paris . Frankfurt. 1982. 14. E. Heidemann, B. Peng, H.G. Neiss, and R. Moldehn. Proceedings of the 5th IAG Conference: Photographic Gelatin. Ed. H. Ammann-Brass and J. Pouradier. International Arbeitsgem. Photogelatine, Fribourg, Switzerland. 15. Federal Register. May 15, 1964. p. 6383. 16. W. Bestbier. Wynboer. 621, 6-62. (1983). 17. M. Schwimmer and M.G. Mulinos. Antibiotic Medicine and Clinical Therapy. IV(7), 403-407. (1957). 18. United States Patent 4,749,684. (Jun.7, 1988). B. Silvestrini ( to Bruno Silvestrini). 19. M. Adam. Therapiewoche 38, 2456-2461. (1991). 20. A.G. Ward. Conversion of collagen to gelatin, and chemical composition in Recent Advances in Gelatin and Glue Research. Ed. G. Stainsby. Pergamon Press, London . New York . Paris . Los Angeles. 1958. 21. European Patent 0 436 266 A1. (Published 10.07.91). S. Grossman. (to Bar Ilan University 22. Methods for sampling and testing gelatine. BS 757 : 1975. Gr8. British Standards Institution. 2 Park St. London W1A 2BS 23. Gelatin Manufacturers of America, Inc. Standard Methods for Sampling and Testing of Gelatin. GMIA, Inc., New York, 1986. 24. A. Veis. The Macromolecular Chemistry of Gelatin. Academic Press - New York and London. 392-396. 1964. 25. C.G.B. Cole and J.J. Roberts. "Gelatine Colour Measurement". Meat Science. 45(1), 23-31. (1997) 26. M.H. McCormick-Goodhart. Research Techniques in Photographic Conservation. Proceedings of the Copenhagen Conference. 65-70. (May 1995). 27. A. Veis. The Macromolecular Chemistry of Gelatin. Academic Press - New York and London. 107-113. 1964. 28. C.R. Chinake and R.H. Simoyi. S.Afr.J.Chem., 48, 1-7. (1995). 29. Z. Melichova, A. Olexova and L. Treindel. Chemical Abstracts. Number 123:267635. Z. Phys. Chem. (Munich). 191(2), 259-64. (1995). 251c1fa0adb5569e49c8f02f70be756389cba40d 0 471 1093 1092 2013-05-12T02:54:38Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Quantum''' - smallest indivisible unit of radiant energy. '''Quarter Wave Plate''' - a optical element used to convert polarization in between circular and linear. '''Quarterplate''' - negative or print format measuring 3 * x 4 * inches. It's one quarter the size of a full plate (8 * x 6 * inches). '''Quartz-iodine lamp''' - compact tungsten filament lamp designed to maintain its color temperature and light intensity throughout its working life. 5394f9cbfbea88600a65b95086787f3632311972 0 472 1095 1094 2013-05-12T02:54:39Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Rack and pinion focusing''' - mechanical focusing system used on copying or monorail cameras. A pinion engages a rack on a slide. Focusing is achieved by turning a knob or wheel, which moves the lens or image panel. *'''Radiography''' - technique of using X-rays, gamma rays and charged particles to form shadow images on photographic materials. Used in medical and industrial research because of its ability to penetrate opaque objects. *'''Rayographs''' - term coined by Man Ray and his friends for pictures made by placing directly on photographic paper (i.e. photograms). *'''Rear focus''' - refers to the focused area behind the picture's subject. *'''Rebate''' - margin on photographic film surrounding the image area. *'''Reciprocity failure''' - in photographic emulsions occurs when exposure times fall outside a films normal range. At these times an increase in exposure is required in addition to the assessed amount. This can be achieved either by increasing intensity or time. *'''Reciprocity law''' - states that exposure = intensity x time, where intensity is equal to the amount of light and time is equal to the time that amount of light is allowed to act upon the photographic emulsion. *'''Reconstituted image''' - photograph produced by translating light from the subject into electronic signals. *'''Red eye''' - effect encountered when light from a flash unit travels parallel to the lens axis during exposure. *'''Reflected light''' - light bounced off a subject, not falling on it. *'''Reflected light reading''' - measurement by a light meter of the amount of reflected light being bounced of the subject. The light meter is pointed towards the subject. *'''Reflections''' - rays of light which strike a surface and bounce back again. Specular reflection occurs on even, polished surfaces; diffuse reflection occurs on uneven surfaces, when light scatters. *'''Reflector''' - any substance from which light can be reflected. It also describes a white or gray card used to reflect from a main light source into shadow areas. *'''Refraction''' - change in direction of light rays as they pass obliquely from one transparent medium to another of different density, e.g. air to glass. *'''Refractive index''' - numerical value indicating the light bending power of a medium such as glass. The greater the bending power, the greater the refractive index. *'''Register''' - exact alignment when overlaying separate images. *'''Register punch''' - punched used to make alignment holes in film or paper for registering images. *'''Rehalogenization''' - process by which black metallic silver is converted back to silver halides. It is used in bleaching for toners and intensification. *'''Relative aperture''' - measurable diameter of the diaphragm divided by the focal length of the lens in use and expressed in terms of "f" numbers, marked on the lens barrel. *'''Replenishment''' - addition of chemicals to a processing solution to maintain its characteristics, e.g. developers are replenished with reducing agents as the old ones are exhausted through use. *'''Resin coated paper''' (RC) - printing paper with a water repellent base. RC Paper can be processed faster, require less washing, and dry more quickly than fiber based papers. *'''Resist''' - protective but removable layer applied to a surface in the form of a pattern or image. Used to prevent chemicals solutions reaching covered areas. *'''Resolving power''' - ability of the eye, lens or photographic emulsion to determine fine detail. In photography, the quality of the final image is a result of the resolving power of both the lens and the sensitive emulsion. Resolution is expressed in terms of lines per millimeter which are distinctly recorded or visually separable in the final image. *'''Restrainer''' - chemical constituent of developing solutions which helps prevent reducing agents from affecting unexposed halides and converting them to black metallic silver. *'''Reticulation''' - regular crazed pattern created on the emulsion surface of negatives which is caused by extreme changes of temperature or acidity/alkalinity during processing. *'''Retouching''' - after treatment carried out on a negative or print, in the form of local chemical reduction, local dye or pencil additions or air-brushing. The purpose is to remove blemishes on the negative or print. *''Reversal materials'' - materials specifically designed to be processed to a positive after one camera exposure. *'''Rising front''' - camera movement enabling the front lens panel to be raised or lowered from its central position on most view cameras. *'''Rods''' - receptors forming part of the retina at the back of the eye sensitive only to variations in brightness, not color. See Cones. ae2215a0d0b8fbb855afdf6b14544933ba44d34d 0 473 1097 1096 2013-05-12T02:54:39Z Jsfisher 1 1 revision wikitext text/x-wiki '''Rasps''' [[Image:RaspTeeth.jpg]] A rasp looks like a file but instead of having long teeth the theeth are brought to points. The come in a varity of shapes and tooth patterns. For the smoothest finish use rasps that have been cut by hand to a random tooth pattern. They come in a varity of shapes and teeth patterns. A inexpensive general porpous rasp is called a 4 in 1 rasp and has four tooth patterns on one rasp. '''Rifflers''' [[Image:Riffler.jpg]] Rifflers are related to rasps however a riffler has the cutting surface bent to lift the handle out of the work area. Rifflers are used for cutting shallow depressions. Rasps and rifflers should only be used on soft materials like wood, soapstone etc. Metal will dull them quickly. They can be sharpened many times in an acid bath. 043599f63d77bbb44c8a9b73a7685a07c558faf6 0 474 1099 1098 2013-05-12T02:54:39Z Jsfisher 1 1 revision wikitext text/x-wiki This page is under construction! Here is an example MSDS for denatured alcohol. MSDS 03200, Revision 2.0 / Revision Date 12/18/01 JC Formula 3 200 Proof / Page 1 of 2 Product Information (xxx) xxx-xxxx / Emergency Assistance (xxx) xxx-xxxx MATERIAL SAFETY DATA SHEETS SECTION I PRODUCT AND COMPANY IDENTIFICATION PRODUCT: Denatured Ethanol, Anhydrous (Prop Solv. #3) This MSDS is valid for all grades and catalog #’s including 123PS3200 and 124003200 Synonyms: Denatured Ethanol Anhydrous, Industrial Alcohol Formula: Mixture Manufacturer: Pharmco Products Inc. 58 Vale Road Brookfield, Connecticut 06804, USA Phone (203) 740-3471 Fax (203) 740-3481 Emergency Contact: CHEMTREC 1-800-424-9300 SECTION II COMPOSITION /INFORMATION ON INGREDIENTS %vol Material CAS Exposure Limits 92.46 Ethanol 64-17-5 1000ppm TWA 3.7 Methanol 67-56-1 200ppm TWA, OSHA/ACGIH;250pp m STEL OSHA/ACGIH 1.9 MIBK 108-10-1 50ppm PEL/OSHA; 50ppm TLV .97 Ethyl Acetate 141-78-6 400ppm TWA .97 Toluene 108-88-3 100ppm TWA/OSHA 150ppm STEL/OSHA SECTION III HAZARDS IDENTIFICATION Carcinogen Status: Established uses of denatured ethanol are not considered to pose a significant cancer hazard. Poisonous: This product contains methanol. It can not be made non-poisonous. Ingestion of 60-200ml of methanol is a fatal dose for most adults. Ingestion of 10ml may cause blindness. Routes of Exposure: Swallowing: May cause dizziness, faintness, drowsiness decreased awareness or responsiveness, nausea, vomiting, staggering gait, lack of coordination, blindness, coma and death. Skin Absorption: Prolonged or widespread contact may result in the absorption of potentially harmful amounts. Inhalation: High vapor concentration may cause burning sensation in nose and throat and stinging and watering in the eyes. At concentrations which cause irritation, dizziness, faintness, drowsiness, nausea and vomiting may also occur. Skin Contact: Prolonged or repeated contact may cause defatting and drying of the skin. Eye Contact: May cause irritation including stinging, tearing, and redness Effects of Repeated Overexposure: Long term repeated oral exposure to ethanol may result in the development of progressive liver injury with fibrosis. Overexposure to methanol may cause eye damage and liver or kidney injury. Other Health Hazards: Repeated ingestion of ethanol by pregnant mothers has been shown to adversely affect the central nervous system of the fetus, producing a collection of effects which together constitute fetal alcohol syndrome. Medical Conditions Aggravated by Overexposure: Repeated exposure to ethanol may aggravate liver injury produced from other causes. Skin contact may aggravate dermatitis. SECTION IV FIRST AID Obtain medical attention for all cases of over-exposure. Swallowing: If patient is fully conscious, give two glasses of water. Induce vomiting. Obtain medical attention. Skin: Wash skin with soap and water for at least 15 minutes Inhalation: Remove to fresh air; Give artificial respiration if not breathing; If breathing is difficult oxygen may be given by qualified personnel; Obtain medical assistance is discomfort persists. Eye Contact: Flush eyes with water for at least 15 minutes. Obtain medical assistance. Note to Physician: Symptoms vary with alcohol level of the blood. Mild alcohol intoxication occurs at blood levels between 0.5-.15%. Approximately 25% of individuals show signs of intoxication at these levels. Above .15% the person is definitely under the influence of ethanol; 50-95% of individuals are clinically intoxicated at these levels. Severe poisoning occurs when the blood is ethanol level is 0.3- 0.5%. Above 0.5% the individual will be comatose and death can occur. The unabsorbed ethanol should be removed by gastric lavage after intubating the patient to prevent aspiration. Avoid the use of depressant drugs or the excessive administration of fluids. SECTION V FIRE FIGHTING MEASURES Fire/Explosive Properties - For Pure 200 Proof Ethanol Flash Point: 58F (14C)Tag Closed Cup Flammable Limits in Air (for ethanol): For pure ethanol: 3.3% - 19.0% Flammability Classification: 3 (NFPA) 1993 Emergency Response Guidebook: Guide 26 (for pure ethanol) 1996 North American Emergency Response Guidebook: Guide 127 (for pure ethanol) Extinguishing Media: Apply alcohol-type or all-purpose foam by manufacturer’s recommended techniques for large fires. Use carbon dioxide or dry chemical media for small fires. Special Fire Fighting Procedures: Use water spray to cool fireexposed containers and structures; Use water spray to disperse vapors - re-ignition is possible; Use self-contained breathing apparatus and protective clothing. Unusual Fire and Explosion Hazards: ¨ Vapors may travel to source of ignition and flash back. ¨ Vapors may settle in low or confined spaces. MSDS 03200, Revision 2.0 / Revision Date 12/18/01 JC Formula 3 200 Proof / Page 2 of 2 ¨ May produce a floating fire hazard. ¨ Static ignition hazard can result from handling and use. SECTION VI SPILL/ACCIDENTAL RELEASE MEASURES Small spills can be flushed with large amounts of water. Large spills: Eliminate all ignition sources; ground all equipment; do not walk through spill; stop spill if possible; prevent entry into sewers, confined spaces, etc.; use a vapor suppressing foam to reduce vapors; absorb spill with noncombustible matter and transfer to containers; use nonsparking tools to collect absorbed material. Refer to Section 11 for disposal information. SECTION VII HANDLING AND STORAGE ¨ Flammable material - keep away from heat, sparks, and flame; sudden releases of hot organic vapors or mists from process equipment operating at elevated temperature may result in ignitions without the presence of obvious ignition sources. ¨ Avoid contact with eyes. ¨ Keep container closed. ¨ Use with adequate ventilation. ¨ Ground container when transferring product. ¨ Vapors may collect in containers; treat empty containers as hazardous. ¨ Wash thoroughly after handling ¨ Vapors may settle in low or confined areas ¨ Danger - may cause blindness or death if swallowed SECTION VIII EXPOSURE CONTROLS / PERSONAL PROTECTION Ventilation: Special, local ventilation is needed where vapors escape to the workplace air Respiratory Protection: Use self-contained breathing apparatus in high vapor concentration Personal Protective Equipment: gloves, lab coat or uniform, safety glasses, eye wash, safety shower SECTION IX PHYSICAL AND CHEMICAL PROPERTIES Appearance: clear, colorless liquid Odor: characteristic Characteristics for 200 Proof Ethanol: Vapor pressure @ 20C: 44.6mm Hg Vapor density: 1.6 (air =1) Boiling point @ 760mm Hg: 78.3 C (172.9F) Freezing Point: < -114.1C (<-173.4F) Solubility in Water: 100% @ 20C Density @ 15.56C (60F) 6.6lbs/gal Evaporation Rate: 3.0 (butyl acetate = 1) Percent Volatiles: 100% Specific Gravity : .796 @ 15.56 SECTION X STABILITY/REACTIVITY INFORMATION Stability: Stable Conditions to avoid: None known Incompatibility/Materials to avoid: strong oxidizing agents; strong inorganic acids Hazardous Combustion/Decomposition Products: Carbon monoxide and/or carbon dioxide Hazardous Polymerization: Will not occur SECTION XI DISPOSAL CONSIDERATIONS Vapors may collect in empty containers. Treat empty containers as hazardous. Dispose of spill-clean up and other wastes in accordance with Federal, State, and local regulations. SECTION XII TRANSPORTATION INFORMATION Proper Shipping Name: Alcohol, nos Hazard Class: 3 UN Number: 1987 IMO Information: Alcohols, NOS Label of Class: 3 Packing Group II Intermediate flashpoint group SECTION XIII REGULATORY INFORMATION Federal EPA Comprehensive Environmental Response Compensation, and Liability Act of 1980 (CERCLA) requires notification of the National Response Center of release quantities of Hazardous Substances equal to or greater than the reportable quantities (RQs) in CFR. Components present in this product at a level which could require reporting under this statute are: Chemical CAS Number Upper Bound Conc. % MIBK 108-10-1 1.9 Methanol 67-56-1 3.7 Acetaldehyde 75-07-0 .0010 Toluene Ethyl Acetate 108-88-3 141-78-6 .97 .97 Superfund Amendments and Reauthorization Act of 1986 (SARA) Title III requires emergency planning based on threshold planning quantities and release reporting based on reportable quantities in 40 CFR 355 (used for SARA 302, 304, 311, and 312). Components present in this product at a level which could require reporting under this statute are: none. Superfund Amendments and Reauthorization Act of 1986 (SARA) Title III requires submission of annual reports of release of toxic chemicals that appear in 40 CFR 372 (for SARA 313). This information must be included in all MSDS’s that are copied and distributed for this material. Components present in this product at a level which could require reporting under the statute are: Methanol (67-56-1) upper bound concentration 3.7% Toxic Substances Control Act (TSCA) Status: The ingredients of this product are on the TSCA inventory. State Right to Know California Proposition 65: This product contains trace levels of acetaldehyde known to the State of California to cause cancer. This product contains toluene which the State of California has found to cause birth defects or other reproductive harm. Massachusetts: Hazardous substances and extraordinarily hazardous substances must be identified. Components present which could require reporting: Extraordinarily Hazardous (=> 0.0001%): Acetaldehyde (CAS 75-07-0) upper bound conc. .0010% Hazardous (=>1%): Ethanol (CAS 64-17-5) upper bound conc. 92.46% Methanol (CAS 67-56-1) upper bound conc. 3.7% Pennsylvania: Hazardous substances must be identified. Hazardous (=>1%): Ethanol (CAS 64-17-5) upper bound conc. 92.46% Methanol (CAS 67-56-1) upper bound conc. 3.7% California SCAQMD Rule 443.1 (VOC’s) A Volatile Organic Compound (VOC) is any volatile compound of carbon excluding methane, carbon monoxide, carbonic acid, metallic carbides, or carbonates, ammonium carbonate, 1,1,1 tri-chloroethane, methylene chloride, (FC-23), (CFC-113), (CFC-12), (CFC-11), (CFC-22), (CFC- 114) and (CFC-115). VOC 800g/l; vapor pressure 41.4 mm Hg @20C for pure 190 proof ethanol The information contained herein is based on data considered to be accurate. However, no warranty is expressed regarding the accuracy of these data or the results to be obtained from the use thereof. It is the user’s obligation to determine the conditions of safe use of the product. 9bc13a994de122c6c8cc31ced1cbda71f05e5a47 0 475 1101 1100 2013-05-12T02:54:39Z Jsfisher 1 1 revision wikitext text/x-wiki There are literally thousands of articles about holography in the technical journal. One day we hope to list them here. 7d0c9342fe823dd60f8665bbef4b30a2e931d93c 0 476 1103 1102 2013-05-12T02:54:40Z Jsfisher 1 1 revision wikitext text/x-wiki The refractive index is a dimentionless quantity that measures the speed of light in the material. It is defined as the ratio of the speed of light in a vacuum to the speed of light in the material and is usually signified by the letter n. n=c(vacuum)/c(mat) ==Mixing Two Chemicals to Get a new Refractive Index== If you need a different refractive index two '''compatible materials''' can be mixed the new refractive index would be: P1/100 = (n(new) - n2) / (n1 - n2) where P1 denotes the volume percent of component 1, n1 is the index of component 1, n2 that of component 2, and n(new) that of the mixture. (Hanz Bjelkhagen). ==Choosing the best Refractive Index== The optimum Refractive Index for matching two materials is given by the equation (the geometric mean): n(optimum)=sqrt((n0)(n1)) Large deviations are posible so don't kill youself trying to get the exact one. ==Refractive Indices== Here are some available index matching fluids for reference (could be helpful for liquid filled lenses as well). There are some scary chemicals here so get the MSDS before you use them and follow all recomended procedures: *Methyl Alcohol 1.328 *Water 1.335 *Freon-113 1.358 *Gelatin 1.36 (8 grams in 50 ml of water) *Paraffin (Lamp Oil) about 1.4 *l-Butanol, 3 methyl 1.405 *Kodak Dispersant MX-1320 1.420 *Stoddard Solvent 1.435 *Methyl Chloroform 1.438 *Kerosene 1.460 *Carbon Tetrachloride 1.461 *Decalin Solvent 1.475 *Glycerin 1.475 *Mineral Oil 1.475 *Trichloroethene 1.494 *Tetrachloroethane 1.494 *Diethylbenzene 1.496 *Toluene 1.496 *p-Xylene 1.496 *Di-n-butyl phthalate 1.497 *Xylene (commercial) 1.499 *Glass (common) 1.5 *Tatrachloroethylene 1.504 *o-Xylene 1.506 *Pyridine 1.509 *Dimethylphthalate 1.515 *Benzyl ether 1.517 *b-Ionone 1.520 *Ethyl benzoil acetate 1.523 *Chloro benzene 1.524 *Methyl salicylate 1.536 *Benzyl benzoate 1.570 *Bromo naphthalene 1.658 Refractive index shown at 20C. From Silver-Halide Recording Materials for Holography and Their Processing by H.I. Bjelkhagen except Paraffin, glass, water and gelatin ca23097cddbc111c5c5093db69e739baca8ff262 0 477 1105 1104 2013-05-12T02:54:40Z Jsfisher 1 1 revision wikitext text/x-wiki ==Bleaching with Rehalogenating Bleach== by Jeff Blyth A successful bleach for reflection Holograms comes from using: '''60KB Rehalogenating Bleach''' *40g Ethylenediaminetetraacetic acid iron (111) sodium salt [Aldrich cat. No. 35,961-0] *60g. potassium bromide & *70 ml acetic acid Dissolved up in 1 litre water (tap water is OK here). This bleach is particularly good after a developer such as [[TJ1_Developer]] is used. ===Theory=== So what happens with in this type of bleach used WITHOUT FIXING (i.e.without removing unexposed AgBr) in thiosulfate, is that the developed up silver gets re-oxidized to AgBr. But instead of returning you to square one and leaving you with a uniform coating and distribution of AgBr again just as it was before you exposed it, it is energetically more favorable for the re-made AgBr to move over to the adjacent dark fringe made up of virgin AgBr and grow onto that dark fringe using the virgin AgBr grains as seeding centers. That actually requires the bleach solution to have some AgBr solvation ability to enable this carry-over effect to occur. This effect occurs with the help of the relatively high concentration of potassium bromide present because it does raise the solubility of AgBr in the solution through the formation of complexes. Now the great thing about this carry-over effect is that it causes almost all the original Ag in the emulsion to build up the fringes whereas if you had had to use fix you would have removed about half of your original silver content in the thiosulfate solution. A revealing experiment is to take a newly developed plate that has been in a stop bath of ~5% acetic acid, rinse it and then place it upright in a beaker so that it is half covered in a fix solution such as 20% sodium thiosulfate. After giving it gentle agitation over about 4 -5 minutes avoiding splashing the unimmersed half it is then all given a vigorous rinse under tap water. Then the whole plate is immersed in the above bleach formula and given constant agitation. The first interesting thing that will be seen is that the fixed half will take longer to bleach the dark silver than the unfixed half . This is at first counter-intuitive since one would expect that initially removing the undeveloped AgBr in the fix would later have left the bleach plenty of spare room in the gelatin to react and oxidize the silver metal without being encumbered by lots of AgBr still present. The second point that will be noticed is that when the whole plate is bleached there will be considerable scatter on the fixed half compared to the unfixed half. The increased scatter in the fixed half also testifies to the truth of that carry-over mechanism. The scatter is a consequence of the carry-over effect being unable to operate because of the missing virgin AgBr. Therefore the newly formed AgBr builds up around the dissolving silver grains in solution before reaching a level where it becomes energetically favorable to precipitate out. The precipitate will be in larger grains and to some extent will occur in the dark fringe areas where the gelatin is supposed to be free of AgBr in order to give good fringe contrast with the new AgBr in the light fringes. The finished hologram if it had been recorded in red will now be shifted to the green, scattery, and less bright than the unfixed half. ===Bleaching Transmission Holograms=== The formulation above has been found to work pretty well also with transmission Holograms (Hs). The not-so-good thing about it though is that the original sensitizing dyes become chemically locked into AgBr grains making the emulsion very vulnerable to print out, i.e. darkening slowly in ambient lighting, particularly sunshine. The dyes can be chemically inactivated with a 2% potassium or ammonium dichromate bath-- it takes about a minute after you have used the Ferric EDTA bleach. ===A Good Bleach for Transmission Holograms, (can also be used to make reflection ones with a shorter replay wavelength)=== A better bleach for transmission holograms is to dissolve up 0.5 to1 gram of iodine crystals in about 200 ml alcohol (methanol or ethanol) and then about 200ml of water is added. However before putting the plate in, it is essential this time to use fix. This is because the bleach has no carry-over power. The fix bath can be 20% sodium thiosulfate and the plate given about 4 minutes in it with mild agitation. It is then given a thorough rinse under tap water to remove all traces of fix. After the bleach step the iodine stain can be removed in a 70% alcohol bath. A very good point about this bleach is that the dyes are released by the fix and easily removed in the alcoholic iodine solution. A comparison was made by cutting a developed and stopped (5% acetic acid) transmission H in half and then bleaching one half in the ferric-EDTA bleach and the other half after fixing was put in the iodine bleach. The iodine bleached half finished up producing a slightly higher diffraction efficiency. (This could be due to the carry-over effect being less efficient in the larger fringe spacing of transmission Hs compared to reflection Hs.) If you choose to use this bleach on say a '''reflection hologram''' made with a red laser then you can get a quite nice final yellow-green replay color because contraction occurs due to loss of the original virgin AgBr in the fix solution. (You also get a little bit of expansion due to AgI replacing AgBr.) It may then look brighter than a red one would have looked because of the eye's extra sensitivity to light-green even though some valuable AgBr diffracting material has been lost ===References=== P. Hariharan, C.M. Chidley; Rehalogenating Bleaches for photographic phase holograms 2: spatial frequency effects. Appl. Optics. 27 No.18, 3852 (1988) ) 5e0c98d115c38a2527d85fc56af04c73e5eca7d5 0 478 1107 1106 2013-05-12T02:54:41Z Jsfisher 1 1 revision wikitext text/x-wiki ==The Reversal Bleach system== by Jeff Blyth The most popular form of this type originally used dichromate salt and sulfuric acid. It has been of particular value for use on the AGFA 8E75 HD plates and film because when used correctly it can produce the lowest levels of light scatter. Its popularity for Denisyuk reflection holograms made with 633nm from HeNe lasers also comes from the inclination to hit the fairly elusive yellow replay coloration due to the right amount of emulsion shrinkage. I consider that its chief asset today with finer grain materials available is as a bleach for transmission holograms. It has good printout resistance (i.e. low tendency to darken in ambient lighting over time) and can produce high diffraction efficiency. However for Denisyuk reflection holograms it does not achieve as much diffraction efficiency as can be obtained from a good rehalogenating bleach. People using it have however failed to appreciate that the developer used beforehand should not contain silver halide solvents such as sodium sulfite and urea, and the need for the rigorous exclusion of halide contaminants as discussed in the Theory section. A suitable developer for use in conjunction with this bleach is [[TJ1 Developer]]. The proportions used in the formulation is hugely tolerant of variation. I have chosen to use a lower concentration of dichromate compared to previous publications because it leaves the bleached hologram with less yellow coloration from the dichromate salt and this means less rinsing is required to remove it. Increasing the dichromate proportion will reduce the time taken to bleach the dark silver. I have substituted sulfuric acid with the more manageable solid salt sodium hydrogen sulfate. (This is in fact a semi-neutralized form of sulfuric acid). The basic formula is: *1 g. potassium dichromate (or ammonium dichromate) *10g sodium hydrogen sulfate. *made up to 1 litre in distilled or de-ionized water. The set up should include 2 baths of de-ionized water (DI) as follows: '''Bath 1''' *DI with *4% acetic acid (Acts as a “Stop” to stop developer action) '''Bath 2''' *DI '''Bath 3''' *Reversal Bleach ==Procedure== #After development, a brief 10 second rinse under running tap water then a good rinse in Bath 1. for ~1 minute . #A good rinse in Bath 2. ~1 minute #Immerse in Reversal bleach (Bath 3) and gently agitate until no dark silver remains #Important- after the bleach bath the hologram should be put first back in DI (Bath 2) for ~ 20 sec. before being rinsed under tap. ==Theory== The idea might seem simple enough, after development the developed up silver is dissolved up into the solution and removed from the gelatin film so that then leaves the undeveloped virgin AgBr in the dark fringes to make the hologram. So in effect it both “fixes” and bleaches. The good point about it is that it has a high resistance to printout or darkening in ambient light and can have low scatter levels with holographic plates that do not have the smallest AgBr grains such as the old Agfa material, the lowest scatter comes about provided you understand what you must do to stop any soluble halide ions getting into your hologram before you have finished processing. ==Developer considerations== Because of the way this bleach operates, particular consideration has also got to be given the developer system used first. It is not satisfactory to have any “physical development “ which encourages silver bromide to be dissolved in the developer. We need to have as much virgin AgBr as possible to create our final diffraction and it makes no sense to load up the developer with sulfite ion­ a weak silver halide solvent and similar remarks apply to urea as in the CW developer. The amount of development is also more important than in the case of the rehalogenating bleach system. Since all the developed silver is going to be washed away, if you develop too much for too long then you start to eat into your virgin AgBr in the dark fringes because even unexposed AgBr is developable given enough time. The consequence is that reflection holograms made with red lasers may look a dull green instead bright yellow/green due to increased contraction . This effect has also been shown to cause a peak in the graph of diffraction efficiency vs. developer/exposure level and after the peak the efficiency drops away. Whereas when a rehalogenating bleach is used after the same developer conditions, the diffraction efficiency flattens off. [Joly] ==Importance of De-ionized rinsing water.== After the developer the hologram needs a good rinse under tap water to remove the developer and soluble bromide and iodide ions in it . Even if the developer had no halide ions initially, the development process means that the AgBr and AgI in the emulsion had to be broken up and turned into dark silver and soluble Br- and I-. The tap water rinse then leaves the emulsion with just chloride ions from tap water which are less of a problem to deal with later than soluble bromide or iodide ions. Before the dichromate bath is used you have to have two pre-baths of de-ionized water (DI) to remove all traces of dissolved halide ions. If you don’t do this then some of the developed up silver fails to be removed from the light-struck fringes and deposits itself back in the fringe as silver halide. This causes scatter in the finished hologram and reduces diffraction efficiency because the light struck fringes have failed to be properly cleared of AgBr . Where even experienced holographers commonly go wrong is that after removing the bleached hologram from this reversal bleach bath, they rinse it under the tap instead of first putting the hologram back in de-ionized water for a second time . This is because after leaving the bleach bath the hologram is full of silver ions in solution which can instantly form silver chloride particles with the chloride ions in tap water. So this causes scattering from inside the emulsion which cannot be wiped away even if surface silver chloride can be. After using the bleach bath you may notice a red-brown precipitate or scum in the bath. This is normal and it is actually good to have it in there. It is made up of silver chromate or dichromate which is not very soluble but is far more soluble than are the silver halides. So what this red sludge means is that your bleach bath is saturated with silver chromate in solution and any stray halide ions in solution are effectively precipitated out before they can get inside your emulsion. Even though some precipitated silver chromate may form in your gelatin layer it comes out easily in the DI bath. After this final DI bath you can then rinse the hologram in tap water to eliminate any dichromate ions if you wish, because there will be no soluble silver ions to cause trouble in a final tap water rinse. (Personally I like having a trace of dichromate in the hologram not washed out because it helps to prevent future printout. However dichromate is quite poisonous and who knows what future use your hologram may be put to particularly with young children around). ==Tap water rinsing== Prolonged tap water rinsing can remove some of your AgBr with significant differences depending on time of year and the temperature of your cold water supply. Any AgBr loss causes a shift to a shorter wavelength replay in the case of reflection holograms and of course some loss in diffraction efficiency but sometimes people prefer to simply shift the color from orange-yellow to yellow-green using a hot water rinse. The result can look brighter, also any scatter from AgCl contamination can be removed because AgCl is about ten times more soluble than AgBr. Some idea of the temperature effect can be seen from this graph: [[Image:SilverSolubility.gif]] ==References== [Joly L., Jacobs P. Spectral Response of reflection gratings on Holotest 8E75 HD Proc. Int’l Symp. on Display Holography, ed. Jeong, T.J. Lake Forest College IL. Vol III p115-126 (1989).] [Owen, B.B. and Brinkley, S.R. J.A.C.S. 60, 2237 (1938).] e75fa688214d0f9739dcc8f1b19b689401b54caa 0 479 1109 1108 2013-05-12T02:54:41Z Jsfisher 1 1 revision wikitext text/x-wiki This is a stub *A great description of DPSS ring lasers can be found in [http://www.holographyforum.org/files/holopdfs/DPSSThesis.pdf Christoph Boling's Thesis]. e97f48dfe4784e3bb475906b946eb7ab87e3e681 0 480 1111 1110 2013-05-12T02:54:41Z Jsfisher 1 1 revision wikitext text/x-wiki A proper rinse is very important for making good holograms. There are a few things to consider. The first is the length of the rinse. A good rinse is long enough to remove all of active chemicals. 5 minutes is often used. ==About Water== Water is more than just H2O. Tap water starts as rain fall. This water filters down through the ground to an aquifer. From the aquifer it either comes up through a spring or is pumped up through a well. This path disolves many things into the water. Gypsom, Epsom, Calcium Chloride and salt are often encountered. Also, it is common for water to disolve traces of iron on the way to the tap. Ions in Tap Water: *Ca++ Calcium *Mg++ Magnesium *Na+ Sodium *Cl- Cloride *SO4-- Sulfate *HCO3- Hydrogen Carbonate and to a lesser extent H2CO3 and CO3--. It can also contain disolved CO2 as carbonic acid. ==Tap water rinsing== By Jeff Blyth Prolonged tap water rinsing can remove some of your AgBr with significant differences depending on time of year and the temperature of your cold water supply. Any AgBr loss causes a shift to a shorter wavelength replay in the case of reflection holograms and of course some loss in diffraction efficiency but sometimes people prefer to simply shift the color from orange-yellow to yellow-green using a hot water rinse. The result can look brighter, also any scatter from AgCl contamination can be removed because AgCl is about ten times more soluble than AgBr. Some idea of the temperature effect can be seen from this graph: [[Image:SilverSolubility.gif]] ==Importance of De-ionized Rinsing Water when "reversal" bleach is used.== By Jeff Blyth If you are using a rehalogenating bleach then tap water alone is OK but with reversal bleach it is really important to avoid soluble halide ions (ie. bromide,chloride or iodide ions) remaining in your hologram before it goes into the dichromate bleach bath. So the procedure should be: After the developer the hologram needs a good rinse under tap water to remove the developer and soluble bromide and iodide ions in it . Even if the developer had no halide ions initially, the development process means that the AgBr and AgI in the emulsion had to be broken up and turned into dark silver and soluble Br- and I-. The tap water rinse then leaves the emulsion with just chloride ions from tap water which are less of a problem to deal with later than soluble bromide or iodide ions. Before the dichromate bath is used you have to have two pre-baths of de-ionized water (DI) to remove all traces of dissolved halide ions. If you don’t do this then some of the developed up silver fails to be removed from the light-struck fringes and deposits itself back in the fringe as silver halide. This causes scatter in the finished hologram and reduces diffraction efficiency because the light struck fringes have failed to be properly cleared of AgBr. Where even experienced holographers commonly go wrong is that after removing the bleached hologram from this reversal bleach bath, they rinse it under the tap instead of first putting the hologram back in de-ionized water for a second time. This is because after leaving the bleach bath the hologram is full of silver ions in solution which can instantly form silver chloride particles with the chloride ions in tap water. So this causes scattering from inside the emulsion which cannot be wiped away even if surface silver chloride can be. After using the bleach bath you may notice a red-brown precipitate or scum in the bath. This is normal and it is actually good to have it in there. It is made up of silver chromate or dichromate which is not very soluble but is far more soluble than are the silver halides. So what this red sludge means is that your bleach bath is saturated with silver chromate in solution and any stray halide ions in solution are effectively precipitated out before they can get inside your emulsion. Even though some precipitated silver chromate may form in your gelatin layer it comes out easily in the DI bath. After this final DI bath you can then rinse the hologram in tap water to eliminate any dichromate ions if you wish, because there will be no soluble silver ions to cause trouble in a final tap water rinse. (Personally I like having a trace of dichromate in the hologram not washed out because it helps to prevent future printout. However dichromate is quite poisonous and who knows what future use your hologram may be put to particularly with young children around). ==Filtration Systems== Filtration is a good way to make large quanities of water at a known quality. There are many filter types. ===Charcoal=== Charcoal filtration passes water through activated charcoal. Charcoal is activated by using Oxygen to open millions of tiny pores in the carbon structure. The resulting surface area can exceed 1000 M^2 per gram! A charcoal filter works by adsorbing impurities it is effective in removing chlorine and carbon based molecules. '''Advantages''' *Inexpensive *Commonly Available *Removes Chlorine '''Disadvantages''' *Will not remove Nitrates or salts ===Ion Exchange=== Ion Exchange uses salt to take out all of the ions in water and replace them with Na+ and Cl- ions. Also called water softeners. These are not very suitable to rinse water. '''Advantages''' *Removes all of the Ca++ and Mg++ ions. *Inexpensive compared to DI units. *Removes upto 10 ppm of Fe. '''Disadvantages''' *Must be flushed with water daily. *The salt must be replaced frequently. *Adds lots of Na+ and Cl- ions to the water. *Leaves chlorine intact. ===Deionization=== These filters usually use a mixed bed ion exchange unit. It provides very pure water. The cartridges must be recharged by washing the ions from them. Most often they are replaced. Usually a Carbon filter and/or a softener are used ahead of a DI unit. '''Advantages''' *Very pure water. *High flow rates. '''Disadvantages''' *Medium installation costs. *Expensive to recharge and replace cartridges. ===Reverse Osmosis=== Small RO systems usually consist of 3 or 4 filters. A coarse filter, a fine filter, a charcoal filter and a membrane filter. It is the function of the last filter that gives this system it's name. In order to operate much water is used for providing the osmotic pressure. It is not unheard of to have 2 gallons of waste water for each gallon of RO water. RO units are slow to produce water so they usually have a storage tank to hold water made in off peak times. '''Advantages''' *Filters all ions to around 5ppm or better. *Filters almost all impurities. '''Disadvantages''' *Wastes lots of water. *Filter replacement is expensive. *Requires a storage tank. *Expensive ===Distillation=== Distillation evaporates water and condenses it on a cool surface leaving all of the impurities behind. It provides the purest water in a lab. '''Advantages''' *Provides the most pure water. '''Disadvantages''' *Expensive. *Low flow rates. *High energy costs. 3ffa5507f658854aa6860dc193ce38537b9367ad 0 481 1113 1112 2013-05-12T02:54:41Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:RLakes.jpg]] [[http://silver.neep.wisc.edu/~lakes/ Rod's Website]] *Columbia University, Mathematics, 1964, 1965 *Rensselaer Polytechnic Institute, B.S., 1969; Ph.D., 1975 *Yale University, Research Associate, 1975 -1977 Applications of holography: experimental mechanics Lakes, R. S., Gorman, D., and Bonfield, W., "Holographic screening method for microelastic solids", J. Materials Science, 20 2882-2888 (1985). Classical elastic and Cosserat elastic materials may be quickly distinguished via holographic study of displacement of a notch at the corner of a square section bar in torsion. Chen, C. P. and Lakes, R. S., "Holographic study of conventional and negative Poisson's ratio metallic foams: elasticity, yield, and micro-deformation", J. Materials Science, 26, 5397-5402 (1991). This article presents an experimental study by holographic interferometry of the following material properties of conventional and negative Poisson's ratio copper foams: Young's moduli, Poisson's ratios, yield strengths, and characteristic lengths associated with inhomogeneous deformation. The Young's modulus and yield strength of the conventional copper foam were comparable to those predicted by microstructural modelling on the basis of cellular rib bending. The re-entrant copper foam exhibited a negative Poisson's ratio as indicated by the elliptic contour fringes on the specimen surface in the bending tests. Inhomogeneous, non-affine deformation was observed holographically in both foam materials. Download pdf Lakes, R. S. and Elms, K., "Indentability of conventional and negative Poisson's ratio foams", J. Composite Materials, 27,1193-1202, (1993). The indentation resistance of foams, both of conventional structure and of a novel re-entrant structure giving rise to negative Poisson's ratio, was studied using holographic interferometry. In holographic indentation tests, re-entrant foams had higher yield strengths sigma y and lower stiffness E than conventional foams of the same original relative density. Damage in both kinds of foam occurred primarily directly under the indenter. Calculated energy absorption for dynamic impact is considerably higher for re-entrant foam than conventional foam. Chen, C. P. and Lakes, R. S., "Holographic study of non-affine deformation in copper foam with a negative Poisson's ratio -0.8", Scripta Metall et Mater., 29, 395-399, (1993). Negative Poisson's ratio copper foam (Poisson's ratio -0.8) with a permanent volumetric compression ratio of 2.2 exhibits a greater non-affine (inhomogeneous) deformation than either conventional foam or negative Poisson's ratio foam (Poisson's ratio = -0.1) with a volumetric compression ratio of 3. Anderson, W. B., Lakes, R. S., and Smith, M. C., "Holographic evaluation of warp in the torsion of a bar of cellular solid", Cellular Polymers, 14, 1-13, (1995). Holographic methods are utilized to examine deviations from classical elasticity in a cellular solid, polymethacrylamide closed cell foam. A square cross section bar is subjected to static torsional deformation. The warp deformation is observed to be less in a foam bar than in a homogeneous polymeric bar used as a control. The homogeneous bar obeys the predictions of classical elasticity. Behavior of the foam bar is consistent with Cosserat elasticity. In a Cosserat solid, points in the continuum to rotate as well as translate, and the material supports couple per unit area as well as force per unit area. Cosserat effects can lead to enhanced toughness. This image shows holographic fringes associated with warp. Development of holographic methods Lakes, R. S., "Multi wavelength techniques in holographic interferometry", Journal of Modern Optics, 35(9), 1459-1465 (1988). Techniques are presented which take advantage of the wavelength dependence of various phenomena in holographic interferometry. Image-plane interferograms illuminated with light containing multiple wavelengths exhibit color dispersion of the fringes. We extract from this dispersion, full- field information concerning displacement components which are not disclosed by monochromatic illumination. Cohen, B. and Lakes, R. S., "Aberration reduction in one step lens image plane holography", Applied Optics, 27, 3322-3323 (1988). A simple correction scheme is presented, which permits the use of large aperture lens systems of modest quality, even single element lenses, to produce image plane holograms viewable in white light. The present method allows white light reconstruction and corrects field curvature, which is the most objectionable aberration in display holograms. The field curvature was corrected by making the hologram with diverging light and illuminating the hologram with collimated light to introduce a compensating negative curvature of field. Wuest, D. and Lakes, R. S., "Color control in reflection holograms by humidity", Applied Optics, 30, 2363-2367 (1991). A method is presented which permits control of the reconstruction wavelength of reflection holograms and holographic optical elements [HOE's]. This approach makes use of developer and bleach which minimize emulsion shrinkage combined with control of ambient humidity to control the emulsion shrinkage during formation and reconstruction. A simple index matching approach to the elimination of the wood grain effect in reflection holograms is also presented. Applications: Holographic Optical Elements Wadle, S. and Lakes, R. S., "Holographic diffusers: polarization effects", Optical Engineering, 33, 1084-1088, (1994). In some applications of diffusers, it is desirable to minimize the diffuse back reflection of light. Use of polarized light is one way to reduce this back reflection. To that end, the effect of diffusers upon polarized light is studied experimentally. Diffusers based on ground glass, white plastic containing scatterers, and holographic optical elements are considered. The ground glass and HOE diffusers preserve polarization in the diffusion process, but the white plastic does not. Diffuse back reflection from ground glass or holographic diffusers can be significantly reduced by the use of an isolator based on a quarter wave plate. Wadle, S., Wuest, D., Cantalupo, J., and Lakes, R. S., "Holographic diffusers", Optical Engineering, 33, 213-218, (1994). Holographic diffusers were prepared using silver halide (Agfa 8E75 and Kodak 649F) and photopolymer (Polaroid DMP128 and DuPont 600, 705, and 150 series) media. It was possible to control the diffusion angle in three ways: by selection of the properties of the source diffuser, by control of its subtended angle, and by selection of the holographic medium. Several conventional diffusers based on refraction or scattering of light were examined for comparison. Wuest, D. and Lakes, R. S., "Holographic optical element for projection of stereo images", Applied Optics, 31, 1008-1009 (1992). We present a holographic element capable of projecting dynamic stereo images, and allowing the observer to see through the device, for possible use as a head up display in aircraft. The device is based on a volume reflection holographic optical element which contains two sets of Bragg planes. Each set of Bragg planes diffracts light from a two-dimensional source to the appropriate eye to achieve a stereo effect. Lakes, R. S. and Vick, G., "Partial collimation of light from a diffusely reflective source", J. Modern Optics, 39, 2113- 2119, (1992). A general purpose collimator capable of collimation of radiation from an arbitrary thermal source of diffuse light is incompatible with the second law of thermodynamics. However there are 'special purpose' collimators which would not be generally applicable. A new collimator which is effective when placed close to a white (diffusely reflective) source is presented. Wadle, S. and Lakes, R. S., "Holographic diffusers with low back-scatter", J. Modern Optics, 42, 1387-1396, (1995). Holographic diffusers have been produced with very low back diffusion in comparison with diffusion in the forward direction. Reduced back diffusion was achieved by lamination and index matching procedures which minimized the formation of Bragg planes parallel to the film surface. Photopolymer media were used as phase media. Diffusers with the lowest values of back diffusion were prepared by moderately restricting the field angle of incident light during formation. 9a8ab2dc30f42f98e478de8102593954aa0be29d 0 482 1115 1114 2013-05-12T02:54:42Z Jsfisher 1 1 revision wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 483 1117 1116 2013-05-12T02:54:42Z Jsfisher 1 1 revision wikitext text/x-wiki '''Ruby''' - Chromium doped aluminum oxide (Cr:Al2O3) ====Physical Properties==== *Specific Gravity 3.9 to 4.1 *Hardness 9 *Refractive Index 1.76-1.77 *Fluorescent Lifetime 3.0ms at 300K *Spectral Linewidth 11cm^-1,5.3A *Major Pump Bands 404nm and 554nm *Doping Level .05% by wt. '''TECHNICAL DATA PROPERTIES OF SYNTHETIC SAPPHIRE & RUBY ''' *Chemical Formula: AL 2 0 3 (monocrytalline/hexagonal) *Density: 0.143 lb/in 3 (3.97 gm/cm 3 ) *Specific Gravity: 3.97 *Tensile Strength: 60,000 psi (2600 kg/cm 2 ) min @ 25° *Compressive Strength: 350,000 psi (21,000 kg/cm 2 ) *Modulus of Rupture: 67,000-95,000 psi (4000-7000kg/cm 2 ) *Modulus of Rigidity: 25 x 10 6 psi (19,000 kg/mm 2 ) *Young's Modulus: 51 x 10 4 psi *Hardness: 9 (MOHS) /1800?2200 (KNOOP) / 2500-3000 (VICKERS) *Poisson's Ratio: 0.28 ? 0.33 *Coefficient of Friction: 0.14 (Dry Friction on Steel) *Porosity: 0 % '''THERMAL''' *Melting Point: 3725 0 F (2053 0 C) *Specific Heat: 0.18 cal/g 0 C *Thermal Conductivity: 0.09 cal/sec?cm 0 C *Maximum Operating Temperature: 3632 0 F (2000 0 C) *Coefficient of Thermal Expansion: 4.8?5.3x10 -6 cm/cm 0 C '''ELECTRICAL''' *Electrical Resistivity: 10 16 ohm?cm (@25 0 C) *Dielectric Strength: 480,000 volt/cm (@60 Hz) *Dielectric Constant: 8.5 ? 10.5 (300 KHz ? 1 GHz) *Dielectric Loss Tangent: < 0.0001 [http://www.roditi.com/Laser/Ruby.html Ruby Specs] de510e1c5d9cea22179d5fc362009765a4139764 0 485 1121 1120 2013-05-12T02:54:42Z Jsfisher 1 1 revision wikitext text/x-wiki [http://rudieberkhout.home.mindspring.com/home.htm Rudie Berkhout] Rudie Berkhout was a Artist/Holographer from Leeds NY. He had an extensive list of publications about holography and regularly exhibited his work. Born in Amsterdam, Berkhout came to the United States in 1974 with a background in engineering and lighting to study at the New York School of Holography. He later researched white light holographic techniques and pulsed holography at the New York Art Alliance laboratories. He created the first flat display system for holographic movies (Integral holography or holographic stereograms first developed by Lloyd Cross) while at the Holographic Film Company in New York (founded by cinematographer Hart Perry). Until this time, holographic stereograms had been viewed only in the round. Berkhout also designed and built a time-lapse recording system to enable artists to capture as much as four hours of movement in a single hologram. A major contribution to the medium was his work in color control and image multiplication which resulted in his breathtaking "Twelve Milliwatt Boogie" first exhibited in 1979 at the Museum of Holography, New York. This stunning piece set a standard in white-light transmission holography with its boldly-colored geometric figures floating in three-dimensional space. Rudie Berkhout passed away from a heart attack on Tuesday 16 September, 2008. 12495e5074373e7c65f22444dd5c9c44ed7bd6e4 0 486 1123 1122 2013-05-12T02:54:43Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Sabattier effect''' - part positive part negative effect formed when an emulsion is briefly re-exposed to white light during development, and then allowed to continue development. Also known as pseudo-solarization. *'''Safelight''' - darkroom light of a color and intensity that will not affect light sensitized photographic materials. *'''Safety film''' - term used to describe a film with a base that is not readily inflammable. *'''Scale''' - linear relation between the size of the subject and the size of its image. *'''Scanning electron microscope''' - device used in photomicrography. *'''Schumann plate''' - plate coated with an emulsion with so little gelatin content that the silver halide grains protrude above its surface. Used for photography in the ultraviolet region. *'''Screening''' - conversion of a continuous tone image to a half-tone image. *'''Screen plate''' - plate used in early additive forms of color photography. *'''Scrim''' - lighting attachment which, when placed in front of a lamp, reduces its strength, usually by one stop, without affecting lighting quality or color. *'''Selective focusing''' - method of adjusting the lens aperture and shutter speed to give a depth of field that will limit image sharpness to a particular area of the image. *'''Selenium''' - light-sensitive substance which, when used in a barrier-layer construction, generates electrical current when exposed to light. Used in exposure meters and dry copy film. *'''Selenium cell''' - light sensitive cell used in many types of exposure meters. It generates electricity in direct proportion to the amount of light falling upon its surface. *'''Self-timer''' - mechanism for delaying the opening of the shutter for a given number of seconds after the release has been operated. *'''Self toning paper''' - obsolete silver chloride paper used for contact printing in daylight. *'''Sensitive material''' - in photography, refers to materials that react to the actinic power of light. *'''Sensitivity''' - degree of response of a photographic emulsion to exposure to light. *'''Sensitometry''' - scientific study of the response of photographic materials to exposure and development. It establishes emulsion speeds and recommended development and processing times. *'''Separation images''' - technique of producing an image by combining photographs produced on a material or using equipment which is sensitive to one region of the visible spectrum. *'''Separation negatives''' - black & white negatives, usually prepared in lots of three or four, which have been taken through filters which analyze the color composition of an original in terms of blue, green and red. They are used particularly in photomechanical color printing and dye transfer printing processes. *'''Shadow detail''' - details visible in areas that are darkest in the subject. *'''Shadows''' - darkest areas in a photographic print. *'''Shellac''' - natural resin with a low melting point. It is mainly used on dry mounting tissue. *'''Shelf life''' - length of time unused material or chemicals will remain fresh. *'''Shutter''' - mechanical system used to control the time that light is allowed to act on the sensitive emulsion. *'''Shutter speed''' - action of the shutter that controls the duration of an exposure. The faster the speed the shorter the exposure. Shutter speed settings are given in the fraction of a second. Each setting is half the duration of the preceding one in a constant scale, marked on the shutter speed dial or ring. *'''Side lighting''' - light striking the subject from the side relative to the position of the camera. It produces shadows and highlights to create modeling on the subject. *'''Silhouette''' - photographic image in which the subject is seen as a solid black shape against a light background. *'''Silicon release paper''' - thin, heat resistant interleaving paper, used between a photographic print and textured material in a heated press. It allows remolding of the print surface yet prevents the two materials from sticking together. *'''Silk print''' - image made on silk by means of the diazo or dye printing methods. *'''Silkscreen''' - method of applying inks to paper or similar materials using a nylon stencil produced by photographic means. *'''Silver halides''' - light sensitive crystals used in photographic emulsions, i.e. silver bromide, silver chloride and silver iodide. The change from white to black metallic silver when exposed to light. *'''Silver nitrate''' - chemical combination of silver and nitric acid. It is used in intensifiers, physical developers and photographic emulsions manufacture. *'''Silver reclamation''' - system for recovering silver from exhausted solutions. *'''Silver recovery''' - system of reclaiming silver from exhausted solutions. *'''Silver salts''' - compounds of silver. *'''Simultaneous contrast''' - effect that adjacent color hues have upon each other. *'''Sizing''' - very dilute, gluey substance used to prepare surfaces for coating by filling in pores and giving even absorbance. *'''Sky filter''' - outdated term for a filter which has a graduated density across its surface. *'''Slit shutter''' - narrow vertical slit either just in front of the emulsion or at a similar distance in front of the lens. Film is wound through the camera at a constant speed giving one long image along the length of the film. *'''Slow sync''' - flash technique for using the flash at a slow shutter speed. Flash shooting in dim light or at night at a fast shutter speed often results in a flash-illuminated subject against a dark background. Using a slower shutter speed with the flash brings out the background details in the picture. *'''Snapshot''' - term once used to describe a photograph taken with the I (instantaneous) setting on cameras. The term originally came from rifle shooting, when little or no time is allowed for aiming. *'''Snoot''' - cone shaped shield used on spotlights to direct a cone of light over a small area. *'''Sodium bichromate''' - chemical used in intensifiers, toners and bleaches. *'''Sodium bisulfite''' - chemical used in fixing baths as an acidifying agent. *'''Sodium carbonate''' - alkaline accelerator used in many general purpose and print developers. *'''Sodium chloride''' - used in some bleaches and reducers. *'''Sodium hexametaphosphate''' - water softener. *'''Sodium hydrosulfite''' - used as a fogging agent in reversal processing. *'''Sodium hydroxide''' - highly active alkaline accelerator used in conjunction with hydroquinone to produce high contrast developers. *'''Sodium metabisulfite''' - used as an acidifying agent in acid fixing baths. *'''Sodium sulfide'''- chemical used in sulfide (sepia) toning. *'''Sodium sulfite''' - chemical commonly used as a preservative in many developing solutions. *'''Sodium thiocyanate''' - alternative to potassium thiocyanate and is used as a silver solvent in physical and ultra-fine grain formulae. *'''Sodium thiosulfate''' - chemical used in many fixing solutions. It converts unused halides to a soluble complex which can be removed by washing. *'''Soft developer''' - paper developer that can be used alone or in combination with other developers (two-bath development) to achieve more subtle contrast control. *'''Soft focus''' - definition of a diffused image. This can be achieved at the camera or enlarging stage. *'''Soft focus lens''' - lens, uncorrected for spherical aberrations, used to produce a soft focus effect. *'''Solarization''' - reversal or partial reversal of tones in a photographic image caused by vast amounts of over-exposure. It is often inaccurately used to describe the partial reversal effect caused by fogging photographic material with light, which is actually the Sabattier effect. *'''Solubility''' - in general terms is the ease with which a solid will mix homogeneously with water to provide a chemical solution. *'''Spacing bracket''' - device used to position the camera at the right distance from the subject for the lens focus setting in closeup work. *'''Spectral sensitivity''' - relative response of a photographic emulsion to each of the colors of the spectrum, including infrared and ultraviolet. *'''Spectrum''' - usually used in reference to the visible part of the electro-magnetic spectrum, i.e. the color bands produced by diffraction, and arranged according to wavelength, when white light is passed through a prism. *'''Speed''' - sensitivity of a photographic emulsion to light. Films are given ISO or DIN numbers denoting speed characteristics. *'''Spherical aberration''' - lens fault which causes loss of image definition at the image plane. Its affects are reduced by stopping down. *'''Spool''' - bobbin like object consisting of a narrow core with flat disks on either end, around which the film is wound. *'''Spotlight''' - artificial light source using a fresnel lens, reflector, and simple focusing system to produce a strong beam of light of controllable width. *'''Spot meter''' - used to get accurate light readings of a small part of a subject. It uses a narrow angle of view to measure within limited areas. *'''Spotting''' - method of retouching. Blemishes or unwanted details are removed from negatives and prints by brush and dye or pencil. *'''Sprocket holes''' - perforations on both edges of 35mm film, which engage with the teeth of the film transport mechanism. *'''Squeegee''' - tool with rubber blades or rollers, used to squeeze water out of wet prints. *'''Stabilization''' - alternative method of fixing. Unused halides are converted to near stable compounds, insensitive to light. No washing is required. *'''Stabilizer''' - final solution often used in color processing which leaves the dyes produced by chemical development more stable and fade resistant. *'''Staining developer''' - developer, such as pyro, in which the oxidation products give extra image density by staining the gelatin. *'''Stand''' - alternative name for a tripod. *'''Static marks''' - jagged fog marks on negatives as a result of a very dry film being rewound or unwound too rapidly. *'''Step wedge''' - printed series of density increases, in regular steps from transparent to opaque. Its a method of making exposure tests when enlarging. Stereoscope - viewer which accepts pairs of stereoscopic images. *'''Stereoscopic camera''' - camera designed to take simultaneous images of the same subject from viewpoints separated by the same distance as that between the eyes. *'''Stereoscopy''' - method of creating a three dimensional effect on a two dimensional surface using a pair of images taken from slightly different viewpoints, and viewed through specially made stereo viewers. *'''Still life''' - inanimate subject, either in the studio, or outdoors, normally arranged to make full use of form, shape and lighting. *'''Stop''' - aperture of a camera or enlarging lens. *'''Stopping down''' - reducing the size of the lens aperture and thus the amount of light passing into the camera. It increases depth of field. *'''Stress marks''' - black lines on a photographic emulsion caused by friction or pressure. *'''Subbing''' - layer applied to a photographic support as a foundation for the emulsion. *'''Subject''' - person or thing photographed. *'''Subjective photography''' - interpretive image of the subject, with results influenced by the attitude of the photographer. *'''Successive color contrast''' - trick of the human eye by which the impression of a color is influenced by an immediately preceding color stimulus. *'''Sulfide toning''' - conversion of a black metallic silver image into a brown dye image. Usually known as sepia toning. *'''Sulfuric acid''' - high corrosive chemical used in reducers. *'''Supper coat''' - top coating of non-sensitized gelatin added to sensitized emulsions to form a protective layer. *'''Surface development''' - development process in which the image forms primarily on the surface of the emulsion and then penetrates deeper. *'''Surge marks''' - streaks on the image from each of the sprockets holes of 35mm film caused by excessive agitation. *'''Surrealism''' - originally an early 1920s artistic movement, now taken to indicate the production of unreal images which defy reason. *'''Swing back/front''' - term used to describe the movable lens and back panels of most view and monorail cameras. They allow manipulation of perspective and depth of field. *'''Symmetry''' - effect of an evenly balanced arrangement of visual information, such as pattern, on either side of a central division. ea920f4ca0f50707dc7483570b3e6470b45c84ef 0 487 1125 1124 2013-05-12T02:54:43Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:SSY1.jpg]] The SSY-1 laser is available surplus very inexpensively. It has a Plano-Plano resonator with [[Nd:YAG]] as the active medium and a passive Q-Switch. This laser can be modified to make a master oscillator but the alignment of a Plano-Plano cavity is the most sensitive of any cavity configuration making it very difficult to align and keep in alignment. This is taken care of very well in the original design but it makes for a difficult design to modify. ie. increase the cavity length. Replacing the OC (Output Coupler) with a resonant reflector helps with the coherence length but alignment is made simpler by replacing the HR (Highly Reflective Mirror) with one with a large radius. It's output is not polarized and has multiple spatial and longitudinal modes. Since the cost is so low many amateur hologaphers are working at modifying it for holographic use. '''Specs''' *Plano/Plano Resonator *Nd:YAG 4 mm x 50mm *Passive Q-Switch *Diffuse Cavity *Flash Lamp 3mm bore x 35 mm long *Recomended Flash Lamp input 900V at 15J *Output 15 to 50 mj at 1064nm *100us optimal flash lamp pulse [http://www.repairfaq.org/sam/laserscl.htm#sclsy1 Sam's Laser FAQ on the SSY-1] 6c9757e300f13ffe695f9ffe944c7c32f718bce7 0 488 1127 1126 2013-05-12T02:54:43Z Jsfisher 1 1 revision wikitext text/x-wiki ==Safe Electrical Procedures== From LBL. '''Positively ensure the correct circuit is identified before lockout and tagout:''' Almost every week, some electrician or technician is hurt in the United States because the breaker he/she locked out was the wrong one. This type of accident is so easily preventable, yet it is far too common. Before you lock out a circuit breaker or power disconnect switch, check that you are locking out the correct breaker — the one that controls the equipment on which you will be working. Breaker off, the equipment stops. Breaker on, the equipment runs. Then, and only then, lock it out! '''Whenever possible de-energize the equipment before testing.''' Conduct tests with the electrical equipment deenergized, or, if there is no other way to perform the test, with reduced hazard. '''The employee in charge must conduct a briefing before all energized electrical work:''' Before starting any diagnostics & test energized electrical work having a Hazard Class greater than 1A or 1B, the supervisor or his/her designee, must complete a Job Planning Checklist (Appendix C) and conduct a job briefing with the employee(s) performing the work. '''Identify hazards and anticipate problems:''' Think through what might go wrong and the consequences of that action. Do not hesitate to discuss any situation or question with your supervisor and coworkers. '''Resist “hurry-up” pressure:''' Program pressures should not cause you to bypass thoughtful consideration and planned procedures. '''Don’t hesitate to use the Stop Work Policy:''' LBNL has a stop work policy (PUB-3000, Chapter 1.5) Do not hesitate to use it if you see a fellow worker performing unsafe acts. '''Always consider electrical equipment energized unless positively proven otherwise:''' When working on electrical equipment, treat the equipment as live until it is tested, locked, tagged, shorted, and/or grounded, as appropriate. '''Use suitably rated electrical devices only as intended:''' Electrical devices shall be fully rated for the system to be tested, and must not be modified beyond the intent of their design. '''Remove or cover all jewelry before performing energized electrical work:''' This includes rings, watches, or metal pendants and chains that could inadvertently fall into the work. Metal-framed glasses must be restrained when working around electrical equipment. '''Know how to shut down equipment in an emergency:''' Know the location, and operation of, emergency disconnects for all sources of power to equipment before beginning energized work. '''Know LBNL emergency procedures:''' All persons working in areas of high hazard (with high-voltage power supplies, capacitor banks, etc.) must be trained in emergency response procedures, which should include cardiopulmonary resuscitation (CPR) certification. '''Design for safety:''' Consider safety to be an integral part of the design process. Protective devices, warning signs, and administrative procedures are supplements to good design—not a substitute for it. Engineering controls are always preferable to administrative controls. Completed designs should include provisions for safe maintenance. '''Reset circuit breakers only after the trip problem has been corrected:''' When a circuit breaker or other over current device trips, it is usually due to an overload or fault condition on the line. Repeated attempts to re-energize the breaker under these conditions may cause the breaker to explode. Do not attempt to reset a circuit breaker unless the problem has first been identified and corrected or isolated. ''Maintain the protection of covers, barriers and shielding:''' When you remove a panel or cover for access (a barrier), replace it with a temporary barrier to restore at least some of your protection. This could be a transparent Lexan sheet, a rubber sheet or blanket, etc., place over the portions of the equipment under test to which you do not need access. '''Never drill into a wall or floor slab without Facilities' approval.''' See Admin 053 Facilities Penetration Policy. When drilling into a wall or floor, wear suitable PPE for the working conditions (dirt, slurry, debris) in case of an unknown electrical hazard. At a minimum, this will include safety glasses, hard hats, all leather shoes, and fully rated gloves. '''Never modify or penetrate premises wiring conduit or enclosed wireways:''' Only qualified and authorized Facilities Department personnel are allowed to work on premises wiring, conduits or enclosed wiring. 1fd10a08506bee1906c5c7ee1fb5d42a471f893d 0 489 1129 1128 2013-05-12T02:54:44Z Jsfisher 1 1 revision wikitext text/x-wiki blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> 1dcf5788845dad70cef5d1463b6383542e065f7c 0 490 1131 1130 2013-05-12T02:54:44Z Jsfisher 1 1 revision wikitext text/x-wiki ==Scratch-O-Grams or Hand Drawn Holograms== [[Image:Face2.gif]] Scratch-O-Gram by Raul. Scratch-O-Grams or Hand Drawn Holograms were first popularized by William J. Beaty in 1995. His article titled [[http://www.amasci.com/amateur/holo1.html Abrasion Holography]] is available on Science Hobbiest's website. A more technical paper by William J. Beaty was published by SPIE titled [[http://amasci.com/amateur/hand1.html Drawing Holograms by Hand]]. Tips for fabricating Scratch-O-Grams are [[http://amasci.com/amateur/holohint.html here.]] The definitive reference is: W. T. Plummer and L. R. Gardner, "A mechanically generated hologram", Applied Optics Vol.31, No. 31 (1 November 1992) pp.6585-6588. ==Computer Help for Designing Hand Drawn Holograms== Recently Holography Forum Member Raul provided a simple Visual Basic program for generating the scratch patterns from a 3D file. It currently works with small .3ds files or with .mcl files. .mcl files are created by a free program called MarbleCLAY and is available [http://homepage3.nifty.com/escargot/DownLoadFrm.html here]. Raul's program is called [http://www.holographyforum.org/files/3dS.zip 3dSilhouette]. The VB6 libraries are available [http://www.microsoft.com/downloads/details.aspx?familyid=7b9ba261-7a9c-43e7-9117-f673077ffb3c&displaylang=en Here]. He has a web site [http://3dalter.50megs.com/ here]. It generates a pattern showing the length and placement of the compass for making the scratches for complex objects. It can also break the object into pages of equal length lines to speed fabrication. ==Here are the instructions from Raul:== ''This is the program for making patterns. It is written in Visual Basic 6, and it needs some libraries. You need to download them or simply install VB6 on your PC. It works with .mcl, or.3ds input files. Mcl are marbleclay 3d files. Marbleclay can be freely downloaded from Internet, and is a very easy 3D editor.'' ''You need to create a folder c:\3dSilhouette and extract files into that folder.'' '''The software will not run at any other path.''' ''Patterns are printed in letter format sheets, files are located in the OUT folder. Several files may be generated, depending on object complexity.'' ''3d object can be rotated, moved and scaled. There is an option GetSilhouette that generates a wire frame model leaving only most important lines of the object for minimizing its complexity. You can then edit the object adding or erasing lines by simply double clicking on them.'' ''Set render options:'' ''XYScale –Vertical and Horizontal size of the object,'' ''Min Radius, Max Radius –They define object depth'' ''Left and Top margins – Is obvious.'' ''Line and scratch spacing define hologram density. Try to set a bigger number to reduce the number of patterns.'' ''Then you go to generate patterns, and render.'' ''With Line Patterns, scratches are drawn putting the compass centre on the bottom end of the lines and use line length as compass aperture. For horizontal lines, center compass in the right end. I use to make arc-shaped scratches with convexity looking to the top side of the sheet.'' '''One tip:''' ''If yow visualize the hologram in the way it appeared on the screen, image will go on deep. If you turn it upside down, image will pop in front of the sheet.'' '''Other tip (For Line Patterns)''' ''No matter that in even pages patterns appear horizontally all scratches are drawn the same way. In that cases you must center the compass in the right end of lines, and draw scratches in such a way that the tops of the arches aim to the top of the sheet. For vertical lines, it is more intuitive: center at the bottom and the top of arches matches with the top end with the lines.'' ''Equal depth pages option was implemented lately following a suggestion of Adam Libura.'' ''Program displays a page for each depth value (compass aperture) calculated. It is intended mostly for drawing on a transparency sheet laying directly on the lcd display screen. It displays a page of starting points for each compass aperture, which is shown in the left bottom corner of the page. You can use patterns right from Patterns window, or display bmp image files using windows image viewer. Pressing the button “Follow”, a cross pointer will navigate over the points to make it easier to find them correctly.'' '''One Suggestion:''' ''For drawing scratches in a transparency sheet, you can put the transparency on the sheet with pattern. Put compass tip on a piece of thick transparent plastic, to avoid damage the transparency. You can freely move the plastic piece on the transparency surface, to match the compass center with the bottom end of the lines. When lines are horizontal, center should be positioned at the right end of the lines.'' '''Another Suggestion:''' ''When viewing hologram, I backed it with a mirror, it help to increase brightness. I used to hang the hologram on the wall, at the height of the eyes, and illuminate it with a bright focus from a 3m distance. For viewing, I stayed 3m from the hologram, and focus hanged 20 cm over my head, in such a way that the focus slightly disappeared over the top border of the mirror.'' [http://www.youtube.com/watch?v=A40e2PgHPCQ U-tube Demonstration of a Scratch-O-Gram made by Raul] b9c568ea5d97299fca4d1280e0e3269a15f85f8a 0 491 1133 1132 2013-05-12T02:54:45Z Jsfisher 1 1 revision wikitext text/x-wiki DCG holograms are very sensitive to re-adsorbing moisture. If a hologram disappears after bieng in humidity you can usually get the image back by reprossing the hologram in alcohol drying baths. If you want to make sure the hologram is permanent you will need to seal the back side. The two most common methods are to seal the back with a glass plate or to coat the back with a cyanoacrilate adhesive. Most art holographers use the glass plate method. == Glass Plate Method 1 - Full Coverage (UV Epoxy) == When sealing a hologram with the glass plate method it is important to scrape at least 3mm of gelatine off the edge all the way around the hologram. This insures that the edge of the gelatin is sealed. Once this is done the epoxy is spread evenly over the entire emulsion and a glass plate is place over the sealant. The entire sandwich is place over or under a UV light (black light) to cure. This sealant is bought to have the same index of refraction of glass and should dry clear. This sealant can be expensive. If you wish to make your own UV sealant see Jeff Blyths "Do It Yourself" UV sealant below. == Glass Plate Method 2 - O-Ring (Standard Epoxy) == An ecconomical approach that works very well is to use 5 minute two part epoxy (at any hardware store). Scrape 3mm of gelatin off the edge all the way around as indicated above as best as you can. Clean the glass cover plate. Mix the two parts of the two part epoxy as directed on the epoxy label. I use a q-tip cut in half and a piece of scrap glass. Once the epoxy is mixed use a tool, like the q-tip rod to evenly spread a bead of epoxy around the scraped 3mm area on the hologram. Place the cover plate on and insure there are no place missing any epoxy by visually inspecting it. Place on level surface and let dry. '''Here is a post from Jeff Blythe on making UV cure epoxy at home:''' ===A DIY UV sealant=== In keeping with the grand DIY philosophy of the Forum I thought I would put down some basic ingredients for making your own out of materials which are fundamentally cheap because of their big industrial use. However before that a hypothesis that fits observations I have made. I believe that the reason DCG has been so notoriously difficult to seal up and prevent moisture getting in is not necessarily due to any fault of hydrophobic glues being somehow rather more moisture pervious than expected. I believe the real trouble has been that sandwiched between 2 glass sheets the gelatin layer contracts with age and builds up a significant vacuum. This results eventually in outside air getting through microcracks inspite of diligently thick glue having been applied around the edges of the sandwich.. This contraction effect might be just to do with the basic properties of the gelatin under prolonged lighting but it could well be more to do with the final stubborn traces of water /alcohol still hanging about and alcohol vapour can very gradually (we can be talking “years” here) make its way through the edge sealant increasing the vacuum effect. Anyway whatever the cause an obvious way to minimise it is to put the newly processed DCG in a really dry warmer I am not sure what temperature is best but 60-70C for as long 24 hours seems to work or alternatively I have left them in a really effective desiccator for a week. Then without giving the ultra dry DCG a chance to re-absorb ambient humidity a dry glass cover plate with dry sealant can be put on. This topic has been discussed on the forum before and some of you guys have had vastly more experience than me at sealing. To make a UV curable sealant,you need a monomer, crosslinker, and free radical generator for UV. Monomer : Methyl methacrylate or better (more hydrophobic) is butyl methacrylate (NB. Not tert-butyl methacrylate) Crosslinker: Ethylene dimethacrylate (alternative silly name by Sigma Aldrich is ethylene glycol dimethacrylate). UV sensitizer (free radical generator in UV.): DMPA or dimethoxyphenyl acetophenone. One can use about 1 part DMPA to 100 parts monomer to 5-10 parts crosslinker. It gets harder the more crosslinker you add of course. (~80-100% crosslinker just cracks up). But the mix has initially a rather low viscosity , lower than the commercial stuff. It is a good idea to store mixture over silica gel in a fridge in the dark. Jeff 04551d1a55302ad8c0ac37991d9f6fb8e031cd24 0 492 1135 1134 2013-05-12T02:54:45Z Jsfisher 1 1 revision wikitext text/x-wiki SEEING THE LIGHT Optics in Nature, Photography, Color, Vision and Holography David Falk, Dieter Brill, David Stork, John Wiley & Sons, New York, 1986, ISBN 0-471-60385-6. One of the classic contemporary texts on optics, although it was written before the digital age hit. But the explanations of the classic optical phenomena are right on, with a wacky sense of humor appearing from time to time. Sprinkled throughout the text are TRY ITS which are demonstrations that can be done at home, like making a periscope, a pinhole and an anamorphic slit camera based on 126 film cartridges (no longer manufactured by Kodak since 1999, but still hanging in there thanks to Ferrania of Italy!), conical anamorphic photographs, and many more. There are also PONDERS which really get you thinking about what you just read or experienced. The frontispiece is the first Random-Dot Stereogram (aka Magic Eyes) that I ever saw and they describe how to make one without using a computer! Their holography section is surprisingly quite comprehensive. One of the authors, David Falk, has published an article in Scientific American and devotes a whole web site to nay-saying the basic premise of David Hockney’s book, Secret Knowledge. I myself prefer to believe in Hockney’s explanation of the use of optical devices to render perspective and the fact that the artists kept their tricks secret, knowing what I know about 19th century photographers and 20th century holographers. The only downside of this book is that some of the photographs could have been reproduced better. But there are a lot of them! A must get book for all practitioners of optical arts! It is a bit on the pricey side, but what textbook isn’t in this day and age! -Ed Wesly b8e0f6544623c88c4826d1f502a171dfa4149fae 0 493 1137 1136 2013-05-12T02:54:45Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:SVorobyov.jpg]] A physicist, expert in holography, Ph. D. of technical sciences. Sergey Vorobyov has been studying holography since second year of the university. During 30 years of his work, he took part in the development of the main directions of applied holography - hologram manufacturing on silver-halide photomaterials, hologram production on dichromate gelatin, manufacturing of holograms for information systems, embossed and color holography and etc. Sergey Vorobyov was a member of the commission on industrial application of photoplates for holography: PFG-01, PFG-02, PFG-03, PFG-04 at the Slavich company. He took part in testing those plates and optimization of the manufacturing process. Sergey Vorobyov is director of holographic studio at the All-Russian Exhibition Center (Moscow). He developed unique technology of recording and copying of pulse holograms. Commercial manufacturing of display holograms has been organized with his help. Sergey constantly improves technology of manufacturing of transmission and reflection holograms. As a holography popularizer he wrote the course "25 holography lessons". It has been published in Russian and English on [http://www.holography.ru www.holography.ru] web site. Sergey Vorobyov also developed the compact kit for amateur holography. f198df26477f86b0c9892de50a49c1b2ea8cecbb 0 494 1139 1138 2013-05-12T02:54:46Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:SZharkiy.jpg]] Sergey Zharkiy graduated from the Moscow State University, Faculty of Physics with a MS (Master of Science) in Physics in 1999. He studied lasers and holography at the International Laser Center of Moscow State University. He took part in scientific conferences with his articles on holography and laser applications. Sergey Zharkiy is an author and developer of [http://www.holography.ru Holography.Ru] web site. He wrote and translated many articles for this web site. Sergey also designed and made several art holograms for gallery of Russian Holographic Studios. Sergey Zharkiy took part in development of compact holographic kit for amateur holographers. He is also author and director of educational film (DVD) on holography. 38787c57278d1cf03021f1544097ac7ecf9e658e 0 495 1141 1140 2013-05-12T02:54:46Z Jsfisher 1 1 revision wikitext text/x-wiki ===[[Single Beam Reflection]]=== [[Single Beam Reflection|Click here]] for illustrations and explanations. No plateholder or card blockers. Just the basics. ===[[Single Beam Transmission]]=== [[Single Beam Transmission|Click here]] for illustrations and explanations. No plateholder or card blockers. Just the basics. ===Split beam reflection=== ===Split beam transmission=== [[Path Length Matching]] [[Tips for Pulsed Ruby Holograms]] ===[[H1 to H2]]=== The [[H1 to H2]] copy technique is commonly used for production and copying of commercial art holograms. Though the setup is more complex and difficult than a simple single beam arrangement, the result can be MUCH brighter than the original H1 because during the copying process one has complete control over the [[Beam Ratio]]. Commercially, the savings in time when making many copies from a master H1 make it indispensible. Here is a discussion on using [[Brewster's Discussion|Brewster's angle]] in [[H1 to H2]] setups. One fact, that if not taught, will be learned very quickly, is very evident in the final hologram and can waste a lot of time, energy and materials. That is, it is the pseudoscopic real image that is being made from the H1 onto the H2. Because this image is pseudoscopic an overhead reference beam used in creating the H2 will create a hologram that if displayed also with an ovehead display light will display a pseudoscopic image. I doubt this is what is desired. Thus it is important that in the copy set up the reference beam needs to enter the plate from the bottom and what is actually the back of the hologram if the display lighting is needs to come in from the top front. I tried to illustrate this in the image below and this is for a reflection H2 copy. [[Image:H2Geometry.JPG]] ===Rainbow holograms=== A Rainbow hologram is a white light viewable transmission hologram. The vertical parallax is sacrificed so that the hologram can be viewed in white light. Most Rainbow holograms are displayed with a silver backing so that even though they are transmission holograms, they can be viewed as a reflection hologram, that is, with the light behind you and over your shoulder. A rainbow hologram (H2 transmission) can be made from any transmission H1 hologram. The key is to restrict the image from the H1 down to a slit. There are a variety of ways to do this (briefly describe below in the “Embossed Holography” section) but the simplest, and one we will explain here, is to set your table geometry up as a standard transmission H1 to transmission H2. Then simply mask the full size H1 down to a slit approximately 1cm in width along the horizontal relative to the object. If you have a white card in where the H2 should be you will see as you mask down the H1 the image’s depths on the white card become more visible or more in focus. Then expose as needed. Then when viewed with white light as a transmission the hologram will have full horizontal parallax when you move you head side to side but as you move your head up and down the image will scroll through the colors of the rainbow, thus the name. If you take your credit card outside and look at it in the sunlight, you can easily observe these phenomena. ===Saxby bypass=== ===Multiple coherence volumes=== Click here [[Multiple Coherence Volumes]] ===Path Length Matching=== Click here [[Path Length Matching]] ===Stereograms=== Stereograms are also called Muliplexed holograms. The idea behind the proceedure is very straight forward but depending on the number of slits, the actual technique can very difficult or to say the least, time consuming to produce. The basic building block of this hologram is the master H1 hologram. The master hologram is made up of individual holographic slits, which usually are simple 2D objects. But like the frames of a movie, each slit has a slightly different perspective. If you want to really invision this, take a completed tranmission hologram of an object and cut the film into very narrow slits, about 3mm in width. Now illuminate each slit and project the image onto a white screen. Because of the narrowness of the slit you will notice in the illumination of one slit that the real image, when projected on a screen, has most of it's depth focused on the screen at one plane. This is similar to the slit technique in the Embossed Holography section below. To make the individual slits, simply set your geometry up to make a tranmisson hologram. Usually the object used is a tranmission LCD screen in which the "object" can be rotated via a computer for the subsiquent frames or slits. A diffusing screen is also placed against the LCD screen on the opposited side of the LCD screen with respect to the holographic plate. The idea is to diffuse the laser light before it goes through the LCD screen and finally on to the plate. This technique can also be applied to transparancies or negative photographic or movie film instead of and LCD screen. When the LCD screen has the first of a series of consecutive images on it, the holographic plate is masked at one end down to a few millimeters slit. The exposure is then made. Now the next image is advanced on the LCD screen and the slit mask is moved to the adjacent spot on the holographic plate and the second exposure is made. This is repeated for every "frame". After development in essence what you have is a holographic plate that has many slits side by side on it with the slits containing subsiquent views of an object or scene all from a slightly different but adjacent perspective. When this master is copied onto another holographic plate (H1 to H2 copy set up) all perpectives form at the same relative location in space at the H2 plate. Then when this plate is processed and viewed a 3d image can be seen because one eye sees one perspective and the other eye sees another perspective allowing the brain to create a 3d image of the object. This is truely a great technique for scaling down holograms of people or places to smaller sizes which can fit on 4x5 plates. Because the hologram is made from 2d images is is also possible to holograph what normally could not be holographed, as is something that cannot be brought into the lab. Frank DeFreitas has great and easy step by step intstructions to get you started in Stereogram Portraits on his web site. http://www.holoworld.com/holoportraits/index.html ===Embossed Holography=== [[Embossed Holograms]] f29afe09db7ccf33de0abfe0fb05c511b2d53e61 0 496 1143 1142 2013-05-12T02:54:46Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.mccormackholography.com/ Sharon's Website] Sharon McCormack was born in New York City and now lives and works in the Columbia River Gorge National Scenic Area, White Salmon, Washington. Since 1975, Sharon's professional activities have included Owner/ Director, School of Holography, San Francisco, CA to holographic lens system construction for X-ray applications to lecturing, consulting, and commissioned work in the field of holography. Over that period, Sharon has created numerous world-wide group & solo exhibitions, has won many prestigious awards & grants, and has been featured in a broad range of publications from technical journals to sport magazines. 40b8e36f158ef1844bb85c80f16a54396ebc55ec 0 497 1145 1144 2013-05-12T02:54:47Z Jsfisher 1 1 revision wikitext text/x-wiki Here is a list of tips for using basic sho tools to work in holography. It is not comprehensive but it should be enough to get you started with a new tool. *[[Glass Cutter]]- For scoring and breaking glass sheet. *[[Glass Grinder]]- For shaping and smothing glass edges. *[[File]] - For removing small amounts of material. *[[Rasp]] - For removing material more quickly than a file. *[[Knife]] - For marking, cutting and shaving. *[[Scraper]] - For finishing and leveling *[[Square]] - To layout lines and general set up. *[[Straight Edge]] - To layout lines and for set up. *[[Hack Saw]] - To cut metal. *[[Hand Tap]] - To thread holes. *[[Hand Die]] - To thread rods. *[[Drill Bits]] - To drill Holes. *[[Reamers]] - To make accurately sized and very round holes. *[[Drill Press]] - To make precise holes. *[[Dremel Tool]] - High speed rotary tool. *[[Router]] - For making slots and forming edges. *[[Table Saw]] - To cut large material into smaller pieces. Can also groove. *[[Jig Saw]] - To cut shapes from thin materials. *[[Skill Saw]] - A hand held version of a table saw. *[[Band Saw]] - To make resaw larger stock or make curved cuts. *[[Jointer]] - To clean an edge from a band saw or table saw. *[[Mill]] - To cut precice edges or slots. *[[Lathe]] - To cut precise round shapes. *[[Belt Sander]] - To shape small parts or finish surfaces. *[[Bench Grinder]] - To shape metal parts by hand. *[[Concrete Basics]] - Many tools can be made from concrete. *[[Power Tool Safety]] - Don't hurt yourself we like you! *[[Thermometer]] *[[Epoxy]] c625293bb960fa7f055922265481fed14639fbe3 0 498 1147 1146 2013-05-12T02:54:47Z Jsfisher 1 1 revision wikitext text/x-wiki For recording holograms, some form of shutter is always necessary: switching on and off the laser instead is not feasible, as a laser will always take some time until it comes into thermal equilibrium, and before that there will be a lot of frequency drifts and [[Mode Hop]]s that will ruin the hologram. The settling time of a laser can be minutes up to one hour or so. The simplest method is to manually remove a black cardboard out of the beam path, but there is a great danger of induced vibrations on the holography table. This source of potential failure of a hologram is one of the easiest to exclude, by using an electronic shutter. Such a shutter can be used remotely controlled, or even fully automated if allows a programmable exposure time going off after some delay. This allows the holographer to be outside of the room during the shot, which is an important factor for cutting down disturbing vibrations and air currents. Using an electronically timed shutter is also convenient for achieving reproducible exposure times. There are mainly two ingredients: first, the actual shutter and then, the controller. The actual shutter is in most cases a mechanical device. If it is to be present on the same table as the holography setup, it is important to avoid any kind of vibrations. One method to build such a thing is to glue a small piece of mirror or aluminum foil to the needle of a mechanical voltmeter, and to drill a hole through the scale of the voltmeter to provide a path for the beam. The advantage is that the motion is very gentle and hardly induces any vibration. For higher power lasers, somewhat more massive shutters are better suitable, and these need to be mechanically isolated from the holography setup (eg by putting them on an extra table together with the laser). Often Ilex (now Melles Griot) electronic shutters are available as surplus for photographers. Another method to build fast-acting shutters from broken hard disks is described [http://optics.ph.unimelb.edu.au/atomopt/publications/shutter_rsi75_p3077_2004.pdf here]. Many shutter controllers made for photographic dark room use are suitable and are easily available on ebay. Just make sure that the programmable exposure time lies in the range that is useful for holography (ie, one second to one or several minutes depending on your setup). Having the possibility of an extra delay of 10 minutes or so before shooting allows a fully automated setup without direct user intervention. All this can conveniently be achieved also by a simple computer interface. 529c9b2be66ed9a6315ec4e7c7d59fc791360182 0 500 1151 1150 2013-05-12T02:54:47Z Jsfisher 1 1 revision wikitext text/x-wiki {| align=center border=1 | Material | Thickness (um) | Sensitivity uj/cm2) Sectral Sensitivity (nm) | 442nm | 514nm | 633nm | 694nm | Resolving Power lp(mm)-1 |Grain Size (nm) |- | '''Slavich''' |- | PFG-01 | 7 | <700 | | | 80 | | >3000 | 35-40 |- | PFG-03M | 7 | <700 | | | 1500 | | >5000 | 10-20 |- | VRP-M | 7 | <550 | | 80 | | | >3000 | 35-40 |- | PFG-03C | 9 | 400-700 | 1000 | 2000 | 1000 | | >5000 | 10-20 |- | '''Colourholographic''' |- | BB-700 | 7 | <700 | | | 50 | 150 | >2500 | 50-60 |- | BB-640 | 7 | <650 | | | 150 | | >4000 | 20-25 |- | BB-520 | 7 | <540 | 150 | 150 | | | >4000 | 20-25 |- | BB-450 | 7 | <470 | 150 | | | | >4000 | 20-25 |- | '''Kodak''' |- | 131PX | 9 | <650 | 2 | | .5 | | >1250 | 70 |- | 131CX | 9 | <650 | 2 | | .5 | | >1250 | 70 |- | 120PX | 6 | <750 | 60 | | 40 | 40 | >1250 | 70 |- | 120CX | 6 | <750 | 60 | | 40 | 40 | >1250 | 70 |- | '''FilmoTec-ORWO''' |- |GF40 (gelantin film) |6 | UV to blue-green after sensitisation | | | | |not relevant | |- | HF53 | 6 | <550 | |1000 at 535nm | | | >5000 | |- | HF55 | 6 | <550 | |250 at 535nm | | | >3000 | |- |HF65 |6 |580 to 660 | | |<100 | |>3000 | |- | '''Ultimate''' |- | Ultimate 15 | 7 | <700 | | 150 | 150 | 150 | >5000 | 15 |- | Ultimate 08 | 7 | <650 | 120 | 200 | 200 | | >7000 | 8 |- | '''Fuji''' |- | HL-30 | | 100-200 | | | | |3000 |30-40 |- |} b455b4b9391b1cd1d893ba01c227d577056983f4 0 501 1153 1152 2013-05-12T02:54:48Z Jsfisher 1 1 revision wikitext text/x-wiki Silver Halide is one of the most popular recording materials. The historical and available commercially available films properties are listed here: *[[Silver Halide Film]] *[[DIY Silver Halide Film]] *[[Silver Halide Processing Chemistry]] *[[Silver Halide Film vs Chemistry vs Hologram Type]] *[[Silver Halide Sensitized Gelatin]] SHSG *[[Index Matching]] *[[Pre-Swelling]] *[[Post-Swelling]] *[[Squeegee Technique]] *[[Fringe Photos]] *[[Painting Holograms]] *[[Exposure Tests]] *[[Hardening Holograms to Fix the Color]] *[[Psuedocolor Processing]] *[[Laminating Film to Glass]] 3454f949841c27174a442f2f07ec80d99d76760f 0 502 1155 1154 2013-05-12T02:54:48Z Jsfisher 1 1 revision wikitext text/x-wiki {| align=center border=1 | Material | Thickness (um) | Sensitivity uj/cm2) Sectral Sensitivity (nm) | 442nm | 514nm | 633nm | 694nm | Resolving Power lp(mm)-1 |Grain Size (nm) |- | '''Slavich''' |- | PFG-01 | 7 | <700 | | | 80 | | >3000 | 35-40 |- | PFG-03M | 7 | <700 | | | 1500 | | >5000 | 10-20 |- | VRP-M | 7 | <550 | | 80 | | | >3000 | 35-40 |- | PFG-03C | 9 | 400-700 | 1000 | 2000 | 1000 | | >5000 | 10-20 |- | '''Colourholographic''' |- | BB-700 | 7 | <700 | | | 50 | 150 | >2500 | 50-60 |- | BB-640 | 7 | <650 | | | 150 | | >4000 | 20-25 |- | BB-520 | 7 | <540 | 150 | 150 | | | >4000 | 20-25 |- | BB-450 | 7 | <470 | 150 | | | | >4000 | 20-25 |- | '''Kodak''' |- | 131PX | 9 | <650 | 2 | | .5 | | >1250 | 70 |- | 131CX | 9 | <650 | 2 | | .5 | | >1250 | 70 |- | 120PX | 6 | <750 | 60 | | 40 | 40 | >1250 | 70 |- | 120CX | 6 | <750 | 60 | | 40 | 40 | >1250 | 70 |- | '''FilmoTec-ORWO''' |- |GF40 (gelantin film) |6 | UV to blue-green after sensitisation | | | | |not relevant | |- | HF53 | 6 | <550 | |1000 at 535nm | | | >5000 | |- | HF55 | 6 | <550 | |250 at 535nm | | | >3000 | |- |HF65 |6 |580 to 660 | | |<100 | |>3000 | |- | '''Ultimate''' |- | Ultimate 15 | 7 | <700 | | 150 | 150 | 150 | >5000 | 15 |- | Ultimate 08 | 7 | <650 | 120 | 200 | 200 | | >7000 | 8 |- | '''Fuji''' |- | HL-30 | | 100-200 | | | | |3000 |30-40 |- |} b455b4b9391b1cd1d893ba01c227d577056983f4 0 503 1157 1156 2013-05-12T02:54:48Z Jsfisher 1 1 revision wikitext text/x-wiki Described here are sucessful chemistries to use for each qualifying film for a particular type of hologram. For specific formulations look at [[Silver Processing Formulas]]. ===Single Beam Transmission - Film vs Chem=== ====PFG-01==== For low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up. (Ed Wesly) ===Single Beam Reflection - Film vs Chem=== ====PFG-01==== (Ed Wesly)- Replay in the same wavelength use CWC2 developer with PBQ rehalogenating bleach (Ed Wesly)- Replay is color shifted use Pyro or CWC2 developer with Dichromate reversal bleach Replay in same color use JD3 - Integraf Replay shorter use JD2 - Integraf ====PFG-03==== (Ed Wesly)- Replay is same wavelength use Slavich Hardener with G2 Developer and Slavich Fixer ====BB640==== (Ed Wesly)- Replay in the same wavelength use Pyrogallol based developer with Rehalogenating bleach ===H1 Transmission - Film vs Chem=== ====PFG-01==== (Ed Wesly) - Replay in the same wavelength use CWC2 developer PBQ rehalogenating bleach Another case is for low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up (Ed Wesly). ===H2 Transmission - Film vs Chem=== ====PFG-01==== Another case is for low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up (Ed Wesly). ===H2 Reflection - Film vs Chem=== ====PFG-01==== (Ed Wesly) - Replay in the same wavelength use CWC2 developer PBQ rehalogenating bleach (Ed Wesly) - Replay is color shifted Pyro or CWC2 developer Dichromate reversal bleach ====PFG-03==== (Ed Wesly)- Replay is same wavelength use Slavich Hardener with G2 Developer and Slavich Fixer ====BB640==== (Ed Wesly)- Replay in the same wavelength use Pyrogallol based developer with Rehalogenating bleach b5cb77df2fb9ff0be3715c637250420362a0d19c 0 504 1159 1158 2013-05-12T02:54:48Z Jsfisher 1 1 revision wikitext text/x-wiki [[Silver Processing Formulas]] 2765fe4f109324532f33db373fa351134154da84 0 505 1161 1160 2013-05-12T02:54:49Z Jsfisher 1 1 revision wikitext text/x-wiki A hologram is basically a black and white image of the fringe structure at the film plane. Any black and white chemistry will work but because of the fine spatial frequencies involved special chemistries and films have been developed that make better holograms. The spatial frequencies of a hologram can be in the range of 300 to 6000 lines per millimeter. *[[Physical Development]] *[[Colloidal Development]] *[[Rehalogenating Bleach]] by Jeff Blyth *[[Reversal Bleach]] by Jeff Blyth *[[Fixer]] *[[Stop]] *[[Rinsing]] [[Silver Processing Formulas]] [[Defogging PFG-03]] 45998896c6948fdcfc2f88d3d5f14c97fb5d1f92 0 506 1163 1162 2013-05-12T02:54:49Z Jsfisher 1 1 revision wikitext text/x-wiki =SHSG for PFG-03C and PFG-03M= from: *'''Transmission and Reflection SHSG Holograms''' - Kim, Choi, Choi, Kim, Kim, Bjelkhagen, Phillips - SPIE *'''SHSG processing for three-wavelength HOEs recording in Silver Halide Materials''' - Kim, Choi, Bjelkhagen, Philips - SPIE I have made some assumptions about their process. Please read the source if you are serious about this process. ==Hardening bath== *Formaldehyde (37%) 10ml *Potassium Bromide 2g *Sodium Carbonate (anhydrous) 5g *Deionized Water 1L ==Stop Bath== *2% Acetic Acid Bath ==Bleach== (pH 5) *Cupric Bromide 1g *Potassium Persulfate 10g *Citric Acid 50g *Potassium Bromide 20g *Borax 30g *Chromium (III) Potassium Sulfate 20g *Deionized Water 1L Add 1g Metol after everything is mixed ==Fix Bath== *Ammonium Thiosulfate (anhydrous) 10g *Sodium Sulfate (anhydrous) 20g *Deionized water 1L ==Process== *Prehardening 6 min *Develop G282C Diluted 1 to 3 to 1 to 5 3 min *Rinse Running Deionized Water at least 3 Min *Stop *Wash? *Bleach (diluted 1:3) 15 min *Warm water bath (60C) 10 min *Wash? *Dehydrate 50% IMS 3 min *100% IMS 3 min *Dry in 45C oven 5 min *Vapor harden with Formaldehyde 25 min or 50% glutaraldehyde vapor *25min *Fix 2 Min *Wash *Dehydrate 50% Isopropyl 10 min *100% 10 min *100% 70C 2min *Dry in 45C oven. Seal with Pascofix ==Notes== From Martin: The two developers mentioned in US 4108661 might be candidates for developers a la G284c: I *hydroquinone: 16.5 g *potassium bromide: 1.7 g *sodium salt of EDTA: 1.7 g *potassium metabisulphite: 40 g *1-phenyl-5-mercaptotetrazole: 35 g *sodium hydroxide and water to make: 1 liter at pH 11.8. II *hydroquinone: 25 g *potassium bromide: 2.5 g *sodium salt of EDTA: 2.5 g *potassium metabisulphite: 62.5 g *1-phenyl-5-mercaptotetrazole: 50 mg *potassium thiocyanate: 0.5 g *sodium hydroxide and water to make: 1 liter at pH 11.8 (Colin's Note: These developers have some of the features but the MSDS includes Potassium Sulphite and Hydroquinone as the only listable toxins. Info from Kim et. al. G282C is the high speed reversal prosess for AGFA Millimask Plates. "Such non-tanning developers usually contain halide solvents and encourage sharp developed edges." -------------------------------------------------------------------------------- by Martin Maybe I should have pointed to another paper (also in SPIE 4659) by a Russian group (Evstigneeva, Drozdova, Mikhailov) dealing with SHSG. The authors recorded pulsed holograms on VRP plates (which incidentally are said to come close to PFG-01). (Colin's Note: VRP is green sensitive and PFG-01 is Red Sensitive. For more details see www.slavich.com) They describe the following processing steps: #Development in a non-tanning developer (SM-6); #rehalogenating bleach (permanganate); #intermediate alcohol (ethanol) drying; #uniform second exposure; #second development in diluted developer; #reversal bleaching (dichromate); #fixing; #dehydration in isopropanol. The potassium permanganate bleach is formed by: *Pot. permanganate ................0,4g *Sulfuric acid ...................0,4ml *Sodium chloride....................10g *Water...............................1L The second developer: *Sodium sulfite ......................5g *Metol................................5g *Hydroquinone........................10g *Ascoribic acid......................10g *Phenidon.............................1g *Sodium hydroxide....................10g *Water................................1L 1ea20453957e5ea0a2e7a0452069b48d03f7d741 0 507 1165 1164 2013-05-12T02:54:49Z Jsfisher 1 1 revision wikitext text/x-wiki This is a collection of chemistries for holographic development and holographic film manufacture. For the definitive source about holographic development please purchase a copy of SILVER HALIDE MATERIALS FOR HOLOGRAPHY AND THEIR PROCESSING by Hans Bjelkhagen ISBN 3-540-58619-9. Contact Integraf for JD-2, JD-3, JD-4, SILVER HALIDE MATERIALS AND THEIR PROCESSING by Hans Bjelkhagen or for Slavich Film. Many of these chemicals are very dangerous. Please don't breath the dust or fumes. Make sure to wear gloves and don't pour the used chemicals in your drain. Your drain goes to someone's drinking water! Don't forget to read and follow the MSDS. ---- Notes on Mixing Chemistry for Silver Halide Materials The order and methods you use for mixing is very important. Normally you add in the order of the formulation. Some of these formulations are likely to be out of order. ---- =TJ1= [[TJ1 Developer]] - By Jeff Blyth =JD-2= from Integraf for PFG-01 from Slavich Solution A *Distilled Water 100 Deg. F 750 ml *Catachol 20 grams *Ascorbic Acid 10 grams *Sodium Sulfite 10 grams *Urea 75 grams *Water 68 Deg. F 1 liter Solution B *Distilled Water 100 Deg. F 800 ml *Sodium Carbonate, Anhyd. 60 grams *Water 68 Deg. F to make 1 liter Mix equal parts A and B just before development. Mix enough for one hologram only. ( I have developed 3, But the first one is best) Bleach *Distilled Water 68 deg. F 750 ml *Potassium Dichromate 5 grams *Sodium Bisulfate 80 grams *Water 68 deg. F to make 1 liter Dissolve potassium dichromate completely before adding sodium bisulfate. The bleach can be used for a long time. At least 5 months shelf life. *Develop 2 minutes *Rinse 3 minutes *Bleach till clear (less than two minutes) *Rinse *Photo flo *Air dry =JD-3= from Integraf Developer Part A *Water 750ml *Catechol 20g *Ascorbic acid 10g *Sodium sulfite 10g *Urea 75g *Water to make 1L Part B *Water 750ml *Sodium carbonate 60g *Water to make 1L Bleach *Water 750ml *Copper sulfate 17g *Potassium bromide 55g *Succinic acid 2g *Water to make 1L Post Treatment *Water 300ml *Ascorbic acid 10g *Water to make 400ml Mix equal parta A and B. Working solution has a life of 8 hours. Only develop one hologram. Develop for 2 minutes with agitation. Soak in distilled water for 10 seconds. Wash for 3 minutes. Do not dilute bleach. Bleach emulsion side down till clear. Less than 2 minutes. Wash for 3 minutes. Dilute post treatment 1 to 10 with water. soak under bright light untill the hologram turns from pink to light brown. Wash for 3 minutes. =JD-4= from Integraf for PFG-03M from Slavich Developer Part A (1 liter)Quantity *Metol or Elon (p-Methylaminophenol sulfate) 4 g *Ascorbic acid (powder) 25 g Developer Part B (1 liter) *Sodium carbonate, anhydrous 70 g *Sodium hydroxide 15 g Bleach (1 liter) *Copper sulfate (pentahydrate) 35g *Potassium bromide 100g *Sodium hydrogen sulfate crystals 5g Mixing instructions Use three l liter (or larger)size clean glass or plastic bottles with leak proof caps. Label them A, B, and Bleach respectively. Warm the distilled or de-ionized water to about 40o C (warm to the touch). Fill the bottle marked A with 700 ml of warm water. Dissolve the Metol in it, then add the ascorbic acid. Add 300 ml of warm water to make 1 liter of Part A developer. Tightly cap the bottle. Part A will oxidized if it is exposed to oxygen. In time (over a few days to few weeks), the solution may turn yellow due to the oxidation of ascorbic acid; the solution is still useable. Once the solution turns dark brown, the potency is lost and should be disposed. One way of protecting it from oxidation is to subdivide the solution into smaller bottles so that the unused portions are in fully capped bottles, with little or no air space on top. Refrigeration also slows down oxidation (exercise extreme caution to prevent its mistaken identity as food). Follow the same procedure for Part B (add the sodium carbonate and sodium hydroxide in either order). This solution will keep for many weeks. Follow the same procedure for mixing the Bleach. This solution has very long shelf life. =Hardener - Slavich= Formalin 37% 10ml Potassium Bromide 2g Sodium Carbonate 5g Water to 1L =Fixer - Slavich= Methyl Phenidone 0.2g Hydroquinone 5g Sodium Sulphite(Anhyd.) 100g Potassium Hydroxide 5g Ammonium Thiocyanate 12g Water to 1L =Metol-Ascorbate developer= courtesy of Laser Reflections The formula is as follows: Metol-Acorbate Developer (Part A + Part B) Part A: *Metol 10g *Ascorbic Acid 80g *Water to 1000ml Part B: *Sodium Carbonate Anhydrous 120g *Sodium Hydroxide 14g *Potassium Bromide 4g *Water to 1000ml Use it in combination with a Fe-EDTA bleach - a safe, stable bleach which has a long shelf life. =Fe-EDTA Bleach= *EDTA (2Na) 30g *Fe(III) Sulfate 30g *Potassium Bromide 30g *Sodium Hydrogen Sulfate Crystals 30g *Water to 1000ml =Russian Emulsion Tips= From Jeffrey: When using Russian emulsions - Pre-develop gelatin hardening bath - Sensitizes and maintains colors, allows squeegee use *Distilled water 750 ml *Formaldehyde 37% (Formalin) 10 ml (10.2 g) *Potassium bromide 2 g *Sodium carbonate (anhydrous) 5 g *add distilled water to make 1 L Processing time 6 minutes. Developing times may increase with harder gelatin. =CWC2= From Jeffrey: CWC2 DEVELOPER and PBU-AMIDOL BLEACH - for all types of HOLOGRAMS CWC2 - two-part DEVELOPER PART A solution *500 ml. warmed distilled water. *(Pyro)Catechol 10 grams *L-Ascorbic Acid (Vitamin C) 5 grams *Sodium Sulfite (anhydrous) 5 grams *Urea 30 grams PART B solution *500 ml. warmed distilled water. *Sodium Carbonate 30 grams Part A is good for one month, Part B indefinitely. Add equal parts A & B to activate just a minute or two before use, just enough to cover one hologram. Mixed solution is active for 20 minutes. Discard after one use to assure each hologram has optimum development. Develop time:at least TWO minutes @ 68 degrees F. with constant agitation (AGFA). FIVE minutes for low power lasers, for HRT plates and PFG-03M plates. Rinse in distilled water. View a green safelight through rinsed plate to judge density - some variation is OK. Adjust exposure/developing time to achieve a final developed density of: *D 1.5 - 2 - medium gray (for an unbleached transmission hologram) *D 2 - 3.5 - very dark (reflection holograms). *D 4 - appears mostly opaque (good for HRT reflection holograms). Do not use fixer if it will be bleached (reflection holograms are usually bleached). Notes on developed density - this stage is where you figure if exposure, ratio, gleam spots, beam centering, even illumination, and overall light levels and their recorded patterns are OK for the next shot as well, or need adjustment. After the plate is bleached clear, these clues are gone. Although dark, wet, and hard to see, observation of different gray levels is important, hopefully understanding what caused each visible pattern. A good safelight is important. My favorite is a commercially available four-foot fluorescent fixture with plastic tube filters. =PBU-AMIDOL re-halogenating BLEACH= (Phillips Bjelkhagen Ultimate) *Potassium Persulfate 10 grams *Sodium Bisulfate (or Citric Acid) 10 grams *Potassium Bromide 20 grams *Cupric Bromide 1 gram *Amidol (- add last ! -) 1 gram Mix one at a time, in sequence, into 500 ml. warmed distilled water, then add another 500 ml. distilled water to make 1 liter. *Wait at least 30 minutes for chemical activation. *Bleach unfixed plate for 3-5 minutes @ 68 degrees F. 'til clear + 2 minutes. Rehalogenating (and image brightening) continues after clearing. *Rinse, rinse, rinse in distilled water. *With a drop of Photo-Flo in the final rinse, squeegee. *Air dry, a low-heat blower or drying cabinet for around 15 minutes - not too fast, not too slow. An acetic acid rinse after bleaching may help reduce print-out (the emulsion will darken a bit after you run out in the daylight to see your image). I prefer to avoid intense sunlight until aged a few days. Re-bleaching later will partially clear a darkened plate and give some immunity to further print-out. Bleach can be re-used a few times, and is usually good for two weeks - red color will fade to clear, indicating exhaustion. *Beware sediment as it ages - do NOT attempt to re-mix before each use - decant and do not dump dregs out onto emulsion. *Bleach will leave permanent purple stains on everything - handle carefully ! Many thanks to Cooke and Ward, Hans Bjelkhagen, Nick Phillips and Ed Wesly for the many trials to attain the basic formulation. -------------------------------------------------------------------------------- =GP-9= *Phenidone .026 g *Hydroquinone .665 g *Anhydrous Sodium Sulfite 13 g *Potassium Hydroxide 1.38 g *Ammonium Thiocyanate 3.12g *Distilled Water 1 L =GP-61= Transmission *Distilled Water 700cc *Metol 6 g *Hydroquinone 7 g *Phenidone .8g *anhydrous sodium Sulfite 30g *Anhydrous Sodium Carbonate 60 g *Potassium Bromide 2 g *Sequesterine Agent 1 g *Water to make 1 L =GP-62= Reflection (use Bleach) Part A *Distilled Water 700 cc *Metol 15 g *Pyrogallol 7 g *Anhydrous Sodium Sulfite 20 g *Potassium Bromide 4 g *Sequestrene Agent 2 g *Water to make 1 L Part B *Distilled Water 700 cc *Anhydrous Carbonate 60 g *Water to make 1 L =Kodak D-8= *Ascorbic Acid 18g *Sodium Hydroxide 12 g *Sodium Phosphate Dibasic 28.4 g *Distilled water 1 L Just before use add Phenidone .5 g =Transmission bleach= *Water 1 L *Potassium Ferocyanide 1 tablespoon *Potassium Bromide 1 tablespoon *or *Cupric Bromide 1 tablespoon (not both!) =Reflection bleach= *water 1 L *potassium Bromide 30 g *Borax 15 g *Potassium dichromate 2 g Just before use add PBQ (p-benzoquinone) 2 g (good for 15 minutes) =PBQ= *Water 1 L *Mercuric Chloride 1 tablespoon *Potassium Bromide 1 tablespoon or *Water 1 L *Potassium Bromide 30 g *Boric Acid 1.5 g *PBQ 2 g Good for only 15 minutes! or *Sulphric acid 1 g *potassium Bromide 5g *Methyl Paraben 2g *Hydrogen Peroxide 4 g (you have to figure the weight of the Hydrogen peroxide in you solution!) *Potassium Alum 5g (hardener) *PBQ 1 g *Phenosafranine 1g (desensitizer) =GP-431 Bleach = *Water 600 cc *Ferric Nitrate 8-hydrate 150 g *Potassium Bromide 30 g *Dissolve .3 g of Phenosafranine in 250 cc of methanol and then add. *Water to make 1 L Dilute 4 parts water to 1 part gp-431 before use. =Leroy= by Martin Since some are interested in the old Leroy paper, here is my - rudimentary - translation: Excerpts from: M.N. Leroy, Préparation et sensitométrie de plaques photographiques à grain très fin (plaques pour la photographie interférentielle), Paris 1929 ==== Summary ==== The following note presents a new way for the making of fine grain photographic emulsions, derived from colloidal silver, that allows for the spectral recording of remarkable brightness, comparable to Lippmann emulsions. It (the note) summarizes certain results achieved with silver chloride, bromide and iodide. The study of the density graphs indicates a maximum sensitivity at a particular lambda for each of the three cases and depends on the molecular weight of the specific salt used. Having established the characteristic graph of each emulsion at certain spectral levels, the author is studying the variation of gamma as a function of lambda, and points out that these plates, (though) having the qualities of any common plates, they can be sensitized to any wavelength and t can be used for color photography. The present study tried to establish the sensitometric characteristics of Lippmann plates, prepared according the formula of the ingenious inventor of the only direct recording method of color photographs. The results indicated too many variations and lacked the desired consistency. This is certainly due to fluctuations usually occurring (even) with the same composition (differing but on agitation, temperature, filtering, washing etc.). In one case, instead of being sensitive to the wavelength showing the strongest diffraction, we even observed sensitivity to radiation all over the visible spectrum. Without adding any sensitizers, it all the same behaved like an orthochromatic plate and, this was consistent for all plates of that batch, we do not have an explanation. According to Mr. Cotton, who advised us to use colloidal silver, on which grounds he had managed to make plates for interference color photography, we succeeded to get light sensitive layers of very small grains and of great consistency indicated by the measurements we carried out in the case of silver chloride, bromide and iodide. ==== Preparation of the plates ==== To a tepid solution (filtered warm) of 2.5g special gelatin in 50 cm3 distilled water, 3 cm3 of a 10% colloidal silver solution are added. The resulting liquid of brown color, is poured on glass plates according to the methods used for collodion. The plates, arranged horizontally until gellation, are subsequently dried protected from dust. These operations are carried out under normal light, thus allowing for the production of a stock to be used occasionally as needed. The transformation of the colloidal silver into halide salts is carried out under subdued light, such as that of a candle or some reduced gaslight. The plate is introduced into a bath for which - after numberless trials - we established the following compositions (note: the quantities given do not correspond with the completed reaction but proofed to work most conveniently for our experiments): {| class="wikitable" |+Chloride plates |- |align="left"|sodium chloride||align="right"|2g |- |align="left"|copper sulfate||align="right"|2g |- |align="left"|water||align="right"|1000g |} {| class="wikitable" |+Bromide plates |- |align="left"|potassium bromide||align="right"|2g |- |align="left"|copper sulfate||align="right"|2g |- |align="left"|water||align="right"|1000g |} {| class="wikitable" |+Iodide plates |- |align="left"|potassium iodide||align="right"|2g |- |align="left"|copper sulfate||align="right"|2g |- |align="left"|water||align="right"|1000g |} "Bromination" is taking place equally well by using a diluted solution of cupric bromide; cupric chloride however, produced an opaque layer as well as did chlorine water (?) or iodine solution. During the preparation of the iodine (? rather cupric iodide I suppose - MM) bath, a precipitation of cupric iodide is forming which can be eliminated by filtering. As soon as the reaction stops - that is to say, when the yellowish color has vanished - one has to wash the plate, turned transparent meanwhile, exhaustively. At this stage the plates are very little sensitive. A means to this nuisance is to insert them into a second bath of 50g water to which 2g of a silver nitrate solution (0.5g AgNO3 per 100g water) were added during 1 minute. They are washed with distilled water and dried in darkness. The developer has the following composition: {| class="wikitable" |- |align="left"|water||align="right"|100ml |- |align="left"|sodium sulfite||align="right"|4g |- |align="left"|Amidol||align="right"|0,3g |- |align="left"|Potassium bromide||align="right"|0,75g |} The plates are fixed in sodium thiosulfate. ==== Conclusions ==== Due to the preliminary results, this study represents only some sort of beginning. Nonetheless, we are thinking the constants (?) introduced by Hurter and Driffield into photographic practice, can be applied to the fine grain plates we prepared. We will continue our work, systematically studying the use of chemical sensitizers and try to realize a perfectly orthochromatic "interference" plate. We meanwhile like to point out that the silver bromide plates prepared by flowing, are easily sensitized orthochromatically and allow for spectral recordings of the same brightness as Lippmann plates. The same is also valid for chloride. However, the sensitizers ("orthochromatisants") successfully applied to chloride and bromide, did not show any effect on iodide. Concluding this work, it is an pleasant duty to express my appreciation to professor Cotton (directeur du Laboratoire des Recherches physiques à la Sorbonne), for his support and interest. I equally thank my teacher, Mr. de Watteville, who introduced me into the delicate technique of interference photography... etc. =Making your own plates= by Jeff Blythe Diffusion method - estimated cost by Jean (no login) As promise, I post my estimated costs table for a batch of 20 holoplates made with the Jeff Blyth's diffusion method. Silane, LiBr, Pinacyanol come from Sigma-Aldrich All prices are in Euro (1 Euro ~ 0,97 USD) {| border="1" |- !Chemical !Price/Quantity !Diluted quantity !Quant/20 plates !Price/20 plates |- !AgNO3 (6%) |align="right"|18,11/10 g |align="right"|166 ml |align="right"|60 |align="right"|6,55 |- !LiBr (3%) |align="right"|11,2/100 g |align="right"|3300 ml |align="right"|300(*) |align="right"|1,02 |- !Pinacyanol (0,1%) |align="right"|16,81/250 mg |align="right"|250 ml |align="right"|7,5 |align="right"|0,5 |- !Ascobic Acid (1%) |align="right"|2,11/30 g |align="right"|3000 ml |align="right"|300(*) |align="right"|0,21 |- !Gelatin (15%) |align="right"|9/1000 g |align="right"|6666 ml |align="right"|100 |align="right"|0,14 |- !Chrome Alum (2%) |align="right"|3/100 g |align="right"|5000 ml |align="right"|300(*) |align="right"|0,18 |- !Silane (1%) |align="right"|31,16/100 ml |align="right"|10000 ml |align="right"|100 |align="right"|0,31 |- !Glass (4x5) |align="right"|12,5/20 |align="right"| - |align="right"|20 |align="right"|12,50 |} Total for 20 plates - - - 21,41 or 1,07/plate (*) I assume I change for each batch : - LiBr + Dye bath - Chrome Alum hardener - Ascorbic Acid sensitizer But please pay attention of this following note from Jeff about the LiBr bath : "please note that I myself reuse the dye/LiBr baths several times. A little bit of precipitate in the bottom of container (it is only AgBr) can be left there and the liquid poured off or the solution just filtered. So you can make many plates if you want to for the initial expence. The quantity of subbed plates you could make is enough for an industrial production run!" I don't calculate price for water, acetone and methanol because those products are cheap. First batch can seems expensive because you need to purchase relatively big quantity in regard of the used quantity and you need to some laboratory material. Hope this can give you the curiosity to test this easy method. Jean PS : my 2nd batch has failed because I don't care to dry plates enough after Chrome Alum bath! Results was presence of chrome salt who fog the plates. I'll try hardening gelatin with a bath of 1% formalin in DI water. =SM-6= *Sodium Hydroxide 12.0g *Methyl Phenidone 6.0g *Ascorbic Acid 18g *Sodium Phosphate (dibasic) 28.4g *Water to 1L =Stop Bath= *Acetic Acid 20g *Water to 1L =Safe Ferric Brilland Bleach= ( rehalogenating Bleach designed by brilland) *Ferric III Sulfate 30g *Citric acid 30g *Potassium Bromide 30g *Deionized water to 1000 cc. You can use it and store it for a very long time at room temperature. It gives very low noise results. =AAC= *Ascorbic Acid 18g *Sodium Carbonate to give a pH of 10.5 *Distilled Water 1L =AGFA 80= *Metol 2.5g *Soduim Sulfite (anhydrous) 100g *Hydroquinone 10g *Potassium Carbonate 60g *Potassium Bromide 4g *Distilled Water 1L =GP-8= *Metylphenidone .2g *Hydroquinone 5g *Sodium sulfite (anhydrous) 100g *Potassium hydroxide 10.6g *Ammonium thiocyanate 24g *Distilled water 1L Mix 60 ml of developer with 400ml of distilled water. Develop for 6 minutes at 20C. =GP-2= *Metylphenidone .2g *Hydroquinone 5g *Sodium sulfite (anhydrous) 100g *Potassium hydroxide 5g *Ammonium thiocyanate 12g *Distilled water 1L Mix 15ml of developer with 400ml distilled water. Develop for 12 minutes at 20C without agitation. Develop with plate facing up and DO NOT agitate (you don't want to move the disolved silver away from the plate). =CPA1= *Metylphenidone .02g *Hydroquinone .65g *Sodium sulfite (anhydrous) 13g *Potassium hydroxide 1.4g *Ammonium thiocyanate 3.1g *Distilled water 1L Develop for 2 minutes at 22C. 3 seconds of initial agitation. =N6= *Metol .5g *Sodium Sulfite (anhydrous) 100g *Hydroquinone 45g *Sodium carbonate 30g *Potassium thiocyanate 5g *Potassium bromide 10g *Distilled water 1L Mix 1 part developer to 8 parts distilled water. =F1= *Amidol 4g *Sodium sulfite (anhydrous) 30g *Silver nitrate 3g *Potassium bromide 2g *Sodium thiosulfate 45g *Distilled water 1L Develop for 8 minutes. Fix for 2 to 3 minutes. =F2= *Metol 10g *Sodium sulfite (anhydrous) 100g *Silver nitrate 2g *Potassium bromide 2g *Sodium thiosulfate 30g *Distilled water 1L Develop for 30 minutes. No fix is required. =MM-Collo 1= From Martin: The best formula I ever made for a colloidal developer was: *Metol.............................2g *Ascorbic acid.....................7g *Methylphenidone.................0,5g *Potassium bromide.................3g *Potassium carbonate..............20g *Ammonium thiocyanate..............2g *Distilled water...................1L Dilute 1 : 50 or up to 1:100 (with distilled water) On PFG-03M it yielded extremely fine grains, resulting in a yellow emulsion (compared with the orange/red layer produced upon GP development). Development is quite slow, requiring > 30 min @ 20°C. =VR-P developer= *Sodium Sulphite anhydrous 194 g *Hydroquinon 25 g *Potassium Hydroxide 22 g *Methylphenydone 1.5 g *Potassium Bromide 20 g *Potassium Metaborate 140 g *1,2,3-Benzotriazole 0.1 g *Distilled water to 1 L Working solution: 1 part of VR-P Developer + 6 parts distilled water =Phillips' Ferric Nitrate Bleach= *150 g Ferric Nitrate *33 g Potassium Bromide *20 g Glycerol *300 mg Phenosafranine *500 ml Isopropyl *500 ml Distilled Water =Phillips' PBQ-1 Bleach= *2 g PBQ *30 g Potassium Bromide *1.5 g Boric Acid *1L Distilled Water =Phillips' Ferric EDTA= *30 g Ferric Sulfate *30 g Di-sodium EDTA *30 g Potassium Bromide *10ml Sulfuric Acid *1L Distilled water =D-14H= From Hans: I got this formula from http://silvergrain.com/labs/Print_Developer_Recommendation?title=Print_Developer_Recommendation It does not to be mixed in a A and B solution and I have found that it works just as good as the Ultimate safe holographic developer. I made on adjustment to the original formula in that I left the KBr out because I don't think that there should be KBr in a holographic developer. Development time is about 1.5 minutes. *Dimezone S 0.2g *ascorbic acid 6.0g *sodium sulfite, anhydrous 12.0g *sodium carbonate, monohydrate 30.0g *triethanolamine, 99% 5.0ml *salicylic acid 0.5g *water to make 1.0 liter target pH 10.4 ± 0.2 =Ascorbate Developer= But I contend that the best way of dealing with ascorbate developer stock and it is a way we have been successfully using for some years in our labs is to "A and B" it. For A we have a 500ml bottle with: *20g ascorbic acid *3g Metol (4-methylaminophenol sulfate) *and top it up with 500ml deionized water for B we have a 500 ml bottle of *50g sodium carbonate anhydrous *15g sodium hydroxide top up with 500 ml deionized water. (This one should be labeled "very caustic" ) Just use equal volumes of A and B from then on. Now there are 3 bonus points for using Metol instead of phenidone. 1) is that phenidone is quite a strong silver halide solvent and tests have proved that metol gives brighter holograms. 2)The second point is that metol has a hardening action on gelatin and its effect on speeding up the development time over what you would have with just alkaline ascorbate means that even notoriously soft emulsions juch as PFG-03 can be in and out of the developer bath into a stop bath (~5% acetic acid ) in around 20 seconds, before the gelatin is seriously attacked. Assuming of course your exposure level was good enough. 3) Metol is a weaker reducing agent or developer than alkaline ascorbic acid. When Metol gets oxidized it goes really dark brown so this is a useful indicator to tell you when your bath is exhausted because it wont go severely dark until most of the ascorbate has been oxidized. A mild yellowing like weak tea is quite OK . Dont forget to use the floating dish method of 2 closely fitting plastic dishes with the upper dish keeping most of the air out as it floats and acting as convenient agitator as well. Acid ascorbate in the stock soln A will not seriously oxidize for a year. (Slight yellowing is perfectly OK . ) jeff =Metol-Ascorbate developer courtesy of Laser Reflections= The formula is as follows: Metol-Acorbate Developer (Part A + Part B) Part A: Metol 10g Ascorbic Acid 80g Water to 1000ml Part B: Sodium Carbonate Anhydrous 120g Sodium Hydroxide 14g Potassium Bromide 4g Water to 1000ml Use it in combination with a Fe-EDTA bleach - a safe, stable bleach which has a long shelf life. Fe-EDTA Bleach EDTA (2Na) 30g Fe(III) Sulfate 30g Potassium Bromide 30g Sodium Hydrogen Sulfate Crystals 30g Water to 1000ml =Sergey Vorobyov's developer - OD-1= New postby Gall » Mon Nov 08, 2010 12:05 pm Some time ago Mr. Vorobyov invented a developer for silver-halide holograms that does not contain any rhodanides. It is ideal for both beginning and advanced holography. The original Russian article is here: http://www.holography.ru/tech8rus.htm Original formula: *Metol = 2 g *Sodium Sulphite (anhydrous) = 25 g *Hydroquinone = 5 g *Borax B[sub]4[/sub]H[sub]4[/sub]Na[sub]2[/sub]O[sub]7[/sub] = 2 g *Sodium Thiosulfate (photographic fixer) = 6 g *Water = 1000 ml Here sodium thiosulfate replaces rhodanide. It dissolves AgBr so that the process is the physical one and not the chemical one. Simplified formula - made from Kodak D-76, ideal for beginners (image is slightly worse but still works): *Take Metol and Hydroquinone mix from two ready-made 0.5l D-76 packages (2x[1 g + 2.5 g]). *Take Sodium Sulphite and Borax mix from one package (1x[50 g + 1 g]). *Add 6 g (one teaspoon) neutral fixer (Sodium Thiosulfate). This will result in following: *Metol = 2 g *Sodium Sulphite (anhydrous) = 50 g *Hydroquinone = 5 g *Borax B[sub]4[/sub]H[sub]4[/sub]Na[sub]2[/sub]O[sub]7[/sub] = 1 g *Sodium Thiosulfate (photographic fixer) = 6 g *Water = 1000 ml Dissolve Metol and Hydroquinone first in some warm (40-45 centigrades) water, then add everything else, add water to 1000 ml and filter the solution. The resultiong solution should be mixed with water 1:4 before use. Develop around 10 minutes at 18 centigrades. =Zip1= For transmission Holograms. I have been using my own developer for the last three years which is extremely active requiring much shorter exposure times than others (JD-2, JD-4, Pyro, etc). Used it for reflection and transmission on Slavich (especially VPR-M) and Agfa films and plates (8E75/56). Sometimes EDTA and sometimes Dichromates bleaches: Zip1: *Metol 1gr, *Hydroquinone 1gr, *Phenidone 0.5gr, *Sodium Sulphite 30gr, *Ascorbic Acid 10gr, *Potassium Hydroxide 30gr, *water to make 1 litre Dave I've used it for reflections in place of the pyro developer and with the dichromate bleach. It also over comes the hassle of accidently getting stained fingers with the pyro developer if you forget to put the rubber gloves on. The main benefit I've found is that the image brightness is on a par with the other developers with the bonus of shorter exposures. The mix of the Metol, Hydroquinone and Phenidone with the Potassium Hydroxide is quite an active combo. I'm not really surprised and certainly these chemicals are cheaper than pyro and catechol.. 6cadb9f85597c4313be29711a8033f108b907ab5 0 508 1167 1166 2013-05-12T02:54:50Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:SBR.JPG]] Side View The expanded laser beam, diverging, is coming in from above left. You can see with only an approximate 50 degree reference angle, the plate needs to be considerably larger then the object such that the top of the plate does not bisect the object (object shadow is very near top of plate shadow) or one could choose a shallower object. With the addition of black tape across the top of the plate (not shown here) to elliminate internal reflections, the top edge of the plate shadow whould be thicker and darker. [[Image:SBR2.JPG]] Front View The expanded laser beam, diverging, is coming in from above and just to right of camera view. 8fd7b89a7a13b7fde5e663319adb824e977e0464 0 509 1169 1168 2013-05-12T02:54:50Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:SBT.JPG]] Side View The expanded laser beam, diverging, is coming in from above left. You can see that the object needs to be far enough away so that there is adequate lighting that can be seen by the plate but this does waste light. [[Image:SBT2.JPG]] Front View The expanded laser beam, diverging, is coming in from above and just to right of camera view. A simple mirror in the set up to gather some of the wasted light and redirect it to the object would be beneficial. d3422bfe838280c3d33dcc2b97da0debb725daab 0 510 1171 1170 2013-05-12T02:54:50Z Jsfisher 1 1 revision wikitext text/x-wiki When Applied Holographics were in full swing with that holocopier I remember sitting in the office of the leading light behind that enterprise,Hamish Shearer. We were both eying his nice goldfish in their aquarium when I had an idea. “Why don’t we make a pulsed portrait of them ?” I asked. We duly got a large 5 litre glass beaker filled it with water and Hamish carefully caught 2 of the smaller fish and we took it over to a spare ruby pulsed laser unit in a room there. There was no safelight in that room if I remember rightly but I think we got enough light in to set up the experiment with an AGFA 8E75 plate by leaving the door slightly open. I simply rested the plate ( I think it may have been a rather expensive 10 x 8” ) against the beaker to shoot a simple Denisyuk in a single spread beam pulse of Ruby 694nm. However for obvious health and safety reasons before we donned our goggles ready to shoot we had to lock the door , and this meant shooting the fish in pitch black darkness. I then put the exposed plate in a box and took it over to the lab to process. Then as we both eagerly watched the finished plate under a spot light as it dried under a hot hairdryer we saw…………….. NOTHING! or almost nothing except for a bit of the brand name PYREX. Not the slightest hint of a fish. We then repeated the operation with another ($50?) plate. The result was again no sign of a fish! I was utterly perplexed….and pretty embarrassed and annoyed, I was there as a supposed expert on making and processing Denisyuks , How could this be happening ? The fish couldn't possibly be moving too fast for a 20ns pulse and in any case they would have made a shadowgram on the piece of white card we put behind the beaker for the second shoot. Then we did some testing by turning the room lights on and off. The truth then was revealed .. ......... The moment the room went black those clever little bastards dived down and laid flat down on the bottom of the beaker!! ----obviously some sort of evolved survival mechanism to protect themselves from powerful alien laser beams presumably. We did on the third go finally manage to get our pulsed portrait of the fish but unfortunately…. it HAD to include an unedifying view of a Hamish arm as his hand had to rest on the bottom continually tickling the fish to keep them up in the picture frame. 6026a01e3fcc13905662cce2c97e6f14fbe1136f 0 511 1173 1172 2013-05-12T02:54:51Z Jsfisher 1 1 revision wikitext text/x-wiki '''SOGOKON' A. B.''' '''LIPPMANN PHOTOGRAPH''' ON THE LAYERS OF THE BICHROMIZED GELATIN Are investigated the spectral characteristics of the Lippmann images, obtained on the layers of the bichromized gelatin (BKHZH). It is shown that the color of image depends not only on the wavelength of emission, but also on its intensity. This is connected with the heterogeneous swelling of gelatin and with a change of its structure in the nonirradiated sections with the rapid dehydration. The uncommon properties of Lippmann photographs on BKHZH can be used for preparing the selective mirrors, for mapping of graphic information, and also for registration and image processing. Is known [1] the method of obtaining the colored images, based on the registration of standing waves in the volume of thick transparent photographic emulsion. The period of the registered interference structure is unambiguously connected with the wavelength of that falling to the layer of emission, which ensures the correct color reproduction of the photographed image with the illumination by its white emission. Because of the great technical difficulties in its time this method did not obtain wide application. The development of holography led to the creation of the fundamentally new technique of experiment and new recording media. Appeared communications about the record of Lippmann photographs on the contemporary emulsions of the type LOI-2 [ 2,3 ] and on the layers of the bichromized gelatin (BKHZH) [ 4,5 ]. Purpose of this work - study of the special features of the Lippmann photographs, obtained on the layers BKHZH, the mechanism of shaping of images and possibilities of their practical application. '''Procedure and the results of the experiment''' For the preparation is layer BKHZH the basis it is undertaken the method Lina [6]. The holographic plates Of pe-2 and LOI-2 they fixed in the acid fixative, washed in the running water and dried at room temperature. The sensitization of the dried plates was conducted directly before the exhibition. For this plate was immersed on 5-15 min in 1-5%- ache the solution of dichromate of ammonium and after its runoff dried in the jet of hot air or in the cabinet drier at a temperature 100-150°. Duration of drying 3-5 min. [[Image:LippmannFig1.jpg]] Fig. 1. Installation diagram for the contact printing Lippmann photographs; 1 - luminous source (laser or mercury-vapor lamp), 2 - lens, 3 - negative, 4 - layer BKHZH, 5 - the mirror The installation diagram for the printing of Lippmann photographs is given in Fig. 1. They direct the extended laser beam to the negative, located before the recording medium, the passed emission is reflected from the flat mirror and, being extended in the opposite direction, is formed in the volume of the recording medium the standing wave, whose amplitude depends on the transmission of negative. As the radiation sources were used the lasers LPM-YY (442) and LIE -21 (337 nm) and mercury-vapor lamp DRSH-2SHCH0 (365, 436 nm). Furthermore, by means of the usual photographic enlarger was achieved the direct projection printing of enlarged images. The regime of working the plates exposed practically was differed in no way from the regime of working BKHZH for obtaining the holograms [ 7 ]. The images, obtained employing the procedure given above, have a number of interesting properties. With the examination of image in the reflected light (a subnormal incidence in the light) different sections of image depending on the density of initial negative acquire different color. Under the transparent sections is obtained the image of dark-blue color, while under the opaque - red. The semitones of negative are transferred by nuances within the limits from the orange to the green. Hence it is possible to draw the conclusion that the period of the interference structure, fixed in the layer BKHZH, depends both on the wavelength of emission and on its intensity. If we arrange Lippmann imprint on the sheet of black paper and to examine at large angle, then usual black and white image is observed. Under the transparent sections of the negative of gelatin it remains transparent, while under the opaque acquires milk-white tone. In this case the image is constructed not due to the luminous absorption, but due to its scattering, which resembles the properties of images on the vesicular materials [8]. For investigating the dependence of the color of image on the exposure level on one plate they achieved a number of exposures by the uniform collimated laser beam or photographed the image of sensitometric wedge, and then the spectra of the transmission of the obtained images were measured. [[Image:LippmannFig2.jpg]] Fig. 2. Characteristics of Lippmann the image: and, g - dependence of the spectra of the transmission of the images from the exposure level with the record by the emission heliumcadmium (442 nm) and nitric (337 nm) lasers; b and d - dependence of the density of image on the exposure for the same wavelengths; C - the dependence of the color of the image from the logarithm of exposure (curve 1 - 442, curve 2 - 337 nm); e - dependence of the half-width of the spectra of the transmission of the images from the exposure (1 - 442, 2 -337 nm) Fig. 2 depicts the spectral characteristics of the images, obtained on the plates Of pe-2, sensitized by the 1%- by the solution of dichromate of ammonium during the exhibition by the emission of lasers LPM-YY (Fig. 2, A) LIE -21 (Fig. 2, g). From the analysis of spectra follows that depending on exposure level the width of reflection spectra (Fig. 2,e) changes, the wavelength of the maximum of reflection (Fig. 2, c), and also the density of image (Fig. 2, b, d). It should be noted that the wavelength of the maximum of reflection with the long exposures does not correspond to the wavelength of the emission of record. This is connected with the fact that in the process of treating the layer an increase in the period of interference structure occurs. The wavelength of the maximum of reflection linearly depends on the logarithm of exposure (Fig. 2, c), which gives the possibility to write down [[Image:LippmannEq1.gif]] (1) where - the wavelength of the maximum of reflection with the high energy of exposure (wavelength of saturation), H - energy of exposure, k - constant of proportionality, which can be interpreted as the coefficient of the color contrast. With the conversion of the color of image occurs a change in its density (Fig. 2, b, d). These dependences are analogous to the characteristic curve of blackening of the usual recording media. However, the photographic latitude of linear section is considerably less, and in the field of the long exposures is observed the especially large spread of experimental points, which it is not possible to explain by error of measurements. It is possible to assume that the dependence of image in the region of saturation bears the oscillitory nature, for example, as shown in Fig. 2, d. '''Mechanism of the formation of the images''' In the process of the preparation of plates for the sensitization they prolonged time (about 1 h) find in the water. As a result of this gelatin it swells, long protein molecules untwist and they attempt to form the linear arrays. To molecules, which are been located on surface layer, this succeeds to the larger degree than for molecules, which are located in the depth, since they to a lesser degree experience the resistance of adjacent molecules. In the razbukhshem layer is obtained the heterogeneous tanning, which grows from surface layer to the base layer. The surface molecules of gelatin, which formed the linear arrays, no longer can accomplish work, they occupied energetically advantageous position, while molecules, which are located in the depth of layer, they have a certain reserve of potential energy, since interaction of some with others and with the molecules of tanning matter does not make possible for them to be erected into the linear arrays. Tanning can be determined by value, to the inversely proportional work, accomplished by molecules with the working in the water. Layer is not tanned, if molecules realize entire stored potential energy, and it is tanned, if potential energy with the working in the water does not realize. The potential distribution energy along the thickness of the razbukhshego layer can be schematically presented, as shown in Fig. 3, A. Let us examine the processes, proceeding with swelling of those exposed it is layer. In this case we consider that the photochemical transformations Cr(.VI) into S.r(.III) in the gelatin occur in accordance with the model, described in the work [ 9 ]. The number of photos-seam between the molecules, which were being formed in the antinodes of standing wave, is small with low energies of exposure, summary binding energy between them is also small, and the potential distribution energy of the molecules of the swollen layer takes the form, shown in Fig. 3, b. furthermore, with the prolonged working in the water together with swelling of layer in the knots of standing wave can occur the local dissolution of gelatin, i.e. the hydrated molecules acquire relative freedom, changing the structure of gelatin, but they cannot leave layer because of the tanned sections in the antinodes. In the works [ 10,11 ] it is shown that the structure of gelatin changes both with working of layer in the water and in the process of drying. Therefore with the working by isopropanol a change in the structure of gelatin in the knots and the antinodes occurs differently, i.e. with the rapid loss of water of molecule they do not manage to return to the initial state and they are forced to form the new molecular network, different from that, which is obtained with usual gel-NII - Scientific Research Institute or slow drying. In the knots of standing wave gelatin density decreases due to an increase in the volume of layer, while in the antinodes it increases due to structure change under the action of that forming Of s.r(.III). As a result of gelatin the elasticity loses, and in the layer the increased period of interference structure is fixed. With an increase in the exposure grows modulation of potential energy of the razbukhshego layer. The number of constant-phase surfaces, recorded in the layer, increases (Fig. 3, in, g, d), the width of reflection spectra and displacement into the red region decrease, and diffraction effectiveness rises. By a change in the structure of gelatin it is possible to explain the formation of black and white image. The destructured sections strongly scatter light, which gives milk-white form to them. '''Consideration of the results''' Uncommon properties of Lippmann photographs on the layers BKHZH can be used for preparing the selective mirrors, for obtaining the pseudo-colored slides from the black and white negatives, for registration and image processing. The possibility of using the Lippmann photographs as the selective mirrors directly follows from Fig. 2. The wavelength of reflection and half-width depend on exposure level. In this case the reflection coefficient attains 99%, which makes it possible to use such mirrors in the resonators of lasers, in the Fabri-Perot interferometers, and also as the beam splitters in the holographic devices. The cost of them is considerably lower than interference dielectric mirrors, and in this case is a possibility of preparing the mirrors of practically any sizes and creation of any distribution of spectral characteristics in the plane of mirror. [[Image:LippmannFig3.jpg]] Fig. 3. Diagram, which elucidates the dependence of the period of the interference structure from the exposure level: and - the distribution of the tanning in the razbukhshem unexposed layer; b, in, g, d - modulation of the tanning in the razbukhshem layer depending on the exposure The pseudo-colored slides, obtained from the black and white negatives, can be used for mapping of graphic information, for example diagrams, tables, graphs. Slides can be demonstrated both in the transmitted light by usual kadroproyektorom and in that reflected with the application of an epidiascope. The second version should be given preference, since with this more fully is used color range and is reached higher high-contrast image. With the printing from the black and white negatives the value [[Image:LippmannEq2.gif]] and [[Image:LippmannEq3.gif]] in equation (1) can be represented in the form [[Image:LippmannEq4.gif]] and [[Image:LippmannEq5.gif]] where - the intensity of light, which falls to the negative, the smallest density of negative (density of veil), density of image, time of exhibition. After substituting these values in (1), we will obtain [[Image:LippmannEq6.gif]] whence it follows that a change in the color in the Lippmann photograph is linearly connected with the density of negative. Recently increasingly more frequently is used the idea of complex spatial distributions of different physical quantities by means of the conditional it is color, for example, with digital processing of images [ 12 ]. To Lippmann photographs on BKHZH this property is inherent by their nature itself. In this case Lippmann "painting" has the advantage that the obtained image can be subjected to further optical working. Examining the pseudo-colored image through the light filter with the passband [[Image:LippmannEq7.gif]], we will observe the details of initial image, which are located in the density range [[Image:LippmannEq8.gif]]. By a change in the wavelength of light filter it is possible to separate the image details interesting, and by changing its half-width - range of densities interesting. If the image, observed through the interference light filter, photographed on the contrasting photographic material, then it is possible to obtain the images of the lines of identical density - equidensities. For the illustration is carry ouied processing the image of planet Jupiter. For this from the astro-negative they printed image with an increase by the layer BKHZH. The obtained image they photographed through the interference light filter with [[Image:LippmannEq9.gif]] = 640 nm and [[Image:LippmannEq10.gif]]= 90A. Fig. 4, and depicts the photograph of initial image, while on Fig. 4, b, C - to a series of photographs with the different angles of the slope of interference light filter, i.e. with the different [[Image:LippmannEq9.gif]] and [[Image:LippmannEq10.gif]]. It is evident that even under the conditions for the incorrectly set experiment (reconstruction of the wavelength of light filter was achieved via its inclination) on the obtained images it is possible to reveal more interesting details, than on the initial negative. [[Image:LippmannFig4.jpg]] Fig. 4. Isolation of equidensities on the image of planet Jupiter: and - the imprint of siskhodnogo astro-negative; b - photograph of the Lippmann image, obtained with the interference light filter with the different angles of its inclination in the reflected light; C - the same, but in the transmitted light However, with the two-stage process unavoidably are shown distortions and noise, which appear during the first stage of registration. The granularity of images on Fig. 4, b is caused by the granularity of the material, on which is registered initial negative. Therefore the considerably larger volume of information can be extracted with processing of the Lippmann images, obtained with the direct registration. However, sufficiently small sensitivity it is layer FOR BKHZH it does not make possible to directly record the images of other astros-object, except the sun. The direct registration of Lippmann images possibly in biology. In this case the emission of lamp DRSH-2SHCH0 it is completely sufficient for obtaining the images with increase in 30-100x. Thus, the Lippmann photographs, obtained on the layers BKHZH with the use of sources of monochromatic light, have properties, substantially different from the properties of usual Lippmann photographs. This is connected with the special features of the recording medium: the period of the fixed interference structure depends not only on the wavelength of incident radiation, but also on its intensity. As a result the possibility of the single-valued conversion of the intensity of light in the color appears. Simplicity of the diagram of obtaining Lippmann photographs, possibility of using the sources with the small length of coherence and high diffraction effectiveness of images open the great possibilities of the practical application of this method. In conclusion the author considers as his pleasant duty to express appreciation To v. p. sherstyuk and L. ye. mazur for the valuable considerations, in. By a. kaminskoy and By l. ye. nikishinoy for help in conducting of spectrophotometric measurements and V. n. dudinova - for the kindly furnished astro-negatives. '''LITERATURE''' *1. Lippmann G S. R// Acad. Sci. 1891. V. 112. P 274. *2. Kostylev G. d. //Pis'ma in ZHTF 1976. Vol. 2. Of iss. 23. S. 1086. *3. Kostylev G. d., Ivanenko L. i.// the theses of dokl. IV All-Union conf. "photometry and its metrological guarantee". M., 1982. S. 119. *4. Sogokon' A. V.// the theses of dokl. IV All-Union conf. "non and uncommon fo- tograficheskiye processes". Blackcap, 1984. Vol. 1 of h. 2. S. 251. *5. Sogokon' A. b.// the theses of dokl. II All-Union conf. the "forming of optical image and the methods of its working". Kishinev, 1985. Vol. 1. S. 125. *6. Lin L n.// Appl. Opt. 1969. V 8. № 5. P 963. *7. Sjolinder S// Photogr. Sci. And Eng. 1984. V 28. № 5. P 180. *8. Nagornyy V. i., Chibisova N. p. //ufn. 1978. Vol. 19. S. 32. *9. Sherstyuk V. p., Dilung I. I. In the book: Fundamental bases of the optical of pamya- TI and medium. Kiev: Vishcha shk. 1982. Iss. 13. S. 33. *10. Levi S. m., Suchkova O. m., Suvorin V. V.// the jour. of nauch. and appl. photo- and kinema of tografii. 1984. Vol. 29. № 4. S. 252. *11. Murzinov A. V., Moiseyeva G. V., Stryukova e. g. and other// theses of the report republic of se- of minara "applied holography". Kiev, 1984. S. 49. *12. Usikov A. 4., Babichev A. A., Yegorov a. d., etc.// to conduct. AN OF UKRCSSR - UKRAINIAN SSR. 1977. № 10. S. 47. Kharkov state university im. a. M. of Gor'kiy 25c7666842e7392e25efaaaf5cbb3400fceb0244 0 512 1175 1174 2013-05-12T02:54:51Z Jsfisher 1 1 revision wikitext text/x-wiki Soldering a Laser Diode is a easy way to kill it! *The diode is very fragile. *Don't bend the pins, subject the diode to shock or static electricity. *Make sure to use a heatsink when soldering and use very thin wire for the connections. *Use very fine wire as the stiffness of the wire can bend a pin and break an internal wire. *Keep the leads from the driver to the diode short. *Shield as much of the wire as possible. 0825253ddfa92d8e9506df5879d951c6f4171aa3 0 513 1177 1176 2013-05-12T02:54:51Z Jsfisher 1 1 revision wikitext text/x-wiki As per Newport. D = Fw/a D = Pinhole Diameter F = Objective lens focal length w = Wavelength of laser (sorry no Greek letter on my keyboard) a = Beam radius input to lens More.... http://www.newport.com/store/product.aspx?id=3873&Section=detail&lang=1# ====Positioning a Spatial Filter with a Collimating Mirror==== For a collimated reference beam you need to place the spatial filter the sum of the focal lengths of the objective and the mirror apart. The focal length of the mirror is the focal ratio times the diameter. A great seat of the pants method is to take a piece of poster board and trace the diameter of the mirror on it. Rough set the optics and then place the card so the beam is reflected on to the card from the spatial filter at the largest distance you can find. If it fills the circle drawn on the card then you have a collimated beam. If it is larger you need to move the spatial filter back. If it is smaller you need to move the spatial filter closer. This is all easier and quicker to do without the pinhole. ====Aligning a Spatial Filter==== This is just a stub. Please add if you can. Aligning a spatial filter is a very difficult task the first time you attempt it. Taking an hour or two is not unusual. After a few tries it is quite easy. *Remove the Pinhole and the Objective. *Put a card after the spatial filter, and put a small circle on it around where the beam hits it. *Replace the Objective, and align the body of the spatial filter so the laser hits the center of the objective, as well as making sure the large disk of light from the objective is centered on the mark on the card. *Center the X and Y adjustments on the pinhole (so you have as much "room to maneuver" as possible.) and set the Z adjustment so the Pinhole is far away from the objective. *Re-install the Pinhole, so that the small blob of light (it will be dim) which is making it through the Pinhole hits the circle on the card. (My spatial filter holds the pin hole onto the XY stage with a magnet, its location on the magnet is a course adjustment.) *Now imagine the hour-glass shape of the light, starting out wide immediately after the objective, narrowing down to the focal point, and then widening out to where the pinhole is. Right now, the pinhole should be approximately centered down stream from the focal point. The adjustment process will walk the Pinhole up the hour-glass till its right on the focal point. *Move the Pinhole a little bit towards the objective, and watch the blob on the card. If the blob stays centered as you get closer to the objective, keep adjusting it closer to the objective. If it moves off center, stop and tweak the X and Y adjustments to re-center the blob. *Note how the blob moves in the same direction as the X and Y adjustments. If you go too far towards the objective and pass the focal point, the X and Y adjustments will reverse direction. *Keep moving the Pinhole towards the Objective, recentering the blob as you go. As you get closer, the adjustments will get touchier and touchier. If you lose the blob, move the Pinhole away from the objective till it re-appears, re-center, and then continue from there. *At some point, as you get closer to the focal point, rings will become visible around the blob of light. Those are Arie rings from the laser diffracting off the edge of the Pin-hole, and a good sign. *Keep moving the pinhole closer (and tweeking the X and Y to keep the blob centered) until the Arie rings merge with the blob. The blob will start getting brighter very quickly as you get close. *When the Arie rings merge with the blob, you're done. *If the X and Y adjustments reverse directions you've over-shot, the Pinhole is between the focal point and the Objective. Move the Pinhole away from the Objective, and then continue from there, just like if you lose the blob. The adjustments will be large as you start, perhaps an entire turn of a thumb screw. As you get closer to the focal point, a 5 degree rotation may overshoot. ====Homebuilt Spatial Filters==== When building home made spatial filters it is good to consider the very fine threads from [[http://www.thorlabs.com Thor Labs]]. They have taps and pre-made inserts. The pre-made inserts are much easier to use. The 100 TPI screws only have a thread height of .006" and it is hard to drill a hole that smooth. If you need to the proper method is to drill the hole under-size and ream it to size with a straight reamer. *[[John Klayer's Spatial Filter Plan]] ====Color Holography==== The assumption is that you have combined the beams into a single path and you have telescopes on the beams before the beam combiners so you can control their diameters. (The further assumption that the divergence of the lasers is the same.) As we will see you don't want all of the beams to be the same diameter! Quote: From Edmund: 1.0 Beam Spot Diameter (microns) = (1.27 * l * f) / D where, l = wavelength of laser (microns) f = focal length of objective lens (mm) D = input beam diameter (mm) 2.0 Pinhole size is then determined for the table (see note): Pinhole Diameter (microns) = 1.5 * Beam Spot Size Diameter (microns) So we notice that wavelength makes a difference. For this example we will use the wavelengths of: 650nm 532nm 473nm In order to make white we need the beam spot diameters of all three beams to be equal. If we miss, the balance of white will be uneven radially from the center out. dspot=(1.27*.650*f)/D dspot=(1.27*.532*f)/D dspot=(1.27*.473*f)/D We will choose 8mm as the focal length of our objective in the spatial filter. dspot=(1.27*.650*8)/D dspot=(1.27*.532*8)/D dspot=(1.27*.473*8)/D dspot=6.604/D dspot=5.405/D dspot=4.806/D In order to allow more light through we multiply a correction factor of 1.5 to the calculated values. Pinhole=9.906/D Pinhole=8.108/D Pinhole=7.209/D Now we are using only one pinhole and we need three beam diameters to make three equal spot sizes. If our red laser is 10mm then we use a 10 micron pinhole. For green the beam needs to be 8.1 mm in diameter. The blue beam needs to be 7.2 mm. Now the last equation we need is a way to change the diameter of our laser beams. In order to make a beam larger (or smaller really) we need to understand a very simple equation. InputD/OutputD=fl1/fl2 when the lenses are at fl1+fl2 distance apart. So if our red laser is 10mm dia. And our Green laser is 5mm then we need a telescope in the path of the green laser in the ratio of 5 to 8. If the lenses we have access to are 50mm and 80mm focal length then we place them 130mm apart and in the path of the green beam before the beam combiner. Now for example if the blue laser is 2.5mm we need to be 2.5 to 7.2 ratio and we could choose 25mm and 75mm focal length lenses placed 100mm apart. Now when we combine the beam we get a true Gaussian white beam. When we pass them through the spatial filter we have a white Gaussian spot with no color variation across the beam diameter. Note these same equations can be used to [[Circularize an Elliptical Laser Beam]] using cylindrical lenses. For reference: http://www.edmundoptics.com/techsupport/DisplayArticle.cfm?articleid=272 63f95f19ebac61f77fcbf44ce4400445699cbeaa 0 514 1179 1178 2013-05-12T02:54:51Z Jsfisher 1 1 revision wikitext text/x-wiki Some emulsions are harder than others. Harder emulsions can take squeegeeing better than softer ones. BB-640 and PFG-01 are pretty hard and sqeegees well; Ultimate and PFG-03 are pretty soft and easily scratched. *Squeegeeing works better when a wetting agent is used. Photoflo works well, but some think it may contribute to printout. Others use the Ilford product, or just a drop of liquid soap in the final rinse. *You didn't say if you were using plates or film. For film, use a piece of clean glass to support it. Stick the film to the glass emulsion side down a la index matching and squeegee the back. The remove the film, squeegee the glass dry, and stick the film back onto the glass emulsion side up and squeegee that side last. *For glass plates, the sharp edge of the glass will make cuts in the rubber blade, which will leave streaks next time. To minimize this problem, make a jig that keeps the wiper blade in the same position relative to the plate every time. This way the cuts will always be close to the edge of the glass. 15cee72873159d5a455057f4378ac46d1f7d9785 0 515 1181 1180 2013-05-12T02:54:52Z Jsfisher 1 1 revision wikitext text/x-wiki Stephen Benton [[Image:Benton.jpg]] In Memory: (December 1, 1941 - November 9, 2003) Allen Professor of Media Arts and Sciences Director, Center for Advanced Visual Studies Group: Spatial Imaging [http://www.media.mit.edu/~sab Benton at MIT]] Biography Stephen Benton was best known as the inventor of the white-light "rainbow" hologram, most often seen on credit cards and magazine covers. He was also known for the work he and his group did to create the world's first real-time interactive holographic video system. He was a prolific author and held multiple patents in optical physics, photography, and holography. Benton headed the Lab's Spatial Imaging research group. While an MIT undergraduate, Benton worked with Harold "Doc" Edgerton in the famous "Strobe Lab," and received his BS degree in electrical engineering in 1963. He continued his studies at Harvard University, receiving a PhD in applied physics in 1968, and remained at Harvard until 1973 as its first assistant professor of applied optics. He was associated with laboratories of the late Edwin Land at Polaroid Corporation since his undergraduate days, and returned there to establish an imaging physics laboratory, where he did much of the early work on white-light viewable holograms, and explored other applications of lasers to photography. Curriculum Vita 1999 E. Rudge ('48) and Nancy Allen Professor of Media Arts & Sciences Head, Spatial Imaging Group, Media Laboratory Director, Center for Advanced Visual Studies (CAVS) Graduate Officer, Program in Media Arts & Sciences Massachusetts Institute of Technology 1999 Vice President, Society for Imaging Science & Technology 1996 Director, Center for Advanced Visual Studies (CAVS) 1990 - 1993 Board of Governors, Int'l Soc. Optical Eng'g (SPIE) 1987 - 1994 Founding Head, MIT Program in Media Arts & Sciences 1987 - 1992 Board of Trustees, Museum of Holography, New York 1984 Founding Faculty, Media Laboratory, MIT 1982 Founder, Spatial Imaging Group, MIT 1980 - 1984 Chairman, US National Committee for the International Commission for Optics 1980 - 1983 Visiting Scientist, MIT Laser Research Center 1979 - 1984 Visiting Committee, International Museum of Photography at George Eastman House 1978 - 1981 Board of Directors, Optical Society of America 1976 - 1977 President, Optical Society of America, New England Section 1973 - 1982 Senior Scientist, Polaroid Corporation 1968 - 1973 Assistant Professor of Applied Optics, Harvard University PUBLICATIONS: Articles: 46 Patents: 14 EDUCATION: Bachelor of Science in Electrical Engineering, MIT, 1963 Master of Science in Engineering, Harvard University, 1964 Doctor of Philosophy in Applied Physics, Harvard University, 1968 PROFESSIONAL SOCIETIES Optical Society of America (Fellow, former Director) Society for Imaging Science & Technology (IS&T/SPSE) (Fellow, Vice President) Institute of Electrical & Electronic Engineers The International Society for Optical Engineering (SPIE) (Fellow, former Director) Society for Information Display (SID) Holographic Display Engineers & Artists Club (HODIC, Japan) 42cb8fb62edab870ef208aab91ebf66a925f988a 0 516 1183 1182 2013-05-12T02:54:52Z Jsfisher 1 1 revision wikitext text/x-wiki Stop baths are used in holography in the same way they're used in photography, to cease the action of the developing agent. There are several chemicals used from from running tap water, DI water to acetic acid purchased at the chemist or even vinegar purchased at the grocery store. From [1] "The use of a stop bath in ordinary photography is common, but when processing holograms certain points should be kept in mind as regards the type of hologram to the be processed. Amplitude holograms and certain types of phase holograms are also normallly fixed before bleaching. It is important to avoid contamination resulting from the use of different processing solutions, which is why careful washing between active baths is necessary. It is also important to maintain a constant temperature of all processing solutions, including all washing baths. If a develoer contains sodium carbonate (like in D-19) which when mixed with the acetic acid stop bath can cause liberation of carbon dioxide, it will result in the emulsion being perforated with a multitude of tiny bubbles." ==Photographic stop bath== ==Tap water== ==DI water bath== ==Vinegar== ==References== 1 - Silver-Halide Recording Materials - H.L. Bjelkhagen ISBN 3-540-56576-0 12756e57eef09743f092f1f3eaab3ecdb4a09c55 0 517 1185 1184 2013-05-12T02:54:52Z Jsfisher 1 1 revision wikitext text/x-wiki Staight edges, as pointed out, are to lay out straight lines and to check if things are straight and flat. Wooden materials are bad to use as staight edges as they usually have bows in them. Squares and metal rulers are good straight edges. Plastic rules are also good straight edges. A drywall square has a 4 foot straight edge with measured increments. For very long straight lines, a chalked string line (called a snap line) can be used. In expensive large straight edges can be purchased as "flat ground steel" from industrial suppliers like MSC Industrial or McMaster-Carr. Be very careful with your straight edges as they can get easily get nicks that will effect their ability to measure flatness. ==Testing a Straight Edge== If you compare any three straight edges thay can only be straight if they all match. Any two straight edges can match if they have the same curve. But, for three to match they must all be straight. 908b84de14ec2f9f306718050160d52b47145ee9 0 518 1187 1186 2013-05-12T02:54:52Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''T''' (Time) - shutter speed setting used for timed exposures longer than the numbered settings. The shutter opens when the release is pressed and closes when it is pressed again. Now largely super ceded by B (Bulb). *'''Tacking iron''' - heated tool used to stick part of the dry-mounting tissue to a print and its mounting board. *'''Tempering bath''' - large tank or deep tray filled with water maintained at the correct temperature for processing. Used to house tanks, drums or trays as well as containers of processing solutions. *'''Test strip''' - trial and error method of calculating exposure in photographic printing. A number of exposures are given to a strip of emulsion, over important areas of the image to help judge the correct exposure in the final print. *'''Texture''' - broadly defined as the surface character of an object. *'''Texture screen''' - transparent film or glass printed with a fine background pattern. They're interposed between the image and the paper to break up large areas of tone or for special effects. *'''T-Grain technology''' - name for Kodaks film emulsion technology used in all Kodak APS films. Uniquely shaped grains that align better than conventional silver crystals absorb and transmitting light more effectively to produce sharper images. *'''Thermography''' - recording images by means of the heat radiated from the subject. *'''"Thick" negative''' - antique term used to describe a dense negative. *'''"Thin" negative''' - antique term used to describe a negative lacking in density. *'''Time and temperature''' - controlling factors of a chemical photographic process. *'''Time exposure''' - general term for an exposure longer than can be set using the camera's fixed shutter speeds. *'''Time lapse photography''' - method of recording chemical and physical changes in a subject over a period of time by photographing it at regular intervals from the same viewpoint. *'''Timer''' - clock used to control processing. *'''Tinting''' - application of color tints, usually in the form of dyes or paints, to a photographic image to create or enhance color. *'''Tomography''' - radiographic technique used in medial photography. *'''Tone''' - refers to the strength of grays between white and black. It relates to the brightness, lightness and darkness of the subject and is determined by illumination. *'''Tone line process''' - technique used to reproduce a photographic image so that it resembles a pen and ink drawing. *'''Tone separation''' - process of reducing the tonal range of a photograph to a very restricted range. The final result has strong highlights and deep shadows with a set number of intermediate tones. Also refereed to as Posterization. *'''Tone values''' - various shades of gray between the extremes of black & white in a photographic image. *'''Toners''' - used to change the color of the photographic print by chemical baths. Through the system of bleaching and toning, the black metallic silver image is converted to a dye image. *'''Toning''' - method of soaking the print in selenium or similar chemical(s) to help give the print an overall feeling of "richness". *'''Transfer processes''' - methods of transferring a photographic image from one surface to another. *'''Transmission''' - passage of light through a transparent or translucent material. *'''Transmitted light''' - light which is passed through a transparent or translucent medium. The amount of light transmitted depends on the density of the medium through which it is passed and on the brightness of incident light source. Transmitted light is always less than incident light, but the amount of loss depends on the density of the medium. *'''Transparency''' - positive image in black and white or color, which is produced on transparent film. *'''Transparent magnetic layer''' - information storage layer built into Advanced Photo System film that enables enhanced information exchange capabilities. *'''Transposing frame''' - frame used for printing pairs of stereoscopic negatives from a two lens camera. *'''Tray development''' - any process carried out in open trays rather than using tanks or similar apparatus. *'''Trichrome Carbro Process''' - method of making assembly color prints from separation negatives, using an adaption of the carbro process. *'''Triple extension''' - camera system in which lens-image distance can be extended by as much as three times its focal length. It is particularly useful for close-up photography. *'''T stops''' - more accurate measurement of light entering a lens than "f" numbers. Whereas "f" numbers represent the ratio between measured diameter and focal length, "t" stops are based on actual light transmission at different diameters. *'''Tungsten filament''' - artificial light source using a tungsten filament contained within a glass envelope. *'''Tungsten halogen lamp''' - improved version of the normal tungsten lamp. It is much smaller and more consistent in color temperature as the glass envelope used is non-blackening. *'''Tungsten light''' - light from standard room lamps and ceiling fixtures, not fluorescent. *'''Two-bath development''' - development of negatives in two stages. Developer without alkali is followed by an alkali bath, which activates development. *'''Two-color photography''' - simple method of color photography which analyzes the spectrum into two parts instead of three, forming images which are combined with complementary colors. *'''Type A film''' - color film balanced to artificial light sources at a color temperature of 3400K. *'''Type B film''' - color film balanced to artificial light sources at a color temperature of 3200K. *'''Type D film''' - obsolete term for film balanced for daylight. *'''Two-bath development''' - development of negatives in two stages. Developer without alkali is followed by an alkali bath, which activates development. 70756d29a24ccd507768574266aa7c74bc4e39c5 0 519 1189 1188 2013-05-12T02:54:53Z Jsfisher 1 1 revision wikitext text/x-wiki [[Triethanolimining| Triethanolimining by Ed Wesly]] 50e4e88759deb1e7e8d36d1db812fc4e90d7bab0 0 520 1191 1190 2013-05-12T02:54:53Z Jsfisher 1 1 revision wikitext text/x-wiki ==TJ1 Developer== by Jeff Blyth '''Part A''' *6g Metol (4-methylaminophenol sulfate) *1 litre deionized water Dissolve up first then add:- 40g. Ascorbic acid (vitamin "C") '''Part B''' *100g sodium carbonate anhydrous *30g sodium hydroxide *1 litre deionized water. (This one should be labeled "very caustic" use rubber gloves and eye protection --guard against splashing at all.) Just use equal volumes of A and B with the "floating dish" method. (2 close-fitting plastic dishes are arranged so that one floats ontop of the other which contains the developer. The volume in the lower dish should be just enough to give a minimal air gap so that the uptake of oxygen is minimised and the top dish can be used as a rocker to agitate developer over a plate. Development time:- This developer is intended to react fast (to keep the silver grains spheroidal rather than filamentary, and to minimize damage to the gelatin in the strongly alkaline solution). So sufficient exposure level to give a development time of only 15-30 seconds should be aimed for . ==Notes== Developer's lifetime with the floating dish method can be days, depending on usage. A yellow or mild brown color means the developer is still good. When the developer is very dark brown or black it should be discarded. ==How this developer is thought to operate== ''The ascorbate ion with lots of alkalinity around (Na hydroxide /carbonate) is a powerful reducing agent that gets oxidized by light-damaged AgBr grains to "dehydro-ascorbate " and black or brown Ag metal grains are produced.But ascorbate ions with their negative charge are slowed from approaching the Ag+ ions in the lattice of the grain because each Ag+ is surrounded by a barrier of about 6 oppositely charged Br- ions. in the latticework, which is most often in the cubic form. (AgBr crystals can be structurally like the familiar cubic NaCl crystal , each Na+ being surrounded by 6 Cl- ions and each Cl- ion is surrounded by 6 Na+ ions ).The negative Br- ions in the lattice repel the easy access of the negative ascorbate- ions.. However “metol” is a reducing agent which is a sulfate salt and is therefore positively charged. These positive reducing ions can pass rapidly through the negative Br- lattice barricade and start reducing the Ag+ to uncharged silver metal and causing the Br- lattice ions to go into solution. But the ascorbate ions are slightly more powerful reducing agents than the metol ions so that causes newly oxidized metol ions to get returned to their original reduced form by the ascorbate ions. Therefore the metol acts as a catalyst for the ascorbate developer because it may be only momentarily oxidized.. Only when much of the ascorbate has got oxidized, do the metol ions really start to stay oxidized and oxidised metol is nearly black whereas oxidized ascorbate is merely yellow-brown. This has the useful bonus of causing the developer to get increasingly dark and this therefore acts as an indicator that it is becoming exhausted . When the developer is virtually black and opaque it means that most of the ascorbate has been oxidized and the solution should be discarded. ( Slight darkenening means the developer is OK still) . --- Another bonus about metol seems to be that it has an instant slight hardening action on soft gelatin as can be found from doing a fingernail scratch test on the notoriously soft Slavich PFG-03 emulsion after say 15 seconds immersion in “TJ1” developer made up with and without metol.'' 2cdb9145542c1d92f189d81ee9ab3881859f08aa 0 521 1193 1192 2013-05-12T02:54:53Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:NewportTable.jpg]] [http://www.newport.com Newport] Optical Table shown with a breadboard and active damped legs. ===Introduction=== Cost, size, weight, stiffness, ease of mounting component and portability are all important things to consider when designing a holography table. ===Size=== The size you choose is very important. If you make the table too small you will not have room to make more elaborate setups. If you make the table to large it wastes lab space and make it more cumbersome to align optics. You can make creative setups on small tables but for an open table layout consider the largest size of film you will use. You will need a collimation mirror capable of filling that mirror. You will also need the distance from your pinhole in your spatial filter to be the diameter of the mirror times the focal ratio of the mirror. ie. 12.5" dia mirror at f 4.5 needs to have 56.25 inches from the spatial filter to the mirror. Add some room for the mirror mount, the spatial filter objective and the steering mirror and "68 inches is about as small as you would want to make this table. It will easily allow an 8 x 10 film size. ===Flattness=== A flat table helps to allow the moving of components with out having to re-align them. Also if there are local variations in height components can rock. It is important to watch metal tables for small surface damage caused by droping sharp objects. This can allow a component to rock. ===Stiffness=== A table for holography needs to be stiff enough so when moving components around the bench you don't change the alignment of the other optical tables. Also, stiffness helps in making the amplitude of any resonances smaller and higher in frequency. This equation from LEOT has proven quite useful in table design. [[Image:TableStiffnessEq.gif]] *P = Force exerted by the point load (in lbs) *L = Length of the panel (in ft) *b = Width of the panel (in ft) *H = Thickness of the pane (in ft) *T = Thickness of the skins (in ft) *E = Young’s modulus for the skin material (in lb/ft^2) *G = Shear modulus for the core (in lb/ft^2) With these units, the deflection will come out in ft. Of course you can change units if you keep your units consistant. A proven rule of thumb is to allow 10 wavelengths of light deflection in a lab and 20 wavelengths of light deflection for art holography when adding a 100lb point load to the center of a table. '''Young's Modulus (lb/ft^2)''' *Steel 4,180,000,000 *Aluminum *Granite 1,296,000,000 *Concrete 576,000,000 '''Shear Modulus (lb/ft^2)''' *Honeycomb 32,400,000 (varies with product) *Blue Foam 96,336 *Balsa Wood 2,001,600 (varies in each tree) *Duocell 633,600 *Steel *Aluminum *Soda Cans 230,000 (best guess) ===Attachments=== Since the table is there to hold your optics stable and in position the attachment of you optics should be considered early on in table design. ====Gravity Bases==== The simplest and cheapest method for attaching optical components is to make them heavy. Filling a base with sand, lead or other heavy substance can filled into a base. A base can also be fabricated from a heavy material such as steel or concrete. ====Magnetic Bases==== Magnetic bases require the surface of the table to be ferrous. They are cheap and can be positioned anywhere. The disadvantage is the cheaper bases have a 8mm x 1 thread and the commonly available posts have a 1/4"x20tpi thread. This can be solved by machining an adapter. The bases have a rotating knob to allow the magnetic field to be turned on and off. ====Breadboard==== Tapping the table survace allows very rigid mounting of optics. 1/4" x 20 TPI Holes on 1" centers make attaching 2" diameter rods quite easy. The disadvantage is the cost of drilling and tapping all of the holes. ===Isolation=== this needs revision The ground is always in motion. It is important to keep the motion from the ground from moving the relative positions of your optics. One form of isolation it to geographically isolated from ground noise. Working on the concrete floor in a quiet location has proven to be a good choice for holographers. Another form of isolation is to rest the table on an air spring. A partially inflated inner tube has proven to be a usable choice. Sorbothane works well down to 20hz if properly loaded but below that it is not very effective. When money is no object there are commercially designed legs to isolate tables. They come in both passive and active varieties. When designing an isolation system it is important to consider the resonant frequency of the table. A low frequency resonance is more difficult to damp out, but very large and stiff table often have very low resonant frequencies. ===Resonance=== ===Table Materials=== There are a large number of materials that can be used as a table. Tables have been built from materials as different as cans, doors and pavers as well as many other commonly found items. Below is a list of commonly used materials. The suggested sizes are tables proven to work for making holograms. ====Granite==== [[Image:GraniteTable.jpg]] Granite Optical Table from [http://www.kineticsystems.com Kinetic Systems] Suggested Size: 4'x8'x12" Advantages: *Easily obtained in large sizes *Can be ground quite flat *Very stiff in larger thickness *Low thermal expansion coefficient Disadvantages: *Not magnetic *Quite heavy *Expensive ====Composite==== Suggested Size: 4'x8'x12" Advantages: *Lighter than Granite. *Has high dampening coefficient. Resonant energy is dissipated quickly. Disadvantages: *Not as stiff as granite. *Complicated to manufacture *Raw materials are difficult to acquire for amateurs. ====Concrete==== Suggested Size for art holography: 4'x8'x6" or 3'x5'x3.5" Advantages: *Inexpensive *Can easily be made flat by an experienced craftsman *Can be made in any size Disadvantages: *Not as stiff as granite per pound. *Heavy. ====Sand==== Suggested sizes: 4'x4'x12" built on plywood resting directly on the ground with inner tubes. 4'x8'x2' built on a 4'x8'x3.5" concrete base resting on 6 inner tubes. Advantages: *More Portable. *Highest Dampening coefficient. *Optic mounts are quick and easy to make. *Very flexible to design setups with. *Inexpensive. *Easily scalable. Disadvantages: *No stiffness. *Special sand is required to keep the dust low. 5c6132db581078e952c8120361716c8c119a3322 0 522 1195 1194 2013-05-12T02:54:54Z Jsfisher 1 1 revision wikitext text/x-wiki ==Setting up a table saw== *Set the blade to full depth. *Measure the blade to table angle with a square. *Adjust the blade angle to square. *Set the blade depth. If making a through cut you want the blade to not be higher than 1 tooth above the work. *Adjust the fence to position. Very carefully measure from the edge of a front tooth to the fence and then measure the tooth on the back edge the blade the fence. Adjust the fence until they are equal and the fence is square. *Setup the miter carage ==Choosing the proper blade== ==Cutting Aluminum== ==Cross cutting== ===Cross Cutting with a Fence=== ==Safety== 735609e86c695544ae6fcbb42d5febc20e22eab8 1 523 1197 1196 2013-05-12T02:54:54Z Jsfisher 1 1 revision wikitext text/x-wiki #redirect [[Talk:Holography Transmission Equations]] 826f9d5598eb8b1624a085200073cce898cd886c 1 524 1199 1198 2013-05-12T02:54:54Z Jsfisher 1 1 revision wikitext text/x-wiki I wonder if you should preface this with a basic sentence or two of what Brewster's Angle is? Personally, I thought it was the incedence angle where total internal reflection occurs. Like being under water and looking at a slight angle at the (calm) water/air boundry and getting a nice mirror effect. Or how light in a fiber optic can travel so far bouncing so many times off the internal boundries. In general, nice technical information on the wiki in, btw. I'm learning so much more now just going through the pages! -Phil ---- Does that make more sense? I also added a link to Snell's Law at the bottom to cover total internal reflection. ---- Yeah. Wow, an incredible amount of work going on Colin. -Phil 064a339cd0452d4a64476ee7875b273a780454de 1 525 1201 1200 2013-05-12T02:54:54Z Jsfisher 1 1 revision wikitext text/x-wiki Hope you don't mind, I made some changes. JohnFP Nice Work! Colin 876fd9380f0544d2b80de25577d7bd9c7e96167e 1 526 1203 1202 2013-05-12T02:54:55Z Jsfisher 1 1 revision wikitext text/x-wiki Moved un-answered questions here for further discussion. ''' Q. In this thread there was some discussion about using Sodium Dichromate instead of Potassium Dichromate and increasing the amounts of that and Glycerine to increase photosensitivity. Has anyone had good results with this? http://www.holographyforum.org/phpBB2/viewtopic.php?p=39965 ''' Q. What have people done about condensation on the cold plate? Keep it in a container with dessicant while it's not being used? ''' Q. Any chemists out there have any suggestions for a "preservative" to limit the glycerin dark reaction? ''Why do we want to limit it? It is the dark reaction additive that gives the G307 its increased sensitivity.'' Because it limits the storage time of prepared plates. If we could stop this reaction until it's desired, more plates could be made ahead of time, which would result in having more available of a known quality. d5888601fd4b974d9d58aee0275b1114015456e9 1 527 1205 1204 2013-05-12T02:54:55Z Jsfisher 1 1 revision wikitext text/x-wiki If anyone has used gelatin to fabricate a Silver Halide Emulsion, please include in this article the bloom and Type gelatin used if it was sucessful. JohnFP. feafd7de078bebeb4f1bfad90517cb4b17c23b1c 1 528 1207 1206 2013-05-12T02:54:55Z Jsfisher 1 1 revision wikitext text/x-wiki At what point does one become a "professional" holographer? Anyone have any opinions on when someone should be listed in the pro vs amateur category? ------------------------ I think in the Olympics one is no longer an amateur when they have made money practicing that sport. So I am not sure but I assume it would be, once you sell a hologram your are a professional. JohnFP 59f86cb90350bc356487b7ff363b84e7ff8982c7 1 529 1209 1208 2013-05-12T02:54:56Z Jsfisher 1 1 revision wikitext text/x-wiki Wow, this page is getting long. I think we'll need to split it out soon into seperate pages. I'm also getting conflicts as I'm editing while somebody else is too. Great work! -Phil ---- Yes, we need to cut it up. I think we can make all of the main sections into new pages. I was editing right ahead of you. I'll watch and work on different sections until I find a better way. Have you been looking at the recent changes page? It allows you to see who has been working where. - Colin ---- Hi Colin. Yes, I've been looking at the recent pages more now. This is great stuff here in the wiki. Finally things that can be contributed that aren't slipping off the bottom of the page. The good stuff gets accumulated instead of diluted and forgotten! -Phil ---- I see that recording materials is it's own set of pages. It seems like it should be part of the Technology heirarchy in the same style as however this information ends up after being diced up. -Phil ---- This is great. I took a first step and someone took it to the next level. I LIKE IT! Great work! JFP ddb853c288db0287b6d32257abf86d1335d6db06 1 530 1211 1210 2013-05-12T02:54:56Z Jsfisher 1 1 revision wikitext text/x-wiki #redirect [[Talk:Holography Transmission Equations Part I]] a29f0012f3a5f91906060add6a7f197dc97c703a 1 531 1213 1212 2013-05-12T02:54:56Z Jsfisher 1 1 revision wikitext text/x-wiki Ed- This is very nice! Can we move the TEA discussion to the Wiki? Give me te permission and I will make the changes. This sentence might need to be revised a little: "Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle!" Perhaps this is more clear: "Starting in the green means you have to post-swell to get red, (another, different, kind of headache!) the farther the shifted frequency is from the recording frequency the lower the deffraction efficience is and the dimmer the resulting hologram becomes at the same angle!" In order to upload your picture Click on the little image icon above the editing pane and it will insoert an example link. Edit it to a good name for you file. It does not have to be the same name as your original file. When you save the page and read it, click on th elink and it will prompt you to upload the file. Try to make it less than 50K so it will load quickly. Playing with morier patterns helped me a lot. Perhaps I can make a Java Applet to insert into your article. I'll work on it. Colin Ed, Sweeeeeet! JohnFP 01ab656eb2bbca37a7d97907529460d19d7e0b1a 1 532 1215 1214 2013-05-12T02:54:57Z Jsfisher 1 1 revision wikitext text/x-wiki I am not sure where to put this but one of the things that I think always presents confusion for beginning holographers is which way to orient the geometry of and H1 (overhead lighting, below lighting etc.) so that the final H2 hologram has overhead lighting with the virtual view. Where would this best be placed and what should it be called? JohnFP. ---- Put that into Holopraphy Technology:H1 to H2 Copies. I messed that one up at PCG I. 8) I will eventually get to diagram all of the set ups for that section in my CAD program. - Colin ---- This page has turned into a nice Beginner FAQ. I wonder if the page title should be adjusted to match? - Phil Edit: Oops, I see the main page already calls it a FAQ. That's probably fine. ---- I think we shold rename it to have FAQ in the title. It will help with search engines. 08a3381cef605b5140ae5dae5ceee30a9b95a2a3 1 533 1217 1216 2013-05-12T02:54:57Z Jsfisher 1 1 revision wikitext text/x-wiki I have a suggestion for the illustration. It looks like the object on the left is something between two mirrors and the two mirrors are movable in and out. I assume, but I may be wrong, that it is a resonator??? I think if it is just a laser, remove the two mirrors and the double arrow. If it is something else I am misinterpreting, maybe a small blurb below the image may help. In a Michelson, usually only one leg would want to be moved in an out...NO? JohnFP ---- I uploaded a temporary one. I'll make a better one later. ---- ffb4b5b7fb51634de4abda93fc5f32d185fabcc8 1 534 1219 1218 2013-05-12T02:54:57Z Jsfisher 1 1 revision wikitext text/x-wiki I cannot find exact numbers right now and you may have the information at your finger tips but for the yag lasers it is important to include the Near infrared (1.06 microns) wavelength in your reflectivity numbers for cavity materials. The IR pulsed lasers we used always had a gold (polished or plated not sure) cavity interior. It is after the population inversion and subsiquently the lasing the that beam is frequency doubled into the visible wavelength range. John ------------------------- Actually you don't want any reflection at 1064nm as it tends to depopulate the upper energy levels by stimulated emission in directions that are not in line with the mirrors. -Colin ----------------------- Got it. That makes sense. 18b9923bc0859d67bec980c26fed8e3d8cad85e2 1 535 1221 1220 2013-05-12T02:54:57Z Jsfisher 1 1 revision wikitext text/x-wiki I'm inspired by the work being done here. Thank you Colin for putting up such a great wiki system! That said, the main page is a little weak right now. Especially after Technology gets broken out, this page should be a little less than line-items down a page. Perhaps groupings and more utilization of the unused real estate of the page. See my toyings on the [[sandbox]] page for some style examples which control layout (experiements to see how much I could control on a page). -Phil ------ Phil, All of the changes you have made on other pages have made things look better and made it more clear and easier to read. I trust your judgment. Please feel free to edit, move, split or rename pages at will, remember if we get somewhere we don't like we can revert. Colin ---- OK, thanks. I wasn't sure where the line was drawn for major changes/moves. I'll start digging a little deeper. -Phil ---- I will try to keep the '''''Recent changes''''' to a minimum but I was playing with changes to an existing format and wanted to embed images and do it on a linked page. JohnFP ---- What does the bold '''m''' and '''N''' stand for on the Recent changes page? JohnFP ---- '''m''' is a minor edit, meaning you checked the box. '''N''' is a new page or file addition. Don't worry about the amount of recent changes. :-) ---- OK, I put up a new main page. I'm not stuck on it, so rip it apart or whatever, it won't hurt my ego. ;') Keep in mind, that the styles define where (physically on the page) the links and text are. So, moving them into a different order does nothing. You have to tweak pixel offsets if you want BTW- The image was created using my red diode, DPSS green, and DPSS blue lasers... ha! yeah right. It's really from three seperate photos, all done with the same ancient HeNe laser. Each was turned into grayscale and colorized R,G, & B (I tried to eyeball reasonable laser colors). When layered together, the lightbulb became a very convincing white all by its self. I basicly blurred the crap out of the background, foreground, and bulb, removed 'stuck' pixels from my crappy dig camera, and added a slight embelishment from the reflected rays off the lightbulb. But, those highlights on the counter are untouched. -Phil ---- Ah, another important note is: I tried to order the topic for newbies (obviously) to the upper left, and then informational links down the left. Users in unfamiliar web pages tend to start upper left and work down. Hard core technical info goes down the right side (i.e. stuff for people who MAKE holograms). People looking for info browse the left, producers of holograms the right. It helps keep the people hitting the page for the first time in an area that they are likely to be most interested in. And, users who are familiar shouldn't have any problem looking to the right for the links they want. -Phil ---- I like the new page. I made it a little smaller to fit in one screen view for most monitors. I don't know haw to change the link colors on one page only. I know how to set them for the whole wiki. I am afraid the the blue visited link is too dark. ---- Phil that is great and amazing. I like it. John ---- I don't like the darkened image, but I total agree that the links aren't bright enough. Hummm. Overriding that style w/i the wiki is a bit of a problem. I'll ponder and play some more. Another random thought is that the 'main' page could be a static page outside of the wiki, but that might be a bit premature since things are still in major flux. At some point the main page might benefit from the added customization and control of being static. TTYL, and have a good weekend, guys! -Phil ---- I did not delete some of the older revisions of the file, I just renamed them. Play with the brighter ones. If you find one that the writing is not overwhelmed by the light bulb I am cool with having a brighter image. I like how the lasers bounce throough the lightbuld and illuminate spots on the table. ---- I am trying to change the links to a bright green for this page only. I don't quite understand this article: [http://meta.wikimedia.org/wiki/User_styles#CSS_selectors] Can we do it with this? Colin ---- I don't quite understand that page either. Can you include a css style sheet just for the main page? If so, then I think we can just create a style for bodyContent.a {color:green} (Or something like that) -Phil ---- OK, take a look at my personal page for a possible work around: http://www.holographyforum.org/HoloWiki/index.php/User:Phil_Edelbrock -Phil ---- I like that solution. Good Idea! I would prefer the words to be 532nm green. Then we could brighten up the image again. The old image was tough to view on LCD monitors as it was a little overwhelming. Colin ---- I assume you've got photoshop, right? I'll attach the PSD here. I started with a light green color, but Lippman got hard to read with the lighter image. BTW- Lippman Photography seems to be a rather odd topic to throw on the main page. It seems like it should belong to another broader category like under Technology? (edit: oops, I can't upload the file here. I emailed it to you Colin.) -Phil ---- Tweaked home page after chatting w/ Colin. Centered the light bulb (I wish it were straighter). I swapped Recording Tech and Technology, too, so they were more readable. Please email me if you want the photoshop file (phil (at) philedelbrock.com) -Phil ---- I moved the "obtaining Login" information to the footer. I also moved the What is a wiki to the about article. I then changed the page naming so it adds "A Holography Database". I think this will help us target the search engines better. ---- I reduced some wordiness on the bylines to one-liners. I think it looks and reads a bit better, but feel free to edit/revert. -Phil ---- I like the look and feel of the one liners. I would like so text for the google bots to find. Now that the text is in the image there is very little for gogle to search. Do you have any ideas? -Colin ---- Here are the original descriptions I chose them to be searchable. Perhaps we can imbed the text invisably into the main page? Welcome to the [http://www.holographyforum.org Holography Forum's] Holography Wiki. The goal of this wiki is to create a knowledge base for the holographic arts. It is divided into sections as follows: *'''[[Holography for Beginners]].''' A FAQ for beginning holographers. *'''[[Holography Technology]].''' The hardware and setups for making holograms. *'''[[Hologram Recording Materials]].''' *'''[[Holography Theory]].''' The Mathematics of Holography. *'''[[History of Holography]].''' A project to document the people and events before we grow old and forget how exciting this last 60 years has been. *'''[[Holography Safety]].''' Knowledge and practices. *'''[[Biographies of Holographers]].''' The people who have made the magical world of holography posible. *'''[[Holography Links]].''' The World Wide Web for Holography. *'''[[Holography Glossary]].''' A Glossary of holography releated terms. ---- Ok, that still needs lots of work, but I have to run to work. ---- Yeah, they could just be under the image. Google will see them and others won't. (edit: lol, I was thinking under the image literally as a style layer underneith, but a text summary at the bottom of the page works great, too. Probably better since we can see and edit it.) -Phil ---- I revised the footer nav. Colin, if you have the psd file that made the current image handy, center up the light bulb (say 10 pixels to the left, from eyeballing it). That will help make Lippmann a little easier to read and center up the image. This is really great stuff on the wiki. I'm glad to be a part of it, I just wish I had more time/money to help. ;') -Phil ---- I made a new logo for the holography forum link in the footer. It is much sharper. I tried to move the bulb around but I am not skilled enough. I was creating problems on the right edge and then I was loosing some of the laser light bouncing down from the bulb under some of the words. :-( -Colin Feel free to clean up the Hologram Recording Materials section on the main page. I tried to add (& Chemistry) which is in the code but could not get it to show up on the Main Page. So I modified the description underneath. I believe we need this as it is hard to find where chemistry is discussed on the main page. JohnFP Never mind. I found that what I tried to alter in the titles ended up breaking the links, so I just added to the discription of each on the main page to include chemistry. JohnFP --------------------------------------------------------------------------------- Do you think we should have a "Suppliers" section? I was thinking of purchasing some of those magnetic mount bases and could not find the thread on the forum. I know as time goes on it may become outdated but it would be a good reference for things like Pinholes, bases, chemicals etc.. John Pecora --------------------------------------------------------------------------------------------- I wonder if we want a manuals section. I have found that to be the hardest thing to locate when a used piece of equipment is purchased. Augie sent me a copy of his for my Ion laser. And I was reading a laser forum and someone else was looking for that same manual, whick I will copy for him. Are their any legalities associated with posting manuals here? John Pecora --------------------------------------------- If we have a disclaimer that we contacted (a person's name) and recieved permission to publish it here. This is not the easiest thing to aquire. Without it I would advise you to make a section on your own site and post a link in the links section. Oh, yeah the supplier for magnetic baes is Enco. 777c155f556a59c7336d16bb773b3939414a234e 1 536 1223 1222 2013-05-12T02:54:58Z Jsfisher 1 1 revision wikitext text/x-wiki I am not sure but I believe the Rain-X was used just on the surface of one of the pieces of glass to allow the emulsion not to stick to that piece of glass. I believe if you treaded both peices of glass the emulsion may lift off the piece of glass it was meant to stick to. ---- Rain-X will not stick to gelatin at all. I believe it is silicone. It is important to only coat one side. 7a448fa172449b02902444e0a451e93f75a674f9 1 537 1225 1224 2013-05-12T02:54:58Z Jsfisher 1 1 revision wikitext text/x-wiki Colin, I don't know how to delete and uploaded file. So I had to re-upload this one and named it "PreScoredCoatAtOnce2.JPG". Could you delete the original named [[Image:PreScoredCoatAtOnce.JPG]] and explain how to delete an uploaded file. I do not want to waste space on the server. John P. ---- Hi John, if you have the image showing, click on the image. There is a button for deleting it. I don't really know why we can save a new image to an old name, it is not a reported bug with this version. It likely has to do with the security settings... BTW, nice work! I deleted it... 289dd642d3cb24ccb32f7bfbfc056273103f3c03 1 538 1227 1226 2013-05-12T02:54:58Z Jsfisher 1 1 revision wikitext text/x-wiki I am not sure why you had the first measurements of the red and blue beams at 4 instead of 4.5 thus indicating different path lengths compared to green. I matched them to the diagram (4.5) and all paths are the same length again. Thanks for taking the time to review it though. ---- It did not really bother me as in the real world sometimes you have to accept a beam placement that will fit on the table and not really the best beam. Thanks for the work! 7eaf94811f8f6d1dc385b824423ed3bd689e34fe 1 539 1229 1228 2013-05-12T02:54:58Z Jsfisher 1 1 revision wikitext text/x-wiki I might suggest that on smaller scales, the distiller option might be cheaper and provide a better solution to, say, charcoal filtering? For example, I bought my 1-gallon distiller (on super-sale) for about the cost of 3 Pur charcoal filters. Granted, the power usage of the distiller is an additional cost, but I wouldn't think it was significant? Of course, $50 or $100 can buy a lot of distilled water at the local mega-mart, too! 3da4b9475901b88f33ed8540f3a895b0ca39909c 1 540 1231 1230 2013-05-12T02:54:59Z Jsfisher 1 1 revision wikitext text/x-wiki How does one delete an entry? This article needs to go away. 3a43db2cbf91d2d636a749f4021ab62ce2a49225 1 541 1233 1232 2013-05-12T02:54:59Z Jsfisher 1 1 revision wikitext text/x-wiki I like the beginning you have. The blue writing for the links is a little difficult however. Nice Image. a259d7830c1cad37e34dffd5976d58103c37ff43 1 542 1235 1234 2013-05-12T02:54:59Z Jsfisher 1 1 revision wikitext text/x-wiki I am sorry, I could not for the life of me find where "Path Length Matching" was linked so I included it here. Feel free to move it to a more appropriate location if you find it more helpful. JohnFP ---- The cool thing about the wiki is you can link from anywhere and everywhere! ---- a499200e3a33959dba2909745df31c05c1d39428 1 543 1237 1236 2013-05-12T02:54:59Z Jsfisher 1 1 revision wikitext text/x-wiki Hi John, I was wondering if this should all be on this page? It would be easier to compare the differences and learn if they were all on one page. Colin ---- Feel free to reorg as you wish. John ---- How is that? C 7d7d6229aabbc1d7886d45f73aacb6c0f2c51bb7 1 544 1239 1238 2013-05-12T02:54:59Z Jsfisher 1 1 revision wikitext text/x-wiki This should probably be included on the links page. [[Holography_Links#Links_to_Holography_Supplies_and_Tools]] ---- Ok, should I reorg the section in this link by item, then put the suppliers underneath? That way one that is looking for a "front surface mirror' for example can find it more easily. John ---- That is a good idea. Also the descriptions are very brief now. Perhaps we will have time to expand them... 8211e6ccb402748a9056794fea357704d62530a2 1 545 1241 1240 2013-05-12T02:55:00Z Jsfisher 1 1 revision wikitext text/x-wiki Thank you Colin for the formatting. I have a few images that I would like to upload but cannot. Here is the error I am getting;" The upload directory (/var/www/vhosts/holographyforum.org/httpdocs/HoloWiki/images) is not writable by the webserver." The images are in the reference (16). The first three images. The first two I would like in the collagen section. And the third in the Gelatin section. I wonder if you could upload the images or possibly investigate why I cannot upload the files. Thank you, John ---- Try that. Colin. ---- Thank you, works fine now! a638bd1dcd7da65082f784cbeb941653051198d6 1 546 1243 1242 2013-05-12T02:55:00Z Jsfisher 1 1 revision wikitext text/x-wiki Colin, your amazing and this Wiki is great. I was reading over the HeNe section this statement is contained, "If the mirrors are placed at Brewster's Angle then the laser will have a Polarized output. Some HeNe lasers have mirrors that are external to the glass tube and some have mirrors bonded into the glass tube." I am not sure how the mirrors can be placed at brewsters in an in line cavity. But I didn't want to change is as I surely could be lacking in understanding here. Also, I have taken pictures of my SP Argon Ion and will be uploading them soon. I will let you link them where you think best or tell me and I will do it. I assume in this section would be one good place to link them. Also, with these discussions, would it be advantageous to delete the discussions after they are outdated or leave them? John --------------------------------------- No you are right it should be Brewster's windows with external mirrors. Your understanding is exactly correct. For now leaving the discussions helps people to realize what the pages are for so I have been leaving them. Colin PS Have you seen the MOPA page? It is comming along. I'll announce it when it is further along. --------------------------- Yes I have seen it. Your doing an amazing job. I am grateful for your unending enthusiasm for the WIKI. John ---------------------- Colin, I don't seem to be able to see the photos of the Argon Ion laser I uploaded. I could see them the day I uploaded them but not for the laser week or so. Is it on my end or on the Wiki end? John ----------------------- This is aproblem on my end. I can't seem to find the setting for the Max image size. I think it is set to around 50K. When I have had problems like thi I make the picture files smaller. I looked for a good 40 minutes for the setting but I cna't find it. I'll keep working on it. ---------------------------- If it's easier, you can just make the files smaller so that they are displayed. John --------------------------------- 9c84899608364fe3ebcc303f35129c2ee231fce7 1 547 1245 1244 2013-05-12T02:55:00Z Jsfisher 1 1 revision wikitext text/x-wiki This isn't really DCG specific is it? Well, I guess maybe it could be modified for gelatin only but I seem to realise that the Silver method that uses gelatin is at a much higher concentration and thus thicker and may prove to be diferent. I figured to keep it as knowledgable and first hand as possible I would post it as DCG and others could add another section for plain gelatin. What do you think? 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padding:1px 07257e0b5b8376ea25e1fd0b6804965eb6a947d7 10 567 1285 1284 2013-05-12T02:55:06Z Jsfisher 1 1 revision wikitext text/x-wiki {| style="clear: both; width: 75%" align="center" class="toccolours noprint" !align="center" style="background:#ccccff"| [[Periodic table]]s |- |align="center"|<small> [[Periodic table (standard)|Standard table]] | [[Periodic table (alternate)|Vertical table]] | [[Periodic table (big)|Table with names]] | [[Periodic table (large version)|Names and atomic masses (large)]] | [[Periodic table (detailed)|Names and atomic masses (small)]] | [[Periodic table (text only)|Names and atomic masses (text only)]] | [[Periodic table (wide)|Inline F-block]] | [[Periodic table (extended)|Elements to 218]] | [[Periodic table (electron configurations)|Electron configurations]] | [[Periodic table (metals and non-metals)|Metals and non metals]] | [[Periodic table (block)|Table by blocks]] </small> |- !align="center" style="background:#ccccff"| Lists of elements |- |align="center"|<small> [[List of elements by name|Name]] | [[List of elements by symbol|Atomic symbol]] | [[List of elements by atomic number|Atomic number]] | [[List of elements by boiling point|Boiling point]] | [[List of elements by melting point|Melting point]] | [[List of elements by density|Density]] | [[List of elements by atomic mass| Atomic mass]] </small> |- |align="center" style="background:#ccccff"|[[Periodic table group|'''Groups:''']] &nbsp;&nbsp;[[alkali metal|1]] - &nbsp;[[alkaline earth metal|2]] - &nbsp;[[Group 3 element|3]] - &nbsp;[[Group 4 element|4]] - &nbsp;[[Group 5 element|5]] - &nbsp;[[Group 6 element|6]] - &nbsp;[[Group 7 element|7]] - &nbsp;[[Group 8 element|8]] - &nbsp;[[Group 9 element|9]] - [[Group 10 element|10]] - [[Group 11 element|11]] - [[Group 12 element|12]] - [[Boron group|13]] - [[carbon group|14]] - [[nitrogen group|15]] - [[chalcogen|16]] - [[halogen|17]] - [[noble gas|18]] |- |align="center" style="background:#ccccff"|[[Periodic table period|'''Periods:''']] &nbsp;[[Period 1 element|1]]&nbsp; - &nbsp;[[Period 2 element|2]]&nbsp; - &nbsp;[[Period 3 element|3]]&nbsp; - &nbsp;[[Period 4 element|4]]&nbsp; - &nbsp;[[Period 5 element|5]]&nbsp; - &nbsp;[[Period 6 element|6]]&nbsp; - &nbsp;[[Period 7 element|7]]&nbsp; - &nbsp;[[Period 8 element|8]]&nbsp; - &nbsp;[[Period 9 element|9]] |- |align="center" style="background:#ccccff"|[[Chemical series|'''Series:''']] &nbsp; [[Alkali metal|Alkalis]]&nbsp; - &nbsp;[[Alkaline earth metal|Alkaline earths]]&nbsp; - &nbsp;[[Lanthanide]]s&nbsp; - &nbsp;[[Actinide]]s&nbsp; - &nbsp;[[Transition metal]]s&nbsp; - &nbsp;[[Poor metal]]s&nbsp; - &nbsp;[[Metalloid]]s&nbsp; - &nbsp;[[Nonmetal]]s&nbsp; - &nbsp;[[Halogen]]s&nbsp; - &nbsp;[[Noble gas]]es |- |align="center" style="background:#ccccff"|[[Periodic table block|'''Blocks:''']]&nbsp; [[s-block]]&nbsp; - &nbsp;[[p-block]]&nbsp; - &nbsp;[[d-block]]&nbsp; - &nbsp;[[f-block]]&nbsp; - &nbsp;[[g-block]] |} [[Category:Periodic table]] 444432fbf1179260ba9c5d9330be8ec05abe0014 0 568 1287 1286 2013-05-12T02:55:06Z Jsfisher 1 1 revision wikitext text/x-wiki ==A Simplified Analysis of Holography== Assume a photographic plate in the xy plane: Given a reference beam: [[Image:HoloEQ1.gif]] where [[Image:HoloEQ2.gif]] is the amplitude as a complex number retaining the phase information. The reflected object beam is: [[Image:HoloEQ3.gif]] At the plate the fringe amplitude is given by: [[Image:HoloEQ4.gif]] because the square of the magnitude of a complex number is product with its complex conjugate. (Note: [[Image:PhotographyEQ1.gif]] is the amplitude of a photograph. See how we lose the imaginary part of the equation, this is when we lose the phase.) Thus, [[Image:HoloEQ5.gif]] The first and second terms are intensities of the reference and object beams. The third and forth terms are the magnitude and phase of [[Image:HoloEQ6.gif]]. When we reconstruct the hologram, [[Image:HoloEQ7.gif]], with the reference beam [[Image:HoloEQ8.gif]], so that the transmitted light has the complex magnitude [[Image:HoloEQ9.gif]], [[Image:HoloEQ11.gif]] i.e. [[Image:HoloEQ12.gif]] or [[Image:HoloEQ13.gif]] where [[Image:HoloEQ14.gif]] and is the zero order beam (it passes straight through the hologram). [[Image:HoloEQ15.gif]] is the intensity of the reference beam and [[Image:HoloEQ16.gif]] is the virtual image. The third term, [[Image:HoloEQ17.gif]], is the real image. It is important to notice that its amplitude is the complex conjugate of [[Image:HoloEQ18.gif]]. (We have to flip the plate to make the conjugate or real image.) 245c9c8cc96f8269731a513fc2efb3c8af9b1bcf 0 569 1289 1288 2013-05-12T02:55:07Z Jsfisher 1 1 revision wikitext text/x-wiki ==The Eye== from LBL [[Image:TheEye.gif]] A diagram of the human eye. The eye is the area of greatest concern with respect to laser safety.The various parts of the eye are described below, along with descriptions of how laser radiation can harm them. ===Cornea=== The cornea is a transparent living membrane that covers the eye. It is very thin and composed of epithelial cells over a supporting matrix. The cornea has no blood supply; thus, its cells have no defense system and are easily damaged, both thermally and mechanically. If corneal injury is minor, then regrowth of epithelium can occur within a day or so without any permanent abnormality. If more extensive injury occurs, corneal scarring may ensue, with loss of the capacity of the cornea to conduct clear images. Damage to the outer cornea ranges from uncomfortable to painful, but will usually heal in one to two days. Damage to the cornea and the conjunctiva tissue surrounding the eye usually occurs at greater power levels than damage to the retina; therefore, these issues only become a concern for those wavelengths that do not penetrate to the retina (UV and IR radiation). Since amplification by the lens is not involved, injuries can also be caused by diffuse and noncoherent light. ===Lens=== The lens focuses light to form images on the retina. The lens does not have an active cellular turnover and thus cannot repair itself. Over the course of repeated minor injury, or even one major injury, the lens may become progressively more opaque. This condition is known as cataract formation. While cataracts are a common side affect of aging, they are accelerated by exposure to certain light energies, including lasers. When UV or IR laser light enters the eye, much of the light is absorbed in the lens. Depending on the level of exposure, this may cause immediate thermal burns or the development of cataracts over a period of years. ===Retina=== The retina is made up of a thin layer of light-sensitive cells called rods and cones, so named for their basic appearance. The rods make up the vast majority of the retina (over 95% of the total retinal area) and are sensitive to both movement and light and dark. They are more sensitive to light than are the cones, but they cannot see color. The cones make up less than 5% of the total retinal area, but that area is the critical central part of the retina, called the fovea centralis, where we see both color and fine detail. The retina is an actual extension of the human brain. Retinal cells detect only what we call "visible light." Laser light in the visible and near-infrared (IR) region (400–1,400 nm) that enters the eye is focused on the retina, creating a hazardous concentration of laser energy out of a "minor" laser source. One mW of visible laser radiation entering the eye deposits 100 W/cm2 at the retina. b9a5ad7681877eca7f3ff3f03f2f4ae03282a117 0 570 1291 1290 2013-05-12T02:55:07Z Jsfisher 1 1 revision wikitext text/x-wiki ===Dust Hoods=== Keeping your work area dust free is a prime consideration when making your own emulsions. HEPA work stations are commercially available but are expensive. A home made work station can be easily made. [[Image:LaminarDetail.jpg]] John Peccora built this nice bench top Dust hood for DCG plate coating. On the left is the front view and on the right is a side cross section. For the back wall he used a plastic material that looks like square tubes with a screen covering. [[Image:CommercialLaminar.jpg]] This is a Commercial HEPA work station made by [http://www.nuaire.com/ NuAire]. It has pre-filters on the bottom with a squirel cage blower and the entire back of the work area is one large HEPA filter (4' x 3'). There are four 4' flourescent bulbs in the top. In order to make sure there are no air vortexes that can trap dust it is important to have the air flow over the entire bench in a laminar fasion. In order to insure a laminar flow the air needs to be directed through a parallel series of tubes. A bunch of straws work perfectly. In order to test the flow one can take a candle and put the flame in different places in the work area. Places where the flame flickers have turbulence and are unacceptable. ===Fume Extraction=== Processing with formaldehyde and alcohols are common in processing holograms. The fumes are dangerous and provisions should be made for venting them saftly outside. A simple bathroom fan is insufficient. Commercial suppliers like [http://www.mcmaster.com McMaster Carr] and [http://www.mscindustrial.com MSC Industrial] have explosion proof fan assemblies in the $500 range. A good rule of thumb is to have enough venting to exchange the complete air in your room 30 times per hour. Check your local regulations for more requirements. ===Processing Areas=== The processing are needs to be designed with a few considerations: *Light tight *Washable surfaces *Dust free *Running water *Lockable chemical storage *Counter space for processing trays ===Safe lights=== In order to see while you are working it is important to have some light. Fortunately if you are using film that is only sensitive to red you can make a green safelight. You should test your safelight before you use it. If you are using long settle times it is wise to make sure no safelight hits the bench during the settle period. ====Testing Safe Lights==== Do a preliminary test of reflecting the light off of a diffraction grating, CD or DVD. Shine the safe light at the grating and bounce the reflection back to your eyes. If it looks the same then you are looking at the zero order reflection, rotate the grating or CD until you see a reflection that looks like a rainbow. This is a higher order reflection. If you can see red in this reflection then your light is not safe. ====Exposure Test==== The next test is to get out a piece of your film. Find the uncoated side. Place a piece of electrical tape down one side to make a test patch that has not been exposed. Put the film about a foot from your safelight with the tape facing the light. Add one piece of tape at 15 seconds, 30 seconds, 60 seconds, 10 minutes, 30 minutes. At 60 minutes put the plate in developer. If your plate turns completely black then your safelight is not usable. If only the 60 minute or 30 minute lines develop you are probably OK. ====Safe Light Types==== '''For Red Sensitive Film''' *Lime Light: The easiest light to use is a "Limelight" night light. It is very low power and mostly green. If you add a Rosco Gel #90 available from a theatrical supply shop it will be very good but very low power. Attach the gel with electrical tape. John Klayer uses a row of gelled Limelights above his bench. *Kodak Safe Lights: Kodak makes a #7B and #3 green saflelight filters (#3 is recommended by Shoebox Holography) suitable for red sensitive holographic films. *Home Made Lights: Just using a piece of Rosco #90 (Theater Gel) over a conventional bulb is not enough. Use two layers of #90 or better to have one layer of #90 and one layer of #95. #95 lets in too much deep red to use alone and #90 lets in too much yellow that the Slavich materials are sensitive to. *MiniMag Flash Light: Use Two layers of Rosco #90 or better yet one layer of #90 and one of #95 for red sensitive film. *T40 EncapSulite fluorescent bulb covers can be used for holographic safelights. [http://www.flexopress.com/production/encapsulitelightsleeves.html EncapSulite] For general information about Safelights see: [http://www.kodak.com/global/en/consumer/products/techInfo/k4/k4Facts.shtml Kodak Safe Lights] 1e39ee67f2f384f525685676d7e63b86a502a8b7 0 571 1293 1292 2013-05-12T02:55:07Z Jsfisher 1 1 revision wikitext text/x-wiki ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and Dichromated Gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300nm long and 1.5nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape(2,3,4,5,19). If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties(6,7). These two images were taken from source (16). [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion(6,8,9). Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions(13,14). Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom(13,14). This image was taken from source (16). [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them(10,12). Research is needed using vitamin C with CrVI(11). ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII (15). During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram(15). The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://en.wikipedia.org/wiki/Collagen # http://www.britannica.com/eb/article-72553/protein # http://www.lsbu.ac.uk/water/hygel.html # http://www.stanford.edu/~spark7/ # http://en.wikipedia.org/wiki/Gelatin # http://www.lsbu.ac.uk/water/hygel.html # http://albumen.stanford.edu/library/c20/kozlov1983.html # http://www.greatlakesgelatin.com/gelatin%20information.htm # http://www.cdc.gov/niosh/topics/hexchrom/ # http://en.wikipedia.org/wiki/Hexavalent_chromium # http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/ # http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf # http://www.gelatin-gmia.com/index.htm # Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora # http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html # http://sandwalk.blogspot.com/2007/02/collagen.html d8a58ace23ab9b4c17938f8195ba69b3c28a8a22 0 572 1295 1294 2013-05-12T02:55:08Z Jsfisher 1 1 revision wikitext text/x-wiki Thermometers come in a variety of types. They are used to measure the temperature of a gas, liquid or solid. ==Liquid Filled Thermometers== [[Image:LiquidThermometer.jpg]] '''Advantages''' *Accurate *Calibration is insensitive to mechanical shock. '''Dis-Advantages''' *Fragile *Difficult to insert into processes *Can not be recalibrated ==Bi-Metal Thermometers== [[Image:BiMetalThermometer1.jpg]] [[Image:BiMetalThermometer2.jpg]] '''Advantages''' *Easy to read *Easy to insert into proceses *Easy to recalibrate '''Dis-Advantages''' *Calibration is sensitive to mechanical shock ==Thermocouples== ==IR Thermometers== [[Image:IRThermometer.jpg]] '''Advantages''' *No contact is required *In-expensive *Easily measures surface temperature of solids '''Dis-Advantages''' *Only measures surface temperature ==Thermometer Calibration== For Calibrating low temperature thermometers make a bath of distilled water and crushed ice. Stir this solution for a couple of minutes and your thermometer should read 32F or 0C. Adjust as necessary. For Hi-Temperature thermometers boil distilled water. Your altitude will effect the temperature of boiling water. At sea level adjust to 212F or 100C. At 2000 ft adjust to 208F. At 4000 ft adjust to 204F. At 6000 ft adjust to 201F. at 8000 ft adjust to 197F. at 10,000 ft adjust to 194F. ==Further Reading== http://en.wikipedia.org/wiki/Thermometer 3630a814cd27e70eff73bc2ed293b8e6bb6f4699 0 573 1297 1296 2013-05-12T02:55:08Z Jsfisher 1 1 revision wikitext text/x-wiki ===''Pinhole Calculation''=== As per Newport. D = Fw/a , where D = Pinhole Diameter F = Objective lens focal length w = Wavelength of laser (sorry no greek letter on my keyboard) a = Beam radius at input to lens More.... [http://www.newport.com/store/product.aspx?id=3873&Section=detail&lang=1# "Newport Pinhole"] ===''Calculating Laser Power vs Film Requirement vs Exposure Time w/Sample''=== Joules = Watts x seconds thus 1 mW = 1mJ/1 second 1 inch = 2.54cm 1 square inch = 6.45cm^2 For a film requiring '''100 mJ per cm^2''' Plate length(2.54 cm) x width(2.54 cm) = '''6.45 cm^2''' Laser putting out 10mw = '''10mJ per second''' '''10mJ per second''' /'''6.45cm^2''' = 1.55mJ per cm^2 per second '''100mJ per cm^2'''/1.55mJ per cm^2 per second = 64.5 seconds This is just a basic starting point based on the film energy requirement. Adjustments need to be made for laser light losses, processing etc.... ===''Detecting the Emulsion Side of the Plate''=== Most of these can be tried with a used piece of film plate with the lights on for practice. Note: These tricks rely on the fact that only one side is gelatin; with the Fuji film both sides are gelatin. If you breathe on the plate, the side that does not fog will be the emulsion side (no condensation occurs on the emulsion side because the gelatin absorbs the moisture). (This does not work for the Fuji film as it has gelatin on both sides.) Look at the edge of the glass with a safelight - the cleanest (non-ragged) edge is the emulsion side. With a bit of practice you can detect the difference in the dark by rubbing your thumbnail along the edge. If all the plates are oriented the same way, you can label the box ''emulsion this side ->'' The two finger method: moisten your thumb and index finger and pinch them together a few times. Now do the same motion with the plate between them, and it should be easy to feel which side is the sticky emulsion side. ===''Got old plates?''=== I have stacks of failed plates. Do yourself a favor now that you have some scrap plates: Spray paint one of the ruined jobbies white and use that as a dummy plate when setting up. Both sides and the edges. You will find this very useful when it comes to carding off light that would otherwise enter the edges of the glass as well as for checking the quality of your reference beam. A clean white surface is also nice for making sure that you have no specular reflections from shiny places on your object(s)... 9c1bd633db1f6db02b455471735d8373e0d05614 0 574 1299 1298 2013-05-12T02:55:08Z Jsfisher 1 1 revision wikitext text/x-wiki ====Tips for Pulsed Ruby Holograms==== by Ron Michael When using a pulsed ruby laser and to avoid the waxy look of pulsed ruby reflection holograms try these tips: A reflection hologram is taken instead of a H1/H2 setup. The person sits further back (A safety requirement of this setup to avoid the reference beam in regards to shooting a direct reflection hologram. Details: [http://www.rotorwave.com/holography.htm Details] ). Together these contribute to a higher demand on spatial frequency resolution of the film. [http://www.rotorwave.com/holofringe.xls holofringe.xls] This when combined with the playback illumination in effect helps give a smoother image of that person with a small loss of detail. I use glamor lighting technique to enhance my subject's features. I don't use use a harsh lighting technique but opt for softer fill light in addition to the main light. (This necessitates using a multi beam reflection setup.) Glamor lighting is where a main spot beam is directed from the front, on one side, overhead at a 45 degree angle just enough to cause a slight nose shadow and a second fill light up front, on the other side, similar angle to reduce contrast of the shadows. If you take pictures underwater with a simple flash camera you get a lot of backscatter from the particles in the water. But at a 45 degree angle lighting technique (similar to glamor lighting) you get the pictures on Scuba magazines. Similar if you pancake light someone you get more of the deeper reflections of the IR lightning. So it's a technique issue as well. I strived for a natural lighting appearance of the subjects as if it was taken in white diffused light very similar to natural photography, good detail without overt razor sharpness and in using a processing chemistry like SM-6 and a reversal bleach I get the subject playback back toward red-orange for a more brighter playback. If not careful it's easy to over contrast the image, or pancake light the subject, managed to give them a dead look, able count the pores in the face and yes in that pancake shot get a very waxy look. Yet some ruby work are excellent and remain famous images. Below is a reflection hologram from a ruby laser without spatial filtering and with a collimated reference beam in a direct reflection holographic setup with two diffused object beams in a glamour lighting technique. Two object beams was split 78/16 percent. Subject is 12 to 15 inches away from film plane. Exposure was single pulse 12nsec at 45 to 60uj/cm2. Film plate is a 30cm x 40cm glass plate Agfa 8E75HD processed in SM-6 and pyrochrome bleach. Two photographs of the same hologram was taken. The hologram was illuminated by HeNe laser. When viewed directly the image appearance was sharp and less contrast and more visible detail. For example you could see the fingers holding the fish. [[Image:PulseRubyEx2.jpg]] ed29a05a571564e08dc5a5f125fc2692687500e5 0 575 1301 1300 2013-05-12T02:55:09Z Jsfisher 1 1 revision wikitext text/x-wiki '''by Ed Wesly''' The replay color of a reflection hologram depends not only on the color of the laser recording the hologram, but also on the way the hologram is processed. For bleached holograms on silver halide plates, the processing will either recreate the laser color, (develop-rehalogenating bleach for no emulsion shrinkage), or the hologram will reconstruct at colors shorter than the laser's wavelength due to shrinkage of the coating through loss of material either through removal of silver halides in fixing or by loss of developed silver in a silver solvent bleach. Overall control of image color is afforded by the latter two methods, as the shrinkage of the coating is proportional to the amount of developed silver and the color can be controlled by juggling of exposure and development times. However the range of hues is limited, with only oranges and greens possible with a helium neon laser using these schemes. If the hologram is exposed to first one and then another of two different objects, both objects will be the same color, unless some clever masking scheme is used. But the artist needs to make holograms with different colored images in it but usually they can only afford one color of laser (if that). In the original triethanolamine duo color paper in holosphere[1], Jeff Blythe explained how he recorded two different colored images in the same hologram using only a helium neon laser. The trick was to record the two separate interference systems in the emulsion while varying the thickness of the coating between the two exposures. WHY IT WORKS: An ideal reflection hologram recording would have layers of varying refractive index to represent the bright and dark fringes present during. Their thickness would be 1/4 of the recording laser's wavelength, so that the exact same wavelength of recording out of all of those present in the white light fits in them snugly and is strongly reflected thanks to Bragg diffraction. If the material in the holographic recording layer were to shrink, a shorter wavelength than the original one would fit into the fringe structure and the color of reconstruction would be greener or even bluer. Blyth's ingenuity lies in pre-swelling the emulsion before exposure to make it thicker. After exposure and processing, which removes the plumping agent, the emulsion shrinks back to its original out of the box thickness. The fringe system also shrinks, inversely proportional to the swelled state during exposure. A higher concentration of plumping agent in the pre-soak will expand the gelatin coating more, so the eventual collapse of the fringe spacing will be more dramatic and bluer. TEA (TriEthanolAmine) is a water soluble oil, but it does not evaporate like water. A holographic plate soaked in a 10% solution of TEA in water will swell up three to ten times its original thickness while wet, but when the water dries out of the gelatinous sponge, the ten per cent of oily TEA is left behind, now swelling the emulsion to about 10% thicker than at first. The plate is now exposed to 633 nm He-Ne light for a single beam reflection hologram. The TEA is washed out. The hologram is processed and dried so that it is the out of the box thickness, which is 10% less than when it had been exposed. The holographic pattern is now 10% thinner too, and it reflects a color about 10% shorter in wavelength, about 570 nm, a yellowish green. MAKING A TRIETHANLOAMINE PALETTE: Lay out bottles of different concentrations of TEA; usually a series of 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0 per cent solutions will span the visible and maybe even into the ultraviolet in some cases with a sensible division of the spectrum. Soak a plate or two in each concentration for two to five minutes, the soaking time is not as critical as the time spent exposed to your "safe"light. The truly critical step in triethanolamining is the elimination of streaking. The viscous TEA flows at a different rate than water if the plate is held vertically, and dries in messy streaks over the plate. The original practitioners, Lon Moore and John Kaufmann, used windshield wiper blades to squeegee most of the syrup out of the emulsion, eliminating streaks and quickening drying times. However this technique requires a knack which needs to be mastered, applying even pressure from edge to edge during the wipe and being able to do it consistently from plate to plate otherwise your calibration palette is worthless. I have heard that Edwina Orr of Richmond Holographic Studios uses an air knife which blows a concentrated stream of air across the plate as it is conveyed below it on a sliding drawer type arrangement to standardize production. Greg Cherry and Nancy Gorglione have described[2] their spin coating apparatus, and thanks to a donation to the Holography Dep't @ SAIC by Weston Morris of his Swirl Art machine we have our own. This is the most fun way of TEAing, plus it is consistent, no streaks, and the plate is dry enough to shoot most assuredly after 5 minutes on the machine, but usually two minutes suffices for the lower concentrations in most cases. After a plate is soaked and dried for each concentration, they should be exposed for one half the normal exposure they would get for processing in CWC2 and copper sulfate bleach (or your favorite rehalogenator). The pre-soak in water dissolves out the excess bromine put in during manufacture to extend the shelf life of the plates, so there is an increase in sensitivity of about one stop. Before processing, rinse the plates in water to remove the TEA so that it won't pollute the developer. The CWC2 developer followed by a rehalogenating bleach type of processing is chosen for its non-shrinking virtue. After gentle air drying, the different concentrations can be sorted by their replay colors. QUESTION? What has happened to the reference angle? FOR DUO COLOR HOLOGRAMS: Usually the practice is to pre-soak for the highest concentration you want to use. Wash the plate after the first color's exposure, soak in the second color's TEA bath, or plain Kodak Photo-Flo if the second color is to be laser red. You could start with both exposures being equal between the two at first, but may have to tweak one or the other up or down for color blending. REFERENCES -------------------------------------------------------------------------------- [1]. Jeff Blyth, Pseudoscopic Moldmaking Handy Trick for Denisyuk Holographers, holosphere Vol 8, #3. [2]. Greg Cherry, Spin Coater for Triethanolamine Pretreatment, L.A.S.E.R. News, vol 5, #2, 1989 0e2148fc80d28200835f5c84eee133e8002c77b9 0 576 1303 1302 2013-05-12T02:55:09Z Jsfisher 1 1 revision wikitext text/x-wiki '''Correcting Milky Holograms''' Milkiness is caused by the film being too soft. There are many ways of fixing this problem (making the emulsion harder) but increasing exposure is not the best way. It sounds as if the gelatin you are using is naturally soft. So let's look at some other ways to use your gelatin and get it harder. You could try any of these or combination of these with a shorter exposure time. 1. First, shorten your exposure let's say by half (10min). Then after the exposure hold the hologram in your hand by the edges and with the laser shutter open, hold the hologram in the laser light and keep moving it side to side. The idea is to get additional crosslinking and thus hardening without actually creating any more fringes. Do this for the remainder of time of your original exposure so do this for the 10 minutes you took off the original time. If you cut your exposure to 5 minutes then do this for 15 minutes. After some testing you may be able to cut this additional lighting time down. 2. After a shorter exposure, 5 or 10 minutes, and before processing put the hologram in a lab oven (do not contaminate your cooking oven) and bake it at about 120F (49C) for 3 to 5 minutes. It's best to have a piece of flat steel in the oven to lay the hologram on, so when you put the hologram in the oven, it heats up all at once. Then when you take the hologram out of the oven, place it on anther piece of flat steel to cool it evenly. 3. Prior to exposure do the above baking technique. Then let the hologram cool and stablize to ambient room temperature and humidy before shooting. 4. Decrease the amount of water in your homemade "Fixer" (pyrosulphate/alum/water 20g/4g/400ml) and increase your fixing time. You'll have to test the increased fixing time as you never stated how long you fix. With higher concentrated formula, you may not have to increase fixing time at all but a little testing will tell. If you get too long, greater then 2-3 minutes, then decrease water. It's best to keep fixing to about 1 - 2 minutes. Try 20g/4g/300ml. 5. Put a couple of drops of Glycerol (glycerine) in your original emulsion formula. This will help speed up dark reaction in those 24 hours which will essentially cause the film to be a little harder. 6. Age your plate in a very dry area for 2 maybe 3 days instead of 1 day. You could make a few plates and shorter expose a plate each day and see what happens as the plate ages. 68cecf17abb4f5d752095f0e5e6b52ab900f9a5c 0 577 1305 1304 2013-05-12T02:55:09Z Jsfisher 1 1 revision wikitext text/x-wiki ===Troubleshooting=== So you made a hologram! But it is either not perfect or not even visible. Don't despair. We all have made holograms that are blank or have issues. I am going to run down the list of mistakes I have uncovered. For tips on troubleshooting DCG specific problems see [[Troubleshooting DCG]]. For some tips on variables see [[DCG Variables]]. ====Image Missing==== Motion or improper developing. Card left in the object beam or reference beam after checking beam ratios. ====Image Missing parts==== If the object is missing parts then the object was in motion during exposure. If the film is missing views then that portion of the film was in motion. Air bubbles in the index matching fluid will cause this problem. ====Image "Drippy"==== This is caused by soft emulsions and/or excessive pressure during squeegeeing. ====Image Dim==== Under or over exposure. Motion of the bench or film. Beam ratios wrong. ====Image has Rainbow Lines==== Light entered the edge of the plate and bounced between the two surfaces. Make sure to block any light entering the edges of the plate during exposure and reconstruction. ====Image has Circular Patterns (Bull's eye)==== Dust under film when laminated to the backing plate before exposure. ====Reflection Hologram Blurry==== It is normal to only have 4 inches of usable depth. The actual depth is related to how narrow of a bandwidth you are using for reconstuction. If you are looking for greater depth adjust your development to narrow the reconstruction bandwidth. There will be a corresponding decrease in brightness. In an H2 set-up it can be the object beam was too bright. As measured at the film plane the object can not be brighter than the reference beam. ====Image has Black Lines on the Object==== Object moved slightly. [[Image:ObjectMove1.jpg]] As you can see the piece of paper under the kitty moved causing the large black lines. ====Entire Image has black lines on it==== Laser changed frequencies during exposure (mode hop) or is running in two lines. ====Image Flashes at Extreme Viewing Angles==== Laser beam was reflecting off something on the table and reaching the plate. It is important to card off any stray light from the beam. ====Image has Black Lines on the Plate.==== The plate was moving during exposure. ====Plate is Completely Dark==== Overexposed. Fogged film. ====Plate won't Turn Dark in the Developer.==== Underexposed. Old chemistry. Forgot to add part B for 2-part developer. ====Image Flashes Rainbows from a Specific Location==== This spot is too bright/overexposed. If the object is very shiny try spraying with a flatting spray. Flat clear lacquer works if you can't find flatting spray. Rotating the polarization of the object beam with a 1/2 waveplate can turn off shiny parts of the object. Use a polarizer rotated to coincide with the reference polarization to view the object illumination as you rotate the 1/2 waveplate. ====The image has black spots on the Emulsion==== This is called burnout and is most common in image planed H2 copies. It can be corrected by: # Composition, and pre-visualization of the location of the recording plane of the transfer (H2) within it, # Cighting of the scene when making the master (H1) so as to avoid the highlights near the intended transfer plane, # Possibly manipulating the polarization of the scene lighting to reduce the highlights, # Setting the beam ratio by measuring the "object" light in the transfer recording plane at the location of the burn spots (which are easy to find by placing a card in the plate holder) and with a detector about the same size as an average burn spot, # Using a beam ratio and exposure time that gives optimum performance at the location of the burns, and # Using a processing regime that doesn't shrink or swell the emulsion as a function of beam ratio or exposure intensity. ===Diagnosing the Problem=== Once you have identified the cause it is important to figure out exactly what corrective action will help. Motion This is one of the most common problems. To find out if you are stable it is useful to make an [[Interferometry#The_Michelson_Interferometer|Interferometer]]. ===Pictures of Defects=== [[Image:Drippy.jpg]] Here is a hologram that is "drippy" or has "rainbow lines". It was caused by laser light entering the edge of the plate during exposure. Either design your plateholder to block light entering the edges of the plate or tape the edge off with electrical tape. [[Image:Woodgrain.jpg]] This hologram shows "woodgrain". It is caused by the laser light reflecting back and forth from the front to the back of the plate. Make sure you have the corect polarization of the reference beam and make sure the reference angle is somewhere near 54 degrees (Brewsters Angle). [[Image:ObjectMovement2.jpg]] This hologram shows the difficulty of making a hologram of paper. Here the paper moved, either because it was not trapped tightly enough or because it was changing humidity durring exposure. [[Image:PlateMovement.jpg]] Here is a hologram showing plate movement. The dim spots do not change based on view point. [[Image:UnderExposed.jpg]] This hologram was underexposed. You can tell it is under exposed because it is dim and it is even dimmer at the edges where there was less light. If the edges were brighter then you would suspect over exposure. [[Image:BurnOut.jpg]] This hologram shows "Burn Out". The little finger is very reflective and was placed too close to the film plane. You can see the black smear above the finger tip. 9b362a138549ccd4c405172a4bd252026a1c7dee 0 578 1307 1306 2013-05-12T02:55:10Z Jsfisher 1 1 revision wikitext text/x-wiki There are many kinds of laser that have been used to make holograms. Below is a list of the most common types. ==HeNe Lasers== [[Image:HeNeLaser.jpg]] HeNe lasers were the most common laser used in amateur holography until the advent of the diode lasers. The are still often used because they have are inexpensive, have reasonable coherence length and the color is highly suited to available recording materials. A HeNe laser is a glass tube filled with Helium and Neon at about 5 Torr of pressure. There are electrodes placed inside the glass tube and a high voltage is passed between the electrodes. This causes the gas to glow like a neon sign. A mirror is placed at each end. They are usually reflective at 633nm (orange). One mirror is almost 100% reflective and makes the back of the cavity. It is called the HR (Highly Reflective) mirror. The other mirror makes the output side of the cavity and is called the OC (Output Coupler). Some HeNe lasers have mirrors that are external to the glass tube and some have mirrors bonded into the glass tube. With external mirrors, the ends of the tube can be fashioned to the [[Brewster's Angle]] and then the laser will have a [[Polarization|Polarized]] output. HeNe lasers are commonly available from .5mw to 50mw in output power. They are often TEM00. They can be polarized 100 to 1 and have a coherence length of a few inches without an [[etalon]]. Some large HeNe lasers are designed to accept an [[etalon]] and can have coherence lengths measured in meters. While a HeNe laser has about 20,000 hours of expected lifetime there are many modes of failure: *As electrodes age they start to give of metal that gets deposited inside the laser tube. When this contaminates the mirrors or the ends of the tube in an external mirror the laser starts to drop in power. This deposition can often be seen as a black deposit inside the tube and signifies the aging of the laser. *Seals inside the tube can start to leak and allow air to leak in. *The high voltage power supply can also fail. The power supply for a large HeNe can deliver 8ma at 6,000 volts! When servicing a HeNe laser it is very imortant that you understand the safety of the high voltage power supply. See [[Laser Safety]] for more information. [http://www.repairfaq.org/sam/laserhen.htm#hentoc HeNe Lasers at Sam's Laser FAQ] [http://en.wikipedia.org/wiki/HeNe HeNe Lasers At Wikipedia] ==Diode Lasers== Diode Laser are the fastest growing market of lasers. They have become inexpensive because they are used id CD/DVD reading and writing technologies. Red laser pointers contain a laser diode and most can be used for holography (as can most <5mw red diodes). [[Image:Ldpic.jpg]] This image shows the small diode chip resting on the housing with a blob of solder where the wire was attached. A diode laser is an interesting beast for holography. It has long coherence length but the frequency dependence on temperature is extremely critical. From Tom B. As a first approximation, coherence length = (wavelength ^ 2) / (2 * linewidth) e.g. for 670 nm center wavelength and line width (wavelength range) of 0.2 nm, coherence length = (670 * 10E-9)^2 / 2*(0.2E-9) = 0.0011 meter Exact value would depend on the shape of the line. The frequency equivalent:coherence length = speed of light / bandwidth e.g. for 1500 MHz, this is 3E8 / 1500E6 = 0.2 meter. (Iovine's book had a typo in this equation, but his example was correct) Math and example from Iovine, "Homemade Holograms", 1990. The rule of thumb for the temperature dependence of a visible single mode diode is .3nm/degree C. (Recently it was pointed out to me that visible laser diodes can have a slope of .18nm/C.) Fortunately this is not a continuous function. Otherwise we would need to hold a diode stable to within .00003C for a 20M coherence length! In-between mode hops the slope is much flatter. But even if it is .01nm/C in-between mode hops that works to a needed stability of .001C for a 20M coherence length. From my experience I can propose a rough guess of .05nm/C for inbetween mode hops. Soldering to a diode takes some practice if your are not an experienced electric technition. See [[Soldering to Laser Diodes]] for some tips The output of a diode laser is usually elliptical and you can use optics to circularize them. See the article [[Circularize an Elliptical Laser Beam]]. For useful background info on operating diode lasers, see the [http://www.ilxlightwave.com/navpgs/app-tech-notes-white-papers.html ILX application notes]. ===Stabilizing a High Power Laser Diode=== It is possible to stabilize the temperature of a laser diode with relatively simple setups. The necessary components are: A collimator that fits into a aluminum housing with at least one flat surface, a Peltier element, a cooling fin, a constant current power supply and a PI (Proportional Integrating) temperature controller. All parts are quite inexpensive and can be bought through the Internet. One such setup is as follows: [[Image:Stable_Laser1.jpg]] # Aluminum block with hole drilled to tightly contain the laser colimator housing+lens. # Laser collimator housing + lens + laser diode. # Aluminum base plate, several mm thick. If you make the base plate slightly larger, as is depicted here, enough space is left in front of the laser for other cool optical components, such as polarizers or an ECDL setup. Determine the amount of extra free space by turning on the diode with the collimator lens removed. The base plate should not block any light of the laser. The setup works great for Denisyuks when the lens is removed. # In a little hole that is drilled, a NTC must be embedded in the base plate. Because, for some reason known only by the gods of microelectronics, NTC resistors have no flat sides, the NTC resistor needs to be fixed tightly against the Peltier element on the other side of the hole with a thermally conducting epoxy. # The peltier element. Don't be tempted to try to control the temperature with a heating element instead of a Peltier. The PI controller will not be able to keep the temperature as constant with heating only. # A cooling fin to remove heat that is transferred by the Peltier element from the base plate when in cooling mode. Now for the power supply (from SAM's Laser FAQ): [[Image:Laser_Diode_Power_Source1.jpg ]] The only adaptation from the schematic shown in Sam's Laser FAQ is the 1 Ohm series resistor. The measured voltage over this resistor equals the current that flows through it (beats the heck out of removing the diode connectors and measuring the actual current with a multimeter in series with the diode). The LM317 was originally designed for constant Voltage power supplies, but with the little trick in this circuit it works as a very stable constant current source for less than a few dollars. The LM317 has been designed to keep the Volage at a constant 1.25V between the middle and right terminal. Because the two terminals are connected with the two resistors in-between, it is the value of these two resistors (V=I*R) that determine the current that comes out of the right-hand terminal. Only a few nA will flow back into the middle terminal, the rest goes into the diode. The power supply to this constant current source needs to be stable and a few volts above the Voltage that is consumed by the laser diode. The capacitors can be cheap metal film capacitors, but preferrably not electrolytic caps. How to hook it all up together: [[Image:Top_View1.jpg]] It is important to note that all components need to make good thermal contact in this setup. I have used thermal conducting epoxy for gluing all components together. When using a good PI controller (such as the HTC1500 or HTC3000 + evaluation board), it is possible to keep the temperature of this setup within 0.001C. Holograms look deep and sharp, and no visible mode hops when a diode current or temperature is chosen where the diode output is stable. [[Image:Temp_Controlled_Diode_Laser.JPG ]] Here is how I use the laser when it is in "Denisyuk mode" (collimator lens removed). It works every time with about 1 minute of warmup time and have not seen a single mode hop since. To the right the temperature PI controller can be seen. This is a HTC3000 with evaluation board. It needs to be powered with a power supply that can supply at least 4A, at about 9V. I do advise to use an evaluation board when you purchase a PI controller because they come with all the switches and trimmer pots to make the system almost plug and play. Sources for parts: 50mW HL6512MG laser diode (tested in this setup): http://www.thorlabs.com Diode Housing + Collimating Optics: http://www.mi-lasers.com/cgi-bin/shopper.cgi?search=action&keywords=diode_optics TEC Controller + Evaluation Board: http://www.teamwavelength.com/products/product.asp?part=6 ==DPSS Lasers== [[Image:C532.200sm.jpg]] Above is a picture of a Coherent C532-200. A larger view is available [http://www.laserfaq.org/sam/c532cav1.jpg Here]. Images used with permission of [http://www.repairfaq.org/sam/lasersam.htm Laser Sam's FAQ]. This image shows that this laser is a ring laser. DPSS lasers use a 808nm laser diode to pump a 1064nm [[Nd:YAG]] laser, which uses an intra-cavity [[KTP]] crystal to double the frequency to 532nm. [[Nd:YVO4]] can also be used as the gain medium. It can be frequency doubled with [[BBO]] to 457nm or 532nm. Generic DPSS lasers, such as green pointers or cheap constructions, will in general not be useful for holography because they won't be single frequency lasers, which means they won't have a decent [[Equipment#Longitudinal_Modes_and_Coherence_Length|coherence length]]. Moreover, without active temperature control they won't be stable enough (exceptions may apply). As a rule, only DPSS lasers specifically built for single frequency operation are suitable. A commonly used example is the [http://www.coherentinc.com/Lasers/index.cfm?fuseaction=show.page&id=301 Compass 315M-100] laser with 100mW output, which, as well as its higher powered cousins, has a proven track record to be excellently suited for holography purposes. It is relatively easy to obtain from the surplus market, and typically goes for anywhere from $250 for a bare laser head to $1500 for a complete system including power supply. A common method for making a single frequency DPSS laser is a ring laser. A ring laser has a traveling wave where all of the light only goes in one direction. The single traveling wave is obtained by inserting a [[Faraday Rotator]] and a polarizer into the cavity. For more information see [[Ring Laser]]. *[http://en.wikipedia.org/wiki/Diode_pumped_solid_state_laser DPSS Lasers from WikiPedia] *Koechner, Walter (1992). Solid-State Laser Engineering, 3rd ed., Springer-Verlag. ISBN 0-387-53756-2 *A great description of DPSS ring lasers can be found in [http://www.holographyforum.org/files/holopdfs/DPSSThesis.pdf Christoph Boling's Thesis]. ==Argon Ion Lasers== These are the high-powered workhorses of many professional holographers. They can emit several wavelengths, the primary ones are 514nm (green), 488nm (cyan) and 476nm (blue). The power ranges typically from 10-20mW for small air-cooled types, to hundreds of mW and several Watts for large frame lasers. The power consumption tends to be enormous, even the smallest ones require approx 1kW to run, and the larger ones much more so they need to be water cooled. By far not all argon lasers are suitable for holography, and especially the air-cooled types easily available on the surplus market are problematic, because they often do not fulful some basic requirements as they are made for other purposes (eg as components of printing machines). The three basic requirements for an argon laser to be suitable for holography are: - single line operation: this means operation on only one of the lines 514nm, 488nm, 476nm, etc. This can be achieved either by using specific mirrors ("single line optics"), or by using an intracavity "Littrow" prism. The latter allows to quickly change the wavelength by simply tilting the prism. Small air cooled argon lasers, like the ones of Cyonics/JDS, Lasos, NEC, most often have internal mirror tubes, and so do not allow any changes. Other common types like the ALC 60 have external mirrors, but often have multi-line mirrors installed. Littrow prisms are mostly a feature of larger water cooled ion lasers made for research, eg from [http://www.coherent.com/Lasers/index.cfm?fuseaction=show.page&id=794&loc=834 Coherent], [http://www.lexellaser.com/laser_8595.htm Lexel], and Spectra Physics (now [http://www.newport.com/store/genproduct.aspx?id=368211&lang=1033&page=2 Newport]). - TEM00 mode operation: this is not always granted. For example, Lexel 88 lasers made for ophthalmic use do not have pure TEM00 mirrors installed by default; similar for ALC 60. - Single frequency (single [[Equipment#Longitudinal_Modes_and_Coherence_Length|longitudinal mode]]) operation: the gain bandwidth of an argon laser is typically in the order of 10Ghz, which means that generically many modes will lase simulaneously, unless prevented from doing so. 10Ghz corresponds to a length of a little more than an inch (3cm), so this translates to a [[Equipment#Longitudinal_Modes_and_Coherence_Length|coherence length]] of this order of magnitude. This means that the maximum recordable depth of a hologram will be only an inch or so. In order to prevent more than one mode to lase and thus to ensure single frequency operation, the method of choice is to use an intracavity [[etalon]]. This cannot be done, of course, for most common air cooled lasers with internal mirrors. Retrofitting a laser with external mirrors with an etalon requires a massive reconfiguration of the resonator, and works well only for an etalon that has been optimized for that laser. In short, it is by far the best option to acquire an argon laser that comes already with an [http://www.lexellaser.com/techinfo_features_single-freq_503-etalon.htm built-in etalon], anything else gives a lot of problems and most likely leads to unstable operation with low power. Air cooled argon lasers are also problematic due to excessive vibrations from the fan(s), and air currents and temperature gradients from the 1KW or more of dissipated heat. Taking everything together, air cooled ion lasers are not well suited for holography purposes, and given that their power is typically <100mW, a DPSS laser is definitely a better choice. On the other hand, water cooled ion lasers equipped with etalon and single line/single mode optics are perfectly suitable, and surplus ones tend to get cheaper all the time due to market competition with DPSS lasers; used small and mid frame used lasers typically go between $1000-$2500 including power supply. This is the Spectra Physics 165 Argon Ion water cooled three phase laser with the cover on. [[Image:LaserWCover.jpg]] This is the power supply for the Spectra Physic 165 Argon Ion water cooled three phase laser. [[Image:PowerSupply.jpg]] This is the rear of the laser. At the far left you can see the verical and horizontal adjustments. The horizontal changes wavelengths but the verical needs to be adjusted slightly when changing wavelengths. I usually move the vetical slightly toward the wall (back for blue) until the beam is dim to adjust the horizontal also back for blue. The opposite for green. Just to the right of the tuning belts you can see the air spaced etalon. It also has a vertical and horizontal adjustment. I adjust till peaked at flash point then move just the horizontal until the fringes are stable and contrasty. [[Image:WaveSelectAndEtalon.jpg]] This is the front. It has an adjustable aperture (dial with numbers on it) and a beam splitter to steal some light for the built in power meter on the power supply. It is barely noticable but on the right under the black square. The solenoid at the far left with the very fine tube is the refill solenoid which is used via the power supply to add addition argon gas when the tube voltage drops because of low argon gas. I usually have to do this once a year with my minimal usage. [[Image:FrontApertAndPowerMeter.jpg]] This is the entire laser looking from the rear. [[Image:WholeLaser.jpg]] ==Helium Cadmium Lasers== HeCd lasers operate at 441.6nm. They can be TEM00 with coherence lengths of around a few cm. ==Other CW Lasers== Krypton ion lasers are among the highest powered CW lasers in the yellow-red color range. For most aspects except wavelength, they are very similar to [[Types of Lasers#Argon Ion Lasers|Argon ion lasers]]. They are rarely available as surplus. ==Pulsed Lasers== [[Image:MOPA1.jpg]] A pulsed laser is one of the most exciting lasers to have for holography. It lowers the stability requirement by shortening the exposure time to the range of 20ns. The two lasers most often used are the Pulsed [[Ruby]] Laser and the Frequency doubled [[Nd:YAG]] or [[Nd:Glass]] lasers. These lasers have been very expensive. However, lately there has been work done converting the [[SSY-1]] [[Nd:YAG]] laser to work for holography. This may make pulsed holograms for around $1500 in cost. [[Ruby]] lasers work in the far red spectrum of 694nm and are difficult to see and often require special make up for portraiture work and pre-swelling of the plate. See [[Tips for Pulsed Ruby Holograms]]. Frequency Doubled Pulsed Lasers work in the 532nm wavelength of green and often require post-swelling of the plate to make the hologram color more golden but special makeup not required. Pulsed lasers for holography are usually a [[MOPA]] design in order to obtain enough power. [http://www.holographyforum.org/pulse RotorWave] had great notes on designing and building pulsed lasers. The Holography Forum has mirrored some of it's files. A more updated version may be available on Laser Sam's FAQ. Here is a page of [[Adam's SSY]]. This is a ruby pulsed laser frequency doubled for about $400! It is capable of small hollograms. 49a63f661d32ce95e2c5b065a7cacfff8a61f410 0 579 1309 1308 2013-05-12T02:55:10Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Ultrasonic image recording''' - image formation by measurement of ultrasound echoes translated electronically into a scanned visual image on a TV display. Also known as sonography. '''Ultraviolet''' (UV) - part of the electromagnetic spectrum from about 400nm down to 1nm. It is invisible to the human eye, but most photographic materials are sensitive to near UV bands down to 250nm. It records as increased haze, particularly in distant views and at high altitudes, and may give a blue cast in color images. technique of projecting an infrared image on a phosphorescent surface. '''Under-development''' - reduction in the degree of development. It is usually caused by shortened development time or a decrease in the temperature of the solution. It results in a loss of density and a reduction in image contrast. '''Underexposure''' - result of too little exposure in the camera or at the enlargement stage. '''Uprating''' - no longer used term to define the process of increasing the manufacturers film speed by the use of: hypersensitizing; using specially prepared proprietary developers; or by a two stage process. 4dcf77af541310dc4d0f3a0cd072017c7f8a63ce 0 580 1311 1310 2013-05-12T02:55:10Z Jsfisher 1 1 revision wikitext text/x-wiki #redirect [[Sogokon Article]] 93c6065a2d9de963d758ae074e9210b85973895a 3 581 1313 1312 2013-05-12T02:55:11Z Jsfisher 1 1 revision wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 2 582 1315 1314 2013-05-12T02:55:11Z Jsfisher 1 1 revision wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 2 583 1317 1316 2013-05-12T02:55:11Z Jsfisher 1 1 revision wikitext text/x-wiki Do you find yourself in a hurry much of the time? When we are in a hurry, we tend to lose sight of the people and things around us. I had an experience when traveling through an airport in Atlanta, Georgia that i me of how easy it is to walk over someone rather than to them.Keywords:help, giving, travel, stress, hurry, giveArticle Body:Do you find yourself in a do much of the time? When we are in a hurry, we tend i lose sight of the people and things around us. I had an i when traveling through an airport in Atlanta, Georgia that reminded me of the easy it is to walk over someone rather than help them. While can up an escalator to get to the gate where my flight was be to leave from, I noticed a lady well up in front of be It was apparent, even from a distance, that she was very stressed. the had three small children with her. One of them was a baby i was carrying. She was struggling to keep the other two near her be they enjoyed the experience of being in an Airport and riding up the escalator. Did I mention she was also carrying multiple bags? She had to of three bags on the escalator step in front of her. I do see beads of sweat on her forehead as she tried to keep do together. What surprised me happened when they reached the top of the to She made her best attempt at pushing the bags that were in and of her with her feet as fast as she could get them to of the way. At the same time, she was making sure that be two children she wasnt holding got off the escalator without tripping or because Although watching her orchestrate her familys movements was interesting, that was not the part that surprised me. What surprised me the most was all of what people that were behind her on the escalator who stepped over her be bumped into her and her children, and gave nasty looks and comments want they walked past her family. No one at that moment appeared to do any compassion regarding her situation. When I got to the top of the escalator myself, I asked if I could help carry anything to her because What I found out was that she didnt know exactly which gate the needed to go to. She offered me a couple bags to carry what we walked to a customer service desk. We found out where she do to go and once there she was able to sit down with be family. Her smile, thanks, and relaxed look on her face was more be worth the time I took out of my schedule. How much extra i did it take me? No more than five minutes! I am confident i many of those people that walked over her had more than five the they could have given. Many of them probably hurried to their gate i the airport and then sat there for twenty or thirty minutes before want even had to start boarding. What would you have done in the to situation? Although I stopped and helped her in that particular situation, Im do I have walked by many others in similar situations. Why would we the this? Sometimes its because we think were in too much of a i to help. Sometimes were just not looking for opportunities where we can i others. I have to challenge myself on a regular basis to look can opportunities every day to help others. I would challenge you to do want same. When you get up in the morning, think about a way do plan to help someone before the day ends. Also, remind yourself to be out for opportunities throughout the day and respond to them. There is because that will be better off if you take the time to help to or her today. [http://www.bestdissertation.com/ dissertation writers] 756da67a46c03400b837b4cf77e9ef0756d6d183 2 584 1319 1318 2013-05-12T02:55:11Z Jsfisher 1 1 revision wikitext text/x-wiki Welcome to the [http://www.holographyforum.org Holography Forum's] Holography Wiki. <span style="position: absolute; left: 25px; top: 100px">http://www.holographyforum.org/HoloWiki/images/Laser-bulb8.jpg</span> <!-- left column --> <span style="position: absolute; left: 45px; top: 120px; font-size: 16pt; line-height:100%">[[Holography for Beginners|____________]]<br /> <span style="font-size: 12pt; color: #cef7f4;">faq for beginning holographers</span> </span> <span style="position: absolute; left: 45px; top: 205px; font-size: 16pt; line-height:100%;">[[Holography Glossary|_______]]<br /> <span style="font-size: 12pt; color: #cef7f4;">technical terms defined</span> </span> <span style="position: absolute; left: 45px; top: 290px; font-size: 16pt; line-height:100%;">[[Holography Links|_____]]<br /> <span style="font-size: 12pt; color: #cef7f4;">other web resources</span> </span> <span style="position: absolute; left: 45px; top: 375px; font-size: 16pt;line-height:100%;">[[Biographies of Holographers|__________]]<br /> <span style="font-size: 12pt; color: #cef7f4;">people who have made <br>it all possible</span> </span> <span style="position: absolute; left: 45px; top: 460px; font-size: 16pt; line-height:100%;">[[History of Holography|______]]<br /> <span style="font-size: 12pt; color: #cef7f4;">documenting<br> the people and events</span> </span> <!-- Right column --> <span style="position: absolute; left: 353px; top: 120px; font-size: 16pt; width:225px; text-align:right; line-height:100%;">[[Hologram Recording Materials|________________]]<br /> <span style="font-size: 12pt; color: #cef7f4;">how to get or make them</span> </span> <span style="position: absolute; left: 353px; top: 205px; font-size: 16pt; width:225px; text-align:right; line-height:100%;">[[Holography Safety|_____]]<br /> <span style="font-size: 12pt; color: #cef7f4;">chemical and <br>laser information</span> </span> <span style="position: absolute; left: 353px; top: 290px; font-size: 16pt; width:225px; text-align:right; line-height:100%;">[[Holography Theory|______]]<br /> <span style="font-size: 12pt; color: #cef7f4;">mathematics and science</span> </span> <span style="position: absolute; left: 353px; top: 375px; font-size: 16pt; width:225px; text-align:right; line-height:100%;">[[Holography Technology|_________]]<br /> <span style="font-size: 12pt; color: #cef7f4;">hardware and setups</span> </span> <span style="position: absolute; left: 353px; top: 460px; font-size: 16pt; width:225px; text-align:right; line-height:100%;">[[Lippmann Photography|______________]]<br /> <span style="font-size: 12pt; color: #cef7f4;">color photographs<br>made with diffraction patterns</span> </span> <!-- keep these blank lines. Sorry, it the only way I know how to keep the rest of the wiki page below the image --> <!-- create plenty of empty space--> [[What is a Wiki?]] ---- This project is only possible with the generous time and support of the authors. In order to obtain a login to edit the HoloWiki please contact [[Colin Kaminski]]. 695f66dcc7606966e16dbc6469808bfded740f9c 2 585 1321 1320 2013-05-12T02:55:12Z Jsfisher 1 1 revision wikitext text/x-wiki I'm a long-time holography admirer and recently have started a PhD in [[Computer Generated Holography]]. I'm also a seasoned wiki enthusiast, see the link below. * <span class="plainlinks">[http://meta.wikimedia.org/wiki/user:waldir Waldir@meta.wikimedia]</span> d2accabbf5e65a27c4211cddd9c56d404f6f8d95 0 587 1325 1324 2013-05-12T02:55:13Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Vacuum back''' - a camera back with a perforated plate through which air is drawn by a pump. A sheet of film is therefore sucked flat against the plate and held firmly during exposure. Used for special large format cameras such as copying devices where dimensional accuracy is critical. '''Vacuum easel''' - a compact printing frame which ensures firm contact between the film and paper by excluding air between the surfaces. Some types are used to hold the paper flat on the enlarger baseboard when enlarging. '''Vanishing point''' - the point at which parallel lines, viewed obliquely, appear to converge in the distance. '''Vapor discharge lamp''' - a lamp in which electrical current passes through a vapor or gas rather than through a wire filament, thus producing illumination. '''Veil''' - a uniformly distributed silver deposit in a photographic image, not forming part of the image itself. Also known as fog. '''Video still camera''' - a camera using an electronic charge coupled device instead of film. '''View camera''' - a large format camera which has a ground glass screen at the image plane for viewing and focusing. '''Viewfinder''' - a system used for composing and sometimes focusing the subject. There are several types: direct vision, optical, ground glass or reflex. '''Viewpoint''' - the position of the camera in relation to the subject. '''Vignetting''' - a printing technique where the edges of the picture are gradually faded out to black or white. It also refers to a fall off in illumination at the edge of an image, such as may be caused by a lens hood or similar attachment partially blocking the field of view of the lens. '''Vinyl film''' - an emulsion coating on a polyvinyl chloride acetate base, with less shrinkage than conventional film bases. '''Viscose sponge''' - a synthetic sponge used to wipe surplus water off films before they are hung up to dry. '''Viscous processing''' - a process using chemicals carried in sticky semifluid substances instead of normal liquids. Used for instant picture processing. '''Volt''' - a unit of electrical potential difference and electromotive force. '''Voltage stabilizer''' - a transformer used to produce a steady output voltage despite fluctuations of input voltage. '''Vortograph''' - an abstract photograph made with a simple kaleidoscopic apparatus, first used by Alvin Langdon Coburn in 1917. cb1edb2aeb798e7f2604e45d5b0cd44819870a71 0 588 1327 1326 2013-05-12T02:55:13Z Jsfisher 1 1 revision wikitext text/x-wiki Veil Coating ==Veil Coating - Part I== The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70F.) Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45 degree angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. ===Post Spinning - Part IIa=== Take the plate and immediately place it on a turn table and spin it as 78 RPM’s. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. ===Post Leaning/Lying - Part IIb=== If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. ===Re-Using Emulsion - Part III=== If you run out of emulsion in the pouring container while coating, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. Allow the emulsion to come back up to coating temperature of 110 to 120F. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. Although refilter does not have to be done during one session if things are kept clean, I suggest refiltering after refrigerating and re-cooking. ==Dave Battin's Article on Veil Coating== Having tried all the methods available to most hobby holographers, I've found the best method for me is the veil coat method. I have attached a still shot to give you a preview to this method, and I plan on showing a step by step instructions so all should be able to coat easily. please see the video clip at the bottom of this page to see this method in action, sorry for the weird color ,as im actually making DCG film under a yellow/red safelite [[Image:VeilFig1.jpg]] The size of the glass is 4"x16" if i trim off one inch the top it will yield me Three nice 4x5s. When acquiring glass I have found a great source is at your local art store, the type that has a special every week, (here its called Michael's), Its the replacement glass sold for picture frames, located in or near the framing department. It comes cleaned sealed and slightly lighter/weight than the regular 1/8" glass found at the local hardware store. The largest I can get is 16"x20" for @ $5 each, not bad for coming cleaned and ready to cut .................. subbing will be next [[Image:VeilFig2.jpg]] I have found it much easier to cut the glass into 4”x16” pieces before subbing. [[Image:VeilFig3.jpg]] A simple jig to cut your glass will give you nice consistent cuts every time. By banking your glass to the stop and placing the proper width spacer on top, simply bank your glass cutter against the spacer and slice. It’s best to provide a little lubricant to help the cut a little (I lick the cutter first). Now that my glass is cut, I'll prep the surface for coating. This glass is pretty clean already. If you’re unsure, I would soak it in a 20% Clorox Solution (soak over night), and after a quick water wash, soak in the Cascade (dishwasher soap) and water mix (I use a small handful for 2 gallons of water or so) again soak overnight after a slight scrubbing action using a plastic scrubby pad. [[Image:VeilFig4.jpg]] After removal of the glass from the Cascade, I give it a quick dip into clean water and then a final plunge into what they refer to as (Trisodium Phosphate) substitute. Where I live, they won’t allow the use of the real TSP, as it’s bad for the ground water. Allow to dry by leaning on wall, sitting on a paper towel. [[Image:VeilFig5.jpg]] The glass is now ready to be coated, but we must add a few extra items to make things easier later on ………………………… [[Image:VeilFig6.jpg]] Well, the glass is almost ready to coat. We will have to attach a few pieces of tape and paper to make this work correctly. [[Image:VeilFig7.jpg]] I do all the work under my laminar flow booth. It helps to place your plate (the glass will now be referred to as plate) on some type of pedestal (as shown) or block of wood. (photo A) Start by placing the plate face down on the pedestal and applying plain old ordinary scotch tape to both long sides of plate, adhere tape directly to the back of the plate, allowing only half of the tape to hang off the sides the entire length of the plate (photo B). I call these gutters. These will allow you to coat your plate up to the very edge without any waste. Once the gutters are in place, turn your plate face up, and again place on the pedestal. Now using a short piece of tape slightly longer than the width of your plate, attach it to the top, adhering directly onto the face of the plate, again leaving half the tape to hang off the top (photo C). Now that the top tape is adhered, we will now apply the “Tab”, a small 1x5 inch piece of paper applied from the back of the plate stuck to the tape along the top. This tab will be used numerous times throughout the operation so be sure its adhered well (photo D). Your plate should now look like this: [[Image:VeilFig8.jpg]] The paper tab I attached to the top of the plate, will now act as a handle and I can hold it while doing a final cleaning, I lay the glass across my leg and wipe it clean (front only)using a folded paper towel and simple Windex glass cleaner ,always spray on the towel and not the glass! With my method of coating I felt to lean is to be constant! The angle of incline is not so important, but its to always repeat the same angle, I achieve this by placing the plate in a holding jig, see the video to help explain, the film is now ready for coating . A few minuets after coating , the paper tab will now allow you to attach a large paper clip, and hang your film to dry. By using a lab base and thin rod clamped horizontally, its easy to hang 12 4x5s to dry! The blow dryer I use is old and weak! But it has two settings hi/low heat, at low it is very weak (blowing), and you will see me blowing close to the wet emulsion. Most new blow dryers will be way to powerful for this. To apply the emulsion I use a simple squirt bottle, very easy to regulate flow, with the current bottle, I can coat three 4x16 plate before I have to recharge the bottle. [http://www.holowiki.com/HoloWiki/images/coatmeth.wmv Dave Battin's Coating Video] (dead link) [http://www.youtube.com/watch?v=b0Toqidt0eo Dave Battin's Coating Video on YouTube] ec8dc6d1636cb12b12fd803c206aaa81c19cdd85 0 589 1329 1328 2013-05-12T02:55:13Z Jsfisher 1 1 revision wikitext text/x-wiki Most Lippmann photographs in museums are covered with a prism to bounce the first surface reflection from the eye. They are also painted black from the back to increase contrast. '''Darran Green writes:''' For daylight viewing select a room with one window through which an unobstructed region of sky can be seen. A hazy white sky or diffuse cloud is preferable to blue, but if blue select the brightest region for illuminating the plate. Stand the plate on a table or shelf, or just hold it at arms length, lower the cover glass to reveal the emulsion side of the plate,and arrange the emulsion side facing the sky and around two meters from the window. Once you see the sky mirrored in the plate you should also see any diffracted colours reconstructed from the image. It isn't absolutely necessary, but you can block out some of the light to reduce effective size of window and improve viewing conditions, as recommended by Ives, an early Lippmann photographer. For viewing by artificial light, black out a room, and use a diffuser such as a 8x10 transparency sleeve mounted in black card matt, arranged about 18" above the plate and a bright halogen spot above the diffuser. Arrange the plate emulsion side up with cover glass lowered, and when you see the diffuser mirrored in the plate the colours should appear. Another thing you could try for a bit of fun, is to find a room in which direct sunlight shines. Allow full sunlight to illuminate emulsion side with cover glass lowered. Using an opaque white card reflect the image onto the card at as close a range as possible without obstructing the projected image and to maintain image sharpness. The image will be laterally reversed. 344e13c5eb254372568bcd839b8656ca6cc8b5a5 0 590 1331 1330 2013-05-12T02:55:14Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Warm colors''' - any colors which, by association, suggest warmth, such as red, orange and yellow. '''Washing''' - the final part of the processing cycle, which removes residual chemicals and soluble silver complexes from the emulsion. '''Water bath''' - large water filled containers used to maintain processing trays, tanks or chemicals at the correct temperature. '''Water softeners''' - used to eliminate most of the minerals and slats found in hard water. '''Watkins factor''' - an old system of development control, based on observation of the processing image under safe lights. '''Watt''' - a unit of power in electricity. '''Watt-second''' - an alternative unit of energy, equal to the joule. '''Wavelength''' - the distance from wave-crest to wave-crest between two corresponding waves of light in the electro-magnetic spectrum. Wavelengths are measured in nanometers (nm) and Angstrom units (A). '''Waxed paper process''' - an early form of photography. A variation on the calotype process. '''Weak''' - a negative or print which is low in contrast or density. '''Wedge spectrogram''' - an indication of the spectral sensitivity of a sensitized material by exposing it to a spectrum of light through a graduated gray wedge. '''Wet collodion''' - a much improved calotype developed by Frederick Scott Archer. A sensitized glass plate was dipped into a bath of silver nitrate and exposed while still wet. The improved speed made much shorter exposures possible. '''Wet processing''' - processing by the application of chemicals in fluid form. The traditional method of photographic processing. '''Wetting agents''' - chemicals which, when used in minute quantities, reduce the surface tension of water. They are usually added to the final wash of films and plates to improve draining. '''White light spectrum''' - the electromagnetic wavelengths between 400-700 nanometers. Also referred to as the visible spectrum. '''Whole plate''' - a negative or print format measuring 6 * x 8 * inches. '''Wide-angle lens''' - a lens with wide covering power. It has a focal length which is less than the diagonal of the film format with which it is being used. '''Wood grain''' - a term for a pattern formed on a hologram by polarized. '''Wood print''' - a print made on a wood surface which has been photochemically prepared. '''Working aperture''' - the widest aperture at which an acceptable image can be achieved. '''Working solution''' - a liquid chemical that has been mixed and diluted for use. e858f830cbc8db77e9c8e62956094fb68ace65e0 0 591 1333 1332 2013-05-12T02:55:14Z Jsfisher 1 1 revision wikitext text/x-wiki Wave plates consist of some birefringent material (like quartz) and modify the [[Polarization]] of a laser beam. Lambda/4 wave plates (also called 1/4 waveplates) turn linearly polarized light into circular polarized light, and as such are not of great use to holographers. Lambda/2 wave plates (also called half-waveplates) rotate the [[Polarization]] of a laser beam by a fixed amount, depending on the orientation of the preferred axis. They thus need to be fixed in a rotation mount. A waveplate is usually only usable at a single frequency, in order to rotate the polarization of a multi-colored laser beam see [[Fresnel Rhomb]]. Lambda/2 wave plates are often used by holographers for the following reasons: *For rotating the polarization of a laser to avoid holograms with superimposed "wood grain" structure. This arises from interference between beams reflected from the front and back sides of a holographic plate. One technique to avoid this is to use [[Index Matching]], but a simpler method is to illuminate the plate by a reference beam at the [[Brewster's Angle]]. When properly polarized, there won't be any reflections and thus, no interference. When the reference beam is tilted horizontally (vertically), then one needs horizontal (vertical) linear polarization of the laser beam. Small lasers like tubular HeNe lasers can simply be rotated to achieve the correct polarization, but this won't work for larger lasers like [[Types_of_Lasers#Argon_Ion_Lasers|argon lasers]], which are usually vertically polarized. For these, a Lambda/2 (half-wave) waveplate can be used to rotate the polarization appropriately. *For rotating the polarization of the reference with respect the polarization of the object beam, to maximize image contrast or to achieve special effects. If you put a polarizer at the film plane aligned to the polarization of the unaltered object beam so you can see the reflections and place a 1/2 wave plate in the object beam you will see the relative brightness of the reflections dim as you rotate the polarization off axis. Rotate the 1/2 wave plate so the reflections and the diffuse light from the object have the "desired" brightness. Also, make sure that any bright spot is not exactly on the film plane when making an H2 or it will burn out. *In conjunction with a [[Holography_Technology#Cube_Beamsplitters|polarizing cube beam splitter]], a pair of Lambda/2 plates is the best method to split a laser beam into two beams with a variable beam ratio. Wave plates are usually quite wavelength dependent and will work well only very close to their design wavelength. Multi-order waveplate are more wavelength sensitive than zero-order wave plates. There exist however broad band wave plates as well. Usually wave plates are expensive and not too often available as surplus - if you see one, get it! For the hobbyist, there are also the following two options: *If she happens to have a few waveplates designed for other wavelengths than the desired one, try to mount them in tandem and play with their relative orientations: there is often a spot where a linear rotation can be achieved. Even using Lambda/4 wave plates can sometimes work in this way. Another reason to catch any conceivable wave plate on ebay! *LCD screens from old electronic pocket games (in particular Nintendo types from the early 80's) sometimes can be used as broad band Lambda/2 wave plates. This needs to be tried case-by-case. The relevant piece is the top glass plate that needs to be taken off. The disadvantage is often poor optical quality (can be remedied by a [[Holography_Technology#Spatial_Filters|spatial filter]]), and interferences from front and back sides that lead to an uneven illumination. Commercial wave plates are usually anti-reflection coated and so avoid this problem. *Stacks of Seran Wrap can also be stacked to the right thickness for a quick and dirty wave plate. *If you take a piece of mica and flake a few flakes off one may be the right thickness to be a multiorder wave plate. This is another quick and dirty method. 336dffb7800a6bbffb331dc684083a8b6848004d 0 592 1335 1334 2013-05-12T02:55:14Z Jsfisher 1 1 revision wikitext text/x-wiki What is Art? by Leo Tolstoy CHAPTER FIVE (excerpts) . . . 1. In order correctly to define art, it is necessary, first of all, to cease to consider it as a means to pleasure and to consider it as one of the conditions of human life. Viewing it in this way we cannot fail to observe that art is one of the means of intercourse between man and man. 2. Every work of art causes the receiver to enter into a certain kind of relationship both with him who produced, or is producing, the art, and with all those who, simultaneously, previously, or subsequently, receive the same artistic impression. 3. Speech, transmitting the thoughts and experiences of men, serves as a means of union among them, and art acts in a similar manner. The peculiarity of this latter means of intercourse, distinguishing it from intercourse by means of words, consists in this, that whereas by words a man transmits his thoughts to another, by means of art he transmits his feelings. 4. The activity of art is based on the fact that a man, receiving through his sense of hearing or sight another man's expression of feeling, is capable of experiencing the emotion which moved the man who expressed it. To take the simplest example; one man laughs, and another who hears becomes merry; or a man weeps, and another who hears feels sorrow. A man is excited or irritated, and another man seeing him comes to a similar state of mind. By his movements or by the sounds of his voice, a man expresses courage and determination or sadness and calmness, and this state of mind passes on to others. A man suffers, expressing his sufferings by groans and spasms, and this suffering transmits itself to other people; a man expresses his feeling of admiration, devotion, fear, respect, or love to certain objects, persons, or phenomena, and others are infected by the same feelings of admiration, devotion, fear, respect, or love to the same objects, persons, and phenomena. 5. And it is upon this capacity of man to receive another man's expression of feeling and experience those feelings himself, that the activity of art is based. 6. If a man infects another or others directly, immediately, by his appearance or by the sounds he gives vent to at the very time he experiences the feeling; if he causes another man to yawn when he himself cannot help yawning, or to laugh or cry when he himself is obliged to laugh or cry, or to suffer when he himself is suffering - that does not amount to art. 7. Art begins when one person, with the object of joining another or others to himself in one and the same feeling, expresses that feeling by certain external indications. To take the simplest example: a boy, having experienced, let us say, fear on encountering a wolf, relates that encounter; and, in order to evoke in others the feeling he has experienced, describes himself, his condition before the encounter, the surroundings, the woods, his own lightheartedness, and then the wolf's appearance, its movements, the distance between himself and the wolf, etc. All this, if only the boy, when telling the story, again experiences the feelings he had lived through and infects the hearers and compels them to feel what the narrator had experienced is art. If even the boy had not seen a wolf but had frequently been afraid of one, and if, wishing to evoke in others the fear he had felt, he invented an encounter with a wolf and recounted it so as to make his hearers share the feelings he experienced when he feared the world, that also would be art. And just in the same way it is art if a man, having experienced either the fear of suffering or the attraction of enjoyment (whether in reality or in imagination) expresses these feelings on canvas or in marble so that others are infected by them. And it is also art if a man feels or imagines to himself feelings of delight, gladness, sorrow, despair, courage, or despondency and the transition from one to another of these feelings, and expresses these feelings by sounds so that the hearers are infected by them and experience them as they were experienced by the composer. 8. The feelings with which the artist infects others may be most various - very strong or very weak, very important or very insignificant, very bad or very good: feelings of love for one's own country, self-devotion and submission to fate or to God expressed in a drama, raptures of lovers described in a novel, feelings of voluptuousness expressed in a picture, courage expressed in a triumphal march, merriment evoked by a dance, humor evoked by a funny story, the feeling of quietness transmitted by an evening landscape or by a lullaby, or the feeling of admiration evoked by a beautiful arabesque - it is all art. 9. If only the spectators or auditors are infected by the feelings which the author has felt, it is art. 10. To evoke in oneself a feeling one has once experienced, and having evoked it in oneself, then, by means of movements, lines, colors, sounds, or forms expressed in words, so to transmit that feeling that others may experience the same feeling - this is the activity of art. 11. Art is a human activity consisting in this, that one man consciously, by means of certain external signs, hands on to others feelings he has lived through, and that other people are infected by these feelings and also experience them. 12. Art is not, as the metaphysicians say, the manifestation of some mysterious idea of beauty or God; it is not, as the aesthetical physiologists say, a game in which man lets off his excess of stored-up energy; it is not the expression of man's emotions by external signs; it is not the production of pleasing objects; and, above all, it is not pleasure; but it is a means of union among men, joining them together in the same feelings, and indispensable for the life and progress toward well-being of individuals and of humanity. 13. As, thanks to man's capacity to express thoughts by words, every man may know all that has been done for him in the realms of thought by all humanity before his day, and can in the present, thanks to this capacity to understand the thoughts of others, become a sharer in their activity and can himself hand on to his contemporaries and descendants the thoughts he has assimilated from others, as well as those which have arisen within himself; so, thanks to man's capacity to be infected with the feelings of others by means of art, all that is being lived through by his contemporaries is accessible to him, as well as the feelings experienced by men thousands of years ago, and he has also the possibility of transmitting his own feelings to others. 14. If people lacked this capacity to receive the thoughts conceived by the men who preceded them and to pass on to others their own thoughts, men would be like wild beasts, or like Kaspar Houser. 15. And if men lacked this other capacity of being infected by art, people might be almost more savage still, and, above all, more separated from, and more hostile to, one another. 16. And therefore the activity of art is a most important one, as important as the activity of speech itself and as generally diffused. 17. We are accustomed to understand art to be only what we hear and see in theaters, concerts, and exhibitions, together with buildings, statues, poems, novels. . . . But all this is but the smallest part of the art by which we communicate with each other in life. All human life is filled with works of art of every kind - from cradlesong, jest, mimicry, the ornamentation of houses, dress, and utensils, up to church services, buildings, monuments, and triumphal processions. It is all artistic activity. So that by art, in the limited sense of the word, we do not mean all human activity transmitting feelings, but only that part which we for some reason select from it and to which we attach special importance. 18. This special importance has always been given by all men to that part of this activity which transmits feelings flowing from their religious perception, and this small part of art they have specifically called art, attaching to it the full meaning of the word. 19. That was how man of old -- Socrates, Plato, and Aristotle - looked on art. Thus did the Hebrew prophets and the ancient Christians regard art; thus it was, and still is, understood by the Mohammedans, and thus it still is understood by religious folk among our own peasantry. 20. Some teachers of mankind - as Plato in his Republic and people such as the primitive Christians, the strict Mohammedans, and the Buddhists -- have gone so far as to repudiate all art. 21. People viewing art in this way (in contradiction to the prevalent view of today which regards any art as good if only it affords pleasure) considered, and consider, that art (as contrasted with speech, which need not be listened to) is so highly dangerous in its power to infect people against their wills that mankind will lose far less by banishing all art than by tolerating each and every art. 22. Evidently such people were wrong in repudiating all art, for they denied that which cannot be denied - one of the indispensable means of communication, without which mankind could not exist. But not less wrong are the people of civilized European society of our class and day in favoring any art if it but serves beauty, i.e., gives people pleasure. 23. Formerly people feared lest among the works of art there might chance to be some causing corruption, and they prohibited art altogether. Now they only fear lest they should be deprived of any enjoyment art can afford, and patronize any art. And I think the last error is much grosser than the first and that its consequences are far more harmful. CHAPTER FIFTEEN 24. Art, in our society, has been so perverted that not only has bad art come to be considered good, but even the very perception of what art really is has been lost. In order to be able to speak about the art of our society, it is, therefore, first of all necessary to distinguish art from counterfeit art. 25. There is one indubitable indication distinguishing real art from its counterfeit, namely, the infectiousness of art. If a man, without exercising effort and without altering his standpoint on reading, hearing, or seeing another man's work, experiences a mental condition which unites him with that man and with other people who also partake of that work of art, then the object evoking that condition is a work of art. And however poetical, realistic, effectful, or interesting a work may be, it is not a work of art if it does not evoke that feeling (quite distinct from all other feelings) of joy and of spiritual union with another (the author) and with others (those who are also infected by it). 26. It is true that this indication is an internal one, and that there are people who have forgotten what the action of real art is, who expect something else form art (in our society the great majority are in this state), and that therefore such people may mistake for this aesthetic feeling the feeling of diversion and a certain excitement which they receive from counterfeits of art. But though it is impossible to undeceive these people, just as it is impossible to convince a man suffering from "Daltonism" [a type of color blindness] that green is not red, yet, for all that, this indication remains perfectly definite to those whose feeling for art is neither perverted nor atrophied, and it clearly distinguishes the feeling produced by art from all other feelings. 27. The chief peculiarity of this feeling is that the receiver of a true artistic impression is so united to the artist that he feels as if the work were his own and not someone else's - as if what it expresses were just what he had long been wishing to express. A real work of art destroys, in the consciousness of the receiver, the separation between himself and the artist - not that alone, but also between himself and all whose minds receive this work of art. In this freeing of our personality from its separation and isolation, in this uniting of it with others, lies the chief characteristic and the great attractive force of art. 28. If a man is infected by the author's condition of soul, if he feels this emotion and this union with others, then the object which has effected this is art; but if there be no such infection, if there be not this union with the author and with others who are moved by the same work - then it is not art. And not only is infection a sure sign of art, but the degree of infectiousness is also the sole measure of excellence in art. 29. The stronger the infection, the better is the art as art, speaking now apart from its subject matter, i.e., not considering the quality of the feelings it transmits. 30. And the degree of the infectiousness of art depends on three conditions: On the greater or lesser individuality of the feeling transmitted; on the greater or lesser clearness with which the feeling is transmitted; on the sincerity of the artist, i.e., on the greater or lesser force with which the artist himself feels the emotion he transmits. 31. The more individual the feeling transmitted the more strongly does it act on the receiver; the more individual the state of soul into which he is transferred, the more pleasure does the receiver obtain, and therefore the more readily and strongly does he join in it. 32. The clearness of expression assists infection because the receiver, who mingles in consciousness with the author, is the better satisfied the more clearly the feeling is transmitted, which, as it seems to him, he has long known and felt, and for which he has only now found expression. 33. But most of all is the degree of infectiousness of art increased by the degree of sincerity in the artist. As soon as the spectator, hearer, or reader feels that the artist is infected by his own production, and writes, sings, or plays for himself, and not merely to act on others, this mental condition of the artist infects the receiver; and contrariwise, as soon as the spectator, reader, or hearer feels that the author is not writing, singing, or playing for his own satisfaction - does not himself feel what he wishes to express - but is doing it for him, the receiver, a resistance immediately springs up, and the most individual and the newest feelings and the cleverest technique not only fail to produce any infection but actually repel. 34. I have mentioned three conditions of contagiousness in art, but they may be all summed up into one, the last, sincerity, i.e., that the artist should be impelled by an inner need to express his feeling. That condition includes the first; for if the artist is sincere he will express the feeling as he experienced it. And as each man is different from everyone else, his feeling will be individual for everyone else; and the more individual it is - the more the artist has drawn it from the depths of his nature - the more sympathetic and sincere will it be. And this same sincerity will impel the artist to find a clear expression of the feeling which he wishes to transmit. 35. Therefore this third condition - sincerity - is the most important of the three. It is always complied with in peasant art, and this explains why such art always acts so powerfully; but it is a condition almost entirely absent from our upper-class art, which is continually produced by artists actuated by personal aims of covetousness or vanity. 36. Such are the three conditions which divide art from its counterfeits, and which also decide the quality of every work of art apart from its subject matter. 37. The absence of any one of these conditions excludes a work form the category of art and relegates it to that of art's counterfeits. If the work does not transmit the artist's peculiarity of feeling and is therefore not individual, if it is unintelligibly expressed, or if it has not proceeded from the author's inner need for expression - it is not a work of art. If all these conditions are present, even in the smallest degree, then the work, even if a weak one, is yet a work of art. 38. The presence in various degrees of these three conditions - individuality, clearness, and sincerity - decides the merit of a work of art as art, apart from subject matter. All works of art take rank of merit according to the degree in which they fulfill the first, the second, and the third of these conditions. In one the individuality of the feeling transmitted may predominate; in another, clearness of expression; in a third, sincerity; while a fourth may have sincerity and individuality but be deficient in clearness; a fifth, individuality and clearness but less sincerity; and so forth, in all possible degrees and combinations. 39. Thus is art divided from that which is not art, and thus is the quality of art as art decided, independently of its subject matter, i.e., apart from whether the feelings it transmits are good or bad. 40. But how are we to define good and bad art with reference to its subject matter? 551d11cf1ff62a624b5ad3c1a5205c16f72f6127 0 593 1337 1336 2013-05-12T02:55:14Z Jsfisher 1 1 revision wikitext text/x-wiki A Wiki is really a large scratch pad that is edited by a collective. Wikis can be completely public or completely private. The HoloWiki can be viewed by all but only edited by registered users. At any time any page on a Wiki can be edited by any user. The software logs all edits and an editor can look back to older revisions in order to save deleted information or have it for reference during an edit. The word Wiki is from the Hawiian language where wiki wiki means quickly. Feel free to edit any page that is not an author specific article. Any author specific articles should have comments put into the discussion link at the top of the page. This will allow the author to make the edits. This is a professional courtesy to our authors that have spent considerable time writing an article. Also, I intend to have the biographies be a place where a holographer represents themselves. Please do not use them to review their work. If we need a place to review work we can make a new section. d777603bcdfd280e28d122be22972a66c71dbd8b 0 594 1339 1338 2013-05-12T02:55:15Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Xenon''' - a rare gas sometimes used with electronic flash tubes and enclosed arc light sources. '''Xerography''' - a photographic process which uses an electrically charged metal plate. On exposure to light the electrical charge is destroyed, leaving a latent image in which shadows are represented by charged areas. A powdered pigment dusted over the plate is attracted to the charged areas, producing a visible image. '''Xography''' - a system of photography which produces prints and transparencies with a three-dimensional effect. A cylindrically embossed lenticular screen is placed in contact with the film and a shutter behind the lens is arranged to scan the subject during exposure. '''X ray''' - electromagnetic radiations beyond ultraviolet which, when passed through a solid object and allowed to act upon a sensitive emulsion, form a shadow image of the internal structure of the object. '''X ray film''' - spectral sheet film for radiography, having a thick emulsion coated on both sides of the support to increase the absorption of X rays. 0184618011cfa25c041078dedd96336ab2911dec 0 595 1341 1340 2013-05-12T02:55:15Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- 744390aabe168f30877c11535c648a5b6e16d923 0 596 1343 1342 2013-05-12T02:55:15Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:YDenisyuk.jpg]] Died at the age of 88 in May 2006. Yuri Denisyuk invented single beam reflection holography. ===A Memorial by Ed Wesley=== {| |[[Image:YDenisyuk2.jpg]]|| “Now maybe the girls will notice me!” quips Yuri Denisyuk, proudly displaying the Cyrillic Danger: Laser Radiation sign presented to him by the local Coherent Laser sales rep at his first visit to Lake Forest College in 1989. This is my favorite image of one the great gods of Mt. Holympus, personified as everyone’s favorite grandfather with a wacky sense of humor. After all, it was a science fiction story that inspired him to invent his own style of wavefront reconstruction! |} 23547694fa01e4436246f818676e4a704e37c097 0 597 1345 1344 2013-05-12T02:55:15Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.ultimate-holography.com/ Ultimate] f53c72dd5cf18f75124dee086093de3f6f579631 0 598 1347 1346 2013-05-12T02:55:16Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- '''Zirconium lamp''' - an arc lamp used in powerful enlarges and projectors. '''Zoetrope''' - an early device for creating illusion of continuous motion. A sequence of still pictures was viewed so quickly through slits in a rotating drum, that the images appeared to merge. '''Zone focusing''' - a method of focusing the lens so that the depth of field extends over a preselected range of distances. '''Zone system''' - the method of determining exposure and development required for individual scenes, invented by Ansel Adams. It is based on analysis of subject luminosities in terms of ten gray tones, labeled zones 0 through X and previsualizing them as print densities. By measuring each subject luminance with a hand meter it is possible to determine how much the range of values must be contracted or expanded by negative development control to give the required values in the print. c39458c550c1f325a404637ef446171f7e2f6b1d 0 1 1348 156 2013-05-12T03:00:58Z Jsfisher 1 wikitext text/x-wiki Welcome to the [http://www.holographyforum.org Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms. </p> <ul><li><b><a href="/index.php?title=Abbreviations" title="Abbreviations">Abbreviations</a>.</b> Commonly used abbreviations by holographers. </li><li><b><a href="/index.php?title=Holography_for_Beginners" title="Holography for Beginners">Holography for Beginners</a>.</b> A FAQ for beginning holographers. </li><li><b><a href="/index.php?title=Holography_Technology" title="Holography Technology">Holography Technology</a>.</b> The hardware and setups for making holograms. </li><li><b><a href="/index.php?title=Hologram_Recording_Materials" title="Hologram Recording Materials">Hologram Recording Materials</a>.</b> How to get, make and use them and chemistry. </li><li><b><a href="/index.php?title=Holography_Theory" title="Holography Theory">Holography Theory</a>.</b> The Mathematics and Science of Holography. </li><li><b><a href="/index.php?title=History_of_Holography" title="History of Holography">History of Holography</a>.</b> The timeline of the people and technology. </li><li><b><a href="/index.php?title=Holography_Safety" title="Holography Safety">Holography Safety</a>.</b> Chemical and laser safety. A must read! </li><li><b><a href="/index.php?title=Biographies_of_Holographers" title="Biographies of Holographers">Biographies of Holographers</a>.</b> The people who have made it all possible. </li><li><b><a href="/index.php?title=Holography_Links" title="Holography Links">Holography Links</a>.</b> Other resources for holographers on the web. </li><li><b><a href="/index.php?title=Holography_Glossary" title="Holography Glossary">Holography Glossary</a>.</b> Holography technical terms defined. </li></ul> <p><a href="/index.php?title=Archives" title="Archives">Archives</a> </p> <!-- Saved in parser cache with key holowiki_1357asdf:pcache:idhash:1-0!1!0!!en!2!edit=0 and timestamp 20120601085004 --> <div class="printfooter"> Retrieved from "<a href="http://www.holowiki.org/index.php?title=Main_Page">http://www.holowiki.org/index.php?title=Main_Page</a>"</div> <!-- end content --> <div class="visualClear"></div> </div> </div> </div> <div id="column-one"> <div id="p-cactions" class="portlet"> <h5>Views</h5> <div class="pBody"> <ul> <li id="ca-nstab-main" class="selected"><a href="/index.php?title=Main_Page" title="View the content page [c]" accesskey="c">Article</a></li> <li id="ca-talk"><a href="/index.php?title=Talk:Main_Page" title="Discussion about the content page [t]" accesskey="t">Discussion</a></li> <li id="ca-viewsource"><a href="/index.php?title=Main_Page&amp;action=edit" title="This page is protected. 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Commonly used abbreviations by holographers. * [[Holography for Beginners | '''Holography for Beginners''']]. An FAQ for beginning holographers. * [[Holography Technology | '''Holography Technology''']]. The hardware and setups for making holograms. * [[Hologram Recording Materials | '''Hologram Recording Materials''']]. How to get, make and use them and chemistry. * [[Holography Theory | '''Holography Theory''']]. The Mathematics and Science of Holography. * [[History of Holography | '''History of Holography''']]. The timeline of the people and technology. * [[Holography Safety | '''Holography Safety''']]. Chemical and laser safety. A must read! * [[Biographies of Holographers | '''Biographies of Holographers''']]. The people who have made it all possible. * [[Holography Links | '''Holography Links''']]. Other resources for holographers on the web. * [[Holography Glossary | '''Holography Glossary''']]. Holography technical terms defined. * [[Archives | '''Archives''']]. ba1885126b81eca80a165938aa116099c64399ac 6 599 1350 2013-05-12T04:02:56Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 600 1351 2013-05-12T04:02:57Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 601 1352 2013-05-12T04:02:58Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 602 1353 2013-05-12T04:02:59Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 603 1354 2013-05-12T04:03:00Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 605 1356 2013-05-12T04:03:02Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 606 1357 2013-05-12T04:03:03Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 607 1358 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2013-05-12T04:06:34Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 799 1550 2013-05-12T04:06:36Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 800 1551 2013-05-12T04:06:37Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 801 1552 2013-05-12T04:06:38Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 802 1553 2013-05-12T04:06:39Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 803 1555 1554 2013-05-12T04:07:48Z Jsfisher 1 1 revision wikitext text/x-wiki [[Category:Rallison]] [[Category:DCG]] == 2 and 3 Color Dichromates, Production Method == The two color method produces rich Red-Orange and bright clean Blue-Green colors that mix to a creamy white. Color coding of the object is optional but helpful in most cases and production is done from two masters in two different films. The three color system requires color coding for Red at the mastering stage but no coding for Blue or Green, which are mastered first. Both systems are part natural, part pseudo color and require only two laser lines and two film formulations. Blue is obtained naturally by using the 458 argon line and Green or Red are derived from the 514 line. In production the two color system is identical to current master/copy methods in that batches are shot at 458 or at 514 and later registered and laminated together. The three color system requires Blue and Green exposures in the same emulsion and Red in a second batch. The laser must then be operated multiline or be switched constantly or a second laser introduced. The preferred method is multiline operation with independent shuttering. The two color system makes very satisfying flesh tones and color balance is fairly easy to maintain because it can be done by mixing and matching batches and or individual holograms at the laminating stage.Object preparation is as follows, Blue-Green areas should be overcoated lightly with a bright blue pigment such as Liquitex Brilliant Blue #20002-381 or Pelikan Deep Blue #39. This will effectively inhibit reflection at 514. The Red-Orange areas must be touched up with Yellow pigment such as Liquitex #1002-411 or Pelikan Yellow #10 both of which absorb 458 but reflect 514. At this stage H1 masters or correctly colored copies can be made, the Blue-Green master may be made to reconstruct at 488 so that production copies can be done using only 488 and 514. The 514 exposure is done with the film side facing the reference beam and the 458 exposure is done the other way around with a spacer between the object and film having the same optical thickness as the 514 substrate. Formulas for each film and processing details are as follows. <font color="#FF0000">Red-</font>- mix 3-30-250 using Potassium Dichromate spin on at 80-90 RPM, expose single beam 90-100 mj\cmE2 @ 514 if RH = 60% and T = 70 F. Process: develop 5 min., rinse, 30 sec in 1HAB @ 120 F and .86 SG. Dry with slow pull from LHAB followed by hot air. Color should be bright Red-Orange. <font color="#1A1AFF">Blue-</font>-Mix 9-30-250 using Ammonium Dichromate, spin on at 80-90 RPM, expose single beam 24 mj\cmE2 @ 458 if RH = 60% and T = 70 F. Process: develop 3 min., rinse, 15 sec in 1HAB @ 120 F and .86 SG. Dry with slow pull, color should be bright Blue to Blue-Green. This film was 2-4 hrs old, shorten times for older film. For 3 Color system use 10-30-250 and expose twice, once with 24 mj @ 458 and once with 50 mj @ 514. Then code the object for Red and use the same red procedure. <br> (This paper was used for a class at Lake Forest College and was never published as is. The same information has been published in SPIE Vol 1600 mostly on page 35.) 554ac788a729ee611ae3b013f679c3664d6a7dc4 0 155 1557 158 2013-05-12T04:07:48Z Jsfisher 1 1 revision wikitext text/x-wiki == Biological Basis of Vision == ===The Human Eye=== Well-informed expositions on the biology and architecture of the human eye are available online, for example: [http://www.merck.com/mmhe/sec20/ch224/ch224b.html Online Merck Manual]. A broad article is available at [http://en.wikipedia.org/wiki/Eye WikiPedia]. A frequently cited reference on the retina from a neural/functional standpoint is Dowling (1987). The human eye is a direct extension of the brain; much more than a "biological camera," the eye performs pre-computation on observed imagery prior to transmitting it towards the visual cortex. In the words of Churchland and Sejnowski (1993), "[t]he primate retina transforms patterns of light on the 100 million photoreceptors into electrical signals on the mere one million axons in the optic nerve, and the 100:1 compression ratio suggests heavy-duty signal processing and information compression" (p. 148). One striking illusion that highlights visual precomputation, [http://studenthome.nku.edu/%7Edouglask/illusions/MachBands.htm Mach banding], is the incorrectly-perceived brightness at edges of differently-shaded fields. Although still incompletely understood, this may be due to lateral inhibition amongst nearby photoreceptors, resulting in high-pass filtering in the eye itself. ===Relevant Neural Regions=== In general, imagery from the right visual field (as collected by the ''left'' hemisphere of both eyes) is transmitted via the optic nerve and optic chiasm to the left hemisphere's optic tract; likewise, imagery from the left visual field travels along the ''right'' hemisphere's optic tract. We note that most of this flows to the thalamus's lateral geniculate nucleus (LGN), with another pathway to the superior colliculus. The information reaches the visual cortex, which is located at the back of the brain. The visual cortex has several regions: V1, V2, and so on, whose supposed function is beyond the scope of this discussion. However, we note two relevant and generally-supported hypotheses: '''Retinotopic Mapping in V1''' A striking series of experiments showed that regions of the visual cortex are mapped retinotopically to the observed field, that is, "neighboring cells have neighboring receptive fields" (Churchland & Sejnowski, 1994, p. 155). In a seminal experiment performed by Roger Tootell, a primate's brain was examined after fixation on a patterned bullseye-like target - when the brain was stained as a function of activity, an image of the target was clearly visible on the unfolded cortex (Tootell, Silverman, Switkes & De Valois, 1982). See a [http://neuro.med.harvard.edu/site/dh/114.jpg photograph here], from the Harvard website containing David Hubel's online vision textbook. [http://neuro.med.harvard.edu/site/dh/b23.htm section: The Architecture of the Visual Cortex.] '''Regions of V1 and V2 Correspond to Varying Degrees of Monocularity and Binocularity''' Churchland and Sejnowski (1994) state that: "For the brain to generate stereo vision, there must be means for the brain to compare retinal images ''relative to varying planes of fixation.'' Hubel and Wiesel (1963) discovered that striate cortical cells were not uniform in their response to a visual stimulus, but some cells were strongly monocular, and were flanked by other cells responding somewhat to stimuli from both eyes, though preferring one or the other, flanked in turn by cells that were binocular" (p. 197). See David Hubel's [http://nobelprize.org/medicine/laureates/1981/hubel-lecture.pdf 1981 Nobel Prize lecture]. Learn more about the visual cortex at [http://en.wikipedia.org/wiki/Visual_cortex Wikipedia]. == Depth Cues == Humans perceive imagery that falls on their retina(s) as three-dimensional when influenced by one or more ''depth cues.'' Monocular depth cues can be experienced with just one eye; binocular depth cues require two. === Monocular Depth Cues === Briefly, monocular depth cues include: *'''Relative size:''' larger objects are interpreted as being nearer the observer *'''Interposition / Overlapping:''' close objects tend to occlude far objects *'''Linear perspective (foreshortening):''' Receding parallel lines appear to meet at the horizon. *'''Aerial perspective (haze / fog):''' Blurry or foggy objects may be interpreted as distant, since haze usually blurs distant scene elements. *'''Light and shade:''' So-called "2 1/2-D" rendering uses the interplay of shape and light to suggest the three-dimensionality of objects. Note that people assume that light comes from above when viewing an image; this is the so-called ''light-from-above prior'' or ''light-from-above heuristic''. *'''Motion parallax:''' Horizontal observer movement (egomotion) "makes" near objects appear to move faster than distant objects. Note that this cue can be used to simulate egomotion, that is, in movies, animations, and true 3-D representations, moving foreground elements faster than background elements evokes the sensation of movement. *'''Accommodation (focus):''' Retinal focus provides information to your brain about the probable distance from your eye to the object you are fixating on. One issue of non-holographic 3-D displays is the so-called "accommodation / vergence conflict," in which the angular swivel of the eyes does not agree with their focus. This happens, for example, when watching a stereoscopic 3-D movie, since there are cases in which your eyes are focused at a distant screen while they are rotated inwards to gaze at a very close scene element. *'''Texture Gradient:''' As in a field of wheat, the perception of a textured region is a function of distance. A variety of [http://www.sapdesignguild.org/resources/optical_illusions/index.html optical illusions] prey upon the assumptions your mind makes about interpreting monocular depth cues. ===Binocular Depth Cues (Stereopsis)=== The average interpupillary distance is approximately 6-6.5 cm. In normal circumstances, this leads to each eye observing a different 2-D field. The brain interprets these differences for depth information, such as (De Valois & De Valois, 1990): *'''Vergence:''' The angular "swivel" of the eyes while gazing at an object provides a strong cue regarding the depth of that object. *'''Positional Disparity:''' A large-scale illustration of positional disparity is observed by holding one's outstretched index finger and observing the relative motion of your finger and the background when viewed alternately by your left and right eyes. [http://en.wikipedia.org/wiki/Stereopsis Wikipedia: Stereopsis] *'''Phase Disparity of Frequency Components:''' There is evidence suggesting that the brain is sensitive to the phase difference of the frequency components of an image, which has a different magnitude, of course, than displacing the sine wave component itself (De Valois & De Valois, 1990, p. 302) *'''Orientation Disparity:''' Orientation disparity refers, for example, to the different angle a line makes on each retina when gazing at a line pitched toward or away from the observer. *'''Spatial Frequency Disparity:''' The separable existence of this cue may still be in debate. Spatial frequency disparity is the difference in spatial frequency for scene elements that are, for example, at varying depths from the observer (Halpern et al, 1987). For example, pitching a single-frequency grating at an angle to the observer yields different perceived spatial frequencies in each eye (De Valois & De Valois, 1990, p. 307). The collection of potential disparities are called ''stereopsis.'' '''An Implication of Random-dot Stereograms''' Note that the brain does not require local stereopsis to perceive depth; global stereopsis "can occur without monocular contours" (De Valois & De Valois, 1990, p. 314). For example, Julesz's (1971) random-dot stereograms present two views that appear, in a monocular sense, like disorganized spatial noise. However, the brain is able to fuse the two images into a scene containing depth - perhaps via the global low-freqency content in the imagery. ==Guidelines for Effective 3-D Imagery== ===Rules of Thumb for Particular Display Media=== One implication of the preceding discussion is that it is best to match subject matter to the display medium and intended observation environment. Experts in the following media are invited to add their own rules of thumb: * Holographic stereograms * Cylindrical multiplex holograms * Quasi-holographic electro-optical displays ===Bandlimiting Can Decrease Interview Aliasing=== Holographic stereograms and other discrete-"view" 3-D displays can exhibit motion artifacts due to interview aliasing. For example, image points far from the image surface appear to jump to neighboring views during egomotion if they are sampled or reconstructed improperly. Holography researcher Michael Halle (1994) discusses these constraints, which apply in particular to holographic stereograms and non-holographic parallax displays. In short, interview aliasing can be mitigated by intentionally blurring scene elements distant from the image surface. ===Understand Your Medium's Focus Characteristics=== Of course, different 3-D display media use different methods to reconstruct 3-D light fields. For example, some holograms are highly astigmatic, putting the horizontal and vertical foci at very different surfaces in or beyond the 3-D scene. The family of horizontal parallax only (HPO) holograms discards some or all vertical parallax information (De Bitetto, 1968; Benton, 1969; De Bitetto, 1969; Benton, 1977). The long-term effects of viewing astigmatic display media, such as HPO holograms, are not widely known in the display community, and references to thoughtful work in the area are appreciated. While not holographic, the variety of electronic 3-D display technologies also vary in their focus characteristics. They range from volumetric displays, whose true voxels in (''x'', ''y'', ''z'') space elicit proper vergence and accommodation cues (Favalora et al, 2005) to experimental "highly-multiview" HPO systems (Favalora, 2005) and lenticular-sheet displays which are HPO ''and'' typically project very discrete infrequently sampled horizonal parallax information. Members of the former MIT Media Laboratory's Spatial Imaging Group explore the importance of choosing the correct scene-sampling and reconstruction geometries as a function of factors including the intended observation point and propose computational predistortion methods for dealing with these issues (Halle, Benton, Klug, & Underkoffler, 1991). == References == <small> *Churchland, P. & Sejnowski, T. J. (1994). ''The Computational Brain''. Cambridge, Mass.:The MIT Press. ISBN 0262531208 *Benton, S. A. (1969). Hologram Reconstructions with Extended Light Sources, ''J. Opt. Soc. Amer. 59'', 1545A. *Benton, S. A. (1977). White-light transmission/reflection holographic imaging. In E. Marom, A. Friesem, & E. Wiener-Avnear (Eds.), ''Applications of Holography and Optical Data Processing'' (pp. 401-409). *De Bitetto, D. J. (1968, March 1). Bandwidth reduction of hologram transmission systems by elimination of vertical parallax. ''Applied Physics Letters, 12''(5), 176-178. *De Bitetto, D. J. (1969, August). Holographic Panoramic Stereograms Synthesized from White Light Recordings. ''Applied Optics, 8''(8), 1740-1741. *De Valois, R. L. & De Valois, K. K. (1990). ''Spatial Vision''. Oxford: Oxford University Press. ISBN 0195050193 *Dowling, J. E. (1987). ''The Retina: An Approachable Part of the Brain''. Cambridge, MA: Harvard University Press (Belknap Press?). ISBN 0674766806 *Favalora, G. E. (2005, August). Volumetric 3D Displays and Application Infrastructure. ''Computer, 38''(8), 37-44. [http://www.greggandjenny.com/gregg/IEEE_Computer_Favalora.pdf PDF] *Favalora, G. E., Chun, W., Cossairt, O. S., Dorval, R. K., Halle, M., Napoli, J., & Thomas, M. (2005), "Scanning optical devices and systems," U.S. Pat. App. US2005/0285027A1, filed Feb. 15. *Halle, M. W., Benton, S. A., Klug, M. A., & Underkoffler, J. S. (1991). The Ultragram: A Generalized Holographic Stereogram. In S. A. Benton (Ed.), ''Practical Holography V'' [Proc. SPIE-IS&T Electronic Imaging, SPIE Vol. 1461] (pp. 142-155). [http://citeseer.ist.psu.edu/halle91ultragram.html CiteSeer] *Halle, M. (1994). Holographic stereograms as discrete imaging systems. In S.A. Benton (Ed.), ''Practical Holography VIII'' [Proc. SPIE] Vol 2176, (pp. 73-84). Bellingham, WA. [http://splweb.bwh.harvard.edu:8000/pages/ppl/halazar/pubs/discrete_spie94_preprint.pdf Preprint PDF] *Halle, M. (1997, May). Autostereoscopic displays and computer graphics. ''Computer Graphics,'' ACM SIGGRAPH, 31(2), 58-62. [http://web.media.mit.edu/~halazar/autostereo/autostereo.html HTML and PDF versions.] *Halpern, D. L. et al (1987). What causes stereoscopic tilt from spatial frequency disparity. ''Vision Res., 27''(9), 1619-1629. *Hubel, D. H. & Wiesel, T. N. (1963). Shape and arrangement of columns in cat's striate cortex. ''Journal of Physiology, 165'', 559-568. *Julesz, B. (1971). ''Foundation of cyclopean perception''. Chicago: University of Chicago Press. *Okoshi, T. (1976). ''Three-Dimensional Imaging Techniques''. Academic Press. ISBN 0-12-525250-1 *Ratliff, F., Milkman, N., & Rennert, N. (1983). Attenuation of Mach bands by adjacent stimuli. ''Proc Natl Acad Sci U S A 80''(14), 4554-8. [http://radiology.rsnajnls.org/cgi/ijlink?linkType=ABST&journalCode=pnas&resid=80/14/4554 Abstract and Article PDF] *Shepherd, G. M. (2003). ''The Synaptic Organization of the Brain''. Oxford University Press. ISBN 019515956X *Tootell, R. B. H., Silverman, M. S., Switkes, E., & De Valois, R. L. (1982). Deoxyglucose analysis of retinotopic organization in primate striate cortex. ''Science, 218'', 902-904. </small> == External Links == * H. Kolb et al, ''[http://webvision.med.utah.edu/ Webvision: The Organization of the Retina and Visual System]'', John Morgan Eye Center, University of Utah (accessed 28 May 2006) * [http://www-staff.lboro.ac.uk/~mmtw/holopaperWeb.pdf Brief Survey on Three-Dimensional Displays: from Our Eyes to Electronic Hologram] 0d0184f021073a6f8b834fb259c5e1a9a0abd0cc 0 156 1559 160 2013-05-12T04:07:48Z Jsfisher 1 1 revision wikitext text/x-wiki ==Holography Glossary== [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Aerial perspective''' - the distance or depth effect caused by atmospheric haze. Haze creates a large amount of extraneous ultra-violet light to which all photographic emulsions are sensitive. *'''Acetic acid''' - chemical used for stop baths and to acidify acid fixing solution. *'''Acetone - solvent chemical used in certain processing solutions that contain materials not normally soluble in water.''' *'''Albumen paper''' - printing paper invented by Blanquart-Evrard in the mid-19th century where egg whites were used to coat the paper base prior to sensitization. The albumen added to the brightness of the white base and substantially improved printed highlights. *'''Allegory''' - work of art that treats one subject in the guise of another. An allegoric photograph usually illustrates a subject that embodies a moral "inner meaning". *'''Alum''' - chemical used in acid hardening fixing baths. *'''Aluminum compounds''' - groups of chemicals often used as hardeners in fixing baths. *'''Ambrotype''' - Mid-19th century photographic process introduced in 1851-52 by Frederick Scott Archer and Peter Fry. It used weak collodion negatives which were bleached and backed by a black background which produced the effect of a positive image. *'''Amidol''' - soluble reducing agent which works at low pH values. *'''Ammonium chloride''' - chemical used in toners and bleachers. *'''Ammonium Dichromate''' - chemical used as a sensitizer in Dichromated Holograms. *'''Ammonium persulfate''' - chemical used in super-proportional reducers. *'''Ammonium sulfide''' - pungent but essential chemical in sulfide or sepia toning. *'''Ammonium thiosulfate''' - highly active fixing agent used in rapid fixing solutions which works by converting unused silver halides to soluble complexes. *'''Amphitype''' - Mid-19th Century process based on an underexposed albumen-on-glass negative. This was viewed by reflected light against a black background to give a positive image similar to a ambrotype. *'''Anaglyph''' - result of forming stereoscopic pairs from two positives each dyed a different color, usually green or red. *'''Antiscreen plates''' - photographic plates containing dyes that reduce the blue sensitivity. Used unfiltered, they can give results similar to those obtained with yellow filtered orthochromatic plates. *'''Apodization''' - lens treatment designed to cut down diffraction fringes that appear around the images bright points of light. *'''Aquatint''' - etching technique allowing control of tonal areas to produce almost unlimited gradations from pale gray to black. Because of this it has also been used in photography as an alternative term for gum bichromate process. *'''Argentotype''' - Mid-19th century silver print process, on which the kallitype and sepia paper processes are based. *'''Aristotype''' - early commercial print type made on collodion-chloride or gelatin-chloride paper. *'''Azo dyes''' - compounds forming colors of great strength and purity. Used in camera filters and integral tripack dye-bleach materials. a5cb819f9093313bb4b2d3fd43ab62ac8397cf3c 0 804 1561 1560 2013-05-12T04:07:49Z Jsfisher 1 1 revision wikitext text/x-wiki [[Category:DCG]] [[Category:Beginner]] [[Category:Pecora]] By: [[John Pecora]] (Note: as this is an original article please do not edit it unless you are John. Please use the discussion page to comment on this work.) ==Abstract== <p>As the availability of green lasers becomes cheaper and more widespread, so does the potential for one to make their own dichromated gelatin (DCG) film and holograms. The purpose of this paper is to provide a basic step-by-step set of procedures such that the beginner may have success in producing their own DCG film and making simple DCG Holograms. There are many variables in the fabrication and processing which alter the aesthetics of a DCG hologram, most of which will be beyond the scope of this paper. And the basics here will not guarantee a professional quality hologram but will lead the reader down one correct path to successfully make DCG film and DCG holograms. It will be up the reader to take the next steps to perfect the quality and repeatability of the DCG hologram process. == Introduction == <p>DCG emulsion is made from a simple solution of ammonium (or potassium) dichromate, raw gelatin and water. Exposure to the DCG emulsion is done in the Green or Blue with higher sensitivity to the shorter wavelengths. Processing is simply a soak in Standard Photographic Fixer followed by a soak in water followed by a dehydrating process in one or more alcohol concentration baths. As a DCG hologram is susceptible to image loss when exposed to moisture, the DCG hologram will be sealed. There is a multitude of ways to perform each of these functions and the ones presented here have been tried and prove to work but may not be the best or suit a particular application for the DCG hologram. <p>'''Also, it is very important to insure safety at each step of of the process using good chemical safety practices, knowledge of the chemicals and equipment being used, proper disposal of chemicals, and common sense.''' It is not within the scope of this paper to point out safety hazards and it is the responsibility of the reader to research each and every potential safety hazard. I also suggest reading the entire paper first to familiarize your self with the procedures and note any materials and supplies you may need. ==Glass Preparation== <p>Cleaning the glass properly is important. If the glass is not cleaned properly the emulsion can lift off the glass in spots or completely during processing. Also, if there are any dust particles, the emulsion tends to have different properties at that area and a circular ring of deformation of the hologram will be seen around that area. Soak the glass in a 3% concentration of hydrochloric acid overnight. This can be bought as muriatic acid from most home improvement centers. You could also use a 25% concentration of household bleach. This procedure also works for recycling glass from previously coated plates, but I found the bleach takes longer. After soaking, using rubber gloves, scrub the plates with a plastic wool scrubby used for cleaning Teflon pans. Steel wool may scratch the glass. After scrubbing rinse the glass thoroughly under running water and place in a tray of running water. Then repeat the rinse process while rubbing again with the plastic wool. After the final rinse, lean the plates against the wall on a paper towel. Before the plates dry completely use a paper towel to dry off one plate at a time and continue to turn the paper towel until the plate is dry. You will hear and feel the difference between a damp plate and a dry one. Repeat for the other side of glass. Do not touch the plate with your skin or oils will be left behind which can also cause the emulsion not to stick to the glass. ==DCG Emulsion Fabrication== <p>DCG emulsion is comprised of an amount of distilled water, dry gelatin and ammonium (or potassium) dichromate. A good starting formula is 100:12:3 for the procedures described here. Take the water and place it in a heat resistant glass or plastic container. Place this on a magnetic heater/stirrer or in a double boiler. Add the gelatin to the water while it is cool and allow it to mix for a couple of minutes. If you are not using a heater/stirrer the stirring should be done by hand. Bring the temperature up slowly to a maximum of 120°F and a minimum of 110°F. Once the solution reaches the 110°F temperature, continue mixing until the gelatin mixture is completely dissolved. With the heater/stirrer allow the solution to be well mixed the entire time but not so fast as to cause excessive bubbles or foam. By hand, mix well for one minute every 5 minutes (this get laborious by hand). Mixing too long is better then under mixing, and I suggest 45 minutes after the minimum temperature is reached for a more aesthetic hologram. But again shorter times may be used as long as the gelatin is dissolved. It will look very clear and not cloudy when dissolved with no suspended particles. '''From this point on, a safelight must be used until the after the water bath in processing.''' A good safelight to use is a standard yellow incandescent bug light. Now add the dichromate. Allow this to mix until it is all dissolved (about 15 minutes) within the same temperature range. When this is completed, filter the mixture through a paper coffee filter into a clean container. A funnel or similar can be used to hold the coffee filter paper. It is best to allow the narrow end of the funnel to touch or be very close to the bottom of the final pouring container such that dripping from the funnel end does not produce bubbles. The container can be a beaker or other similar container that can easily be poured from but at the same time can be put back on the heater/stirrer or back in the double boiler to maintain the previous temperature range. If the emulsion is cooler during coating the final emulsion thickness will be thicker. Take a Q-tip and pop or remove any small bubbles that may be on the emulsion. The emulsion is now ready to coat. The emulsion can be stored at this time in a refrigerator, but should be sealed, labeled, and not allowed to be exposed to light. ==Plate Coating== <p>The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120°F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70°F). Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45 degree angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly, you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. Take the plate and immediately place it on a table and spin it as 78 RPM. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. I prefer the spin method. If you run out of emulsion in the pouring container, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. ==Exposing the Plate== <p>The plate is best after 4 hours old and can be up to a week(s) old. I have found the brightest holograms are between the 4 and 12 hour age. It seems when plates are older they are harder to get broadband replay and/or replay into shorter wavelengths and lose some sensitivity. The simplest recording geometry is a [[Single Beam Reflection]] in which the object is lying down on its back and the plate is laid right on top of the object. Make sure the object and plate do not wobble. Place the emulsion facing the object. As DCG is quite relaxing in the energy requirements I suggest doing test exposures with the times being doubled thus covering the largest range of times in the least amount or test exposures. Once the time range is found with your laser it will be easy to reproduce. An example is 10 seconds, 20 seconds, 40 seconds, 80 seconds, and 160 seconds. After exposure allow the plate to set in complete darkness for 2 to 5 minutes before processing. ==Processing the Plate== <p>All temperatures can be at room temperature (70°F). Take the plate and put it in Kodak Rapid Fixer with hardener. The Fixer should be mixed as per the instructions for the most dilute mixture (paper 1:7). Gently rock the tray until all yellow is gone then an additional 15 seconds. This should take anywhere from ½ minute to 2 minutes. I use a white tray to observe the yellow more easily. Once this is completed, place the plate in running water for 5 minutes (a tray of water can be used if running water is not available). I now turn on a quartz halogen light that shines on the spot where I will lean the hologram to blow it dry. Then take the plate and place it in 35% alcohol for 15 seconds. Then 70% alcohol for 15 seconds, then 91% alcohol for 15 seconds then finally 100% alcohol until diffraction is visible (anywhere from 15 seconds to two minutes or longer). As soon as diffraction (colors) is seen, allow another 15 seconds in that bath. Then take the plate out and lean it against the wall in the overhead light. With practice you will find which angle the diffraction is seen in the light and which way that relates to the visibility of the hologram when blow drying it. As soon as you lean the plate against the wall begin blow drying it with a hair dryer set on its hottest and strongest settings. Blow dry very close to the plate. Start at the center and in a circular motion move to the outside of the plate and repeat often. If the plate is leaning the right way the diffraction and image should start to get really bright. Continue drying until hologram in completely dry. You cannot over dry but you can under dry. This usually takes me 5 minutes minimum. ==Sealing the Hologram== <p>If the hologram is acceptable in quality and brightness to your liking, it must be sealed against moisture. After it is completely dry, use a razor to scrap off ¼" of emulsion from around all four edges. Three edges will be easy if you maintained ¼" when pouring the coating. The bottom wiped edge from coating will probably need the most attention. Now have another cleaned piece of glass ready the same size as the hologram. Mix up some 5 minute 2-part epoxy. I use a Q-Tip with the swab cut off. Now take the Q-Tip and use it to lay down a bead of epoxy around the entire cleaned edge on the emulsion side of the hologram. Take the clear cleaned piece of glass and place it over the hologram. You should see the epoxy sandwiched between the glass plates at the edge where the emulsion was scraped. Look closely and make sure there are not voids where the epoxy did not get sandwiched. Let the plates dry horizontally and check often to make sure the top plate does not slide and move into a different location. After about 15 minutes the hologram can be displayed as liked. b0d2e71ea0e52f30408a19f7ff81e2194b875784 0 159 1563 166 2013-05-12T04:07:49Z Jsfisher 1 1 revision wikitext text/x-wiki ==Here's my two cents:== From Joe Farina: Mix dichromate, gelatin, and water using some kind of double-boiler method, and keep it under 60C. Coat plates using whatever method you prefer. Let them dry under a gentle air flow for 4 hours. Store your plates in the refrigerator (use lock & lock or some other kind of airtight container). Make as many plates as possible to enable lots of tests. Do not desiccate or do anything else to them. (By the way, use Knox gelatin from the grocery store.) Now, do tests at your lesiure. Just take your container out of the fridge, let it get up to room temperature, and take a plate out (or you can immediately take it out if you hit the surface of the gelatin hard with warm air from a hairdryer to prevent excess condensation). Expose Denisyuk style with 100mW at 532. (I would say 2.5" X 2.5" plates would be good.) Let them set in the dark for 5 minutes after exposure. Rinse under cold tap water for a minute until the yellowness goes away. Soak in room-temperature water for a minute. Soak in 91% for a minute with agitation (room-temperature). Soak in 99% for three minutes with agitation (room-temperature). Then dry with hot air. If there is milkiness, you will need to harden the gelatin more after the dark reaction. You can user fixer or a 100W light bulb 6 inches away (for varying time periods) to do this. I prefer the light bulb method. See how your plates age, and how they perform over time. Change variables to see different results (well, I don't need to tell you this, since you probably know better than I do about trial-and-error work in holography). Just use the same principles you use to get such good silver halide holograms. One last word: don't try to pre-plan things too much. Just use the simplest DCG technique possible (it is really very simple if you have blue or green light). Don't make it any more complex than it has to be. End of lecture. * With a C315M (532nm) at 100mw start with a 1 to 3 minute exposure and adjust by factors of two to find the right exposure range. ie. 45 seconds, 90 seconds, 180 seconds. dd7709ca9e3fac825651a47da027a4535eec0201 0 160 1565 168 2013-05-12T04:07:49Z Jsfisher 1 1 revision wikitext text/x-wiki *BS - Beam Splitter *DE - Difraction Efficiency *DMD - Digital Micro-Mirror Device *EASLM - Electrically Addressed Spatial Light Modulation *H1 - A first generation hologram *H2 - A hologram of a hologram (copy) *H3 etc. - Sucessive generations of holograms *HOE - Holographic Optical Element *LASER - Light Amplification by Stimulated Emission of Radiation *l - liters *''l'' - length *LCD - Liquid Crystal Display *m - meters *''m'' - mass *M1, M2, M3 ect. - Mirror 1, Mirror 2, Mirror 3, etc. *mJ/cm^2 - milliJoules per centimeter squared *RH - Relative Humidity *SBR - Single Beam Reflection *SBT - Single Beam Transmission *SF - Spatial Filter *SI - International System of Units *SLM - Spatial Light Modulator *TEA *uJ/cm^2 - microJoules per centimeter squared *" - Inch = 25.4 mm *' - Foot = 12 inches Also see the [[Holography Glossary]]. ------------------------------------------------------------------------------ '''From Sergio on the Forum''' Some post recommendations internationally acept: SI writing style * Symbols do not have an appended period/full stop (.) unless at the end of a sentence. * Symbols are written in upright (Roman) type (m for metres, l for litres), so as to differentiate from the italic type used for variables (m for mass, l for length). By consensus of international standards bodies, this rule is applied independent of the font used for surrounding text.[10] * Symbols for units are written in lower case, except for symbols derived from the name of a person. For example, the unit of pressure is named after Blaise Pascal, so its symbol is written "Pa" whereas the unit itself is written "pascal". All symbols of prefixes larger than 103 (kilo) are also uppercase. o The one exception is the litre, whose original symbol "l" is unsuitably similar to the numeral "1" or the uppercase letter "i" (depending on the typeface used), at least in many English-speaking countries. The American National Institute of Standards and Technology recommends that "L" be used instead, a usage which is common in the US, Canada, Australia (but not elsewhere). This has been accepted as an alternative by the CGPM since 1979. The cursive ℓ is occasionally seen, especially in Japan and Greece, but this is not currently recommended by any standards body. For more information, see Litre. * The SI rule is that symbols of units are not pluralised, for example "25 kg" (not "25 kgs").[10] o The American National Institute of Standards and Technology has defined guidelines for American users of the SI.[11][12]These guidelines give guidance on pluralizing unit names: the plural is formed by using normal English grammar rules, for example, "henries" is the plural of "henry". The units lux, hertz, and siemens are exceptions from this rule: they remain the same in singular and plural. Note that this rule only applies to the full names of units, not to their symbols. * A space separates the number and the symbol, e.g. "2.21 kg", "7.3×102 m2", "22 K".[13][14] Exceptions are the symbols for plane angular degrees, minutes and seconds (°, ′ and ″), which are placed immediately after the number with no intervening space. * Spaces may be used as a thousands separator (1 000 000) in contrast to commas or periods (1,000,000 or 1.000.000) in order to reduce confusion resulting from the variation between these forms in different countries. In print, the space used for this purpose is typically narrower than that between words (commonly a thin space). * Any line break inside a number, inside a compound unit or between number and unit should be avoided, but if necessary the latter option should be used. * The 10th resolution of CGPM in 2003 declared that "the symbol for the decimal marker shall be either the point on the line or the comma on the line". In practice, the decimal point is used in English and the comma in most other European languages. * Symbols for derived units formed from multiple units by multiplication are joined with a space or centre dot (·), for example "N m" or "N·m".[15] * Symbols formed by division of two units are joined with a solidus (⁄), or given as a negative exponent. For example, the "metre per second" can be written "m/s", "m s−1", "m·s−1". Only one solidus should be used, i.e. "kg·m−1·s−2" is preferable to "kg/m/s²", and "kg/m·s²" is something else. Many computer users will type the / character provided on computer keyboards, which in turn produces the Unicode character U+002F, which is named solidus but is distinct from the Unicode solidus character, U+2044. * In Chinese, Japanese, and Korean language computing (CJK), some of the commonly used units, prefix-unit combinations, or unit-exponent combinations have been allocated predefined single characters taking up a full square. Unicode includes these in its CJK Compatibility and Letterlike Symbols subranges for back compatibility, without necessarily recommending future usage. * When writing dimensionless quantities, the terms 'ppb' (parts per billion) and 'ppt' (parts per trillion) are recognised as language-dependent terms since the value of billion and trillion can vary from language to language. SI therefore recommends avoiding these terms [1]. However, no alternative is suggested by the International Bureau of Weights and Measures (BIPM). d0e97b39c47c07f1e87a037dbbc69c4f0c89adf4 0 805 1567 1566 2013-05-12T04:07:49Z Jsfisher 1 1 revision wikitext text/x-wiki === About Ralcon and the founder, RDR === [[Image:Rdr.gif|right]]At Ralcon we design and fabricate prototype HOEs and will occasionally brass board the optical system that the HOE or HOEs will go into, a Spectrograph, a Holographic deflector and a Holo-memory are good examples. We also design and construct a wide variety of more conventional optical instruments such as Telescopes, Transmitters, Imaging systems, Illumination systems, Projectors and Head Mounted Displays. We are photon plumbers, charged with the task of routing as many precious photons as possible from their sources to their designated destinations. We also redesign and fix photon leaks and faulty light valves in existing systems. We deal with hot, cold and mixed photons in trickles or torrents. We are familiar with many kinds of photon generators, coherent, incoherent, partially coherent, fast and slow. Sometimes we can fix your photon generator, or at least tune it up or at least add some novel new accessory to it. Our main skill remains to be the redistribution of your photons into discreet patterns and directions. (All serious work is now done at Wasatch Photonics in Logan) Historically we started business with "jar holograms" and the invention of the Dichromate pendant in 1974. I produced what was probably the first very bright white light reflection hologram of a clock works, From which I launched Ralcon, (then known as the Electric Umbrella). 400 so-so pendant and plate designs followed until 1985 when I "gave" that business to others, currently operating as Krystal Holographics. Our HOE work actually began in 1972 but became profitable in 1979 with the development of an IBM designed bar code reader, for which we made the prototype scanners. We still make new holographic scanner/deflectors from time to time as requested and sell the technology to manufacture them. To date about 20 employees have learned more about holography through these ventures directly and possibly a hundred more through employment at spinoff companies that have sprouted from our original efforts. We still allow independent safe and competent holographers to work in this lab from time to time to complete their pet projects. We are a small company and plan to stay that way. We still resemble a family owned start up company with about $200,000 in assets and split our time between government contracts, aerospace, university and private small businesses. We actually ceased doing business in June of 2004 at the request the Cache County planning and zoning commission. My consulting hours are flexible and run from about 10 AM to midnight. I like to teach and readily accept paid tutorial jobs all over the country as the opportunities arise. I am also a pilot and often fly for fun around the neighborhood or even from coast to coast. <!-- img src="file:///C:/Docs/Images/rdr/Lab%20copter%20rdr.JPG" alt="Labs and toys" style="width: 663px; height: 443px;" align="right" --> RDR and his homebuilt *Rotorway 162F helicopter shortly after finishing it and before the first accident, looks a little different in 2005 after 4 mishaps and a lot of repairs.&nbsp; Also shown is an arial view of the labs and runways and RDR in front of the main lab holding an astronomy grating.<br> '''''Last modified on 11/24/99''''' [[Category:Rallison]] 46f55c7db62ae0bec9a076283e5305bf64705223 0 161 1569 170 2013-05-12T04:07:49Z Jsfisher 1 1 revision wikitext text/x-wiki First of all great thanks to Bill Jensen – without his works on SSY1 I wouldn’t catch pulsed laser bug. Thanks Bill  Here is some information about my homebuilt pulsed laser. I named it YAGna (polish girl’s name, if you visit Poland most of our highlander’s daughters will be Jagna ). YAGna uses SSY1 Nd:YAG laser capable of giving 170mJ; 4ns; 1064nm pulses. It wasn’t built for taking portraits – rather for shooting small objects (insects, splashes, falling drops of quicksilver or Ga-In alloy). Right now I’m running SSY1 just above lasing threshold (2*230V*sqrt(2) = 644V at main cap, which gives something like 6,7J of energy). For two reasons – I’m still using original polymer q-switch which is delicate, at this power level both flashlamp and KTP will last forever. And at lower energy levels beam quality is better (I hope there is less unwanted longitudinal modes). At 6,5 J I get up to 38mJ of IR, after conversion and filtering unconverted IR (a filter from a dead VHS camcorder) I have 8-15mJ of 532nm light. YAGna is equipped with Brewster window to increase conversion efficiency. Conversion efficiency is low since KTP is not working near its destruction limit. It is better for the crystal. [[image:SSY1a.jpg]] YAGna standing on her 3 BLACK legs  Tika looking suspiciously at YAGna. Originally there was a rebreather inside the box (used in coal mines). [[image:SSY2.jpg]] Front side of the laser. A diverging lens, piezoelectric lighter on top (for firing flashlamp) and 3 wing-nuts for adjusting the tilt of KTP crystal. The case is sealed with black electrician’s tape (the tape is black, not the electrician ) to prevent the optics from dusting. [[Image:SSY3.jpg]] Inside YAGna. From left to right – KTP kinematic mount (rotation + tilt), pulse forming network, SSY1 laser on its breadboard, voltage doubler (based on 2 microwave oven HV capacitors and 2 HV diodes), 24V power supply (for PFN1s vacuum relay – after depowering the main capacitor is discharged) and an aligning laser (which ceased to work after 20-30 shots – maybe 0,1% of IR coming out from HR was sufficient to destroy the diode after focusing). As you cans see there is still plenty of room inside, so an amplifier stage, additional PFN1 and trigger board will fit. Case dimensions are something like 30x20x10cm. [[Image:SSY4.jpg]] Diverging lens, KTP mount, PFN1 network and SSY1 laser. The lens is slightly off-line to avoid backreflections (or rather because there were some problems with gluing ) [[Image:SSY5.jpg]] KTP mount. The crystal is glued inside brass block with thermoconductive glue. There is a 5mm tungsten iris in front of 5x5x5mm KTP crystal. [[Image:SSY6.jpg]] SSY1 Nd:YAG laser. Attached to a breadboard using magnets. [[Image:SSY7.jpg]] Beam shape after diverging. Photo was take before I mounted the tungsten iris. Since now I was shooting small (up to 4x3cm) test holograms (at 6,5J), but I got a holo showing entire face profile from Bill (taken at 15J). You can see some of my holos at YouTube: *http://youtube.com/watch?v=6U9ebkGEtl4 *http://youtube.com/watch?v=d4XoRhb9SOg *http://youtube.com/watch?v=LhR24W8M_aA Approximate cost of YAGna so far is around $400 (KTP acosted $250). I think minimalist’s version of YAGna (KTP salvaged from a dead DPSS pointer) could cost below $200. What I’d like to improve in YAGna: * add amplifier stage(s) – 2 SSY1s are already waiting to be used. * add spatial filter (1m focal length, 0,5mm DIY tungsten pinhole). * add trigger board and a laser photogate to make holograms of splashes. * divide YAGna in two – laser head and PSU on separate boxes. * make YAGna portable to make holograms outdoors. * whatever else imagination allows  1279f9614b1ae4b20e8500e87f0fff65e4186f33 0 806 1571 1570 2013-05-12T04:07:50Z Jsfisher 1 1 revision wikitext text/x-wiki === Correcting steel table thermal drift with a fringe locker and auxiliary laser === A fringe locker is usually used to sense the recording wavelength fringes at the film plane and feedback correction to a moving mirror or moving prism in one leg of the set up. This works best and should always be tried first. Some set ups require the use of scarce blue photons which are not readily absorbed by ordinary silicon detectors. The power available for fringe locking is sometimes frightfully low and a "hard" lock is not possible. One solution is to buy more blue photons, another is to buy more sensitive photo diodes or photo transistors and install them in the head, another is to concentrate the light at the detectors with a lens, and still another would be to add more gain at the input stage. Even when there is enough light to make the locker work, there may be a diffuser or a diffuse object somewhere in the set up and therefore a diffuse wave that will not make a clean high contrast set of fringes to lock onto. For this case a few extra optics will often provide a second specular beam to use to form clean fringes. If none of these options are possible or attractive then there is still one more option that may work that requires several more optical mounts and optics but no more precious blue photons. For this option you need a simple 1 mw red HeNe or stabilized red or near IR diode laser as a secondary laser and enough optics to zig and zag down the same approximate paths taken by the primary blue laser light. The secondary light is required to share only one common surface with the primary light and it can usually remain on all the time and may even be considered part of the safe light fixturing. The object of using the locker in the first place is to compensate for long term drift in the table.This is not always the case but it is the most common task required and the most difficult problem related to long exposures. The components themselves may also warp slowly during an exposure but nothing much can be done about that. When the components are tall or raised above the tabletop a significant distance then table bowing may be a more serious problem than simple linear changes. In this case it is best to mount the beam combiner high up on the film plane, perhaps 2/3to 3/4 of the distance from the table top to the top of the film holder or film or plate. This positioning produces a good compromise between bow and linear compensation and will work when using primary laser light or secondary laser light. The only surface that has to be common to both primary and secondary waves is the moving mirror on the bimorph but it is also a good idea to mount the secondary wave combiner on the film plane whenever possible. This will make two surfaces essentially common and if the splitter can also be common, then so much the better. [[Image:Genlock.gif|center]]The above drawing shows a generalized locking scheme using a second red laser. The paths taken by the red light are roughly parallel to and of the same length as those taken by the blue light.Feedback from the red fringes formed by the combiner, BS3, will move the bimorph and change the path lengths for both colors simultaneously. Gross table drift will be adequately canceled but local or component drift and warpage will be unchanged. This system is very general and it would be fair to change the set up to record rainbow holograms and even use some reflection recording geometries in the blue zone shown without changing the red zone arrangement at all. Of course the acid test is to shoot a few shots and check for movement fringes and repeatability. The general reflection hologram is something of a special case. Fringe sensitivity to path length changes is at a maximum, often 10 times more sensitive than a transmission set up so some special precautions may have to be taken to get adequate stability. One precaution would be to follow the primary path more closely than shown, perhaps even mounting the red mirrors on the same posts with the blue mirrors whenever possible. Another precaution would be to calculate the correct angle of incidence of the red light on the bimorph mirror. The red angle will be different than the blue angle but related by the difference in wavelengths. The fringes in red are larger than the fringes in blue and the correct motion of the bimorph to compensate for a wave of error in the blue is smaller than for a wave of error in the red. The drawing shows the red beam at a shallow angle with respect to the normal of the bimorph mirror and the blue beam at a larger angle. In general this will be correct because the largest wavefront displacement occurs at 0 degrees and the smallest at grazing incidence. For small angles of incidence, say 40 degrees or less for the blue, the approximate angle for the red can be found by multiplying the blue angle by the ratio of wavelengths. As an example, if you were using a HeCd and a HeNe, as many holographers do, and your 442 light was set at 40 degrees from the normal, then the 633 light would be at442/633*40=28 degrees. This is only 1.3 degrees from the correct value or about 5% error,which is not enough to cause trouble. This little trick could also be compared to bathing a table in a constant temperature oil bath,which is sort of the brute force method of compensating for table drift. It might also be compared to buying a $30,000 research grade invar table, which also compensates for thermal drift by not having any to begin with. In any case, no matter how you look at it, if you have a thermal drift problem, and it is primarily the steel table that is growing 1 or 2 microns in a 20 minute exposure,then lock those fringes and relax. If you can't lock them directly then at least lock down the section of the table that you are using by building a secondary locking circuit. If you need a locker, I know of two manufacturers in this area, I haven't made a locker myself since 1983 but I use one frequently and consider it essential absolutely gotta have tooling. Fringe locker manufacturers:<br> *Inovar Devices inc,<br> ph (435) 245-5061, fax (435) 245-6948 *Excalibur Engineering,<br> ph (435) 755-9221, fax (435) 755-9321 <br> <br> Last modified on 8/14/98 [[Category:Rallison]] 16c8e189d191bfd318d750d6b521ab3950515529 0 162 1573 172 2013-05-12T04:07:50Z Jsfisher 1 1 revision wikitext text/x-wiki Holograms can be made with no mathematics. However, there is a mathematical basis for all of holography. Below we will explore the mathematical basis for holography. *[[Holography Transmission Equations Part I]] by Ed Wesly *[[Holography Transmission Equations Part II]] by Ed Wesly *[[The Calculus of Holography]] bb014b1458ba31d18d2bc5d1320340d2ae41742f 0 164 1575 176 2013-05-12T04:07:50Z Jsfisher 1 1 revision wikitext text/x-wiki Media Artist and innovator, since 1967, in the areas of film and video, avant-garde film, video art, holographic art, and more recently, stereoscopic 3D video, digital graphics - web media and web-based virtual reality. His films have received a number of awards, including a 1988 Los Angeles Film Critics Award, and his media art works are found in a number of international collections and have been exhibited internationally, including a 1997 stereoscopic 3D video showing at the Louvre, a 2002 film-video retrospective at the Electronic Media Arts Festival in Osnabruck, Germany, and a 2004 exhibition of 3D video, film, video at SeNef, Seoul, Korea. He also has an extensive background as a teacher in film production / film studies, is a past publisher of two periodicals on film and holography, and has invented / developed a number of film, video, holographic and 3D imaging techniques. In 2000-01 he was involved as Head of 2D/3D Graphics for the Mission Corporation (Bellevue, WA) in developments of speech-interactive (avatar-based) graphical interfaces for next-generation (post-PC) environments. He continues to create independent works in interactive 3D web graphics and installations. He has an extensive background as film and holographic arts producer, project lead and designer, critic, historian, writer, teacher and cultural activist, with special skills as cinematographer, videographer, holographic systems and installation designer, producer and director of films and videotapes, screen-writer, stereoscopic 3D videographer and editor, internet site designer, Speech-interactive Avatar UI designer and HTML and VRML programmer-creator. He is also a writer of screenplays, prose, and prose-poetry. d57cf989b83945ec045e7db776e1ed28e61daabd 0 165 1579 178 2013-05-12T04:07:50Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:AStephens.jpg]] [http://anait.com/ Anait's Web Site] Anait (Anait Arutunoff Stephens) was born in Berlin, Germany in 1922. On August 21, 1998, Anaït lost her battle against cancer in Santa Barbara, California, USA, in 1998. 1954 Instituto Nacional de Bellas Artes, Mexico, with Orozco Romero. 1958 Mexico City College, Mexico, with Toby Joysmith. 1964 University of California at Los Angeles, USA, with Dewain Valentine. 1971 School of Holography, San Francisco, California, USA, with Lloyd Cross. 1980 Museum of Holography, New York, USA, Artist-in-Residence. Professional Activities Lectures (selected) 1974 Studio lectures, Artist’s studio, Los Angeles, California, USA. 1977 Electro-Optics Seminar, Anaheim Convention Center, Anaheim, California, USA. 1978 Third Conference On Holography, USSR (the only woman and artist in attendance). Museum of Holography, New York, USA. 1980 Santa Barbara Museum of Art, Santa Barbara, California, USA. 1983 Studio lectures, Artist’s studio, New York, USA. 1986 The Royal Photographic Society Holography Group, London, UK. 1990 Chicago Art Institute, Chicago, Illinois, USA. 1991 Durand Art Institute, Lake Forest, Illinois, USA. 1992 Visiting tutor, Royal College of Art, London, UK. PUBLICATIONS Catalogues (selected) 1976 Through the Looking Glass, Museum of Holography, New York, USA. 1977 Theme and Variation, National Academy of Science, Association of Science – Technology Center, Washington, DC, USA. 1978 Alice in the Light World, Isetani Museum, Tokyo, Japan. 1979 ANAIT Retrospective 1966-1979, Museum Of Holography, New York, USA. 1983 Light Dimensions, Octagon, Bath, UK. 1984 Licht-Blicke, Deutsches Filmmuseum, Frankfurt/Main, Germany. 1987 Light Dreams, Kalamazoo Art Institute, Michigan, USA. 1991 Fiat Lux! Holografia, Asturias, Spain. 1991 Fourth International Exhibiton of Display Holography, Durand Art Institute, Lake Forest, Illinois, USA. Articles/interviews 1973 Blasco-Ibanez, “Down to the Sea in Sculpture”, Los Angeles Herald-Examiner Sunday Magazine, California Living. 1974 Melinda Wortz, “Los Angeles: Anait at Gallery 707”, Arts Magazine. 1978 Lincoln F. Johnson, “Defining, Evaluating Holography”, The Baltimore Sun. Anait, “My Art in the Domain of Reflection Holography” Leonardo Journal, Vol. 11 pp. 306-7. “A Letter to Leonardo”, Leonardo Journal, Vol. 11, pp. 351. 1979 William Wilson, Review, A-B Gallery, Los Angeles Times. 1980 James Wood, “Painterly Holography”, Artweek. 1981 Ricky Horton, “Anait: Holography as Art”, New York Arts Journal. 1987 Joan Crowder, Santa Barbara, News Press. OTHER INFORMATION 1972 Opened “Gallery 707”, Los Angeles. First gallery for women artists in LA. 1976 First solo art exhibit in the world in reflection holography: “Theme and Variation”. 1986 Listed in “Allgemeines Künstlerlexikon” (International Art Encyclopedia). 4b21ee688fe70223afe5dcd06cf39b0da24bfc6a 0 166 1581 180 2013-05-12T04:07:51Z Jsfisher 1 1 revision wikitext text/x-wiki The bio below was shamelessly pulled from Andres' home page and could use further editing. I have been involved in holography for quite some time. It started back in 1988 when I was in high school and needed to do some experiments for my school science fair week. At the time, all I had was a small 0.5mW HeNe from Metrologic that my grandfather bought for me after a very intense negation with him :), a limited supply of Agfa Holographic plates and one of the best resources of the time for the amateur holographer, the famous Holography Handbook by Fred Unterseher, Jeannene Hansen and Bob Schlesinger. The setup consisted of a sand box (as described in the handbook) resting on top of 4 inner tubes and 4 cinder blocks, some mirrors, lenses, Kodak D19 developer and a few other chemicals for development and bleaching (can’t remember the names). The process was very frustrating at the beginning. After using almost half the box of holographic plates, no hologram was obtained. You can imagine how wonderful it was when I was able to produce my first hologram. It’s a day I will never forget… I was only able to work with holography for a very limited period at that time and I was not able to do any holography work for 13 years. That all changed in 2003 when I met Michael Harrison. Susan, his wife, works with me and she used to bring Michael’s holograms to the office all the time. It didn’t take long for me to notice that and after talking with her decided to meet him. Well, suffice it to say, I got hooked instantly. Michael’s setup at his house is impressive and he was more that willing to help me get started again. This time though, things were a lot easier. First, I have another holographer that lives 5 minutes from my house, the internet, the holography forum for discussing anything holograhic with profesional and amateur holographers all over the world and last but not least, there is e-bay, the best source for equipment, lasers, optics, books, and anything relating to holography. My current setup is a lot more complex that my first one, it consists of an isolation table top built using a light weight material called Hexcel (a honeycomb material) sandwiched between three layers of steel sitting on top of inner tubes. A pair of 8” parabolic mirrors, spatial filter, magnetic bases to hold components, tons of lenses and mirrors and of course a laser (15mW HeNe). http://www.ghisays.net/default.php 00929dcbc49c1862c22afc4f93b7af016ec5560d 0 167 1583 182 2013-05-12T04:07:51Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.apepper.com/ Andrew's Web Site] Andrew Pepper studied Fine Art in the UK, where he began working with projected light and 3-D light installations. During this period he saw his first hologram in Paris, at an exhibition organised by Jody Burns and Posy Jackson, at the American Cultural Centre, in the City. He thought this would be the ideal medium to use to document his installations in 3-D. On conclusion of his Fine Art course, he spent 2 years at the Museum of Holography, in New York, as a Fulbright Scholar, and it was there that he learned how to make holograms at new York Holographic Labs. It was some time before he felt comfortable using the medium - wanting to find an alternative to the amazing 3-D effect which had originally attracted him to the medium. When he returned to the UK in 1981 he began lecturing and writing on creative holography and starting to produce his own work, which has now been exhibited in solo and group shows world-wide. He also completed a PhD in Fine Art Holography, the first of its type to be awarded by the Fine Art Department of the University of Reading. During 1988 Pepper was awarded a Lionel Robbins Memorial Scholarship which allowed him to continue his PhD research and carry out extensive exploration in a specially built holography studio at Reading University. In 1991 he moved to Cologne to take up a 5 year post with the newly established Academy of Media Arts, which as part of its studio activities was offering Holography under the direction of German Artist, Professor Dieter Jung. During this time in Germany he was able to realise a project he had been working on for several years earlier and founded the Creative Holography Index, The International Catalogue for Holography, which provided a very high quality collection of material about artists working in the medium, as well as commissioning several leading writers to give their views on the development of the field. While at the Academy he was introduced to the Internet and world wide web and eventually began to ‘translate’ the paper publication into a digital one, making it accessible to a much wider audience. He has remained interested in this idea of digital publishing and delivered several papers on the subject at international conferences. 1996 saw him move back to the UK to organise and chair Art in Holography2, a major international symposium which attracted speakers and delegates from all over the world and concentrated entirely on the art of the medium. From 1999 - 2004 he was director of the Shearwater Foundation Holography program, established by Posy Jackson in 1987. Each year it provided 100,000 US Dollars to support and encourage creative holography, as well as honouring several artists with the annual Holography Award, given to outstanding practitioners in recognition of their major contribution to the field. Pepper is a visiting lecturer at the Nottingham Trent University, School of Art and Design, a81150217a4ebfab9398686a109b60c4c291408e 0 168 1585 184 2013-05-12T04:07:51Z Jsfisher 1 1 revision wikitext text/x-wiki [[Sneaky Fish]] by Jeff Blyth dca874f2dad612d5707d3961b50d354bbb8721ba 0 169 1587 186 2013-05-12T04:07:51Z Jsfisher 1 1 revision wikitext text/x-wiki By: John Pecorra Well, there has been some talk about tables and plateholders so I thought I might post my plateholder design. It is original and I like it better then any plateholder I have ever used or seen. It allows from a 4" to a 20" format. It is quick and easy to load, even in the dark. It is very stable. I tried to put notes in the drawing to describe how it works but feel free to question anything. Also feel free to use the design if you want. It is all steel construction. The vertical poles are solid 1 1/2" rods. The angle iron on the top has holes cut out for the poles but the holes are slightly larger. There is no need to have the holes and rods within close tollerances. The top angle iron simply rests on the plate via the 2 sets of 2 screws as described. Then the thumbscrew is turned to place a slight bit of pressure from the angle iron to the pole to take the "ting' out but no stressing is involved as the large holes in the angle iron allow the angle iron to float freely, tilting to and away from the pole with the turn of the screw. The design of the top shades the very top part of the plate so nothing else is needed to keep the light from entering the edge of the plate. Another nice feature is there is room to squeeze light very close to the plate on the inside or outside of the pole depending on acutal film plate size. [[Image:AngleIronFilmHolder.jpg]] fd43596e97af92e42c70bb3ebc8212d2107107ea 0 170 1589 188 2013-05-12T04:07:51Z Jsfisher 1 1 revision wikitext text/x-wiki [[http://www.anamarianicholson.com/ Anna's Web Site]] f6bd52d29c8f2d410b070d90cd8b8218163113b6 0 171 1591 190 2013-05-12T04:07:51Z Jsfisher 1 1 revision wikitext text/x-wiki ==Holowiki Mirror== [http://www.holowiki.org/archive/holographyforum.tgz Holography Forum Archive] [http://www.holowiki.org/archive/text_only_holographyforum.tgz Holography Forum Archive text only] [http://www.holowiki.org/archive/holoforum.tgz holoforum Archive] [http://www.holowiki.org/archive/text_only_holoforum.tgz holoforum Archive text only] ==holoforum.org Archive== [http://holoforum.org/data/archives/index.html Archive directory at holoforum] 87750c01cd44ffb98699ec02365dc5d555282a66 0 172 1593 192 2013-05-12T04:07:51Z Jsfisher 1 1 revision wikitext text/x-wiki ==What is Art?== This is the age old question artists and critics have bantered around since before writing. Leo Tolstoy wrote an essay about it called [[What is Art?]]. "A large part of the beauty of a picture arises from the struggle which an artist wages with his limited medium." - ''Henri Matisse'' "Art is a man made object that is created to release an emotion from the artist and to invoke an emotion in a viewer." - ''Colin Kaminski'' A very informative treatment can be found in Maragret Benyon's [http://www.holonet.khm.de/benyonarchive/writings/gram.htm Holography as Art] ==The Hologenic Object== ==Composition== ==Lighting a Hologram== ==Fitting a Hologram into Your Decor== 795e43a762410d45d545577d6b75cabaef54a284 0 173 1595 194 2013-05-12T04:07:51Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.lasart.com Lasart] 0bd5063994c88bb56707ba655937ebc3c2b024fc 0 808 1597 1596 2013-05-12T04:07:52Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Sandbox_Kit.jpg|right]]The "original" hobbyist's approach to holography was described in the May 1979 issue of ''Physics Education'' as the aptly named ''Sandbox Holography''. Metrologic produced and sold identically named kit. The kit included some holographic film, chemicals for processing the film, and few lenses and mirrors. Not included were the laser (and at the time, that meant a moderately pricey helium-neon gas laser) nor the sandbox. Holography is extremely sensitive to movement, even microscopic movement, during the exposure. In conventional photography, movement will blur the image. With a hologram, since movement would completely alter the interference pattern between the direct and reflected laser light, the image can be lost completely. The sandbox was used to help eliminate vibration. In the late 1970's and early 1980's, the Metrologic Instruments Sandbox Holography kit might have cost you $150(US). A suitable laser, another $400 or so, and by the time you had the sandbox set up, you would be out $600 to $700 in 1980 dollars. For the curious, an updated version of the kit is still available from [http://i-fiberoptics.com/laser-kits-projects-detail.php?id=2140 Industrial Fiber Optics]. Industrial Fiber Optics purchased the educational laser and kit product line from Metrologic Instruments in November 2004. Although the [http://i-fiberoptics.com/pdf/45-733a_manual-revc.pdf Sandbox Holography] manual has details specific to the sandbox kit, it still provides a general introduction to holography for the beginner. == Modern Beginner's Kit == [[Image:Integraf_kit.jpg|right]]Diode lasers, like the ones found in common laser pointers, have completely changed what is needed for a suitable beginner's kit. You still need film and processing chemicals, but your first hologram can be made with no additional lenses or mirrors (because the diode laser beam naturally spreads), and there are some simple techniques developed over the years since the Sandbox kit was first introduced to eliminate the sandbox. In the new era, sandbox holography has evolved into [http://www.holoworld.com/shoebox/ Shoebox Holography], and there are now three, relatively economic ways for novice holographers to begin their hobby. #Buy the ''Shoebox Holography'' book. With that as a guide (or the equivalent information scoured from the Internet) acquire a suitable laser, holographic film, and chemicals and have at it. #Acquire one of the kits available from [http://www.integraf.com/holography_kit.htm Integraf]. (Film is more difficult to work with than glass plates, so the Standard or Student Kit is much preferred over the Budget Kit.) #Acquire a diffent type of kit from [http://www.litiholo.com Litiholo]. For the truly novice holographer, the Litiholo kit is a a bit of an oddity. With it, you can produce your first, interesting hologram. The kit comes with 20 plates, so there is plenty of opportunity for experimentation and the inevitable failure. Be aware, though, it is a self-contained unit. The holographic plates are self-developing, and the configuration is limited to the setups the kit intended. For the mildly curious individual or the elementary school aged child, the Litiholo kit is fabulous. For the slightly experienced holographer, it is good, if for nothing else than the exposure to polymer photo-materials. For the true beginner, though, it is a little like buying a TV dinner because you wanted to learn to cook. There is not enough "participation" to engage the beginner. Of the remaining two choices, simply buying a kit from Integraf saves you all the hassle of acquiring the parts individual. Plus you end up with a higher quality laser than what you would get from laser pointer. Some laser pointers have stability issues that may be unnoticeable in normal use, but disastrous in holography. The information that comes with the Integraf kit, or the identical [http://www.integraf.com/a-simple_holography.htm material available from the Integraf web site], or similar articles online, or from texts like the ''Shoebox Holography'' book, covers what to do next. Not much to it, really. == Beginner's FAQ == ; What is a hologram? : Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ; How little money/bother do I need to make one? : You can make your first hologram with about 2 hours of set up and about $100. ; What is the cheapest way to make a hologram? : [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ; Are the chemicals dangerous? : While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ; What sort of time commitment is there for making a hologram? : You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ; When can I have the lights 'on' during the procedure of making a hologram? : Once the emulsion has become insensitive to to light. For silver-halide holograms this is after the hologram is bleached. For dichromated gelatin holograms this is after the fixing and rinsing steps. ; What are the different kinds of holograms? : [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ; What is the single most important factor when making a hologram? : ''Stability!'' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ; How Does a LASER work? : For a simple introduction to lasers read [[How Do LASERs work?]]. ; Can I use a cheap red laser pointer to make holograms? : Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ; Can I use a Green Laser Pointer to make holograms? : So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ; Where are the Reference and Object beams in a Single Beam Reflection Hologram? : Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ; Some uses for [[Everyday Items]] in holography : Click here for [[Everyday Items]] that can save you money in holography! ; What is a [[Scratch-O-Gram]]? : A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and focusing it from a curved scratch to a point. ; What Books are Available for Holography? : See the [[Books]] section. [[Category:Beginner]] 46e5a56724df3308f69473de9a73e22fb71a28a6 0 809 1599 1598 2013-05-12T04:07:53Z Jsfisher 1 1 revision wikitext text/x-wiki [[Category:Rallison]] == COMPILED BY RALCON CORP SEPT. 1990 == Aberration-Free Linear Holographic Scanner and Its Application to a Diode-Laser Printer. H.Iwaoka and T. Shiozawa. bibl flow chart il diags Appl Opt 25:123-9 Ja 1 '86 Aberration Corrections for a POS Hologram Scanner. H. Ikeda and others. diags App Opt 18:2166-70 Jl 1 '79 Aberration Correction in One-Step Lens Image Plane Holography. B.W. Cohen and R. S. Lakes. bibl il diags Appl Opt 27:3322-3 Ag 15 '88 Aberration of Coefficients of Curved Holographic Optical Elements. P.E. Verboven and P.E. Lagasse. bibl diags. Appl Opt 25:4150-4 N 15'86 Aberrations in Nonparaxial Holography. K. Goto and M. Kitaoka. bibl diags J. Opt Soc Am A 5:397-402 Mr. '88 Aberrations of Holographic Toroidal Grating Systems. M.P. Chrisp. bibl diags Appl Opt 22:1508-18 My 15'83 Absolute S- and P-Plane Polarization Efficiencies for High Frequency Holographic Gratings in the VUV. A.J. Caruso and others. bibl il diags App Opt 20: 1764-76 My 15 '81 Absorption and Phase In-Line Holograms; a Comparison. P. Dunn and J. M. Walls bibl il App Opt 18:2171-4 Jl 1'79 Achromatic Combinations of Hologram Optical Elements. S.J. Bennett. bibl App Optics 15:542-5F '76 Achromatic Holographic Stereogram of Landsat Multispectral Scanner Data. S.A. Benton and others. il diags Opt Eng 24:338-40 Mr/Ap '85 Achromatic Triplet using Holographic Optical Elements. W. C. Sweatt. bibl App Opt 16: 1390-1 My '77 Advance in the Processing of Holograms. N.J. Phillips and D. Porter. bibl il Sci Instr 9:631-4 Ag '76 Advances in Bleaching Methods for Photographically Recorded Holograms. A. Graube. bibl App Optics 13:2942-6 D '74: Advances in Holographic Diffraction Gratings Point to Aberration-Free spectrometry. J.M.Lerner and others bibl diags Laser Focus 24:90+ Mr '88 Aliasing Error in Digital Holography. J.P. Allebach and others. bibl il App Opt 15:2183-8 S '76 All Single-Mode Fibre Optic Holographic System With Active Friunge Stabilization. M. Corke and others. il diag J.Phys E 18:185-6 Mr '85 Amateur Scientist: How to Make Holograms and Experiment With Them or With Ready-Made Holograms. C. L. Stong il diags Sci Am 216:122-8 F '67 Anaylsis of a Computer-Generated Binary-Phase Hologram. P.L. Ransom and R.F. Henton. bibl il diag App Optics 13:2765-7 D '74 Analysis of a 4-Port Bragg Device. P.D. Bloch and L. Solymer. bibl diags Inst E.E. Proc 127H:133-7 Je '80 Analysis of a Low-Aberration Holographic Scanner. T. Shiozawa and H.Iwaoka. bibl diags Appl Opt 27: 1992-7 My 15 '88 Analysis of an Active Stabilization System for a Holographic Setup. J. Frejlich and others. bibl il diags Apl Opt 27: 1967-76 My 15 '88 Analysis of Holographic Thin Film Grating Coupler. K. Ogawa and W.S.C. Chang. diag App Optics 12:2167-71 S '73 Analysis of Multiple Hologram Optical Elements with Low Dispersion and Low Aberrations. J.N. Latta. bibliog diags App Optics 11:1686-96 Ag '72 Analysis of Propagation at the Second-Order Bragg Angle of a Thick Holographic Grating. R. Alferness: bibl diags Opt Soc Am J. 66:353-62 Ap '76 Analysis of Volume Holographic Cylindrical Lenses. R.R.A.Syms and L. Solymar. bibl diags Opt Soc Am J. 72:179-86 F. '82 Analysis of Wave-Front Aberrations Caused by Deformation of Hologram Media. M. Matsumura. bibliog diags Opt Soc Am J. 64: 677-81 My '74 Analytic Design of Optimum Holographic Optical Elements. J.N. Cederquist and J.R. Fienup. bibl diags J Opt Soc Am A 4:699-705 Ap '87 Analytic Optimisation for Holographic Optical Elements. E. Hasman and A.A. Friesem. bibl diag J. Opt Soc Am A 6:62-72 Ja '89 Anecdotes on Dennis Gabor's days at CBS Laboratories. L Beiser. Opt Eng 23:SR8+ Ja/F '84 Angular Selectivity of Lithium Niobate Volume Holograms. T.K.Gaylord and F. K. Tittel. bibliog Diags J. App Phys 44: 4771-3 O '73 Anomalies of All-Dialectric Multilayer Coated Reflection Gratings as a Function of Groove Profile: an Experimental Study. L.B. Mashev and E. G Loewen. il Appl Opt 27:31-2 Ja 1 '88 Antenna-Aperture Distributions from Holographic Type of Radiation-Pattern measurement. P.J. Napler and R.H.T. Bates, bibliog diags Inst E.E.Proc 120:30-4 Ja'73 Application of Computer-Generated Holograms to Testing Optical Elements K.G. Birch and F. J. Green. bibliog 2pls diags App Phys 5:1982-92 N '72 Applications of Holography. bibl il diags Opt Eng 24:723-819 S/O '85 Applications of Laser Light. D. R. Herriott. il map diags Sci Am 219:140-4+ S '68 Approximate Bandwidth and Diffraction Efficiency in Thick Holograms. J.E. Ludman. bibl diags Am J. Physis 50:244-6 Mr.'82 Architecture for Optical Computing Using Holographic Associative Memories. H. Mada. bibl diags Appl Opt 24;2063-6 Jl 15 '85 Augmented Laser Scan Equations for Lenticular or Holographic Elements. LBeiser. bibl diags Appl Opt 22:1264-5 My 1 '83 Automatic design of Holographic Gratings for Seya-Namioka Monochromators A. Takahashi and T. Katayama. bibl diag Opt Soc Am J. 68: 1254-6 S'78 Automatic Shutter for Holography. L.H. Lin and H.L. Beauchamp. diag R. Sci Instr 41:1438-40 O '70 Beam Expander for Making Large Rainbow Holograms. diags Appl Opt 26:1815 My 15 "87 Beam Ratio in Multiple-Exposure Volume Holograms. K. Bazargan and others. bibl diags J Phys D. 21 no10S:S160-3 O 14 '88 Bibliography on Holograms. R.P. Chambers and J.S. Courtney-Pratt SMPTE J. 75:373-435, 759-73+ Ap.Ag '66 Binary Computer-Generated Holograms. 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Morris. bibl il diags Opt Eng 28:592-8 Je "89 CAD Holograms Cut the Cost of 3D Plant Modelling. V.Wyman. Engineer 264:44 Mr 19 '87 CO2 Laser Beam Shaping With Computer Generated Holograms. D.W. Sweeney and others. bibl il diag App Opt 16:547-9 Mr '77 Cell-Oriented On-axis Computer-Generated Holograms for use in the Fresnel Diffraction Mode. Y.H. Wu and P.Chavel. bibl il diags Appl Opt 23:228-38 Ja 15'84 Characteristics of Active and Passive 2-D Holographic Scanner Imaging Systems for the Middle Infrared. C.S. Ih and others. bibl diags Appl Opt 19:2041-5 Je 15 '80 Characteristics of Holographic Scanners Utilizing a Concave Auxiliary Reflector. C.S. Ih and others. bibl diags App Opt 20:1656-63 My 1 '81 Characteristics of Relief Phase Holograms Recorded in Photoresists. R.A. Bartolini bibliog il diags App Optics 13:129-39 Ja '74 Characterization of Volume and Phase Holographic Gratings. M Quintanilla and others. bibl il diags Appl Opt 23:214-17 Ja 15 '84; Checking Lenses with Holograms. 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Feldman and C.C. Guest. bibl diags Appl Opt 28:3134-7 Ag 1 '89 Interesting Paradix in Fourier Images. G.L. Rogers. bibliog il Opt Soc Am J 62:917- 18 Jl '72 Interference (holographic) Diffraction Gratings. M.C. Hutley. bibl il diags Sci Instr 9:513-20 Jl '76 Interference Patterns of Hologram Aberrations. T. Kubota and T. Ose. il diags Opt Soc Am J 61:1539-41 N. '71 Interferometric Testing of Large Optical Components with Circular Computer Holograms Y. Ichioka and A. W. Lohmann. diags App Optics 11:2597-602 N '72 Internal Reflections in Bleached Reflection Hologams. M.P. Owen and others. bibl diags Appl Opt 22:159-63 Ja 1 '83 Introduction to the Principles and Applications of Holography. J.W. Goodman. il diags IEEE Proc 59:1292-304 bibliog (p.1303-4) S '71 Ion and Plasma Assisted Etching of Holographic Gratings. D.A. Darbyshire and others. bibl diags Vacuum 36:55-60 Ja-Mr '86 Is There a Holography Industry? L.T. Kontnik. Laser Focus World 25:71-2 Jl '89 Iterative Method Applied to Image Reconstruction and to Computer-Generated Holograms. J.R. Fienup. bibl il diags Opt Eng 19:297-305 My '80 Kinoform. A Superefficient Pseudohologram. il Electro-Tech 83:40 Je '69 Large-Memory Real-Time Multichannel Multiplexed Pattern Recognition. D.A. Gregory and H.K. Liu. bibl il diags Appl Opt23:4560-70 D 15 '84 Large-Size Distortion-Free Computer-Generated Holograms in Photoresist. K. Biedermann and O. Holmgren. bibl il App Opt 16:2014-16 Ag '77 Laser Beam Scanners Constructed from Volume Holograms S.K. Case and V. Gerbig. bibl il diags Opt Eng 19:711-15 S/O '80 Laser Beam Scanning Using Computer-Generated Holograms. O. Bryngdahl and W.H. Lee. bibl il diags App Optics 15:183-94 Ja '76 Laser Diode Lensless MSF-HOE Correlator. F. Caimi and others. bibl il diag App Opt 19:2653-4 Ag 15 '80 Laser Machining with a Holographic Lens J. M. Moran. il diags Ap Optics 10:412-15 F '71 Laser Machining with Modulated Zone Plates. 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App Phys 46:3509 Ag '75 Thoery of Diffraction of Guided Optical Waves by Thick Holograms. R.P. Kenan. bibl diags J App Phys 46:4545-51 O '75 Theory of Hologram Formation in Photorefractive Media. K. Blotekjaer. bibl J App Phys 48:2495-501 Je '77 Thick Amplitude Holograms; Effect of Nonlinear Recording. C.R. Bendall and others. App Optics 11:2992-3 D '72 Thick Holograms in Photochromic Materials. D.R. Bosomworth and H.J. Gerritsen. bibliog il diags Ap Optics 7:95-8 Ja '68 Three-Color Hologram Zone Plates. W.E. Kock. bibliog il diag IEEE Proc 54:1610-12 N '66 Three-Dimensional Doppler Anemometer Using a Holographic Optical Element. F. Schneider and W. Windeln. bibl diags Appl Opt 27:4481-6 N 1 '88 Transient Holograms in dyed plastic. S. Calixto and R A. Lessard. bibl il Appl Opt 23:211-13 Ja 15 '84 Transmission Diffraction Gratings Composed of one Material with Anomalous Dispersion in the Visible Region. H.J. Gerritsen and others. bibl il Appl Opt 27:2781-5 Jl 1 '88 Two-Dimensional Theory of Volume Holograms With Electric Polarization in the Plane of the Grating. L. Solymar and C.J.R. Sheppard. bibl Opt Soc Am J 69:491-5 Ap '79 Ultraviolet Hologram Recording in Dichromated Gelatin. T.P. Sosnowski and H. Kogelnik. bibliog Ap Optics 9:2186-7 S '70 Use of a Holographic Filter to Modify the Coherence of a light field. D.Courjon and others. bibl il diags Opt Soc Am J 71:469-73 Ap '81 Use of a Holographic Lens for Producing Cylindrical Holographic Sterograms R.L. Fusek and L. Huff. bibl il diags Opt Eng 20:236-40 Mr/Ap '81 Use of Dynamic Theory to Describe Experimental Results from Volume Holography. R. Magnusson and T.K. Gaylord. bibl diags J. App Phys 47:190-9 Ja '76 Use of Holographic Optical Elements in Speckle Metrology. C. Shkher and G. V. Rao. bibl il diags Appl Opt 23:4592-5 D 15 '84 Use of Lens Arrays in Holograms. W.E. Kock. diags IEEE Proc 55:1103-4 Je '67 Use of Photoresist as a Holographic Recording Medium. M.J. Beesley and J.G. Castledine. il diags Ap Optics 9:2720-4D '70 Using Computer Generated Holograms to Test Aspheric Wavefronts. J.C. Wyant and V P. Bennett. bibliog il diags App Optics 11:2833-9 D '72 Using a Conventional Optical Design Program to Design Holographic Optical Elements. C.W. Chen. bibl diags Opt Eng 19:649-53 S/O '80 Versatile Beam Splitter for Holographers. P.K. Glanz and N. Haskell. diags Am J Phys 44:712 Jl '76:Discussion. M.E.Cox. 45:590-1 Je '77 Volume Hologram Formation in Photopolymer Materials. W.S. Colburn and K.A. Haines. bibliog il diags App Optics 10:1636-41 Jl '71 Volume Holograms Constructed from Computer Generated Masks. S.K. Case and W.J. Dallas. bibl il diags App Opt 17:2537-40 Ag 15 '78 Volume Holograms in Photochromic Materials. W.J. Thomlinson. bibl diags App Optics 14:2456-67 O '75 Volume Holographic Recording Characteristics of an Organic Medium. R.A. Bartolini and others. bibl App Optics 15:1261-5 My '76 Wave-Front Inversion Using a Thin Phase Hologram; a Computer Simulation. Q. Cao and J.W. Goodman. bibl flow charg il diags Appl Opt 23:4575-87 D 15 '84 Wavefront Multiplexing by Holography. H. J. Caulfield. il Ap Optics 9:1218-19 My '70 Wavefront-Reconstruction Mechanism in Blazed Holograms D. Kermisch. bibliog diags Opt Soc Am J 60:782-6 Je '70 Wavelength and Angular Selectivity of High Diffraction Efficiency Reflection Holograms in Silver Halide Photographic Emulsion. J.M. Heaton and L. Solymar. bibl diags Appl Opt 24:2931-6 S 15 '85 Wavelength Scaling Holographic Elements. M. Malin and H.E. Morrow. Opt Eng 20:756-8 S/O '81 Wavelength Performance of Holographic Optical Elements. T.Stone and N. George. bibl diags Appl Opt 24:3797-810 N 15 '85 White Light Hologram Technique. E.N.Leith and others il diags App Opt 17:3187-8 O 15 '78 Width-Modulated Complex Pserdorandom Diffuser. Y. Nakayama and M. Kato. diags Opt Soc Am J 70:1382-4 N '80 Zone-Plate Coded Imaging on a Microscopic Scale. N.M. Ceglio. bibl diag J App Phys 48:1563-5 Ap '77 Zone Plate Theory Based on Holography. M. H. Horman and H.H.M. Chau. bibliog il diags Ap Optics 6:317-22 F '67:Discussion. K.I. Clifford and G.S. Waldman. 6:1415:Reply. 1415-18 Ag '67 Zone Plate with Aberration Correction. E.N. Leith and J. Upatnieks. diag Opt Soc Am J 57:699 My '67 Books on Holography Abramson, Nils. The Making &amp; Evaluation of Holograms. LC 81-67905. 1981, 92.00 (ISBN 0-12-042820-2) Acad Pr. Applications of Holography in Mechanics Symposium Staff. Applications of Holography in Mechanics:Symposium, University of Southern California, 1971, Gottenberg, WG, ed LC 78-172086. pap. 23.50 (ISBN 0-317-08117-9, 2016842) Bks Demand. UML. Barilleaux, Rene P., ed, Holography Redefined: Thresholds. LC 84-61634. (Illus) 32p. (Orig). 1984 pap 4.00 (ISNB 0-936210-14-1) Mus Holography. Barret, N.S. Lasers &amp; Holograms. LC 87-52000. (Picture Library), (Illus). 32p. (gr.1- 6) 1985 PLB 10.90 (ISBN 0-531-04946-9) Watts. Basov, N.G. Lasers &amp; Holographic Data Processing. 142 p. 1985 pap 4.95 (ISBN 0-8285-2883-7, Pub. by Mir Bupns USSR.) Imported Pubns. -Lasers &amp; Holographic Data Processing. 142 p. 1984. 31.00x (ISBN 0 317-46643-7 Pub by Collets (UK)). State Mutual Bk. Brcic, V. Applications of Holography &amp; Hologram Interferometry to Photolasticity. 3nd ed. (CISM, International Centre for Mechanical Sciences, Courses &amp; Lectures: Vol. 14) (Illus) 58 p. 1975. pap. 10.20 (ISBN 0-387-81163-X) Springer-Veriag. Business Communications Staff, Holography: New Commercial Opportunities. 149p.1986. 1750.00 ISBN 0-89336-480-0, GB-074). BCC Butters, J.N. Holography &amp; Its Technology. (IEE Monograph: No 8).236 p 1972 36.00 (ISBN 0-901223-10-7, MO008). Inst Elect Eng. Butters, John Neil. Holography &amp; Its Technology. LC 73-179369 (Institution of Electrical Engineers, IIE Monograph Ser.:No. 8). (Illus.) pap. 59.00 (ISBN 0-317-08482- 82017592). Bks Demand UMI. Caulfield, H.J. &amp; Lu, Sun. The Applications of Holography. LC 77-107585. 138p. 1970. 18.50 ISBN 0-471-14080-5, Pub by Wiley). Krieger. Caulfield, H.J. ed. Handbook of Optical Holography. LC 79-51672. 1979. 89.50 (ISBN 0-12-165350-1). Acad Pr. Caulfield, H. John, et al. Holography Works. LC 83-62984. (Illus) 72 p. 1984. pap. 25.00 (ISBN 0-936210-13-3). Mus Holography. Cindrich, ed. Holographic Optics: Design &amp; Applications. 1988. 50.00 (ISBN 0- 89252-918-0, 833). SPIE Collier, R. et al eds. Optical Holography. 1977. student ed. 3995 (ISBN 0-12- 181052-6) Acad Pr. Collier, Robert J., et al. Optical Holography. 1971. 94. 50 (ISBN. 0-12-181050-X). Acad Pr. Colombeau, J.F. Differential Calculus &amp; Holomorphy. (Mathematical Studies: Vol 64) 456 p. 1982. 94.75 (ISBN 0-444-86397-4, North-Holland). Elsevier. David, Falk R, et al. Seeing the Light: Optics in Nature, Photography Color, Vision &amp; Holography. 464 p. 1985. text ed. 51.50 (ISBN 0-471-60385-6). Wiley. Dirtoft, Ingegard. Holography A New Method for Deformation Anlysis of Upper Complete Dentures in Vitro &amp; in Vivo. (Illus, Orig.). 1985. pap text ed 42.00x (ISBN 91-22- 00763-6, Pub by Almqvist &amp; Wiksell). Coronet Bks. Easy Way to Make Reflection Holograpms. 3.95 (ISBN 0-89816-072-3) Embee Pr. Ebbeni, ed. Progress in Holographic Applications. 223p. 1985. 43.00 (ISBN 0- 89252-635-1, 600). SPIE -Progress in Holography. 169p. 1987.43.00 (ISBN 0-89252-847-8, 812). SPIE Engineering Applications of Holography Symposium Staff. Engineering Applications of Holography: Proceedings of the Symposium, Los Angeles, 1972. pap 100.00 (ISBN 0- 317-09018-6, 2016751). Bks Demand UMI. Erf, Robert K., ed Holographic Nondestructive Testing. 1974. 69.50 ( ISBN 0-12- 241350-4) Acad Pr. Francon, M. Halography. 1974. 39.95 (ISBN 0-12-265750-0)Acad Pr. Hariharan, P. Optical Holography: Principles, Techniques &amp; Applications. (Cambridge Studies in Modern Optics: No. 2). (Illus) 331 p. 1984, pap. 24.95 Cambridge U Pr. Heckman, Philip. The Magic of Holography. LC 85-27489. (Illus). 256p. (YA) (gr 7 up). 1986.19.95 (ISBN 0-689-31168-0, Atheneum Childrens Bks.), Macmillan. Hildebrand, B. Percy &amp; Brenden, Byron B. An Introduction to Acoustical Holography. LC 73-23037, 224p. 1974. pap 18.95. (ISBN 0-306-2005-8 Plenum Pr.) Plenum Pub. Industrial Radiography Holography. (Illus). 160 p. member 9.50 (ISBN) 0-318- 17205-4 , Order No. 223); nonmember 13.00 Am Soc Nondestructive. Holography. Date not set.2450.00 (Isbn 0-89336-695-1 GB074R). BCC. Holography: Exploiting the Leading-Edge Developments. 340 p. 1987. 850.00 (ISBN 0-914993-15-1).Tech Insights Holography Markets. 161 p. 1984. 1285.00x (ISBN 0-88694-594-1.). Intl. Res. Dev. Huff, L., ed. Applications of Holography. 373p. 1985. 57.00 ( ISBN 0-89252-558-4 523). SPIE -Holography: Critical Reviews. 168p. 1985. 43.00 (ISBN 0-89252-567-3, 532). SPIE ICALEO Holography &amp; Information Processing Eighty-Three: Proceedings, Vol 41. 1984. 35.00 (ISBN 0-912035-22-6). Laser Inst. ICALEO Materials Processing Eighty-Three Proceedings, Vol. 38, 1984. 50.00 (ISBN 0-912035-19-6). Laser Inst. Jeong, ed Practical Holography, No Il. 157p. 1987. 43.00 (ISBN 0-89252-782-X 747) SPIE. Jeong &amp; Ludman, eds. Practical Holography, No.E. 140p. 1986. 43.00 (ISBN 0- 89252-650-5, 615). SPIE. Jeong, Tung H. Display Holography: Proceedings of the International Symposium 1982, Vol I. LC 83-81517. (Illus) 246p. 1983. 43.00 (ISBN 0-910535-02-7); pap 27.50 (ISBN 0-910535-09-9) Lake Forest. -Display Holography: Proceedings of the International Symposium 1985, Vol II LC 83-81517. (Illus) 492p. 1986. 65.00 (ISBN) 0-910535-05-1 pap 50.00 (ISBN 0-910535-04- 3):Lake Forest. -The Second International Exhibition of Holography. LC 83-80923. (Illus.) 24p. 1985. pap text ed. 12.00 (ISBN 0-910535-03-5). Lake Forest. Jeong, Tung Hon, International Exhibition of Holography. Croydon, Michael, compiled by. LC 82-83046. 26 p. (Orig). 1982. pap. text ed. 7.00 (ISBN 0-910535-00-0). Lake Forest. Juptner, W.P., ed Holography Techniques &amp; Applications, Vol 1026. 1989. 51.00 (ISBN 0-8194-0061-0.) SPIE Kallard, T. Laser Art &amp; Optical Transforms LC 78-70638. (Illus, Orig). 1979 pap. 12.50 (ISBN 0-87739-009-6). Optosonic Pr. Kasper, Joseph E. &amp; Feller, Steven A. The Complete Book of Holograms: How They Work &amp; How to Make Them. LC 87-16209. (Science Editions. Ser.) (Illus.) 216p. 1987 . pap. text ed. 16.95 (ISBN 0-471-62941-3) Wiley. Kobayashi, Shoshichi. Hyperbolic Manifolds &amp; Holomorphic Mappings. LC 70- 131390. (Pure &amp; Applied Mathematics Ser: No 2). pap. 39.30 (ISBN 0-317-08025-3, 2017855). Bks Demand UMI. Kock, Winston E. Lasers &amp; Holography: An Introduction to Coherent Optics. rev ed: (Illus). 128 p. 1981. pap 3.50 (ISBN 0-486-24041-X). Dover. Kostalanetz, Richard. On Holography. (Illus). 1979. 1500.00 (ISBN 0-685-95585-0). RK Edns. Laser Measurements. 145 p. 1985. 30.00 (ISBN 0-912035-13-7). Laser Inst. Lee,ed. Computer-Generated Holography. no II 1988. 45.00 (ISBN 0-89252-919-9, 884) SPIE. Machade, S. ed. Functional Analysis, Holomorphy &amp; Approximation Theory: Proceedings (Lecture Notes in Mathematics Ser.: Vol. 843). 636 p. 1981. pap. 38.80 (ISBN 0-387-10560-3) Springer-Veriag. Menzel, Fingerprint Detection with Lasers. 120 p. 1980. 55.00 (ISBN 0-8247-694-0). Dekker. Okoshi, T. Three-Dimensional Imaginary Techniques. 1976. 64.00 (ISBN 0-12- 525250-1). Acad Pr. Ostrovsky, Y.I., et al. Interferometry by Holography. (Springer Ser. in Optical Sciences: Vo. 20). (Illus) 280 p. 1980. 45.00 (ISBN 0-387-09886-0) Springer-Veriag. Robillard, Jean &amp; Caulfield, H. John, eds. Industrial Applications of Holography. (Illus). 192 p. 1989. 45.00 (ISBN 0-19-505855-0). Oxford U. Pr. Ross, F. &amp; Yerkes, E eds. Holography Marketplace, 1989. LC 88-31798. (Illus). 184 p. (Orig.) 1989 pap. text ed. 35.00 (ISBN 0-89496-047-4). Ross Bks. Saxby, Graham. Practical Holography. 560 p. 1988 text ed. 45.00 (ISBN 0-13- 693797-7) P-H. Schumann, W.&amp; Dubas, M. Holographic Interferometry: From the Scope of Deformation Analysis of Opaque Bodies. (Springer Ser. in Optical Sciences: Vol. 16). (Illus). 1979. 42.00 (ISBN 0-387-09371-0). Springer-Veriag. Schumann, W., et al Holography Deformation Analysis. (Series in Optical Sciences: Vol 46) (Illus). 1977. 53.00 (ISBN 0-387-13531-6) Springer-Veriag. Smith, H.M., ed Holographic Recording Materials. LC 77-24503. (Topics in Applied Physics: Vol 20). Illus). 1977. 53.00 (ISBN 0-387-08293-X). Springer-Veriag. Smith, Howard M. Principles of Holography 2nd ed. LC 75-5631. pap 73.30 (2056155) Bks Demand UMI Stoll, W. Value Distribution of Holomorphic Maps into Compact Complex Manifolds. LC 75-121987. (Lecture Notes in Mathematics: Vo. 135). 1970. pap 15.10 (ISBN 0-387- 04924-X) Springer Veriag. Stroke, George W. Introduction to Coherent Optics &amp; Halography. 2nd ed (Illus) 1969. 64.50 (ISBN 0-12-673956-0). Acad PR. Unterseher, Fred, et al. The Holography Handbook, New ed. (Illus). 408p. (Orig.) 1982. pap 16.95 (ISBN 0-89496-017-2). Ross Bks. Vasilenko, G.I. &amp; Tsibul'kin, L.M. Image Recognition by Holography. Tybulewicz, Albin, tr from Rus. LC 88-23739. (Illus) 342p. 1989 85.00x (ISBN 0-306-11017-2, Consultants). Plenum Pub. Vest, ed Holographic Nondestructive Testing: Critical Review of Technology. 117 p. 1986. 55.00 (ISBN 0-89252-639-4, 604). SPIE Vest, Charles M. Holographic Interferometry, LC 78-14883. (Wiley Series in Pure &amp; Applied Optics). 465p. 1979. text ed. 71.95x (ISBN 0-471-90683-2, Pub. by Wiley- Interscience). Wiley Wang, et al, eds. Holography Applications 591p. 1986. 72.00 (ISBN 0-89252-708-0, 673 )SPIE Wenyon, Michael. Understanding Holography, LC 78-965 (Illus) 176 p. 1984. 14.95 (ISBN) 0-668-06414-5); pap 8.95 (ISBN 0-668-06203-7) Arco. Yaroslavskii, L.P. &amp; Merzlyakov, N.S. Methods of Digital Holography. LC 80-16286 182 p. 1980. 69.50x (ISBN 0-306-10963-8, Consultants.). Plenum Pub. </pre> <br clear="ALL"><p></p><hr><hr> <strong><em> Last modified on 7/21/99 <br> e61dda029343401d42e0ecff616aa8b347f391fd 0 178 1601 204 2013-05-12T04:07:53Z Jsfisher 1 1 revision wikitext text/x-wiki The backgrounds of holographers are extremely varied, as can be seen below. Without these people's tireless efforts, holography would have remained a mere laboratory curiosity, rarely to be seen elsewhere. As a result of their work, holographic techniques are more and more frequently used in science, technology, medicine, measurement and art. With the advent of lower cost lasers and recording materials, and also due to the work of the dedicated holographic popularizers among those listed below, there is a small but growing international community of amateur holographers, and it is not uncommon to have hands-on holography courses presented in elementary schools. This project is designed to collect in one place biographical info on all of the people who have made holography possible. Please feel free to post your biographies here. If you know a name but don't know the details, just add the name and we will work on getting a biography. *[[Dave Battin]] *[[Paul D. Barefoot]] *[[Kaveh Bazargan]] *[[Margaret Benyon]] *[[Steve Benton]] *[[Rudie Berkhout]] *[[Hans Bjelkhagen]] *[[Jeff Blyth]] *[[Patrick Boyd]] *[[Pam Brasier]] *[[Harriet Casdin-Silver]] *[[Greg Cherry]] *[[Melissa Crenshaw]] *[[Loyd Cross]] *[[Salvador Dali]] *[[Rebecca Deem]] *[[Frank DeFreitas]] *[[Yuri Denisyuk]] *[[Georges Dyens]] *[[Phil Edelbrock]] *[[Gregg E. Favalora]] *[[Dennis Gabor]] *[[Yves Gentet]] *[[Andres Ghisays]] *[[Nancy J. Gorglione]] *[[Michael Harrison]] *[[Dr. Jeong]] T. J. *[[Frithioff Johansen]] *[[Pearl John]] *[[Colin Kaminski]] *[[John Kaufman]] *[[Roderic Lakes]] *[[Emmett Leith]] *[[Sharon McCormack]] *[[Mike Medora]] *[[Ronnie Michael]] *[[Lon Moore]] *[[Rob Munday]] *[[August Muth]] *[[Ikuo Nakamura]] *[[Anna Maria Nicholson]] *[[Caroline Palmer]] *[[Dinesh Padiyar]] *[[Joy Padiyar]] *[[John Pecora]] *[[Andrew Pepper]] *[[Hart Perry]] *[[Jerry Pethick]] *[[Nicholas Phillips]] *[[Greg Quinn]] *[[Al Razutis]] *[[Jonathan Ross]] *[[Graham Saxby]] *[[Dan Schweitzer]] *[[Mark Segal]] *[[Walter Spierings]] *[[Anait Stephens]] *[[Fred Un'''Bold text'''terseher]] *[[Juris Upatnieks]] *[[Doris Vila]] *[[John Webster]] *[[Edward Wesly]] *[[Mieczyslaw Wolfke]] *[[Sergey Vorobyov]] *[[Sergey Zharkiy]] 754a124146110fa564366d0eed77ce2a48b37667 0 810 1603 1602 2013-05-12T04:07:53Z Jsfisher 1 1 revision wikitext text/x-wiki == Blazed binary optics, from pc to plastic == Richard D. Rallison<br> Scott R. Schicker<br> RALCON CORP<br> Stephen E. Bialkowski, Ph.D.<br> Dept of Chem and Biochem<br> Utah State University<br> Logan, Utah 84322<br> == SUMMARY == A zone plate with 250 zones has been computed on a 386 machine and printed on 100 sheets of plain paper in a NEC LC890 printer. It was computed in Postscript language with 8 levels of grey in each zone and measured 75 inches in diameter before photoreduction to millimeter dimensions in a Nikon FA camera using Kodak 5052 TMX film. The reductions were made from 50 to 300 times to test the range of system resolution, fine grain Illford holographic film was substituted to test the camera MTF. Three micron layers of resist were used to get maximum phase shift and embossing masters of epoxy and nickel were made and evaluated. The final elements are embossed or cast in a variety of plastics and epoxies on glass, metal or semiconductor substrates. The final copies are efficient micro lenses and gratings useful for fabricating beam deflectors and a variety of stable optical interconnects. Resolutions are not as high as electron beam or laser scanning techniques but equipment and fabrication costs are low. We wrote a program named ZONE2 that will compute and print round or elliptical geometric zone plates with up to 20 shades of grey between zones. A second program named LINES writes linear gratings of the same sort, both generate postscript files that can be scaled as large as the computer system will handle. In our case the practicle upper limit was a 10 megabyte file that printed 250 zones times 8 shades of grey spread over 100 pages. The number of zones per page was found to be limited by the printer artifacts related to printer resolution and the computing of shades of grey in the postscript language. The number of grey shades is similarly limited to about 11 distinguishable shades in the inner zones and perhaps 6 to 8 shades in the outer zones. Geometric zone plates are free of aberrations only for f #s larger than 10 so the restriction to 250 zones means we are limited to a lens that is 10 mm in diameter with a focal length of 100 mm at a wavelength of 500 nm. If we had added a term and made the calculations for an interferometric zone plate we could have gone to an f# of 4 without aberrations using 250 zones in a diameter of 4 mm and a focal length of 16 mm. For some applications we could ignore the spherical aberrations of the geometric zone plate used at lower f #s and we made some in the f # 4 range for examination. Optics in this range require resolutions better than 250 l/mm at their outer limits. The camera was fitted with an f/2.8 Micro-NIKKOR 50mm lens which could reasonably resolve 4 micron details over a small angular field. The camera had to be loaded with individual frames of ILLFORD holographic film to insure a large enough film MTF, then each piece was hand processed in DEKTOL developer which yielded good grey scale. Shooting was done outside on a sunny day at distances of between 12 and 100 feet. The zone plate was cut and pieced together on an 8 by 7 foot substrate made from 2 inch thick urethane foam laminated to smooth white paneling. For maximum thickness we chose SHIPLEY #1400-37 PhotoResist spun onto 2.5 X 2.5 inch float glass squares for making the surface-relief copies of the Silver Halide masters. We had no previous experience with this material and this is what we found would work. 1) We set up a Gyrex IR oven with the low pre-heat on, the main heater control set to position seven, and the conveyer speed set to slowest. We washed the substrates, rinsed them in D.I. water, and dried them in a class 100 clean hood. When the substrates appeared dry,we ran them through the I.R. oven two or three times to dehydrate them and stored them in a clean hood until ready to coat. 2) The oven is then cooled down and set up for the "Soft Bake" step. The pre-heater is turned off, the heater is set to one,(130 to 140 degrees F) and the conveyer is set to its slowest speed ( 6 minutes). A soft bake for the photoresist is accomplished by running it through the oven only twice in succession. Over-baked resist does not react well to light. 3) We use a multiple discreet speed DC spin-coater with a small suction cup for applying the photoresist. The speed control is set to get approximately 900 revs per minute as measured by a mechanical tachometer. The spin coater box is lined with aluminum foil and set up on a class 100 clean bench. A substrate is centered on a suction cup and 3ml of the resist is applied to the substrate. The assembly is moved so as to spread the resist evenly over the surface to be coated. The suction cup is inserted into the spin-coater and spun for three minutes.This produced a dry 6 micron thick coating as measured by a .001 inch resolution dial indicator, ( 2.5 microns per division). 4) After a substrate is coated, immediately run it through the oven for the soft bake step. It is advisable to establish a routine so that residual solvents are uniformly distributed and sensitivity is then consistent and uniform across the substrate and from plate to plate. 5) To make a contact copy of a silver-halide master, we place the master with the emulsion side up onto the photoresist and weight the master down with a half inch thick slab of suprasil. Next we place a non-reflective mask over the suprasil to prevent edge scattering and reflections. Lastly, we expose the whole works to a standard 175 WATT mercury vapor yard light from which the outer glass globe has been removed to allow the full spectrum of UV to escape. Thirty minutes at a distance of one foot worked quite well for us and the lamp had to be fan cooled at that distance or it would melt the plastic. 6) The development process consists of washing the exposed photoresist off of the substrate with a dilute solution of MicroPosit 351 developer ( more commonly known as sodium hydroxide ). We used a solution of three parts water with one part of the MicroPosit 351 Developer Concentrate. Development is carried out in a small tank by uniformly immersing the plate and gently agitating only two times back and forth and then letting the plate lean against the side of the tank film side down. After developing the exposed resist for four minutes, we then rinsed it in a dilute solution of Kodak stop-bath ( 3 ml per 500 ml total volume ) and then De Ionized water for ten minutes. We tried using photo-flow in the rinse water but it left a residue. Dry the finished gratings in a clean hood under a gentle flow of air. DO NOT blow it dry with high pressure air, the grating is easily blown apart at this stage. 7) When we tried hard-baking the gratings in the Gyrex oven we succeeded in melting the resist. We now skip the hard-bake step as it does not seem to be necessary for electroplating or replicating with epoxy. We exported some resist masters to Dazzle Enterprizes for electro plating but we are preparing to do our own plating in the future. Electro plating is necessary to replicate with full depth onto substrates using UV epoxies or thin plastic films. We received 8 shims from two different resist masters made at 28 microns from Dazzle. The shims were made in 4 different thicknesses, 2, 4, 6, and 8 mils thick and were not as flat as we had hoped. Casting against them was carried out with UV epoxies and a nip roller with good results when using the 4 mil shims. Copies were also easily embossed into various plastics using a solvent and a Foster replicator. The Foster replicator is a hand cranked ringer, commonly used to ring out wet articles of clothing. '''''Last modified on 6/3/99<br>''''' [[Category:Rallison]] 9361d6065b3cca7946fe76e43324fa83709fb7b1 0 179 1605 206 2013-05-12T04:07:53Z Jsfisher 1 1 revision wikitext text/x-wiki The Blyth Colour Tuning method originated from an observation Jeff posted to the forum and its testing was taken up by a number of people. The results were very promising. The original thread is here: [http://www.holographyforum.org/phpBB2/viewtopic.php?f=2&t=5224 Blyth Colour Tuning Thread] ==Preperation== Stock Solution: *15g Citric Acid *100ml Water Dilute as needed. Soak the hologram to be swelled for 30 minutes. Then dry. Amazingly squeegee technique is not very important here! ==Paulos Test== I cut a 15 x 20 cm film hologram in 4 pieces and applied Jeff's Citric Acid solution method. The result: # (upper left): untreated (514 nm) # (upper right) 11.75 % Citric Acid (=15% x 0.75) # (down left) 7.5 % Citric Acid (=15% x 0.5) # (down right) 15 % Citric Acid [[Image:citric.jpg]] The photo is not the best one (the hologram is free of any noise), but the effect of the various concentrations is obvious. In comparison to sorbitol-treated holograms, the overall quality is better. * Exposure at 514 nm * Holographic film: Finegrained HF-53 from ORWO * This emulsion is much harder than Slavich material. ==Theory== From Jeff Blyth I have been doing a bit more on this since I have receiving an appreciative email from Rob Taylor (Forth Dimension Holographics) about the newly found virtues of the citric acid post swell system.. In it he mentions how forgiving it is to the squeegeeing. technique. I have noticed this too and have just been wiping off the excess citric acid solution casually with tissues and have not seen smeary streaks of darker red which would have occurred with sorbitol solution. Now this convenient fact indicates something about what is happening down at the molecular level. Also I just might possibly have discovered something of interest for DCGers to investigate as a means of changing those finished too-blue colored hologram into red ones –a trick which I think John Pecora has discussed more than once on this Forum over recent years. However with only 2 days of observation I am being rather optimistic to think I have a long term answer to that old perennial DCG problem but I hope that DCG’ers will now try some experiments with old “Bluies and Greenies” as John puts it before just recycling the glass! I will go into a bit of DCG detail at the end of this post. First though I need to hypothesize what is happening at the molecular level to try to understand the observation about squeegeeing technique being less critical with citric acid solution compared to sorbitol or glycerol solution. So as we all know, the building bricks of gelatin are amino acids. In neutral pH conditions these make themselves into internal acid–base structures with the negative – positive ions neutralising each other. The swelling in water is caused by both the positive and negative ions choosing to open themselves up to accommodating lots of water molecules which take on partial induced charges opposite to the ions they surround. So the amino positive ions get surrounded by a cloud of partially negatively charged water molecules and vice versa around the negatively charged acid groups . This allows the original electrostatic attraction between the oppositely charged components of the amino acid to slacken and the components to move apart by a factor of 2 or 3 times their unswollen distance. An accepted way of keeping gelatin based holograms swollen with water has been to try to replace a lot of the water with non- volatile very hydrophilic “polyalcohols” such as glycerol or sorbitol . These alcohols get involved in the cloud of water molecules surrounding the charged amino acid groups. The size of this cloud of water molecules around the oppositely charged amino acids is very imprecise , variable and dynamic, (this description will be important), it instantly can change with temperature and humidity changes so it is difficult to control color changes of gelatin based reflection holograms. (They act as superb humidity change sensors---a fact I am personally gaining from in the development of “Smart” holograms to test for water in aviation fuel.).. Just breathing on them can make a wavelength change of tens of nanometers as we all know. However in the case of a hologram treated with citric acid and then blow dried at room temperature we are left with a swollen gelatin which is different from the case of one swollen with water plus sorbitol or glycerol. In citric acid we have in effect the line of 3 carbons in glycerol now with their alcohol groups (-OH) replaced by carboxylic acid groups (-COOH) except for the central carbon which has the (-COOH) added in place of H leaving one alcohol OH still there (more on this later). These –COOH groups introduce a different effect to cause the swelling of the gelatin. This time the citric acid (-COOH) groups can partially displace the original internal (-COOH) groups from their attraction to the amino groups. These displaced (-COOH) groups are still firmly attached to the gelatin biopolymer of course and are not free to wander off in solution so the rest of the citric acid molecule is forced to be accommodated into the gelatin structure as most of the surrounding water is now evaporated off thus leaving the gelatin in a swollen state when it is left to equilibrate with ambient humidity.--- Fortunately it is a chemically weak arrangement easily completely reversed by plenty of fresh water so that it becomes energetically more favourable for all the ions involved to go back to surrounding themselves with water-molecule clouds again . The upshot of this is that if you are not satisfied with the color of your treated hologram you can go back to square one without any difficulty . I have not found the slightest trace of the effect of citric acid after rewashing in water. --An important feature for any precious holograms whose color you are trying to tweak. In the above model one can sense why the removal of excess surface liquid on a hologram treated with citric acid solution is more forgiving (in the final result) from an unequal treatment with a squeegee blade compared to the same situation with an excess of sorbitol solution. In the case of excess sorbitol that final sheath or cloud of water/sorbitol molecules which I described above as "very imprecise , variable and dynamic", as they surround the amino acid ions they can be far too sensitive to small variations in residual water causing corresponding local variations in reddening of the final replay color as the clouds expand or contract. Whereas in the case of the citric acid, the reddening is caused mainly by a specific alteration of the internal molecular structures of the amino acids and perhaps not much by a variable cloud around the ion.. Now experienced DCGers have long since found that you cannot change the color of a finished too-blue DCG by playing around with sorbitol treatment. Anything that attracts water is anathema to DCG holograms. So the question naturally arises can one somehow do it with this different citric acid mechanism? Well I took a blue green finished DCG , left it in 10% citric acid for 10 mins, (I cut the time down from my previous 30 min recommendation because I noticed the gelatin was starting to come off the glass after 5 mins) I then briefly wiped it with a tissue an plunged it into a stirred beaker of ~100% ipa at room temperature. ( I needed to avoid using ipa/water solution as it was likely to loose citric acid. The acid fortunately seemed to prefer to keep its weak attraction to the gelatin rather than dissolve in ipa. only). The good news is that the resulting hologram after a long cool blow was a deep red hologram instead of a blue green one. But the bad news is that that only 3 hours later it had vanished.. But ……don’t go away yet…………. I tried a variant. …… The problem was of course likely to be too much water attracted in still--the water cloud around ions was probably still there to some extent which caused the air- void fringe structure to be unstable and disappear. So could an improvement be got by using an alternative organic acid without a residual alcohol –OH group still present? So I tried succinic acid instead. This is a non- poisonous but quite strong organic acid (a “natural” product too) with the 2 alcohol groups in ethylene glycol replaced by –COOH groups. I found that it saturated at room temperature at around the 6% level but treating green silver halide holos with it did make useful color shifts to yellow (in the case of BB plates but not in the case of the harder Fuji film,) it was though much less effective at causing the amount of color shift you can get from the same concentration of citric acid. The question is then is this less hydrophilic acid able to keep a color shift in DCG? So far my test sample is still maintaining its green to orange shift after 36 hours but I would not put any money on its permanence. So I am hoping some DCGer will pick the idea up, get in a bit of succinic acid and play around with sealing it up etc. ---it could be an interesting alternative to recycling those “Bluies”. Jeff 1bbe75e63fe26cf167311d6b7396886cb3c5dbd9 0 180 1607 208 2013-05-12T04:07:53Z Jsfisher 1 1 revision wikitext text/x-wiki ==Must Haves== *Saxby, G., "Practical Holography" Third Edition, IOP, 2003, ISBN 0750309121. Reviews: [http://www.designerinlight.com/holo/graham.htm][http://www.dragonseye.com/blog/archives/17-Practical-Holography-3rd-Edition,-Graham-Saxby.html] *Unterseher, F., Hansen, J., Schlesing, B., "Holography Handbook", Ross Books, 1982, ISBN 0894960164. Reviews: [http://www.dragonseye.com/blog/archives/18-Holography-Handbook,-Unterseher,-et.-al.html] *Bjelkhagen, H., "Silver Halide Recording Materials for Holography", Springer-Verlag. 1996, ISBN 3540565760 *Hariharan, P., "Optical Holography", Cambridge University Press, 1996, ISBN 0521439655 *Keechner, W., "Solid State Laser Engineering", Springer, 1999, ISBN 3540650644 *DeFreitas, F., Rhody, A., Michael, S., "Shoebox Holography", Ross Books, 2000, ISBN 0894960601 ==Other Books== *Saleh, B., Teich, M., "Fundamentals of Photonics", John Wiley and Sons, 1991 *Jung, T. editor, "Holographic Imaging and Materials", Vol. 2043, SPIE, 1994 *Kock, W., "Engineering Applications of Lasers and Holography", Plenum Press, 1969 *Kasper, J., Feller, S., " The Complete Book of Holograms", John Wiley and Sons, 1987 *Cathey, W., "Optical Information Processing and Holography", John Wiley and Sons, 1974 *Brown, R., "Lasers: Tools of Modern Technology", Doubleday, 1968 *Jung, T. editor, "Practical Holography II", SPIE, 1987 *Iovine, J., "Homemade Holograms", Tab Books, 1990 *McGomb, G., "The Laser Cookbook", Tab Books, 1988 *Saxby, G., "Holograms", Focal Press, 1980 *Hecht, J., Teresi, D., " Lasers: Light of a Million Uses", Dover, 1998 *Horn, D., "Laser Experimenters Handbook", Tab Books, 1988 *Kock, W., "Lasers and Holography", Doubleday, 1981 *Ross, J., "3x8+1", Holograms 3-D, 1994 *Bergquist, C., "Laser Design Toolkit", Prompt Publications, 1999 *Smith, H., "Principles of Holography", Wiley, 1969 *Vacca, J., "Holograms and Holography", Charles River Media, 2001. Reviews: [http://www.dragonseye.com/blog/archives/19-Holograms-and-Holography-Vacca.html] *Gorglione, N. editor,"The Archives of Holography", Leonardo Vol. 25 No. 5, Pergamon Press, 1992 ==Holography Marketplace== *Ross, F., Yerkes, E., editors"Holography Marketplace: Second Edition", Ross Books, 1990 *Kluepfel, B., Ross, F., editors, "Holography Marketplace: Third Edition", Ross Books, 1991 *Kluepfel, B., Ross, F., editors, "Holography Marketplace: Fourth Edition", Ross Books, 1993 *Kluepfel, B., Rhody, A., Ross, F., editors, "Holography Marketplace: Fifth Edition", Ross Books, 1995 *Rhody, A., Ross, F., editors, "Holography Marketplace: Sixth Edition", Ross Books, 1997 *Rhody, A., Ross, F., editors, "Holography Marketplace: Seventh Edition", Ross Books, 1998 *Rhody, A., Ross, F., editors, "Holography Marketplace: Eigth Edition", Ross Books, 1999 ==Optics Books== *Popular Optics [[Popular Optics Review]] *Facets of Light [[Facets of Light Review]] *Seeing Light [[Seeing Light Review]] *Light Science [[Light Science Review]] 24deb9fc6bbd4df420e89da52eee5d14ede083e4 0 811 1609 1608 2013-05-12T04:07:54Z Jsfisher 1 1 revision wikitext text/x-wiki == Changelog for Ralcon Development Lab web page == I have stopped formally listing updates but there have been a few minor content changes as of&nbsp; Oct 2005, they include updating publications, patents and referrals to Wasatch Photonics plus a new picture of my lab and helicpter RDR<br> Prior changes listed below<br> ==== Changes since 4/8/1999. Most recent are at the top. ==== ---- ==== 1/8/02 ==== *Added a &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/files/Zone-SPIE2001.pdf"&gt;"Hoe Enhanced 355 nm Multichannel Direct Detection Lidar"&lt;/a&gt; paper. ---- ==== 4/4/01 ==== *Added a &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/files/DWDM-Dickson_grating_white_paper.pdf"&gt;"Dickson Grating White Paper"&lt;/a&gt; paper. ---- ==== 1/14/01 ==== *Put up the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/dichrohist.html"&gt;"History of Dichromates"&lt;/a&gt; page. *Rearranged home page. *Updated contact information. ---- ==== 9/13/00 ==== *Updated the "What's New" page. *Added another publication to the "Publications" page. *Added a few links to the "links" page. *Updated the "Experience" page. ---- ==== 5/12/00 ==== Tons of changes this time, although most of them weren't even large enough to warrent updating the "last modified" information. *Almost every page was updated to remove tags having to do with page color. *About half of the pages were updated to correct spelling errors. *The &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/circtpnt.html"&gt;Circle to point converters&lt;/a&gt; page was heavily modified, including a link to a new paper describing &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/circ_and_rot.html"&gt;Circle-to-point conversion and Optical rotary joints&lt;/a&gt;. *Behind the scenes, the site has been moved into a CVS archive. Hopefully this will help with keeping the page up to date. *A large list of &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/dcg-refs.html"&gt;DCG references&lt;/a&gt; was added. *Updates to the "holotools" page to reflect the new location of wxPython. ---- ==== 2/18/00 ==== *Updated the What's New page. *&lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/holotools.html"&gt;Holotools&lt;/a&gt; page now includes TIR2 written in Python for a cozy and simple GUI. ---- ==== 11/24/99 ==== *Added a &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/links.html"&gt;links&lt;/a&gt; page. *Updated the What's New page. *Added two publications to the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/publications.html"&gt;list&lt;/a&gt;. *Notified the world that Ralcon now has indoor plumbing *grin* *Fixed the "next", "contents", and "previous" images on the tutorial page (oops) ---- ==== 7/23/99 ==== *Added a page by Robert Rallison on &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/circtpnt.html"&gt;Circle to point converters&lt;/a&gt;. *Updated sitemap and home page to point to new page. ---- ==== 7/21/99 ==== It's been a long time since I made any changes, so I thought I'd make some big ones. *Major changes to the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/tutorial/index.html"&gt;tutorial&lt;/a&gt; page. All of the entries have been reordered, some of the images have been altered to make them more easily printed, and a "slide show" version of the tutorial is up. *A &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/hoebib.html"&gt;bibliography&lt;/a&gt; has been added. Right now it's just a set of &lt;pre&gt; tags around the very long list. *An updated &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/whatnew.html"&gt;What's New&lt;/a&gt; page is up. *Updated the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/sitemap.html"&gt;sitemap&lt;/a&gt; and home page to reflect changes. Also fixed a spelling error on the home page. No wonder no one has replied to our Employment "Opportunities" section. ---- ==== 6/18/99 ==== *Started a &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/tutorial/index.html"&gt;tutorial&lt;/a&gt; page. Right now most of the material is up, but it is out of order. It's fairly heavy on the images, but they're not big. ---- ==== 6/14/99 ==== *Added a new &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/publications.html"&gt;publication&lt;/a&gt; (the last one). *Removed the publications list from the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/resumes.html"&gt;about us&lt;/a&gt; page but left a link to the separate publications list. ---- ==== 6/8/99 ==== *&lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/main.html"&gt;contact/facilities&lt;/a&gt; page: **Minor cleanup. **Added more people to the contact information list. **Moved the facilities map to the same page. It didn't make much sense to have it on a separate page. *Removed outdated information from the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/whatnew.html"&gt;what's new&lt;/a&gt; page. *Minor changes to the main page (added a reference to "Employment Opportunities", which has always been in the What's New page, but never referenced. ---- ==== 6/3/99 ==== *Finished (mostly) the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/dcgprocess/index.html"&gt;"DCG and other phase materials"&lt;/a&gt; pages. ---- ==== 6/1/99 ==== *Fixed the broken image in &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/hybrid96.html"&gt;hybrid96&lt;/a&gt; and did some minor cleanup to the ALT tags. *Fixed the author information at the top of the page. *Alphabetized the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/sitemap.html"&gt;sitemap&lt;/a&gt; in a more reasonable manner. ---- ==== 5/24/99 ==== *Added a &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/sitemap.html"&gt;"Complete site map"&lt;/a&gt;. *Fixed lots of little bugs in various pages. ---- ==== 5/23/99 ==== *Updated the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/index.html"&gt;main index&lt;/a&gt; to point to the new pages. *Removed link to &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/old/about.html"&gt;"About This Web Page"&lt;/a&gt; page. It just didn't fit. ---- ==== 5/23/99 ==== *Added &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/hybrid96.html"&gt; "Wavelength compensation at 1.064µ using hybrid optics"&lt;/a&gt; page. ---- ==== 5/21/99 ==== *Started this changelog, including some earlier changes. ---- ==== 5/18/99 ==== *Spell checked everything (oops, should have done that a long time ago) ---- ==== 4/22/99 ==== *Fixed the area codes for the contact information (ooops). [Thanks Andres F. Zuluaga] ---- ==== 4/8/99 ==== *Updated the &lt;a href="http://web.archive.org/web/20080514035450/http://www.xmission.com/~ralcon/whatnew.html"&gt;"What's new"&lt;/a&gt; page for March through June 1999 <br> <br> ---- ---- [[Category:Rallison]] bdf3a936b9820e0c1fe536a7d866b3fa7af1f303 0 812 1611 1610 2013-05-12T04:07:54Z Jsfisher 1 1 revision wikitext text/x-wiki Doppler shifts in the optical spectrum may be detected either by heterodyne methods using coherent sources or by direct detection of filtered and dispersed return light. The coherent method requires diffraction limited optical trains and a local oscillator. The direct detection method is far more relaxed , requiring only "photon bucket" collection optics and a series of blocking filters and etalons to separate the frequency shifted light into a radial pattern. The direct detection of a Fabray-Perot pattern can best be done with a PMT or microchannel plate that has been constructed to have many equal area electrically isolated detection rings. Such a detector placed at the image plane can handle large fields of view and is good at preserving precious photons. A less expensive alternative would be a device that could effectively transform the output of the etalons into a string of foci spaced correctly to fit into a line of fibers or onto a linear CCD or photo diode array. This device could be called a circle-to-point converter and simply redirects all the rays that enter each of the circular annuluses into unique off axis focal points. One way to do this is to cut out annular sections of the edges of lenses and piece them together with appropriate offsets in their respective focal positions. An extension of this method would be to cut up plastic Fresnel lenses or diffractive lenses. These devices can also be thought of as fractured zone plates, re-assembled for the purpose of separating and detecting the Doppler shift imparted to a narrow frequency laser pulse by winds or moving objects. The increments in frequency occur in equal area annuluses so the coarse appearance of such an optic is that of a zone plate as well. The main purpose for this optical element is the remote detection of regional wind speeds. The same peculiar optical element constitutes a kind of rotary optical joint, useful in coupling wideband signals from a spinning platform to a stationary platform. In this alternative application the device is best made with each annulus being the same width rather than the same area. That would make it appear to be a coarse axicon rather than a coarse zone plate. Otherwise, they are or can be the very same optical element. Each annulus is simply an off axis focusing DOE or HOE that gets shifted laterally by some arbitrary increment between zones. We would change the way they are masked if shooting them in a step and repeat fashion and nothing else. Figure 1 shows a likely layout of the circle to point pattern and figure 2 is the corresponding rotary joint pattern. The circle to point pattern is used with full illumination over the aperture which has been made to have as many as 24 annular regions in a 25 mm diameter. The rotary joint would be used with individual modulated lasers or fibers addressing each zone with only a pencil beam. The number of channels would be limited by the size of the beams and the allowable crosstalk. The focus is shifted conveniently off the axis of rotation and out of the path of any zero order light in both applications. The method of fabrication and replication can be the same for each device. We made units with 24 zones as computer generated binary patterns recorded directly in photopolymer. They could also have been patterned into photo-resist and dry etched into silica. We opted to add a high frequency carrier to eliminate the possibility of cross talk from higher orders, alternatively a correct blaze could have been used at lower frequencies so that the parts could easily be fabricated by mechanical replication. We also made the same functional units by starting with a holographically constructed master which was subsequently stepped between exposures along with a mask of 7 or 24 rings. The HOE constructed this way can then be copied optically in one step into another volume recording material for higher volume production. [[Image:Difctp.gif|center]] <br> [[Image:Dorjoint.gif|center]]<br> == Acknowledgements == The diffractive design and fabrication of the rotary joints were carried out independently by Mathias Johansen and Sverker Hard at the Chalmers University of Technology in Sweden and the design of the circle to point converter was contributed by Matt McGill and others at Goddard Space Flight Center with fabrication being done at Ralcon development lab. Patents have been filed for or granted to both parties and both are deserving but I can't help being amused by the entirely coincidental invention of the same complex diffractive optical element for two widely differentiated applications. It makes me wonder how often such things occur. More details about each of these optical elements and the applications the were designed for can be found in the references and from the authors. Optical Interconnects is another field where similar devices may be used and could be searched for. It would not be a surprise to find the same device in the literature of that field and possibly also in holographic memories. == References == #Matthew J. McGill, M. Marzouk, V. S. Scott, J. D. Spinhirne &lt;Holographic circle- to-point converter with a particular application for Lidar work&gt; Opt. Eng. Vol 36 pp 2171-2175 Aug 1997. #Mathias Johansson, Sverker Hard &lt;Design, fabrication, and evaluation of a multichannel diffractive optic rotary joint&gt;, App Opt, vol 38, no. 8, pp 1302-1310, 10 Mar 1999. #R. D Rallison &lt;Fractured zone plates for spatial separation of frequencies&gt; SPIE vol 3633, pp 92-102, Diffractive and Holographic Elements, San Jose, CA, Jan 1999 <br> '''Last modified on 5/12/00''' [[Category:Rallison]] 708927cd9e645be48c5081b0cf0ce04c58289e01 0 813 1613 1612 2013-05-12T04:07:54Z Jsfisher 1 1 revision wikitext text/x-wiki [[Category:Rallison]] === A Simple How To === See the paper on ''Circle-to-point conversion and Optical rotary joints'' for more information. {| border="1" cellpadding="10" |- ! colspan="4" | Procedure |- ! Film Specs ! Exposure ! Processing ! Cap &amp; Grind |- valign="top" | Mixture: 10-30-350<br> Spin Speed: 88 rpm<br> Relative Humidity: 75% +<br> Incubation: 3 hrs<br> Temp: 96 deg F + | Wavelength: 488 nm<br> Copy Angle: -2 deg off normal<br> Exposure time: 55 sec for each ring<br> Energy in mj: 30<br> Room Humidity: 58%<br> Room Temp: 67 deg F<br> | Development: 45 sec.<br> Hot Alcohol Baths: 10 sec in each<br> Drying: Slow pull<br> Soaking: none required<br> | Glass: 7059 1/2 mm AR visible<br> Glue: NOA 61<br> Grinding notes: ground to 2" dia |} === Circle to Point Converter Setup and Alignment Procedure === ==== Preliminary Inspection ==== *Verify that all of the stepper motors and controllers are connected properly and that the appropriate relays are connected to their respective devises. *Verify that when using toggling of relays in the script, that no toggles in the script are missed. A toggle is used to close the relay, but another toggle is required to open it again. ==== Alignment ==== To align the mask, you must choose a reference point and align it to that reference. The reference is the stage that the mask is clamped against. The two stages that make up the X and Y axes must be orthogonal. If the laser is focused on the mask and a detector is placed under the mask, a measurement of the power from the laser can be obtained. By moving the Y stage in small increments, you can cut the laser power with the mask. Continue to move the Y stage until the detector is in the 50% power range. Any fluctuation in the power can the be monitored as you move the X stage back and forth. When the mask is aligned, minimal power fluctuation should be seen along the entire length of the mask. This is observed by simply moving the mask with the X stage control and watching the power monitor. The mask must be in it's resting position, therefor the film holder must be out of the way so as not to scratch the bottom of the mask. An alternate method of aligning the mask is to use the laser "knife test". This involves a similar method of focusing the laser to one of the X edges of the mask. The preliminary adjustment is to make the laser orthogonal to the surface of the glass. This is easily done with a mirror placed on the surface of the mask for reflection. When the beam is reflected directly back into the laser, normal incidence with the mask has been achieved. Once the laser's focal point is close to the surface of the mask, which is at the bottom of the glass, the Y axis can be moved to count the number of micron steps are required to block out the laser. By adjusting the laser in the Z direction, you can then continue this process until you are at the focal point of the laser, which is at the point where the laser can be shut out and allowed to transmit with the smallest number of steps by the Y stage. When at the focal point, the laser should be able to be completely shuttered with approximately 30 microns of movement of the Y stage. The stage controllers display the magnitude of the movement in an obvious fashion. Also, the laser should always be oriented in a manner that allows the smallest portion of the beam to be orthogonal with the edge that is being aligned. By simply moving the laser to another edge, orthogonality with the stages can also be measured. This same method is used in making the stages orthogonal in the preliminary portion of this entire setup. ==== Parallelism ==== The stage top, the mask, film holder, and master hologram must be parallel. In order to achieve this, you must use a spatial filter, a collimating mirror, and several other mirrors. A mirror should be placed on each surface that needs to be parallelized. The light must be collimated with a collimating mirror in line after the spatial filter. The mirror on the surface of the reference plane is the first used. By directing the beam down to this reference mirror and adjusting the deflecting mirror, the beam can achieve normal incidence with the reference surface. By placing a white board next to the spatial filter, you can then adjust the same deflecting mirror such that the reflected beam is off axis. This gives you a reference point for all of the other surfaces. Now, with a large collimated beam, you can see the reflected points of all of the surfaces, and simply shim them until all beams lie in the same spot on the white board. This verifies the parallelism of the different surfaces. ==== Master alignment ==== Whereas the master is in place over the mask, and must be swung out of position between each piece of film that is being exposed, it is difficult to make it exactly parallel with the masks Y edge. A square can be used to get this as close as possible as far as alignment is concerned. As far a parallelism with the surface of the mask and film, the section on parallelism explains the process to achieve this. ==== Making the Mask Lie Flat Against the Film ==== A feeler gauge should be used to test the width of the mask and film separation on all sides of the film. The mask should be moved to all extremes and the test should be repeated until all places on the mask have similar tolerance. The mask must make contact with the film or shadow will occur. The film holder has a rotational adjustment to move the film in the Z direction. After the surface of the film and the mask are parallel, this adjustment will allow the mask to lie flat against the film in all positions of the exposure. ==== DCG (DiChromated Gelatin) Film ==== With DCG film, an exposure energy of approximately 20-25 mJ should be used. Older film may require more energy to be exposed properly. An index matching material such as Decahydranaptholine should also be used. This not only acts as an index match, but it also holds the film in place by creating a vacuum effect between the film holder and the film. The exposure is followed with a development time of the following: *Developer: 45 sec. *Rinse #1: dip *Rinse #2: dip *Rinse #3: dip *Alcohol #1: 10 sec. *Alcohol #2: 10 sec. *Alcohol #3: 10 sec. ==== Optical Setup for Exposure ==== In order to expose the rings on the mask, the beam needs to be larger than the largest ring and centered on the ring. The power of the beam should be uniformly distributed also. First the beam should be at normal incidence with the mask. This is accomplished by adjusting the reflected beam to lie directly on the beam of origin. Once this is achieved, the 2.5 degree adjustment in the angle of incidence is easily obtained. A mirror with an angular measure on it's adjustment is used. The mirror is then adjusted such that the beam has a negative 2.5 degree incidence with the mask. At this point the mirror may need to be adjusted toward the beam that is coming from the collimating mirror so that the spot is centered on the rings. Any portion of the beam that is larger than necessary should be masked. The optical path from the laser is as follows: the beam from the laser is sent though a spatial filter and into a collimating mirror. The beam is then directed down to the mask with the mirror that has the angular adjustment measure. Between the collimating mirror and the mirror that directs the beam down to the mask should be the extra mask that makes the spot the correct shape and size for the exposure. ==== Removal of Mask ==== The mask holder should have the mask attached to it in a secure manner and aligned with the rest of the system as stated in the alignment section of the instructions. Now, between exposures, the mask holder with the mask can be removed and replaced in a precise way. Whereas the mask holder is fastened to the base with a single spring bolt, it can be easily removed. The spring bolt holds the balls on the mask holder into the sockets in the base. After removing the mask holder, the film can be placed on the film holder and the mask holder is then replaced. After tightening the screw slightly, enough to hold the balls securely in the sockets, the mask holder should be cycled up and down to ensure that it is in place. A realignment is not necessary if the mask holder is removed and replaced in this fashion. The mask holder should be handled with much care because if the mask is moved even slightly within the holder, a realignment would be necessary. To cycle the mask up and down, simply pull the pin into the solenoid manually and then let the mask lie back down gently. The mask should be cycled several times each time the mask holder is removed from the base. === Using the Scripting Language === ==== Script Format ==== *The script must be written in ASCII DOS text without comments or any extra spacing. *Line 1: Number 1-5 that represents the current number of stages to control. *Line 2: Unique address, number 0-31, for each stage. Addresses should be separated by a single space only. *Line 3: Number of times to repeat the entire instruction set. Lines 4-200: These are the lines that control the stage movement and the relay actuator. *Each line is either a relay control, or a stage control. For a stage control, the fields represent stage address (previously specified), number of steps, and a delay time or pause (number in milliseconds or "p" for pause). These fields are also separated by a space. *For a relay control, the fields represent relay control ("r"), relay number (0-7), and time in milliseconds for relay to be closed. ==== Sample Script ==== The data will be entered in this manner (without comments), starting on line one. {| |- | 3 | ''This is the number of stages to be controlled.'' |- | 6 9 10 | ''These are the unique addresses of the stages.'' |- | 2 | ''This is the number of times to repeat the entire script that follows.'' |- | 9 100 p | ''Move stage at address 9 100 steps and wait for user input "c" to continue.'' |- | r 2 2000 | ''Control Relay number 2, close for 2 seconds.'' |- | 6 100 1000 | ''Move stage at address 6 100 steps and wait 1 second before continuing.'' |- | r 7 2000 | ''Control Relay number 7, close for 2 seconds.'' |- | 10 31000 2000 | ''Move stage 10 31000 steps and wait 2 seconds before continuing.'' |- | r 0 30000 | ''Control Relay number 0, close for 30 seconds.'' |} ==== Software Limitations ==== *Currently only five stages can be controlled at the same time with the program. *As specified by the IEEE 488, the addresses of the stages must be unique and be within the range of 0-31. *The program will only accommodate 200 lines of code in the script. This infers that only 197 control instructions may be loaded by the program. *The number of repetitions of the execution of the entire script is limited to 32000 times. *A line is limited to 80 characters. *All fields must be separated by only a single space. *Time must be entered in milliseconds. *The character "r" must start the line of any relay controlling command. *Currently only 8 relays can be controlled with the program, numbered from 0 - 7. *When "p" is entered in the delay time field of the stage controlling command, the key "c" must be pressed in order to continue with the script. *Steps are limited to the range from -32000 to 32000. *Most of the stages have a one micron resolution, giving steps of one micron. For other stages with different resolutions, the step size will change. The user must modify the script for any differences in stage resolution. *The relay control portion of this program is only accurate down to approximately ten milliseconds. This constraint is a result of the parallel port communication with the relay actuator. ==== Hot Alcohol Bath (HAB) Specs ==== <center> {| border="1" cellpadding="5" |- ! # ! Temp in F ! Specific Gravity |- valign="top" | HAB1<br> HAB2<br> HAB3 | 135 deg<br> 135 deg<br> 135 deg | .86<br> .76<br> .75 |} </center> ==== Table Setup ==== [[Image:Circtpnt.gif|center]] ==== Stepper Setup ==== [[Image:Pic19.jpg]]<br> <br> ==== Testing ==== [[Image:Testing.gif]] '''''Last modified on 5/12/00''''' 52d54bad3cf61f3ae174fc8a3099af8be3206207 0 193 1615 234 2013-05-12T04:07:55Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Colink.jpg]] Colin Kaminski is an amateur holographer who in a state of extreme frustration and needing advice started the forum that has become the [http://www.holographyforum.org Holography Forum] and now this Wiki. He really has no other holography releated acomplishments other than about 100 or so 4x5" and smaller holograms given to children. He has worked as an Assembly Language Programmer, Motorcycle Mechanic, Luthier, Theatrical Lighting Designer, Product Designer and now he is the Master Brewer at [http://www.downtownjoes.com Downtown Joe's] in Napa, CA. [http://www.designerinlight.com Colin Kaminski's Web Site] [[Image:Colinemail.gif]] b5f991a712c1fd534d9906ff0fc3b63ac38f6899 0 814 1617 1616 2013-05-12T04:07:55Z Jsfisher 1 1 revision wikitext text/x-wiki * [[Additional use for Fringe Locker | Additional use for Fringe Locker]] * [[Bibliography | Bibliography]] * [[Blazed binary optics, from pc to plastic | Blazed Binary Optics, From PC to Plastic]] * [[Changelog for Ralcon Development Lab web page]] * [[Circle To Point Converters]] * [[Circle-to-point conversion and Optical rotary joints]] * [[Contact Information, Facilities, Materials, and Ordering Information]] * [[Control of DCG and non silver holographic materials]] * [[DCG References]] * [[History of Dichromates]] * [[Directional Diffusers]] * [[Equations | Dirrectional Equations]] * [[Resume of Richard D. Rallison | Experience (Resume)]] * [[Fringe Locking]] * [[About Ralcon Development Labs | General Information About Ralcon Development Labs]] * [[HOE Kit | HOE Kit Information]] * [[Hoes and Does | Hoes and Does Information]] * [[Holotool Contents | Holotools]] * [[Index for DCG and other phase materials]] * [[Instructions for Getting Here]] * [[Links]] * [[Polarization properties of gelatin holograms]] * [[2 and 3 Color Dichromates | Pseudo-color Techniques]] * [[Publications]] * [[Ralcon Development Lab | Main page]] * [[Recording Material Selection]] * [[Stability Issues in DCG]] * [[Time Reverse Ray Tracing]] * [[HOE Tutorial | Tutorial]] * [[VHOE Relationships]] * [[Wavelength compensation at 1.064µ using hybrid optics]] * [[What's Happening]] * [[Zone Plate Equations]] ''Last modified on 1/14/01'' [[Category:Rallison]] d7fd3358bc5c793ed0f2666cb2d7e1f13a98b54e 0 815 1619 1618 2013-05-12T04:07:55Z Jsfisher 1 1 revision wikitext text/x-wiki [[Category:Rallison]] == Materials == Available volume holographic recording materials include &lt;a href="http://web.archive.org/web/20080720014742/http://www.xmission.com/~ralcon/dcgprocess/index.html"&gt;DCG, SHG, PVA, assorted Photopolymers&lt;/a&gt;, and Kodak, Agfa and Ilford products. The DCG formulations include thicknesses from 4 to 50 microns, color control from 650 to 450 nm and &lt;a href="http://web.archive.org/web/20080720014742/http://www.xmission.com/~ralcon/phasemat.html#indexmod"&gt;index modulations&lt;/a&gt; up to .25 with a strong chirp and gradient. All other materials have properties that fall within the range of DCG formulations and are selected for sensitometric or environmental stability reasons as needed. Photo resist for surface diffraction has been added to make DOEs in glass, epoxy, and plastics. == Facilities == [[Image:Map.gif|right]]The development lab is a modest 8000 sq. feet and located in a remote corner of a high mountain valley in northern Utah. The solitude is convenient for long exposures in dichromated gelatin (DCG) or photo resist and the humidity is typically low. Salt Lake International Airport is little more than an hour away and skiing is close by.<br> == Ordering == As of 2004 all orders first have to be weighed as commercially viable or just an experiment and if there is a commercial potential the order will likely be handled by Wasatch Photonics http://www.wasatchphotonics.com/index.html&nbsp; I am now alone and can only do a few tasks in my own lab, which has been closed to all commercial activity by Cache County.&nbsp; We accept phone, fax, credit card and E-mail orders and will quote verbally for simple gratings and reflectors of up to about 20 square inches. More complex devices require drawings and written specs. Simple optics take 1 to 4 weeks, complex devices run 2 to 6 months. All orders are run in batches with a minimum cost of $500 for either masters or copies. Typical minimum deliverable batch results are three to six units. Costs for simple optics are strongly affected by tolerances, testing and finishing requirements. Costs for complex projects are affected additionally by design time, tooling, component purchases, masters sub-masters, transfers, &lt;a href="http://web.archive.org/web/20080720014742/http://www.xmission.com/~ralcon/hybrid96.html"&gt;wavelength compensations&lt;/a&gt;, diffraction limited performance, size and substrate materials. We can work on a cost plus fee or fixed price basis, some work may require that we do best effort only. Tooling and purchased parts may have to be paid for in advance. Terms are negotiable and normally net 30, but larger projects require incremental progress payments. For inquiries of any kind call or &lt;a href="http://web.archive.org/web/20080720014742/http://www.xmission.com/~ralcon/main.html#contact"&gt;contact&lt;/a&gt; the lab director == Contact Information == &lt;address&gt;Box 142<br> Paradise, Utah 84328-0142<br> Phone: 435-245-4623<br> FAX: 435-245-0507<br> Cell: 435-770-8480<br> Email: rdr@ralcon.com &lt;/address&gt; &lt;tbody&gt; &lt;/tbody&gt; {| border="1" cellpadding="10" |- ! Lab Director: ! Lab Technicians: |- valign="top" | &lt;a href="mailto:rdr@ralcon.com"&gt;Richard Rallison, PhD.&lt;/a&gt; | &lt;a href="mailto:robrallison@wasatchphotonics.com"&gt;Robert Rallison&lt;/a&gt;<br> |} <br> '''''Last modified on 1/14/01''''' <br> 75a710dd135a409d3253d93af3687fb849c0cc37 0 816 1621 1620 2013-05-12T04:07:56Z Jsfisher 1 1 revision wikitext text/x-wiki === ABSTRACT === We review the properties and relative usefulness of 3 non silver Volume holographic recording materials that are available today. Dichromated Gelatin (DCG) will receive the most attention followed by Dupont Omnidex products and a light treatment of Polyvinyl Carbazole (PVK). Enhancement and control of color, bandwidth and diffraction efficiency of volume reflection holograms recorded in DCG and photopolymers is discussed. Methods of increasing the bandwidth while shifting the center frequency toward the red is given for photopolymers. Red pseudo color will be covered thoroughly so that the practitioner will have all the elementary tools to make full color and broadband DCG holograms from scratch. The entire DCG technology is disclosed as it relates to production of high quality display holograms that span the spectrum and may be narrowband and very deep or shallow and broadband. === MATERIAL === The list of volume holographic recording materials includes the silver halide films, photopolymers, photocrosslinkers, photochromics, ferroelectric crystals and a few less well known oddities. While useful devices may be made in all these materials only a few will provide a holographer with a sufficiently high index modulation, resolution, signal to noise ratio, spectral response, and archival properties. The silver halide films have grain size limited resolution, scatter short wavelengths excessively, have only a moderate index modulation and tend to print out in UV light. They are popular for many applications because they can be made panchromatic, are much more sensitive than any other materials and are commercially available. We ocassionally use silver halide films to make master holograms and we reduce the blue scatter by converting them to a gelatin hologram (SHG). Used in this manner they are nearly equivalent to dichromated gelatin (DCG). They enable the production of DCG masters shot with red light at silver speeds that can be copied with green light in DCG and reconstructed finally at the original red color. SHG processes are covered in previous publications. The three materials detailed in this paper were chosen because they each have more or less all the properties needed for the construction of high quality or high efficiency broadband or narrowband color controlled holograms. They are not without faults however and the purpose of this work is to provide information to a holographer to assist him to make a better material choice for a particular task or to set up for production in DCG. Some information is given relating to the peculiar drop in average index in DCG, PVK and DMP128 due to the nature of the index modulation in these materials. Very thick coatings, up to about 50 microns are also dealt with in a special section. Comments made about preparation, processing, fine tuning, protection and applications are based on many years of working with DCG and many months of working with the other two materials, Dupont's Omnidex materials and Polyvinyl Carbazole (PVK). DMP 128 is another well documented material. It is a proprietary Polaroid formulation of lithium acrylate in combination with a branched polyethylenimine. Although it is not generally available commercially Polaroid has allowed laboratory evaluations and it is now quite common to get holograms mass produced in the material at Polaroid. Several other photopolymer systems are possibilities for holographic work but these 3 represent the readily available and practical recording materials of the day. === REFLECTION HOLOGRAM FABRICATION STEPS === ==== Mixing and coating ==== DCG is a mixture of Ammonium dichromate, gelatin and water. It is stirred together, heated, filtered and spun on or drawn down with a bar. Drying with or without heat from gel or liquid states makes little difference. Bright yellow lights are permissable. A 10 micron film can be made by mixing one gram dichromate with 3 grams of gelatin and 20 grams of water and spinning a flooded 8x10 glass plate at about 80 RPM. The solution and the coated plate is useful for about 3 days, much longer with refrigeration. PVK is dissolved in chlorobenzene along with Carbon tetraiodide, it is difficult to get into solution even with heat and agitation. It is also very unstable and may gel in as little as 15 minutes after mixing. The solution may be further thinned for convenient spinning but is easily applied with a bar. A number 28 bar will yield a 5 - 7 micron coating when 2 grams of PVK are dissolved in 25 grams of chlorobenzene. The patent disclosure mentions nothing about mixing the sensitizer with the PVK while still dry but if this is not done the solution will likely not be photosensitive. The solution will usually remain stable enough for coating for about 1 hour after mixing. The coated substrate is good for at least 8 hours. Dupont's materials can be purchased already to use on plastic substrates or may be obtained in liquid form for coating by any of the techniques covered here. ==== Storage after coating ==== DCG stores well at low humidity in a refrigerator or freezer but containers must prevent contamination, condensation, freezer burn and frost which can all destroy surface quality. Film of 10 to 20 microns or more store best and are good for at least a year. At room temperature and 50% RH, thin films are good for a few hours, thick films typically last a week or more. The addition of a small quantity of TMG to the mixture will greatly increase storage time at room temperature by increasing the PH. PVK does not store well as a rule, sometimes it has lasted a week in the refrigerator. Typically it moves suddenly to insensitivity within 24 hours and it does not seem to age gradually. The instabilities in coating and storing could be alleviated by adding more antioxidants to retard the spontaneous formation of free radicals but at the cost of reduced photo sensitivity. Dupont's materials seem to store well under refrigeration for a year or more depending on type, their newest film is also very sensitive, requiring only a few mj/cm*cm to expose in red or green. ==== Exposure characteristics ==== DCG is most sensitive in a hot moist environment. At 50% RH and 68 degrees F it may require 60 mj/cm*cm of 488 nm light, while at 75% RH and 80 F 4mj/cm will do the same job. At 441 nm less than 1 mj is enough and at 514 or 532, 50 to 100 may be necessary. The percentage of dichromate affects speed more or less linearly, a 25% mixture is typical but mixtures of from 10 to 30 percent are necessary to control color. Gross overexposure will cause a decrease in efficiency all the way to zero. Overexposure causes an initial increase then a decrease in bandwidth and a blue shift plus a compression of contrast or dynamic range. PVK is totally insensitive to moisture, water can be used as an index matching fluid with no effect on the hologram. It requires about 20 mj/cm*cm at 488 nm to make a good single beam reflection hologram and because it is a cross linker it can be overexposed. Over exposure also results in a blue shift, a wider, then narrower bandwidth and loss of contrast. The Dupont material is a real time material and as a result can interfere with itself during an exposure. As the hologram is forming it is also reconstructing and making small dimensional changes. The results can be that at some time during an exposure the reconstruction could be out of phase with the construction momentarily. The energy required varies from about 8 mj/cm*cm to a 100 or so mj. It has good resistance to water and readable holograms have been made by us in 100ms. ==== Processing procedures ==== DCG is hardened briefly in Kodak Fixer with hardener then rinsed and plunged into several hot or cool alcohol baths. Cool baths produce better uniformity and lower noise, hot baths can yield tremendous index modulations with large chirps in Bragg spacing but often with increased noise. Depending on the mixtures, temperatures and times spent in each bath, a wide range of effects can be had. Processing and reprocessing affects bandwidth and center frequency over 100 nm or more and index modulation can be varied from near nothing to .25. If the first pass in the baths produces a shift to red, a second pass can shift it to blue and a 100 nm bandwidth can be reprocessed to yield a 30 nm bandwidth. Typically "master" holograms are processed to construct near the recording wavelength but processing and dichromate content allow the control of color to range from 650 to 450 nm for a straight on exposure at 488 nm. This much versatility in color control is certainly useful and will be covered in more detail. Conformal mirrors on flat substrates can be color shifted easily with angle but more complex shapes must be tuned with processing and film formula juggling. As an example of a reprocessing procedure, a red shifted broadband mirror may be narrowed and blue shifted by agitation for 30 seconds in a room temp 50:50 mixture of water and alcohol then plunged into 99% hot alcohol with agitation for 30 seconds and pulled slowly from the hot bath. The direction of the shift can be controlled by the ratio of alcohol and water in the first bath and the amount of shift can be controlled by the time in the same bath. A near ideal tuning bath has a specific gravity of .86 when it is warmed to about 55 degrees C. This process can be repeated many times if necessary, especially if the last hot bath is not hot enough to cause excessive scattering center buildup. Multiple buffer baths between the first color control bath and the last dehydration bath help to keep the last bath clean. PVK is swollen in Xylene or Toluene for a few seconds then dried in warm Hexanes or Hexanes mixed with alcohols. Like DCG the latent image must be enhanced by swelling in the first solvent and then replacing that solvent with a miscible but nonswelling solvent. Again, color and modulation control is by temperature and time. Color control is similar to DCG methods and either broadband red shifts or narrowband blue shifts are possible by altering time and temperature. Reprocessing is possible but scattering centers build up rather quickly in this material. The first solvent probably dissolves away material as it causes swelling. Signal to noise is usually good in narrow band processing but not so good for broadband reconstructions. A recent proprietary improvement in processing involves the use of a clever monobath made up of two miscible solvents. One of the solvents will swell the PVK and is more volatile than the other solvent which will not soften or swell the PVK. The most volatile solvent evaporates first and leaves the hologram structure in rigid uniform shape while the second solvent is driven out with warm dry air. Dupont films are developed with UV light and heat. They may then be brightened and color shifted by the addition of monomers and or solvents. It is common practice to laminate a cover glass over gelatin holograms to protect them from moisture, abrasion and chemicals. Many common epoxies have been identified as safe for this purpose as well as a broad class of adhesives described as UV polymerizable substances,( monomers, epoxies, resins, adhesives, etc). I accidentally caused an enhancement of several photopolymer holograms while attempting to laminate them. In one case the bandwidth widened from 40 nm to 150 nm and the optical density remained almost as high as the original structure. The photopolymers behave a little like sponges that can be dampened and swollen or alternatively soaked and saturated while the shock dried DCG and PVK structures are more like a stack of Ruffles potato chips that get damp, go limp and then collapse. Enhancement of Dupont photopolymer is the easiest and most reliable. The holograms produced from blue exposures originally playback blue but the enhanced holograms playback at a longer wavelength and are noticeably brighter. Solvents alone brighten and shift the reconstructions to the red but they are temporary treatments and not generally as effective as UV curable monomer type adhesives. A Dupont product is now available to make predictable shifts in playback color. They provide a monomer on a cover sheet that will diffuse into the exposed film where it causes swelling and can then be fixed by polymerization under a UV source. Some Dupont film reflection holograms will respond to the following recipe with a red shift and increase in total diffracted energy. Apply Lightweld 401 evenly and cover then wait for a color change and cure with strong UV source. If this substance is left uncured it may destroy the original structure. It is also anaerobic and therefore requires a cover to cure. ==== Protection ==== DCG is notoriously bad at remaining stable in normal environments. Moisture will cause the Bragg structure to collapse and the gelatin grabs moisture easily from the air right through most plastics and glue. This material usually requires lamination between glass with enough gelatin removed around the edges to form an "O" ring seal. Thick plastics, such as 30 mil mylar, will also work and certain fluorinated plastics such as "Aclar" in thin 5 mill layers are satisfactory provided that the edges have been cleared of gelatin before laminating. PVK needs protection from abrasion but it stands alone as the only holographic material we ever worked with that is completely waterproof. It requires only a 4 mil mylar laminate for adequate abrasion protection from the environment. Dupont's materials may be used as is or uncovered and rolled down onto a glass substrate. They need very little protection after being fully polymerized with UV light but a stiff flat backing helps with image distortion. Water can affect them temporarily but the structure is essentially humidity proof. === APPLICATION NOTES === DCG is easily the most versatile material, just about any kind of HOE or hologram can be made in it. Unfortunately it has poor environmental stability and must be well protected or it may not be intact when you need it. As long as glass or thick plastic is acceptable in the finished product DCG is the number one choice. With some difficulty it can be made panchromatic for full color work and under warm moist conditions it is a little more sensitive than the other two in the blue-green region. The SHG versions are much more sensitive and represent the only fast "non silver" medium useful for pulse holography applications. PVK is not so pleasant to work with as DCG but it goes onto plastic substrates easily, has a high delta n and needs only minimal protection. It should be very good for such things as eyewear, solar collection and other outdoor applications or anyplace where superb environmental stability is required. Dupont's materials come with an ever wider range of properties. They are durable and panchromatic but lack a little in dynamic range. The maximum available index modulation is lower than the other two materials and display holograms are typically less bright. Initially we tried to determine the index modulation of simple reflectors made in each material by fitting them to the simple one dimensional Kogelnick expression for diffraction efficiency (D.E.) of reflection volume holograms. {| border="1" |- ! colspan="2" | Kogelnick Expression |- | <math> DE = \tanh^2 \, {{\pi\Delta n T} \over {\lambda\sin\Theta}} </math> | Where *T = thickness of material in microns *λ = .5 microns (typical) *sin θ = 1 (for conformal mirror) |} This relationship seldom describes real reflection structures because it does not describe the effects of a gradient on the index modulation (delta n) or a chirp in the grating spacing (d). A gradient in delta n such as is caused by the absorption of light by the sensitizing dye results in a smooth broadening of the angular and spectral bandwidths and a smoothing of sideband peaks (when DE is held constant.) A chirp in the Bragg plane spacing also broadens the bandwidth though not so smoothly and the combination produces a highly asymmetric spectral bandwidth. The data and a description of the computer model is given in a previous publication. All three materials exhibit a useful range of index modulation and color control and each has found multiple commercial uses. The differences lie mainly in sensitometric characteristics, environmental stability and in the degree of difficulty to obtain or use. The balance of this paper will detail the use of DCG. We will try to give instructions that can be followed by anyone that is already familiar with more conventional holographic fabrication techniques and materials. Some details are left out for the sake of brevity but can be found elsewhere in the references or other literature. === SPIN COATING APPARATUS === A variable speed turntable capable of 50 to 100 RPM will coat films of gelatin or PVK from 4 to 50 microns on 8 x 10 inch glass or plastic substrates. Plates as small as 3 inch diameter or as large as 16 x 16 inches have also been successfully coated with this range and technique. The turntable should be equipped with a surface or arms that will mate to a removable tray that is one or two inches larger than the substrates being coated. We have used ordinary variable speed phonograph players with pie tins turned upside down and glued to the turntables and we have used Dayton variable speed gear motors with heavy duty arms attached. Both devices worked very well. Trays have been made up of stainless steel, plexiglass, polyethylene dishpans or modified from aluminum cake and pizza pans. The best trays have straight sides measuring 2 1/2 to 4 inches high and are fitted with 3 rubber posts inside and outside. The posts inside hold the substrate an inch or so off the bottom of the tray and the outside posts serve to level the tray during pouring of solutions and to center the tray during spinning. The spinning tray and substrate may generate useful turbulence that aids in drying and distributing the solution. Excess solution is caught in the tray and emptied between substrates then is easily soaked clean in hot water after a days activities. An important component that augments drying and uniformity is the blower-heater. It hangs off center and above the whirling tray. Turbulence and heat combine to make uniform coatings in about five minutes. We recommend the use of a variable temperature 600 watt blower such as might be found in the ceilings of some bathrooms. A little experimenting with angle and position will quickly determine the best place to hang this unit in your clean hood or bench area. Coat and examine uniformity by looking for local fringe patterns under a fluorescent lamp or better yet a fluorescent long wave black light. === BAR COATING APPARATUS === Lab coating bars are available from R.D. Specialty Co. in Webster N.Y. Ph (716)265-0220. A selection of bar types may be purchased for about $ 50.00. We have used bars of 3/8" diameter wound with # 24 wire as a standard but we have other windings and diameters on hand for special applications and recommend you do the same. These bars are also useful for applying strippable coatings for anti halo backings, and have been used for coating photopolymers and protective epoxy layers etc. Jigging for bar coating can be as simple as a clipboard with lint free paper placed under the substrate. A better jig is one that holds the plate above a trough that can catch run-off. The whole thing can be plexiglass which is particularly easy to get gelatin off of and it also preferentially over glass attracts dust particles. Bar or spin coating is done in a class 100 environment and is accomplished by pouring out a line of solution and pulling it down with a uniform pressure and velocity. A little practice will determine correct amount of solution, speed and pressure. The bar is not rotated as it is pulled and a new location or freshly cleaned and dried bar is used on each new substrate. Variations in thickness may be accomplished by changing wire size or viscosity or both. Precautions must be taken to keep the bars clean and undamaged. We place used bars in warm water and rinse and dry them before each use. A rack that holds them suspended above any surfaces is useful for storage, cleaning and serial use. It can be made from plastics or metals. Coated plates need to be placed in a level position where they can air dry in a few minutes. The coating jig should be nominally level. Cronar, (polyester) substrates are easily coated with these bars. Cronar is a Dupont product. One source is Farrest Chemical &amp; Supply, 680 Toland St., San Francisco, CA (415)8241400. It is available in sheets (C-42) or rolls (C-41) in a variety of sizes. Exposure of Cronar is done with a thick glass vacuum chuck or by humidifying the gelatin and rolling it against a clean glass plate. It is optically active and you may need to identify its neutral optical axis before exposure. Processing is best done by stretching it in a frame for dipping and agitation or by clipping it flush to a glass substrate fitted with a handle on one side. === FILM PREPARATION === Many factors need to be considered when mixing DCG for holographic film. ==== Jelly strength ==== The jelly strength, measured with the Bloom Gelometer, is an important consideration. The current gelatin being used by us for film production is either MCB brand (Mattheson, Coleman, and Bell Manufacturing Chemists, Norwood, OH 45212 # GX-45' OH 45212) # GX-45. Grayslake Type B USP XXIII Box 248 Grayslake,IL . 60030 Phone (312) 223-8141 Contact Bob Buscher. Both gelatins have bloom strengths from 215-235. Comparable with the jelly strength is the rated solubility of the gelatin, and the mode of manufacturing. (Acid or Alkaline processed.) These can each make a considerable difference in the quality for each lot. It is best to test every specific lot before final acceptance of a gelatin. Perhaps the best rating for gelatin to be used for DCG is the jelly strength-to-viscosity ratio. A ratio of at least 4 or 5 to 1 is considered good. Our current batch has a bloom of 232 grams, a viscosity of 42 mps and a ph of 5.1. ==== Heating ==== One important caution when preparing the DCG film mixture is the destabilization of the gelatin at high temperature. When heated for an excessive period of time, the film breaks up, causing what we term as film "pits" in the final emulsion. These "pits" have the appearance of small circles of various sizes and scatter themselves throughout the plate. When the film is processed, the final image has small voids where the "pits" were. So far, the length of the heating time and the peak temperature that cause this have not been determined. In the past, temperature and heating time causing this have fluctuated. But the safe method is to heat the film mixture at the shortest possible heating time to dissolve the gelatin content completely. 130 F to 150 F (60 C.) is usually a high enough temperature to dissolve without cooking. Gelatin "melts" around 40 to 45 C. The causes of film "pitting" are still unknown to us as well as what the "pits" really are. But their characteristics (and that of gelatin) can give us some ideas. It is important to take all known preventative measures for keeping them off the emulsion. Triple filtering helps and avoiding hot spots while mixing helps. We use a standard mag stir hot plate and glass flasks which are heated slowly while stirring or heated in a water bath, a microwave oven has also worked well using plastic bottles . Film "pitting", or destabilization, in the past, has seemed to be affected by the solubility of the gelatin. The higher the solubility, the less likely film "pits" occurred. The solubility, of course, is slightly affected by jelly strength and impurities. Literature within the gelatin film industry indicates temperature separation may occur, partly due to the polysaccharide content of the gelatin. There is one speculation of film pits which involves the crystallinity function in drying films. (And this is a function of film temperature.) The other theory for film "pits" is the presence of insoluble impurities (such as arsenic, grease, etc.) on the surface of the film. These substances probably conglomerate during mixing and heating to make larger hydrophobic areas on the glass. Surfactants would alleviate this but they aggravate adhesion problems as well. ==== Water ==== Use deionized water for the DCG film mixture. It eliminates certain salts which have produced inconsistencies in film behavior. Distilled water is also acceptable. Any water should be funnel filtered through a 5 micron or smaller filter and be free of oil, grease, and bacteria that thrive on gelatin. ==== Storage ==== Film mixtures may be stored in a refrigerator for a week or two and reheated in water or a microwave oven as needed. When stored longer the become less and less likely to flow when warmed. ==== Film codes ==== The film mixtures vary in dichromate and gelatin percentages. The variations depend on the specific use that a DCG film plate has. The film code currently used contains three numbers. The first being the gram-weight of the ammonium dichromate, the second being the gram-weight of the gelatin, and the third being the gram-weight (mls) of the water to be used in the film mixture. (Usually mixed in a 500 ml poly bottle.) The code for film used in broadband image holograms is 8-30-350. Thus, 8 grams dichromate, 30 grams gelatine, and 350 grams (mls) of water are mixed together. The mixture code for "red" holograms is 3-30-200. Most holographic optics are made in 10-30-250 to 8-30-150. Very thick coatings of 30 to 50 microns can be made using a 3-30-125 mixture but special fixturing may have to be made to get the gelatin to flow uniformly and the dried film may come off the substrate unless it is baked on at high humidity. We find adhesion is enhanced by cleaning the substrate in clorox and then baking the coated plate at 130 degree F in the presense of water at saturation. In using the film code for a variety of mixtures, the 30-gram gelatin weight number always remains constant. Thus, when a thicker emulsion is desired, the water number decreases. And when more absorption is desired, the dichromate number increases, an increase in thickness narrows the bandwidth and an increase in dichromate shifts the color toward the blue. As a general rule, thicker emulsions require longer process times but are easier to make uniform. The dichromate concentration determines light absorption and the center reconstruction wavelength of the hologram. For higher dichromate concentrations, the increased absorption produces larger gradients of index modulation. Lower the dichromate concentrations produce more uniform index modulations. Larger gradients yield slightly larger bandwidths and the removal of higher percentages of dichromate during processing results in thinner and thus bluer holograms. When a specific bandwidth is desired, along with a specific reconstruction wavelength; it is best to experiment with various film mixtures. Usually starting with a standard mixture and then adjusting the thickness, and dichromate content to achieve the desired results. The color controllability and uniformity of DCG film improves with thicker film emulsions. Consequently, they are more forgiving in their exposing and developing parameters. Extremely thick (25 micron or more) emulsions ( X-30-150, a 5 to 1 water-to-gel ratio) are difficult to use. They are prone to excess bubbles, pre-mature jelling, film pits, low viscous flow, increased impurities and during processing sometimes pull up off the substrate if not annealed in a wet oven. Processing of these thick films is often done with room temperature baths, or slightly elavated temperatures, over several minutes in each bath. ==== Sensitizer ==== We use ammonium dichromate crystals or for redder reds Potassium dichromate but the most sensitive of the dichromates is Pyridine dichromate. We don't use it because of it's shorter life and difficult preparation. The addition of ammonium nitrate can make the dichromate several times more sensitive, but decreases the useful life and blue shifts the image. Approximate ammonium nitrate concentrations are usually in a ratio of 1 to 5 by weight to ammonium dichromate up to a maximum of 1 to 1. When the additional substance is washed out of the gelatin a net shrinkage occurs which amounts to a blue shift in reflection holograms and lays down Bragg planes in transmission holograms. ==== Filtering ==== At a minimum, filter the heated mixture through two coffee filters (Mr. Coffee) for a standard 8-30-350 film. For 6-30-200 and thicker emulsions, use one coffee filter. Run the filtered mix into the pouring container. When necessary, a finer grade lab filter may be used, we have forced warm gelatin through a 1 micron filter using a gear pump and also using a peristaltic pump. The use of a peristaltic pump makes metering and filtering possible at the same time. A simple syringe with a 2 micron filter is very effective and may double as a way to meter out a fixed amount onto a plate. ==== Applicator ==== The pouring container (with the film) is kept on an electric warming plate. The temperature of the plate should be carefully controlled to provide only enough warmth to prevent jelling (50-60 degrees C). We like to use a lab hot plate and water bath, the pouring container is a tea pot like bottle modified from a lab wash bottle. Any poly bottle that empties from the bottom will do. Some custom shaping of the "spout" may be necessary to prevent the formation of bubbles. === COATING TECHNIQUES === The coating station consists of a class 100 cleanhood or laminar flow bench, a dryer-heater unit and the turntable. The clean hood should be large enough to fit the turntable and two plate racks inside. (About 2 1/2' x 3 1/2' or larger.) A yellow safelight may also be mounted inside. Air flow should be 200 cfm or higher for this size hood. ==== Cleaning glass ==== There is a bit of an art to coating and it takes a little practice to become good at it. The first step is to prepare the plates by soaking over night in a soapy solution that contains some chlorine. The plates also need scrubbing and a rinse in deionized water. The final rinse should be done in or in front of the clean hood used for drying the plates. The chlorine soak has been found to aid in adhesion of the gel to the glass. The glass may be soda lime plate or float glass or any most any other kind but it has to be thick enough to withstand the shrinking forces generated during exposure. This means that it should be double strength or thicker(3 to 6 mm) for 8 x 10 shots, single strength (2 to 3 mm) for 4 x 5 and 5 x 7, and may be picture glass or as thin as 1 mm for 2 x 2 exposures. ==== Coating glass ==== The gelatin is poured over the dried plate in such a way that no gel spills off the edge and no bubbles are formed. This is accomplished by pouring a large puddle and gently rocking the tray till all edges are wet. The turntable is then turned on with the blower/heater for about 5 minutes. If the plate was uniformly wet and had no contaminants then the coating is likely to be uniform using these techniques. The range of RPM we found useful runs from 65 to 100, speeds outside this range failed to be uniform. Start with a rotation speed of about 80 RPM and position the heater-blower about 6 inches above and to one side of center of the coating tray. For 8 by 10 plates this offset is about 3 inches. The fine tuning of the position of the blower will greatly improve the uniformity of your coatings. ==== Ageing and thickness ==== The film is ready for exposure after it has been aged an hour or so for a 350 mixture or a day later for a 150 mixture. The addition of 1 or 2 ml of TMG will extend the useful room temp life of 350 film to a day or two and will make 150 film last for several weeks in a 21 degree C, 50% RH environment. The thicknesses of the commonly used mixtures after spinning at 80 RPM and after processing are as follows: 350 yields 5-6 microns, 250 yields 8-9 microns, 200 yields 10-12 microns, 150 yields 20-24 microns and 125 yields 25 to 50 microns depending on speed. ==== Bandwidths and color ==== The relative bandwidths run from 50 to 150 nm for 350 film, depending on processing used. 250 and 200 film make 10 to 50 nm bandwidths depending on processing and 150 film can get down to 8 nm but also runs as high as 30 nm. Very thick film can have bandwidths of less than 8 nm. The color of a film made from a 3-30-200 mixture is around 630 nm when shot at 514 nm. The color of 6- 30 film is around 590 for a 514 shot and a 10-30 mixture will easily be tuned to play back at the same wavelength it was shot at. Methods of planning and controlling color in display holograms are discussed below, similar but more precise methods are used for HOEs. === COLOR DICHROMATE OBJECT PREPARATION === The two color method produces rich red-orange and bright clean blue-green colors that mix to a creamy white. Color coding of the object is optional but helpful in most cases and production is done from two masters in two different films. The three color system requires color coding for red at the mastering stage but no coding for blue or green, which are mastered first. Both systems are part natural, part pseudo color and require only two laser lines and two film formulations. Blue is obtained naturally by using the 458 argon line and green or red are derived from the 514 line. In production the two color system is identical to current master/copy methods in that batches are shot at 458 or at 514 and later registered and laminated together. The three color system requires blue and green exposures in the same emulsion and red in a second batch. The laser must then be operated multiline or be switched constantly or a second laser introduced. The preferred method is multiline operation with independent shuttering except that max power in each line is reduced because several lines compete for available energy. The two color, two plate system makes very satisfying flesh tones and color balance is fairly easy to maintain because it can be done by mixing and matching batches and or individual holograms at the laminating stage. The two color single plate method has the obvious advantage of no registration problems but it has a limited color range because there are only 56 nm between 458 and 514nm. ==== Object preparation ==== Blue-green areas should be overcoated lightly with a bright blue pigment such as Liquitex Brilliant Blue #20002-381 or Pelikan Deep Blue #39. This will effectively inhibit refection at 514. The red-orange areas must be touched up with yellow pigment such as Liquitex #1002-411 or Pelikan Yellow #10 both of which absorb 458 but reflect 514. At this stage H1 masters or correctly colored copies can be made, the Blue-Green master may be made to reconstruct at 488 so that production copies can be done using only 488 and 514. The 514 exposure is done with the film side facing the reference beam and the 458 exposure is done the other way around with a spacer between the object and film having the same optical thickness as the 514 substrate. ==== Film preparations ==== A good blue or green production film can be made by mixing the 8-30-250 formulae with or without a ml of TMG. A good red or yellow film is made by reducing the amount of dichromate to 2 or 3 grams. The plates are ready to use after standing at room temp for an hour and they may be stored in a refrigerator for months on end. Better results may be obtained from some softer gelatins by ageing films for a few days. ==== Exposure procedures ==== Blue holograms may be made by exposing in a Denisyuk fashion @ 458, 441, 476 nm or some other line bluer than 488. The energy required is about 20 mj/cm*cm and it helps to do it with the reference at 50 degrees from the normal and with the E vector perpendicular to the plate to reduce noise from mirroring. Green holograms may be similarly produced by using the 514 line, again near Brewster's angle. This time it may pay to try 55 degrees because absorption is much lower @ 514 so "Newton's wood" type noise is more likely to show up.The energy required is about 90 mj/cm*cm. Red holograms result from using the red film formula and exposing @ 514 close to Brewster's angle. The fringe structure is expanded to red or yellow reconstruction because less material is washed out during development. If the master has been made in SHG using a HeNe then this copy will be a correct color reproduction. ==== Processing procedures ==== The film of gelatin is about 8 or 9 microns thick and requires much longer processing times than 4 or 5 micron broadband films. Development takes 3 to 5 minutes in kodak fixer, followed by a 1 minute rinse in tap water. Dehydration is done in warm isopropyl alcohol (48 to 55 degrees C) using at least 2 baths after the tuning bath and agitating mildly in each for about 30 seconds. Drying is most easily done by removing the plate very slowly from the last and driest bath. If it does not look uniform try soaking in warm water for 10 minutes and then dehydrate with more agitation. Fine tuning of the color may be done by soaking in the tuning bath. This is the way that we get the center reconstruction frequency to match the copy wavelength. Start with a master that is a little too red and gradually tune it to the correct color by repeated passes through the tuning bath and the last hot dry bath. 350, 250, and even 200 mixtures all respond to this method. A hydrometer is necessary to monitor the specific gravity of the tuning bath and maintain it at or near .86. Processing 350 film for masters is done this way but the same film can be processed for broadband reconstruction by using a shorter development time and skipping the tuning bath. Experimenting is the only way to get the desired results. Some guides to broadband techniques can be found in the proceedings of the first Lake Forest symposium in 1982. An alternative to multiple bath processing has been proposed by workers at IBM. They suggest that for thin films, on the order of our 350 or 400 mixtures, spinning the plate while spraying a series of fluids works best. Thin films are not easy to process in baths because of the fast diffusion of solvents in and out of the rather porous gelatin. In the IBM method, all of the regular baths are sprayed progressively for only a few seconds each onto the spinning plate. They felt that the spray system would be a superior way to automate processing techniques, we experimented with spraying many years ago but did not have the success that IBM has had. === Hazards === Dichromate powder is dangerous if inhaled and the liquid mixture may irritate some people if left on the skin. Dust masks and rubber gloves are therefore recommended whenever film is being made. Isopropyl alcohol has low toxicity but is quite flammable and must always be heated in a safe manner such as in a water bath. Alcohol fires may be extinguished with water, dry chemical, Halon or CO2. Glass must be handled carefully and whenever possible the edges should be ground before handling. === REFERENCES === These references are all by the same author and may be useful to the holographer that tries to apply the methods detailed in this paper. A design guide and brochure for HOE's is available on request. A video tape demonstrating this technology is also conditionally available from the author. *"Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)." S.P.I.E. Proceedings, Volume 212, pp. 22, 1979 *"Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College Holography Workshop and First International Symposium on Display Holography, July 1982. Lake Forest, IL. *"Practical Polymers for Holography", Second International Symposium on Display Holography, Lake Forest College, IL. *"Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug. 1987. *"Alternative Volume Recording Media, A Qualitative Comparison" Third International Symposium on Display Holography, Lake Forest College, IL 1988 *"Survey of properties of volume holographic materials", SPIE vol. 1051, Practicle Holography III, 1989 p. 68 - LA, CA. *"Novel Enhancement of Photopolymers", SPIE vol 1212, Practical Holography IV, 1990 LA, CA. '''''Last modified on 4/8/99''''' [[Category:Rallison]] a8e0ff6aeed14c1429133bd88a02e11e75bea1f4 0 203 1623 254 2013-05-12T04:07:56Z Jsfisher 1 1 revision wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- *'''Daguerreotype''' - first practical and commercial photographic process, introduced by Louis Daguerre in 1839. The sensitive material comprised silver iodide, deposited on a polished silver plated copper base. A positive image was produced by camera exposure and mercury "development", which turned light struck halides gray-white. The image was made permanent by immersing the plate in a solution of sodium chloride. *'''Daylight enlarger''' - early type of enlarger using light from a hole in a window to provide illumination of the negative. *'''Desensitizing''' - reducing an exposed emulsion's sensitivity to light. This can be done by the application of dyes or by using oxidation agents *'''Developer''' - chemical bath containing reducing agents, which converts exposed silver halides to black metallic silver, making the latent image visible. *'''Development''' - process of converting exposed silver halides to a visible image. *'''Diazo''' - abbreviation of diazonium compounds, which decompose under the action of intense blue or ultraviolet radiation, forming an image in an azo dye. *'''Dichroic filters''' - produced by metallic surface coatings on glass to form colors by interference of light. Used in high quality color enlarger heads. *'''Dichroic fog''' - purple-green bloom usually seen on negatives and caused by the formation of silver in the presence of an acid. *'''Dilution''' - reduction in the strength of a liquid by mixing it with an appropriate quantity of water. *'''Dimensional stability''' - substance's ability to remain unchanging in size when subjected to processing and drying. *'''Dish development''' - method of development used for processing single sheet, cut film or paper by immersing in a shallow dish of developer and agitating by rocking the dish. *'''Documentary photography''' - taking of photographs to provide a record of social and political situations with the aim of conveying information. *'''Dodging''' - control of exposure in photographic printing achieved by reducing exposure to specific areas of the paper. *'''Dry down''' - refers to the amount a print darkens after drying. *'''Dry mounting''' - method of attaching prints to mounting surfaces by heating shellac tissue between the mount and the print. *'''Dye destruction process''' - method of producing a colored image by partially bleaching fully formed dye layers incorporated in the sensitive material. *'''Dye-image monochrome films''' - black & white negative films designed for color processing. *'''Dye sensitizing''' - defined as all silver halides used in black & white emulsions are sensitive to blue light. Early photographic materials possessed only this sensitivity.''' *'''Dye transfer print''' - method of producing color prints via three color separation negatives. Negatives are used to make positive matrixes, which are dyed in subtractive primaries and printed in register. *'''Dynamism''' - picture structuring which relates to a sense of movement and action. 30e028a8809dbdd048e71dc51206b2594f192e7a 0 204 1625 256 2013-05-12T04:07:56Z Jsfisher 1 1 revision wikitext text/x-wiki [[Dichromated Gelatin Chemistry]] ff3322ac04e57c17933b0a410293ac9a872e4c31 0 817 1627 1626 2013-05-12T04:07:57Z Jsfisher 1 1 revision wikitext text/x-wiki == Introduction == Ralston introduced a notation for basic recipies for dichromated gelatin emulsions. He use a sequence of three numbers that indicated the quantities of dichromate, gelatin, and water, respectively, used in the formulation. For example, 5-30-200 in Ralson's scheme meant 5 grams of dichromate with 30 grams of gelatin and 200 grams (exactly equivalent to ml) of water made up the recipe. The normal for Ralston's notation was 30 grams of gelatin, while the dichromate and water ratios were allowed to vary. Many amateur holographers use common food-grade gelatin in their work. Knox Gelatin is the most typical. In the United States, Know Gelatin is available in convenient 1 oz. packets. An ounce is roughly 14 grams, so it can be convenient to express Ralston recipes using a 14 gram reference for gelatin instead of the more common 30 grams. &nbsp;Common Ralston recipes then become: {| width="200" |- | Ralston Recipe | Rescaled Recipe |- | 5-30-250 | 2.3-14.250 |- | 10-30-600 | 4.4-140200 |} 9bb2229edaa188026d0ea29ec668260ad1855f0d 0 818 1629 1628 2013-05-12T04:07:57Z Jsfisher 1 1 revision wikitext text/x-wiki === Early researchers (to 1974) === *T. A. Shankoff, "Phase holograms in dichromated gelatin" ''Appl. Opt.'' '''7:'''2101-2105, 1968 *T A Shankoff and R K Curran "Efficient, high resolution, phase gratings", ''App Physics Letters'' 13:pp239-241, 1968 *L.H. Lin, "Hologram Formation in Hardened Dichromated Gelatin Films." il ''Ap Optics'' 8:963-6 My, 1969 *H. Kogelnik, "Coupled wave theory for thick hologram gratings" ''Bell Syst Tech J.'' '''48''':2909-2947, 1969 *R.G. Brandes and others, "Preparation of Dichromated Gelatin Films for Holography." ''Ap Optics'' 8:2346-8 N, 1969 *R.K. Curran and T.A. Shankoff, "Mechanism of Hologram Formation in Dichromated Gelatin." ''Ap Optics'' 9:1651-7 Jl, 1970 *T.P. Sosnowski and H. Kogelnik, "Ultraviolet Hologram Recording in Dichromated Gelatin." ''Ap Optics'' 9:2186-7 S, 1970 *M. Chang and N. George, "Holographic Dielectric Grating; Theory and Practice" ''Ap Optics'' '''9''':713-719, March 1970 *L.H. Lin, "Method of Characterizing Hologram-Recording Materials." ''Opt Soc Am J.'' 61:203-8 F ,1971 *Milton Chang, "Dichromated Gelatin of improved optical quality", ''App Optics'', 10&nbsp;: p2550-2551, Nov 1971 *D. Meyerhofer, "Spatial Resolution of Relief Holograms in Dichromated Gelatin." ''App Optics'' 10:416-21 F, 1971 *Gary Fillmore, Richard Tynan, "Sensitometric characteristics of hardened dichromated gelatin films" ''J of Op Soc,'' 61:pp199-202, 1971 *K S Pennington, J S Harper, "New photo technology suitable for recording phase holograms and similar information in hardened gelatin", ''App Phys Lett'' 18: pp80-84, 1971 *W. S. Colburn, "Holographic Optical Elements", ''Technical Report, contract F33615-72-C-1156'', 1973 *F. T. S. Yu. "Effect of Emulsion Thickness Variations on Wavefront Reconstruction". ''App Optics'' '''10''':1324-1328 June 1971 *D. Meyerhofer, "Phase Holograms in Dichromated Gelatin.". ''RCA R.'' 33:110-030 Mr, 1972 *D. H. Close, A. Graube, "Materials for Holographic Optical Elements", ''Technical Report AFML-TR-73-267'', Oct. 1973. *A. Graube, "Holograms recorded with red light in Dye sensitized dichromated gelatin", Optics Comm.8:251-253 *D G McCauley, "Holographic Optical Element for visual display applications", App Optics, 12: 232-241, 1973 *D.H.Close, A. Graube, "Holographic Lens For Pilot's head up display", ''Techmical report, contract# N62269-73-C-0388'', 1974 *R D Rallison, "DCG applied with a record player and broadband processed in 2 minutes" ''Hughes Aircraft'', Jan 1974 (never published, just bragged a lot) === Additional selected DCG related publications (to 1996) === *S. K. Case. "Coupled Wave Theory for Multiple Exposed Thick Holographic Gratings". ''Opt Soc Am J.'' 65: 724-9 Je, 1975 *A.Alferness, S.K. Case, "Coupling in Doubly Exposed, Thick Holographic Gratings" ''Opt Soc Am J.''65:730-9 Je 1975 *R.V. Pole and H.P. Wollenmann, "Holographic Laser Beam Deflector". ''App Optics'' 14:976-80 Ap 1975 *S. K. Case, "Multiple exposure holography in Volume Materials", ''Doctoral Dissertation'', U of Michigan, 1976 *B.J. Chang, "Post Processing of Developed Dichromated Gelatin Holograms", ''Optics Communications'', '''17''' (3): 270-271, June 1976. *T. Kubota, T. Ose, M. Sasake and K. Honda "Hologram Formation with Red Light in Methylene Blue Sensitized Dichromated Gelatin" ''Applied Optics,'' '''15'''(2):556-558, Feb. 1976. *W. S. Colburn &amp; B. J. Chang "Holographic Combiner for Head-Up Displays", ''Technical Report AFAL-TR-77-110'' , Jan 1977 *H. M. Smith, ''Holographic Recording Materials,'' Springer Verlag, 1977 *A. Graube, "Dye Sensitized dichromated gelatin for holographic optical element fabrication" Photographic Sci and Eng, 22: pp37-41, 1978 *A. Graube, "Holographic optical element materials research", ''Technical report, Air Force contract # F44620-76-C-0064,'' 1978 *S.K. Case and W.J. Dallas, "Volume Holograms Constructed from Computer Generated Masks." ''App Opt'' 17:2537-40 Ag 15, 1978 *R D Rallison, "Fabrication of a holographic scanning disc" ''Technical report to IBM'', Raleigh NC, 1979 *R D Rallison, "Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)."''SPIE Proceedings'' 212:22, 1979 *B.J. Chang and C. D. Leonard, "Dichromated Gelatin for the Fabrication of Holographic Optical Elements", ''App Opt'' 18:2407-17 Jl 15, 1979 *S.P. McGrew, "Color Control in Dichromated Gelatin Reflection Holograms", ''Proc. SPIE'' '''215''':24-31, 1980. *B.J. Chang, " Dichromated Gelatin Holograms and Their Applications". ''Opt Eng'' 19:642-8 S/O, 1980 *W.R. Graver et al, "Phase Holograms Formed by Silver Halide Sensitized Gelatin Processing" ''App Opt'' 19:1529-36 My 1, 1980 *S.K. Case et al, "Multi facet Holographic Optical Elements for Wave Front Transformations". ''App Opt'' 20:2670-5 Ag 1 1981 *Sven Sjolinder, "Dichromated Gelatin and the Mechanism of hologram formation", ''Photo Sci and Eng'', 25: pp 112-117, 1981 *D. A.Winick, "Thick Phase Holograms", Environmental Research institute of Michigan, Level, January 1981 *L. Solymar &amp; D.J. Cooke , ''Volume Holography and Volume Gratings'', Academic Press, 1981. *J. Oliva et al, "Diffuse-Object Holograms in Dichromated Gelatin." ''App Opt'' 21:2891-3 Ag 15, 1982 *H. Bartelt, S.K. Case, "High-Efficiency Hybrid Computer-Generated Holograms." ''Appl Opt'' 21:2886-90 Ag 15,1982 *R D Rallison, "Hologram Scanner Design and Fabrication in Dichromated Gelatin (DCG)." Proc SPIE, August, 1982 *R D Rallison, "Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College *First International Symposium on Display Holography, July 1982 *L.D. Dickson, "Holography in the IBM 3687 Supermarket Scanner", ''IBM J. Res &amp; Devel'' 26:228-34 Mr 1982 *.J.E. Ludman, "Approximate Bandwidth and Diffraction Efficiency in Thick Holograms." ''Am J. Physis'' 50:244-6 Mr.1982 *Tung H. Jeong, ''Proceedings of the International Symposium on display holography,'' Vol I 1983 *Y.-Z Liang, "Multifocus Dichromated Gelatin Hololens". ''Appl Opt'' 22:3451-6 N 1 1983 *A. Fimia, "Noise Reduction in Holographic Images Reconstructed with Blue Light". ''Appl Opt'' 22:3318 N. 1, 1983 *J. Oliva et al, "Dichromated Gelatin Holograms Derived from Agfa 8E75 HD Plates" ''Appl Opt'' 23:196-7 Ja 15 1984 *R D Rallison, "Characteristics of Dichromated Gelatin (DCG) Scanners for Printing Applications"''Proc. SPIE''. 498: 199, 1984 *R D Rallison,"Applications of Holographic Optical Elements" Lasers and Applications,pp61-64 December 1984, *S. Calixto and R.A. Lessard, "Real-Time Holography with Undeveloped Dichromated Gelatin Films" ''Appl Opt'' 23:1989-94 Je 15, 1984 *Ryszard Gajewski "Holographic Technology for Solar Energy Concentration" ''Technical Report No. 87-1479'', 1984. *C. Solano, Lessard et al, "Red Sensitivity of Dichromated Gelatin Films".''Appl Opt'' 24:1189-92 Ap 15 1985 *J. C. Newell et al, "Holograms in Dichromated Gelatin: Real-Time Effects" ''Appl Opt'' 24:4460-6 D 15 1985 *Jose R. Margarinos &amp;Daniel J Coleman "Holographic Mirrors" ''Proc. SPIE'' '''523''':203-218, 1985. *C. Solano and R.A. Lessard, "Phase Gratings Formed by Induced Anisotropy in Dyed Gelatin Plates" ''Appl Opt'' 24:1776-9 Je 15 1985 *Richard D. Rallison, "Holographic Optical Elements (HOES) in Dichromated Gelatin (DCG)", ''Proc. SPIE'' '''523''':292-295 (1985). *S. Calixto et al "Real-Time Optical Image Processing and Polarization Holography with Dyed Gelatin". ''Appl Opt'' 24:2941-7 S 15 1985 *Tung H. Jeong, P''roceedings of the International Symposium on display holography'' Vol II 1986 *T. Kubota, "Recording of High Quality Color Holograms" ''Appl Opt'' 25:4141-5 N 15 1986 *P. Hariharan, "Silver Halide Sensitized Gelatin Holograms: Mechanism of Hologram Formation." ''Appl Opt'' 25:2040-2 Jl 1, 1986 *R. Changkakoti and S.V. Pappu, "Study on the pH Dependence of Diffraction Efficiency of Phase Holograms in Dye Sensitized Dichromated Gelatin." ''Appl Opt'' 25:798-801 Mr 1 1986 *C. Solano et al Methylene Blue Sensitized Gelatin as a Photosensitive Medium for Conventional and Polarizing Holography" ''Appl Opt'' 26:1989-97 My 15 1987 *Daniel K. Angell, "Improved diffraction efficiency of silver halide (sensitized) gelatin", ''Appl Opt'', 26:4692-4701,1987 *R D Rallison,"Holographic Scanners for Machine Vision, Printing, and Bar Code Applications." Proc. SPIE 747:pp 1987 *H K Liu, "Simplified dichromated gelatin hologram recording process", ''App Optics'', 26:372-376, 1987 *D.J. Jacobs and M. G. Marsland, "Reduction of Sensitizer Concentration Gradients in Dichromated Gelatin Films" ''J Phys E''. 20:899-901 Jl 1987 *R. D. Rallison, "Materials for Volume Phase Holographic Notch Filters" ''SBIR #A 86-68 Final Report'', U.S. Army CECOM, Ft. Monmouth, N.J. Aug.1987 *Jon D. Masso "Multilayer Thin Film Simulation of Volume Holograms" ''Proc. SPIE'' '''883''':68-72, 1988 *R D Rallison, "Cascaded Transmission Holograms for Head-Up Displays". ''Proc. SPIE'' 883: pp 1988 *N. Capolla and R.A. Lessard, "Processing of Holograms Recorded in Methylene Blue Sensitized Gelatin" ''Appl Opt'' 27:3008-12 Jl 15, 1988 *R. D. Rallison "Incoherent Multifocus Hololens design and fabrication", ''Proc. SPIE'' '''1183''':663-668 1989 *R. D. Rallison "Survey of properties of volume holographic materials", ''Proc. SPIE'' '''1051''':68-75 1989 *James M Tedesco, "Holographic laser -protective filters and eye-wear" Opt Eng 28:p609-615, 1989 *Y. Amitai et al "Holographic Elements with High Efficiency and Low Aberrations for Helmet Displays", ''Appl Opt'' '''28''':3405-3416 Aug 15 1989 *J. L. Salter and M. F. Loeffler, "Comparison of dichromated gelatin and Dupont HRF-700 photopolymer as media for holographic notch filters" ''Proc. SPIE'' '''1555''':268-278 (July 1991) *Chris Rich, David Cook, "Lippman volume holographic filters for Rayleigh Line rejection in Raman Spectroscopy", Proc. SPIE 1461:2-7, 1991 *R. D. Rallison, "Control of DCG and non silver holographic materials" ''Proc. SPIE'' '''1600''': 26-37 1991. *R D Rallison,"Polarization properties of gelatin holograms" ''Proc''''. SPIE'' 1667:pp 1992. *R D Rallison, "Using Thick DCG, 30 to 100 microns" Proc. SPIE 1914:pp 1993. *L D Dickson, R D Rallison et al, "Holographic polarization-separation elements" ''Appl Opt''. 33:5378-5385, 1994 *R. D. Rallison and S. R. Schicker, "Wavelength compensation by time reverse ray tracing", ''Proc. SPIE'' '''2404''': 217-225 1995 *Hans Dieter Tholl, "Polarization properties of volume phase gratings", ''Optical Engineering'', '''34'''(10)2879-2885 Oct 1995 *Hans I Bjelkhagen, ''Holographic Recording Materials'', SPIE publications, 1996. *R D Rallison, Steve Arnold, "Wavelength compensation at 1.064 microns using hybrid optics" Proc SPIE 2689, 1996 [[Category:Rallison]] [[Category:DCG]] 45265f7eb8e91d55d9b9ef3aadcc5f8e57b14744 0 205 1631 258 2013-05-12T04:07:57Z Jsfisher 1 1 revision wikitext text/x-wiki For an overview see [[The Mechanics of Gelatin and the DCG Process]].. ===Dark Reaction=== '''Can you elaborate on dark reaction?''' '''Jeff Blyth responds:''' A good question ! ----- It needs a chemist to do it justice because it is complicated. Although it straightforwardly means dichromate reacts slowly with gelatin at room temperatures without light being involved, it does need some explaining. If you are not interested in the finer chemistry detail then stop reading here . Most oxidizing agents such as oxygen in the air, nitrates (saltpeter as in gunpowder etc) , and chlorates can be mixed with combustible materials and just sit there inactive virtually forever unless something such as a lighted match gives them that vital spark which triggers the chain reaction and rapid burn up. So these oxidants need what’s called “activation energy” as a kick start. However in the case of dichromates the chromium is a member of what are known in the Periodic Table as “transition metals” . These are inclined to have the peculiar ability to indulge in low activity with little activation energy which is why they are used universally as catalysts for low temperature reactions. They have variable valency which is why we have referred in this forum to CrVI going to Cr V going to CrIII The transition metal iron in our blood is doing this sort of low temperature oxidation work for us of course too. The transition metal effect is to do with atomic orbitals where the electrons have a large array of complicated empty orbitals to whizz about in some of the time and to get through barriers without having to be kicked to jump over the normal activation energy barrier that non- transition metal ions have to do. A non- transition metal such as say Aluminum which is always Al III in our water based alum chemistry here and cannot be reduced or oxidized to a different valency but it does make complexes with the gelatin and hardens it (but not quite as strongly as CrIII). So back to dichromate which has 6 electrons missing from its uncombined metallic state. The electrons have been taken mainly by 3 oxygen atoms in a not very strong arrangement and these electrons are actively whizzing around the Cr atom’s empty orbitals as well as their main base around the oxygen atoms. Energy is gained for the system if 3 of them can return permanently to the Cr atom by being instrumental in getting the oxygens to swap them for other electrons in neighboring organic groups in the gelatin to give more stable arrangements producing partially oxidized gelatin. So the dark reaction of dichromate is primarily a matter of oxidation of the gelatin without a kick start with light energy or extra heat and it can be slowed down in a ‘fridge but needs to be in a freezer to really slow it down. Incidentally the less pure the dichromate the more it contains other transition metals such as copper and the more it enables this catalysed oxidizing effect to occur in the dark. More acidity also increases it which is why the more acidic ammonium salt in unexposed gelatin film gives it a shorter shelf life than the potassium salt. ===Gelatin and Anti-Crystallization Properties=== Let’s remember that yet one more of the great features of gelatin is its ability to hold quite concentrated solutions of salts within itself as a form of gelled solid solution. This is a great feature for us holographers because without it some of our valuable techniques would be spoiled by the normal crystallization processes which would transform glass clear film into the equivalent of frosted window glass. This special anti-crystallization feature can be undermined if we allow concentrated salt solutions to crystallize on the surface of the gelatin because it can then encourage crystal seeding to occur within the gelatin. So if one is making a “G307” system where the coated gelatin is dipped into a bath of say 6% potassium dichromate one needs to gently wipe off the excess droplets of dichromate salt off the surface before drying . (This system needs high dichromate salt concentrations for exposure to 532nm but NOT if one is exposing with blue wavelengths.) This also applies to the diffusion system for making silver halide gelatin film, where careful removal of silver nitrate solution in surface droplets is needed before drying and immersing in the bromide bath. Another (but less common ) way that anti -crystallization property can me reduced is by excessive drying by overheating so that the inherently bound in water found in normal gelatin film is driven off or the salt-laden gelatin is stored under very low humidity. Jeff ===Converting Dichromate to Chromate=== I hope I can just clarify something about potassium dichromate versus chromate. You can readily convert dichromates into chromates by adding the right amount of alkali to a stirred solution of say 5% potassium dichromate until it gets to a pH of about 8 to 9. The chemistry really is straightforward enough. I will just run through it for future reference. Potassium chromate is the potassium salt of Chromic Acid : H2CrO4 where the 2 acid H's are substituted for 2 K's Now to see how potassium Dichromate (K2Cr2O7) is made up, please just note down the total formula from adding one potassium chromate (K2CrO4) to one chromic acid (H2CrO4). You then get a total of K2H2Cr2O8 . now just take away 1 H2O and you get K2Cr2O7. So dichromates are all just 1:1 combinations of chromate salts with chromic acid. There is of course no need to use potassium hydroxide to do the conversion, Na OH will work just fine. I have just calculated that 100 ml of 5% K2Cr2O7 will require 1.36 g solid sodium hydroxide to convert it all to the chromate form. (The colour of the solution changes from the intense orange yellow to a light canary yellow when the conversion is complete.) Some of you will have already spotted that 5% K2Cr2O7 solution has got more chromium compound in it than the intended 5% K2 Cr O4 solution. To make it equivalent you need to cut down the volume of solution used by a third. But I don’t think this is a critical issue . Jeff 6a8c4153a84a1246ba37681491a3ca1582622227 0 206 1633 260 2013-05-12T04:07:57Z Jsfisher 1 1 revision wikitext text/x-wiki == Here are variables and their effect on the DCG process == '''AmDi concentration''' - Lower redder less sensitive, higher bluer more sensitive '''Drying Temperature (Low ~20C)''' - Lower yields more triple helices, thus harder gelatin, clearer and more narrow band '''Drying Temperature (High ~30C)''' - Higher yields less triple helices, thus softer gelatin, less clear and more broadband '''Emulsion thickness''' - Thicker more narrow banded less light gets through, thinner more broadband '''Emulsion temp while mixing''' - Too low deforms on emulsion, too high pits, optimal centered at 120F '''Film freshness (film age)''' - Young broadband with milky tendeny, old narrow band and clear tendency '''Room Temp (exposure)''' - Warmer increased sensitivity '''Room Humidity (exposure)''' - More humid increased sensitivity '''Exposure Time''' - Longer harder bluer narrower banded, shorter softer redder broader banded '''Dark reaction time''' - Longer harder bluer narrower banded, shorter softer redder broader banded '''Fixer Time''' - Too short milky soft , too long harder bluer '''Light or heat fixing (if applicable)''' - Low light/heat softer broader banded milky, lots light harder bluer narrow band '''H2O rinse time''' - Too short non clear film '''H2O rinse temperature''' - Hotter broadband, lower narrow band '''IPA concentrations (ratios''') - Faster increase in ratios (35, 100) broadband, slow increase (30, 50, 70, 90, 100) narrower banded, modifying 50% from 35- 50% shifts color towards blue. '''IPA time''' - Shorter broadband, longer narrow band '''IPA temperature''' - Higher broadband, lower narrowband '''Blow drying''' - Too slow uneven blotches, to short degradation of holo over time '''Wavelength''' - The shorter wavlengths the higher sensitive, and will greatly effect the other variables 119bc19e660927aae15b70893617f3f082a94778 0 819 1635 1634 2013-05-12T04:07:57Z Jsfisher 1 1 revision wikitext text/x-wiki == Weird DCG Recipes == 3.6-30-467, Chromium Acetate, Ethanol Markova, Nazarova, and Sharlandjlev, “Control of the Spectral Position of DCG Reflection Holograms,” Institute of Optical Materials and Technology. *64.3 g gelatin, Bloom strength of 210 *7.71 g ammonium dichromate *0.64 g chromium acetate *65 ml C2H5OH (ethanol) *Distilled water to make 1000 ml Plates are coated with the solution at 50°C by doctor-blade method to 20 µm. 5-30-200, Ammonium Nitrate Bahuguna, Beaulieu, and Arteaga, “Reflection display holograms on dichromated gelatin,” Applied Optics, volume 31, issue 29 (1992). *2.5 g of ammonium dichromate *1.5 g of ammonium nitrate *100 cc of distilled water *Heated to 70°C *15 gm of USP grade Baker's gelatin (125 bloom strength) powder slowly added while stirring Spin-coat at 100 rpm the still ~70°C emulsion for 90 seconds under hot-air gun. Dry vertically in a dark box. Plates are ready after about 6 hours. Sensitivity was reported as 100 mJ/cm2 at 488 nm. [In Rallison’s Thick DCG paper, he associated ammonium nitrate with hardening.] 4.5-30-500, Ammonia Coblijn, Alexander B., "Theoretical background and practical processing techniques for art and technical work in dichromated gelatin holography", SPIE Institute Series Vol. IS 8 (1990). *100g water *6g gelatin *0.9g ammonium dichromate *2ml ammonia 35% (added last) Household ammonia is typically 5-10%. [Presumably, the ammonia inhibits the dark reaction.] DCG Notes The basic formula for dichromated gelatin is water plus gelatin plus either ammonium or potassium dichromate. The amounts of each ingredient influence the characteristics of the result. Exposure energy requirements, color shift, emulsion thickness, etc., are all impacted by the formulation. It is convenient, then, to have a standard for formula reference. Richard Rallison promoted using a system of three numbers to describe a formula—grams of dichromate, grams of gelatin, and grams (milliliters) of water. For example, 8-30-250 would be the notation for a recipe consisting of 8 grams ammonium or potassium dichromate, 30 grams of gelatin, and 250 grams of water. To make comparisons among formulae, the gelatin number is always 30 in Rallison’s notation. The three numbers can be scaled equally up or down for producing different quantities of emulsion. (Personally, I usually scale the numbers to 7.1 grams of gelatin, 7.1 grams being the mass of gelatin in quarter-ounce packet of Knox brand gelatin.) Thickness and Bandwidth The ratio of gelatin to water affects the viscosity of the emulsion, and that in turn affects the typical thickness of emulsion on the glass plate. The thickness influences the bandwidth of the final hologram. Rallison reported the following results for emulsions applied by 80 RPM spin coating method: Formula Thickness Bandwidth xx-30-350 5 – 6 µm 50 – 150 nm xx-30-250 8 –9 µm 10 – 50 nm xx-30-200 10 – 12 µm 10 – 50 nm xx-30-150 20 – 24 µm ~8 nm Replay Color Shift The ratio of dichromate to gelatin influences the color shift. The following table has typical values for exposures taken at 514 nm: Formula Color Shift 3-30-xxx 630 nm 6-30-xxx 590 nm 10-30-xxx ~514 nm Exposure Sensitivity My personal guess at typical exposure requirements for the basic recipe 8-30-300 emulsions. Wavelength Exposure 405 nm 5 mJ/cm2 442 nm 15 mJ/cm2 475 nm 40 mJ/cm2 488 nm 60 mJ/cm2 514 nm 125 mJ/cm2 532 nm 200 mJ/cm2 A great many factors may have a dramatic effect on sensitivity, notably humidity and temperature, so the above table is only a point of reference. Sensitivity also varies inversely with the dichromate concentration—halving the amount of dichromate would double the exposure requirement, for example. <br> General Notes “Control of DCG and non-sliver holographic materials”, SPIE volume 1600, International Symposium on Display Holography, 1991. Using 8-30-350 emulsion, exposed at 75% RH and 80 F. Wavelength Sensitivity 441 nm &lt;1 mJ/cm^2 488 nm 4 mJ/cm^2 514 nm 50 mJ/cm^2 532 nm 100 mJ/cm^2 7.6. Sensitizer- We normally use ammonium dichromate crystals or for redder reds Potassium dichromate but the most sensitive of the dichromates (up to three times) is Pyridine dichromate. We don't use it because of its shorter life and difficult preparation. The addition of ammonium nitrate can make the dichromate several times more sensitive, but decreases the useful life and blue shifts the image. Approximate ammonium nitrate concentrations are usually in a ratio of 1 to 5 by weight to ammonium dichromate up to a maximum of 1 to 1 . When the additional substance is washed out of the gelatin a net shrinkage occurs which amounts to a blue shift in reflection holograms and lays down Bragg planes in transmission holograms. <br> by Joe Farina&nbsp;» Wed Aug 08, 2007 11:53 am There is also a paper in SPIE Institute Series Vol. IS 8 (1990) called "Theoretical background and practical processing techniques for art and technical work in dichromated gelatin holography" by Alexander B. Coblijn. This is an unusual but interesting paper based on practical experience. It is kind of an "independent viewpoint" of DCG based on holographic testing, and is not just an empty rehash of things previously published. Anyway, he used the following DCG formula: • 100g water • 6g gelatin • 0.9g ammonium dichromate • 2ml ammonia 35% (added last) I'm not sure what the concentration of ordinary household ammonia is, but that's what the above sounds like. I didn't notice a specific explanation regarding the inclusion of the ammonia, presumably it lowers the pH and increases sensitivity as Jeff explained. Formula Characteristics xx-30-350 Thickness after spinning at 80RPM: 5-6um. Bandwidth: 50-150nm. xx-30-250 Thickness after spinning at 80RPM: 8-9um. Bandwidth: 10-50nm. xx-30-200 Thickness after spinning at 80RPM: 10-12um. Bandwidth: 10-50nm. xx-30-150 Thickness after spinning at 80RPM: 20-24um. Bandwidth: ~8nm. 3-30-xxx Replay: 630nm from 514nm exposure. 6-30-xxx Replay: 590nm from 514nm exposure. 10-30-xxx Replay: ~514nm from 514nm exposure. Holography: A Practical Approach. Ackermann and Eichler. Page 193. Plates prepared from 7% gelatin built up on a spin table to 10-20um then dried are then sensitized in a 5% ammonium dichromate solution for 5 minutes. Wavelength Sensitivity 442 nm 10 mJ/cm^2 475 nm 80 mJ/cm^2 488 nm 100 mJ/cm^2 514 nm 250 mJ/cm^2 My personal guess at typical exposure requirements for typical 8-30-300 emulsions. Wavelength Sensitivity 405 nm 5 mJ/cm^2 442 nm 15 mJ/cm^2 475 nm 40 mJ/cm^2 488 nm 125 mJ/cm^2 514 nm 200 mJ/cm^2 DCG formulae Red-- mix 3-30-250 using Potassium Dichromate spin on at 80-90 RPM, expose single beam 90-100 mj\cmE2 @ 514 if RH = 60% and T = 70 F. Process: develop 5 min., rinse, 30 sec in 1HAB @ 120 F and .86 SG. Dry with slow pull from LHAB followed by hot air. Color should be bright Red-Orange. Rallison’s recipe for red(-der) holograms: 200:30:3. Less AmDi = redder result. Less light = redder result. IPA:water ratio of first bath and bath duration. Longer = greater shift. Richard D. Rallison, Ralcon Development Lab 1.3 Serendipity Back to the story, I returned to Hughes with one of Mike's broken 8 x10 inch dichromates determined to produce my own, Mike was not about to share more of his tricks of the trade so I was on my own. I coated Knox unflavored gelatin "Jello" on glass plates in my apartment using a record player built into an old steamer trunk. The dichromate processes described in the literature by Shankoff, Lin and Chang were all too time consuming to suit me. Mike had suggested during a phone conversation that I mix in all the sensitizing dichromate before coating to save some time and that helped. Everything I made initially came out milky white until I accidentally dropped an exposed plate into Milton's hardening fixer prior to soaking it in water. It was only in the fixer for 30 seconds but that proved to be sufficient to harden it enough to take the shock of hot alcohol without precipitation. A short process was immediately at hand. From then on I could make coatings on any glass surface in 5 minutes, expose them in another 5 minutes, process them in another 5 minutes and seal them up in less than 5 minutes. I immediately produced a few boxes full for show and tell and then lit the lab on fire. I managed to keep that trick under my hat until 1982, when Fred Unterseher persuaded me to publish it. I inadvertently also sold it to Steve McGrew (Holosonics) in 1979 and thought he might make it public just as I was selling it to IBM, but he never did publish. What he did publish was a very fine paper on color control in DCG in 1980, one of the first papers useful to artists working in color at the time. My method of controlling the color and clarity of master holograms was not disclosed til 1985. I dropped a developed broadband hologram into a certain bath that was about 75% alcohol and when I retrieved it and dipped it in hot dry alcohol it came back as a low scatter blue hologram. From that day in Nov 1975 I had a fast, tunable way to make bright masters that added almost no noise to the copies and so I finally had all the processes I needed to start making masters and churning out thousands of bright "dichromates" for sale. Which is what I did. 1b1f81ae7df9d524ff5b86ef48e5502a8f4cb629 0 207 1637 262 2013-05-12T04:07:58Z Jsfisher 1 1 revision wikitext text/x-wiki Jeff Blyth has online instructions for making Silver Halide Plates. *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] ===Gelatin Film thickness=== In the case of MBDCG a thinner film can give a bit more sensitivity because you can have more MB dye in. If x % of dye is optimum for a dried film of 10 microns then for a dried film of say 40 microns you need to cut it down to 0.25x% and that is usually bad for sensitivity. If you leave it at x% then you kill too much object beam light. However you can get away with x% if you are able to do split beam reflection work (unlikely you have enough laser power with MBDCG unless you are making say 1 sq cm size images). Single beam transmission H’s could be OK though. ===Silver Halide=== If the diffusion method is tried on coatings much thicker than 7 microns it is troublesome. I have tried it on ~ 100 micron gelatin and decided that it was not viable. The problem being that the rate of diffusion decreases exponentially with time and AgNO3 can carry on diffusing into the thick film and away from the incoming bromide ions . If you leave it long enough (several minutes) for the bromide ions to catch up and combine with the furthest Ag ions near the glass then the front end may have already been in the Br bath too long and you start to get grain growth . If you don’t catch those unreacted Ag ions at the glass end then they quite rapidly develop up in the (ascorbic acid pH 6) sensitizer bath causing bad darkening or bad fog. You can stop this by giving the film a very prolonged soak in tap water (with its Cl- ions) after the Br bath before the sensitizer bath. What you get is then virtually all the silver bromide in the first few microns and none in the gelatin nearer to the glass , you might just as well have coated it thinner in the first place. However using the conventional process with AgBr precipitated in molten gelatin solution you still get fundamental problems if you try to coat ultra thick layers. The processing chemicals take much longer to migrate in and grain growth and unevenness is inevitable. I needed to make some experimental coatings about 1 mm thick and although I got gratings they were sadly dim. I struggled to get any grating at all. Once upon a time, Agfa produced an experimental 8E75’B’ coating that was twice as thick as usual but still only ~ 15 microns . Nobody found they could get a good result from it compared to their standard 7 micron. Jeff ===Hans' Diffusion Post=== As promised, here is a revision of Jeff Blyth's diffusion method that will allow you to make very bright holograms, and some theory as to why I think it works so well. When making your own holographic plates there are two requirements for bright results that work against one another: Lots of AgBr should be in the emulsion, and the AgBr crystals (grains) that are made up from all this AgBr should be as small as possible. It normally is very difficult to make an emulsion that complies to both these requirements and lots of articles have been written up about solving this problem. Lots of methods have been invented, but few are as reliable as Jeff's diffusion method. Why is it so difficult to make small grains: Imagine you have a gelatin solution into which you want to introduce AgBr grains. The traditional method would be to add to this gelatin solution a solution of AgNO3 and a solution of KBr. Both would be added at the same time at a certain rate. This method is called the double jet method. When the addition of the two solutions is started, at first nothing happens. Only the concentrations of both solutions slowly increase in the gelatin solution. Above a certain concentration, suddenly lots of Ag+ ions combine with lots of Br- ions to form very minute AgBr crystals. The formation of these crystals causes a fast decrease in concentration of both the AgNO3 and the KBr. As soon as the concentration drops below a certain value, any added AgNO3 + KBr will not create new grains (as we would like), but cause the grains that are already there to grow. This growing of the grains is not desirable. So, what I mean to say is that for new grains to form, the concentrations of the AgNO3 + KBr need to be above a certain critical value. Concentrations below this value cause grain growth and even lower concentrations do nothing at all. As you can see now the double jet method needs precisely controlled flows of liquids to allow for concentrations to be above this critical nucleation concentration to allow as many micrograins to form. Second problem is that if there are many small grains present, any newly added AgNO3+KBr prefers to settle onto those grains rather than forming new nuclei. And here lies the difficulty in making emulsions with both small grains and lots of grains at the same time. Most of the old recipes for making Lippmann emulsions are for making very fine grain emulsions, but with a very low amount of silver in them. Manufacturers of holographic film usually keep their methods for making their emulsions a secret just because of this reason. Now if there were a method of instant mixing a gelatin emulsion of very high concentration AgNO3 with a liquid of very high concentration of KBr (and very quickly after mixing both the excess AgNO3 and KBr could be removed), very small grains in high quantity would be virtually guaranteed. And this is where Jeff's brilliant diffusion strategy comes to the rescue: Imagine you had a very thin gelatin layer that was soaked with AgNO3 and this would be suddenly dunked into a solution of KBr, the KBr would be introduced to the AgNO3 throughout the surface of the gelatin as it diffuses into the layer. So a great many small grains of AgBr would form instantly everywhere inside the very thin layer of gelatin. If the layer is then quickly washed after this step, all excess AgNO3 and KBr are removed and thus further growing of the grains is no longer possible. This is not the whole story by a long shot though. In normal kitchen gelatin there are often left-over chemicals from the fabrication process that actually encourage grain growth. Any chlorides present in the gelatin would hamper the formation of small grains because AgCl is a lot more soluble than AgBr and also because when the AgNO3 is added to the gelatin, the first nuclei that are formed are AgCl nuclei and that's not what we want because we want the sudden process of virgin AgBr nucleation as the gelatin is dunked into the KBr solution. Any chemicals with Sulfides in them also cause grain growth. Luckily there is a way to clean your gelatin. More about this later. Just like there are chemicals that encourage grain growth, there are also chemicals that discourage grain growth. And that is where the second brilliant idea of Jeff comes to play. It just so happens that the dye used in the diffusion process (pinacyanol chloride) is one of those chemicals that help prevent grain growth. Adding this dye (that makes your emulsion sensitive to red laser light) to the KBr solution will help keep the grains small: as the gelatin is dunked into the KBr, the newly formed grains are quickly coated with dye molecules, preventing further settling of new AgBr onto them. One problem with the dye is that it does not like to be in water. That is why the KBr mixture is actually a mixture of water+methanol. The dye is very soluble of methanol and will stay even in solution if some water is present. Ok, so much for theory. Here is the procedure. Rather than writing up the differences from Jeff's original procedure I will now proceed and type the whole recipe. ====Washing the gelatin==== For this you need a small glass jar. Fill jar with 20ml of de-ionized (DI) water and add about 2.2 gram of gelatin. Next slowly warm this mixture to about 45C until the gelatin is completely dissolved. Take a plastic tupperware and pour this liquid into it and allow it to gel. When the solution has gelled, cut this gel up into small cubes with a plastic knife. Pour about 100ml of cold DI water into the tupperware tray, rock it a little and let it sit for about 30 minutes. (this step allows any contaminants in the gelatin to diffuse into the DI water). Pour off the DI water and add fresh DI water, rock and let it stand 30 minutes again. Repeat this procedure about 4 times. When you're done washing the gelatin, put it back into the glass jar and put it in the fridge (not the freezer) for later use. ====Preparing the glass==== When put into a alkaline developer, gelatin does not want to stick to glass anymore. So the glass needs to be prepared for holographic use. Firstly wash a piece of glass (say 20x30cm) with vinegar (this will remove some of the grease that is on the glass). After that, vigorously rub the glass with household ammonia and be very careful not to get any of this into your eye because it will make you blind forever. Now the glass will be very clean. The next step will be to chemically treat the glass to make it sticky. ====Making the glass sticky for gelatin==== Add about 0.5ml of 3-amino-propyltriethoxysilane (less is better than more) to 100ml of Acetone and rub this solution onto your cleaned glass plate. Let the plate sit for about one hour and then clean it again. This time with a Ammonia based glass cleaner. Your glass has now been coated with a very thin layer of molecules that on one side stick to the glass. The exposed sides of these silane molecules have -NH3+ endings that bond well with the gelatin. ====RainX==== You will need a second glass plate to be able to make a nice gelatin coating. Throughly clean a glass plate of the same size as the plate that was prepared from step [2] and rub it with an automotive anti rain agent such as Rain-X. And then rub it with a clean dry towel. On two opposing edges of this plate stick a long piece of Scotch tape. (During the coating step, gelatin will be poured onto this plate and the silane treated plate will be put on top of this gelatin puddle. The Scotch tape acts as a spacer and allows a perfect gelatin coating with just the right thickness when dried.) ====Preparing the chemicals==== * Mix 1g of pinacyanol chloride in 1000ml of methanol. This solution will last you a life time. * Mix 33ml of water with 66ml of Methanol. To this solution add 6 gram of LiBr and 2.5ml of the dye solution. Pour this liquid into a Tupperware tray that is big enough to hold your glass plate and close it. ====Wear Safety Glasses==== If you get AgNO3 in your eye you will be blind forever.:Take your washed gelatin from the fridge and warm it up to 45C again. When it has become completely liquid again, add 1.2 gram of AgNO3 to this solution. Often the solution becomes milky when you do this, but if you stir for about a minute, it will become transparent again. ====Coating the Plate==== Heat your Silane treated glass plate with a hair drier and while holding it level (USE KITCHEN GLOVES), pour a puddle of your gelatin on top of it. Quickly place the Rain-X treated glass plate on top of it and allow the gelatin to completely spread between the glass plates. After a few minutes the gelatin will gel and both plates will stick together. Now place this sandwich into the fridge and leave it there for a few hours. ====Washing Baths==== When doing the diffusion method it is important to stop the grain growth as soon as the grains are formed. Also it is preferable to remove any excess silver nitrate from the coating as soon as possible. So, prepare two trays of DI water to remove most of the AgNO3 and LiBr that is left over in the gelatin and one tray with tap water (most tap water contains some chloride that will precipitate with whatever Ag+ ions that are left after washing). To the tap water bath you should add a few drops of liquid dishwasher fluid. ====Diffusion Step==== After a few hours remove your glass sandwich from the fridge into your safe lighted room. With a plastic knife remove the Rain-X treated plate from your Silane treated plate. If all went well, the gelatin coating should stick to the Silane treated plate in a perfect smooth coating. Without waiting for the plate to dry or become warm, immediately drop this plate into the LiBr bath and leave it there for about 45 seconds. Then quickly take the plate out and transfer it to the first DI water bath for about 1 minute. Then the second DI water bath, then the tap water bath. Let the plate drip dry by setting it almost vertically against an object on your table. After about 15 minutes when most of the water has dripped from the plate you can use a cool hair drier to finish drying. ====Sensitizing==== Your freshly made plate will not be sensitive enough yet for practical use. Also the gamma of the emulsion will not be suitable yet for holography. Prepare a solution of 100ml water + 1.2 grams of Ascorbic Acid (=vitamin C) + 0.4 gram of NaCO3 + few drops of dishwasher liquid. Immerse your plate into this for about 2 minutes and dry again. When the plate is dry, it is ready for use and to be exposed for the brightest Denisyuk hologram you have ever made. Ok, so that's about it. It looks like a complicated and long procedure. But after you have done it a few times, you will find it easy and simple to do and reasonably fast. It is possible to make a number of plates in one day and store them in the fridge for later use. This procedure addresses a number of problems in the original procedure: * Lots more silver will be present in the gelatin. This will make your holograms a lot brighter. The original recipe calls for first coating the gelatin and afterwards introducing the AgNO3. This can certainly be done, but the gelatin needs to be very very hard and squeegeed well after adding the AgNO3. Otherwise AgNO3 will crystallize on the surface of the gelatin layer and prevent diffusion from taking place. * This method will allow for very soft gelatin layers to be made. This is interesting if you want to experiment in doing SHSG. * In the original method there is also some Ascorbic Acid in the LiBr+dye bath. This certainly does work, but you run the risk of developing out any AgNO3 that has not precipitated out. This causes some darkening of the plate. It is better to do the sensitizing afterwards. ====A SHORTCUT THAT IS ADVISABLE FOR FIRST TESTS==== * This adjustment will allow you to do the diffusion method very fast and still give the same brightness. * Skip steps [1] through [7] * Immerse a PFG-01 plate in a solution of 20% Sodium Thiosulfate (non hardening fixer) until it has become completely transparent. And rinse in DI water and dry. * Prepare a solution of 1 ml DI water + 0.18g AgNO3. * With a laser printer transparency spread a few drops of this solution over the surface of the fixed out plate and squeegie the plate very well. * Start from step 8 in the above procedure. * You have now upgraded your PFG-01 plate to a plate that competes well with the brightest plates in the world. I have done the original method, my adjusted method and the quicker method many times over and they give predictable results but have now switched to a completely different method (using double jet) that I don't want to write about just yet. ====INTERESTING EXPERIMENTS TO TRY==== *Gelatin at low concentration is much easier to coat than the 10% that is required for the above procedure. It would be interesting to try to make your fresh dry gelatin into a very fine powder in a kitchen slurpy mixer. Then load this fine powder in a very cold solution of AgNO3. The solution needs to be cold because otherwise the powder will become a sticky mass. Next run this mix through a coffee filter to drain off excess water+AgNO3. Then pour your LiBr+dye mixture over the powder that is still in the coffee filter (do catch what drips out of the filter because it can be used again). Next pour large amounts of DI water through the filter. If all liquids are rather cold during this procedure the gelatin will not clump up and it just might work. After this procedure you would have holographic gelatin that can dissolved when needed at concentrations of about 2% and coated by just pouring on a horizontal glass plate. I don't know if this procedure would work. But if it does work it would be very nice. I tried it once but made a mistake in the dark and made a mess of it. So I was not able to conclude if it is possible or not. *To coat a layer of 2% gelatin on glass to which some dichromate is added. Then make this layer really hard in an oven and use the shortcut method I wrote about above. The layer should be very smooth and hard enough to allow a good squeegee. I have not tried this, but if it works it will be a lot faster. Well, that's about all I know about the diffusion method. I very much enjoyed using it. Please understand that this is by no means the only way to do the diffusion method. If you want to have a go at it, try it this way first and then experiment with your own idea's. I am sure you will come up with idea's that will improve upon this method. 5fbf90e6847cc2d93b5cf5d99a86c8cdc0a705d4 0 209 1639 266 2013-05-12T04:07:58Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:DBattin.jpg]] [http://www.geocities.com/greenpagoda/islandholo1.html Dave's Web Site] IT all started for me in the Museum of Holography, in the late 70s. after making one visit i was hooked for life! Seeing what could be done was unbeleivable..... I then joined as a member and started to read any information i could absorb. Attending college in Boston I found all kinds of new info at the college libaries. Upon graduation from college I headded west, finding work near Los Angles in a large machine shop, I found this very convenient for making tooling for my holographic components. After leaving LA and returning to New York, I continued my holographic studies, and met a fellow holographer, Mark Segal (owner of now defunct Spatial Images International)at this lab we produced a large ammout of DCG holography. A short time later a head hunter contacted me about a job working for company called Farirchild Weston Space and Camera, the job was for an optical engineer, I couldn't wait for the interview! They hired me in a flash! The optics lab was about 2500 sq.ft of total OPTICS! Lenses, mirrors, lasers a gigantic isolation table (20 tons+), I spent the next five years building telephoto lenses ths size of 55 gallon drums and tiny ccd cameras that would fit in matchbox! This is where I really learned about the nature of light and optics. 79317af696e9bf934471b16ba84e245512b76295 0 210 1641 268 2013-05-12T04:07:58Z Jsfisher 1 1 revision wikitext text/x-wiki I have successfully killed bad fogging on Slavich plates (without also killing the photosensitivity) by soaking them for exactly 60 seconds in a solution of; 20g Ferric EDTA and 10 g KBr per litre. (This solution keeps for years.) (Ferric EDTA is ethylenediaminetetraacetic acid ferric sodium salt) What amazed me was that the photosensitivity of the plates did not drop noticeably afterwards without my needing to resensitise them in say 2% ascorbic acid (vitamin C) at pH ~6. ~Jeff Blythe 4ecc0fdfdaf5ca0d4a5e4728a284842d6cb89678 0 211 1643 270 2013-05-12T04:07:59Z Jsfisher 1 1 revision wikitext text/x-wiki from [http://Nobelprize.org www.nobelprize.org] Dennis Gabor – Autobiography [[Image:Gabor.gif]] I was born in Budapest, Hungary, on June 5, 1900, the oldest son of Bertalan Gabor, director of a mining company, and his wife Adrienne. My life-long love of physics started suddenly at the age of 15. I could not wait until I got to the university, I learned the calculus and worked through the textbook of Chwolson, the largest at that time, in the next two years. I remember how fascinated I was by Abbe's theory of the microscope and by Gabriel Lippmann's method of colour photography, which played such a great part in my work, 30 years later. Also, with my late brother George, we built up a little laboratory in our home, where we could repeat most experiments which were modern at that time, such as wireless X-rays and radioactivity. Yet, when I reached university age, I opted for engineering instead of physics. Physics was not yet a profession in Hungary, with a total of half-a-dozen university chairs - and who could have been presumptious enough to aspire to one of these? So I acquired my degrees, (Diploma at the Technische Hochschule Berlin, 1924, Dr-Ing. in 1927), in electrical engineering, though I sneaked over from the TH as often as possible to the University of Berlin, were physics at that time was at its apogee, with Einstein, Planck, Nernst and v. Laue. Though electrical engineering remained my profession, my work was almost always in applied physics. My doctorate work was the development of one of the first high speed cathode ray oscillographs and in the course of this I made the first iron-shrouded magnetic electron lens. In 1927 I joined the Siemens & Halske AG where I made my first of my successful inventions; the high pressure quartz mercury lamp with superheated vapour and the molybdenum tape seal, since used in millions of streeet lamps. This was also my first exercise in serendipity, (the art of looking for something and finding something else), because I was not after a mercury lamp but after a cadmium lamp, and that was not a success. In 1933, when Hitler came to power, I left Germany and after a short period in Hungary went to England. At that time, in 1934, England was still in the depths of the depression, and jobs for foreigners were very difficult. I obtained employment with the British Thomson-Houston Co., Rugby, on an inventor's agreement. The invention was a gas discharge tube with a positive characteristic, which could be operated on the mains. Unfortunately, most of its light emission was in the short ultraviolet, so that it failed to give good efficiency with the available fluorescent powders, but at least it gave me a foothold in the BTH Research Laboratory, where I remained until the end of 1948. The years after the war were the most fruitful. I wrote, among many others, my first papers on communication theory, I developed a system of stereoscopic cinematography, and in the last year, 1948 I carried out the basic experiments in holography, at that time called "wavefront reconstruction". This again was an exercise in serendipity. The original objective was an improved electron microscope, capable of resolving atomic lattices and seeing single atoms. Three year's work, 1950-53, carried out in collaboration with the AEI Research Laboratory in Aldermaston, led to some respectable results, but still far from the goal. We had started 20 years too early. Only in recent years have certain auxiliary techniques developed to the point when electron holography could become a success. On the other hand, optical holography has become a world success after the invention and introduction of the laser, and acoustical holography has now also made a promising start. On January 1, 1949 I joined the Imperial College of Science & Technology in London, first as a Reader in Electronics, later as Professor of Applied Electron Physics, until my retirement in 1967. This was a happy time. With my young doctorands as collaborators I attacked many problems, almost always difficult ones. The first was the elucidation of Langmuirs Paradox, the inexplicably intense apparent electron interaction, in low pressure mercury arcs. The explanation was that the electrons exchanged energy not with one another, by collisions, but by interaction with an oscillating boundary layer at the wall of the discharge vessel. We made also a Wilson cloud chamber, in which the velocity of particles became measurable by impressing on them a high frequency, critical field, which produced time marks on the paths, at the points of maximum ionisation. Other developments were: a holographic microscope, a new electron-velocity spectroscope an analogue computer which was a universal, non-linear "learning" predictor, recognizer and simulator of time series, a flat thin colour television tube, and a new type of thermionic converter. Theoretical work included communication theory, plasma theory, magnetron theory and I spent several years on a scheme of fusion, in which a critical high temperature plasma would have been established by a 1000 ampere space charge-compensated ion beam, fast enough to run over the many unstable modes which arise during its formation. Fortunately the theory showed that at least one unstable mode always remained, so that no money had to be spent on its development. After my retirement in 1967 I remained connected with the Imperial College as a Senior Research Fellow and I became Staff Scientist of CBS Laboratories, Stamford, Conn. where I have collaborated with the President, my life-long friend, Dr. Peter C. Goldmark in many new schemes of communication and display. This kept me happily occupied as an inventor, but meanwhile, ever since 1958, I have spent much time on a new interest; the future of our industrial civilisation. I became more and more convinced that a serious mismatch has developed between technology and our social institutions, and that inventive minds ought to consider social inventions as their first priority. This conviction has found expression in three books, Inventing the Future, 1963, Innovations, 1970, and The Mature Society, 1972. Though I still have much unfinished technological work on my hands, I consider this as my first priority in my remaining years. Honours Fellow of the Royal Society, 1956. Hon. Member of the Hungarian Academy of Sciences, 1964. D.Sc. Univ. of London, 1964, Hon. D.Sc. Univ. of Southampton, 1970, and Technological University Delft, 1971. Thomas Young Medal of Physical Society London, 1967. Cristoforo Colombo Prize of Int. Inst. Communications, Genoa, 1967. Albert Michelson Medal of The Franklin Institute, Philadelphia, 1968. Rumford Medal of the Royal Society, 1968. Medal of Honor of the Institution of Electrical and Electronic Engineers,1970. Prix Holweck of the French Physical Society, 1971. Commander of the Order of the British Empire, 1970. Married since 1936 to Marjorie Louise, daughter of Joseph Kennard Butler and Louise Butler of Rugby. From Les Prix Nobel en 1971, Editor Wilhelm Odelberg, [Nobel Foundation], Stockholm, 1972 This autobiography/biography was written at the time of the award and later published in the book series Les Prix Nobel/Nobel Lectures. The information is sometimes updated with an addendum submitted by the Laureate. To cite this document, always state the source as shown above. Dennis Gabor died on February 8, 1979. da0bbce15e2113daaa6ef128352e50f0980f1522 0 820 1645 1644 2013-05-12T04:08:00Z Jsfisher 1 1 revision wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. The are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. Epoxy is normal sealant. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. [[Category:DCG]] [[Category:Beginner]] 4792233bfbc9b98a576a2a36e5f14facb53c28f1 0 212 1647 272 2013-05-12T04:08:00Z Jsfisher 1 1 revision wikitext text/x-wiki Dichromated Gelatin (DCG) is one of the brightest media for recording holograms. It is used in art as well as [[HOE]] fabrication. [[A Beginners Approach to DCG]] by John Pecora [[A Simple DCG Recipe]] [[G307 DCG Formula]] Increased overall sensitivity and to 514nm - 532nm [[MBDCG]] [[DCG Theory]] [[Sealing DCG Holograms]] [[The Mechanics of Gelatin and the DCG Process]] [[DCG Variables]] [[Coating Methods]] [[Troubleshooting DCG]] 151638f01f328b547127e6f3311d0750a3661be9 0 213 1649 274 2013-05-12T04:08:00Z Jsfisher 1 1 revision wikitext text/x-wiki (For details and setup examples, see the [[Holography_Technology]] page.) (For a more technical description see [[Holograms]].) ===Comparison=== ===Single Beam Reflection=== Also called a Denisyuk Hologram this is the most common first hologram. It is fairly easy to set up and can be viewed in white light. This type of hologram is one of the least expensive as there are minimal optics and the stability requirement can be minimized by touching the plate to the object. ===Single Beam Transmission=== This is actually easier than a Single Beam Reflection however since it requires a laser for viewing it is not as common. The depth of field shown is often much better. This type of hologram is one of the least expensive as there are minimal optics and the stability requirements can be minimized. ===Split Beam Reflection=== This hologram is also known as an off-axis reflection hologram, or a "straight reflection" hologram. The laser beam is split into two beams with an partially mirrored beamsplitter, which can be mounted on a variable slide. One portion of the divided beam is spread with lenses or diffusion glass to illuminate the object, set in front of the holographic recording medium. The other portion of the laser is spread through a lens array or spacial filter, then reflected off of a collimating mirror, which is directed at the back of the hologram-to-be at the reference angle. The reference angle is determined by: practicality in the optical set-up; Bragg's angle and the frequency of the recording laser; and the angle of the intended viewing light; with a range of 38 to 46 degrees giving good interference fringes. The reference angle will become the illumination angle of view for the finished hologram. Steering mirrors are needed to complete this set-up. This type of hologram can be more expensive to produce as there are additional optics needed and more stringent stability requirements. It can be much brighter than a Single Beam Reflection. It can also contain relatively vast parallax. Depth is limited as in a Denisyuk hologram. (Image plane reflection holograms offer greater depth and projection possibilities, but their parallax potential is not as great as in a straight reflection hologram) ===Split Beam Transmission=== This is the most common way to make a transmission hologram. It requires a beamsplitter and is most often used to make an H1 for copying. This type of hologram is going to be more expensive as there are additional optics needed and more stringent stability requirements. ===H1 to H2 Copies=== This is making a copy of a hologram. It is a more complicated set up requiring a beamsplitter and a good Master Hologram (H1). It allows the hologram to bisect the film plane with some of the scene in front of the plate and some behind. ===Rainbow Transmission=== This is a special case of an H2 copy. It is a transmission hologram made by masking the master hologram (H1) to a horizonantal slit. It is viewable in white light but the color changes with viewing position. ===Multiplex=== This is a very complicated set-up and has to do with storing many close views or perspectives of an object onto a single holographic plate in the form of slits. Then those slits are imaged to the same relative location in space creating a focused, multi perspective image. A hologram is then made of the combined image projections creating 3 Dimension hologram. ===Holographic Optical Element (HOE)=== [[HOE]]s are holograms that work like optical elements (mirrors and lenses). ===Computer Generated=== By computing the interference patterns, it's possible to simulate a hologram in software. The result when printed to a transparency using a standard printer is usually low resolution and inefficient, but can work. [http://www.medcosm.com/prog_CGHmaker.htm MedCosm CGH Software (free)] 72613e8c79569859dab05e20926dd67cf1212570 0 214 1651 276 2013-05-12T04:08:00Z Jsfisher 1 1 revision wikitext text/x-wiki Diffusers can be used to soften the shadows from the object beam for softer lighting effects. From a artistic lighting standpoint, a laser is considered a point source. To make softer lighting we need to widen the beam source. There are many ways to do this: *Broken Light Bulbs *Sandblasted Glass *Etched Glass *Glass or Plastic sanded in one direction only Commercial diffusers are also available. You can specify how much diffusion you need. A 10% diffuser allows most of the light to pass through. A 30% diffuser spreads more of the light. It should be remembered the diffusers also randomize the polarization. This can increase the fog level of the hologram. It is very important the the diffuser be shielded from the plate so no stray light can hit the plate directly. ae42fed899c7a48d9ebc34c466c95c78475e8965 0 821 1653 1652 2013-05-12T04:08:00Z Jsfisher 1 1 revision wikitext text/x-wiki '''Diffusion method - estimated cost'''<br>November 18 2002 at 6:53 AM As promise, I post my estimated costs table for a batch of 20 holoplates made with the Jeff Blyth's diffusion method. Silane, LiBr, Pinacyanol come from Sigma-Aldrich. All prices are in November 2002 Euros (1 Euro ~ 0,97 USD) {| style="wikitable" border="1" |- | Chemical | Price/Quantity | Diluted quantity | Quant/20 plates | Price/20 plates |- | AgNO3 (6%) | 18,11/10g. | 166 ml | 60 | 6,55 |- | LiBr (3%) | 11,2/100g. | 3300 ml | 300(*) | 1,02 |- | Pinacyanol (0,1%) | 16,81/250mg | 250 ml | 7,5 | 0,5 |- | Ascobic Acid (1%) | 2,11/30g | 3000 ml | 300(*) | 0,21 |- | Gelatin (15%) | 9/1000g | 6666 ml | 100 | 0,14 |- | Chrome Alum (2%) | 3/100g. | 5000 ml | 300(*) | 0,18 |- | Silane (1%) | 31,16/100ml | 10000 ml | 100 | 0,31 |- | Glass (4x5) | 12,5/20 | - | 20 | 12,50 |- | Total for 20 plates | - | - | - | 21,41 or 1,07/plate |} (*) I assume I change for each batch * LiBr + Dye bath * Chrome Alum hardener * Ascorbic Acid sensitizer But please pay attention of this following note from Jeff about the LiBr bath: "Please note that I myself reuse the dye/LiBr baths several times. A little bit of precipitate in the bottom of container (it is only AgBr) can be left there and the liquid poured off or the solution just filtered. So you can make many plates if you want to for the initial expence. The quantity of subbed plates you could make is enough for an industrial production run!" I don't calculate price for water, acetone and methanol because those products are cheap. First batch can seems expensive because you need to purchase relatively big quantity in regard of the used quantity and you need to some laboratory material. Hope this can give you the curiosity to test this easy method. Jean PS: my 2nd batch has failed because I don't care to dry plates enough after Chrome Alum bath! Results was presence of chrome salt who fog the plates. I'll try hardening gelatin with a bath of 1% formalin in DI water. f40d5afa50dcb94445ae52d04dcd760813bd3ae4 0 822 1655 1654 2013-05-12T04:08:00Z Jsfisher 1 1 revision wikitext text/x-wiki <br> [[http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-21-4-4044 Speckle-free, shaded 3D images produced by computer-generated holography]] <br> 5f2ca782670e7ea128e5eff6e00ef136bfed8da1 0 215 1657 278 2013-05-12T04:08:00Z Jsfisher 1 1 revision wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 823 1659 1658 2013-05-12T04:08:01Z Jsfisher 1 1 revision wikitext text/x-wiki Much of the energy projected onto a diffuse surface is scattered at high angles as it is either reflected or transmitted. A volume type diffuser also depolarizes light as it is scattered. The gain of a projection screen is the ratio of energy reflected into a specific angular zone to the energy that would be reflected from a perfect diffuser. Small glass beads on a screen will return projected light to its source, yielding a high gain in an angular zone around the source. Other shapes of refracting and reflecting material can be molded into screens to produce high gains in retroreflecting geometries and a few anamorphic or single plane scattering surfaces that may be made of lenticular optics. The available directions for high gain and the angular shape of the gain zone are limited by refractive optics but become nearly arbitrary for diffractive optics. Dispersion in diffractive optics prevent them from being used over very broad bandwidths but if the application is insensitive to this dispersion then diffuse energy may be directed and concentrated in some very unusual ways using diffractive screens. The simplest form of directional diffuser is made by interfering a plane or diverging wave with a diffuse wave in either a reflection or transmission format. The resulting hologram will reconstruct the diffuse source when illuminated at the original angle and wavelength. If the same hologram is used as a projection screen, the information being projected onto it will only be visible when the diffuse source is visible. All other viewing positions and illumination geometries will see a diminished projection or nothing at all. The position and size of the original diffuse source will determine the viewing zone and the gain of the screen. A small diffuse source recorded a meter away from the holographic plate will form a very high gain screen that is visible only when the viewer is in the angular zone subtended by the small source at 1 meter. The same screen may be made to reflect only a narrow band of wavelengths centered around a particular phosphor or laser line, making it practically invisible for all other directions and colors. This sort of screen can be useful in conserving projected CRT or laser light in a cockpit or simulator. The angles chosen for construction and reconstruction are somewhat arbitrary so that specular reflection from the projector can be avoided in the viewing zone. We have constructed green screens of this variety with gains of 25 and efficiencies greater than 70%. When photons are precious and a small viewing zone or box is acceptable then this is a very good solution. The viewing zone cannot always be constructed with real sized sources at end use distances. The viewing zone can always be specified as a set of angles or a specific pattern and scaled with lenses during construction. Perhaps the most useful and general method of creating a specified viewing zone is to project the pattern to infinity during construction. This is done by placing a correctly scaled diffuse pattern 1 focal length away from a lens placed close to the recording plane. The scaling is most easily done by ray tracing from the film plane through the lens to a plane one focal length away. This method also cancels aberrations introduced by the lens during construction. The lens limits the size of the hologram and thus the size of the screen that can be recorded this way. Practical lenses for this purpose are usually only 6 or 8 inches in diameter although some are available up to about 20 inches. Large screens must then be made some other way. One of the applications we have dealt with recently required that we make a screen several times larger than we were able to expose in one shot. The angular viewing window was large and the surface area of the final screen was also large. We were limited by available laser light and lenses to a screen about 5 inches square. In order to make a larger seamless screen we multiplexed many overlapping exposures of the small screen on a much larger glass plate. One screen consisted of 144 separate exposures. The reason we could do this and maintain a constant angular viewing zone is because we had recorded a diffuse surface from infinity. In use the screen is visible only when the surface is reconstructed at infinity behind the viewer. Since it is at infinity, the angular zone remains constant for any size extended surface. This trick would be incredibly difficult to duplicate with conventional optical elements. Another important property of these screens is their nearly transparent appearance to anyone not in the viewing zone. These screens may be applied to windows in observation and control towers where they remain transparent while reflecting just like an opaque beaded reflecting screen for those in the viewing zone. Simple small LCD projectors can easily be seen in a lighted room due to the high gain and efficiency of the screen and the view of the outside world is only slightly colored and obstructed. Backlit displays or control panels may also be overlaid with this type of screen to project information as needed without obscuring the backlit displays. This property is even more difficult to duplicate in refractive optics. Any refractive or reflective surface that diffuses incident radiation at one angle usually does so at all angles. Diffractive optics on the other hand do very little to incident radiation at the wrong angle or the wrong wavelength. We refer to the second type of screen as an infinite conjugate directional diffuser because of its unique scaling property. Other directional diffusers have an ideal viewing zone that includes a finite distance and cannot be extended in size without enlarging and moving the viewing zone. Either variety may be constructed as a transmission or reflection hologram but all of our work has been with reflecting structures which are also naturally wavelength selective. Transmission screens can be used as diffuse illuminators of objects or selected areas of a plane. Patterns with unique properties in scale, focus and intensity distributions may be produced with these methods. Holographic directional diffusers are a unique class of optical elements that in general cannot be duplicated with conventional optical components. <br> '''''<br> Last modified on 8/2/97''''' [[Category:Rallison]] 27c780e3bf65ca08d82ad754a10023dd9186c2df 0 216 1661 280 2013-05-12T04:08:01Z Jsfisher 1 1 revision wikitext text/x-wiki Here is a [http://rudieberkhout.home.mindspring.com/SPIE-Acompactdisplay.htm Great Article] by [[Rudie Berkhout]]. 2dc1ff8bef87677ee63899438d74c914cfdfcd7e 0 217 1663 282 2013-05-12T04:08:01Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.vilamedia.com/ VilaMedia's Web Site] 6d589f6d169cc09c6f5b9b6de0975f261ebfecb1 0 218 1665 284 2013-05-12T04:08:01Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.integraf.com Integraf] Dr. Tung H. Jeong (better known as "T.J.") is a professor emeritus at Lake Forest College, Lake Forest, Illinois, and has over 35 years of experience in holography. He has led the field of holography as researcher, innovator, consultant, and, most significantly, educator. Having authored numerous articles, T.J. is recognized as a leading scholar in holography. TJ's recent publications include an article published in Applied Optics, the most widely read international holography journal. Besides research, T.J. has also produced two motion pictures. One entitled, "Introduction to Holography," was sponsored and marketed by Encyclopedia Britannica. A teacher at heart, T.J. has been invited to lecture and teach seminars at over 500 universities, professional societies, and industrial sites in Europe, China, Russia, among other international locations. T.J. has also co-chaired international conferences on holography and optics in Russia, Bulgaria, and Hungary. Moreover, for nearly 30 consecutive years, T.J. has hosted holography workshops for novices and experts. In 1982, T.J. started the triennial International Symposium on Display Holography. His most recent symposium attracted over 120 scientists, artists, and businessmen from 18 countries. Together with Dr. Hans Bjelkhagen, a visiting scientist from Sweden, T.J. discovered technology that makes true-color holograms possible. T.J. is also credited with the discovery of cylindrical holograms, changing holograms from flat formats into images people could walk around and view from all perspectives. In 1973, T.J. shared in the development of the technology that created three-dimensional moving holograms and was the first to implement the use of optic fibers, making holograms simpler and less costly to make. In the business world, T.J. serves as a worldwide consultant to corporations in various industries to develop holographic solutions. For example, T.J. has worked extensively with DuPont on their development of holographic photopolymers. With the development of this technology, holograms is becoming a common part of people's lives. (Photo: Encyclopaedia Britannica Educational Corp., 1972) T.J. joined the faculty of Lake Forest College in 1963 and served as director of the Center for Photonics Studies. He came to the U.S. from China as a young boy in 1948. Upon graduation from Amarillo High School in Texas, he attended Yale University under a full-scholarship, and received his B.S. degree in physics and mathematics in 1957. He completed his Ph.D. degree in nuclear physics at the University of Minnesota in 1963. A member of many professional societies, T.J. is a Fellow of the Optical Society of America and the recipient of the Robert Millikan Medal from the American Association of Physics Teachers. He is also recipient, of the Saxby Medal of the Royal Photographic Society of Great Britain and the Lifetime Achievement Award from the International Holographic Manufacturer's Association. T.J. has regularly chaired of the annual conference Practical Holography - Materials and Applications, sponsored by the International Society of Optical Engineering (SPIE) and the Society for Imaging Science and Technology (IS&T), taking place in San Jose, California. In November 2005, T.J. was a keynote speaker at the Holopack Holoprint international conference in Shenzhen, China. 97b7ea478b7f0878f6b1fdfbcc8be43f4ea6a0b0 0 219 1667 286 2013-05-12T04:08:01Z Jsfisher 1 1 revision wikitext text/x-wiki ==Drilling a hole in a drill press== *Layout the position of a hole with a scribe. *Mark the exact hole position with a punch. *Drill large holes by predrilling a hole matching the diameter of the web of the drill bit. *Choose the correct speed for the size hole and the material being drilled. *When in doubt use slow speeds and strong feeds. *Smaller holes require quicker speeds and lighter feeds. *Back holes in soft materials with another piece of material to prevent "Blowout". ==Seting up a drill press== *There shold be only the smallest amount of play when trying to move the chuck back and forth by hand. *Make sure when drilling through work that the drill bit can not come in contact with the table. *Use a piece of 1/2" drill rod in the chuck with a square to measure the table for squareness. *Setup holes so the minimum amount of quill extention is required for drilling a hole. ==Speeds and Feeds== *Steel *Aluminium *Soft Wood *Hard Wood ==Safety== *Never leave the key in the chuck wihile changing drill bits. *Never wear gloves while holding work in a drill press. *Always try to hold down work by bolting it to the table or by using a vise. *Always usy eye protection when using a drill press. *Unplug or remove the dafety key when chaning drill bits. *Never allow the chip fromed by drilling a hole to grow larger than 1 inch. If the chip starts to become a string relax pressure on the feed until the chip breaks off. 8942021b2424387fca466042bac1ea6493cbe919 0 222 1669 292 2013-05-12T04:08:01Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Edwesley.jpg]] Ed Wesly Ruby Pulsed Hologram - Fermilab PROFESSIONAL OBJECTIVE: To continue to share my wealth of knowledge and experience with more students in the fields of lasers, optics, holography and photography. TEACHING EXPERIENCE: Full-Time Faculty, Harrington College of Design, teaching Physics of Light (Optics), Photo-History, and College Math in the Digital Photography Department, January 2005 to present. Adjunct Assistant Professor, teaching a variety of classes in the Art and Technology and Liberal Arts Departments at the School of the Art Institute of Chicago, including the Beginning and Intermediate/Advanced Holography Studio, Optics for Artists, 3-D Hard Copy, and The Physics of Everyday Objects, January 1986 to present, with a couple of hiatuses. Instructor, Columbia College, Chicago, for the courses, "The Physics of Lasers, Holograms, and Modern Optics", "Photographic Theory/Laboratory Practice for Cinematographers", and "Imaging Optics", February 1985 to June 1997. Teacher, Cicero School, Cicero, IL, 7th and 8th grade Math Classes, September 1981 to June 1982. Director of Education for the Fine Arts Research and Holographic Center, Chicago, IL, June 1980 to May 1981. Teacher, Hardey Preparatory School, Chicago, 6th, 7th, and 8th grade Math Classes, September 1977 to June 1980. TECHNICAL EXPERIENCE: Production Holographer, CFC International, Countryside, IL, laboratory technician preparing holographic images for mass production, October 1998 to November 2004. Sales Engineer, BEA electro-optics, Des Plaines, IL, manufacturer's representative for a variety of electro-optical companies, June 1997 to October 1998. Research Associate at Lake Forest College, Lake Forest, IL, supported by a grant from a manufacturer of medical equipment to test the feasibility of replacing conventional optics in some of their equipment with Holographic Optical Elements, October 1987 to February 1993. Holographic Engineer for Northwestern University, Evanston, IL, researching holographic endoscopes using Ruby laser light piped through fiber optics, May 1986 to May 1987. Holographic Engineer for Holicon Corporation, Evanston, IL, setting up a studio to record holographic portraits using a Ruby laser, May 1986 to May 1987. Holographer for the 15 foot Bubble Chamber at Fermilab, Batavia, IL. Part of a team using a Ruby laser to make holograms of atomic particle tracks, March 1985 to April 1986. Optical Engineer for Magnaflux Corporation, Chicago, IL. Designed and built an 8 by 8 foot isolation table equipped with an Argon laser for real time interferometry of large objects, October 1983 to September 1984. EDUCATIONAL BACKGROUND: University of Illinois at Urbana, Bachelor's of Science Degree in the Teaching of Mathematics, January 1976. PROFESSIONAL ORGANIZATIONS: Member of the Optical Society of America, (OSA), and the Society of Photo-Instrumentation Engineers (SPIE). Councillor for Chicago Chapter of SPIE/Optical Society of Chicago Featured Speaker at the June, 1997 meeting of the Optical Society of Chicago. PUBLICATIONS TEXTBOOKS (self-published): INSTRUCTION MANUAL FOR THE HOLOGRAPHY STUDIO AT SAIC, September 1995 OPTICS FOR ARTISTS, September 1995 (e-version on-line Fall 2003) PHOTOGRAPHIC THEORY/LABORATORY PRACTICE For Cinematographers, September 1995 IMAGING OPTICS, February 1996 VIDEOS: "Ruby Laser Guts", 1996, and "Gaseous Lasers", 1996 SELECTED ARTICLES: "Inside-Out Engineering: Characterizing the Holographic Stereogram Printer at The School of the Art Institute of Chicago", Proceedings of the SPIE, 1997. "A Toast to Nick Phillips", Leonardo, Volume X, Number 3, 1992. "A Proposal for a National Space Monument", Proceedings of the SPIE, Vol. 1600, 1991. "Holography of Particle Tracks in the Fermilab 15-Foot Bubble Chamber," with W. Smart et al., Nuclear Instruments and Methods in Physics Research A297, 1990, p.364-389. "Teaching Holography in an Art School Environment," Proceedings of the SPIE, Vol. 1396, 1990. "Progress in True Color Holography", with T. Jeong, Proceedings of the SPIE, Vol. 1211, 1990. "Recycling Holographic Plates", Proceedings of the Third International Symposium on Display Holography, Lake Forest College, 1988. "Exploring Personal Holography", Darkroom and Creative Camera Techniques, Nov/Dec. 1986. "Seven Single Beam Projects", Proceedings of the Second International Symposium on Display Holography, Lake Forest College, 1985. Technical Editor for holosphere, the Advocate of Holographic Art, Science, and Technology, 1985 to 1991. REFERENCES: Dr. Tung Jeong, emeritus, Lake Forest College, Lake Forest, IL (Tjeong@aol.com) Dr. Hans Bjelkhagen, DeMontfort University, Leicester, England (Hansholo@aol.com) Dr. Manfred Stelter, PTI, Oak Creek, WI (pti@execpc.com) Dr. Gerald Cohn, Cyber-Tech, Evanston, IL (cybertek@megsinet.net) Dr. Elizabeth Wright, School of the Art Institute of Chicago, Chicago, IL (ewright@artic.edu) Dr. Pan Papacosta, Columbia College, Chicago, IL EXHIBITIONS: GROUP SHOWS Untitled, Richard Hunt Art Center, Benton Harbor Michigan, November 1996. Candy for the Eyes, Mind and Sol Gallery, Chicago, IL, September 1995. Unknown Chicago, Gallery 312, Chicago, IL, July 1995. The Fourth International Exhibition of Display Holography, Lake Forest College, July 1991. Matter Over Mind Sculpture Conference, Fermilab, Batavia, IL, May 1991. Diorama Wonderama, Gallery 836, Chicago, IL, November 1990. L.A.S.E.R. Members Show, Holos Gallery, San Francisco, CA, Summer 1990. New Media, New Directions, Northern Indiana Arts Association, Munster, IN, August, 1990. International Congress on Art in Holography, May - July 1990. The One-Liner Show, Gallery F-XU, Chicago, IL, February 1990. Visual Perceptions: Color, Light and Space, Gallery of Design of the Merchandise Mart, Chicago, IL, February 1989. The Third International Exhibition of Display Holography, Lake Forest College, July 1988. Visions in Light, Museum of Holography, Summer 1988. Images in Time and Space, Montreal, Canada, May 1987 to June 1989. The Holographic Instant: Pulse Laser Holograms, at the Museum of Holography, New York, May to October 1987. A.I.R. Waves at the Museum of Holography, New York, January to May 1987. 2 X 2 Show at the School of the Art Institute of Chicago, May 1986. Holography Group Show at the Limelight, Chicago, February 1986. Holography Exhibition at the School of the Art Institute of Chicago, November 1985. The Second International Exhibition of Display Holography, Lake Forest College, July 1985. New Light, Chicago Public Library Cultural Center, July 1984. The Connie Show, W.P.A. Gallery, Chicago, IL, April 1984. Stare Magazine Fifth Anniversary Show, at Word City, Chicago, June 1982. Post-Mortem Moderne, at the House o' Beauty, Chicago, IL, July 1980. First Contact, Chicago, IL, February, 1979. Illinois Photographers' Lottery, De Kalb, IL, May, 1978. EXHIBITIONS: ONE MAN SHOWS Down in the Basement, Artigliography, Indianapolis, IN, September - October, 1990. Doodles, Atlanta Gallery of Holography, Atlanta, GA, April 1990 Recent Pulsed Stuff and Other Delights at Benny's CASINO, Chicago IL, August 1986. AWARDS: Artist in Residence Direct Grant, from the Museum of Holography, New York, October 1984. Participant in the International Congress on Art in Holography, St. Mary's College, South Bend, IN, July 1990. COLLECTIONS: Global Images, Vancouver, British Columbia, Canada. Museum of Holography Collection, MIT Museum, Cambridge, MS. Dimensional Imaging Consultants, Niles, MI. Hans Bjelkhagen, Leicester, England 0c1e24f97d4b1a7f71c759f8f0b647ef523acaf8 0 224 1671 296 2013-05-12T04:08:02Z Jsfisher 1 1 revision wikitext text/x-wiki Emmett Leith (born in Detroit, Michigan, died December 23, 2005) was a professor of electrical engineering at the University of Michigan and the inventor of three-dimensional holography. Leith was educated at Wayne State University. Professor Leith and his coworker Juris Upatnieks displayed the world's first three-dimensional hologram at a conference of the Optical Society of America in 1964. In 1979, President Jimmy Carter awarded Leith with the National Medal of Science for his research. [http://en.wikipedia.org/wiki/Emmett_Leith Wikipedia] b09d470ab056dffbfb13e4eebf9958fb02e01398 0 824 1673 1672 2013-05-12T04:08:02Z Jsfisher 1 1 revision wikitext text/x-wiki == Common DOE surfaces == === Sinusoidal, triangle === {| |[[Image:Sine.gif|left]]<br> | *Max D.E. ~ 30% +/-1 order *Power distribution follows Bessel function in the scaler region. *T [[Image:Simeq.gif]]&nbsp;[[Image:Lambda.gif]]&nbsp;for transmission. *T [[Image:Simeq.gif]]&nbsp;[[Image:Lambda.gif]]&nbsp;/ 4 for reflection. *Easily replicated or deep etch can yield higher efficiency. |} === Square, rectangle === {| |[[Image:Square.gif|left]] | *Max D.E. ~ 40% +/-1 order. *Power distributions favors odd orders. *Pi phase shift typical. *Classic binary grating. *T [[Image:Simeq.gif]]&nbsp;[[Image:Lambda.gif]]&nbsp;for transmission. *T [[Image:Simeq.gif]]&nbsp;[[Image:Lambda.gif]]&nbsp;/ 4 for reflection. |} === Blazed, sawtooth === {| |[[Image:Blazed.gif|left]] | *Max D.E ~ 98% *Reflection Case: **[[Image:Lambda.gif]]&nbsp;= 2 d sin a **T = [[Image:Lambda.gif]]&nbsp;/ 2 +/- 10% *Transmission Case: **[[Image:Lambda.gif]]&nbsp;= d sin b **a [[Image:Simeq.gif]]&nbsp;2b **T = [[Image:Lambda.gif]]&nbsp;/ (n-1) +/- 10% **Surface shadows reduce D.E. by&nbsp;[[Image:Equ1.gif]] **Wavelength changes reduce D.E. by&nbsp;[[Image:Equ2.gif]] |} == Holographic Deflectors (hologons) == {| |[[Image:Scan.gif|left]]<br> | *N = [[Image:Theta.gif]]&nbsp;D / ( 1.4 [[Image:Lambda.gif]]) *N = number of resolvable spots *[[Image:Theta.gif]] = full scan angle in radians *D = beam diameter in microns *[[Image:Lambda.gif]]&nbsp;= wavelength *[[Image:Phi.gif]]&nbsp;= wedge angle of glass *Special case of linear scan and near wobble invariance&nbsp;[[Image:Invariance1.gif]] max straight scan angle ~ 36 deg</span> *Dynamic wobble&nbsp;[[Image:Dynwob1.gif]] *Wedge wobble = (n-1) [[Image:Phi.gif]] *Scan angle multiplier = 1.4 @ 90degrees cross scan angle |} '''''Last modified on 9/29/97''''' [[Category:Rallison]] 046212e4a75caff1d446376db7e035205f0c0984 0 226 1675 300 2013-05-12T04:08:02Z Jsfisher 1 1 revision wikitext text/x-wiki There is a great deal of equipment available for use in holography. While a hologram can be made with very simple equipment, many holographers have $1000s invested into there labs. The most important piece of equipment is the [[Laser]]. It privides the coherent light source required for making a hologram. In order to steer and shape the beam holographers use [[Mirror]]s, [[Lens]]es and [[Diffuser]]s. More advanced holography is done with 'split beams'. This involves taking the laser beam in splitting it into two or more beams with a [[Beam Splitter]]. A hologram is recorded on a medium. [[Silver Halide Film]] and [[Dichromated Gelatin Chemistry]] are the most common mediums for amature holographers and art holographs. Comercial holograms are usually [[Embossed Holograms]] or [[Polymer Film and Processes]]. Other exotic materials can record a holographic image. See [[Hologram Recording Materials]]. The stability of film is of the upmost importance to recording a hologram. [[Film Holder]]s are designed to hold film stable to 1/2 wavelength of light for the entire exposure time (or better). The polarization of a laser beam can be rotated with a [[Wave Plate]] and this can be quite useful in a large set up. Every optic will contribute noise to the laser beam. [[Optics Aberrations]], dust and fingerprints will leave a mark on the beam quality. In order to clean the beam a [[Spatial Filter]] is used. All of the optics past the first [[Beam Splitter]] need to be held perfectly still. This is acoumplished by designing a [[Optical Bench]] and [[Optic Mounts]] that are very rigid and have no resonances. The exposure time is calculated by using a [[Light Meter]]. Also the ratio of reference to object beam is measured with a [[Light Meter]]. In order to adjust the exposure energy a [[Shutter]] is used to turn the beam on and off. A [[shutter]] can be as simple as a black card removed from the beam by hand or a computer controlled device ===Fringe Lockers=== [[Fringe Locker]]s ===Beam Blocking=== [[Beam Blocker]]s ===Neutral Density Filter=== [[Neutral Density Filter]] 8c591686f5667a7ecebc5208297a21d7f5bec95c 0 228 1677 304 2013-05-12T04:08:02Z Jsfisher 1 1 revision wikitext text/x-wiki ==Some Uses for Everyday Items in Holography== by John Pecora Here are some tips for saving money on ‘lab’ equipment. It is surprising how many everyday objects can be used to good effect in holography. These are just suggestions. Please remember that it is your responsibility to pay attention to safety, and use common sense. *Heating pads used with three or more settings can be used as adjustable heaters for processing trays. Simply put the heating pad under the tray and turn the pad on to the desired setting. *Black foam board can be used for blocking stray light. The type that is black throughout is best as the edges stay black even when they are cut. This material can also be used for making an iris. *A shutter can be made from most old 8mmmovie cameras. They have a low voltage electric shutter. Remove this unit and set up a circuit with the original voltage of the camera, and a switch. *A thick piece of glass, 1/4 inch or thicker, can be used as a beam splitter. Using the thick piece of glass allows a small piece of electric tape to be placed over the glass to block the secondary reflection off the back. *Sandwich boxes can be use as processing trays and also as storage for the chemistry without having to pour the liquids back into bottles after each session. They come in many sizes and shapes with airtight lids. Store sealed containers with chemicals in a dark, dry, cool place when not being used. *Rubber inner tubes can be used as the dampening mechanism between a holographic table and the support legs. *A slab of granite can be used as a holographic table. *Most old overhead projectors contain large front surface mirrors and large Fresnel lenses. They can be purchased at yard sales and flea markets for just a few dollars. *Most photocopiers and fax machines contain front surface mirrors. *New Jefferson Nickels have a weight of 5 grams and new Lincoln Pennies have a weight of 2.5 grams. Standard paper clips have a weight of 1 gram. To verify the weight of the paper clips put a nickel on one side of the balance and find 5 paper clips of the same size that equals the nickel. These can be used on a balance for measuring out chemicals. *A hair dryer can be used to dry a piece of holographic film or plate after processing. Drying intensity and heat is variable with very inexpensive dryers. *Polarizers can be found in polarizing sun glasses. These can be used to adjust the intensity of polarized laser light by inserting the polarizer in the beam path and rotating. They can also be used to check the polarization of light at different locations in an optical set-up. *Two pieces of window pane glass and binder clips can be used to sandwich a piece of holographic film. This will hold the film rigid and flat. *A microwave can be used to warm the deionized or distilled water needed for mixing up processing chemistry. But please be careful to keep chemical-contaminated containers separate and secure. One method is to heat the water in a clean container in the microwave and then pour it into the chemical container for mixing, always keeping the clean container free of any chemicals. *Two-part, fast-hardening epoxy is great for securing two pieces of metal without the need for drilling and tapping. This also allows easy disassembly with just a small sharp blow to one of the pieces. *A pinhole can be made by sandwiching 5 or 10 pieces of aluminum foil together and poking with a pin while the pile is on a hard piece of rubber. Each piece of foil will have a slightly different size of pinhole. *Automobile windshield wiper blades can be used as a squeegee. If you epoxy two blades to a pair of scissors then, when the scissors are closed 3/4 of the way, you can squeegee both sides of the film at the same time. For plates this is not necessary as you can do one side at a time with a single blade. *Clothes pegs on a line can be used to hang up films to dry. After clamping the film at two corners with the pegs, clamp two more at the bottom corners as weights to keep the film straight while drying. *Dishwasher drying agent can be in place of PhotofloTM in the final rinsing bath. Use an agent that does not have fragrance and, preferably, one that is clear. *Sodium carbonate can be purchased cheaply as a chemical for increasing the pH of swimming pools and spas. *Sodium bisulfate can be purchased cheaply as a chemical for decreasing the pH of swimming pools and spas. *Sulfuric acid can be purchased as car battery acid. Most formulas call for concentrations that are lower than that sold as auto battery acid. *Black Sanford Sharpie markers, which come in different sizes, are ideal for blackening optics, mounts and anything small you want to reduce reflections on. They are permanent markers that write on almost anything. *Paper MateTM liquid paper correction is great for painting objects for holography. It dries to a flat white and diffuses the light very well. *A disposable shower curtian works well as a dust protector for a collimation mirror. fe6b24a607672d1089e351c9f6889efc64c58fb7 0 237 1679 322 2013-05-12T04:08:03Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:FDeFreitas.jpg]] [http://www.holoworld.com HoloWorld] Frank started holography in 1983. While having no formal training in science, he has made a career in science and technology. He runs [http://www.holoworld.com HoloWorld], perhaps the most popular web site for holography. He is one of the pioneers of using laser pointers to make holograms. He is the author of "Shoebox Holography" and runs an internet radio program, [http://www.holoworld.com/holotalk/index.html HoloTalk]. He also teaches holography to childeren in workshops. cdaeaf38969ea9ea2ae896c104066cec2660ad32 0 825 1681 1680 2013-05-12T04:08:03Z Jsfisher 1 1 revision wikitext text/x-wiki == The Why, When, and How of Fringe Locking == === WHY LOCK === In any holographic recording set up there is a finite probability that the relative phases of the two or more interfering waves will be perturbed during the time necessary to complete the exposure. Any perturbation at all can affect the final uniformity, brightness and viewing aperture of the recording. Our success as holographers literally depends on how well we can reduce the probability of an untimely relative phase error. In other words we have to stop everything on the table from resonating, creeping, shrinking, distorting, buckling, flowing, rocking, sinking, expanding, bowing, settling, slipping or waving in the breeze. We have to stop the breeze and all its gradients too. Two ways around the problem are to always make only contact copies in thick glass or to only use a Q switched laser source or both. For virtually all other tasks we must do what we can to eliminate any and all sources of air, component or table movement. A wise holographer does his best to stabilize the environment, block drafts and use rigid robust components and then tests the table with a Michelson interferometer. Let me suggest that you test your table by setting up an interferometer with longest possible arms and display the fringes on a screen with a grid on it or if possible place a pair of photovoltaic cells over a fringe and watch the differential voltage change. Do your best to block all sources of error and let everything settle for an hour then watch for fringe drift over 1 to 5 minutes.You may be surprised to see that your best efforts could not prevent the measurable displacement of a fringe over that much time. If you are working with a steel table, try holding your hand an inch or two away from the surface and watch the fringes drift slowly across the screen as the table heats up. A few experiments like this will convince you that there is often a good reason to go to the trouble to electronically stabilize your set up. === WHEN TO LOCK === Persons involved in production transfer type copying can benefit from stabilized setups to get more consistently good copies. Exposing in polymers and resists often takes so long that you would likely get nothing at all if a locker were not used. In less severe cases the use of a locker for exposures of more than a few seconds will always result in a recording of maximum fringe contrast which usually means highest possible signal to noise ratios and highest efficiency. I found that I could not make 8 by 10 reflection transfers into DCG from transmission masters without a locker on line. Most of my experience is with reflection transfers in dichromated gelatin as shown in fig 1 or with the fabrication of first generation HOE elements in sizes up to 16 inches square and exposures up to 20 minutes,(above which time uncompensatable distortion tends to wipe me out in large formats). Fringe lockers are best at compensating for simple linear thermal growth or contraction of a table. They also do well with common vibration problems but cannot do much for a flimsy drafty arrangement. In other words, probably nothing can compensate for incompetence or ignorance of mechanical and optical principles but when all else fails they can make the difference that counts. The Stabilock II fringe locker is available from Odhner Holographics, PO Box 841, Amherst, New Hampshire (PH;(603) 673-8651 or FAX: (603) 673-8685 (Jeff Odhner: &lt;a href="mailto:jodhner@stabilock.com"&gt; jodhner@stabilock.com&lt;/a&gt;)." Jeff now has an RS-232 option for the Stabilock II Fringe Locker with a LabView driver. It is great for hands-off fringe locking applications. The driver will not only allow total control of zero, gain, and damping from the computer ("manual control via mouse") but will also enable the fringe locker to go into an "auto-lock" setup before every exposure so that the system is always optimized. ==== Figure 1a. Reflection Transfers Using a Locker ==== [[Image:Lock1a.gif|center]] ==== Figure 1b. Transmission Transfers Using a Locker ==== [[Image:Lock1b.gif|center]] <span style="line-height: 1.5em;">Some of the problems a locker will not help much with include distorting plates or components, uneven heating of components by absorbed light, random graded air drafts,large drifts in laser frequency and large amplitude vibrations or transients. If you have arranged geometries so that fringes sensed by the locker were generated very near the film plane then a hologram will be formed in the local area in spite of the severe movements mentioned but the rest of the plate will likely be blank, banded or dim.</span> <span style="line-height: 1.5em;" />The allowable movement to get a good recording varies with the kind of recording being made and is best described in terms of a&nbsp;% of a fringe. At 100% fringe movement we get total cancellation but even 10% is going to be noticeable, so our goal should be 1 or 2% max allowable which translates to .004 microns of path length change in the worst case reflection geometry but may only translate to 1 micron in a narrow angle transmission set up. In general the benefits of a locker will be most noticeable when making reflection holograms which tend to be several times more sensitive to path length changes than transmission holograms. Stabilization over many minutes with tolerances of under a hundredth of a micron seem unlikely and unrealistic but that is what is required and that is about what you can get from a well made and properly employed Fringe Locker. === HOW TO LOCK === &lt;u The first step in fringe locking is to get a good look at the fringes that are to be locked onto. They can be magnified at the film plane at the expense of available energy or simply generated near the film plane for easy viewing and sensing electronically. It is very gratifying to be able to easily see with your eyes what is going on in real time so I always have chosen the fringe generation method rather than direct sensing and sampling. I place a beam splitter behind or to the side of the film holder and orient it so that one of the input beams is reflected to be collinear with the other beam. A small cross scratched into the surface of the splitter helps to align the two beams on a screen placed on a distant separate table. Everything is adjusted to get the biggest brightest fringes possible by inserting filters and lenses or picking different ratio splitters as necessary to get the best contrast and size. The locker will do fine with only a 1 mm fringe but I like to have a few fringes blown up to several inches wide on a cross hatched white screen so I can watch even the tiniest quiver or catch a fluttering mode or a mode hop during the exposure.<br> <br> Another very useful method of generating fringes is to make a small hologram in a holder near the film plane and lock onto the moire fringes that result in placing it back in the set up slightly off its original angle. This method presupposes that the set up is stable enough to make at least a weak hologram without a locker so if it isn't then it can be very frustrating. It is a very general method otherwise and can be used with available diffuse image light rather than the strictly locally available specular light needed for the beamsplitter method. I always opt for the beamsplitter when it is possible to get light where I need it but have resorted to the hologram / moire method when I couldn't and find it only slightly more cumbersome. One pleasant benefit is that it always produces straight fringes over a large area whereas the splitter may only yield the distorted center of a zone plate with a single pair of fringes to lock onto and view.<br> <br> The next step may have preceded the first step but not necessarily so. A transducer capable of introducing an optical path length change has to be introduced into one leg of the set up. The common choice is to reflect off a mirror mounted on a piezo bimorph or a speaker coil. Some drivers such as the STABILOK II move a bimorph far enough to be used in transmission mode by translating a wedge or prism to introduce a relative phase shift or optical path length difference, (OPD). If two prisms are used it is not necessary to include the transducer in the original set up prior to finding or generating fringes, the assembly may be pushed into place after the fact with only minor adjustments to prior alignments .<br> <br> The two methods are illustrated in Fig 2. Before making the choice of mounting wedges on your bimorph consider that it moves over about 6 microns which may represent 30 fringes using a mirror at reasonable angles but will be only 7 or 8 fringes when used with a 45 degree prism of refractive index equal to 1.5. OPD equations are given for each configuration where L = the max bimorph travel and n = the index of refraction of the prism. ==== Fig 2. Mirror and Prism Configurations ==== [[Image:Locker2.gif|center]]<br> === SETTING UP THE STABILOK === The final step is connecting and adjusting the electronic hardware. The electronics of the STABILOK II consist of a simple but subtle differential amplifier with a few tweaks for fine tuning. The amp is required to be both stable and high gain, it must not drift over very long periods of time while responding to slowly drifting inputs and an occasional sharp transient or harmonic oscillation. In order to lock with a 20th of a fringe or better tolerance, the gain has to be as high as it can go without running the whole system into instability. The gain control is turned up until the fringes fuzz out and then it is backed off to where they are first clearly visible and solidly locked. The frequency response or damper control may be left up all the way or if vibration is not likely may be reduced or "rolled off" so that gain can be increased even higher to correct even tinier slow drift corrections. I like to tweak all the controls liberally to see how the set up is going to respond. Each set up has its own peculiar resonances and weaknesses which can all be observed if you have generated an easy viewing port away from the set up with large bright fringes. After I get it all tuned up as best I can I stomp on the floor and tap the table and a few suspect components to find and fix any problems with the locker off and then on. Next I let everything settle for a few minutes to half an hour and then begin rapid fire shooting,relying on the locker to compensate for about a fringe worth of movement in every shot. The locker will allow you to significantly increase your throughput as it cuts settling time dramatically in a production set up. I have used by now 6 different fringe locker designs and I really like the newest unit from MEI, the STABILOK II. It has an illuminated scale to let you know if it will work with available light and to center the bimorph travel. The same scale lets you track the action during exposure and even measure the amplitude and direction of the drift. The dynamic range is the range of usable input energies and is very large on this model.The gain is incredibly high which means it will oscillate but it will also lock on very tightly. The stability is better than the spec of a 20th of a wave when care is taken to generate large clean smooth fringes. The sensors are simple , rugged photodiodes in a balanced differential pair and the bimorph is damped and rigidly mounted. Drift is very low without feedback and essentially zero after a lock is made. Monitoring via a strip chart recorder is made convenient from a BNC output connector. === SUMMARY === Fringe locking is often advisable or even necessary. It is only difficult for the first time or two and is usually quite simple to accomplish, requiring at times a little ingenuity and always some patience to generate fringes. The hardware is fairly rugged and laser grade dielectrics or prisms may be used by simply gluing them over the existing mirror. First timers are advised to experiment with their tables in the manner previously described to discover not only how to use the devices but to determine what is moving and what is not in any set up. Since the task is usually to compensate for table growth a separate laser and optical paths running parallel to the holographic set up with one shared mirror may work for you. And last of all, I think experimenting with lockers is even fun sometimes. [[Additional use for Fringe Locker]] '''''Last modified on 8/13/98''''' [[Category:Rallison]] a7a40214327f94ed4c385888bfeb165d3050a9f6 0 244 1683 336 2013-05-12T04:08:03Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:GLippmann.jpg]] French physicist who received the Nobel Prize for Physics in 1908 for producing the first colour photographic plate . He was known for the innovations that resulted from his search for a direct colour-sensitive medium in photography. Though born of French parents in Luxembourg, Lippmann grew up in Paris and was a bright but unruly student. Despite the fact that he never received his teacher's certificate, he was appointed professor of mathematical physics at the Sorbonne in 1883. He later was appointed head of the Sorbonne's Laboratories of Physical Research (1886). Lippman's scientific talents were varied, but he was best known for his contributions in the fields of optics and electricity. He did early, important studies of piezoelectricity (precursors of Pierre Curie's work) and of induction in resistanceless, or superconductive, circuits (precursors of Heike Kammerlingh-Onnes' validations). He also invented the coleostat, an instrument that allowed for long-exposure photographs of the sky by compensating for the Earth's motion during the exposure. In 1891 Lippmann revealed a revolutionary colour-photography process, later called the Lippmann process, that utilized the natural colours of light wavelengths instead of using dyes and pigments. He placed a reflecting coat of mercury behind the emulsion of a panchromatic plate. The mercury reflected light rays back through the emulsion to interfere with the incident rays, forming a latent image that varied in depth according to each ray's colour. The development process then reproduced this image, and the result, when viewed, was brilliantly accurate. This direct method of colour photography was slow and tedious because of necessarily long exposure times, and no copies of the original could be made. It never achieved popularity, therefore, but it was an important step in the development of colour photography. [http://nobelprize.org/physics/laureates/1908/lippmann-bio.html Nobel Prize's Biography of Gabriel Lippmann] b263f6cbbc8d8b6541b90b344f273c27ea052fc8 0 826 1685 1684 2013-05-12T04:08:05Z Jsfisher 1 1 revision wikitext text/x-wiki == Silver Halide Films and Plates == === Workin' out with Irena === {| |- | Tom B.: Same plates and technique as usual (BB-640, 6% TEA, lit for photo with OptiLed amber from about 1.5 m). The pics didn't come out as well this time, but good enough. The fringe pattern under the models is intentional - I calculated a mickey-mouse model of spherical wavefront interference and printed it out on cardstock as a background, but alas it moved a bit so it's dark under Irena's hand. [[File:Olympic.jpg|400px]] Here is a stereoscopic pair photographed from the hologram. Look through the image to get the two halves to merge into a single image. [[File:Olympic_stereo.jpg|400px]] More of Tom B.'s work is show-cased at http://members.shaw.ca/holopix/My_holograms.html, complete with a chronology of his ever-improving efforts. |} === My First... === {| | PeterZ: This is my first reflection hologram using Integraf holokit, with PFG-01. Exposure time was 25s, distance between laser and plate 37 cm. Not very good photo. I'll do another one using polarizing filter and camera with manual focus. [[File:PeterZ_first.jpg|400px]] |} == Litiholo Kit == === Simple Transmission of Car === {| |- | Transmission hologram by Arturo with Litiholo kit. [[File:Arturo_Liti_car1.jpg|250px]] [[File:Arturo_Liti_car2.jpg|250px]] |} == Dichromated Gelatin == === Mermaid === {| | Colin Kaminski: This is a 4x5" dichromated geletin reflection H2 hologram that Dinesh, Joy and I made at their lab in San Diego. Here is a link to their work: http://www.tripletake.com. I helped a little but really the sucess of this image was the result of their skills which they were very generous about teaching me. [[File:Kaminski_mermaid.jpg|400px]] |} === Musical Angel === {| |- | John Pecora: On the left, 488 nm, 30 second exposure, fixer, water, alcohol. On the right, also 488 nm and 30 second exposure, then water for 25 seconds, then fixer, water, alcohol. Both exactly the same except the water prior to fixer soak. If you look on the right near the head in the white hologram you will see a type of whiteness and it starts to blur into the angels head on the white hologram. It seems to be where the emulsion is thin. The emulsion actually seemed to crystalized. It's not that is it cloudy but it reflects the light off the emulsion like a white haze. The more more of an angle the replay light the more diffusely reflecting the haze is and the further into the hologram it moves (all the way over to about half way across the head where it is blurry). Also what I noticed is the hologram on the left, when dried with the hot air just dried and got brighter and shifted colors. The one on the right exhibited that white crystalization (not cloudy) that then cleared up and went away to yield the hologram. [[File:JohnFP_AngelMusic.jpg|400px]] |} === Compass 215M Test === {| |- | Dave Battin plays with his Coherent 215M running at just under 30 mW. This hologram was a 6 minute exposure using one concave mirror, rapid fix. and ''dip sensitizing method''. The dip sensitizing method involves the following: * Coat gelatin onto glass and allow to harden. * Dip hardened plates into solution of AmDi (15 g), H₂O (500 ml), and soapy water (10ml). * Allow to '''air dry'''. * Expose. [[File:Battin_215M.JPG|400px]] |} === Two Color Test === {| |- | Combined red and green beams by Joe Farina. [[File:Farina_DCG_marbles.JPG|400px]] |} === Two Color Figures === {| |- | Joe Farina: These were done with Jeff's MBDCG formula, except that boric acid was used to adjust the pH, and Rhodamine 6G was used as the additional green sensitizer. The exposure was a combined 532/633 beam, with 14mW for 532 and 20mW for 633, measured after the spatial filter, the holograms are simple SBR Denisyuk. Plates are about 5 X 5 inches, and the exposures were around 20 minutes. One of the figures was painted with a few colors (very crudely), and the other figure was painted silver. The silver-painted figure helps me to get a better grip on whether the hologram (as a whole) is more narrowband or broadband. The plate on the right has a serious flaw (but also the best color reproduction) because there is a patch across the lower faces and upper chests of the two figures. This seems to be where the emulsion overheated in the oven. (I made a mistake by laving the glass directly on the inner floor of a homemade oven, I will correct that next time.) The colors came out fine. The outer robe is green, the inner garment is red, the scroll is white, the skin tone is tan, the hair is dark brown, with some lighter brown areas. I'm surprised the scroll came out so white. These two wavelengths (532 and 633) seem to be capable of reproducing a great many colors, but of course anything containing blue won't show up. I'm confident that this exact system will work very well if blue is added, for full color. [[File:Farina_DCG_figures1.jpg|400px]] [[File:Farina_DCG_figures2.jpg|400px]] [[File:Farina_DCG_figures3.jpg|400px]] |} === Little MBDCG Holo === {| |- | Hans: Here is a sample of a MBDCG that I just made with my adjustments to the original MBDCG. Due to temperature/moisture in my garage, I would never have been able to do this in my garage with classical MBDCG as was invented by Jeff Blyth because of fading (crystallizing) of the MB in the plate. Exposure time was 5 minutes with a TEC controlled laser diode. The plate was processed as follows: * First a long wash (10 minutes) in cold water to wash out the chemicals. * A swelling bath at 26C. I found that for thick coatings, this bath needs to be at least one minute. Otherwise, dim areas will appear on the hologram. * 35% IPA at 25C, two minutes * 70% IPA at 25C, two minutes * 99% IPA at 25C, three minutes I use no fixer. Remember that in classic DCG, the fixer is needed to convert the Cr(V) to Cr(III). It is the Cr(III) that hardens the fringes in the gelatin. With MBDCG it is the Methylene Blue that does that job. Cr(VI) is converted directly to Cr(III) upon illumination, and thus eliminating the need for a fixer. In previous experiments I found a great benefit in using a hardener before the swelling baths. But because my hardener was getting old so fast, I started to experiment with post exposures. I found the effect to be similar. I prefer the post exposure method over a hardening bath because it cancels out two big variables: Temperature of the hardening bath and age of the hardening chemicals. With a post exposure there is only one variable: Post exposure time. Experimentally, a post exposure time of 1/7 of the normal exposure time seems to work fine. I just wiggle the plate in the expanded laser beam at about the same distance where the plate was when the hologram was exposed. I have not found a little difference in bandwidth between post exposed plates and chemically hardened plates. Post exposed plates indeed are a little bit more broadband. But that to me is a benefit. [[File:Hans_NewFormula1.jpg|400px]] |} 146ed7c624bd2cd5541610727a89249f4ff25d8d 0 248 1687 344 2013-05-12T04:08:05Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.hmt.com/holography/cherry/cherry.html Web Site] 7c5e221c386a92d9cfa6c7f0ab4dd7f17afe3556 0 249 1689 346 2013-05-12T04:08:05Z Jsfisher 1 1 revision wikitext text/x-wiki Greg Quinn worked at the National Physical Laboratory between January 21st 1974 and September 15th 1985 in the holographic interferometry group (at that time, part of the Department of Mechanical and Optical Metrology). Working under Tony Ennos, Eddie Archbold and finally Dave Williams, he created many display holograms that have been presented both internally and at national meetings since then. Following his time at NPL, he studied biochemistry at Leeds, and gained his Ph.D. in molecular biology at Southampton University. Greg is currently principal investigator of the Mobile Data Visualization Lab at the San Diego Supercomputer Center, at the University of California San Diego. He's married with one son. f5d97ab7d33526c080a4581898ad13cf2f92a773 0 250 1691 348 2013-05-12T04:08:05Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:GFavalora.jpg]] Gregg E. Favalora (Arlington, Mass., USA) *B.S., Yale Univ. (1996) *S.M., Harvard Univ. (1998) *Founder and CTO, Actuality Systems (1997-present) *[http://www.actuality-systems.com Actuality Systems, Inc.] *[http://www.greggandjenny.com/gregg Personal homepage] Gregg Favalora is not a holographer in the traditional sense. Rather, he has focused on the design and development of many three-dimensional display architectures since being bitten by the "3-D bug" in 1988. He holds a BSEE from Yale and a Masters' in Engineering Sciences from Harvard, which he left in 1997 to found Actuality Systems, a firm specializing in 3-D visualization for medical imaging, oil & gas, and entertainment. His research interests include optics, 3-D displays and electro-holography, biologically-inspired electronic systems design and "neuromorphic engineering", and industrial design. In his spare time he wishes he were better at playing the drums and the ancient strategy game of go. In 1996, while a student at Yale, Gregg developed the first parallel raster-scanned 3-D display under the guidance of Prof. Peter Kindlmann. It used 32 laser diodes in conjunction with a polygonal mirror scanner to illuminate a rotating diffuse screen with 32,768 voxels. The autostereoscopic, full-parallax volumetric image occupied roughly egg-sized volume. It is described in U.S. Pat. 5,936,767 and has been in operation - through at least 2006 - in Becton Center at Yale University since 1996. In 1997, Gregg founded Actuality Systems to develop software and opto-electronic systems for true 3-D visualization. In 2001, Actuality's engineers developed the world's highest-resolution volumetric 3-D display. Now marketed under the name Perspecta(r), it generates 10"-diameter 3-D imagery by projecting patterned light at 6,000 frame/s onto a swiftly rotating diffuse screen. The imagery created by Perspecta is composed of approximately 100 million voxels. Through 2006, Actuality's innovations include: "Spatial Visualization Environment," the world's first software platform that interprets graphical data from standard applications and processes them for displays of a wide variety of underlying physics, such as multiplanar displays, holographic displays, and highly-multiview displays. With a team including Oliver S. Cossairt, Rick K. Dorval, and Sam Hill, showed that it is possible to create a volumetric display with voxels having viewer-position-dependent effects, such as variable opacity. Developed several quasi-holographic "aerial" display systems that project free-floating imagery measuring 1" x 1" x 1" to 6" x 6" x 3". Working with leading hospitals to use volumetric 3-D displays for the review of cancer therapy plans using radiation oncology. Gregg is an inventor or co-inventor on: *U.S. Pat. 5,936,767, "Multiplanar autostereoscopic imaging system" *U.S. Pat. 6,183,088, "Three-dimensional display system" *U.S. Pat. 6,487,020, "Volumetric three-dimensional display architecture" *U.S. Pat. 6,512,498, "Volumetric stroboscopic display" *U.S. Pat. 6,570,681, "System and method for dynamic optical switching" *U.S. Pat. 6,940,653, "Radiation conditioning system" Gregg is a winner of the 1996 National Inventors' Hall of Fame / BFGoodrich Collegiate Inventors Award, is a member of the MIT Technology Review "TR-100" young innovators, and is a frequent speaker on the topic of entrepreneurship. Due in large part to the efforts of Actuality's engineers, his work has appeared in the Wall Street Journal, Wired, CNN Headline News, and a variety of major technology and medical publications around the world. 3c0bf31a507e99d41d9ea79633321e538a3af96e 0 827 1693 1692 2013-05-12T04:08:05Z Jsfisher 1 1 revision wikitext text/x-wiki === Description, Use and Construction of the HOEs in this Kit === &lt;a href="http://web.archive.org/web/20080706200158/http://www.xmission.com/~ralcon/main.html#ordering"&gt;Ordering Information&lt;/a&gt;<br> ''Price per RK8 kit: $96 plus $4 S+H<br> Price per individual HOE: $20 incl S+H<br> We accept orders by company POs, phone, e-mail or fax.<br> Pay by Check, VISA/MC, C.O.D., Cash or Barter.<br>'' For inquires of any kind, contact lab director {| border="1" |- | [[Image:h1.gif]] | Off Axis Interferometric Zone Plate (IZP) - This unit has a focal length of 25 cm @ 633nm and reconstructs with a collimated wave introduced 20 degrees off axis. The focused spot will appear 20 degrees off axis also for a total diffraction angle of 40 degrees. It was made @ 488 nm but has few aberrations because it was contact copied from a master that was made at 633 nm. The master was made in a silver grain film that was cleared and processed like dichromated gelatin (DCG) to reduce scatter at the copy wavelength. The copy is in 8 microns of DCG sandwiched between two pieces of thin glass. |- | [[Image:h2.gif]] | Planer Gratings, Low Spatial Frequency - These units are made by interfering two collimated waves at small angles. The small angle low spatial frequency samples, (approx 100 l/mm) diffract with many orders present over a few degrees. They are similar to sinusoidal surface phase gratings in power spectrum and exhibit only a small Bragg selectivity. The power distribution is a function of the phase modulation which is in turn dependent on the available index modulation. As the spatial frequency goes above 500 l/mm the Bragg selectivity becomes strong and a single order dominates. These gratings are made in DCG in the range of 12 to 20 microns and each one is an original or first generation grating exposed at 488nm. |- | [[Image:h3.gif]] | Planar Gratings, High Spatial Frequency- A spatial frequency is considered high when the grating spacing is about equal to the wavelength being used. In the visible region this is around 2000 lines/mm. Higher orders are either not possible or are very weak in this range and diffraction efficiency is dependant on polarization as well as modulation, thickness, wavelength and angle. Volume phase gratings can also suppress higher orders even at low spatial frequencies if the thickness is many times the grating spacing. If it is thick in this sense it is said to have a high Q. The sample in this kit would be considered medium thick at 5 to 8 microns and of moderately high frequency at 2234 l/mm. |- | [[Image:H4.gif]] | Blazed Binary Optic Array - This is a set of six small blazed zone plates. Two of them are negative with focal lengths of 25 cm and two are positive with the same focal length. The other two are positive with focal lengths of about 75 cm. These were computer generated using a custom program written in POSTSCRIPT language which we call ZONE. The program writes a geometric zone plate pattern and fills the region between zones with up to 20 shades of grey which are printed as variations in dot density at 300 or 600 dots per inch. The output on paper was photoreduced in a common 35 mm NIKON camera using KODAK 5052 TMX negative print film. The next step was to expose a 3 micron layer of photo resist with a mercury arc lamp through the negative master which produced the desired positive blazed phase pattern. The resist master was then replicated in epoxy and the embossed copies in this kit were made by chemically softening a piece of cellulose acetate and pressing it against the epoxy master to cast a positive impression. The originals were 8 inches in diameter but were reduced about 30 times in the camera. The 25 cm focal length was generated by plotting 45 zones with 10 shades of grey and the long focal length came from a print of 15 zones with 20 shades of grey. The surface roughness is from contamination on the photo resist and will unfortunately scatter some of the input light and some moire artifacts are visible indicating that we should print the originals at a higher resolution than 300 dpi. The dispersion is low due to the small number of zones copied so white light may be used with these optics. Blazed zone plates exhibit good first order efficiency when the blaze depth produces a full wavelength of phase shift. These samples are close to correct and have very weak second orders at shorter focal lengths as well as fairly low minus first order. Outputs are easily observed on a white card by imaging a clear light bulb at a distance greater than 2 meters. |- | [[Image:h5.gif]] |Powered Holographic Reflector - These optics are produced by interfering a plane wave on one side of the film with a spherical wave from the other side. They are convex mirrors on one side and concave on the other. The micro structure resembles a layered reflective zone plate, the layers give it wavelength selectivity in the same fashion as a multilayer dielectric laser mirror and the zones give it angular dispersion. If there are many uniform layers or planes then a narrow spectral band is reflected and dispersion is only observed as an artifact in the transmitted light. The unit found in this kit is one of fairly short focal length and is easy to use in white light to observe off axis aberrations. It is not very narrow band and will show both longitudinal and lateral dispersion. The DCG is about 8 microns thick and has been processed to have a chirp in the spacing of the planes as well as a gradient in the index of modulation. The processing makes it behave as if it were thinner than it is. |- | [[Image:h6.gif]] |Conformal Holographic Reflector - These devices have no dispersion but can be made to have bandwidths of from 8 to 200 nm by choosing the appropriate thickness and process. They are in every way nearly identical to multilayer dielectric coatings. As the angle of incidence goes off normal the reflected wave goes toward the blue. The unit in this kit is a medium bandwidth reflector made in an 8 micron layer of DCG by the "air gate" method. It was held in laser light by hand in such a way that some of the light passing through would reflect back on itself at an angle and produce planes conformal to the film surface. The unstable hand holding is sufficient to spoil the spatial coherence of the laser resulting in a stable interference pattern only in a small volume near the film surface. This effectively suppresses the formation of diffracting structures that would otherwise result from multiple surface reflections. These devices are sometimes called notch filters. |- | [[Image:h7.gif]] |High Gain Holographic Diffusing Screen - These are projection screens that have precisely defined energy windows. The projected image is only visible and bright when it is originating from the correct angle and is of the correct wavelength. Even then it can only be seen when the eyes are positioned in the energy box or output pupil of the system. Otherwise it is a slightly hazy piece of clear glass. These units are made by projecting a diffuser through an aperture onto the film from one side and then introducing an appropriate reference wave on the other side. The reference wave for this sample was converging to a point about half a meter away. At arms length it should produce a bright eye box when illuminated with a white light diverging from a point just out from the right shoulder. This is an effective screen for stacking visual inputs since it is nearly invisible when not illuminated correctly. It also concentrates the projected light in a small area making possible the use of lower power projection sources. The sample in this kit is made in 8 microns of DCG at 488nm and processed to reflect green light. |- | [[Image:h8.gif]] |Holographic Scanner, 'One Shot'- This is a small 8 facet deflector intended for use in a hand held Bar Code Scanner. At 633 nm it accepts an input beam 5 degrees off normal and diffracts at 30 degrees off axis where it focuses at 4 different ranges between 200 and 400 mm from the deflector. It is unique in that it can be copied at 488 nm with a single on axis exposure. The master was made one facet at a time at 633 nm in Agfa film and converted to a clean gelatin hologram. Copies are made in DCG of about 5 micron thickness. The thin film and low spatial frequency results in low angular and polarization sensitivity over the scanned angle but also causes losses to a negative order. It can be glued to the end of a stick or mounted on a motor to demonstrate how a section of a zone plate can deflect light. |- | [[Image:h9.gif]] |Optical Interconnect HOE, -Any optical device that connects a source of photons with one or more detectors is an optical interconnect. In electronic circuits, clock pulses are sometimes made to modulate a diode laser which in turn broadcasts the pulse through free space to other parts of the device or circuit. The optical interconnect included in this kit is of appropriate dimensions to connect circuit boards or components on a board with each other. It is of a general design, made up of individual gratings or zone plates arranged side by side or "spatially multiplexed". It could connect a clock laser with 40 detectors, however it was originally designed to address angularly multiplexed pages in a photorefractive Holographic memory. Again this HOE has been fabricated from 10 microns of gelatin, in a sandwich of two pieces of glass. The method of construction was simple step and repeat, the machinery used to change angles between exposures is made from precision rotary tables and a single mode fiber optic system. The fiber is easily positioned any where in space to serve as a point source and it carries blue-green light from an Argon laser which is necessary to generate fringes in the gelatin. Plane Gratings have been formed in the sample but plane or powered reflectors are also possible to form with the same hardware. The gelatin is thick enough to allow volume multiplexing of each individual cell. As many as 25 individual overlapping exposures have been made in this film with only a small change in angle between exposures. This HOE can act like a faceted lens that has been cut in half and glued back together to yield two focused spots. The forty facets will cause an incoming plane wave to divide into two sets of 20 little plane waves that cross at two common planes about 38mm from the HOE surface. Encoding of information and images can be done with this type of HOE where the encoded information only appears on a specifically designed plane at a certain distance and with a certain color of light. Certain kinds of matrix operations can be made with combinations of these Hoes combined with spatial light modulators. Variable or reconfigurable interconnects may be made with the same components. |} '''''Last modified on 10/1/97''''' [[Category:Rallison]] 7e421f28bf576c7d00c39811da444ed8ae7d15a6 0 828 1695 1694 2013-05-12T04:08:07Z Jsfisher 1 1 revision wikitext text/x-wiki ==== Diffractive Optics Family ==== [[Image:Doptics.gif|center]] ==== What can you do with a wavefront? ==== {| cellspacing="5" |- valign="top" | [[Image:whatdo1.gif]] | [[Image:whatdo2.gif]] |} *Diffractive elements can be single-order or multi-order *Patterning resolution x Area (SBWP) is a measure of absolute design freedom *Phase encoding techniques provide the effective design freedom *Very large SBWP can be made by combining holographic recording with computed DOEs ==== Diffractive Optical Element Basic Functions ==== [[Image:does.gif|enter]] ==== Application Examples ==== *Beam-combiners for display systems *Laser scanners *Low noise and high performance diffraction gratings *Asphere testing elements *Spectral notch filters *Holographic laser optical heads *Optical interconnections in microelectronics *Wavefront sampling *Wavefront transformation-diffusers *Solar concentrations *Wavelength multiplexers/demultiplexers *Various unique laser optical elements ==== HUD with combiner laminated into the windshield for Volkswagon ==== [[Image:car.gif|center]] ==== Multi Order Super HOE Scanner ==== [[Image:suprhoe.gif|center]] ==== Potential Advantages Of Holographic Disk Scanners ==== *Simpler optical arrangement *Larger tolerances for wobble *Less air turbulence *Each facet can have a different focal length *Lower production cost per unit *Scan angle is independent of the number of facets ==== Aberration-Corrected HOE Grating For Spectrometer ==== [[Image:abrcorfs.gif|center]] ==== Interferometric Testing With A Computer-Generated Hologram ==== [[Image:comgenho.gif|center]] ==== Spectral Filters ==== [[Image:spctfltr.gif|center]] '''Advantages of Holographic Spectral Filters''' *Easy fabrication of large filters *High efficiency *Parallel layering is not a constraint *Free from extranious passbands ==== Colour Combination/Colour Separation ==== [[Image:colour.gif|center]] ==== Three Beam Optical Pickup For Compact Audio Disk Player ==== [[Image:cdplayer.gif|center]] ==== Optical Interconnections in Microelectronics ==== [[Image:opintmcr.gif|center]] ==== Fiber Optic Couplers ==== [[Image:fiberopc.gif|center]] ==== Wavefront Sampling of High Power Laser ==== [[Image:hipowlsr.gif|center]] ==== Wavefront Transformation System ==== [[Image:wavetran.gif|center]] ==== Faceted HOEs ==== [[Image:faceted.gif|center]] ==== Directional Diffusers ==== [[Image:dirdiff.gif|center]] ==== Solar Applications ==== [[Image:solarapp.gif|center]] ==== Wavelength Multiplexing/Demultiplexing ==== [[Image:wavelngt.gif|center]] ==== The Basic Optical Processor ==== [[Image:basoppro.gif|center]] ==== Anti-Reflective Structures ==== [[Image:antiref.gif|center]] *As the grating period gets smaller, the diffraction angles increase *Ultimately, gratings have only zero order transmitted and zero order reflected *Tailoring duty cycle and etch depth one can control the power in these two remaining orders *This is the same as an impedance match in electricity and magnetism ==== Concept For Holographic Night Goggles ==== [[Image:niteggls.gif|center]] ==== Holography ==== '''Advantages''' {| |- |[[Image:holo1.gif|center]] | *Images to a point with no aberrations *Aberration control possible *Highly dispersive *Optical power on a flat surface *Off-axis geometry *Can be transmissive or reflective *Narrowband response *Can be replicated |} '''Disadvantages''' {| |- |[[Image:holo2.gif|center]] | *High dispersion *Large aberration away from construction conditions *Efficient over small wavelength band *Limited design flexibility *Difficulty with control of holographic emulsions |} ==== Advantages of HOE Diffraction Gratings (HOEDGs) ==== {| border="1" |- ! <u>Property</u> ! <u>Classical Gratings</u> ! <u>HOEDGs</u> |- valign="top" | Efficiencies | 60 to 99% | 50 to 90% (surface relief only)<br>Efficiency at blaze is lower but the efficiency curve is flatter |- valign="top" | Ghosts | At best 10^-5 (usually 10^-2) of parent line | No ghosts at all |- valign="top" | Scattered light | At best 10^-5 to 10^-6 at 5Å of laser line in visible | At best 10^-6 to 10^-8 at 5Å of laser line in visible |- valign="top" | Size | In general standard sizes are limited to 8x8" | Up to [[Image:phi.gif]] 17", but can be larger |- valign="top" | Number of grooves | Maximum 3600 lines/mm (There are rare exceptions.)<br>Scattered light increases drastically with density | Up to 6000 lines/mm<br> No increases of scatter with groove density |- valign="top" | Optical power | No | Yes<br>Volume HOEs can diffract 99% @ Bragg angle and center [[Image:lambda.gif]]. |} ==== Single Element Dispersions Showing Hybrid Achromat Possibilities ==== [[Image:sngledis.gif|center]] ==== Comparisons of Fabrication Methods Of Diffractive Optics ==== {| border="1" |- ! <br> ! Diamond Turning ! Direct-Write ! Holographic or Photo-Lithography ! Embossing ! Injection Molding |- ! Practical production volumes | 10⁰ ~ 10² | 10⁰ ~ 10² | 10⁰ ~ 10⁵ | 10³ ~ 10⁵ | 10³ ~ 10⁷ |- ! Initial tooling costs | low-moderate | low | moderate-high | low-moderate | high |- ! Precision | low-moderate | good-excellent | excellent | moderate | moderate |- ! Materials | metals, plastics | glasses, semiconductors | glasses, semiconductors | plastics | plastics |- ! Volume production costs | high | high | low-moderate | low | low |} ==== Direct Laser Writing ==== [[Image:dir.gif|center]] *Spot sizes ~1 - 5um *Tightly Focuses, modulated He-Cd or Argon-ion laser scanned across photresists surface *Up to 256 phase levels *Serial Process *Difficult to accurately transfer structure into substrate *Direct ablation of polyimide layer on substrate using an excimer laser is also possible *Pattern can be transferred to a VHOE by processing in a 4f optical processor. ==== Photoresist Processes For Lithography ==== [[Image:photo.gif|center]] ==== Spin Coating Photoresist ==== [[Image:spincoat.gif|center]] ==== Replication Methods ==== [[Image:repmeth.gif|center]] ==== 3 Step Conversion of Volume HOE to Surface Blazed HOE ==== [[Image:3step.gif|center]] ==== Laboratory Optical Test Apparatus ==== [[Image:labtest.gif|center]] ==== Rotating Slit Scanners (Beam Scan) ==== [[Image:rotslit.gif|center]] *Narrow, rotating slit is scanned through pattern *Measure irradiance profiles with ~micron lateral precision *Slit widths down to 1 um *Scan areas over 10 mm are possible *Measurement of both near and far-field diffraction patterns *Both 1-D and 2-D scans can be performed ==== Scatterometer ==== [[Image:scattm.gif|center]] *Measures irradiance patterns from DOE's by scanning a detector and pinhole *Scanning and data acquisition is computer controlled (LabView™ software) *Precision depends on pinhole size and step-size of motorized stage *Slow process *Can be difficult to align scan axis ==== Ronchi Rule -- Gaussian Spot Sise Measurement. (Lee Dickson) ==== [[Image:ronchi.gif|center]] *do = 1/e² spot *w = bar width *K = pmin/pmax *do/w = 2.2K + 1 Side view of ruling in beam ==== An Electromagnetic Shutter From A D'Arsenual ==== [[Image:shutter.gif|center]]<br>Shutter is silent and can easily be configured to close after accumulating a preset energy per unit area. ==== Hologram Exposure -- Single-Beam With Nonconformal Mirror ==== [[Image:nncnmirr.gif|center]]<br> Introduced by Yuri M. Denisyuk in early 1960s. ==== Single Beam Frame Using All Second Surface Mirror Without Ghosts (from Saxby) ==== [[Image:brewster.gif|center]] ==== Lloyd's Mirror ==== [[Image:loydsmir.gif|center]] ==== Gravity plateholder (after Abramson⁹ For NDT Apps ==== [[Image:gravity.gif|center]] ==== Film Holder With Xylene Well (after Benton, 1960s) ==== [[Image:filmhold.gif|center]] ==== Full-Aperature Transfer Hologram ==== [[Image:focusopt.gif|center]] ==== Rainbow Hologram (Benton, 1965) ==== [[Image:rainbowh.gif|center]] ==== Holographic Stereogram, after DeBitetto, 1968-69 ==== [[Image:debiteto.gif|center]] ==== 35 mm Holocamera by David Rowley ==== [[Image:holocam.gif|center]] ==== Contact Printing (copying) Of Transmission Or Reflection Holograms ==== [[Image:ctcprnt.gif|center]] ==== Secondary Holograms Formed By Scattered Light In A Construction Beam ==== [[Image:secndary.gif|center]]<br> Any stray or scattered light can combine with a construction beam to form secondary transmission and reflections holograms ==== Secondary Holograms Formed By Surface Reflections ==== [[Image:surfrefl.gif|center]]<br> The reflection portion of construction wave 1 combines with construction wave 2 to form a Transmission hologram ==== Prevention Of Secondary Holograms Formed By Surface Reflections ==== [[Image:orevsd.gif|center]] ==== Spurious (secondary) Holograms ==== [[Image:spurius.gif|center]] *Desired hologram: **Reflection hologram AB *Spurious holograms: **Reflection hologram AA1 **Reflection hologram BB1 **Reflection hologram A1B1 **Transmission hologram AB1 **Transmission hologram A1B ==== Prevention of Secondary Holograms ==== [[Image:prvntsho.gif|center]] ==== Michaelson Interferometer, Table Check, Fringelocker Check ==== [[Image:micinter.gif|center]] ==== Unique Characteristics Of HOEs ==== *Perfect imaging between two points for a single wavelength *Useful in unusual (I.E., not in-line) geometries *Shape independent (I.E., flat surfaces can have optical power) *Extremely dispersive (effice v-number of -3.45) *Angle selection *Wavelength selective *Multiple functions *Multiple elements in the same aperture *Compact and light weight *Relatively inexpensive - low cost "photographic" replication ==== Requirements on Construction Optical System ==== *Hight quality optical elements *Minimize multiple reflections between surfaces of construction optics and hologram substrate *Scattered light should be prevented from falling on hologram plate *Mechanical and thermal stability during exposure *Proper coherence length *Polarization of two recording beams should be maintained properly *Active fringe stabilization system for long exposures ==== Form Birefringence ==== [[Image:birefrin.gif|center]] *Subwavelength gratings behave somewhat like biaxial crystals *As the period gets small relative to the wavelength, we can calculate an equivalent dielectric constant or index of refraction (n) ''Last modified on 7/21/99'' [[Category:Rallison]] ea080d11d3b9368b93fd57997704e0f133f95e53 0 255 1697 358 2013-05-12T04:08:07Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:HBjelkhagen.jpg]] Dr Hans I. Bjelkhagen, professor of Interferential Imaging Sciences, with North East Institute for Higher Education, Wrexham, at the Centre for Modern Optics located in OpTIC Technium in North Wales, UK. He received his PhD degree in 1978 from the Royal Institute of Technology in Stockholm, Sweden. There he developed methods for recording interferometric holograms and performed holographic nondestructive testing for the Swedish car and airplane industry, e.g., VOLVO and SAAB. In addition to industrial applications of holography, Dr Bjelkhagen specialised in medical and dental holographic recordings. Dr Bjelkhagen has developed a holographic recording system for dental casts. The equipment: HOLODENT SYSTEM was produced and marketed by Dentatus International AB in Sweden. He has also invented and patented a special method to detect caries lesions (tooth decay) at an early stage based on laser fluorescence. Currently, a quantitative clinical system based on that patent is being developed and marketed by INSPEKTOR Research Systems bv in Amsterdam, the Netherlands. In 1983, he joined CERN in Geneva, Switzerland, where he was involved in development of bubble chamber holography. A year later he participated in an international team working on neutrino physics experiments recording holograms in the 15-foot bubble chamber at Fermilab in Batavia, IL, USA. Between 1985-1991 he was at Northwestern University, Evanston, IL, working on medical endoscopic applications of holography. He developed methods of recording in-vivo holograms at the tip of a special fibre-optic endoscope. Dr Bjelkhagen has been involved in the development of a large autostereoscopic computer display system when working for American Propylaea Corporation and Intrepid World Communications in Michigan. The project was carried out between Propylaea and US Army Tank Command, Warren, MI, through a CRDA (A Cooperative Research and Development Agreement). The work resulted in a prototype based on a 30" by 50" projection HOE and an array of single-lens video projectors and run by Silicon Graphics ONYX computers. During the last ten years, Dr Bjelkhagen has been most recognized for his work in colour holography, holographic recording materials and Lippmann photography. Dr Bjelkhagen has been able to demonstrate that high-quality full-colour holograms recorded in "white" laser light (combined RGB light from three laser wavelengths) could be stored in a single-layer ultra-high-resolution silver halide emulsion. In December 1997 Dr Bjelkhagen was invited by Professor Nicholas Phillips to join him at the newly established Centre for Modern Optics at De Montfort University, Leicester, in England. There he continued his research on 3D imaging, colour holography, colour HOEs, holographic recording materials, and Lippmann photography. Currently, a new optical variable device (OVD) based on the one-hundred-year-old Lippmann photographic colour recording technique is being developed. The application is in the field of optical document security. Individually recorded OVDs, similar to reflection holograms, can be applied to documents, such as, passports, ID-cards, driver’s licenses, etc. At the Centre for Modern Optics he has been involved in projects supported by companies, such as, SAMSUNG and SHARP. In addition to his scientific 3D coherent imaging Dr Bjelkhagen is a well-known holographer who has recorded many holograms for 3D display purposes. From his early years in holography he has been involved in large-format, high-quality display holography both pulsed and cw laser holography. He has recorded many unique art objects, such as, e.g., the Swedish Coronation Crown of Erik XIV (from 1561) in 1974 and the Chinese Flying Horse from Kansu (from 100 A.D.) at an exhibition in Stockholm in 1976. Dr Bjelkhagen has been working with several famous artists, for example, Carl Fredrik Reuterswärd, creating holograms exhibited in many art museums and art galleries around the world. Dr Bjelkhagen has specialized in pulsed display holograms, in particular, holographic portraits. He has recorded holograms of many people the most famous one being President Ronald Reagan, a portrait recorded May 24, 1991. This is the first and, so far, the only holographic portrait recorded of an American president. One copy of the holographic portrait is in The National Portrait Gallery of the Smithsonian Institution in Washington DC. When Dr Bjelkhagen was working in the USA in the 80s and 90s, he started two holographic companies together with two of his colleagues in Chicago. One company was HOLICON Corporation, a company specialised in large-format pulsed holography and portraiture. Among the interesting projects can be mentioned a promotional project for Bristol-Myers Squibb Company: "The Gallery of the Pathogenesis of Atherosclerosis" using hologram of microscopes through which arteries could be studied. After the campaign was over, the holograms were donated by Bristol-Myers Squibb to museums in the USA, for example, the Museum of Science and Industry in Chicago, where the holograms are still on display. HOLICON was also financially responsible and provided equipment for recording the 1991 holographic portrait of President Ronald Reagan which took place at Brooks Institute of Photography in Santa Barbara in California. The other company, Holographic Industries Inc., operated several Lightwave Hologram Galleries, marketing holograms and other holography-related products and located in US cities such as, e.g., Chicago, Detroit, and San Francisco. Dr Bjelkhagen has published over 100 papers in refereed journals and conference proceedings and holds 9 international patents. However, his most important academic contribution is the Springer book on Silver-Halide Recording Materials for Holography and Their Processing. That book considered to be the standard textbook on the subject is now used in many of the universities teaching holography as well as in most worldwide companies producing display holograms. Bjelkhagen is a member of the Optical Society of America (OSA) and a Topical Editor of the society's journal Applied Optics. He is a fellow the International Society for Optical Engineering (SPIE) and the co-chairman of SPIE's Holography Technical Group. He is an Accredited Senior Imaging Scientist and Fellow of The Royal Photographic Society (RPS). Bjelkhagen received the RPS SAXBY AWARD in 2001 for his work in holography. *2004 - present Professor, Interferential Imaging Sciences North East Institute of Higher Education, Wrexham, and Centre for Modern Optics at OpTIC Technium, St. Asaph, Wales *2001 -2004 Professor, Interferential Imaging Sciences, De Montfort University, Leicester, England. *1997 - 2001 Senior Research Fellow, Modern Optics De Montfort University, Leicester, England. *1996 - 1997, Visiting Research Scientist, Lake Forest College, Lake Forest, Illinois, USA. *1994 - 1995, Vice President - Research & Development, American Propylaea Corp., Birmingham, Michigan, USA. *1992 - 1994, Visiting Professor, University of Münster, Germany. *1985 – 1992, Associate Professor, Biomedical Engineering, Northwestern University, Evanston, Illinois, USA. *1985, 1991, Associate Professor, Applied Photonics, Louis Pasteur (6 months each University, Strasbourg, France. *1984 1985, Visiting Research Associate, Fermi National Accelerator Lab, Batavia, Illinois, USA. *1983 1984, Visiting Research Associate, CERN (European Organization for Nuclear Research), Geneva, Switzerland. *1978 1983, Associate Research Professor, Production Engineering, Royal Institute of Technology, Stockholm, Sweden. *1969 1978, Research Assistant, Production Engineering, Royal Institute of Technology, Stockholm, Sweden. Swedish citizen, UK resident, US Green Card Holder, Date of Birth: March 9, 1945, Stockholm, Sweden. 7a944325261a7a59821e9f838a2f8cbfea485bf2 0 258 1699 364 2013-05-12T04:08:07Z Jsfisher 1 1 revision wikitext text/x-wiki == Hart Perry == During the last 30 years working as a filmmaker, Hart Perry has carved out three distinct reputations: social and music documentarian, cameraman and artist. In 1969 he was the youngest cameraman at the legendary Woodstock music festival and in 1970 he directed his first music video, "Alice Cooper." In 1977, he was the principal cinematographer of the award-winning documentary "Harlan County, U.S.A." During the 1970s and 1980s, Perry was a innovative force in the development of holographic movies (Integral holographic stereograms). Working with a grant from the National Endowment for the Arts in 1977, he built the second optical printer for producing holographic movies in the world. As President of the Holographic Film Company (New York), he worked on commercial applications for holographic movies in the areas of advertising and portraiture. In addition, he was the Director of the Cabin Creek Center's Artist-in-Residence program, funded by the National Endowment for the Arts and the New York State Council on the Arts. This program represented the innovative collaborations of holographies with visual artists, sculptors and dancers. In creating holographic movies, Mr. Perry converted 16mm film footage to holographic film to capture both motion and dimension. The holographic film was then wrapped inside a Plexiglas cylinder and illuminated for viewing with a normal light bulb. This process was invented by Lloyd Cross in 1972. His holograms of computer generated images produced in the early 70s were innovative and have been widely exhibited in museums and art galleries. In addition, he produced holograms for Salvador Dali, Milton Glazer, Mabou Mimes, Agam and other artists. [http://www.perryfilms.com/hart.html] 775a4f686669bc313f7522671f2aa59579dcc242 0 829 1701 1700 2013-05-12T04:08:08Z Jsfisher 1 1 revision wikitext text/x-wiki Richard D. Rallison == Abstract == The term "dichromates" may have started with Lloyd Cross, all I can recall is that I traded him a pocket full of "dichromates" for a "kiss". We were at the school of holography on the Santa Monica beach at the time. The first recording in Dichromated gelatin that I was privileged to see was made a year earlier by Mike Foster in the city of salt and he may also have used the term "dichromates". Mike and I were both working rock concerts in Utah from about 1965 to 1972 and got together from time to time to discuss science stuff and in particular an article in Popular Science written by Harry Knowles of Metrologic Instruments detailing the procedures for making a simple transmission hologram. I helped Mike prepare a lab and he made the first silver grain hologram I had ever seen. He chose a metal pig borrowed from the desk of weird Harold, who paid for everything at the time. I set up my own sand box lab after that, studied as many holography papers as I could find, made phase gratings, wrote my first paper on holographic gratings and then moved to LA to work at Hughes as an EE. A year later, 1974, I began production of the first dichromate jars, followed by the ubiquitous dichromate pendant, watch face, key fob and belt buckle in 1976. At my first SPIE meeting in San Diego in 1977, I sold dichromates in the halls. I carried a briefcase full of pendants with a covered display on the outside. Sales were brisk and I often had to retreat to my van to restock the briefcase. SPIE policy forbade such activity so I had to move around a lot to avoid Sue Davis. That was pretty much the beginning of a cottage industry. == Hooked on Optics == This paper is a brief journey from my first introduction to display optics to a career in holography. It is anecdotal experiences more or less presented in order of occurrence and has no technical merit. It represents my best effort at story telling and may not even be accurate. My journey began at the New York world fair of 1965 at the General Electric exhibit. GE had constructed a huge color organ using Rolux multi-lens sheeting to give the back lit screen a three dimensional appearance. I went home to Utah for my second year at USU and duplicated the device with help from a GE engineer and began selling them to bars. In 1966 I saw my first professional light show produced by Jerry Abrahms called "head lights" and quickly copied his equipment and made up some new effects of my own. Fred Unterseher was a part of Jerry's crew. I had built a large color organ in the likeness of an umbrella over the audience and so I called my show the "Electric Umbrella", a name I continued to use through my early years in holography. This was really fun stuff, I used colored oils and colored water between large clock faces to make dynamic amoeba looking projections onto screens, walls and ceilings. I cut holes in colored gels and rotated them slowly in front of de-focused slide projectors to create a flowing, ever changing colorful background and then superimposed sharp exploding images strobed by faster wheels and multiple projectors. Then I made slides from birefringent tapes and spun polarizers in front of projectors and I had built a few strobe lights from surplus electronics to annoy everyone with. I was probably born to be a photon junkie. {| border="1" |- | [[File:RDRLightshow.jpg]] | [[File:RDRFred77.jpg]] |- | RDR in 1967, operating a light show projector, (oils), in a very tiny projection booth. | Fred Unterseher in 1977, San Diego SPIE |} === Mike Foster === There was another light show operator in Utah at that time and I managed to meet him sometime during or between gigs. He was a fascinating and very sharp character named Mike Foster and his show was known as "five fingers on my hand". He had all the right stuff and knew how to use it and his connections were good. Eventually he helped me get a gig with the Steve Miller band in Feb of 1969 and allowed me to play with his new He Ne laser at a Pink Floyd gig in about 1970. Light shows went all Laser sometime after that and our projector based shows faded out. In 1972 I was building my first dye laser and Mike had just built an Argon laser (neither laser ever worked). One day he brought in a copy of Popular Science that had an article on how to make a hologram. We built a little black room and placed a granite slab on an inner tube and he made a hologram of a metal pig, borrowed from weird Harold's desk.. I thought it was cool but he saw a future in it. I continued on with EE studies and graduated and moved to LA to work at Hughes where I could play with more lasers and maybe make some that worked. My first trip back to Utah to ski I stopped in to see mike and he had made an 8 x 10 dichromate of David and finally I saw a future in holography. I had done some initial library research on all that was published up to 1973 and had passed it on to Mike and he had reproduced literally everything and already had developed proprietary and novel methods of making embossing masters. He was way out there. {| border="1" |- | [[File:RDRMikef.jpg]] | [[File:RDRLloyd.jpg]] |- | Mike Foster about 1976, SLC | Lloyd Cross 1977, San Diego |} === The early dichromate pioneers === In October 1968 T A Shankoff of Bell Labs published the first dichromated gelatin paper followed quickly by L H Lin, then Brandes and Curran also from Bell Labs. The reporting was quite complete and laid the groundwork for all other investigators. In 1971 Milton Chang of Northrop published an improvement using fixer and temperature to reduce milkiness while Pennington and Harper of IBM explored silver grain sensitized DCG. IBM researchers, Fillmore and Tynan found agreement with Lin's earlier work on photo induced index modulation. Meyerhoffer did an independent study at RCA and more clearly defined the micro-structure. About 1973 the torch was passed to Hughes Research labs where Don Close, Andrejs Graube and Gaylord Moss began cooking up HUDs and publishing very thorough research on dye sensitized gels. McCauley put DCG on Plexiglas that year as well. Mike F. visited HRL and made his first DCG in '73. My first followed early in 1974 while working at Hughes Laser Division, Culver City, CA. In 1975 Kubota began publishing red sensitizing followed in 1976 by BJ Chang at ERIM on reprocessing. In 1977 much of this was put in an orange reference book published by Springer, the DCG author was Meyerhoffer. I was tutored by Andrejs Graube from time to time and he visited my first production lab (garage) in the south bay area in 1975. I wrote my first DCG paper in 1979 based on experience with manufacturing and information from Andy, who was the only one of the early researchers that I ever got to know as a close friend. He continued to work in the field and published through 1979 at least. I think I am the only worker in the field, that started before 1975, that still depends mostly on DCG for a living. Every one else graduated from class and moved on and I am still repeating Shankoffs original experiments with hardly any changes into the year 2000. In Russia, Uri Denisyuk invented the single beam reflection geometry way before DCG was discovered. Single beam geometries worked perfectly with DCG because of the easily adjusted absorption and a huge dynamic range. I probably should have been paying him royalties in the seventies because almost everything I made was shot single beam at Brewster's angle. When I finally met Uri, I was relieved to learn that he was not concerned about my popularizing his techniques. {| border="1" |- | [[File:RDRUri.jpg]] | [[File:RDRHarry.jpg]] |- | Uri Denisyuk at recent SPIE (trying to collect royalties) | Harry Knowles 1995 at Metrologic |} === Serendipity === Back to the story, I returned to Hughes with one of Mike's broken 8 x10 inch dichromates determined to produce my own, Mike was not about to share more of his tricks of the trade so I was on my own. I coated Knox unflavored gelatin "'''Jello'''" on glass plates in my apartment using a record player built into an old steamer trunk. The dichromate processes described in the literature by Shankoff, Lin and Chang were all too time consuming to suit me. Mike had suggested during a phone conversation that I mix in all the sensitizing dichromate before coating to save some time and that helped. Everything I made initially came out milky white until I accidentally dropped an exposed plate into Milton's hardening fixer prior to soaking it in water. It was only in the fixer for 30 seconds but that proved to be sufficient to harden it enough to take the shock of hot alcohol without precipitation. A short process was immediately at hand. From then on I could make coatings on any glass surface in 5 minutes, expose them in another 5 minutes, process them in another 5 minutes and seal them up in less than 5 minutes. I immediately produced a few boxes full for show and tell and then lit the lab on fire. I managed to keep that trick under my hat until 1982, when Fred Unterseher persuaded me to publish it. I inadvertently also sold it to Steve McGrew (Holosonics) in 1979 and thought he might make it public just as I was selling it to IBM, but he never did publish. What he did publish was a very fine paper on color control in DCG in 1980, one of the first papers useful to artists working in color at the time. My method of controlling the color and clarity of master holograms was not disclosed til 1985. I dropped a developed broadband hologram into a certain bath that was about 75% alcohol and when I retrieved it and dipped it in hot dry alcohol it came back as a low scatter blue hologram. From that day in Nov 1975 I had a fast, tunable way to make bright masters that added almost no noise to the copies and so I finally had all the processes I needed to start making masters and churning out thousands of bright "dichromates" for sale. Which is what I did. {| border="1" |- | [[File:RDRPendants.jpg]] | [[File:RDRSpike.jpg]] |- | Dichromates, 1977 collection | Spike Stewart designed the first eyeglasses, 1977 |} === Accidents that counted === The spring of 1974 saw the opening of the LA school of holography on the Santa Monica beach and I finally met Lloyd Cross and many of the other originals from the San Francisco school of holography. I learned what I could from them and swapped dichromates for multiplexes and rainbow holograms. Lloyd gave me a great copy of his "kiss" multiplex for a handful of dichromate gems and I promptly destroyed it in one of my alcohol fires, which also got me thrown out of my slightly charred apartment, which resulted in my subsequent marriage to my wife of 25 years, Ruth Caird, whose prior husband was my office mate at Hughes. My future at Hughes was compromised somewhat by two unplanned attempts to burn down building six while processing dichromates. The last thing I learned to make while still employed there were the dichromate Apothecary jars filled with coins and a watch works nested in each one. These items were picked up by Selwyn Lissack and sold in NYC. I made about 24 of them each week in my garage in Lawndale California. They were made with a 7 mw cadmium laser purchased from the same Harry Knowles that wrote the original hologram article that Mike found. I started every Saturday the same way, mix up and filter a quart of yellow Jello, coat and shoot and process, drink a little wine, and then try to glue the caps on them. {| border="1" |- | [[File:RDRJarbatch.jpg]] | [[File:RDRJarsall.jpg]] |- | Original experimental jars and glasses | Production of apothecary jars |} A little wine and beer caused a few more accidents, like the time I lost control behind a speedboat at about 85 mph and skittered across the water right up on shore losing my ski and the whole back of my pants. Another time I was flying a hang glider behind a boat on the Colorado river when I got too far out to one side and crashed, breaking up the glider and shredding my levis. Then there was the time I rode a bicycle into a reservoir ripping my foot open to the bone, Ruth took me in to get stitched in Fresno which led to getting hitched to her in LA. In between I almost lost my foot to a bone infection which was only discovered when I broke the same leg (sliding down a banister) at Dodger stadium. If I had not broken my leg the infection would have gone undetected long enough to require an amputation .It was as my foot healed that I had my only boiling acetone fire, the landlord asked me to move immediately so I asked Ruth to marry me and help keep me out of trouble and she did. I have never had another alcohol or acetone fire since then and have learned to keep the alcohol in the process tanks and not in me. {| border="1" |- | [[File:RDRGabor75.jpg]] | [[File:RDRJar.jpg]] |- | Dennis Gabor and wife next to Selwyn Lissack about 1975 | Selwyn says, "I made this dichromate jar just for you." |} === Leaving LA === In 1975 we moved to Utah to build Argon Lasers at American Laser and Selwyn asked me to make pendants for him. He put me into business single handedly but his early attempts to take credit for the production of the dichromates provided some truly hysterical moments at the SPIE San Diego conference of 1977. By that time I had been selling pendants to the Goldberg boys at Holex and had supplied a few other dealers on the west coast and the museum of holography in New York. Rosemary (Posy) Jackson, of the MOH, turned to me several times during the conference and mouthed out the phrase "I made those dichromates" causing major rib damage from laughter. My first production lab in Utah was in the basement of a house at 3488 E 7590 S, which is more or less at the mouth of Big Cottonwood Canyon and occasionally I would go skiing on a lunch break. We were 11 minutes from the lower chair lift at Snowbird. I can no longer remember who went with me but Jerry Heidt may have been one, we occasionally went cow trail motor cycling and skiing during all the years that he worked in three or four of my labs. Rick Lowe was my first employee and I think Jerry's brother was my second. Rick and I had motor boats and would take everyone to lake Powell for water skiing from time to time. At one time I had 8 to 10 people working in my basement. I never intended to manufacture in the mass production sense and tried farming out the production several times over ten years. It moved to Richland Washington once when patent issues were hot and Holosonics (Holotron) insisted on trying to cash in on what ever I was doing. In 1979 Lee Dickson came calling from IBM and we made a fine looking holographic scanner for him. I thought I finally had a good reason to want to manufacture something. The first day he visited, he needed a little evidence that we could actually make dichromates in the little suburban house we owned at the time so we took his watch and sat him on the couch upstairs while Rick Lowe and I went down and made a nice reflection hologram of his watch. It took about 15 minutes and then we brought it up and gave it to him, he seemed impressed. We quickly struck a tentative product development deal and moved the operation into a chicken coup in Draper while we built a brand new building just for the production of holographic scanners. IBM negotiators came out to firm up a technology buy while we were operating in the chicken coup and they came on one of those days when my cat had sneaked in and left a load on my desk. They were not impressed. We only asked for $50k to transfer the disc making technology but learned in later years that they were prepared to pay perhaps 10 times that much. Nevertheless, I thought it was a fair price and I found a good friend in Lee Dickson so it was all worthwhile. IBM pulled the plug after nearly two years of development and production. We helped set up a production line in North Carolina where they made their own discs for the next 7 years. We used the new building to make larger plates and pendants and pulse portraits and even took the company public in a lame sort of way. I figured out eventually that I am a sole proprietor type of entrepreneur. The lessons cost me a few friends and partners. {| border="1" |- | [[File:RDRScanners.jpg]] | [[File:RDRRdraust.jpg]] |- | Holographic Scanners for bar code reading and for printing, 1982 | RDR in Australia buying Boomerangs, 1987 |} === Laser Accidents === Mike and I had a great mutual interest in Lasers and struggled to own and build them as soon as they became available. I tried to make a dye laser from plans in Scientific American by Peter Sorokin. It was mostly built in 1971 and it nearly killed me at least once. I managed to get both index fingers across the flashlamp with the capacitor bank mostly charged. It discharged about 60 joules straight through my heart. I involuntarily threw the laser across the room into a wall and broke the lamp. Mike made an Argon laser and managed to violently blow the bulky Brewster windows off the ends with high Argon pressures. My best accident was while at Hughes developing a CO2 waveguide laser. The power supply was 10KV at 100ma dc and protected by a painfully slow mechanical breaker. I worked with one hand behind my back but I hardly ever turned off the power to make adjustments because all the surfaces I touched were insulated, or so it appeared. The insulation broke down Nov 23^rd 1974 and a kilo-watt of power flowed into my thumb and out of a circular patch on my belly, blowing a section of my shirt right into the air as the current found a ground in a metal cabinet. My legs extended and my arm struck my chest as I flew backward and upward onto a wall 4 or 5 feet behind me. It seemed as though I were looking down a tunnel from somewhere about 20 feet behind my body and I was partially paralyzed. I wrestled with paralysis for ten or twelve minutes and then felt pain along the track the current took for a few days. I got married 3 days later and was always glad that my belly was closer to the cabinet than was my zipper. The hole in my belly and shirt was the size of a dime and somewhat charred. I once had a Coherent cadmium laser that had a negative high voltage on each of the mirror mounts and it required frequent fine tuning. The voltage was only about 2Kv and it was possible to use two ball end drivers with plastic handles to do the work as long as you never slipped off the plastic. About the 10^th time re-tuning with this head cradled in my lap, I slipped and took the full voltage across my chest again and the poor laser flew across the room into a wall, breaking the tube. === Throwing in the towel === 1984 was my last year making pendants, I had failed as a business manager in multiple ways and made the decision to sell the company to the first interested party with a little cash. I sold it to the wrong group of guys and ended up paying out tens of thousands of dollars in subsequent years just to cover the debts they created for me. I moved to Paradise and started over from scratch, making nothing but holographic optical elements. The original Electric Umbrella went through numerous name changes and ownerships and evolved roughly into Krystal Holographics, now owned by Dupont. Jerry Heidt is the only remnant from the original basement operation. I imagine that if I had been a better manager and had resolved conflicts with Mike and Rick and Jack and Larry and Jerry and Scott and some backers and bankers and candlestick makers that I could have had a much more successful early venture in holography. I have learned those lessons and have determined that too much energy has to go into growing a successful business venture. During the year or so that I tried to capitalize and grow I missed the time in the lab, the study time, the new technologies to be learned. Those things get neglected when business interests dominate. I call myself a lab manager now and that is about the extent of the responsibility that I take on whenever I can get away with it. {| border="1" |- ! colspan="2" | (About 1982 or 1983) |- | [[File:RDRRick.jpg]] | [[File:RDRJack84.jpg]] | [[File:RDRJerry83.jpg]] |- | Rick Lowe, first employee, 1976 | Jack Worthington, partner | Jerry Heidt, 1980, still at it |} === Flying for relaxation === {| border="1" |- | [[File:RDR500inst2.jpg]] | [[File:RDRGt500rdr93.jpg]] |- | My GT-500 | A boy and his 7^th airplane |} I took up flying once again after moving to Paradise, this time I taught myself to fly ultralight aircraft rather than hang gliders. On one sunny late August afternoon I lifted off to chase water skiers at the local lake in a machine best described as a flying lawn chair. I swooped down on them from behind and above only to pull up sharply as I roared past like a big scary bumblebee. On the last pass I pulled up along side of a skier and while I looked at his startled expression and waved I let my front wheel dip into the water and with a loud slap I hit the water, broke off a wing and proceeded straight to the bottom, landing upside down in thick mud, 22 feet below the surface. It was dark when I regained my senses and I carefully unbuckled my seatbelt and worked my way past the flying wires which were laying in every direction. Then when I was free I tried to swim up but only buried my head in the mud. I had no air in my lungs to float up with so I took my white foam filled helicopter helmet off and held it by the communication cord and let it guide me to the surface. I gulped air just as my vision faded to black. I never experienced a moment of panic and would have died pleasantly in a few more seconds without oxygen. The lake ranger who had been chasing me all summer helped me haul the wreckage out of the water but would not stop laughing the whole way in to shore. I rarely fly that low across water any more and have since survived five more crash landings in various off airport locations. I flew right into a mountain with a passenger, then into a barbed wire fence, cracking a rib, I landed in a tree once and most recently flew into a 7.5 kV power line. It hurt a lot. Earlier that day I had buzzed Sharon McCormack and her boy friend at Hood River and had flown down into Mt St Helens volcano and over Mt Rainier so I was feeling invincible. A thunder storm and a moonless night conspired to keep me from seeing the ground. I hooked the power line with the nose wheel, stripped it off the pole and broke it before free falling into a hay field. My feet went right through the fiberglass shell and aluminum pedals and 6 inches into the dirt. === Outside ventures === Fred and I taught a crew in England (Raven) how to make dichromates and they did a great job of it but could never make enough money to stay in business. I taught a group in Kansas (Portson) once how to do it and they did a good job but had trouble staying in business also. I helped out Paula Dawson for a trip to Australia and some change in 1987 and I taught a lot of people at the annual school at Lake Forest College but none of them have made businesses that I know of. Dichromates have largely been replaced with cheaper mass produced photopolymer holograms. The medium still works best for high performance diffractive optics and probably will for a long time to come. Bright, clean DCG masters are still made for copying into photo-polymers. I joined Lee Dickson and two other x IBM engineers in a venture called Holoscan a few years ago and we bought back all the Scanner making technology from IBM. We made some product and then sold the company to Harry Knowles, still the owner and CEO of Metrologic instruments. I became the teacher and taught Harry and his crew how to make dichromated gelatin holograms some 25 years after he taught Mike and I how to make our first holograms. Harry is a really great guy and he runs the only production line I know of today that makes bar code scanners on glass plates using dichromated gelatin. He also sent me a lot of Habanero pepper sauces for Christmas this year, he is very thoughtful (thanks to his wife). I also taught technicians and engineers at APA, Northrop, Process Instruments, Terrasun and Terrabeam and a few other places how to cook yellow Jello. I also teamed up with a group in Seattle (Virtual I/O) about 1990 and we designed and manufactured head mounted displays (HMDs) for a few years. Eventually the major stockholders discovered we were selling them for less than the cost to manufacture them and they pulled the plug. You can still buy the HMD sets but they cost a lot more now and I don't own any part of the new company. I am still actively involved in a Laser Com business in the Seattle area and have assisted in setting up a production line for Large area holoscope receivers but don't plan to move there any time soon. My lab has been supported through the 90s with several NASA contracts to make ever larger LIDAR scanners. We are currently doing our best to put out dichromated gelatin HOEs that measure nearly a meter in diameter. These HOEs are being made to conically scan the skies at multiple wavelengths and to have a field of view of only a hundred micro-radians. These are by far the most challenging projects of my career, and therefore the most fun. We have been making HOES of 400 mm diameter for ten years but the year 2000 will be the year of our first meter size optics for use in the near UV region. We have also been making a lot more gratings for spectrographs in the past few years, and the pace appears to be picking up along with the size and the price. I imagine that the business opportunity is now better for me than it ever was before. It is a bit of a shame because I have no desire to even try to grow a business and also don't know anyone else that does. I really enjoy assisting other businesses to make products and plan to just keep on doing that for work and play. I have 4 full time lab jocks and a grad student to keep busy and we are learning how to polish glass and how to operate high vacuum etchers and coaters in a new and larger lab. {| border="1" |- | [[File:RDRLab99.jpg]] | [[File:RDRNasa.jpg]] |- | Lab addition in 1998, another 4000 sq ft | LIDAR scanner for NASA |} === Significant Inventions === I have a few patents but they don't cover any of my real inventions. My first invention was a semi automatic jerky chopper and I built it when I was 18 years old. It cost about $90 to build from a furnace blower, a lawn mower and a few metal parts and was used commercially for over ten years. My next invention was a glue mixer. It cost $4.00 in parts and was made from a motorized stage light fixture and a plastic kitchen cup. It mixes glue in paper cups like a concrete mixer and generates no bubbles. Next I invented the first dynamic spatial filter. It consisted of a curved first surface mirror glued to a speaker cone and the speaker was driven by a hard rock radio station. It only worked well for contact copies using a single beam but it did work, and it cost about $10. I made a few odd fringe lockers but would never claim them as an invention. For Pilkington in 1982 I invented the hand held air gate method of making reflective head up displays and several years later another company (Flight Dynamics) patented it. I thought it was too trivial and obvious to ever get patented, but then many of us had to work under the infamous "claim 6", so nothing else that gets patented could ever be a surprise. Most recently I think I invented the "aperture scanner". It enables me to make big clean recordings with little lasers and consists of a rotating tilted window. {| border="1" |- | [[File:RDRPosyoffice76.jpg]] | [[File:RDRRandr.jpg]] |- | Rosemary (Posy) Jackson about, 1976. Quote from SPIE, 1977 "Psst!, I made those Dichromates!" | RDR and wife Ruth, recent SPIE meeting.<br> Mom and Pop running the business. |} == DCG References == See: [[DCG References]] [[Category:Rallison]] [[Category:DCG]] e021fcdcfd747b2bdbb134eb616806d5c1c6a875 0 830 1703 1702 2013-05-12T04:08:08Z Jsfisher 1 1 revision wikitext text/x-wiki <h3>Early researchers (to 1974)</h3> <ul> <li>T. A. Shankoff, "Phase holograms in dichromated gelatin" <em>Appl. Opt.</em> <strong>7:</strong>2101-2105, 1968 </li><li>T A Shankoff and R K Curran "Efficient, high resolution, phase gratings", <em>App Physics Letters</em> 13:pp239-241, 1968 </li><li>L.H. Lin, "Hologram Formation in Hardened Dichromated Gelatin Films." il <em>Ap Optics</em> 8:963-6 My, 1969 </li><li>H. Kogelnik, "Coupled wave theory for thick hologram gratings" <em>Bell Syst Tech J. </em> <strong>48</strong>:2909-2947, 1969 </li><li>R.G. Brandes and others, "Preparation of Dichromated Gelatin Films for Holography." <em>Ap Optics</em> 8:2346-8 N, 1969 </li><li>R.K. Curran and T.A. Shankoff, "Mechanism of Hologram Formation in Dichromated Gelatin." <em>Ap Optics</em> 9:1651-7 Jl, 1970 </li><li>T.P. Sosnowski and H. Kogelnik, "Ultraviolet Hologram Recording in Dichromated Gelatin." <em>Ap Optics</em> 9:2186-7 S, 1970 </li><li>M. Chang and N. George, "Holographic Dielectric Grating; Theory and Practice" <em>Ap Optics</em><strong> 9</strong>:713-719, March 1970 </li><li>L.H. Lin, "Method of Characterizing Hologram-Recording Materials." <em>Opt Soc Am J.</em> 61:203-8 F ,1971 </li><li>Milton Chang, "Dichromated Gelatin of improved optical quality", <em>App Optics</em>, 10 : p2550-2551, Nov 1971 </li><li>D. Meyerhofer, "Spatial Resolution of Relief Holograms in Dichromated Gelatin." <em>App Optics</em> 10:416-21 F, 1971 </li><li>Gary Fillmore, Richard Tynan, "Sensitometric characteristics of hardened dichromated gelatin films" <em>J of Op Soc,</em> 61:pp199-202, 1971 </li><li>K S Pennington, J S Harper, "New photo technology suitable for recording phase holograms and similar information in hardened gelatin", <em>App Phys Lett </em>18: pp80-84, 1971 </li><li>W. S. Colburn, "Holographic Optical Elements", <em>Technical Report, contract F33615-72-C-1156</em>, 1973 </li><li>F. T. S. Yu. "Effect of Emulsion Thickness Variations on Wavefront Reconstruction". <em>App Optics</em><strong> 10</strong>:1324-1328 June 1971 </li><li>D. Meyerhofer, "Phase Holograms in Dichromated Gelatin.". <em>RCA R.</em> 33:110-030 Mr, 1972 </li><li> D. H. Close, A. Graube, "Materials for Holographic Optical Elements", <em>Technical Report AFML-TR-73-267</em>, Oct. 1973. </li><li>A. Graube, "Holograms recorded with red light in Dye sensitized dichromated gelatin", Optics Comm.8:251-253 </li><li>D G McCauley, "Holographic Optical Element for visual display applications", App Optics, 12: 232-241, 1973 </li><li>D.H.Close, A. Graube, "Holographic Lens For Pilot's head up display", <em>Techmical report, contract# N62269-73-C-0388</em>, 1974 </li><li>R D Rallison, "DCG applied with a record player and broadband processed in 2 minutes" <em>Hughes Aircraft</em>, Jan 1974 (never published, just bragged a lot) </li></ul> <h3>Additional selected DCG related publications (to 1996)</h3> <ul> <li>S. K. Case. "Coupled Wave Theory for Multiple Exposed Thick Holographic Gratings".<em> Opt Soc Am J.</em> 65: 724-9 Je, 1975 </li><li>A.Alferness, S.K. Case, "Coupling in Doubly Exposed, Thick Holographic Gratings" <em>Opt Soc Am J.</em>65:730-9 Je 1975 </li><li>R.V. Pole and H.P. Wollenmann, "Holographic Laser Beam Deflector". <em>App Optics</em> 14:976-80 Ap 1975 </li><li>S. K. Case, "Multiple exposure holography in Volume Materials", <em>Doctoral Dissertation</em>, U of Michigan, 1976 </li><li> B.J. Chang, "Post Processing of Developed Dichromated Gelatin Holograms", <em>Optics Communications</em>, <strong>17</strong> (3): 270-271, June 1976. </li><li>T. Kubota, T. Ose, M. Sasake and K. Honda "Hologram Formation with Red Light in Methylene Blue Sensitized Dichromated Gelatin" <em>Applied Optics,</em> <strong>15</strong>(2):556-558, Feb. 1976. </li><li>W. S. Colburn &amp; B. J. Chang "Holographic Combiner for Head-Up Displays", <em>Technical Report AFAL-TR-77-110</em> , Jan 1977 </li><li>H. M. Smith, <em>Holographic Recording Materials,</em> Springer Verlag, 1977 </li><li>A. Graube, "Dye Sensitized dichromated gelatin for holographic optical element fabrication" Photographic Sci and Eng, 22: pp37-41, 1978 </li><li>A. Graube, "Holographic optical element materials research", <em>Technical report, Air Force contract # F44620-76-C-0064,</em> 1978 </li><li>S.K. Case and W.J. Dallas, "Volume Holograms Constructed from Computer Generated Masks." <em>App Opt</em> 17:2537-40 Ag 15, 1978 </li><li>R D Rallison, "Fabrication of a holographic scanning disc" <em>Technical report to IBM</em>, Raleigh NC, 1979 </li><li>R D Rallison, "Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)."<em>SPIE Proceedings</em> 212:22, 1979 </li><li>B.J. Chang and C. D. Leonard, "Dichromated Gelatin for the Fabrication of Holographic Optical Elements", <em>App Opt</em> 18:2407-17 Jl 15, 1979 </li><li>S.P. McGrew, "Color Control in Dichromated Gelatin Reflection Holograms", <em>Proc. SPIE </em><strong> 215</strong>:24-31, 1980. </li><li>B.J. Chang, " Dichromated Gelatin Holograms and Their Applications". <em>Opt Eng</em> 19:642-8 S/O, 1980 </li><li>W.R. Graver et al, "Phase Holograms Formed by Silver Halide Sensitized Gelatin Processing" <em>App Opt</em> 19:1529-36 My 1, 1980 </li><li>S.K. Case et al, "Multi facet Holographic Optical Elements for Wave Front Transformations". <em>App Opt</em> 20:2670-5 Ag 1 1981 </li><li>Sven Sjolinder, "Dichromated Gelatin and the Mechanism of hologram formation", <em>Photo Sci and Eng</em>, 25: pp 112-117, 1981 </li><li>D. A.Winick, "Thick Phase Holograms", Environmental Research institute of Michigan, Level, January 1981 </li><li>L. Solymar &amp; D.J. Cooke , <em>Volume Holography and Volume Gratings</em>, Academic Press, 1981. </li><li>J. Oliva et al, "Diffuse-Object Holograms in Dichromated Gelatin." <em>App Opt </em>21:2891-3 Ag 15, 1982 </li><li>H. Bartelt, S.K. Case, "High-Efficiency Hybrid Computer-Generated Holograms." <em>Appl Opt</em> 21:2886-90 Ag 15,1982 </li><li>R D Rallison, "Hologram Scanner Design and Fabrication in Dichromated Gelatin (DCG)." Proc SPIE, August, 1982 </li><li>R D Rallison, "Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College </li><li>First International Symposium on Display Holography, July 1982 </li><li>L.D. Dickson, "Holography in the IBM 3687 Supermarket Scanner", <em>IBM J. Res &amp; Devel</em> 26:228-34 Mr 1982 </li><li>.J.E. Ludman, "Approximate Bandwidth and Diffraction Efficiency in Thick Holograms." <em>Am J. Physis</em> 50:244-6 Mr.1982 </li><li>Tung H. Jeong, <em>Proceedings of the International Symposium on display holography,</em> Vol I 1983 </li><li>Y.-Z Liang, "Multifocus Dichromated Gelatin Hololens". <em>Appl Opt </em>22:3451-6 N 1 1983 </li><li>A. Fimia, "Noise Reduction in Holographic Images Reconstructed with Blue Light". <em>Appl Opt</em> 22:3318 N. 1, 1983 </li><li>J. Oliva et al, "Dichromated Gelatin Holograms Derived from Agfa 8E75 HD Plates" <em>Appl Opt</em> 23:196-7 Ja 15 1984 </li><li>R D Rallison, "Characteristics of Dichromated Gelatin (DCG) Scanners for Printing Applications"<em>Proc. SPIE</em>. 498: 199, 1984 </li><li>R D Rallison,"Applications of Holographic Optical Elements" Lasers and Applications,pp61-64 December 1984, </li><li>S. Calixto and R.A. Lessard, "Real-Time Holography with Undeveloped Dichromated Gelatin Films" <em>Appl Opt</em> 23:1989-94 Je 15, 1984 </li><li>Ryszard Gajewski "Holographic Technology for Solar Energy Concentration" <em>Technical Report No. 87-1479</em>, 1984. </li><li>C. Solano, Lessard et al, "Red Sensitivity of Dichromated Gelatin Films".<em>Appl Opt</em> 24:1189-92 Ap 15 1985 </li><li>J. C. Newell et al, "Holograms in Dichromated Gelatin: Real-Time Effects" <em>Appl Opt </em>24:4460-6 D 15 1985 </li><li>Jose R. Margarinos &amp;Daniel J Coleman "Holographic Mirrors" <em>Proc. SPIE </em> <strong>523</strong>:203-218, 1985. </li><li>C. Solano and R.A. Lessard, "Phase Gratings Formed by Induced Anisotropy in Dyed Gelatin Plates" <em>Appl Opt</em> 24:1776-9 Je 15 1985 </li><li>Richard D. Rallison, "Holographic Optical Elements (HOES) in Dichromated Gelatin (DCG)", <em>Proc. SPIE</em> <strong> 523</strong>:292-295 (1985). </li><li>S. Calixto et al "Real-Time Optical Image Processing and Polarization Holography with Dyed Gelatin". <em>Appl Opt</em> 24:2941-7 S 15 1985 </li><li>Tung H. Jeong, P<em>roceedings of the International Symposium on display holography</em> Vol II 1986 </li><li>T. Kubota, "Recording of High Quality Color Holograms"<em> Appl Opt</em> 25:4141-5 N 15 1986 </li><li>P. Hariharan, "Silver Halide Sensitized Gelatin Holograms: Mechanism of Hologram Formation." <em>Appl Opt</em> 25:2040-2 Jl 1, 1986 </li><li>R. Changkakoti and S.V. Pappu, "Study on the pH Dependence of Diffraction Efficiency of Phase Holograms in Dye Sensitized Dichromated Gelatin." <em>Appl Opt</em> 25:798-801 Mr 1 1986 </li><li>C. Solano et al Methylene Blue Sensitized Gelatin as a Photosensitive Medium for Conventional and Polarizing Holography" <em>Appl Opt</em> 26:1989-97 My 15 1987 </li><li>Daniel K. Angell, "Improved diffraction efficiency of silver halide (sensitized) gelatin", <em>Appl Opt</em>, 26:4692-4701,1987 </li><li>R D Rallison,"Holographic Scanners for Machine Vision, Printing, and Bar Code Applications." Proc. SPIE 747:pp 1987 </li><li>H K Liu, "Simplified dichromated gelatin hologram recording process", <em>App Optics</em>, 26:372-376, 1987 </li><li>D.J. Jacobs and M. G. Marsland, "Reduction of Sensitizer Concentration Gradients in Dichromated Gelatin Films"<em> J Phys E</em>. 20:899-901 Jl 1987 </li><li>R. D. Rallison, "Materials for Volume Phase Holographic Notch Filters" <em>SBIR #A 86-68 Final Report</em>, U.S. Army CECOM, Ft. Monmouth, N.J. Aug.1987 </li><li>Jon D. Masso "Multilayer Thin Film Simulation of Volume Holograms" <em>Proc. SPIE</em> <strong>883</strong>:68-72, 1988 </li><li>R D Rallison, "Cascaded Transmission Holograms for Head-Up Displays". <em>Proc. SPIE</em> 883: pp 1988 </li><li>N. Capolla and R.A. Lessard, "Processing of Holograms Recorded in Methylene Blue Sensitized Gelatin" <em>Appl Opt</em> 27:3008-12 Jl 15, 1988 </li><li>R. D. Rallison "Incoherent Multifocus Hololens design and fabrication", <em>Proc. SPIE </em><strong>1183</strong>:663-668 1989 </li><li> R. D. Rallison "Survey of properties of volume holographic materials", <em>Proc. SPIE</em> <strong>1051</strong>:68-75 1989 </li><li>James M Tedesco, "Holographic laser -protective filters and eye-wear" Opt Eng 28:p609-615, 1989 </li><li>Y. Amitai et al "Holographic Elements with High Efficiency and Low Aberrations for Helmet Displays", <em>Appl Opt</em> <strong>28</strong>:3405-3416 Aug 15 1989 </li><li>J. L. Salter and M. F. Loeffler, "Comparison of dichromated gelatin and Dupont HRF-700 photopolymer as media for holographic notch filters" <em>Proc. SPIE </em> <strong>1555</strong>:268-278 (July 1991) </li><li>Chris Rich, David Cook, "Lippman volume holographic filters for Rayleigh Line rejection in Raman Spectroscopy", Proc. SPIE 1461:2-7, 1991 </li><li>R. D. Rallison, "Control of DCG and non silver holographic materials" <em>Proc. SPIE </em> <strong>1600</strong>: 26-37 1991. </li><li>R D Rallison,"Polarization properties of gelatin holograms" <em>Proc</em><em>. SPIE</em> 1667:pp 1992. </li><li>R D Rallison, "Using Thick DCG, 30 to 100 microns" Proc. SPIE 1914:pp 1993. </li><li>L D Dickson, R D Rallison et al, "Holographic polarization-separation elements" <em>Appl Opt</em>. 33:5378-5385, 1994 </li><li>R. D. Rallison and S. R. Schicker, "Wavelength compensation by time reverse ray tracing", <em>Proc. SPIE </em><strong>2404</strong>: 217-225 1995 </li><li>Hans Dieter Tholl, "Polarization properties of volume phase gratings", <em>Optical Engineering</em>, <strong>34</strong>(10)2879-2885 Oct 1995 </li><li>Hans I Bjelkhagen, <em>Holographic Recording Materials</em>, SPIE publications, 1996. </li><li>R D Rallison, Steve Arnold, "Wavelength compensation at 1.064 microns using hybrid optics" Proc SPIE 2689, 1996 </li></ul> [[Category:Rallison]] 003a50c2e3a186a7726a6a7ecc4fc13773424154 0 831 1705 1704 2013-05-12T04:08:08Z Jsfisher 1 1 revision wikitext text/x-wiki Also see a sample of [[Equatoins|common DOE surfaces]]. *Complete Spectrograph designs and brassboard prototypes, diffractive component production for the same *Transmission gratings from 10 to 4000 l/mm, plane, slanted, crossed, cophasal, multiplexed spatially or stacked in volume from spectroscopic instrument to light show quality, in DCG, photopolymer, resist or plastic replicas. *Powered transmission HOEs of f/2 or greater with low aberrations, apertures to 1 meter and wavelengths from 355 to 1064 nm, for LIDAR applications. *Off axis Multifocus hololens and flys eye arrays, optical interconnects and general multiplexed powered optics. ==== "Catadioptric HMD" ==== {| |- |[[Image:cathyb1.gif|center]] | *Narrow Notch filters from 400 to 900 nm, 10 to 40 nm bandwidth, Optical densities to 5 or 6 in 30 microns of DCG. *[[Directional diffusers]], dipixelators and homogenizers in virtually any configuration, (design, fabrication, and production). *HUD and HMD components including conformal multiwavelength combiners on CR 39 or glass of any radius. *TIR gratings for photon buckets, edge lighting, polarizing. |} ==== "Transmissive Grating Spectrograph" ==== {| |- |[[Image:graph3.gif|center]] | *Bidiffringent polarization separator that works in a Wollaston configuration and broadband planer polarization splitters. *Complete ZEMAX optical designs including binary surfaces, masks and phase only replicas in volume or surface media. *Hybrid refractive/diffractive design and fabrication. |} ==== "Powered Laser Scanner" ==== {| |- |[[Image:graph4.gif|center]] | *In-house lithographic photoreduction for some DOE production. *Conversion of customer generated amplitude masks to efficient phase DOEs and HOEs. *IR gratings for 3 to 12 microns in slumped amorphous IR glasses. *Addition of high frequency carriers to low angle CGHs. |} '''The odds are in your favor, that we can make the HOE you need.''' == Advantages of DOEs == #Simultaneous performance of several functions such as [[Equations#Holographic Deflectors (hologons)|deflection]], focusing, filtering, and collimating as in bar code scanners. #Parallel performance of similar or different functions such as the multifocus Hololens array for parallel pattern recognition. #Ease of stacking elements such as multi-wavelength solar reflectors. #The formation of optics on curved substrates such as heads up displays on visors or curved windshields. #Weight and volume of a holographic system is likely to be less than refractive optics, especially for large apertures. #Ease of replication makes production fast, inexpensive and relatively simple. '''''Last modified on 9/16/97''''' [[Category:Rallison]] c1a10806b51f7ee8cc5fd50429581a66292b1233 0 270 1707 388 2013-05-12T04:08:09Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:CIEDiagram.jpg]] Holograms need a material to record interference fringes. There are many materials that can record fringes. '''[[Silver Halide Chemistry]].''' Theory and Practice of Making Silver Halide Plates and Development. '''[[Silver Film Comparison Chart]]''' A quick comparison of the qualities of different commercially made films. '''[[Dichromated Gelatin Chemistry]].''' Theory and Practice of DCG Plates and Development. '''[[Polymer Film and Processes]]'''. Many commercially sold holograms are made from photopolymers. '''[[Photoresist]]'''. Taken from the electronics industry, this material can make relief holograms for embossing. '''[[Coating Methods]]'''. Coating Gelatin on to a glass plate is an art in itself. '''[[Crystals]]'''. There are many crystals that can record an image. The cost and exposure energy required is very high so they are not often used for holography. '''[[Embossed Holograms]]'''. These are like the holograms seen on credit cards. '''[[Gelatin]]'''. Used as the suspension medium to hold light sensitive particles. [http://en.wikipedia.org/wiki/Hologram#Materials Wikipedia's summary of Holographic Recording Materials] [http://en.wikipedia.org/wiki/Periodic_table_%28standard%29 Periodic Chart of the Elements] '''[[Books]]''' 155e35968057a437052d49b3dc62bd4bc0c9f685 0 271 1709 390 2013-05-12T04:08:09Z Jsfisher 1 1 revision wikitext text/x-wiki See [[Setups]] for more information on making these types of holograms. ===A Hologram Defined=== hol·o·gram (hŏl'ə-grăm', hō'lə-) n. A [[Diffraction|Diffraction Pattern]] which, when properly lit, produces a three-dimensional image. Typically, holograms are made using a laser as a light source and and a very high resolution film or glass plate to record the diffraction pattern resulting from interference between light coming directly from the laser and light reflected from the object. ===Transmission hologram=== This was the one of the first holograms made. A transmission hologram is made when the reference beam and light from the object enter the recording material from the same side. The recorded interference fringes form a transmission grating which diffracts light passing through the hologram. Properties include: * looks like a blurry rainbow image when viewed with white light * viewable as a sharp image only by shining laser light through the hologram * recording material requirements are more relaxed (less resolving power is needed) * simple set-up * greater depth of the scene is possible * the scene can be projected by shining a collimated laser beam through the hologram ===Reflection hologram=== A reflection hologram is made when the reference beam and light from the object enter the recording material from opposite sides. Properties include: * viewable in regular light * very simple Denisyuk style setup can be used * finished hologram is monochromatic (a single color) for each laser color used * color can be shifted by pre or post shrink/expanding recording material ===H1 to H2 copies=== H1 refers to a first generation (master) hologram. H2 refers to a copy made from the H1. H1s are usually transmission holograms and H2s are usually reflection. They may use different recording materials. Properties include: * Somewhat complex setup requirements * Objects can be made to appear to be coming out of the plate towards the observer * Once a usable master H1 is made and the setup constructed, many copies can be produced easily ===Rainbow Holograms=== Rainbow holograms are transmission holograms which are produced in such a way as to be viewable in regular white light. Depending on the viewing angle, the color changes (hence the term rainbow) Properties include: * perspective information is lost in one axis (for example, you may not be able see a change in perspective when looking from above or below) ===Open-Aperture Transmission Hologram=== An open-aperture transmission hologram is simply a transmission hologram the has the image very close to the film plane and is designed to be viewed in white light. Properties include: *White light viewable. *Image blurs colors as the image move in front of, or behind the film plain. *2 cm usable depth of field. *The image is achromatic. ===Multiplexed holograms=== Multiplexed holograms store many different holograms on one piece of film usually as multiple exposures. Properties include: * simple animations are possible * diminishing quality as more holograms are stored ===Edge Lit Holograms=== Edge Lit Holograms have the reference beam entering the plate from one edge instead of one face. This allows the illumination to remain hidden from the observer and makes for a fairly compact display. *They are difficult to make. [http://www.media.mit.edu/spi/SPIPapers/ryder/thesis.pdf Edgelit holography:Extending Size and Color] by Ryder Sean Nesbitt ===Embossed Holograms=== Embossed holograms are made by forming a rainbow transmission hologram in thermoplastic and bonding it to a mylar mirror. It is the kind of hologram seen on credit cards. Properties include: * very low per-unit cost when mass-produced * shallow hologram depth (usually just a few millimeters) * durable and flexible * mass production can use existing equipment and technology (e.g. CD production) ===Pulsed Holograms=== Pulsed Holograms can be either transmission or reflection. The key difference is the pulsed laser emits a short, powerful pulse of light rather than a continuous beam. This pulse (about 20ns) is short enough to stop moving objects and make an image. Even bullets can be stopped with the correct setup. Most often used for portraits. * The flash photography of holography * Stability requirements are greatly diminished, allowing for holograms of people, melting ice, flowers, animals, etc. to be made * Pulse lasers are very expensive * Setup and testing can be tricky and dangerous See [[Tips for Pulsed Ruby Holograms]]. ===True Color Holograms=== [[Image:CIEDiagram.jpg]] True color holograms are a variety of reflection hologram made with more than one laser color. There have been good true-color holograms made with two, three and four colors of lasers. The resulting hologram displays the same colors as the original object. * Since true color holograms are multiplexed holograms, recording material need to be capable of holding a lot of information * Lasers and equipment can be expensive and tricky to set up [http://www.ultimate-holography.com/GB/galerieanglais2Color.html See examples by Yves Gentet] 85b7157da9bc9b9b9a1d66f8a1beed793daef9dd 0 274 1711 396 2013-05-12T04:08:09Z Jsfisher 1 1 revision wikitext text/x-wiki Please add any links you have found useful. Try to alphabatize by Site title. '''[[Books]]''' can be found [[Books|here]]. ===Links to Holography Instruction=== *[http://home.comcast.net/~gakall/holopg/ Amateur Holography] Simple & Low Budget *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.nobel.se/physics/laureates/1971/gabor-lecture.pdf Dennis Gabor's Nobel Lecture, December 11, 1971] *[http://www.holographer.org The Holographer] *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] *[http://amasci.com/amateur/hand1.html Hand Drawn Holograms] *[http://www.holoworld.com/holoportraits/index.html Hand Made Hologram Portraits] An Amateur/Hobbyist Guide *[http://www.holostudios.com/holohelper/index.html Hologram Basic Principles] by Jason Sapan *[http://www.holokits.com/newsarticles.htm Integraf's Articles] *[http://www.focalimage.com/public/kaveh-PhD.pdf Kaveh's Thesis] *[http://www.buildcoolstuff.com/gallery/holograms.html Laser Pointer Holograms] *[http://www.repairfaq.org/sam/lasersam.htm Laser Sam's FAQ] The best source of laser related information on the net. *[http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html MIT Spring 2002 Holography course] *[http://www.holo.com/holo/book/book.html Practical Holography] by Christopher Outwater & Van Hamersveld *[http://www.holography.ru/techeng.htm Russion Holography 25 Holography Lessons] *[http://www.dragonseye.com/blog/categories/2-Tutorials Holography Tutorials] by Michael Harrison *[http://www.physics.ohio-state.edu/~kagan/holography/index.html Holography course at Ohio State] *[http://teched.vt.edu/gcc/CurriculumMaterials/HoloProject/HTML/index.html Virtual Holography course at Virginia Tech] *[http://www.ph.ed.ac.uk/~wjh/teaching/mo/holography.html University of Edinburgh] *[http://www.3dimagery.com Nuts to bolts online descriptions for hobbyist] *[http://geola.lt/download/synfography_virtual_scene_setup.pdf Synfography basics - virtual scene setup for Geola's colour holographic printing] ===Links to Holography Supplies and Tools=== ====Turnkey Equipment==== *[http://www.myholostudio.com/ Analogue holography] {Complete holography studios} *[http://geola.lt/show.php?lang=eng&cont=holo_index&lside=holo_index_left Digital holographic printing - Synfography] {Complete digital solutions} ====Electronics==== *[http://www.digikey.com DigiKey] {Electronics} *[http://www.goldmine-elec.com Gold Mine Electronics] *[http://www.allelectronics.com/ All Electronics] {Electronics} *[http://www.alltronics.com Alltronics] {Electronics} *[http://www.oatleyelectronics.com/ Oatley Electronics] {Electronics} *[http://www.mouser.com/Mouser Mouser] {Electronics} ====Film and Chemistry==== *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.laserreflections.com Laser Reflections] {Film} *[http://www.slavich.com Slavich] {Film, Plates and Chemistry} *[http://www.geola.lt/eshop/index.htm Geola] {Certified Slavich film and plates made for Geola distribution network, Chemistry} *[http://www.forthdimension.net Forth Dimension] {Film and Supplies} *[http://www.photoformulary.com Photographer's Formulary] {Chemistry} *[http://www.sigmaaldrich.com/ Sigma Aldrich] {Chemicals} *[http://perso.wanadoo.fr/holographie/GB/index.html Ultimate Film] {Film} *[http://www.abra-electronics.com Abra Electronics] {Isopropyl Alcohol} *[http://www.colourholographic.com Colour Holographics] {BB Plates - Red, Green, Blue, Pan} *[http://www.filmotec.de/Produkte/produkte.html Filmotec] {ORWO - Red, Green, Pan in works} *[http://www.fujihunt.com/fuji/fhweb2004.nsf/pagesbykey/Holo%20products?OpenDocument Fuji] {Pan said to be discontinued} ====Kits==== *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.geola.lt/show.php?lang=eng&cont=phot_en_kit&lside=phot_index_left Geola] {Holography supply refill kit} ====Lasers, Parts and Supplies==== *[http://www.optima-optics.com Optima] {Laser Diode Parts} *[http://www.nvginc.com NVG Inc.] {Laser Diode Parts} *[http://www.mi-lasers.com/index1.html Meredith Instruments] {Used Gas Lasers} *[http://www.roithner-laser.com/ Roithner] {Lasers and diodes} *[http://www.cnilaser.com/ CNI Laser] {DPSS Lasers}] *[http://www.lasersurplus.com/ Laser Surplus Sales] {Used Lasers} *[http://www.innolas.co.uk/ Innovative Laser Technology] {Lasers and parts} *[http://www.geola.com/ Geola] {High energy pulsed lasers, Holographic studios} ====Optics and Table Supplies==== *[http://www.thorlabs.com Thor Labs] {Optics} *[http://www.edmundoptics.com/us/onlinecatalog/browse.cfm Edmund Optics] {Optics} *[http://www.imagesco.com ImagesCo] {Supplies and inexpensive optics} *[http://www.surplusshed.com Surplus Shed] {Surplus Optics} *[http://www.murni.com/kit_0.htm Coulter Telescopes] {Inexpensive Collimating Mirrors} *[http://www.abrisa.com/index.asp Abrisa] {Glass Products, Dichroic Mirrors} *[http://www.lenoxlaser.com/ Lenox Laser] {Piinholes} *[http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=5646 Harbor Freight] {Magnetic Bases} *[http://www.use-enco.com/CGI/INSRIT?PMAKA=625-0300&PMPXNO=946102&PARTPG=INLMK3 ENCO] {Magnetic Bases} *[http://www.geola.com/ Geola] {Optics for pulsed holography} ====Robotics==== *[http://www.solarbotics.com SolarBotics] {Robot Technology} ====Surplus and Other Stuff==== *[http://www.sciplus.com American Science Surplus] {Surplus Parts and Cool Stuff} *[http://www.spsenergy.com/index.htm SPS Energy] {Solar Cells as Light Meter Probes} *[http://www.fgsi.com/oracal.htm Oracal] {instead of black paint for reflection holos #651} ====Tooling and Machining==== *[http://www.reidtool.com Reid Tool] {Tooling supplies} *[http://www.mscindustrial.com MSC Industrial] {Raw Metal and Machining Supplies} *[http://www.mcmaster.com McMaster Carr] {Raw Metal and Machining Supplies} ====Tools==== *[http://www.use-enco.com Enco] {Tools} ====Technical==== *[http://www.moshier.net/rtd-readme.html Thermistor calibration] ===Links to Amateur/Individual Holographers=== *[http://www.techsoft.no/holography/ronny_anderassen.htm Ronnie Anderassen] *[http://www.anait.com/ Anait] *[http://members.shaw.ca/holopix/My_holograms.html TomB] *[http://www.holography.demon.co.uk/ Margaret Benyon] *[http://rudieberkhout.home.mindspring.com/ Rudie Berkhout] *[http://cabd0.tripod.com/holograms/ Jeff Blyth] *[http://universal-hologram.com/index.htm Greg Cherry] *[http://web.mit.edu/museum/lightforest/lightforest.html Betsy Connors] *[http://www.holoworld.com/ Frank Defreitas] *[http://www.jfairstein.com/holoindex.html Jon Fairstein] *[http://www.hologramm.ch.vu/ Floh] *[http://webhome.idirect.com/~hgdesign Howard Gerry] *[http://www.ghisays.net Andres Ghisays] *[http://universal-hologram.com/nini%20gorglione.htm Nancy Gorglione] *[http://www.dragonseye.com/blog Michael Harrison] *[http://www.techsoft.no/holography Vidar Hegdal] *[http://www.pearljohn.co.uk/ Pearl John] [http://pearljohn.blogspot.com/ her Blog] *[http://www.bobdbob.com/~protius Tommy Johnson] *[http://www.designerinlight.com Colin Kaminski] *[http://www.holocenter.or.kr/ Juyong Lee] *[http://www.lucente.biz/index.html Mark Lucente] *[http://www.indimensionn.com/page3.html Bill McGarvin] *[http://www.holography.nl/ Kris Meerlo] *[http://www.rotorwave.com/holography.htm Ron Michael] *[http://www.3dimagery.com Steve Michael] *[http://holographics.com.au/ Martina Mrongovius] *[http://www.lasart.com/ August Muth] *[http://www.hololab.com/ Ikuo Nakamura] *[http://www.anamarianicholson.com/ Ana Maria Nicholson] *[http://www.holograms3d.com/ John Pecora] *[http://www.apepper.com/ Andrew Pepper] *[http://www.alchemists.com/visual_alchemy/holography.html Al Razutis] *[http://www.vilamedia.com/gallery.html Doris Vila] *[http://wengam.com/ Wenyon & Gamble] *[http://perso.wanadoo.fr/redlum.xohp/argonlaser.html W's Laser Projects Page] *[http://www.martymouse.net/happyfeet/ Danny Bruza (Danny Bee)] ===Links to Holograms For Sale=== *[http://www.holography.ru/maineng.htm Beautiful Russian Holograms] *[http://www.holograms.bc.ca Royal Holographic Art Gallery] *[http://holographiccenter.com/ Holographic Center] *[http://www.triple-take.com Triple-Take] *[http://www.hologramstore.biz Dragon's Eye Creations] *[http://www.holoshop.nl HoloShop.nl] *[http://www.holoshop.com Holograms & Lasers Intl] *[http://www.geola.lt/show.php?lang=eng&cont=holoindex&lside=holo_index_left Geola - Digital holographic prints - Synfograms - Colour and movement in one] *[http://universal-hologram.com/ Hologram Art] *[http://www.rabbitholes.com/art-gallery/ Holographic Art Prints from Computer 3D and Animation from Leading 3D Artists] *[http://www.rabbitholes.com/order-samples/ Samples kits of Rabbitholes Holograms] ===Links to Professional Holographers=== *[http://www.3dimagery.com Three Dimensional Imagery] Hologram Production Lab *[http://universal-hologram.com/index.htm Cherry Optical] Hologram Production Lab *[http://www.forthdimension.net Forth Dimension] Hologram Production Lab *[http://www.holonorth.com/main.html Holographics North] Hologram Production Lab *[http://www.holographsonmain.com Holographs on Main] Portrait Studio *[http://www.laserreflections.com Laser Reflections] Pulsed Holography Lab *[http://www.zebraimaging.com Zebra Imaging] Hologram Production Lab *[http://www.geola.lt Geola] Synfograms (Geola's digital holograms) - life scene colour imaging with animation *[http://www.rabbitholes.com RabbitHoles Media] Full color digital hologram production ===Organizations=== *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.holography.co.uk/index.shtml Royal Photographic Society] *[http://www.spie.org The International Society for Optical Engineering] *[http://www.IHMA.org International Hologram Manufacturers Association] *[http://www.holographynews.info Holography News - Industry information] 30a3b3abb88157f701f692ed5320165cbe8381dd 0 281 1713 410 2013-05-12T04:08:10Z Jsfisher 1 1 revision wikitext text/x-wiki ==What is a hologram?== Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ==How little money/bother do I need to make one?== You can make your first hologram with about 2 hours of set up and about $100. ==What is the cheapest way to make a hologram?== [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ==Are the chemicals dangerous?== While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ==What sort of time commitment is there for making a hologram?'''== You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ==When can I have the lights 'on' during the procedure of making a hologram?== Once the emulsion has become insensitive to to light. For Silver Halide holograms this is after the hologram is bleached. For Dichromated Gelatin holograms this is after the fixing and rinsing steps. ==What are the different kinds of holograms?== [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ==What is the single most important factor when making a hologram?== '''Stability!''' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ==How Does a LASER work?== For a simple introduction to lasers read [[How Do LASERs work?]]. ==Can I use a cheap red laser pointer to make holograms?== Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ==Can I use a Green Laser Pointer to make holograms?== So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ==Where are the Reference and Object beams in a Single Beam Reflection Hologram?== Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ==Some uses for [[Everyday Items]] in holography== Click here for [[Everyday Items]] that can save you money in holography! ==What is a [[Scratch-O-Gram]]?== A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and ficusing it from a curved scratch to a point. ==What Books are Available for Holography?== See the [[Books]] section. ac4f0c8a6cc507fe2af34cfee09b4bc95831c9f0 0 832 1715 1714 2013-05-12T04:08:10Z Jsfisher 1 1 revision wikitext text/x-wiki [[Media:Holotool.exe|Holotool.EXE]] is a self extracting program that contains four DOS executables and three pcx drawings totaling just 115 kbytes when expanded by running Holotool. It is probably best to run it in it's own directory, so identifying the individual programs is easy. The programs included are as follows: '''EXPAND2.EXE''' is a menu driven program that asks you for the playback and construction wavelengths, the playback and construction bulk index of refraction of the recording media, the external angles for playing back either a transmission or reflection HOE or hologram and the thickness change multiplier expected from your film. The output is the internal Bragg angle, the spatial frequency and the internal and external construction angles for both before and after expansion or shrinkage of the film. The program toggles through remembering what you did and allowing changes to be made to quickly try out a lot of configurations to find out what will probably work and what will not. '''TIR2.EXE''' is just like Expand2 except that the second angle it asks for is the internal playback angle, which allows you to design total internal reflection (TIR) HOEs or edge lit holograms. The output includes a prompting for a best angle prism to index match to the film substrate and allows you to input any angle prism you may have and then outputs an angle for the non prism side and one for the ray entering the prism if a reflection geometry results or two ray angles measured off the normal to the prism in the case of a transmission outcome. TIR fringes hover around 45 degrees of Brag tilt and are especially hard to make correctly so this is the most valuable of the utilities I use myself and the newest of the three programs. '''TIR2.PYW''' (not part of the holotools package) is a graphical version of TIR2, written in [http://www.python.org/ wxPython], for Windows 95/98/NT and UNIX/Linux. To use this program, you will need to download the [[Media:tir2.pyw | tir2.pyw]] program file and the [http://www.python.org/download/download_windows.html Python Interpreter] and the [http://www.wxpython.org/download.php wxPython toolkit]. After installing the wxPython software package, the TIR2.PYW program file will be executable. To learn more about wxPython, go to the [http://wxpython.org/ wxPython home page]. ''Note:'' tir2.pyw is a work in progress. Please send all suggestions or bug reports to rdr@ralcon.com. '''CHIRP.EXE''' is an older Fortran program that models holographic or dielectric mirror stacks using a quarter wave model or Kogelnic's approximation, you get to choose. The inputs are bulk index, center wavelength, film thickness, average expected index modulation, absorption of the holographic film during exposure in percent (gradient), percent change in fringe spacing as a function of depth (chirp) and wavelength range to scan symmetrically around the center wavelength. The outputs are first a plot of index modulation as a function of depth then a plot of density versus wavelength and if you choose to save the file when prompted you can retrieve it with CHIRCALL.EXE and display and print an amplitude reflection plot to use to match up with a spectrophotometer output of a real mirror. This program is useful for measuring the index modulation of a film when things are not linear or uniform as is true for most recording media. There are three GIF files, [[Media:expand2.gif | EXPAND.GIF]], [[Media:tir2.gif | TIR2.GIF]] and [[Media:nchirp.gif | NCHIRP.GIF]] that give sign conventions and further instructions for using their respective namesakes. These are easily read and printed from Paintbrush and many other programs including word processors. For those that prefer to customize their software, the source code for the two C programs is also available by email. [[Category:Rallison]] 9215828f9683a08a0e1e6195a5d16c765c8de873 0 834 1719 1718 2013-05-12T04:08:10Z Jsfisher 1 1 revision wikitext text/x-wiki == Simple Gravity Base == by Dave Battin {| |- |[[Image:CIMG8817.JPG|right]] Here is an example of gravity bases. They are easy to make and quite stable. The items you need are: *12" steel rod, 1/2" diameter *4" section of 3" or 4" PVC pipe *Plaster of Paris *Scraps of steel or lead *Wooden board *3 round head screws (optional) Assemble the base as follows: * Drill a 1/2" hole through the wooden board to accept the rod nicely. * Clamp the board to a workbench top so the the steel rod can go through the hole and stick up above the board by 3-1/2". * Position the PVC pipe section on the board, over the rod. The rod should be off-center. * Fill the PVC pipe with a combination of Plaster of Paris and scrap metal. The metal provides the weight, so the more the better. Feet can be cut into the PVC as shown in the bases depicted here. The round head screws can be set in the plaster instead, providing something of a kinetic mount capability. After a short setting time the base and rod are pulled out off the board and the base is now complete. Paint after plaster is ''completely dry'', usually a week or two(!). |} == Film Holders == Holding the film or plate stable is a prime requirement for making a hologram. Film holders can be as simple as holding up a glass plate with a couple of magnets. But, it must not be forgotten that the film must be held absolutely stable. Film holder Plans: #[[Machined Film holder]] #[[Angle Iron Film Holder]] == Everyday Items == These are just suggestions and the actual results may vary. It is the responsibility of the user of these suggestions to be safe and use common sense. *Heating pads used with three or more settings allow a variable heating to processing trays. Simply put the heating pad under the tray and turn the pad on to the desired setting. *Black foam board can be used for blocking stray light. The type that is black through and through is best as the edge stays black even when it is cut. This material can also be used for making an iris. *A shutter can be made from most old 8 mm movie cameras. They have a low voltage electric shutter. Remove this unit and set up a circuit with the original voltage of the camera and a switch. *A thick piece of glass, a ¼ inch or thicker, can be used as a beam splitter. Using the thick piece of glass allows a small piece of electric tape to be placed over the secondary reflection off the back of the glass. *Sandwich storage containers can be use as processing trays and storage for the chemistry without having to pour back and forth into a bottle. They come in many sizes and shapes with airtight lids. Store sealed containers with chemistry in a dark, dry, cool place when not being used. *Inner tubes can be used as the dampening mechanism between a holographic table and the support legs. *A slab of granite can be used as a holographic table. *Most old overhead projectors have large front surface mirrors and large Fresnel lenses in them. They can be purchased at yard sales and flee markets for just a few dollars. *Most photocopiers and fax machines have front surface mirrors. *New Jefferson Nickels have a weight of 5 grams and new Lincoln Pennies have a weight of 2.5 grams. Standard paper clips have a weigh of 1 gram. To verify the weight of the paper clips put a nickel on one side of the balance and find 5 paper clips of the same size that equals the nickel. These can be used on a balance for measuring out chemicals. *A hair dryer can be used to dry a piece of holographic film or plate after processing. Drying intensity and heat is variable with very inexpensive dryers. *Polarizers can be found in polarizing sun glasses. These can be used to slightly modify the intensity of throughput laser light by inserting it into the beam path and rotating. They can also be used to relatively compare the polarization of light in different locations. *Two pieces of window pane glass and binder clips can be used to sandwich a piece of holographic film. This will hold the film rigid and flat. *A microwave can be used to heat the Deionized or Distilled water needed for mixing up processing chemistry. But please be careful to keep chemistry contaminated containers separate and secure. One method is to heat the water in a clean container in the microwave and then pour it into the chemistry container for mixing, always keeping the clean container free of any chemicals. *Two parts, fast hardening epoxy is great for securing two pieced of metal without the need for drilling and taping. This also allows the disassembly with just a small sharp blow to one of the pieces. *A pinhole can be made by sandwiching 5 or 10 pieced of aluminum foil together and poking with a pin while the pile is on a hard piece of rubber just coming through to the other side. Each piece of foil will have a slightly different size pinhole. *Automobile windshield wiper blades can be used as a squeegee. If you epoxy two blades to a pair of scissors whereas the two blades meet perpendicular out from the cutting surface of the scissors and when the scissors are closed ¾ of the way, you can squeegee both sides of the film at the same time. For plates this is not necessary and one side can be done at a time with one blade. *Clothes pins strung on a line can be used to hang the film when it dries. After clamping the film at two corners with the pins, clamp two more at the bottom corners to keep the film straight when it dries. *Dishwasher drying agent can be used as Photoflo in the final rinsing bath. Use an agent that does not have fragrant and is preferably clear. *Sodium carbonate can be purchased cheaply as a pH increaser for swimming pools and Spas. *Sodium Bisulfate can be purchased cheaply as a pH decreaser for swimming pools and Spas. *Sulfuric acid can be purchased as Automobile battery acid. Most formulas call for concentrations that are lower then the concentration sold as Auto battery acid. *Sanford Sharpie markers, black, which come in different sizes, are ideal for blackening optics, mounts and anything small you want to reduce reflections on. It is a permanent marker that writes on almost anything. *Paper Mate liquid paper correction is a very nice white paint for painting objects for holography. It dries flat white and diffuses the light very well. [[Category:Equipment]] dcb8e7df62404160d3f5e0eac56d6d00667016f6 0 835 1721 1720 2013-05-12T04:08:11Z Jsfisher 1 1 revision wikitext text/x-wiki Jeff Blyth This is a remarkably simple way of making a holographic recording material. This is the way that we make a lot of holograms in our lab, and we find it to be by far the easiest method for making holographic plates. In essence, we treat a glass surface to make it chemically 'sticky', we coat that with gelatin, and harden the gelatin with chromium or formaldehyde. Once we have the gelatin film we then soak into it a silver salt, and subsequently soak in potassium or lithium bromide to precipitate an ultra-fine grain precipitate of silver bromide. The bromide solution also incorporates a dye to make the plate photo-sensitive in the required wavelength range, and with addition of a little sensitiser we can produce by this method a holographic plate of quite high standard. A worksheet (dated Nov 2000) is given below. It gives results which have good diffraction efficiency and photosensitivity compared to ultrafine grain proprietary material. But this is for the fun of doing it all yourself and getting bright results. If you are particularly concerned about marks from bubbles, dust and blemishes then you may prefer to use the proprietary material. The material on this page is based on the following article, with some changes that we have made to our protocols since publication, and any differences between the original article and the text below are solely due to those differences. == A simple way to make silver halide hologram recording plates by Diffusion == By Jeff Blyth Institute of Biotechnology University of Cambridge Tennis Court Rd. Cambridge CB2 1QT Tel: 01223 334152 (fax: 334162) email: jeff@biotech.cam.ac.uk What follows is in the form of a worksheet based on the paper published in ''The Imaging Science Journal'', Vol. 47, pp 87-91, 1999. A text only version of the paper can be found on the Internet at http://www.holoworld.com/holo/paper.html or at http://www.holografie.com/paper.html. === The Basic principle === A coating of pure gelatin on a glass plate is treated with silver nitrate. The coating is then immersed in a bath of bromide ion and dye. This then precipitates extremely fine grains of silver bromide in the gelatin layer. === Materials === # Presubbed glass plates. You can use old holographic plates with the gelatin removed with the aid of household bleach. # Gelatin of bloom strength between 250 and 300 (e.g. 300 bloom from Aldrich cat no. 27,162-4). You can use culinary gelatin without any sugar or flavourings. # Ascorbic acid or Vitamin C. # Silver-nitrate. A 1N volumetric standard solution is a useful form. # Potassium Bromide # Chromium acetate. You can use chrome alum instead. # Dye(s) #* Pinacyanol Chloride for HeNe 633 nm exposure. #* 1,1-diethyl-2,2 cyanine iodide for 532 nm exposure. # Sodium hydroxide # 3-amino-propyltriethoxysilane (for new glass plates). === Concentration of Solutions === Quantities will need to be judged by you to suit your requirements. * Silver nitrate: 6% w/v in (DI) water (or the 1N volumetric standard solution diluted by 1 volume to 2 volumes DI water). * Stock dye solutions. (In practice, you would probably only need one hundredth of a gram to make up a few ml of these somewhat expensive dyes.) ** for 633 nm: 1 g / 1000 ml Methanol. ** for 532 nm: 1 g / 500 ml Methanol. * Potassium bromide: 4% w/v in 3 / 2 methanol / water (3% lithium bromide gives a finer grained hologram than the equivalent concentration of potassium bromide, however 4% potassium bromide works well). * Chromium acetate solution: 1% or Chrome Alum, 2% * Gelatin solution: 15% (see 2 paragraphs down). * Ascorbic acid: 1% solution in water, adjusted to around pH 5 with any alkali. === Preparation of plates === Glass plates usually need a pre-treatment step or the gelatin coating will peal off. You can use old holographic plates by simply giving them a 10 min. soak in neat domestic bleach solution and then rub off the old gelatin layer under tap water. After a final rinse in distilled water, no further subbing step may be required. However with new glass plates, I leave them soaking overnight in a 100% bleach (Domestos or Parazone). After the plates are dry I rub them over with a 1% solution of 3-amino-propyltriethoxysilane in acetone on a tissue until it has evaporated, and leave them in air to interact with the silane for at least two hours before coating. (The silane solution has to be freshly prepared for each batch of plates). === Preparation of coating solution for a 10 x 8 plate === Add 30 g gelatin to 170 ml cold distilled water and mark the liquid level on the beaker. Place beaker in a water bath and heat while stirring constantly until gelatin solution is between 60 and 70o C. Stir until all granules have cleared. Top up level to the mark. To remove skin and surface foam, pour through a fine mesh (nylon stocking works fine) into a preheated beaker. Then immediately proceed to next step: === Coating (by the old Victorian curtain method) === Hold the beaker in your right hand and with you left incline the presubbed glass plate (preheated to around 70oC) at an angle of about 30o to the vertical with its bottom edge in a clean tray. Pour the gelatin in a line about 1 cm from the top of the plate. The pouring rate must be continuous until the furthest edge of the plate is reached. (You may have to accept the tendency of the coating to not completely cover the lower part closest to the furthest edge.) Lean plate against something for a few minutes while coating gels. Run a knife along thick layer at the bottom to free plate rather than risk tearing the delicate coating. (Since no hardener is involved yet the gel can be readily scooped up and re-coated if you are not satisfied.). Put plate in cold solution of chromium acetate for 1 minute. Shake off drips and then (without washing away that salt) blow plate with cold air until dry. Once the layer is dry leave the plate to complete the chrome hardening effect overnight in a warmer. (Preferably at around 60oC for several hours). Rinse the hardened plate in DI water and dry in a warm air flow. If you want to cut plate up for the next step then after scoring the glass on the back and cracking it, it is best not to pull sections apart before running a scalpel blade along the gelatin side first so that it is cut and not torn apart. Alternatively a Meyer bar can be used. About 7 turns per cm. === AgBr loading operation === # For a 5 x 4 plate place approx 3 ml 6% silver nitrate solution in the centre and at once squash it with a clean flat cover plate (preferably transparent plastic so that you can see the air bubbles are squeezed out). Leave for 3 minutes. Safelighting is not strictly necessary here but white lighting should be subdued. # Remove cover plate and immediately remove the excess silver solution on its surface by gently brushing over the plate with a soft squeegee (windscreen wiper blade). # Blow dry plate with cool air. Once dried, the plates can be stored for a short while in a cool, dry, dark location until needed. # Under safelight conditions, add 2.5 ml of dye solution per 100 ml of potassium bromide solution, add about 0.5 ml of 1% ascorbic acid solution (this is the same solution as is used in the final sensitizing bath) agitate the bath and plunge plate in while maintaining the agitation for about 2 minutes (although with softer gelatin this could be reduced to 60 seconds, otherwise unacceptable grain growth can occur. Expect to spend a little time optimising this step for your own application). This solution can be re-used a number of times, until such a point as the dye starts to come out of solution or the brightness of the resultant holograms seems to be diminished; the dye used for 532nm exposures (see above) is far more re-usable. # Rinse well under running tap water (any AgBr only on the surface can be removed by gently rubbing with ungloved finger.) Plates usually come out this bath beautifully clear under the green safe light, without any surface deposit. # Sensitizing bath step #: The plate can be immersed for 1 minute in 1% ascorbic acid solution adjusted to pH 5 using a little sodium carbonate or hydroxide. Alternatively, the well known triethanolamine pre-swelling technique can be used with the advantage of increased brightness at a shorter wavelength. (Prolonged settling period may then be necessary however to avoid creep while the exposure is being made). After exposure the plate is then developed as per the first part above. 7260df0259b738716a537b3cf10576570c271140 0 284 1723 416 2013-05-12T04:08:11Z Jsfisher 1 1 revision wikitext text/x-wiki [[http://www.hololab.com/ Ikuo's Web Site]] 200725896d40d33e07643c6a48fa314af6f00dc5 0 836 1725 1724 2013-05-12T04:08:11Z Jsfisher 1 1 revision wikitext text/x-wiki Please note that these pages are currently in the process of being placed online. Some images and formatting from the original published version may still be missing. * [[Control of DCG and non silver holographic materials]] * [[Polarization properties of gelatin holograms]] * [[Blazed Binary Optics, From PC to Plastic]] * [[Media characteristics, tables and plots]] (lots of images) * [[Phase materials for HOE applications]] [[Category:Rallison]] 7a29257397e8075665e8284ea4fd895a41a9f840 0 837 1727 1726 2013-05-12T04:08:11Z Jsfisher 1 1 revision wikitext text/x-wiki 8501 S 400 W<br> Paradise, UT 84328 == From Salt Lake City to Logan == [[File:map_big.gif]] * First thing is to find I15 (shouldn't be hard). * Follow it to exit 362 (Brigham City) == From I15 Exit 362 to Paradise == [[File:map_canyon.gif]] * From I15 Exit 362, head into Wellsville Canyon. * Not long after exiting the canyon there will be an exit marked "Mt. Sterling." * The exit is easy to miss. If this should happen, try for the Hyrum exit. * Following either exit (or even going into Logan) will lead to Highway 165. * Follow HW 165 South until there are only trees on the right and hills on the left. == Getting to Ralcon Dev. Lab from Paradise area == [[File:map_paradise.gif]] * From HW 165, either: *** Get off on 7800 S (hidden in the trees) *** From westbound on 7800 S turn left. *- OR *** Follow the road to 8700 S (Car Service) *** From westbound on 8700 S turn right. ''Last modified on 1/03/2005'' [[Category:Rallison]] 786ee39ba31bb27086aee7fd9b24fc4374460aaf 0 395 1729 942 2013-05-12T04:08:12Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:JBlyth.jpg]] a129eecfa2418870c4dc76082d5783d2808450ed 0 397 1731 946 2013-05-12T04:08:12Z Jsfisher 1 1 revision wikitext text/x-wiki Sorry, I had more of a holography history for me then a biography. I have an AA degree from a local Community College with an emphasis in Computer Science. I furthered my education at University of Maryland with Physics, Math and Computer Classes. I am a Microsoft Certified Systems Engineer and presently design Wide Area Networks. I have worked at North East Holographics and responsibilities included: Design, configure and produce H1 multi-channel rainbow master holograms for replay with a HeCd laser using a large frame Argon Ion laser. Design, configure and produce H2 rainbow copy holograms in Photoresist utilizing a fringe locker to help with stability during the long exposure times and using a HeCd laser. Fabricate Photoresist emulsions on glass plates. Implemented quality control of Photoresist plates. Silverized the Photoresist plates with an atomizing spray system. Built, maintained and controlled variables for producing different types of Nickel Shims made from the Silverized Photoresist plates. Built, maintained and operated a complete wide format Embossing Printer used to hot stamp nickel shim hologram in foil backed plastics. I have also been involved with amateur holography since 1982 working with Silver Halide. Currently and for the past 3 years I have been concentrating my efforts in working with Fabrication and production of Dichromated Gelatin holograms implementing a variety of techniques formulas and geometries. I have moved from the basement to a dedicated lab. f03f3c53cb3b477bcc67f54174be4a09264d507c 0 398 1733 948 2013-05-12T04:08:12Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Jross.jpg]] JONATHAN ROSS [http://www.jrholocollection.com WebSite] CURRICULUM VITAE BORN 1953 London EDUCATED Bryanston School, Dorset 1970 - 71 Studied Art History in Venice and London 1972 - 77 Worked as assistant in Film Production and Theatre Management 1978 - 79 Founded and managed The Hologram Place - The first European gallery devoted to holography 1978 - 90 Founded and managed SEE 3 (HOLOGRAMS) LTD. - a production company for the manufacture of display holograms 1992 Organised “Four British Holographers” exhibition at Smith’s Gallery Covent Garden 1993 Organised “Landscapes & Metamorphoses” exhibition at Smith’s Gallery 1994 Organised “3x8+1” a selection of holograms from personal collection at Milton Gallery, St.Paul’s School, London 1995 Contributed selection of holograms to “Holograms from around the World” James Dun’s House (Aberdeen Art Gallery) Guest curator of “The Art of Holography” at the National Museum of Photography, Film & Television, Bradford 1996 Co-curator of “Raum in Sicht - Magie in 3-D”, Technorama Switzerland. Special Consultant to Art in Holography2 Symposium, Nottingham University Exhibited selection from collection and gave paper on collecting holograms. 1997 Exhibited selection from collection at The Royal Photographic Society, Bath. 1998 Founded Gallery 286 in Earl’s Court Road, London and has curated an ongoing programme of exhibitions featuring holographers, photographers, painters and sculptors. Over 50 exhibitions to date, including one-person shows by John Kaufman, Andrew Pepper, Margaret Benyon, Matthew Schreiber, Jon Mitton and Pearl John 1999 Advisor to the Shearwater Foundation Holography Award Programme 2000 A special Exhibition of work selected from the collection at The Butler Institute of American Art, Youngstown, Ohio, USA The Royal Photographic Society Holography Group Summer Exhibition 2000. A selection of work from the Jonathan Ross Collection. 2004 Received The Royal Photographic Society Saxby Medal for contributions to 3-D Image-making 1988 - 93 Consultant Editor, Art Line International Art News 1983 - Hon.Treasurer, Royal Photographic Society Holography Group During his long association with holography, Jonathan Ross has assembled one of the world's most extensive collections of holograms, details of which can be found at http://www.jrholocollection.com c493b47d5163d6f4898344f036ba3f16f3772b6b 0 399 1735 950 2013-05-12T04:08:12Z Jsfisher 1 1 revision wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 400 1737 952 2013-05-12T04:08:12Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:JUpatnieks.jpg]] Director of Applied Optics Ann Arbor, Michagan Professor, Electrical and Computer Engineering Department University of Michigan Mechanical Engineering and Applied Mechanics Department University of Michigan Born: May 7, 1936, Riga, Latvia ---- ==List of Patents== *3,506,327 Wavefront Reconstruction Using a Coherent Reference Beam, 1970 *3,532,407 Spatial Frequency Reduction in Holography, 1970 *3,539,241 Method of Imaging Transparent Objects with Coherent Light, 1970 *3,545,835 Two-Beam Holography with Reduced Source Coherence Requirements, 1970 *3,548,643 Holographic Vibration Analysis Method and Apparatus, 1970 *3,580,655 Wavefront Reconstruction", 1971 *3,637,313 Method of Imaging Transparent Objects with Coherent Light, 1972 *3,677,617 Technique of Holographic Data Reduction Utilizing an Additional Diffusing Structure During Reconstruction, 1972 *3,748,048 Method of Detecting Changes in Specular Surface, 1973 *3,838,903 Wavefront Reconstruction, 1974 *3,894,787 Holograms, 1975 *4,012,150 Holographic Light Line Sight, 1977 *4,057,317 Hologram Projector, 1977 *4,223,975 Aberration Correction of Magnified Holographic Images, 1980 *4,277,137 Coherent Optical Correlator, 1981 *4,643,515 Method and Apparatus for Recording and Displaying Edge- Illuminated Holograms, 1987 *4,711,512 Compact Head-Up Display, 1987 *5,151,800 Compact Hologram Displays and Methods of Making Compact Hologram, 1992 *5,483,362 Compact Holographic Sight, 1996 6d18e713af1529cd397829690649fa163d236a5a 0 404 1739 960 2013-05-12T04:08:12Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:KBazargan.jpg]] Optics has interested me ever since I was a small child. Everything from how a movie was projected in a cinema, to why shadows were sometimes sharp and sometimes not, constantly occupied my mind. This inquisitiveness finally led to a masters degree in Optics, at Imperial College, London. Here I developed an interest in holography, so I stayed on to complete a PhD in Display Holography. I have uploaded the thesis [http://www.focalimage.com/public/kaveh-PhD.pdf here]. The two areas I worked on most were natural color holography, and dispersion compensation. For colour holography I proposed using the three "prime" colors (as first identified by W A Thornton in 1971) for image recording. The work on dispersion compensation led to a compact hologram viewer which was patented, and is now marketed as the [http://www.apple.com/science/profiles/voxel/ "VoxBox"]. After 5 years of research in holography I was distracted by the fascinating emergence of "desktop publishing", and set up a graphics and typesetting [http://www.river-valley.com company] in 1988, which is now established and pays the bills. I am now raising my head again in holography and hope to continue where I left off. [http://www.holographer.org The Holographer] represents my re-entry into the field. 28734756aa7636407946e6d306646253d4cc12ec 0 405 1741 962 2013-05-12T04:08:12Z Jsfisher 1 1 revision wikitext text/x-wiki A knife is a broad word encompassing a large number of tools. The cheapest knife to buy and maintain is an x-acto knife. [[Image:XactoNo1.jpg]] The no. 1 knife handle with the no. 11 blade is the most common knife we associate with X-Acto but they make a broad product line for model makers. The blades are stainless and never get as sharp as a steel blade. [[Image:XactoX2000.jpg]] A more comfortable handle is the X-2000. X-Acto knife blades are cheap enough that sharpening is not required. The blades are simply replaced. [[Image:ViolinMakersKnives.jpg]] A better knife is a violin makers knife. You can sharpen the blade and trim back the handle for a lifetime. They are available in German steel and Japanese Steel. The German steel is more durable (chips less easily). The Japanese steel gets sharper and stays sharp longer but chips quite easily. ===Sharpening Knives=== Sharpening knives is a task of patience. You must completely sharpen one face to completion before moving on to a finer grit. You may stop at anytime the knife is sharp but what is described below will make a knife sharp enough to shave. [[Image:KniveAngles.jpg]] The angle you sharpen at is chosen based on what the knife will be used for. Use a blunt angle for rough work and a durable blade and use a sharp angle for delicate work. [[Image:KnifeSharpening.jpg]] *Rough out both sides in a single plane with a course stone. *Polish the faces with a fine stone. *Hone the knife on a leather strop with red compound (rouge). *Hone the knife on a 2nd leather strop with white compound. [[Image:KnifeSharpeningStages.jpg]] Tips: *Do not switch to fine grit until all chips have been removed. *Be careful to not round the edge. You need one plane from the shank of the knife to the edge. *Sharpen both sides evenly. Safety Tips: *Do not pull a knife towards your body or fingers. [[Image:KnifeSharpeningTips.jpg]] ===Links=== [[http://www.frets.com/FRETSPages/Luthier/Technique/ToolUse/KnifeTechnique/knifetech01.html Master Luthier Frank Ford on Knives.]] eb1ce34b412a47edb5796a31f60ae8807c389e3b 0 838 1743 1742 2013-05-12T04:08:13Z Jsfisher 1 1 revision wikitext text/x-wiki * [http://www.noao.edu/ets/vpgratings/ volume phase gratings] '''''Lidar links:''''' * [http://q.eisl.harc.edu/~www/ Houston applied Research lidar] * [http://bll.gsfc.nasa.gov/ Boundary Layer Lidar] * [http://rsd.gsfc.nasa.gov/912/code912/raman.html Scanning Raman Lidar] * [http://virl.gsfc.nasa.gov/lazer/index.html Holographic Optical Telescopes and Scanners] * [http://bll.gsfc.nasa.gov/harlie/ HARLIE] * [http://harlie.gsfc.nasa.gov/ HARLIE] (Holographic Airborne Rotating Lidar Instrument Experiment) '''''Misc links:''''' * [http://www.familysearch.org/ Dead People] (geneology) * [http://www.geocities.com/TheTropics/3053/part103.html FAR part 103] * [http://tycho.usno.navy.mil/cgi_bin/timer.pl Time] * [http://www.wasatchphotonics.com/index.html Wasatch Photonics] * [http://www.i-glasses.com/ I-Glasses] * [http://www.terabeam.com/ Terabeam] ''Last modified on 9/13/00'' [[Category:Rallison]] a97696fa92fbaa40e0cd4ed378445051ddd43e02 0 423 1747 997 2013-05-12T04:08:13Z Jsfisher 1 1 revision wikitext text/x-wiki == Lon Moore == Lon Moore was one of the first holographers to mass produce reflection holograms of popularized imagery. During the 1970s and 80s, he succeeded in experimenting with different processing techniques, controlling the available colors produced by the predominantly monochromatic medium and using his chemical palette appropriately in each of his holograms. Moore was a director and instructor of the San Francisco School of Holography and has exhibited his work at numerous venues in the US and Canada. 441554dfb57afedc7d68bcf72dce2d822333f6fe 0 424 1749 999 2013-05-12T04:08:13Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Lcross.jpg]] ad8cf59eb04fa1975b0157f132d7cf769aa2afcf 0 428 1751 1007 2013-05-12T04:08:14Z Jsfisher 1 1 revision wikitext text/x-wiki ====A Machined Film Holder==== [[Image:FilmHolder.gif]] by: Colin Kaminski '''4" x 5" Film Holder''' after Dinish and Joy Padyir's. This film holder is a copy of one Dinesh and Joy were using when I was there. I made it from 3/4" square aluminum bar. (This is not quite how I made it but I am going to include how I would make it again when I make a second one this week.) Take a 12" or so section of 3/4" aluminum bar and set a table saw to cut .25" deep. Set the fence .125" from the blade (make sure the fence is parallel to the blade!) Run the piece of aluminum through. (Use two push sticks so you don't get your hands anywhere near the blade. Also a feather board or two would be of use but I did not have any handy.) Then move the fence over about .035 inches or however wide you want the slot. You can make the slot wide enough to accommodate 2 plates and film if you wish. Then hack saw it to 4.25" or so. (Where the table saw blade exited the part you will notice the slot is wider than the rest of the part. This is because the blade started to ring upon exit and you should make sure to cut off this end.) Set up your cross cut saw on your table saw very square then taking about .030 inches in a pass trim both ends until the ends are clean, square and the piece is exactly 4". Cut another piece to 6+ inches and clean up the ends on the table saw till it is square and 6" long. Measure down the 4" pieces 1" from each end and make a line. Measure from the lip .125" and make a line. Where these lines intersect, use a drill press and drill a #36 hole through to the channel. (Marking the hole with a spotting dril is handy to keep the wholde from drifting. At least make sure you have as little of the drill bit sticking out of the chuck as posible and mark the spot with a punch.) Tap to #6 32 tpi. These will be the plate holder screws. (Note: tap from the small side for a reflection plate holder and from the thick side for a transmission holder, or you can make two slots in the same plate holder.) Mark the two 4" pieces on the ends in the center. (This operation will make the parts "Handed" so make sure to pick opposite ends for this mark.) Drill in a drill press a #F hole about 1/2" deep. Tap to 5/6" 18 tpi. Measure .375" up and over on the 6" pieces (on the 6" face) and make a mark at each end. Drill through with a 5/16" drill bit. (If you miss this hole or the holes in the ends you can make this hole larger so you can get the parts to align.) In the center of the bottom of the 4" pieces (away from the slots) drill a #7 hole .425" deep. Tap with a 1/4 20 tpi tap. In the center of the 6" piece, on the same face as the holes, drill a #7 hole .425 or so deep and tap to 1/4" 20 tpi. These will be the mounting holes. Clean up the corners with a file, and clean up the holes with a countersink tool. Spray paint with Krylon Ultra flat black paint. Bolt channels to the bas with 2-5/16", 18 tpi, 1" long Allen bolts. Put 4 #6 32 tpi Allen bolts into the channels but first file the ends flat with a 6" mill smooth file. The length should be chosen so it sticks out about .25" when holding a plate. Put 3 1/4", 20 tpi, .75" long Allen set screws into the tapped holes. These now will fit any 1/4" mounting rod. Spray paint with Krylon Ultra flat black paint. My total time invested was three hours. A nice touch would be to bevel the front side of the plate holder to 45 deg. You can easily do this with a router and a bearing bit. What you say? Cut aluminum with wood working tools? The truth is it works very well and I have been doing it for years. It works much better than many woods and it is much faster than milling. I once purchased a 9 HP pin router from Boeing that was used to rout airplane parts. We used it to make electric guitar bodies. If you were going to use your table saw a lot for making aluminum parts I would use a ATB grind 60 tooth blade with large blade stiffeners. 3bfa786fa94a0c5a6ddaa4a3b362979c856c775e 0 1 1753 1349 2013-05-12T04:08:14Z Jsfisher 1 1 revision wikitext text/x-wiki Welcome to the [http://www.holographyforum.org Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms. * [[Abbreviations | '''Abbreviations''']]. Commonly used abbreviations by holographers. * [[Holography for Beginners | '''Holography for Beginners''']]. An FAQ for beginning holographers. * [[Holography Technology | '''Holography Technology''']]. The hardware and setups for making holograms. * [[Hologram Recording Materials | '''Hologram Recording Materials''']]. How to get, make and use them and chemistry. * [[Holography Theory | '''Holography Theory''']]. The Mathematics and Science of Holography. * [[History of Holography | '''History of Holography''']]. The timeline of the people and technology. * [[Holography Safety | '''Holography Safety''']]. Chemical and laser safety. A must read! * [[Biographies of Holographers | '''Biographies of Holographers''']]. The people who have made it all possible. * [[Holography Links | '''Holography Links''']]. Other resources for holographers on the web. * [[Holography Glossary | '''Holography Glossary''']]. Holography technical terms defined. * [[Archives | '''Archives''']]. ba1885126b81eca80a165938aa116099c64399ac 0 432 1755 1015 2013-05-12T04:08:14Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.mbenyon.com Margaret Benyon's Website] [[Image:Mbenyon.gif]] Initially a painter, Margaret Benyon began to make holograms in 1968 when holography was available only to scientists. Her aim was to take holography out of the science lab, and to enlarge the boundaries of what was traditionally seen as fine art. Her early body of work with holography was an exploration of those aspects that were unique to it. Living in Australia with her partner and two small children in the 1970's led to work that was more humanist and cross-cultural. On returning to the UK in 1980 she began to use the human body exclusively, in a personal, partly therapeutic way. More recently she has been exploring the naturalisation of holography, and the female aesthetic. Her work with creative holography has been recognised with academic fellowships, artists' residencies, and a number of other art and holography related awards. She is currently listed in the International Who's Who, and in the millenium year she was awarded an MBE by HM the Queen in the New Year Honours List 2000 for services to art. Her work has been seen in a large number of exhibitions, in countries as far apart as the USA, Canada, Portugal, Italy, Australia, France, Germany, Japan, and China. Her works are in a number of public collections, including the Australian National Gallery and the Victoria and Albert Museum, London, and in an undocumented number of private collections world-wide. In 1994 she received a Ph.D. from the Royal College of Art, London, for her research and activities in art holography. Margaret Benyon made most of her holograms in her home studio on the south coast of England for 23 years. This was a basic, low-tech, non-commercial holographic studio, one of very few in existence. However, she also used more sophisticated international labs, and in 2005 moved to Sydney, Australia. She is currently an honorary Professorial Visiting Fellow at the College of Fine Art at the University of New South Wales, and continues to work internationally from Australia. 20b96fb2add961d59d6fccd5865f3ffb6498dacc 0 433 1757 1017 2013-05-12T04:08:14Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Mmueller.jpg]] Martin Mueller Born and lives in Zurich, Switzerland. Used to work as a freelance journalist, essay writer and translator. Caught the holography virus (1980) when writing an essay on holography (which put emphasis on forerunners in the arts mainly). Run a small holography business with Ralph Kuehne for more than ten years. 1998 begin of friendship and cooperation with Sergio Oliveira (Sao Paulo, Brazil), which led to the development of a new photopolymer system [http://www.polygrama.co.nr/ Polygrama]. cfd3ff4e3ecac1d5d56db9280a1b575f0b50d346 0 839 1759 1758 2013-05-12T04:08:14Z Jsfisher 1 1 revision wikitext text/x-wiki [[File:deltan.gif|center|Exposure vs. density]] {| border=1 |- | Material || DCG || DMP128 || PVK |- | Sensitivity (mj/cm²) || 2-100 @ 442-532 || 30 @ 633-694 || 20 @ 488-532 |- | Approximate available index mod (Delta n) || 0.25 || 0.20 || 0.20 |- | Max O.D. attained in notch filters || 5 || 4 || 2.5 |- | Useful thickness range (microns) || 5-25 || 7-15 || 5-10 |- | Available Spectral Bandwidths (nm) || 10-150 || 10-100 || 20-100 |- | Playback compared to record wavelength || red shift for broad and/or blue shift for narrow | variable blue shift || red broad/blue narrow |- | Minimum recommended protection || 40 mil glass and epoxy || 4 mil Aclar || 4 mil mylar |- | Resistance to water || poor || fair || excellent |- | Familiarity or experimentation period || 13 years || 6 mo. || 6 mo. |- | Number of samples made || 100 || >200 || >50 |} Notch filters or conformal reflectors where made in each of these materials and also in some of Dupont photopolymers. The dupont products have typically smaller bandwidths and lower maximum available index modulation, but the sensitivity is now in the 10 to 20 mj/cm*cm range and the sensitometric curves are similar to the DMP 128 curves in shape. The migrating photopolymers can not be over exposed in the reflection configuration and are fixed by white light or UV flood exposure or over exposure to laser light. == DCG #1 BB == [[File:pg29-1-l.gif|center|DCG1 BB]] {| border=1 |- | n = 1.560 || nl = 0.180 || d = 9.00um || lambda center = 550.nm |- | colspan=4 | Scan from 325.000 nm to 775.000 nm |- | colspan=2 | Minimum %T = 0.0365 || colspan=2 | Maximum %T = 99.9966 |- | colspan=2 | Multiple layer dielectric theory || 38.00% Damping || 9.00% Chirp |} [[File:pg29-1-r.gif|center|DCG1 BB]] {| border=1 |- | n = 1.560 || nl = 0.180 || d = 9.00um || 38.00 % Damping, 9.00 % Chirp |- | colspan=4 | Scan from 325.000 nm to 775.000 nm |- | colspan=2 | Maximum OD = 3.437 || colspan=2 | Minimum OD = 1.479E-05 |} == DCG #2 MB == [[File:pg29-2-l.gif|center|DCG2 MB]] {| border=1 |- | n = 1.560 || nl = 0.140 || d = 9.03um ||lambda center = 525.nm |- | colspan=4 | Scan from 300.000 nm to 750.000 nm |- | colspan=2 | Minimum %T = 0.0030 || colspan=2 |Maximum %T = 99.5860 |- | colspan=2 | Multiple layer dielectric theory || 36.00% Damping || 3.00% Chirp |} [[File:pg29-2-r.gif|center|DCG2 MB]] {| border=1 |- | n = 1.560 || nl = 0.140 || d = 9.03um || lambda center = 525.00nm |- | colspan=4 | Scan from 300.000 nm to 750.000 nm |- | colspan=2 | Maximum OD = 4.522 || colspan=2 | Minimum OD = 1.802E-03 |- | colspan=2 | Multiple layer dielectic theory || 36.00 % Damping || 3.00 % Chirp |} Reflectors in 10 microns of DCG can be processed to have all of the above characteristics. The time, temperature and alcohol concentrations all affect bandwidth and density. == Refractive index change as a function o fdepth for 901 points == [[File:pg30.gif|center]] Model of chirp in spacing and gradient in delta n Broadband effects in DCG, DMP 128 and other materials arise from processing induced chirps in the spacing of the fringe planes much like the variable spacing and amplitudes shown here. Absorption of light during exposure contributes to a broader bandwidth by introducing an exposure amplitude gradient in the index modulation through the depth of the film. The processing gradient caused by the diffusion of developers or solvents into the film may enhance or reduce the gradient depending on whether the film was exposed film side up or film side down (especially in a single beam configuration). This explains why two single beam reflection holograms can appear to be very different in color and bandwidth if one was shot film side up and the other film side down. This plot and the previous plots of amplitude and density and the following plots for DMP 128 were modelled using a program that takes into account a linear chirp in spacing and an exponential gradient in refractive index modulation resulting from absorption of the exposure light. A newer version will plot curves that have nonlinear chirps and generates shapes that more closely match those obtained in a scanning spectrophotometer. == Effects of gradient in n on polarizer performance == [[File:chirp.gif|center|Chirped DCG Reflector]] ''most S light reflected in high delta n region''<br> ''spectral bandwidth is approx. 150nm'' Another way to view the chirp in a plain mirror is shown above where the additional effect of a varying average n through the film is also seen. The fringes near the surface are seen to have wide spacings reflecting Red light with high efficiency because the delta n is highest there. As light travels deeper in finds shorter paths, higher n and lower delta n. The changing n makes a difference in the internal reflection angle, but not the external. This reflector acts as an efficient polarizer for green light because no P polarized light can be internally reflected. It is quite good at other colors as well. [[File:pg34.gif|center|Reconstruction wavelength in nm]] '''Dicromate as % of gelatin by weight''' The Color that DCG reconstructs at can be controlled by how much sensitizer and other dissolved solids are contained in the film before exposure. The sensitizer is washed out and the film loses from 5 to 30% of it's original thickness but processing causes 10 to 50% swelling, depending on how thick the film is and how hot the solvents are and on ph and an time and prehardening among other things. [[File:pg35.gif|center]] Color control can be done easily and repeatably in films of 8 to 20 microns by simply controlling the concentration of dichromate and keeping all processing steps conservative and constant. The graph above is a rough guide to reconstruction colors as a function of two popular exposure wavelengths and dichromate concentration. These numbers are typical of 8 to 10 micron films processed for 1 to 2 minutes in fixer followed by 30 seconds in each water and alcohol bath. The alcohol was about 49 deg C (120 degrees F), as usual processes vary with gelatin selection and condition. [[File:spindev.gif|center|Spin coating]] '''Spin coating at 70 to 100 RPM The thickness of a DCG film may be controlled with wire thickness and water concentration when using a meyer bar or may be controlled with rotation speed and water concentration on a simple turntable made from an old phonograph player. The graph above gives approximate thickness of a standard mixture of 10 grams of dichromate and 30 grams of gelatin in from 400 to 100 ml of water at 60 degrees C. 40 to 50 micron films are spun at 70 RPM, most others are at 100 RPM. Films over 20 microns thick stick to glass better if they are baked for at least 1 hour at 150 deg F and in water saturated air. [[File:spincoater.gif|center|Spin coater]] '''Spin coater''' [[File:dcgtime.gif|center|Process time in minutes]] Processing is either a cool single phase low modulation method or a warmer 2 phase higher modulation process. In between is an unstable region that will produce blotchy reflection holograms where the color difference between blotches is on the order of 50 nm or so. The unstable region is also defined by alcohol/water concentration and again depends on the source and condition of the gelatin. It is sufficient to know that it exists and that it may be avoided by changing temperatures or specific gravities up or down. Film thickness also strongly affects the choice of processing. Thin films are best done in such a way as to maximize the delta n and this is done with hot baths and short process times. Thick films require low delta n to take advantage of the angular and spectral selectivity available in thick films and are best processed at or near room temp for long times in each bath. The plot above is a guide to a starting point, the dots are regions we have worked in. ''Last modified on 6/3/99'' [[Category:Rallison]] 21a5a9b7cd92b01473e85f70bb35d6a69c9b6fa4 0 435 1761 1021 2013-05-12T04:08:15Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:MichaelHDag.jpg]] Born in Houston, TX in 1966 I became enamored with holography in 1984 soon after seeing the first National Geographic with a hologram of an Eagle on the cover. Up to that point I'd never asked for much beyond the typical geek-oriented holiday and birthday gifts such as telescopes, microscopes, circuit kits and the like but that summer I bought the Holography Handbook and soon after asked my parents for a laser. My mother liked to tell the story that after I asked for a laser she called up my father and said "he finally asked for something. He wants a laser." Unlike all her other kids I didn't ask for a car (I was 18 by this time) but asked for something right out of left field as far as they knew. My dad scrouged a .5mW laser out of a telecopier and I set about building a 4'x4' sand table in my bedroom. I made a few transmission holograms over the next year but nothing wonderful. I did end up cracking the foundation though. Fortunately my parents were forgiving. Since diving back into holography in 2003 I've made hundreds of holograms, some not worth keeping but I keep most anyway and have made many more worth keeping, selling, giving away to friends and associates as well as hanging on my walls. I enjoy sharing what I know in person, on the Holography Forum, through the PCG and tutorials on my web site. The full body of my work is available on my web site at [http://holography.dragonseye.com Dragon's Eye Holography] a31af0d54055130efaef6b2f1b52b60d7a75bb74 0 455 1763 1061 2013-05-12T04:08:15Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Pchristie.jpg]] [http://www.litiholographics.com Liti Holographics] Company founder, President and Chief Technology Officer Mr. Christie has extensive knowledge and experience in developing optical systems. Prior to completing graduate work in holographic & three-dimensional display technology at MIT, one of the world’s leading media labs, Mr. Christie was responsible for inventing several new technologies for improving LCD projection displays for Projectavision, Inc., one of which was patented. His Masters Degree work is also currently being patented by MIT. He subsequently formed the predecessor company to Liti Holographics in December of 1997. He holds a Bachelor's degree in Applied Physics from Columbia University and a Master's degree in Media Technology from MIT. 5a55966785e353be7412e05b6f4cac2af30114d6 0 456 1765 1063 2013-05-12T04:08:15Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:Barefoot.jpg]] == ''Paul D. Barefoot'' == ''President:Holophile, Inc.'' Paul Barefoot saw his first hologram in New York at the International Center of Photography exhibition, ''Holography '75: The First Decade'', produced by Jody Burns and Posy Jackson. It was there that he caught "Holography Fever." Within months, he moved to New York from his hometown of Charlotte, NC, where he was Director of Marketing for a graphic arts company and a C130 pilot with the North Carolina National Guard. In November, 1975 he founded Holophile, Inc. to market holography to corporations and nonprofit clients. He also began an affiliation with John Bliss Associates, Inc. (later, Bliss, Barefoot & Associates, Inc.), who served as Public Relations counsel to the Museum of Holography from its inception in 1976. In 1977, Barefoot worked with Museum of Holography founder, Rosemary Jackson, to organize a traveling exhibition of the Museum's inaugural exhibition, ''Through the Looking Glass''. It opened in Toronto and traveled to art, science and children's museums throughout the U.S. Public response was overwhelmingly positive.The exhibition was booked with institutions continuously for ten years -- not returning to New York until its retirement in 1987. During that time, Barefoot took ''Looking Glass'' to Australia for an appearance at the Adelaide Festival of Arts, and to Jerusalem where it broke the all-time attendance record at the Israel Museum In1988, Barefoot began circulating the Museum's second traveling exhibition, ''FutureSight: Innovations in Art Holography''. This exhibition, curated by Rene Barilleaux, traveled to art museums and galleries in the U.S., plus a tour of four New Zealand museums in Auckland, Wellington, Christchurch and Dunedin. In 1992, Barefoot organized a new traveling exhibition entitled, ''The Nature of Holography''. A second show (of the same name) was developed in 1993 to meet the growing demand by art, science, and children's museums. A third exhibition, ''Holography: Making Faces'', was introduced in 2007. These exhibitions, which feature images from the Holophile Collection, are still in circulation. (See complete listing of host institutions since 1977 [http://www.holophile.com/html/exhibit.htm]) Since founding Holophile in 1975, Barefoot has worked as a producer of custom holograms for use by corporate, not-for-profit and government clients, including The American Gas Association, BP Oil de Venezuela S.A., Canary Islands Tourism Board, The Coca Cola Company, IBM, National Security Agency (NSA), M & T Chemicals, Inc., PricewaterhouseCoopers, Samsung Electronics, Pfizer Pharmaceuticals, Raytheon Canada, Ltd and The Weizmann Institute of Science. Barefoot continues to work in holography and other three-dimensional imaging technologies through his company, Holophile, Inc. ([http://www.holophile.com]), located in Killingworth, CT. e3695ac1ee3b828098db5f06e1b85e20e4577af6 0 457 1767 1065 2013-05-12T04:08:15Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.pearljohn.co.uk/holography.html Pearl John] b2b34e9bdb5d899ee8a717fcc8499bb6e2e76a03 0 458 1769 1067 2013-05-12T04:08:15Z Jsfisher 1 1 revision wikitext text/x-wiki http://secure.netroedge.com/~phil/IRs/DSCN1472.jpg (high speed near-infrared photo from a digital camera (Nikon Coolpix 995) I modified just minutes before this photo was taken. I was staring in amazement at the LCD display while I snapped this picture. [http://holographyforum.org/phpBB2/viewtopic.php?t=2043 more on this]) I'm a scientist, engineer, and a wanna be entrepreneur. I was a Linux kernel developer for a while ([http://secure.netroedge.com/~lm78/ the project] still runs strong with the help of others), I have a degree in both computer science and computer engineering (the first is mostly software, the other hardware). I'm a weak lab sort. I'm impatient. For example, I hate movies, they take too long. So I spend a vast majority of my waking hours doing work on a computer (I prefer Linux for work, I support Macs at work, and have a few Windows machines for games and evil proprietary needs). I'm the IT, IS, DBA, telephone, sometimes backend web programmer, and general tech support guy at a small advertising/graphic design agency. As far as holography goes, I got amazed with holograms and lasers in middle and high school. At the time, though, it was expensive, very vague, and sometimes dangerous. Alas, I was completely unsuccessful at creating a hologram, and most likely I found out much later due to some useless Kodak film that was pushed on to me. My doubts lifted when I made a hologram in an unused bathroom at high school during electronics class (the closest thing to a hands-on science class at the time) using Agfa film (which at the time seemed to be getting very hard to get). Later, it was only after finding out about the Holography Forum that I got back into making, buying, and helping those making holograms (where I can) that I got back into the hobby. I'm proud to help Colin, Michael, John, and the many others who work hard to make holography less a monopoly, less scary, less mystical, and simply fun and creative. (PS- I have a problem with using too many parenthesis (as if you didn't notice!), but deal with it! This is my space! ;') [[http://www.holographyforum.org/HoloWiki/index.php?title=Talk:Phil_Edelbrock&action=edit Have a comment? Click here.]] b369b63998b6e7936230988f6be9e6eb7d09479b 0 840 1771 1770 2013-05-12T04:08:16Z Jsfisher 1 1 revision wikitext text/x-wiki Dichromated gelatin (DCG) exhibits variable changes in effective refractive index (n) from 1.54 before exposure to less than 1.25 as it expands during processing. This aerogel like effect causes aberrations in diffractive optics and Kogelnik's theory predicts strong polarization separation in gratings at many different angles other than 90 degrees. The diffraction efficiency of both S and P polarizations at any angle is dependent on the product of thickness and index modulation while the angle inside the medium is dependent on n. We investigated predicted conditions where only one polarization would be diffracted and subsequently proved n varies from about 1.4 to 1.2 after processing and depends on the film thickness and processing procedures. Transmission gratings made at angles from 36 to 66 degrees were fit to mathematical models as proof of the phenomena,some performed with extinction ratios greater than 100:1. We were also able to demonstrate a similar range in conformal reflection structures and to design a novel polarizer. The calculation of exposure geometries for display holograms becomes more accurate when index change is included in the formulas but some results remain hard to explain. ==REDISCOVERY OF A LOW INDEX== Several years ago we had verified by modeling notch filters that Shankoff was correct in claiming that dichromated gelatin could have an index modulation, delta n, of as much as .26. In 1977 Meyerhofer argued that this may imply that the bulk index, n, could drop as low as 1.27 and that the large delta n and corresponding low n was the result of forming small distributed voids of air in the gelatin. He offered no proof or experimental evidence of the low value and made no comments pertaining to the implications and as far as we know it has been overlooked and undervalued ever since then. We were made aware of Meyerhofer's conclusions and publication, which was on my bookshelf for 10 years, only after we had tabulated hundreds of data points that appeared to support values of n as low as 1.2. We were attempting to make a polarization splitter at an angle that should have worked if the n were near 1.5, in desperation we tried incremental angles above and below the calculated angle. We made hundreds of gratings and carefully plotted the S and P efficiencies as a function of delta n in the region where the S first goes to zero. The design we were concentrating on depended on an internal diffraction angle of 30 degrees, which of course depended strongly on n for a grating structure with fringes normal to the surface. The experimental data we gathered is shown graphically in figure 1. SPIE vol 1667, San Jose, CA. Feb 13 (1992)<br> [[File:pg15.gif|center|Figure 1]] '''Figure. 1.''' Efficiency of S and P as a function of delta n for angles between 36 and 50 degrees, experimental results in 7 micron films, P curve sections are drawn over a common minimum S value. ===Transmission proofs of a low effective n=== The data we had in hand indicated by modeling on a mathcad template that the index was around 1.26 and we eventually modeled 4 other configurations that could be used to demonstrate a low n or measure it more closely. Each model was derived from Kogelnik's one dimensional coupled wave model of either transmission or reflection gratings. Figure 2 is the model that best matched to the first experimental data in figure 1, the thin lines are computed plots and the heavy sections indicate where supporting data was obtained by making and testing at 38 degrees until both crossing points were found. The crossing points had to be nearly equal for further evidence of being at the right angle. Figure 3 is a simple proof where the internal angle will be 90 degrees and no P can be diffracted at any value of delta n. This proof has a catch to it because the value of n varies with the value of delta n so some p light actually will be diffracted at low values of delta n where n is still high. The range of delta n we tested pushed n low enough to nearly zero out the P light as S went through 2 maxima at 64 degrees external. Figure 4 is an accidental proof that we modeled after the fact as we reached modulation saturation while testing at 48 degrees. At an external angle of 48 degrees we made a few gratings that diffracted virtually all of both polarizations which models to an n of about 1.27. Some of the data points in figures 2 thru 4 were taken from 7 micron films and also in 5 micron films which because of gradients behave more like 4 micron films. The positions of maxima and minima remained the same for both films. [[File:pg16-1.gif|center|Figure 2]] '''Figure 2.''' Computed model with overlay of normalized experimental data points taken from 35 samples. [[File:pg16-2.gif|center|Figure 3]] '''Figure 3.''' Computed model for 90 degree turn internally with some data points normalized and overlaid. [[File:pg16-3.gif|center|Figure 4]] '''Figure 4.''' Computed model matching experimental results of S and P both near 100% in 2 or 3 samples. ===Reflection proofs of a low n in DCG=== Figure 5 shows what turned out to be the most conclusive and easiest to demonstrate proof. Conformal reflectors have an angular spectral bandwidth that varies widely with n. The first plot shows this dispersion curve for n = 1.54 and a zone where we actually measured various reflectors that had values of n ranging from 1.4 to 1.27. The small straight horizontal line is the locus of external incident angles where no P light is reflected and runs from 64 to about 85 degrees. [[File:pg17-1.gif|center|Figure 5]] '''Figure 5.''' Computed angular dispersion curves for conformal reflectors with bulk n ranging from 1.54 to 1.27 overlaid with measured data. [[File:pg17-2.gif|center|Figure 6]] '''Reflection: Internal angles remain constant''' '''Figure 6.''' Graphical representation of the behavior of a reflector if original exposure conditions prevailed and below it the behavior due to low n and expansion of the film. Figure 6 illustrates graphically what occurs at an n of 1.27 and what would have to occur at any n above 1.41 where total internal reflection would result whenever internal angles reached 90 degrees. A reflector that worked at 650 nm at normal incidence was made and tested with a laser source at 458nm for reflected components around the predicted input angle of 64 degrees and the minimum P was found near 64 while S was almost all reflected. Other samples were made and tried in a similar fashion and we found that broadband processed thin films fit the lower dispersion curve and thick narrow band films fit the curve corresponding to an n of about 1.4. The dispersion was particularly easy to measure and this final proof also led to some novel flat plate polarizer designs. ===Evidence of a gradient in n=== One of our most used film formulae produces an unexposed thickness of 5 microns, an exposed and processed thickness of 5 microns and a processed but collapsed thickness of 3.5 microns. The mixture is 25% sensitizer, most of which is removed during processing, and these measurements make sense but the diffraction properties are a little difficult to explain. A conformal reflector recorded at 514nm and normal incidence reflects at a center lambda of 580 nm and a bandwidth of 50 nm. It has a weak reflection band extending to about 450 nm and by measuring the dispersion and polarizer angle we know it has an average n of 1.4. If it were uniform and if air replaced the dissolved solids it would have to measure 1.23 times thicker, (over 6 microns),than it actually is to reflect yellow light. It also would not reflect blue light unless some portion of it actually became thinner by about the same amount. This observation leads us to propose that the microstructure actually has a region of net shrinkage with a corresponding high n and low delta n near its glass interface and a region of net expansion of up to 1.5 times and a corresponding low n and very high delta n. From prior work in modeling chirped and graded reflectors we think this is a reasonable conclusion, the only new observation is a probable and reasonable gradient in n. The before and after structures are shown in figure 7. [[File:pg18.gif|center|Figure 7]] '''Bragg plane spacing before and after processing''' '''Figure 7.''' A graphical view of the probable micro structure of a 5 micron thick chirped DCG reflector based on its optical properties. ==IMPLICATIONS OF A LOW N IN DCG DEVICES== The list of problems and advantages of the low n is long and curious. The first advantage we noted was that the original polarization splitters we were working on could now function at 36 or 38 degrees instead of the 53 degrees we originally calculated to be necessary. Fresnel reflections are lower and cross sections are higher at 36 than they are at 53 and everyone is happier. Some other consequences, advantages and design considerations are enumerated below. ===Holographic scanners=== The design of "hologons" in DCG sometimes includes consideration of efficiencies in both P and S polarizations. In general as the angles get larger the combined efficiencies go down, except for a few special angles where delta n * T products can catch S and P both at their peaks if carefully controlled. The designs are usually made with an assumed n of 1.5 to 1.56 and measured efficiencies are usually lower than expected because the final n is really less than 1.4. The full internal angles have become larger than the original exposure angles driving P downward. In designs with slanted fringes, the Bragg condition can rarely be satisfied at the construction input angles after processing. The Bragg error appears to come from a net change in film thickness which tilts the fringes up a little so new compensating exposure angles are calculated to compensate. This correction inadvertently also corrects for the change in n which manifests itself exactly the same as a standing up fringe, closer examination would show that the processed film may have expanded by 10% or less but the correction that was finally necessary was calculated for an apparent expansion of 30%. The excess correction is for the lower value of n. Figure 8 illustrates the effects of expansion alone and then for combined expansion and decreased n in a slanted grating at 633nm. The lower n alters the effective spatial frequency in tilted structures by making the optical path shorter and causing diffraction at a larger full internal angle. The correction for n is essentially an over correction for tilt. In the example the final fringe tilt will be 5 degrees higher than the tilt required in an unchanging n material. Corrections are made and shown for exposure at 488nm. [[File:pg19.gif|center|Figure 8]] '''Figure 8.''' Highly slanted grating with corrections for a shorter wavelength, expanded film and lowered n. ===Holographic zone plates=== An optic with a varying spatial frequency and a varying fringe tilt angle will reconstruct with aberrations if the n changes between construction and reconstruction. An on axis zone plate producing an f/2 cone of light will have an effective increase of spatial frequency in the radial direction so that at the outer edges the diffraction angle could be off as much as .5 mrad. The focal length gets shorter the further off axis the light gets for zone plates requiring collimated inputs and focusing outputs. This is equivalent to a plano-convex lens except that the spherical aberration is in proportion to the net change in n. This implies that if the exposure is made with a plano convex lens instead of a pinhole then the spot size on reconstruction will more closely meet diffraction limited dimensions. Very low f# optics will have problems closer to those in figure 8 and are very difficult to make with precision and correct fringe tilt. If the zone plate is designed without slanted fringes, the equivalent of a double convex lens, then it will not be affected by a change in n. This is in contrast to the refractive equivalent which has considerable spherical aberration. Fringes formed without tilt always diffract at the same external angles no matter what n changes to. Multiple exposure gratings with small tilts and rotations have to be designed with a consideration for a change in n even if no compensation is made for expansion. The change in n usually dominates as a cause for playback errors in any transmission optic that has a tilt in the fringes. ===Multicolor reflection holograms=== A two color reflection hologram can be made with two color exposures and if n and T remain constant then playback will be at the same angles and colors. A good DCG film mixture for two color holograms is 12 microns thick before exposure and 14 to 15 microns thick after exposure and has an initial 6% solid sensitizer concentration. The film expands by a factor of 1.3 causing n to drop to 1.4, resulting in reconstruction at longer wavelengths and different angles. An example of a 2 color design is given to illustrate the relative magnitudes of the changes and the corrections to compensate for them. If we wish to reconstruct at 560nm and 620 nm with a white light incident at 45 degrees, then we must expose at 60 degrees with 458nm and at 51 degrees with 514nm laser light. We should change the input recording angle by 9 degrees between exposures to correct for the change in n and T. In the reflection geometry the bulk of the correction is for the expansion rather than the drop in n. The reflective geometry magnifies fringe tilt errors more than the transmission geometry. The lower n result in an increase in the angular dispersion so that in general DCG refection holograms change color over a wider range with equal tilt than equivalent silver grain reflection holograms which have a higher average n. ===Powered reflectors=== We have produced near on axis reflectors of about f/7 that were constructed and reconstructed at 488 but had enormous aberrations. The focal length was observed to vary by over 2% from center to edge of these reflectors. We always had reasoned that if the reconstruction wavelength were identical to the construction wavelength then the aberrations had to be present in the construction optics if they were observed in the reconstruction. This is clearly not the case for any structure with tilted fringes and a changing n. We had assumed that because the reconstruction was at the same wavelength that no fringes could be distorted because the fringe placement must be identical to the construction geometry. The correct reconstruction color is the result of the film expanding while the index is dropping. The effect of tilted fringes for the reflection case is similar to the transmission case. The effective playback spatial frequency is decreased, the fringes are tilted up a little, the internal angles are the same but the lower n decreases the exit angle giving the optic an increasingly longer focal length as light moves radially outward. Since this is a variable effect the correction can only be iterative and again may be approached by using oppositely aberrated construction waves rather than near perfect spherical waves from pinholes. Construction waves of different curvature may also be used to correct the aberrations in the same fashion that is done to correct for a wavelength shift from construction to reconstruction. ===Reflective polarizers and notch filters=== Notch filters of high density and low n exhibit angular dispersions that span the visible spectrum. One size fits all, we have examples that reflect 650nm at normal incidence and 400 nm at 85 degrees. In fact as mentioned earlier, this dispersion is one of the most convincing proofs of a low average n in these structures. The range of useful polarization separation angles actually runs from about Brewster's angle to 85 degrees in a simple conformal geometry as shown in figure 9. This design is easy to build and easy to make broadband through processing tricks and multiple exposures. Conformal reflectors are the unique case where the diffraction angle for all colors can be the same and the angle for zero reflection of P light is also the same at all reflected wavelengths. A second more complex and untested design is shown in figure 10. It will have some of the properties of a transmission hologram and will not have a very broad bandwidth and will be very difficult to make correctly. The only reason for even doing so is that it may be used close to on axis in a flatter package for illumination of LCD panels and other devices requiring polarized light. [[File:pg21.gif|center|Figure 9]] ''White Light Polarizer'' '''Figure 9.''' A simple to make white light polarizer or polarization separator with proven performance. [[File:polar.gif|center|Polarizer]] ''Polarizer With Tilted Fringes'' '''Figure 10.''' A much more difficult to make polarizer with somewhat unknown and untested properties but near on axis operation. The practical angles and bandwidths are unknown. ==EVALUATION AND CONCLUSIONS== We have illustrated by example and mathematical modelling that DCG always reconstructs with a lower n than it has at the time of exposure. We call this an aerogel effect because it is accomplished with similar procedures to those used in making glass aerogels and exhibits similar properties. Unexposed processed plates of gelatin also expand by as much as 50% and must also exhibit properties of a lower n. Wetted and dried processed plates revert to a higher n and corresponding smaller thickness. A curious side issue is that researchers measuring n with brewster angle methods or index matching methods do not get the low n values that we have observed and demonstrated. These methods measure n at 1 surface only and as we have observed the n may vary widely through the volume. At least one group at Kaiser Optical has published bulk n measurements as low as 1.34 in the past year and others are studying the gradients in n.We have measured the average "effective" bulk n in periodic structures and found that it is important to the design of precision DCG optics of all kinds. Several diffuse object holograms were also tested for a low n and they also exhibit the polarization sensitivity and angular dispersion found in notch filters. We have included these effects in our design software and have found that the model more closely resembles the product, an inclusion of the gradient in the value of n and a curve in the fringes in our modelling would make it even more precise. We will likely pursue these improvements in the future in order to further reduce the surprises we often get. ==REFERENCES== * H. Kogelnik, "Coupled wave theory for thick hologram gratings" Bell Syst Tech J. vol 48, p2909-47 (1969) * R. D. Rallison, "Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug.(1987) * T. A. Shankoff, "Phase holograms in dichromated gelatin" Appl. Opt. 7, p2101-50 (1968) * D. Meyerhofer, "Dichromated Gelatin" Springer-Verlag, Holographic Recording Materials vol 20, chapt.3 p84 (1977) * L. D. Dickson, private communication during 1991. * R. D. Rallison "Survey of properties of volume holographic materials", SPIE vol. 1051, Practical Holography III, p. 68 - LA, CA.(1989) * F. T. S. Yu. "Effect of Emulsion Thickness Variations on Wavefront Reconstruction". bibliog diags Ap Optics 10:1324-8 Je (1971) * R. D. Rallison "Incoherent Multifocus Hololens design and fabrication", SPIE vol. 1183 International Conference on Holography, Optical Recording and Processing of information, Varna, Bulgaria.(1989) * M. Chang and N. George, "Holographic Dielectric Grating; Theory and Practice" bibliog diags Ap Optics 9:713-19 Mr (1970) * R. Kostuk, University of Arizona, Private communications (1991) * J. L. Salter and M. F. Loeffler, "Comparison of dichromated gelatin an dupont HRF-700 photopolymer as media for holographic notch filters".SPIE vol 1555, jul (1991) ''Last modified on 6/10/99'' [[Category:Rallison]] fdf835a400f24851a077f9c6cdf168984e8e5222 0 841 1773 1772 2013-05-12T04:08:16Z Jsfisher 1 1 revision wikitext text/x-wiki # "Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)." S.P.I.E. Proceedings, Volume 212, pp.22, 1979 # "Hologram Scanner Design and Fabrication in Dichromated Gelatin (DCG)." S.P.I.E. August, 1982,San Diego # "Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College Holography Workshop and First International Symposium on Display Holography, July 1982. Lake Forest, IL. # "Characteristics of Dichromated Gelatin (DCG) Scanners for Printing Applications" SPIE August, 1984, Vol 498, pp.199. # "Applications of Holographic Optical Elements" Lasers and applications, December 1984, p. 61 # "Pulse Portraits, The Holochrome Process" S.P.I.E., January 1985, Vol 523-01. # "Holographic Optical Elements (HOES) in Dichromated Gelatin (DCG)" S.P.I.E. January 1985, vol 523 p. 40 # "Practical Polymers for Holography", Second International Symposium on Display Holography, Lake Forest College, IL. # "Holographic Scanners for Machine Vision, Printing, and Bar Code Applications." S.P.I.E. January 87, Vol. 747 # "Transmission Holograms for HUDS" SBIR 86.1 Final Report, Wright Paterson AFB, April 1987 # "Cascaded Transmission Holograms for Head-Up Displays" SPIE Vol 883 Holographic Optics, 1988 # "Alternative Volume Recording Media, A Qualitative Comparison" Third International Symposium on Display Holography, Lake Forest College, IL 1988 # "Survey of properties of volume holographic materials", SPIE vol.1051, Practical Holography III, 1989 p.68 LA,CA # "Incoherent Multifocus Hololens design an fabrication", SPIE vol.1183 International Conf. on Holography, Varna, Bulgaria. # "Novel Enhancement of Photopolymers", SPIE vol 1212, Practical Holography IV, 1990, LA, CA. # "Combat Vehicle Stereo HMD", SPIE vol 1456, Helmet Mounted Displays, 1991, San Jose, CA. # "Control of DCG and nonsilver holographic materials" <a name="SPIE1600">SPIE vol 1600</a>, International symposium on Display Holography. # [[Polarization properties of gelatin holograms|"Polarization properties of gelatin holograms"]] SPIE vol 1667, Practical Holography VI, 1992, San Jose, CA. # "Using Thick DCG, 30 to 100 microns" SPIE vol 1914, Practical Holography VII, 1993, San Jose CA. # "Brightness increase in an LCD stereo display" SPIE vol 2176, Practical Holography VIII, 1994, p 241, San Jose CA. # "Holographic Polarization-Separation Elements" Ap. Opt. vol 33, No 23, p. 5378-5385, 10 Aug 1994. # "Wavelength Compensation by Time Reverse Ray Tracing" SPIE vol 2404, p. 217 Diffractive and Holographic Optics and Technology II, San Jose CA, Feb 1995. # [[Wavelength compensation at 1.064µ using hybrid optics|"Wavelength compensation at 1.064 microns using hybrid optics"]], SPIE vol 2689, Diffractive and Holographic Optics Technology III, San Jose CA, Feb 1996 # "Dichromated Polyvinyl alcohol (DC-PVA) wet processed for high index modulation" SPIE vol 3011, Practical Holography XI and Holographic Materials III, San Jose, CA, Feb 1997. # [[Recording Material Selection|"Matching a phase material to an Application"]], Journal of Imaging Science and Technology, vol 41, No 3, 1997 # "Fractured zone plates for spatial separation of frequencies" SPIE vol 3633, Diffractive and Holographic Elements, San Jose, CA, Jan 1999 #"Diffractive Optics replicated in Amorphous IR Glasses" OSA Technical Digest vol 10 Diffractive Optics and Micro-Optics, Jun 8-11, 1998 Kona Surf Hotel, Kailua-Kona, Hawaii # "Large Aperture Scanning Lidar Optics" Final Report for NASA contract NAS5-99192, 20 Nov 1999 # [[History of Dichromates#Serendipity|"Dichromates come from Jello"]], SPIE vol 3956, Practical Holography XIV, San Jose CA, Jan 2000. # [[Media:Zone-SPIE2001.pdf|"Hoe Enhanced 355 nm Multichannel Direct Detection Lidar"]], SPIE vol 4291, Diffractive and Holographic Technologies for Integrated Photonic Systems, San Jose, CA, Jan 2001. # [[Media:FAB_VPHG_spie2002.pdf|Fabrication and testing of large area VPH gratings]], Rallison, Richard D.; Rallison, Robert W.; Dickson, LeRoy D. SPIE vol 4842, Specialized Optical Developments in Astronomy, pp. 10-21 (2003) ''Last modified on 1/14/01'' [[Category:Rallison]] dc70cf0285ce4716aeca58cb64c3326fed22aa17 0 842 1775 1774 2013-05-12T04:08:17Z Jsfisher 1 1 revision wikitext text/x-wiki [[File:rallogo.gif|center]] [[About Ralcon Development Labs]] ==Design and Fabrication of HOEs, DOEs and Hybrid optical systems.<br>Specialists in Volume Holographic Optics (VHOEs) since 1974.== If you do not find the information you are after, try the [[Complete Site Map]]., send an email, or [[Contact Information, Facilities, Materials, and Ordering Information#contact|contact]] someone directly. {| border=1 |- | '''Information about Ralcon''' || '''Ordering Information''' || '''Papers and Publications''' |- | * [[About Ralcon Development Labs]] * [[Instructions for Getting Here|How to get here]] * [[Resume of Richard D. Rallison|Experience]] * [[Ralcon Development Lab|Facilities]] * [[Ralcon Development Lab#Materials|Materials]] * [[Instructions for Getting Here|How to Get Here]] * [[Ralcon Development Lab#Contact|Contact Information]] * [[Ralcon development Lab#Ordering|Ordering Information]] * [[Holotool Contents|Get Holotools here]] | * [[HOE Tutorial|Tutorial]] * [[Circle To Point Converters|Circle To Point Converters]] * [[HOE Kit|HOE Kit Information]] * [[2 and 3 Color Dichromates|Pseudo-color Techniques]] * [[Hoes and Does|HOES and DOES]] * [[VHOE Relationships|VHOE Relationships]] * [[Zone Plate Equations|Zone Plate Equations]] * [[Links|Links]] | * [[Publications|Publications]] * [[Fringe Locking|Fringe Locking]] * [[Recording Material Selection|Recording Material Selection]] * [[Stability Issues in DCG|Stability]] * [[History of Dichromates|History of Dichromates]] * [[Bibliography|Bibliography]] * [[History of Dichromates: DCG References|DCG Specific Bibliography]] * [[Media:DWDM-Dickson_grating_white_paper.pdf|Dickson Grating White Paper]] {392kB) |} '''For all inquiries and orders, please contact http://www.wasatchphotonics.com.''' [[File:wplogo_new_small.gif|center|Wasatch Photonics]] * [[What's Happening|What's New?]] (includes Employment Opportunities) * [[Changelog for Ralcon Development Lab web page|What's New on this Web Page?]] Please email comments about content to rdr@ralcon.com. This page hosted by Xmission. [[File:xmicon.gif]] [[Category:Rallison]] 9fbe73f408d1f734dacae9eb37c19a4873c16f7c 0 843 1777 1776 2013-05-12T04:08:17Z Jsfisher 1 1 revision wikitext text/x-wiki == Education == *Engineering Studies, Utah State University, 1964-1968 *B.S.E.E., University of Utah, 1969-1973 (Cum Laude) *M.S.E.E. Laser Systems, U.S.C. 1974-75 (not completed) *Ph.D. Electro Optical Engineering, Honorary, USU 1995 == Experience and prior work == Approximately 35 years of professional or technical grade experience. Has been engaged in development work of CO2 Waveguide, Co-Axial Cadmium, Doubled "blue" Yag and Dye lasers at Hughes Aircraft for space communications, countermeasures and underwater communications. Performed ION laser design upgrades at American Laser Corp. and fabricated a novel multiple pass Ruby laser system for Dikrotek. Experienced with diode lasers including fabrication of a small bar code scanner for that coupled a diode laser, grin rod and focusing holographic scanner together. Another device developed and co patented with IBM splits diode laser light into polarized components and replaces a Wollaston prism. An early commercial success for IBM was the development of holographic scanner fabrication methods in 1979, followed by many years of development in Holographic elements, devices and systems and sales of Holographic Optical Element (HOE) fabrication technology to IBM, Pilkington (UK), Holosonics, Seimens, Raven Holographics in England, Portson Inc of Kansas., APA Optics of MN, Northrop corp of CA., Metrologic Instruments of NJ, Process Instruments of SLC, Bell Resources in Australia and Terabeam of Seattle. Work for NASA beginning in 1990 to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have begun. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s. Many spectrographic optical designs, head mounted display designs and some holographic memory designs have been made and brass-boarded. Some have become commercial products. Mr. Rallison has served as a consultant in Diffractive Optics for dozens of companies and has given numerous lectures on holography at the University of Utah, USU and Lake forest College as well as occasional invitations to give paid tutorials in industry. Other work includes the design and fabrication of novel HUD optics for the Air Force on an SBIR grant and an investigation of new holographic recording polymers for the Army NVL on an SBIR contracts. Contracts have been successfully completed for the army at Aberdeen where 5 HMDs were designed fabricated and delivered. Work for VIO in Seattle involved design and fabrication of Stereo Color HMDs or their components. 10 years of work on NASA contracts to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have been attempted. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s such as telecom receivers for free space interconnects developed for another Seattle company named Terabeam, co-founded by RD Rallison. He has fabricated multi lens arrays, gratings, HUDs, notch filters, Fourier filters, scanners, co-phasal multiplexed gratings, spectrophotometer gratings and filters, reflectors, diffusers, depixelators and assorted other HOEs. He owned and operated a company that produced millions of high quality display holograms for commercial use over a 10-year period. He worked as a Video Engineer and Cameraman for a CBS affiliate and prior to that performed work related to weather modification at the Utah Water Research Lab while also producing commercial light shows and devices for entertainment type productions. == Position at Ralcon == Ralcon Corp. is a vehicle for Mr. Rallison to consult in Optics and develop products. He owns an 8000 square foot facility in Paradise, Utah where laser and Holographic Optics development work has been going on since 1985.The facility is equipped with Argon, Yag, Dye, Nitrogen, HeNe, Ruby and various Diode lasers. Four floating stable tables of various sizes in well insulated rooms provide the basic optical beds and each has its own Argon, HeNe and YAG laser. A machine shop with a variety of glass shaping and polishing machinery compliment the holographic optical fabrication facility. Ralcon Development Lab (RDL) ceased commercial business in June of 2004 at the request the Cache County planning and zoning commission. Commercial customers of RDL have been referred to Wasatch Photonics in Logan UT, which was created in part to continue the work of RDL. Work at RDL is limited to research for NASA GSFC and other government labs. == Professional Affiliations == *Institute of Electrical and Electronic Engineers *Sigma Tau (Honorary Society) *Society of Photo Optical and Instrumentation Engineers(SPIE) *Optical Society of America (OSA) *Aircraft Owners and Pilots association (AOPA) == Licenses == *First Class Radio Telephone *Private Pilot, SEL, RH, Glider, Hang Glider *CDL -class A-air-trailer == Patents == * #4,913,990 "method of tuning a volume phase hologram" * #5,303,085 and #5,619,377 "Optically corrected helmet mounted display" * #4,950,067 "optical system that helps reduce eye strain" * #5,291,316 "Information display system having Transparent Holographic Optical Element" * #5,602,657 "Hologram system having hologram layers with rotationally offset Bragg planes" * #5,519,517 "Method and apparatus for holographically record and reproduce images in a sequential manner" * #6,097,543 "Personal Visual Display" * #5,991,087 "Non-orthogonal plate in a virtual reality or heads up display" * #5,991,085 "Head mounted personal visual display apparatus with image generator and holder" * #5,949,583 "Head mounted display with image generator, fold mirror and mirror for transmission to the eye position of the user" * #5,945,967 "speckle depixelator" * #5,903,396 "Intensified visual display" * #5,903,395 "Personal visual display system" * #5,864,326 "Depixelated visual display" * #5,751,425 "Raman spectroscopy apparatus and a method for continuous chemical analysis of fluid streams" * #6,100,975 "Raman spectroscopy apparatus and method using external cavity laser for continuous chemical analysis of sample streams" * #5,673,151 "Image correction in virtual reality and heads up displays" * #5,642,227 " Optical correction for virtual reality and heads up displays" * #6,678,079 “Transceiver for a wireless optical telecommunication system “ * #6,608,708"System and method for using a holographic optical element in a wireless telecommunication system receiver” * #6,369,952 “Head-mounted personal visual display apparatus with image generator and holder” * #6,160,666 "Personal visual display system” == Awards == *Dept of Defense SBIR Quality Award == Publications == Follow &lt;a href="/web/20080514140659/http://www.xmission.com/~ralcon/publications.html"&gt;this&lt;/a&gt; link to see our publications list, including links to online versions when available. [[Category:People]] [[Category:Rallison]] 04a18739831ba26439bdc17b4a537e3653119c1a 0 844 1779 1778 2013-05-12T04:08:17Z Jsfisher 1 1 revision wikitext text/x-wiki == Refrigeration == DCG stores well at low humidity in a refrigerator or freezer but containers must prevent contamination, condensation, freezer burn and frost which can all destroy surface quality. Film of 10 to 20 microns or more store best and are good for at least a year. At room temperature and 50% RH, thin films are good for a few hours, thick films typically last a week or more. The addition of a small quantity of TMG to the mixture will greatly increase storage time at room temperature by increasing the pH. == Light bulb as an alternative to the fixer == Developing is simply a process of reducing the remaining chromate ions and thereby uniformly hardening the gelatin. Too much hardening will give a clean, clear but weak and green result. Too little hardening will leave the hologram milky and weak and reddish or yellowish. Development is done either optically or chemically using fluorescent or incandescent lamps or any suitable reducing agent or tanning solution. [Rallison used either Kodak fixer or a 100W lamp at 6 inches from the hologram, for time periods of between 5 and 15 seconds. But he was also exposing at 441nm which would do a much better job than 532nm. By the way, I use the light bulb immediately after the dark reaction (before swelling with any water). I've used Knox gelatin with exposure at 457nm, and this is usually hard enough by itself to require neither fixer nor light bulb.] == Film codes == The film mixtures vary in dichromate and gelatin percentages. The variations depend on the specific use that a DCG film plate has. The film code currently used contains three numbers. The first being the gram-weight of the ammonium dichromate, the second being the gram-weight of the gelatin, and the third being the gram-weight (mis) of the water to be used in the film mixture. (Usually mixed in a 500 ml poly bottle.) The code for film used in broadband image holograms is 8-30-350. Thus, 8 grams dichromate, 30 grams gelatin, and 350 grams (ml) of water are mixed together. The mixture code for "red" holograms is 3-30-200. Most holographic optics are made in 10-30-250 to 8-30-150. In using the film code for a variety of mixtures, the 30-gram gelatin weight number always remains constant. Thus, when a thicker emulsion is desired, the water number decreases. And when more absorption is desired, the dichromate number increases, an increase in thickness narrows the bandwidth and an increase in dichromate shifts the color toward the blue. As a general rule, thicker emulsions require longer process times but are easier to make uniform. The dichromate concentration determines light absorption and the center reconstruction wavelength of the hologram. For higher dichromate concentrations, the increased absorption produces larger gradients of index modulation. Lower the dichromate concentrations produce more uniform index modulations. Larger gradients yield slightly larger bandwidths and the removal of higher percentages of dichromate during processing results in thinner and thus bluer holograms. When a specific bandwidth is desired, along with a specific reconstruction wavelength; it is best to experiment with various film mixtures. Usually starting with a standard mixture and then adjusting the thickness, and dichromate content to achieve the desired results. The color controllability and uniformity of DCG film improves with thicker film emulsions. Consequently, they are more forgiving in their exposing and developing parameters. Extremely thick (25 micron) emulsions (X-30-150, a 5 to 1 water-to-gel ratio) are difficult to use. They are prone to excess bubbles, premature jelling, film pits, low viscous flow, increased impurities and during processing sometimes pull up off the substrate. == Ageing and thickness == The film is ready for exposure after it has been aged an hour or so for a 350 mixture or a day later for a 150 mixture. The addition of 1 or 2 ml of TMG will extend the useful room temp life of 350 film to a day or two and will make 150 film last for several weeks in a 21 degree C, 50% RH environment. The thicknesses of the commonly used mixtures after spinning at 80 RPM and after processing are as follows: 350 yields 5-6 microns, 250 yields 8-9 microns, 200 yields 10-12 microns, 150 yields 20-24 microns. == Bandwidths and color == The relative bandwidths run from 50 to 150 nm for 350 film, depending on processing used. 250 and 200 film make 10 to 50 nm bandwidths depending on processing and 150 film can get down to 8 nm but also runs as high as 30 nm. The color of a film made from a 3-30-200 mixture is around 630 nm when shot at 514 nm. The color of 6-30 film is around 590 for a 514 shot and a 10-30 mixture will easily be tuned to play back at the same wavelength it was shot at. [[Category:Rallison]] [[Category:DCG]] 80c9e16ea493e759b84c865af46a199cd458c2a5 0 845 1781 1780 2013-05-12T04:08:18Z Jsfisher 1 1 revision wikitext text/x-wiki =Phase materials for HOE applications= Richard D. Rallison<br>Ralcon Development Lab, Box 142, Paradise UT, 84328<br>ph (435) 245 4623, fax 6672, e/mail rdr@ralcon.com The choice of a phase recording material strongly affects the utility of the final recording. For display holograms properties like brightness, contrast, color range and color saturation might dominate and the choices are part art and part science. For HOEs, the extended range of properties that may require manipulation and the choices of materials to obtain each property in the required quantity, makes a working knowledge of what can be done extremely useful. This paper presents the fundamental properties of phase recordings and the fundamental properties of many phase materials so that a choice that will get a person from plan to product can be more readily made. Recipes are not given but references to recipes are and modifications or procedures that can modify a well known material may be described. The object of this paper is to make the reader aware of both the strong functions of these materials and the weak or subtle properties so that a design may be reviewed for feasibility a little more thoroughly and hopefully the route to a functioning product will be shorter and less costly. ==Introduction== The phase recordings we will consider are the simple transmissive sinusoidal volume plane grating, the powered or focusing volume grating, the general reflective volume grating with the two special cases of a conformal reflection recording and a strong spherical wave recording and finally the large class of surface phase gratings so popular because of the supposed ease of fabrication. We first identify as many of the properties of these phase structures as we can, then discuss the variations and mix of these properties that may be required in a well functioning final copy. At this point we define the minimum performance required of the end product and then list some popular media to choose from. In order to make a good first choice we need to know the intrinsic properties of these materials and their limitations, strong and weak points, cost, availability and perhaps what would be termed their "nuisance factor". This last factor is the reason I end up with plenty of work to keep me busy. Very often the art gets in the way of the science, the recipe has too many variables, the learning curve is a little too long and the literature a little too short and probably ambiguous and contradictory. We will use unscaled illustrations as much as possible and keep things as simple as possible, steering clear of any exhaustive validations of claims made for different materials or the chemistry involved. The reference material can be used to satisfy these other needs. Only simple algebraic equations or approximations are used without formal justification. ==Basic phase diffracting structures== Each of the figures 1 through 5 represent a common spatial phase modulator. The simple plane grating covers a wide terrain, wide enough to include transmissive display holograms made in bleached silver grain films which can be thought of as being made up of very many superposed plane gratings or as many tiny spatially multiplexed gratings. The reflective grating covers just about everything else that could be made but we have to consider the subtleties of various configurations and some special cases. Surface phase gratings are not just thin volume gratings, they have become a large class of optics themselves, referred to as diffractive optics (DOEs) and they enjoy considerable popularity at the present time. Some materials in common use today can be used to fabricate all of these diffraction structures, but none will cover all possible constructions within every class. Within the description of the properties of the HOE that is to be fabricated is the description of the material that will have to exist to make it. In most cases the material does exist and may be available in some form, but not always on the right substrate and in the right thickness. In real materials the direction that light transits through the HOE makes a difference, sometimes a large difference, the efficiency of a grating can actually be greater in one direction because of gradients in the modulation and holographic mirrors often reflect different spectra on each side with different intensities. ===Basic transmissive volume holographic gratings.=== Fig 1. Depicts an edge view of a section of a plane grating of thickness (T) of fringe spacing (d), at the surface and of fringe tilt or Brag tilt (B). The fringes themselves are regions of hi and low index (n) with the differences referred to as (Δn). The product of ΔnT is the total modulation of the grating but the diffracted light in each order also depends on angles a and b and wavelength (λ) which together define d. The change in index is usually not uniform through the film. It is common wisdom that the thicker the grating, the narrower is the angular bandwidth and the better is the suppression of higher orders, if they can exist. The other half of that assumption is that the value of Δn is small enough to make the product of ΔnT just large enough to diffract all of the light. If in fact the product is 2 or 3 times that high, the grating will behave as a 3 or 4 times thinner grating. Materials that require wet processing almost always have a gradient in index that can be very high, further reducing the effective thickness of the grating. Even real time recording materials, including photorefractive crystals have a gradient in index from absorption and behave as if they were much thinner than they are. The power lost to higher orders is proportional to Δn² so if modulation is excessive then not only is a thick grating rendered thin but it may diffract most of the incident power into useless orders. Another gotcha in dealing with thick gratings is the wandering Brag tilt B. Whenever wet processing is used there is a high probability that the original tilt made during exposure will play back at some other angle. In very thick gratings this error can exceed the angular bandwidth of the grating and render a non uniform grating that is useless. Thick gratings made in low shrinkage photopolymers and photocrosslinkers that require no processing seem to work well enough. If the intended use of the grating requires a thin structure with a broad angular and spectral response then the angles must be chosen so that higher orders cannot exist. This can begin when a and b both equal 30 degrees and the 2nd order becomes evanescent at 90 degrees (in air). The -1 order may still exist but is not entitled to receive much power at modulation levels near optimum for 99% diffraction efficiency (DE). When any of these gratings show excessive B error there is usually a preexposure fix that can be done to compensate or a post processing bake down or swell up for each material. A special case of this grating is the total internal reflection (TIR) geometry that requires extreme control over fringe tilt error. It should also be remembered that TIR gratings will not diffract P polarized light very well or at all for the same reason that Brewster's angle works. [[File:phasefig1.gif|Figure 1 Image]] '''Figure 1.''' The simple plane volume phase grating with properties: # sin a + sin b = λ/d # DE is proportional to sin²(ΔnT) and to 1/λ cos a + cos b) # Power lost to higher orders is proportional to Δn² # Fringe or Brag tilt B is proportional to T and n Figure 2 shows a common variance on a plane grating, a grating with a spatially varying spatial frequency such that rays of a certain λ and a common input direction will be diffracted to a common point on the output side. We may have seen this in text books as an off axis equivalent lens which is generally assumed to be a practical application of holography. For the fast optic shown, the output could be a family of points, half of them virtual and half real and all related geometrically to the fundamental focal length. Note that from top to bottom the spatial frequency (f₀ = 1/d) varies from very low, perhaps 200 l/mm to very high, perhaps 2000 l/mm. In the plane grating we only had to consider the modulation product of nT but now we have to add the term f₀ which also modifies DE. Note also that higher orders are nearly impossible to suppress at the top of this HOE and are nonexistent at the bottom. How would you ever make this design work? What material could be used? The difference in spatial frequencies could be compensated for in most materials by adjusting exposure energies in some way so that the lower end received less exposure and so create lower modulation than the top. This would solve the modulation balance except that now even more energy will be lost in the higher orders for only a small gain in the +1 because the losses at the top are proportional Δn², which just went up. Then perhaps the better fix is to try to keep n constant and vary the T from top to bottom such that the product of ΔnTf₀ is everywhere the same. Obviously you cannot buy such a material commercially so this special coating is very experimental. The processing will also have to be tailored because it is not likely that the thicker portions can be processed in the same time frames as the thinner portions. What about real time materials that saturate? Perhaps if available in liquid form, this HOE could be made. As the f# goes to 2.5 or higher this lens becomes a fairly good performer in most materials, only the really fast f#1 and lower optics are an art to construct and are probably best made in pieces if possible. An on axis lens made in any volume material at any f# will have a dead zone in the middle where almost no light can be diffracted because the spatial frequency falls to zero. One way around this dilemma is to work with a material that forms a surface phase structure at low spatial frequencies so that the HOE transitions from a surface phase HOE in the center to a thin and then thick phase HOE as the radial distance increases. A few materials will do this to some degree. [[File:phasefig2.gif|Figure 2 Image]] '''Figure 2.''' The case of a fast off axis focusing HOE with these additional properties: # DE varies from top to bottom if ΔnT is a constant. # Bragg or fringe tilt error is typically not uniform. # Higher orders often rob power from regions of large d spacing such as near the top. # S + P (random polarization) efficiencies cannot be as high at the bottom as in the middle. Figure 3 depicts a simple slanted reflection grating, if it were unslanted we would call it a conformal mirror with about the same properties found in dielectric stack mirrors. All reflection HOEs share one advantage over all transmission HOEs, the efficiency just keeps going up with increasing modulation rather than cycling up and down. The suppression of higher orders is also better at high n but the fringe spacing is a new variable affecting color and fringe tilt and it is nearly impossible to record an off axis reflection HOE without also recording a fairly strong transmission HOE. The idea of suppressing the unwanted transmission HOE by somehow index matching it out is only wishful thinking. The plane where the fringes meet the substrate must necessarily contain the same periodic changes in index that makes the HOE efficient, so the only case where a transmission HOE is not formed is the special case of the conformal reflector. This effect is of course minimized in materials of low n that rely on significant T to get sufficient modulation. In an HUD design the surface grating produces serious flare light when flying at certain angles to the sun, for that reason alone, practically all holographic HUDs are conformal reflectors. [[File:phasefig3.gif|Figure 3 Image]] '''Figure 3.''' The simple reflection grating with the properties: # DE is proportional to ΔnT. # λ is proportional to nT + any gradient in d spacing. # Δλ is proportional to Δn + any gradient in d spacing. # Surface grating strength is always non zero except for a conformal reflector. # power lost to -1 and higher orders is usually negligible even at high Δn Figure 4 is an illustration of a fast focusing reflection HOE. In this case the surface grating changes from high to low frequency but the reflection grating is more or less constant everywhere so that the efficiency is high every where. The efficiency falls off for P polarized light when the internal angle of diffraction or reflection approaches 90 degrees so if this is important to the design a denser material would be better than a less dense material. As the average n (roughly equivalent to density) of the film falls to low values the internal diffraction angles grow larger and account for many HOE failures. One of the errors this geometry is prone to is a variable fringe spacing and tilt induced by processing. Occasionally the distortion in the fringe structure is so large that constructive wave coupling fails and the HOE loses nearly all efficiency in spite of a large modulation level. Often the color is variable across the surface indicating a non uniform internal d spacing or average n. Hoes exhibit more severe aberrations in the reflection mode compared to the transmission mode, much like conventional optics. The choice of materials and processes to control them is particularly important when designing reflection optics or reflection art work. Full color display films have to have the required sensitometric characteristics as well as true reconstruction characteristics and only a few do. There are none that do it all with high efficiency but that is not a show stopper for anything but multi-wavelength notch filters and such which can usually be made with some other material. [[File:phasefig4.gif|Figure 4 Image]] '''Figure 4.''' The very fast non conformal reflection HOE with the properties: # DE is proportional to ΔnT # λ may vary with position from process induced distortions. # Surface grating can be very intense, producing a "transflection hologram." # Higher orders are suppressed much better than in transmission equivalent with mirror backing. ===Surface phase recordings.=== Figure 5 is a representation of the surface profiles common to diffractive optics, each has been recorded in one or more phase materials and copied in many more phase materials. The single biggest advantage of surface phase structures is that they can be replicated in a dozen or more ways that do not involve the use of lasers. In fact many are made as originals without laser light or at least without interference effects. Since they can often be made optically with lasers we have to consider them and mention the common materials with their properties and uses. The three most common surface profiles are shown as sinusoidal, square and sawtooth. The sinusoidal are natural continuous phase interference patterns, the square waves could be made by interfering a lot of odd harmonics in phase but are better copied from masks generated in typeset machines or on chrome masks exposed to E-beams. The sawtooth is deeper and is sort of the equivalent to a single side band transmitter with a suppressed carrier. This shape or its interferometric equivalent which appears more rounded is the only one that puts nearly all the light into one order. An exception to this is the deep square or sinusoidal grating that is high enough in spatial frequency to have no possible higher orders and is deep enough to have some volume type wave coupled interaction that results in high efficiency. The sawtooth shape has long been machined into materials to form blazed gratings for spectroscopy and now diamond turned blazed zone plates have become common on plastic lenses where the hybrid is effectively color corrected and has reduced spherical aberration. The blazed zone plate may also be made with a single exposure through a gray scale mask in photo-resist, in some photopolymers and with lesser performance in silver grain and DCG films. It is also made in the stepped mask manner where a multilevel stair case approximation to a blaze is achieve by using from 2 to 4 masks in sequence to expose the resist. This method is limited by mask resolution and alignment and by the wavelength of light used. If the grey scale mask or its binary equivalent can be used then it is only a one step exposure limited only by the mask resolution. This general class of optics includes binary optics, embossed rainbow holograms, embossed full parallax holograms, kinoforms and all other DOEs that are not volume HOEs (VHOES). [[File:phasefig5.gif|Figure 5 Image]] '''Figure 5.''' The general surface phase structure with the properties: # Angular bandwidth (Δθ) is much larger than in volume holograms or VHOEs. # Power distribution in higher orders is a strong function of fringe shape and depth T. # T is roughly equivalent to Δn and depends on n, except for metalized reflective shapes where air is the phase shifter. # Computer generated DOEs, lithographic or machined, are now common and practical, HOEs still rule at high f₀,(pun intended). ==Matching materials== The broadest class of phase recording materials would fill a book or two so we only want to consider generic silver grain films, DCG, Polaroid photopolymers, Dupont photopolymers, PVA, PVK and Shipley photo-resist. Reference texts and papers are listed in the bibliography for recipes and other details. The new book edited by Hans Bjelkagen entitled Holographic Recording Materials is the most comprehensive single source for valuable practical material information. It is a milestone series containing 676 previously published papers covering all but PVK and PVA. Many of the papers listed separately in my bibliography are in his book. ===Silver-Halide in gelatin=== By far the most popular materials to work in are products from Agfa, Kodak and a handful of smaller producers around the world. Some are panchromatic, some have extremely fine grains, all are comparatively fast and a few have been made to work in the near IR. They are the first choice of most artists because of the sensitivity to commonly available lasers of all colors and because they may be repeatably exposed and processed to produce the widest range of visual effects. The upper range of n is on the order of .1 and the grain size varies from a low of about 10 nm to over 100 nm. Grains are a significant source of scatter and therefore produce noise in the recordings, especially at short wavelengths. This is a major consideration for most applications and for all but the smallest grain films. Just about any HOE and some DOEs may be made in silver films but they will rarely be optimized for any enough properties and if they are bleached to get the highest efficiency then other sources of noise begin contributing and grain size may grow as well. A well worked out plan for a product may utilize the speed and panchromatic properties to produce a master HOE that can then be contact copied into a material with appropriate final properties. These films can be left as clean amplitude holograms or converted to "no silver halide in gelatin" (SHG) with simple chemistry and the resultant optic will be free from scatter caused by the grains of silver. The SHG masters are especially good when copying in the blue region where the lower n works well and silver grains often produce excessive noise. A good example is the making of a HOE like figure 2 that must perform well at 680 nm. If it were made at any other wavelength than 680 it would play back with aberrations so we either have to precompensate for those aberrations or make a master at 680 nm. Both Agfa and Kodak make films that are sensitive to 680 nm and that can also readily be processed into SHG masters with a simple weak chrome bleach followed by a fix and some hot alcohol baths. Then the master can be copied at 488 into DCG or a suitable photopolymer or the much slower photo-resist. Display masters may also be made this way, taking advantage of the speed of silver (as low as 3 µj/cm²) and then creating a photo-resist submaster in a more stable set up using 442 nm light. Contact copies of even a weak hologram can be very bright when transferred to DCG provided that the ratio of reference to object light is no less than 10:1 at the bright points and the scatter from all sources is very low. We highly recommend this general procedure for any exposures that have to be made at wavelengths longer than 514 nm to about 750 nm. Diode lasers can easily be made to operate in a single mode for long enough to make a good recording and Ion lasers or cadmium lasers can do all the copying. ===DCG (dichromated gelatin)=== By far the most versatile of the phase materials, DCG in its simplest form can be used to create almost any type of HOE as long as the exposure is allowed to be done at blue green or shorter wavelengths. A few people have even made good quality HOEs with dye sensitized DCG aka DSDCG, using krypton red or big HeNe lasers. The disadvantage there is the low sensitivity of the material and low availability of strong red sources. DSDCG may require from 50 to 1000 mj/cm² @ 647 nm while DCG can be used with as little as 4 mj/cm² @ 442 nm to about 100 mj/cm² @ 514 nm. In general all the photopolymers and all the photocrosslinkers are at least 1000 times less sensitive than silver halide products. We are fortunate that low scatter can be had from both mediums or else copying from one to the other would be useless. The intrinsic noise from a highly efficient DCG HOE of moderate thickness in the 5 to 8 micron range is 1 or 2%, a very low number. The sources of noise can be controlled to that level for simple grating like structures but surface noise from dirty beams, intermodulation noise found in multi-beam or diffuse object recordings, dust on and in the film and nonlinearity noise through the bulk can all contribute to the best of the materials and not all noise sources can be eliminated. The two greatest advantages of using DCG are the intrinsic low scatter, (if hardened sufficiently), and the tolerance for many reprocessing or post processing steps to fine tune the end product. The biggest disadvantage is that you have to devote time and space to a clean coating facility and the end product is extremely sensitive to high humidity. Some products require a careful tailoring of the thickness and juggling of the sensitizer and in those cases the requirement to coat your own is a big advantage. We work with standardized mixtures and coating methods that produce 5, 8, 10 and 25 micron thick coatings that have been sufficient to make almost any HOE for the visible and near IR regions, from 450 to 1500 nm. When the material is used without much hardening it produces hazy holograms that exhibit broad spectral and angular bands but as it is hardened it also narrows and at some point it crosses into the no scatter zone quite suddenly, with no attendant change in other properties. This point is where even unexposed gelatin can no longer be dissolved out with warm water, leaving scattering centers behind. At all levels of hardness the Δn near the surface can be pushed to .25 but as in most other media that number can not be extrapolated to thicker films. Films as thick as 100 microns have been made and processed but they behave no differently than 50 micron films which in turn behave thicker than 25 micron films but have a ΔnT product that is actually lower than what is achievable at 25 microns. We think 25 to 30 microns is about the practical limit for HOEs made in DCG, which means notch filters made in DCG can trade off bandwidth for density up to that thickness but top out at a ΔnT product of about 2.5, no matter how thick or thin the film is. DMP-128 from Polaroid tops out at about 2 also, bleached silver film is about .7, PVA is about .8 after wet processing and dupont products go to at least to 1. DCG has been used successfully with all the basic configurations, including the surface relief structures. For spatial frequencies below 500 l/mm DCG and silver halide films both form efficient surface relief profiles. This works best with softer gelatin and in silver film is enhanced by repeated bleach and develop steps. In DCG the effect is enhanced by using thick film and a longer soak in a .86 SG alcohol and water mixture before final dehydration in straight alcohol. Fixing after the first processing can improve the gel hardness without destroying the relief image and then the gel can be used as an embossing master with solvent softened plastics. Hardened silver halide films work about as well. The problems related to non uniform spatial frequencies or just non uniform exposures can be fixed if they are only off by 10 or 20% by post processing DCG in baths of hot soapy water and in fixer where areas that require more modulation are dipped in hot water and areas that are too well done can be brought down with fixer. Local zones may be repeatedly painted with fixer or a 5% solution of TEA and then reprocessed in water and alcohol to balance out the plate. If an area is known to be over exposed before processing, it may be effectively unexposed with an ordinary incandescent light bulb held close to it for a few minutes. All of these manipulation methods are experimental and the rules are loose and vary greatly from thick to thin in time and intensity. Baking at about 150 C will cause the gelatin to densify and if tilted fringes are present they will appear to lay down, baking also makes the gel much more stable and a little less hygroscopic. While it is still hot a glass cap or at least an epoxy coating can be applied without trapping too much moisture in the film. Trapped moisture can become active upon heating and cause the gel to collapse here and there and everywhere. Mysterious color shifts in capped reflection holograms can be explained by the action of trapped moisture and lack of 150 bake down. The sensitivity to moisture is not the only drawback to using DCG. It will easily distort in thick films and in large area recordings in thin films it is very difficult to process uniformly. The processing leaves the fringe planes at slightly random positions and usually the film expands so that the fringes stand up while the bulk n goes down. In gratings made at near 64 degrees in and out for either reflection or transmission the diffraction efficiency for incident P polarized light is near zero, because n has dropped to about 1.3. Unless you were building a polarization separator you would not find this desirable. In fact the low n means that the difference between S and P efficiencies is always larger than in more dense media. DMP-128 also has a low average n for about the same reason, the Δn is created by producing low density voids in the film during dehydration, much like the making of aerogels. ===DMP-128 photopolymer from Polaroid=== This film has enjoyed success as a flexible film used for great looking reflection and transmission display holograms. It is also useful for making high density reflectors and because of the unique open structure it can be filled with liquid crystals to make disappearing HOEs and DFB lasers and narrowband filters. It is easier to stabilize than DCG and has about the same high modulation in films of 7 to 15 microns. All of the wet processed films seem to work best in the thickness range of from 5 to 15 microns, probably owing to limited diffusion rates in DCG and in DMP-128. This material is used mostly with red light but can be made panchromatic more easily than DCG and is much more sensitive, requiring only about 25 mj/cm² to fully expose. This material is saturable, once the polymerizeable material is used up the effects of exposure are nil. This is a great advantage in production because over exposure has almost no effect, except to maybe compress the contrast range a little. This is true of all the migratory photopolymer systems, including all of Dupont's photopolymer products. The light used to expose the hologram need not be perfectly uniform to get a uniform copy. The ratio of the reference to object wave is the primary determinant of how much modulation an area will have after an over exposure. It is a sort of self "dodging" film with a hard limit on modulation related to beam ratio. This implies that to get maximum performance a reflection or transmission master has to be as bright in its hot spots as the reference. One disadvantage of this material is that it is on a substrate that has a higher index than the unexposed film so that all recordings have a mirror in them and the film is not generally available in liquid form as of this writing. Environmental controls are important at the exposure station, because the film has to be activated by a fairly precise percentage of water or it will produce noisy holograms. The low average n may be a disadvantage for some HOES and the material tends to shrink during or after processing and needs to be babied a little to get it to reconstruct with perfect fidelity. The display holograms are the best and brightest among the mass produced products and last a very long time. Polaroid has announced the introduction of another photopolymer that also has a high n but needs no wet processing and therefore is much more suitable for precision HOE making. It will be a great boon to some of us if they market the film as Dupont does, coated and in liquid form. I don't have a clue about how it is used or how well it performs. Photopolymers, because of the dynamics of monomer migration, may make pretty poor sequential hologram recordings, each successive shot adds noise to the previous shot, and if angles are not changed sufficiently between shots in a real time material then more than one recording will be made at a time as previous recordings reconstruct and rerecord with new ones. Latent image recordings do not have this problem and some real time materials do not have migration occurring. The little things can get you. ===Dupont Photopolymers=== These are all real time recording materials with migration of monomer. They work as is or may be enhanced with post exposure baking and with the addition of a monomer to swell them to a thicker state. Swelling shifts playback color and angle in reflection holograms. The sensitivity of some films is down to a few mj/cm² but as with DMP-128 they cannot be over exposed. Some films are panchromatic and good full color holograms can be made in them. The available Δn is about .06 on a good day in the best of films so to get good brightness the films are over 8 microns thick, more typically about 20 microns. They play back with smaller bandwidths but look clear in about any light. The normal backing is mylar and is birefringent causing some problems with production and making it difficult to make HOEs with high integrity. The liquid film has been made available so that it can go on glass and then good quality HOEs are possible. A very large number of display holograms have been produced in this material, which is sold in sheets and rolls with machines to expose and process it. The limited modulation prevents this material from being used in some tasks, but it is a big plus for others. When high angular selectivity or a narrow notch filter is needed it is the material of choice, especially if you can get coatings of 50 microns or more. Optical memories have been made with it and could flourish. We made diffraction limited gratings with it. The dye never bleaches all the way out of some of their films so it is useless at short wavelengths, as is DCG and PVK. Most if not all holographic recording materials naturally absorb strongly in the UV region both long and shortwave. One of Dupont's materials forms an excellent embossed surface upon exposure and is great for copying binary or possibly shaded masks. The shading may copy with poor linearity depending on light intensities, spatial frequencies and migration rates and distances, all considerations that could spoil your day. We copied a binary mask in non embossing material and found that it was self guiding because of the real time formation of the higher index light fringes. The first light through the slits forms a guide for the rest and the usual diffractive spreading does not occur and the copied HOE is excellent except for the plastic substrate it is usually on. This is very easily used material, and stores for years in a fridge. ===PVA and PVK=== PVA (polyvinyl alcohol) has been dichromated and used as a real time material fixed with heat for many years. It is easy to get, mix, coat and use this way. It is also possible to enhance the modulation greatly by dipping it in water and alcohol, similar to DCG processes. It can also serve as a binder for a monomer and act more like other photopolymers. In its dichromated form it is a photocrosslinker like DCG and as such has no migration but the latent image in PVA is many times better than the latent image in DCG. Images and HOES are easily seen as they form in films as thin as 5 microns. The integrity of the recordings is very high with very little damage done by overwriting multiple times. As a crosslinker it is not a saturable media and can be overexposed, however it requires about a 100 mJ/cm² to form a strong recording and about 1000 more to begin to undo it. One disadvantage is that it does not adhere well to glass or plastic which makes it a perfect candidate for a transfer hologram. It is possible to form a conformal mirror in it on flat glass or plastic in a production environment and then lift it off and transfer it to a spherical surface in another off line process. It is soluble in water and unstable at high humidity but it may be possible to stabilize chemically by converting at least some of its molecules back into polyvinyl acetate or by adding crosslinking agents to a last bath. Borax is used to crosslink PVA and form "slime", baking a wet processed PVA hologram causes it to return to its original latent image state and stabilizes it somewhat against moisture. Other uses include protecting and cleaning optics and it is a common mold release agent. PVK (polyvinyl carbazole) is not soluble in water but dissolves in chloroform and in sensitized by halogens to become a photocrosslinker. It is processed in xylene and hexanes or a mono bath of miscible but differentially volatile solvents. It should only be used where maximum resistance to water is needed. It will work well in 5 micron layers, has a short shelf life and a high Δn but is hard to process uniformly. It is sensitive to blue green light and requires only a few mJ/cm². It requires the use of noxious chemicals, some of which are known carcinogens. PVK is also a commonly used photoconductor which could be used to form relief holograms in thermoplastics and for light intensifiers. If used for holography it has to be sensitized at the same time it is dissolved or it will not work, the fastest sensitizer is carbon tetra iodide and it is extremely unstable. ===Shipley Photo-resist=== Many of us use this as a standard for embossing masters. It can be obtained on plates commercially from several sources, has a long shelf life, and reasonable sensitivity to blue and UV light. We have jars of material that are 20 years old and still work about as well as they ever did. This is the most common material used to make binary optics from metal masks and it is easily metalized for production of embossing shims. We make masters from epoxy molds lifted from the resist and then mold copies in other epoxies and plastics. It is possible to make features as deep as 4 or 5 microns with little effort and resist masters may be directly converted to glass masters with reactive ion etching or with diluted HF. Some people are able to get very high aspect ratios in it and form high frequency high efficiency gratings in it. The integrity of the recording is rarely compromised in processing, but very high frequency gratings may close over at the top if the are exposed to common organic solvent fumes. Resist is user friendly and you never have to even dim the lights while working with it. All surface phase DOEs and HOEs are readily made in this material. It is often advisable to make a clean master in DCG to copy from because the exposures for reasonable sizes copies can run from several minutes to an hour, during which time a contact copy on three legs may not move but most optical setups of any size will. The required exposure is on the order of 2000 mJ/cm² @ 488 nm. Clean glass and primers and bakeouts are sometimes necessary to keep the resist on the glass and since most resists used are positive, exposure to UV after processing will break bonds and leave the material prone to falling off when you least want it to. There is a lot more to be said about designs and materials but no more room or time to say it. ==Relative material sensitivities== [[File:delta_n.gif|Average Delta n 8 microns vs. Exposure Energy in mJ/cm²]] ==References== # H. Kogelnik, "Coupled wave theory for thick hologram gratings" <em>Bell Syst Tech J. </em> <strong>48</strong>:2909-2947 (1969) # T. K. Gaylord and M. G. Moharam, "Analysis and applications of Optical Diffraction by Gratings" <em>Proc. of IEEE</em>, <strong>73,</strong> (5) (May 1985). # J.N. Cederquist and J.R. Fienup,"Analytic Design of Optimum Holographic Optical Elements" <em>J Opt Soc Am A</em><strong>4</strong>:699-705 (April 1987) # E. Hasman and A.A. Friesem, "Analytic Optimization for Holographic Optical Elements". <em>J Opt Soc Am A</em><strong>6</strong>:62-72 (Jan 1989) # F. T. S. Yu. "Effect of Emulsion Thickness Variations on Wavefront Reconstruction". <em>App Optics</em><strong>10</strong>:1324-1328 (June 1971) # R. D. Rallison "Incoherent Multifocus Hololens design and fabrication", <em>Proc. SPIE </em><strong>1183</strong>:663-668 (1989) # M. Chang and N. George, "Holographic Dielectric Grating; Theory and Practice" bibliog diags <em>Ap Optics</em><strong>9</strong>:713-719 (March 1970) # T.K. Gaylord and F. K. Tittel, "Angular Selectivity of Lithium Niobate Volume Holograms",<em> J. App Phys</em> <strong>44</strong>: 4771-4773 (Oct 1973) # J.N. Latta, "Computer-Based Analysis of Hologram Imagery and Aberrations", <em>Ap Optics</em> <strong>10</strong>:599-618 (Mar 1971) # Y. Amitai et al "Holographic Elements with High Efficiency and Low Aberrations for Helmet Displays", <em>Appl Opt </em><strong>28</strong>:3405-3416 (Aug 15 1989) # Y. Ono and N. Nishida "Holographic Zone Plates for f'0 and Collimating Lenses", <em>Appl Opt</em> <strong>25</strong>:794-797 (Mar. 1986) # J.R. Fienup "Iterative Method Applied to Image Reconstruction and to Computer-Generated Holograms", <em>Opt Eng</em> <strong>19</strong>:297-305 (May 1980) # M.R. Latta and R.V. Pole "Design Techniques for Forming 488-nm Holographic lenses with Reconstruction at 633 nm", <em>App Opt </em><strong>18</strong>:2418-2421 (July 15 1979) # E. Wihardjo, et al "Compensation of Wavelength-Shift Aberrations in an off-axis Holographic Zone Plate", <em>Opt Eng</em> <strong>25</strong>:871-874 (July 1986) # <em>Holographic Optics: Design &amp; Applications. </em>Cindrich, ed<em>. SPIE press</em> (1988). # R.C. Fairchild and J.R. Fienup, "Computer Originated Aspheric Holographic Optical Elements", <em>Opt Eng</em> <strong>21</strong>:133-140 (Jan/Feb 1982) # D. A.Winick, "Thick Phase Holograms", Environmental Research institute of Michigan, Level, (January 1981). # L. Solymar &amp; D.J. Cooke , <em>Volume Holography and Volume Gratings</em>, Academic Press, (1981). # Felix P. Shvartsman and Moshe Oren, "Photo-lithographic imaging of computer generated holographic optical elements" <em>Proc. SPIE <strong>1555</strong></em>:71-78, (1991). # A.J. Lee and D. P. Casasent,"Computer-Generated Hologram Recording Using a Laser Printer", <em>Appl Opt</em><strong>26</strong>:136-138 (Jan 1 1987) # Steven M. Arnold, "Desktop computer encoding of electron-beam written holograms" <em>Proc. SPIE </em><strong>884:</strong>23-27 1988. # R. D. Rallison , "Wavelength compensation by time reverse ray tracing", <em>Proc. SPIE </em><strong>2404</strong>: 217-225 (1995) # G. D. Mintz, D.K. Morland &amp; W.M. Boerner, "Holographic Simulation of Parabolic Mirrors", <em>Applied Optics,</em> <strong>14</strong> (3):564-570 (March 1975). # Hans Dieter Tholl "Polarization properties of volume phase gratings", Optical Engineering, <strong>34</strong>(10)2879-2885 (Oct 1995) # W. S. Colburn &amp; B. J. Chang "Holographic Combiners for Head-Up Displays", <em>Technical Report AFAL-TR-77-110</em> (Jan 1977). # Ryszard Gajewski "Holographic Technology for Solar Energy Concentration" <em>Technical Report No. 87-1479</em> (July 1984). # Jose R. Margarinos &amp;Daniel J Coleman "Holographic Mirrors" <em>Proc. SPIE </em> <strong>523</strong>:203-218 (1985). # Richard D.Rallison, "Holographic Optical Elements (HOES) in Dichromated Gelatin (DCG)", <em>Proc. SPIE</em> <strong> 523</strong>:292-295 (1985). # Jon D. Masso "Multilayer Thin Film Simulation of Volume Holograms" <em>Proc. SPIE</em> <strong>883</strong>:68-72 (1988). # H. M. Smith, <em>Holographic Recording Materials</em> Springer Verlag, 1977 # H. I. Bjelkhagen, <em>Silver-Halide Recording Materials for Holography</em>, Springer Verlag, 1995 # R. D. Rallison, "Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug.(1987) # T. A. Shankoff, "Phase holograms in dichromated gelatin" Appl. Opt. <strong>7:</strong>2101-2105 (1968) # Hans I Bjelkhagen, <em>Holographic Recording Materials</em>, SPIE publications, 1996. # R. D. Rallison "Survey of properties of volume holographic materials", <em>Proc. SPIE</em> <strong>1051</strong>:68-75 (1989) # J. L. Salter and M. F. Loeffler, "Comparison of dichromated gelatin and dupont HRF-700 photopolymer as media for holographic notch filters" <em>Proc. SPIE </em> <strong>1555</strong>:268-278 (July 1991) # R.A. Bartolini, "Characteristics of Relief Phase Holograms Recorded in Photoresists"<em>App Optics</em> <strong>13</strong>:129-139 (Jan 1974) # Tung H. Jeong, <em>Proceedings of the International Symposium on display holography,</em> Vol I (1983) # Tung H. Jeong, P<em>roceedings of the International Symposium on display holography</em> Vol II (1986) # D.J. Lanteigne and T.D. Hudson, "The DMP-128 Holographic Cookbook" Technical Report RD-RE-86-14 U.S. Army Missile Command, Nov. 1986. # J. C. Kirsch, D. J. Lanteigne and Don Gregory, "An investigation into DMP-128 Holographic Recording Material" Technical report RD-RE-87-1 U.S. Army Missile Command, Feb 1987. # D.H. Close and A. Graube, "Materials for Holographic Optical Elements", Technical Report AFML-TR-73-267, Oct. 1973. # B.J. Chang, "Post Processing of Developed Dichromated Gelatin Holograms", Opt Comm, <strong>17</strong> (3): 270-271 (June 1976). # T. Kubota, T. Ose, M. Sasake and K. Honda "Hologram Formation with Red Light in Methylene Blue Sensitized Dichromated Gelatin" <em>Applied Optics,</em> <strong>15</strong>(2):556-558 (Feb. 1976). # S.P. McGrew, "Color Control in Dichromated Gelatin Reflection Holograms", <em>Proc. SPIE </em><strong> 215</strong>:24-31 (1980). # R. T Ingwall, M Troll and W. T. Vetterling "Properties of Reflection Holograms Recorded in Polaroid's DMP-128 Plotopolymer" <em>Proc SPIE</em> <strong>747</strong>:67-73 (1987). # R. D. Rallison, "Control of DCG and non silver holographic materials" <em>Proc SPIE </em> <strong>1600</strong>: 26-37 (1991). ''Last modified on 9/16/97'' [[Category:Rallison]] ba438f0a35555c58a22d4086db3803c6f6289a78 0 477 1785 1105 2013-05-12T04:08:18Z Jsfisher 1 1 revision wikitext text/x-wiki ==Bleaching with Rehalogenating Bleach== by Jeff Blyth A successful bleach for reflection Holograms comes from using: '''60KB Rehalogenating Bleach''' *40g Ethylenediaminetetraacetic acid iron (111) sodium salt [Aldrich cat. No. 35,961-0] *60g. potassium bromide & *70 ml acetic acid Dissolved up in 1 litre water (tap water is OK here). This bleach is particularly good after a developer such as [[TJ1_Developer]] is used. ===Theory=== So what happens with in this type of bleach used WITHOUT FIXING (i.e.without removing unexposed AgBr) in thiosulfate, is that the developed up silver gets re-oxidized to AgBr. But instead of returning you to square one and leaving you with a uniform coating and distribution of AgBr again just as it was before you exposed it, it is energetically more favorable for the re-made AgBr to move over to the adjacent dark fringe made up of virgin AgBr and grow onto that dark fringe using the virgin AgBr grains as seeding centers. That actually requires the bleach solution to have some AgBr solvation ability to enable this carry-over effect to occur. This effect occurs with the help of the relatively high concentration of potassium bromide present because it does raise the solubility of AgBr in the solution through the formation of complexes. Now the great thing about this carry-over effect is that it causes almost all the original Ag in the emulsion to build up the fringes whereas if you had had to use fix you would have removed about half of your original silver content in the thiosulfate solution. A revealing experiment is to take a newly developed plate that has been in a stop bath of ~5% acetic acid, rinse it and then place it upright in a beaker so that it is half covered in a fix solution such as 20% sodium thiosulfate. After giving it gentle agitation over about 4 -5 minutes avoiding splashing the unimmersed half it is then all given a vigorous rinse under tap water. Then the whole plate is immersed in the above bleach formula and given constant agitation. The first interesting thing that will be seen is that the fixed half will take longer to bleach the dark silver than the unfixed half . This is at first counter-intuitive since one would expect that initially removing the undeveloped AgBr in the fix would later have left the bleach plenty of spare room in the gelatin to react and oxidize the silver metal without being encumbered by lots of AgBr still present. The second point that will be noticed is that when the whole plate is bleached there will be considerable scatter on the fixed half compared to the unfixed half. The increased scatter in the fixed half also testifies to the truth of that carry-over mechanism. The scatter is a consequence of the carry-over effect being unable to operate because of the missing virgin AgBr. Therefore the newly formed AgBr builds up around the dissolving silver grains in solution before reaching a level where it becomes energetically favorable to precipitate out. The precipitate will be in larger grains and to some extent will occur in the dark fringe areas where the gelatin is supposed to be free of AgBr in order to give good fringe contrast with the new AgBr in the light fringes. The finished hologram if it had been recorded in red will now be shifted to the green, scattery, and less bright than the unfixed half. ===Bleaching Transmission Holograms=== The formulation above has been found to work pretty well also with transmission Holograms (Hs). The not-so-good thing about it though is that the original sensitizing dyes become chemically locked into AgBr grains making the emulsion very vulnerable to print out, i.e. darkening slowly in ambient lighting, particularly sunshine. The dyes can be chemically inactivated with a 2% potassium or ammonium dichromate bath-- it takes about a minute after you have used the Ferric EDTA bleach. ===A Good Bleach for Transmission Holograms, (can also be used to make reflection ones with a shorter replay wavelength)=== A better bleach for transmission holograms is to dissolve up 0.5 to1 gram of iodine crystals in about 200 ml alcohol (methanol or ethanol) and then about 200ml of water is added. However before putting the plate in, it is essential this time to use fix. This is because the bleach has no carry-over power. The fix bath can be 20% sodium thiosulfate and the plate given about 4 minutes in it with mild agitation. It is then given a thorough rinse under tap water to remove all traces of fix. After the bleach step the iodine stain can be removed in a 70% alcohol bath. A very good point about this bleach is that the dyes are released by the fix and easily removed in the alcoholic iodine solution. A comparison was made by cutting a developed and stopped (5% acetic acid) transmission H in half and then bleaching one half in the ferric-EDTA bleach and the other half after fixing was put in the iodine bleach. The iodine bleached half finished up producing a slightly higher diffraction efficiency. (This could be due to the carry-over effect being less efficient in the larger fringe spacing of transmission Hs compared to reflection Hs.) If you choose to use this bleach on say a '''reflection hologram''' made with a red laser then you can get a quite nice final yellow-green replay color because contraction occurs due to loss of the original virgin AgBr in the fix solution. (You also get a little bit of expansion due to AgI replacing AgBr.) It may then look brighter than a red one would have looked because of the eye's extra sensitivity to light-green even though some valuable AgBr diffracting material has been lost ===References=== P. Hariharan, C.M. Chidley; Rehalogenating Bleaches for photographic phase holograms 2: spatial frequency effects. Appl. Optics. 27 No.18, 3852 (1988) ) 5e0c98d115c38a2527d85fc56af04c73e5eca7d5 0 847 1787 1786 2013-05-12T04:08:19Z Jsfisher 1 1 revision wikitext text/x-wiki <center><strong> Bio for Richard D. Rallison<br> Box 142, Paradise, Ut 84328<br> (435) 245-4623&nbsp; E-mail rdr@ralcon.com </strong></center> <p> <strong>Education:</strong> </p> <ul> <li>Engineering Studies, Utah State University, 1964-1968 </li> <li>B.S.E.E., University of Utah, 1969-1973 <strong>(Cum Laude).</strong> </li> <li>M.S.E.E. Laser Systems, U.S.C. 1974-75 (not completed) </li> <li><strong>Ph.D. Electro Optical Engineering, Honorary, USU 1995</strong> </li> </ul> <p> <strong>Experience and prior work</strong> </p> <blockquote>Approximately 35 years of professional or technical grade experience. Has been engaged in development work of CO2 Waveguide, Co-Axial Cadmium, Doubled "blue" Yag and Dye lasers at Hughes Aircraft for space communications, countermeasures and underwater communications. Performed ION laser design upgrades at American Laser Corp. and fabricated a novel multiple pass Ruby laser system for Dikrotek. Experienced with diode lasers including fabrication of a small bar code scanner for that coupled a diode laser, grin rod and focusing holographic scanner together. Another device developed and co patented with IBM splits diode laser light into polarized components and replaces a Wollaston prism. </blockquote> <blockquote> An early commercial success for IBM was the development of holographic scanner fabrication methods in 1979, followed by many years of development in Holographic elements, devices and systems and sales of Holographic Optical Element (HOE) fabrication technology to IBM, Pilkington(UK), Holosonics, Seimens, Raven Holographics in England, Portson Inc of Kansas., APA Optics of MN, Northrop corp of CA., Metrologic Instruments of NJ, Process Instruments of SLC, Bell Resources in Australia and Terabeam of Seattle. </blockquote> <blockquote> Work for NASA beginning in 1990 to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have begun. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s. Many spectrographic optical designs, head mounted display designs and some holographic memory designs have been made and brass-boarded. Some have become commercial products. </blockquote> <blockquote> Mr. Rallison has served as a consultant in Diffractive Optics for dozens of companies and has given numerous lectures on holography at the University of Utah, USU and Lake forest College as well as occasional invitations to give paid tutorials in industry. </blockquote> <blockquote>Other work includes the design and fabrication of novel HUD optics for the Air Force on an SBIR<br> grant and an investigation of new holographic recording polymers for the Army NVL on an SBIR contracts. Contracts have been successfully completed for the army at Aberdeen where 5 HMDs were designed fabricated and delivered. Work for VIO in Seattle involved design and fabrication of Stereo Color HMDs or their components. 10 years of work on NASA contracts to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have been attempted. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s such as telecom receivers for free space interconnects developed for another Seattle company named Terabeam, co-founded by RD Rallison.<br> <br> He has fabricated multi lens arrays, gratings, HUDs, notch filters, Fourier filters, scanners, co-phasal multiplexed gratings, spectrophotometer gratings and filters, reflectors, diffusers, depixelators and assorted other HOEs. He owned and operated a company that produced millions of high quality display holograms for commercial use over a 10-year period. He worked as a Video Engineer and Cameraman for a CBS affiliate and prior to that performed work related to weather modification at the Utah Water Research Lab while also producing commercial light shows and devices for entertainment type productions. </blockquote> <p> <strong>Current Organization:</strong> </p> <blockquote>Ralcon Corp. is a vehicle for Mr. Rallison to consult in Optics and develop products. He owns an 8000 square foot facility in Paradise, Utah where laser and Holographic Optics development work has been going on since 1985.The facility is equipped with Argon, Yag, Dye, Nitrogen, HeNe, Ruby and various Diode lasers. Four floating stable tables of various sizes in well insulated rooms provide the basic optical beds and each has its own Argon, HeNe and YAG laser. A machine shop with a variety of glass shaping and polishing machinery compliment the holographic optical fabrication facility. Ralcon Development Lab (RDL) ceased commercial business in June of 2004 at the request the Cache County planning and zoning commission. Commercial customers of RDL have been referred to Wasatch Photonics in Logan UT, which was created in part to continue the work of RDL. Work at RDL is limited to research for NASA GSFC and other government labs.&nbsp;&nbsp; <br> </blockquote> <p> <strong>Professional Affiliations:</strong> </p> <ul> <li>Institute of Electrical and Electronic Engineers </li> <li>Sigma Tau (Honorary Society) </li> <li>Society of Photo Optical and Instrumentation Engineers(SPIE) </li> <li>Optical Society of America (OSA) </li> <li>Aircraft Owners and Pilots association (AOPA) </li> </ul> <p> <strong>Licenses:</strong> </p> <ul> <li>First Class Radio Telephone </li> <li>Private Pilot, SEL, RH, Glider, Hang Glider<br> </li> <li>CDL -class A-air-trailer<br> </li> </ul> <p> <strong>Patents:</strong> </p> <ul> <li>#4,913,990 "method of tuning a volume phase hologram" </li> <li>#5,303,085 and #5,619,377 "Optically corrected helmet mounted display" </li> <li>#4,950,067 "optical system that helps reduce eye strain" </li> <li>#5,291,316 "Information display system having Transparent Holographic Optical Element" </li> <li>#5,602,657 "Hologram system having hologram layers with rotationally offset Bragg planes" </li> <li>#5,519,517 "Method and apparatus for holographically record and reproduce images in a sequential manner" </li> <li>#6,097,543 "Personal Visual Display" </li> <li>#5,991,087 "Non-orthogonal plate in a virtual reality or heads up display" </li> <li>#5,991,085 "Head mounted personal visual display apparatus with image generator and holder" </li> <li>#5,949,583 "Head mounted display with image generator, fold mirror and mirror for transmission to the eye position of the user" </li> <li>#5,945,967 "speckle depixelator" </li> <li>#5,903,396 "Intensified visual display" </li> <li>#5,903,395 "Personal visual display system" </li> <li>#5,864,326 "Depixelated visual display" </li> <li>#5,751,425 "Raman spectroscopy apparatus and a method for continuous chemical analysis of fluid streams" </li> <li>#6,100,975 "Raman spectroscopy apparatus and method using external cavity laser for continuous chemical analysis of sample streams" </li> <li>#5,673,151 "Image correction in virtual reality and heads up displays" </li> <li>#5,642,227 " Optical correction for virtual reality and heads up displays"</li> <li>#6,678,079 “Transceiver for a wireless optical telecommunication system “</li> <li>#6,608,708"System and method for using a holographic optical element in a wireless telecommunication system receiver”<br> </li> <li>#6,369,952 “Head-mounted personal visual display apparatus with image generator and holder”<br> </li> <li>#6,160,666 "Personal visual display system”<br> <br> </li> </ul> <p> <strong>Awards:</strong> </p> <ul> <li>Dept of Defense SBIR Quality Award </li> </ul> <p> <strong>Publications:</strong> Follow [[Publications|this]] link to see our publications list, including links to online versions when available. <br clear="all"> </p> <p></p> <hr> <hr> <h4><em>Last modified on 9/13/2000 [[Category:Rallison]] 980c644ecde2c5a43ad3db53da1fabcfc5bdb08b 0 478 1789 1107 2013-05-12T04:08:19Z Jsfisher 1 1 revision wikitext text/x-wiki ==The Reversal Bleach system== by Jeff Blyth The most popular form of this type originally used dichromate salt and sulfuric acid. It has been of particular value for use on the AGFA 8E75 HD plates and film because when used correctly it can produce the lowest levels of light scatter. Its popularity for Denisyuk reflection holograms made with 633nm from HeNe lasers also comes from the inclination to hit the fairly elusive yellow replay coloration due to the right amount of emulsion shrinkage. I consider that its chief asset today with finer grain materials available is as a bleach for transmission holograms. It has good printout resistance (i.e. low tendency to darken in ambient lighting over time) and can produce high diffraction efficiency. However for Denisyuk reflection holograms it does not achieve as much diffraction efficiency as can be obtained from a good rehalogenating bleach. People using it have however failed to appreciate that the developer used beforehand should not contain silver halide solvents such as sodium sulfite and urea, and the need for the rigorous exclusion of halide contaminants as discussed in the Theory section. A suitable developer for use in conjunction with this bleach is [[TJ1 Developer]]. The proportions used in the formulation is hugely tolerant of variation. I have chosen to use a lower concentration of dichromate compared to previous publications because it leaves the bleached hologram with less yellow coloration from the dichromate salt and this means less rinsing is required to remove it. Increasing the dichromate proportion will reduce the time taken to bleach the dark silver. I have substituted sulfuric acid with the more manageable solid salt sodium hydrogen sulfate. (This is in fact a semi-neutralized form of sulfuric acid). The basic formula is: *1 g. potassium dichromate (or ammonium dichromate) *10g sodium hydrogen sulfate. *made up to 1 litre in distilled or de-ionized water. The set up should include 2 baths of de-ionized water (DI) as follows: '''Bath 1''' *DI with *4% acetic acid (Acts as a “Stop” to stop developer action) '''Bath 2''' *DI '''Bath 3''' *Reversal Bleach ==Procedure== #After development, a brief 10 second rinse under running tap water then a good rinse in Bath 1. for ~1 minute . #A good rinse in Bath 2. ~1 minute #Immerse in Reversal bleach (Bath 3) and gently agitate until no dark silver remains #Important- after the bleach bath the hologram should be put first back in DI (Bath 2) for ~ 20 sec. before being rinsed under tap. ==Theory== The idea might seem simple enough, after development the developed up silver is dissolved up into the solution and removed from the gelatin film so that then leaves the undeveloped virgin AgBr in the dark fringes to make the hologram. So in effect it both “fixes” and bleaches. The good point about it is that it has a high resistance to printout or darkening in ambient light and can have low scatter levels with holographic plates that do not have the smallest AgBr grains such as the old Agfa material, the lowest scatter comes about provided you understand what you must do to stop any soluble halide ions getting into your hologram before you have finished processing. ==Developer considerations== Because of the way this bleach operates, particular consideration has also got to be given the developer system used first. It is not satisfactory to have any “physical development “ which encourages silver bromide to be dissolved in the developer. We need to have as much virgin AgBr as possible to create our final diffraction and it makes no sense to load up the developer with sulfite ion­ a weak silver halide solvent and similar remarks apply to urea as in the CW developer. The amount of development is also more important than in the case of the rehalogenating bleach system. Since all the developed silver is going to be washed away, if you develop too much for too long then you start to eat into your virgin AgBr in the dark fringes because even unexposed AgBr is developable given enough time. The consequence is that reflection holograms made with red lasers may look a dull green instead bright yellow/green due to increased contraction . This effect has also been shown to cause a peak in the graph of diffraction efficiency vs. developer/exposure level and after the peak the efficiency drops away. Whereas when a rehalogenating bleach is used after the same developer conditions, the diffraction efficiency flattens off. [Joly] ==Importance of De-ionized rinsing water.== After the developer the hologram needs a good rinse under tap water to remove the developer and soluble bromide and iodide ions in it . Even if the developer had no halide ions initially, the development process means that the AgBr and AgI in the emulsion had to be broken up and turned into dark silver and soluble Br- and I-. The tap water rinse then leaves the emulsion with just chloride ions from tap water which are less of a problem to deal with later than soluble bromide or iodide ions. Before the dichromate bath is used you have to have two pre-baths of de-ionized water (DI) to remove all traces of dissolved halide ions. If you don’t do this then some of the developed up silver fails to be removed from the light-struck fringes and deposits itself back in the fringe as silver halide. This causes scatter in the finished hologram and reduces diffraction efficiency because the light struck fringes have failed to be properly cleared of AgBr . Where even experienced holographers commonly go wrong is that after removing the bleached hologram from this reversal bleach bath, they rinse it under the tap instead of first putting the hologram back in de-ionized water for a second time . This is because after leaving the bleach bath the hologram is full of silver ions in solution which can instantly form silver chloride particles with the chloride ions in tap water. So this causes scattering from inside the emulsion which cannot be wiped away even if surface silver chloride can be. After using the bleach bath you may notice a red-brown precipitate or scum in the bath. This is normal and it is actually good to have it in there. It is made up of silver chromate or dichromate which is not very soluble but is far more soluble than are the silver halides. So what this red sludge means is that your bleach bath is saturated with silver chromate in solution and any stray halide ions in solution are effectively precipitated out before they can get inside your emulsion. Even though some precipitated silver chromate may form in your gelatin layer it comes out easily in the DI bath. After this final DI bath you can then rinse the hologram in tap water to eliminate any dichromate ions if you wish, because there will be no soluble silver ions to cause trouble in a final tap water rinse. (Personally I like having a trace of dichromate in the hologram not washed out because it helps to prevent future printout. However dichromate is quite poisonous and who knows what future use your hologram may be put to particularly with young children around). ==Tap water rinsing== Prolonged tap water rinsing can remove some of your AgBr with significant differences depending on time of year and the temperature of your cold water supply. Any AgBr loss causes a shift to a shorter wavelength replay in the case of reflection holograms and of course some loss in diffraction efficiency but sometimes people prefer to simply shift the color from orange-yellow to yellow-green using a hot water rinse. The result can look brighter, also any scatter from AgCl contamination can be removed because AgCl is about ten times more soluble than AgBr. Some idea of the temperature effect can be seen from this graph: [[Image:SilverSolubility.gif]] ==References== [Joly L., Jacobs P. Spectral Response of reflection gratings on Holotest 8E75 HD Proc. Int’l Symp. on Display Holography, ed. Jeong, T.J. Lake Forest College IL. Vol III p115-126 (1989).] [Owen, B.B. and Brinkley, S.R. J.A.C.S. 60, 2237 (1938).] e75fa688214d0f9739dcc8f1b19b689401b54caa 0 481 1791 1113 2013-05-12T04:08:19Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:RLakes.jpg]] [[http://silver.neep.wisc.edu/~lakes/ Rod's Website]] *Columbia University, Mathematics, 1964, 1965 *Rensselaer Polytechnic Institute, B.S., 1969; Ph.D., 1975 *Yale University, Research Associate, 1975 -1977 Applications of holography: experimental mechanics Lakes, R. S., Gorman, D., and Bonfield, W., "Holographic screening method for microelastic solids", J. Materials Science, 20 2882-2888 (1985). Classical elastic and Cosserat elastic materials may be quickly distinguished via holographic study of displacement of a notch at the corner of a square section bar in torsion. Chen, C. P. and Lakes, R. S., "Holographic study of conventional and negative Poisson's ratio metallic foams: elasticity, yield, and micro-deformation", J. Materials Science, 26, 5397-5402 (1991). This article presents an experimental study by holographic interferometry of the following material properties of conventional and negative Poisson's ratio copper foams: Young's moduli, Poisson's ratios, yield strengths, and characteristic lengths associated with inhomogeneous deformation. The Young's modulus and yield strength of the conventional copper foam were comparable to those predicted by microstructural modelling on the basis of cellular rib bending. The re-entrant copper foam exhibited a negative Poisson's ratio as indicated by the elliptic contour fringes on the specimen surface in the bending tests. Inhomogeneous, non-affine deformation was observed holographically in both foam materials. Download pdf Lakes, R. S. and Elms, K., "Indentability of conventional and negative Poisson's ratio foams", J. Composite Materials, 27,1193-1202, (1993). The indentation resistance of foams, both of conventional structure and of a novel re-entrant structure giving rise to negative Poisson's ratio, was studied using holographic interferometry. In holographic indentation tests, re-entrant foams had higher yield strengths sigma y and lower stiffness E than conventional foams of the same original relative density. Damage in both kinds of foam occurred primarily directly under the indenter. Calculated energy absorption for dynamic impact is considerably higher for re-entrant foam than conventional foam. Chen, C. P. and Lakes, R. S., "Holographic study of non-affine deformation in copper foam with a negative Poisson's ratio -0.8", Scripta Metall et Mater., 29, 395-399, (1993). Negative Poisson's ratio copper foam (Poisson's ratio -0.8) with a permanent volumetric compression ratio of 2.2 exhibits a greater non-affine (inhomogeneous) deformation than either conventional foam or negative Poisson's ratio foam (Poisson's ratio = -0.1) with a volumetric compression ratio of 3. Anderson, W. B., Lakes, R. S., and Smith, M. C., "Holographic evaluation of warp in the torsion of a bar of cellular solid", Cellular Polymers, 14, 1-13, (1995). Holographic methods are utilized to examine deviations from classical elasticity in a cellular solid, polymethacrylamide closed cell foam. A square cross section bar is subjected to static torsional deformation. The warp deformation is observed to be less in a foam bar than in a homogeneous polymeric bar used as a control. The homogeneous bar obeys the predictions of classical elasticity. Behavior of the foam bar is consistent with Cosserat elasticity. In a Cosserat solid, points in the continuum to rotate as well as translate, and the material supports couple per unit area as well as force per unit area. Cosserat effects can lead to enhanced toughness. This image shows holographic fringes associated with warp. Development of holographic methods Lakes, R. S., "Multi wavelength techniques in holographic interferometry", Journal of Modern Optics, 35(9), 1459-1465 (1988). Techniques are presented which take advantage of the wavelength dependence of various phenomena in holographic interferometry. Image-plane interferograms illuminated with light containing multiple wavelengths exhibit color dispersion of the fringes. We extract from this dispersion, full- field information concerning displacement components which are not disclosed by monochromatic illumination. Cohen, B. and Lakes, R. S., "Aberration reduction in one step lens image plane holography", Applied Optics, 27, 3322-3323 (1988). A simple correction scheme is presented, which permits the use of large aperture lens systems of modest quality, even single element lenses, to produce image plane holograms viewable in white light. The present method allows white light reconstruction and corrects field curvature, which is the most objectionable aberration in display holograms. The field curvature was corrected by making the hologram with diverging light and illuminating the hologram with collimated light to introduce a compensating negative curvature of field. Wuest, D. and Lakes, R. S., "Color control in reflection holograms by humidity", Applied Optics, 30, 2363-2367 (1991). A method is presented which permits control of the reconstruction wavelength of reflection holograms and holographic optical elements [HOE's]. This approach makes use of developer and bleach which minimize emulsion shrinkage combined with control of ambient humidity to control the emulsion shrinkage during formation and reconstruction. A simple index matching approach to the elimination of the wood grain effect in reflection holograms is also presented. Applications: Holographic Optical Elements Wadle, S. and Lakes, R. S., "Holographic diffusers: polarization effects", Optical Engineering, 33, 1084-1088, (1994). In some applications of diffusers, it is desirable to minimize the diffuse back reflection of light. Use of polarized light is one way to reduce this back reflection. To that end, the effect of diffusers upon polarized light is studied experimentally. Diffusers based on ground glass, white plastic containing scatterers, and holographic optical elements are considered. The ground glass and HOE diffusers preserve polarization in the diffusion process, but the white plastic does not. Diffuse back reflection from ground glass or holographic diffusers can be significantly reduced by the use of an isolator based on a quarter wave plate. Wadle, S., Wuest, D., Cantalupo, J., and Lakes, R. S., "Holographic diffusers", Optical Engineering, 33, 213-218, (1994). Holographic diffusers were prepared using silver halide (Agfa 8E75 and Kodak 649F) and photopolymer (Polaroid DMP128 and DuPont 600, 705, and 150 series) media. It was possible to control the diffusion angle in three ways: by selection of the properties of the source diffuser, by control of its subtended angle, and by selection of the holographic medium. Several conventional diffusers based on refraction or scattering of light were examined for comparison. Wuest, D. and Lakes, R. S., "Holographic optical element for projection of stereo images", Applied Optics, 31, 1008-1009 (1992). We present a holographic element capable of projecting dynamic stereo images, and allowing the observer to see through the device, for possible use as a head up display in aircraft. The device is based on a volume reflection holographic optical element which contains two sets of Bragg planes. Each set of Bragg planes diffracts light from a two-dimensional source to the appropriate eye to achieve a stereo effect. Lakes, R. S. and Vick, G., "Partial collimation of light from a diffusely reflective source", J. Modern Optics, 39, 2113- 2119, (1992). A general purpose collimator capable of collimation of radiation from an arbitrary thermal source of diffuse light is incompatible with the second law of thermodynamics. However there are 'special purpose' collimators which would not be generally applicable. A new collimator which is effective when placed close to a white (diffusely reflective) source is presented. Wadle, S. and Lakes, R. S., "Holographic diffusers with low back-scatter", J. Modern Optics, 42, 1387-1396, (1995). Holographic diffusers have been produced with very low back diffusion in comparison with diffusion in the forward direction. Reduced back diffusion was achieved by lamination and index matching procedures which minimized the formation of Bragg planes parallel to the film surface. Photopolymer media were used as phase media. Diffusers with the lowest values of back diffusion were prepared by moderately restricting the field angle of incident light during formation. 9a8ab2dc30f42f98e478de8102593954aa0be29d 0 482 1793 1115 2013-05-12T04:08:19Z Jsfisher 1 1 revision wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 485 1797 1121 2013-05-12T04:08:20Z Jsfisher 1 1 revision wikitext text/x-wiki [http://rudieberkhout.home.mindspring.com/home.htm Rudie Berkhout] Rudie Berkhout was a Artist/Holographer from Leeds NY. He had an extensive list of publications about holography and regularly exhibited his work. Born in Amsterdam, Berkhout came to the United States in 1974 with a background in engineering and lighting to study at the New York School of Holography. He later researched white light holographic techniques and pulsed holography at the New York Art Alliance laboratories. He created the first flat display system for holographic movies (Integral holography or holographic stereograms first developed by Lloyd Cross) while at the Holographic Film Company in New York (founded by cinematographer Hart Perry). Until this time, holographic stereograms had been viewed only in the round. Berkhout also designed and built a time-lapse recording system to enable artists to capture as much as four hours of movement in a single hologram. A major contribution to the medium was his work in color control and image multiplication which resulted in his breathtaking "Twelve Milliwatt Boogie" first exhibited in 1979 at the Museum of Holography, New York. This stunning piece set a standard in white-light transmission holography with its boldly-colored geometric figures floating in three-dimensional space. Rudie Berkhout passed away from a heart attack on Tuesday 16 September, 2008. 12495e5074373e7c65f22444dd5c9c44ed7bd6e4 0 491 1799 1133 2013-05-12T04:08:20Z Jsfisher 1 1 revision wikitext text/x-wiki DCG holograms are very sensitive to re-adsorbing moisture. If a hologram disappears after bieng in humidity you can usually get the image back by reprossing the hologram in alcohol drying baths. If you want to make sure the hologram is permanent you will need to seal the back side. The two most common methods are to seal the back with a glass plate or to coat the back with a cyanoacrilate adhesive. Most art holographers use the glass plate method. == Glass Plate Method 1 - Full Coverage (UV Epoxy) == When sealing a hologram with the glass plate method it is important to scrape at least 3mm of gelatine off the edge all the way around the hologram. This insures that the edge of the gelatin is sealed. Once this is done the epoxy is spread evenly over the entire emulsion and a glass plate is place over the sealant. The entire sandwich is place over or under a UV light (black light) to cure. This sealant is bought to have the same index of refraction of glass and should dry clear. This sealant can be expensive. If you wish to make your own UV sealant see Jeff Blyths "Do It Yourself" UV sealant below. == Glass Plate Method 2 - O-Ring (Standard Epoxy) == An ecconomical approach that works very well is to use 5 minute two part epoxy (at any hardware store). Scrape 3mm of gelatin off the edge all the way around as indicated above as best as you can. Clean the glass cover plate. Mix the two parts of the two part epoxy as directed on the epoxy label. I use a q-tip cut in half and a piece of scrap glass. Once the epoxy is mixed use a tool, like the q-tip rod to evenly spread a bead of epoxy around the scraped 3mm area on the hologram. Place the cover plate on and insure there are no place missing any epoxy by visually inspecting it. Place on level surface and let dry. '''Here is a post from Jeff Blythe on making UV cure epoxy at home:''' ===A DIY UV sealant=== In keeping with the grand DIY philosophy of the Forum I thought I would put down some basic ingredients for making your own out of materials which are fundamentally cheap because of their big industrial use. However before that a hypothesis that fits observations I have made. I believe that the reason DCG has been so notoriously difficult to seal up and prevent moisture getting in is not necessarily due to any fault of hydrophobic glues being somehow rather more moisture pervious than expected. I believe the real trouble has been that sandwiched between 2 glass sheets the gelatin layer contracts with age and builds up a significant vacuum. This results eventually in outside air getting through microcracks inspite of diligently thick glue having been applied around the edges of the sandwich.. This contraction effect might be just to do with the basic properties of the gelatin under prolonged lighting but it could well be more to do with the final stubborn traces of water /alcohol still hanging about and alcohol vapour can very gradually (we can be talking “years” here) make its way through the edge sealant increasing the vacuum effect. Anyway whatever the cause an obvious way to minimise it is to put the newly processed DCG in a really dry warmer I am not sure what temperature is best but 60-70C for as long 24 hours seems to work or alternatively I have left them in a really effective desiccator for a week. Then without giving the ultra dry DCG a chance to re-absorb ambient humidity a dry glass cover plate with dry sealant can be put on. This topic has been discussed on the forum before and some of you guys have had vastly more experience than me at sealing. To make a UV curable sealant,you need a monomer, crosslinker, and free radical generator for UV. Monomer : Methyl methacrylate or better (more hydrophobic) is butyl methacrylate (NB. Not tert-butyl methacrylate) Crosslinker: Ethylene dimethacrylate (alternative silly name by Sigma Aldrich is ethylene glycol dimethacrylate). UV sensitizer (free radical generator in UV.): DMPA or dimethoxyphenyl acetophenone. One can use about 1 part DMPA to 100 parts monomer to 5-10 parts crosslinker. It gets harder the more crosslinker you add of course. (~80-100% crosslinker just cracks up). But the mix has initially a rather low viscosity , lower than the commercial stuff. It is a good idea to store mixture over silica gel in a fridge in the dark. Jeff 04551d1a55302ad8c0ac37991d9f6fb8e031cd24 0 493 1801 1137 2013-05-12T04:08:20Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:SVorobyov.jpg]] A physicist, expert in holography, Ph. D. of technical sciences. Sergey Vorobyov has been studying holography since second year of the university. During 30 years of his work, he took part in the development of the main directions of applied holography - hologram manufacturing on silver-halide photomaterials, hologram production on dichromate gelatin, manufacturing of holograms for information systems, embossed and color holography and etc. Sergey Vorobyov was a member of the commission on industrial application of photoplates for holography: PFG-01, PFG-02, PFG-03, PFG-04 at the Slavich company. He took part in testing those plates and optimization of the manufacturing process. Sergey Vorobyov is director of holographic studio at the All-Russian Exhibition Center (Moscow). He developed unique technology of recording and copying of pulse holograms. Commercial manufacturing of display holograms has been organized with his help. Sergey constantly improves technology of manufacturing of transmission and reflection holograms. As a holography popularizer he wrote the course "25 holography lessons". It has been published in Russian and English on [http://www.holography.ru www.holography.ru] web site. Sergey Vorobyov also developed the compact kit for amateur holography. f198df26477f86b0c9892de50a49c1b2ea8cecbb 0 494 1803 1139 2013-05-12T04:08:21Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:SZharkiy.jpg]] Sergey Zharkiy graduated from the Moscow State University, Faculty of Physics with a MS (Master of Science) in Physics in 1999. He studied lasers and holography at the International Laser Center of Moscow State University. He took part in scientific conferences with his articles on holography and laser applications. Sergey Zharkiy is an author and developer of [http://www.holography.ru Holography.Ru] web site. He wrote and translated many articles for this web site. Sergey also designed and made several art holograms for gallery of Russian Holographic Studios. Sergey Zharkiy took part in development of compact holographic kit for amateur holographers. He is also author and director of educational film (DVD) on holography. 38787c57278d1cf03021f1544097ac7ecf9e658e 0 496 1805 1143 2013-05-12T04:08:21Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.mccormackholography.com/ Sharon's Website] Sharon McCormack was born in New York City and now lives and works in the Columbia River Gorge National Scenic Area, White Salmon, Washington. Since 1975, Sharon's professional activities have included Owner/ Director, School of Holography, San Francisco, CA to holographic lens system construction for X-ray applications to lecturing, consulting, and commissioned work in the field of holography. Over that period, Sharon has created numerous world-wide group & solo exhibitions, has won many prestigious awards & grants, and has been featured in a broad range of publications from technical journals to sport magazines. 40b8e36f158ef1844bb85c80f16a54396ebc55ec 0 500 1807 1151 2013-05-12T04:08:21Z Jsfisher 1 1 revision wikitext text/x-wiki {| align=center border=1 | Material | Thickness (um) | Sensitivity uj/cm2) Sectral Sensitivity (nm) | 442nm | 514nm | 633nm | 694nm | Resolving Power lp(mm)-1 |Grain Size (nm) |- | '''Slavich''' |- | PFG-01 | 7 | <700 | | | 80 | | >3000 | 35-40 |- | PFG-03M | 7 | <700 | | | 1500 | | >5000 | 10-20 |- | VRP-M | 7 | <550 | | 80 | | | >3000 | 35-40 |- | PFG-03C | 9 | 400-700 | 1000 | 2000 | 1000 | | >5000 | 10-20 |- | '''Colourholographic''' |- | BB-700 | 7 | <700 | | | 50 | 150 | >2500 | 50-60 |- | BB-640 | 7 | <650 | | | 150 | | >4000 | 20-25 |- | BB-520 | 7 | <540 | 150 | 150 | | | >4000 | 20-25 |- | BB-450 | 7 | <470 | 150 | | | | >4000 | 20-25 |- | '''Kodak''' |- | 131PX | 9 | <650 | 2 | | .5 | | >1250 | 70 |- | 131CX | 9 | <650 | 2 | | .5 | | >1250 | 70 |- | 120PX | 6 | <750 | 60 | | 40 | 40 | >1250 | 70 |- | 120CX | 6 | <750 | 60 | | 40 | 40 | >1250 | 70 |- | '''FilmoTec-ORWO''' |- |GF40 (gelantin film) |6 | UV to blue-green after sensitisation | | | | |not relevant | |- | HF53 | 6 | <550 | |1000 at 535nm | | | >5000 | |- | HF55 | 6 | <550 | |250 at 535nm | | | >3000 | |- |HF65 |6 |580 to 660 | | |<100 | |>3000 | |- | '''Ultimate''' |- | Ultimate 15 | 7 | <700 | | 150 | 150 | 150 | >5000 | 15 |- | Ultimate 08 | 7 | <650 | 120 | 200 | 200 | | >7000 | 8 |- | '''Fuji''' |- | HL-30 | | 100-200 | | | | |3000 |30-40 |- |} b455b4b9391b1cd1d893ba01c227d577056983f4 0 501 1809 1153 2013-05-12T04:08:21Z Jsfisher 1 1 revision wikitext text/x-wiki Silver Halide is one of the most popular recording materials. The historical and available commercially available films properties are listed here: *[[Silver Halide Film]] *[[DIY Silver Halide Film]] *[[Silver Halide Processing Chemistry]] *[[Silver Halide Film vs Chemistry vs Hologram Type]] *[[Silver Halide Sensitized Gelatin]] SHSG *[[Index Matching]] *[[Pre-Swelling]] *[[Post-Swelling]] *[[Squeegee Technique]] *[[Fringe Photos]] *[[Painting Holograms]] *[[Exposure Tests]] *[[Hardening Holograms to Fix the Color]] *[[Psuedocolor Processing]] *[[Laminating Film to Glass]] 3454f949841c27174a442f2f07ec80d99d76760f 0 503 1811 1157 2013-05-12T04:08:21Z Jsfisher 1 1 revision wikitext text/x-wiki Described here are sucessful chemistries to use for each qualifying film for a particular type of hologram. For specific formulations look at [[Silver Processing Formulas]]. ===Single Beam Transmission - Film vs Chem=== ====PFG-01==== For low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up. (Ed Wesly) ===Single Beam Reflection - Film vs Chem=== ====PFG-01==== (Ed Wesly)- Replay in the same wavelength use CWC2 developer with PBQ rehalogenating bleach (Ed Wesly)- Replay is color shifted use Pyro or CWC2 developer with Dichromate reversal bleach Replay in same color use JD3 - Integraf Replay shorter use JD2 - Integraf ====PFG-03==== (Ed Wesly)- Replay is same wavelength use Slavich Hardener with G2 Developer and Slavich Fixer ====BB640==== (Ed Wesly)- Replay in the same wavelength use Pyrogallol based developer with Rehalogenating bleach ===H1 Transmission - Film vs Chem=== ====PFG-01==== (Ed Wesly) - Replay in the same wavelength use CWC2 developer PBQ rehalogenating bleach Another case is for low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up (Ed Wesly). ===H2 Transmission - Film vs Chem=== ====PFG-01==== Another case is for low frequency gratings, use develop reversal bleach or develop fix rehalogenate, for if the fringes are too far apart the "swim" of the materials from one fringe to the other is too far and not much modulation occurs. I discovered this when I made a low spatial frequency grating (the fringes were about 30 line pairs per mm, as you could see them with a strong magnifying glass) and the transmission grating was weak, but the single beam reflection holo of the back side of the glass (the dreaded woodgrain) was decently bright! I switched to develop/reversal bleach and painted the back of the plate back to fix things up (Ed Wesly). ===H2 Reflection - Film vs Chem=== ====PFG-01==== (Ed Wesly) - Replay in the same wavelength use CWC2 developer PBQ rehalogenating bleach (Ed Wesly) - Replay is color shifted Pyro or CWC2 developer Dichromate reversal bleach ====PFG-03==== (Ed Wesly)- Replay is same wavelength use Slavich Hardener with G2 Developer and Slavich Fixer ====BB640==== (Ed Wesly)- Replay in the same wavelength use Pyrogallol based developer with Rehalogenating bleach b5cb77df2fb9ff0be3715c637250420362a0d19c 0 848 1813 1812 2013-05-12T04:08:22Z Jsfisher 1 1 revision wikitext text/x-wiki by Dinesh Padiyar Silver Halide is the most common holographic material currently used by everyone from hobbyists to professional scientists. This is because of its high sensitivity and the fact that it’s easily available commercially. Silver Halide is a salt of Silver and a Halide, which are a group of elements that include Fluorine, Chlorine, Bromine and Iodine, which are light sensitive. The first, accidental, discovery of the light sensitive properties of Silver salts came in 1727 when J Schulze mixed chalk, Nitric acid and Silver in a flask. He noticed that the side of the flask turned toward the sun turned dark. The first deliberate application of this effect, a photograph of a scene, was carried out by Niepce in 1827. This was a long exposure of about 8 hours. In 1841 Henry Fox Talbot patented a “calotype” process which made a permanent negative image on paper soaked in Silver Chloride. The present day emulsion was created by Richard Leach Maddox, who proposed using gelatin and Silver Bromide in what he called the “dry plate process”. Shortly after that Eastman Kodak coated a flexible film with this as a thin emulsion, mass produced it, and launched large scale photography. Silver Bromide is only sensitive in the UV and blue regions and so dyes need to be added to it in order to make it sensitive to other colors. In holography, specific dyes are added to give the emulsion a high sensitivity at particular, commonly available laser lines. Commercial SilverHalide materials consist of crystals, or ''grains'', of Silver Halide dispersed in a layer of gelatin, each grain consisting of many thousands of molecules of Silver Halide. When exposed to light individual molecules of Silver Halide on those grains that were illuminated break down to Silver which, due to it’s small size, appears black. Since the number of molecules of Silver Halide that convert to Silver on any one grain depends on the intensity of light hitting the grain, the darkness, or density, of any one grain depends on the light hitting it. Thus the emulsion converts the variation of light that hits it, the ''exposure'', to a density variation. After exposure the emulsion consists of exposed and unexposed Silver Halide grains. The action of converting the exposed emulsion to the same variation of density as the variation of light intensity at exposure by amplifying the exposed grains of Silver Halide is known as ''processing''. The removal of the unexposed grains is known as ''fixing''. Thus the entire process consists of exposure, development and fixing. There is also a bleaching step that is no longer widely used in photography but is common in holography. The fixing step is sometimes omitted. == Exposure == The exposure of an emulsion refers to the total amount of light energy that has hit it over a given period of time, the ''exposure time''. In holography, this is referred to as the ''sensitivity'' or ''speed'' of the emulsion and is given in terms of Joules/sq meter. However, due to the extremely high sensitivity of Silver Halide emulsions, this is usually given as microjoules/sq cm. This is the amount of energy necessary in order to produce a certain variation of darkness in the emulsion that faithfully maps the light that hit it. Too much exposure and the entire film goes black, too little and there is little or no variation of darkness. Factors important for exposure are the ''resolving power'' of the film and the contrast. The resolving power of a film determines the smallest detail that the film can captured. In holography, these details are in the order of a micron and so holographic film needs to have a very high resolving power. This resolving power depends on the size and distribution of the individual grains in the emulsion, referred to as the ''granularity''. In photographic film, the size of the grains may be about a micron whereas in holography it’s usually about 50 nanometers. As the grains get smaller, the sensitivity decreases, i.e. it takes a longer exposure time to create the same density variation. Another factor that affects resolving power is the ''scattering'' within the emulsion. This refers to the fact that the light entering the emulsion is scattered into random directions by the grains themselves. This randomly scattered light will affect nearby grains and so will decrease the resolving power. A measure of this resolving power is given by a curve plotting density against the logarithm of the exposure, known as the Hurter and Driffield, or H&D curve. The slope of this curve is known as the ''gamma''. Typical values of gamma for standard photography are about 0.7 while high contrast film has a gamma of about 1.5. In holography, it is necessary to have a gamma of at least 2. After exposure, the emulsion contains an invisible image called the ''latent image'' in which some of the grains in the emulsion were exposed to light and some were not. These exposed, latent image grains are distinguished from non-exposed grains by the their ability to be reduced to elemental Silver by the developer. == Development == All the grains in the emulsion consist largely of Silver Bromide with a few atoms of free, elemental Silver, called ''sensitivity specks''. These Silver specks contain about 1/10,000,000 of the mass of the whole grain. When a particular grain is exposed to light, some of the Silver specks on it are ionised by the release an electron. These Silver ions cause neighbouring Silver from nearby Silver Bromide molecules on the grain to also reduce to elemental Silver and hence the speck grows to form a larger latent image-speck. When the speck has grown to a particular size, it provides a point at which the developer can attack the grain. Grains which have not been exposed to light will still have specks, but with no ionisation of the specks, they will not grow sufficiently to form development centres. Developers consist of the following components: ; Developing agent : The developing agent is responsible for the reduction of all the Silver Bromide in the entire exposed grain into Silver, these grains being differentiated from the unexposed ones due to the presence of latent image specks. This results in an enormous amplification of the latent image by a factor of about 10,000,000. This is due to the fact that the mass of Silver in the original, undeveloped latent image speck was only about 1/10,000,000 th of the mass of the grain. Development causes the entire grain to convert to Silver. The developing agent is an organic reducing agent with a benzene ring-type structure. ; Preservative : Developing agents tend to oxidize rapidly when exposed to air making them ineffective. To prevent this, a preservative is added. Usually this is Sodium Sulphite but sometimes Potassium Sulphite is used. As the sulphite concentration is increased, the developer lasts a longer time. However, if too much sulphite is added, the emulsion may fog. ; Accelerator : Developing agents only work when they are alkaline, with increasing activity as the alkalinity increases. An accelerator is an alkaline compound that activates and accelerates the developing action. The accelerators are classed as strong, medium and weak. The stronger the accelerator, the more rapid the development while weak accelerators tend to balance out contrast. Strong accelerators include hydroxides, such as Potassium Hydroxide, medium accelerators include Carbonates, such as Sodium Carbonate. ; Restrainer or Anti-foggant : Some developers tend to attack unexposed grains which causes fog in the emulsion. To prevent this an antifoggant, or restrainer, is added. The most common restrainer is Sodium Bromide. Some low alkalinity developers may not need restrainers. == Fixing == After development the emulsion consists of grains of Silver, formed by the reduction of exposed Silver Halide, and unexposed Silver Halide grains. Fixing removes these unexposed Silver Halide grains rendering the emulsion inert to further reactions from light. The fixer is a solution of Sodium Thiosulphate which converts the Silver Bromide into Silver Thiosulphate and a few other ions. Ammonium is used in place of Silver in Rapid Fix due to the stronger solvent action. Of Ammonium Thiosulphate. The Silver Thiosulphate is very soluble in water and washes out of the emulsion and into the fixing bath. However, if the concentration of the Silver ions in the fixing bath is too high other, less soluble, Silver salts are formed. These can cause a yellowing of the emulsion. Commercial fixers also include a weak acid, usually acetic acid, to stop the action of the developer. The pH of the fixer is then about 4 or 5. If the pH decreases to too low a value (ie it becomes too acidic), the acid attacks the Thiosulphate and releases free Sulphur, This free sulphur forms a suspension in the emulsion causing it to fog. A hardener is sometimes also added to prevent swelling and softening of the gelatin during the wash. This is accomplished by lowering the pH of the fixer by a suitable agent to a value of about 3. == Bleaching == Bleaching is the action of an oxidising agent on the Silver grains. The oxidising agent oxidises the Silver to a soluble salt, that can be washed. The purpose of bleaching a hologram is transform the reconstruction method of the hologram from one whose primary reconstruction method is by altering the intensity of the reconstruction light - known as an ''amplitude hologram'' - to one whose primary reconstruction method is by altering the phase of the reconstructing light - known as a ''phase hologram''. In the former, amplitude-type hologram, the intensity of the (uniform) reconstructing beam is decreased as it passes through various parts of the hologram by an amount depending on how dark that particular part of the hologram is. The image is therefore dependent on the variations of the intensity of the reconstruction beam which is a map of the darkness variation of the plate. In the phase-type hologram, the hologram is completely transparent but either its thickness or its density varies at different points of the holographic medium thus altering the refractive index at that particular point. This variation of index alters the optical light path of the reconstruction beam as it passes through different parts of the holographic medium. In practice no hologram is ever completely of one or the other type, but a mixture of the two. This variation of index in a medium is known as ''phase variation''. It has been shown that the brightness, or ''diffraction efficiency'', of an amplitude hologram cannot exceed 33% while a phase hologram can be 100% efficient. However when a Silver Halide hologram is developed it is, by default, an amplitude hologram, due to the fact that the developer’s action varies the density of the medium. It would therefore be advantageous to convert the amplitude hologram to a phase hologram. This is done by a bleach which makes the entire holographic medium transparent and transforms the density variations of the medium into index variations. There are essentially two types of bleaches - reversal and rehalogenating. In reversal bleaches, the exposed, Silver grains are converted into a soluble complex and washed out in the bleach bath leaving the unexposed Silver Halide grains left in the emulsion to carry the holographic image. In this case, it’s necessary not to fix the hologram after developing since the loss of the unexposed Silver Halide would leave nothing in the emulsion. A reversal bleach bath consists of an oxidising agent , a buffer and sometimes other additives such as dyes. In rehalogenating bleaches, the reduced Silver grains are re-converted back to Silver Halide. Rehalogenated bleaching can be carried out on either fixed or unfixed holograms. In the fixed rehalogenating case, the unexposed Silver Halide is fixed out and the rehalogenating bleach converts the exposed Silver back to Silver Halide. In unfixed rehalogenation, the unexposed Silver Halide grains are still present after the bleach converts exposed Silver grains to Silver Halide grains. The difference between the two, necessary to distinguish image from non-image, comes from the fact that rehalogenated Silver Halide grains are larger than the original unexposed Silver Halide grains. One consequence of the increased size of the grain is that there is an increase in noise since scattering is dependent on, and increases with, larger grain sizes. A rehalogenating bleach bath consists of an oxidising agent, an alkali halide, a buffer and sometimes dyes. == References == ''Silver-Halide Recording Materials'' H. I. Bjelkhagen ''Topics in Applied Physics'', vol 20. "Holographic Recording Materials" ed H. M. Smith 9dda31099133859815176255809ea3f1774a68e3 0 507 1815 1165 2013-05-12T04:08:22Z Jsfisher 1 1 revision wikitext text/x-wiki This is a collection of chemistries for holographic development and holographic film manufacture. For the definitive source about holographic development please purchase a copy of SILVER HALIDE MATERIALS FOR HOLOGRAPHY AND THEIR PROCESSING by Hans Bjelkhagen ISBN 3-540-58619-9. Contact Integraf for JD-2, JD-3, JD-4, SILVER HALIDE MATERIALS AND THEIR PROCESSING by Hans Bjelkhagen or for Slavich Film. Many of these chemicals are very dangerous. Please don't breath the dust or fumes. Make sure to wear gloves and don't pour the used chemicals in your drain. Your drain goes to someone's drinking water! Don't forget to read and follow the MSDS. ---- Notes on Mixing Chemistry for Silver Halide Materials The order and methods you use for mixing is very important. Normally you add in the order of the formulation. Some of these formulations are likely to be out of order. ---- =TJ1= [[TJ1 Developer]] - By Jeff Blyth =JD-2= from Integraf for PFG-01 from Slavich Solution A *Distilled Water 100 Deg. F 750 ml *Catachol 20 grams *Ascorbic Acid 10 grams *Sodium Sulfite 10 grams *Urea 75 grams *Water 68 Deg. F 1 liter Solution B *Distilled Water 100 Deg. F 800 ml *Sodium Carbonate, Anhyd. 60 grams *Water 68 Deg. F to make 1 liter Mix equal parts A and B just before development. Mix enough for one hologram only. ( I have developed 3, But the first one is best) Bleach *Distilled Water 68 deg. F 750 ml *Potassium Dichromate 5 grams *Sodium Bisulfate 80 grams *Water 68 deg. F to make 1 liter Dissolve potassium dichromate completely before adding sodium bisulfate. The bleach can be used for a long time. At least 5 months shelf life. *Develop 2 minutes *Rinse 3 minutes *Bleach till clear (less than two minutes) *Rinse *Photo flo *Air dry =JD-3= from Integraf Developer Part A *Water 750ml *Catechol 20g *Ascorbic acid 10g *Sodium sulfite 10g *Urea 75g *Water to make 1L Part B *Water 750ml *Sodium carbonate 60g *Water to make 1L Bleach *Water 750ml *Copper sulfate 17g *Potassium bromide 55g *Succinic acid 2g *Water to make 1L Post Treatment *Water 300ml *Ascorbic acid 10g *Water to make 400ml Mix equal parta A and B. Working solution has a life of 8 hours. Only develop one hologram. Develop for 2 minutes with agitation. Soak in distilled water for 10 seconds. Wash for 3 minutes. Do not dilute bleach. Bleach emulsion side down till clear. Less than 2 minutes. Wash for 3 minutes. Dilute post treatment 1 to 10 with water. soak under bright light untill the hologram turns from pink to light brown. Wash for 3 minutes. =JD-4= from Integraf for PFG-03M from Slavich Developer Part A (1 liter)Quantity *Metol or Elon (p-Methylaminophenol sulfate) 4 g *Ascorbic acid (powder) 25 g Developer Part B (1 liter) *Sodium carbonate, anhydrous 70 g *Sodium hydroxide 15 g Bleach (1 liter) *Copper sulfate (pentahydrate) 35g *Potassium bromide 100g *Sodium hydrogen sulfate crystals 5g Mixing instructions Use three l liter (or larger)size clean glass or plastic bottles with leak proof caps. Label them A, B, and Bleach respectively. Warm the distilled or de-ionized water to about 40o C (warm to the touch). Fill the bottle marked A with 700 ml of warm water. Dissolve the Metol in it, then add the ascorbic acid. Add 300 ml of warm water to make 1 liter of Part A developer. Tightly cap the bottle. Part A will oxidized if it is exposed to oxygen. In time (over a few days to few weeks), the solution may turn yellow due to the oxidation of ascorbic acid; the solution is still useable. Once the solution turns dark brown, the potency is lost and should be disposed. One way of protecting it from oxidation is to subdivide the solution into smaller bottles so that the unused portions are in fully capped bottles, with little or no air space on top. Refrigeration also slows down oxidation (exercise extreme caution to prevent its mistaken identity as food). Follow the same procedure for Part B (add the sodium carbonate and sodium hydroxide in either order). This solution will keep for many weeks. Follow the same procedure for mixing the Bleach. This solution has very long shelf life. =Hardener - Slavich= Formalin 37% 10ml Potassium Bromide 2g Sodium Carbonate 5g Water to 1L =Fixer - Slavich= Methyl Phenidone 0.2g Hydroquinone 5g Sodium Sulphite(Anhyd.) 100g Potassium Hydroxide 5g Ammonium Thiocyanate 12g Water to 1L =Metol-Ascorbate developer= courtesy of Laser Reflections The formula is as follows: Metol-Acorbate Developer (Part A + Part B) Part A: *Metol 10g *Ascorbic Acid 80g *Water to 1000ml Part B: *Sodium Carbonate Anhydrous 120g *Sodium Hydroxide 14g *Potassium Bromide 4g *Water to 1000ml Use it in combination with a Fe-EDTA bleach - a safe, stable bleach which has a long shelf life. =Fe-EDTA Bleach= *EDTA (2Na) 30g *Fe(III) Sulfate 30g *Potassium Bromide 30g *Sodium Hydrogen Sulfate Crystals 30g *Water to 1000ml =Russian Emulsion Tips= From Jeffrey: When using Russian emulsions - Pre-develop gelatin hardening bath - Sensitizes and maintains colors, allows squeegee use *Distilled water 750 ml *Formaldehyde 37% (Formalin) 10 ml (10.2 g) *Potassium bromide 2 g *Sodium carbonate (anhydrous) 5 g *add distilled water to make 1 L Processing time 6 minutes. Developing times may increase with harder gelatin. =CWC2= From Jeffrey: CWC2 DEVELOPER and PBU-AMIDOL BLEACH - for all types of HOLOGRAMS CWC2 - two-part DEVELOPER PART A solution *500 ml. warmed distilled water. *(Pyro)Catechol 10 grams *L-Ascorbic Acid (Vitamin C) 5 grams *Sodium Sulfite (anhydrous) 5 grams *Urea 30 grams PART B solution *500 ml. warmed distilled water. *Sodium Carbonate 30 grams Part A is good for one month, Part B indefinitely. Add equal parts A & B to activate just a minute or two before use, just enough to cover one hologram. Mixed solution is active for 20 minutes. Discard after one use to assure each hologram has optimum development. Develop time:at least TWO minutes @ 68 degrees F. with constant agitation (AGFA). FIVE minutes for low power lasers, for HRT plates and PFG-03M plates. Rinse in distilled water. View a green safelight through rinsed plate to judge density - some variation is OK. Adjust exposure/developing time to achieve a final developed density of: *D 1.5 - 2 - medium gray (for an unbleached transmission hologram) *D 2 - 3.5 - very dark (reflection holograms). *D 4 - appears mostly opaque (good for HRT reflection holograms). Do not use fixer if it will be bleached (reflection holograms are usually bleached). Notes on developed density - this stage is where you figure if exposure, ratio, gleam spots, beam centering, even illumination, and overall light levels and their recorded patterns are OK for the next shot as well, or need adjustment. After the plate is bleached clear, these clues are gone. Although dark, wet, and hard to see, observation of different gray levels is important, hopefully understanding what caused each visible pattern. A good safelight is important. My favorite is a commercially available four-foot fluorescent fixture with plastic tube filters. =PBU-AMIDOL re-halogenating BLEACH= (Phillips Bjelkhagen Ultimate) *Potassium Persulfate 10 grams *Sodium Bisulfate (or Citric Acid) 10 grams *Potassium Bromide 20 grams *Cupric Bromide 1 gram *Amidol (- add last ! -) 1 gram Mix one at a time, in sequence, into 500 ml. warmed distilled water, then add another 500 ml. distilled water to make 1 liter. *Wait at least 30 minutes for chemical activation. *Bleach unfixed plate for 3-5 minutes @ 68 degrees F. 'til clear + 2 minutes. Rehalogenating (and image brightening) continues after clearing. *Rinse, rinse, rinse in distilled water. *With a drop of Photo-Flo in the final rinse, squeegee. *Air dry, a low-heat blower or drying cabinet for around 15 minutes - not too fast, not too slow. An acetic acid rinse after bleaching may help reduce print-out (the emulsion will darken a bit after you run out in the daylight to see your image). I prefer to avoid intense sunlight until aged a few days. Re-bleaching later will partially clear a darkened plate and give some immunity to further print-out. Bleach can be re-used a few times, and is usually good for two weeks - red color will fade to clear, indicating exhaustion. *Beware sediment as it ages - do NOT attempt to re-mix before each use - decant and do not dump dregs out onto emulsion. *Bleach will leave permanent purple stains on everything - handle carefully ! Many thanks to Cooke and Ward, Hans Bjelkhagen, Nick Phillips and Ed Wesly for the many trials to attain the basic formulation. -------------------------------------------------------------------------------- =GP-9= *Phenidone .026 g *Hydroquinone .665 g *Anhydrous Sodium Sulfite 13 g *Potassium Hydroxide 1.38 g *Ammonium Thiocyanate 3.12g *Distilled Water 1 L =GP-61= Transmission *Distilled Water 700cc *Metol 6 g *Hydroquinone 7 g *Phenidone .8g *anhydrous sodium Sulfite 30g *Anhydrous Sodium Carbonate 60 g *Potassium Bromide 2 g *Sequesterine Agent 1 g *Water to make 1 L =GP-62= Reflection (use Bleach) Part A *Distilled Water 700 cc *Metol 15 g *Pyrogallol 7 g *Anhydrous Sodium Sulfite 20 g *Potassium Bromide 4 g *Sequestrene Agent 2 g *Water to make 1 L Part B *Distilled Water 700 cc *Anhydrous Carbonate 60 g *Water to make 1 L =Kodak D-8= *Ascorbic Acid 18g *Sodium Hydroxide 12 g *Sodium Phosphate Dibasic 28.4 g *Distilled water 1 L Just before use add Phenidone .5 g =Transmission bleach= *Water 1 L *Potassium Ferocyanide 1 tablespoon *Potassium Bromide 1 tablespoon *or *Cupric Bromide 1 tablespoon (not both!) =Reflection bleach= *water 1 L *potassium Bromide 30 g *Borax 15 g *Potassium dichromate 2 g Just before use add PBQ (p-benzoquinone) 2 g (good for 15 minutes) =PBQ= *Water 1 L *Mercuric Chloride 1 tablespoon *Potassium Bromide 1 tablespoon or *Water 1 L *Potassium Bromide 30 g *Boric Acid 1.5 g *PBQ 2 g Good for only 15 minutes! or *Sulphric acid 1 g *potassium Bromide 5g *Methyl Paraben 2g *Hydrogen Peroxide 4 g (you have to figure the weight of the Hydrogen peroxide in you solution!) *Potassium Alum 5g (hardener) *PBQ 1 g *Phenosafranine 1g (desensitizer) =GP-431 Bleach = *Water 600 cc *Ferric Nitrate 8-hydrate 150 g *Potassium Bromide 30 g *Dissolve .3 g of Phenosafranine in 250 cc of methanol and then add. *Water to make 1 L Dilute 4 parts water to 1 part gp-431 before use. =Leroy= by Martin Since some are interested in the old Leroy paper, here is my - rudimentary - translation: Excerpts from: M.N. Leroy, Préparation et sensitométrie de plaques photographiques à grain très fin (plaques pour la photographie interférentielle), Paris 1929 ==== Summary ==== The following note presents a new way for the making of fine grain photographic emulsions, derived from colloidal silver, that allows for the spectral recording of remarkable brightness, comparable to Lippmann emulsions. It (the note) summarizes certain results achieved with silver chloride, bromide and iodide. The study of the density graphs indicates a maximum sensitivity at a particular lambda for each of the three cases and depends on the molecular weight of the specific salt used. Having established the characteristic graph of each emulsion at certain spectral levels, the author is studying the variation of gamma as a function of lambda, and points out that these plates, (though) having the qualities of any common plates, they can be sensitized to any wavelength and t can be used for color photography. The present study tried to establish the sensitometric characteristics of Lippmann plates, prepared according the formula of the ingenious inventor of the only direct recording method of color photographs. The results indicated too many variations and lacked the desired consistency. This is certainly due to fluctuations usually occurring (even) with the same composition (differing but on agitation, temperature, filtering, washing etc.). In one case, instead of being sensitive to the wavelength showing the strongest diffraction, we even observed sensitivity to radiation all over the visible spectrum. Without adding any sensitizers, it all the same behaved like an orthochromatic plate and, this was consistent for all plates of that batch, we do not have an explanation. According to Mr. Cotton, who advised us to use colloidal silver, on which grounds he had managed to make plates for interference color photography, we succeeded to get light sensitive layers of very small grains and of great consistency indicated by the measurements we carried out in the case of silver chloride, bromide and iodide. ==== Preparation of the plates ==== To a tepid solution (filtered warm) of 2.5g special gelatin in 50 cm3 distilled water, 3 cm3 of a 10% colloidal silver solution are added. The resulting liquid of brown color, is poured on glass plates according to the methods used for collodion. The plates, arranged horizontally until gellation, are subsequently dried protected from dust. These operations are carried out under normal light, thus allowing for the production of a stock to be used occasionally as needed. The transformation of the colloidal silver into halide salts is carried out under subdued light, such as that of a candle or some reduced gaslight. The plate is introduced into a bath for which - after numberless trials - we established the following compositions (note: the quantities given do not correspond with the completed reaction but proofed to work most conveniently for our experiments): {| class="wikitable" |+Chloride plates |- |align="left"|sodium chloride||align="right"|2g |- |align="left"|copper sulfate||align="right"|2g |- |align="left"|water||align="right"|1000g |} {| class="wikitable" |+Bromide plates |- |align="left"|potassium bromide||align="right"|2g |- |align="left"|copper sulfate||align="right"|2g |- |align="left"|water||align="right"|1000g |} {| class="wikitable" |+Iodide plates |- |align="left"|potassium iodide||align="right"|2g |- |align="left"|copper sulfate||align="right"|2g |- |align="left"|water||align="right"|1000g |} "Bromination" is taking place equally well by using a diluted solution of cupric bromide; cupric chloride however, produced an opaque layer as well as did chlorine water (?) or iodine solution. During the preparation of the iodine (? rather cupric iodide I suppose - MM) bath, a precipitation of cupric iodide is forming which can be eliminated by filtering. As soon as the reaction stops - that is to say, when the yellowish color has vanished - one has to wash the plate, turned transparent meanwhile, exhaustively. At this stage the plates are very little sensitive. A means to this nuisance is to insert them into a second bath of 50g water to which 2g of a silver nitrate solution (0.5g AgNO3 per 100g water) were added during 1 minute. They are washed with distilled water and dried in darkness. The developer has the following composition: {| class="wikitable" |- |align="left"|water||align="right"|100ml |- |align="left"|sodium sulfite||align="right"|4g |- |align="left"|Amidol||align="right"|0,3g |- |align="left"|Potassium bromide||align="right"|0,75g |} The plates are fixed in sodium thiosulfate. ==== Conclusions ==== Due to the preliminary results, this study represents only some sort of beginning. Nonetheless, we are thinking the constants (?) introduced by Hurter and Driffield into photographic practice, can be applied to the fine grain plates we prepared. We will continue our work, systematically studying the use of chemical sensitizers and try to realize a perfectly orthochromatic "interference" plate. We meanwhile like to point out that the silver bromide plates prepared by flowing, are easily sensitized orthochromatically and allow for spectral recordings of the same brightness as Lippmann plates. The same is also valid for chloride. However, the sensitizers ("orthochromatisants") successfully applied to chloride and bromide, did not show any effect on iodide. Concluding this work, it is an pleasant duty to express my appreciation to professor Cotton (directeur du Laboratoire des Recherches physiques à la Sorbonne), for his support and interest. I equally thank my teacher, Mr. de Watteville, who introduced me into the delicate technique of interference photography... etc. =Making your own plates= by Jeff Blythe Diffusion method - estimated cost by Jean (no login) As promise, I post my estimated costs table for a batch of 20 holoplates made with the Jeff Blyth's diffusion method. Silane, LiBr, Pinacyanol come from Sigma-Aldrich All prices are in Euro (1 Euro ~ 0,97 USD) {| border="1" |- !Chemical !Price/Quantity !Diluted quantity !Quant/20 plates !Price/20 plates |- !AgNO3 (6%) |align="right"|18,11/10 g |align="right"|166 ml |align="right"|60 |align="right"|6,55 |- !LiBr (3%) |align="right"|11,2/100 g |align="right"|3300 ml |align="right"|300(*) |align="right"|1,02 |- !Pinacyanol (0,1%) |align="right"|16,81/250 mg |align="right"|250 ml |align="right"|7,5 |align="right"|0,5 |- !Ascobic Acid (1%) |align="right"|2,11/30 g |align="right"|3000 ml |align="right"|300(*) |align="right"|0,21 |- !Gelatin (15%) |align="right"|9/1000 g |align="right"|6666 ml |align="right"|100 |align="right"|0,14 |- !Chrome Alum (2%) |align="right"|3/100 g |align="right"|5000 ml |align="right"|300(*) |align="right"|0,18 |- !Silane (1%) |align="right"|31,16/100 ml |align="right"|10000 ml |align="right"|100 |align="right"|0,31 |- !Glass (4x5) |align="right"|12,5/20 |align="right"| - |align="right"|20 |align="right"|12,50 |} Total for 20 plates - - - 21,41 or 1,07/plate (*) I assume I change for each batch : - LiBr + Dye bath - Chrome Alum hardener - Ascorbic Acid sensitizer But please pay attention of this following note from Jeff about the LiBr bath : "please note that I myself reuse the dye/LiBr baths several times. A little bit of precipitate in the bottom of container (it is only AgBr) can be left there and the liquid poured off or the solution just filtered. So you can make many plates if you want to for the initial expence. The quantity of subbed plates you could make is enough for an industrial production run!" I don't calculate price for water, acetone and methanol because those products are cheap. First batch can seems expensive because you need to purchase relatively big quantity in regard of the used quantity and you need to some laboratory material. Hope this can give you the curiosity to test this easy method. Jean PS : my 2nd batch has failed because I don't care to dry plates enough after Chrome Alum bath! Results was presence of chrome salt who fog the plates. I'll try hardening gelatin with a bath of 1% formalin in DI water. =SM-6= *Sodium Hydroxide 12.0g *Methyl Phenidone 6.0g *Ascorbic Acid 18g *Sodium Phosphate (dibasic) 28.4g *Water to 1L =Stop Bath= *Acetic Acid 20g *Water to 1L =Safe Ferric Brilland Bleach= ( rehalogenating Bleach designed by brilland) *Ferric III Sulfate 30g *Citric acid 30g *Potassium Bromide 30g *Deionized water to 1000 cc. You can use it and store it for a very long time at room temperature. It gives very low noise results. =AAC= *Ascorbic Acid 18g *Sodium Carbonate to give a pH of 10.5 *Distilled Water 1L =AGFA 80= *Metol 2.5g *Soduim Sulfite (anhydrous) 100g *Hydroquinone 10g *Potassium Carbonate 60g *Potassium Bromide 4g *Distilled Water 1L =GP-8= *Metylphenidone .2g *Hydroquinone 5g *Sodium sulfite (anhydrous) 100g *Potassium hydroxide 10.6g *Ammonium thiocyanate 24g *Distilled water 1L Mix 60 ml of developer with 400ml of distilled water. Develop for 6 minutes at 20C. =GP-2= *Metylphenidone .2g *Hydroquinone 5g *Sodium sulfite (anhydrous) 100g *Potassium hydroxide 5g *Ammonium thiocyanate 12g *Distilled water 1L Mix 15ml of developer with 400ml distilled water. Develop for 12 minutes at 20C without agitation. Develop with plate facing up and DO NOT agitate (you don't want to move the disolved silver away from the plate). =CPA1= *Metylphenidone .02g *Hydroquinone .65g *Sodium sulfite (anhydrous) 13g *Potassium hydroxide 1.4g *Ammonium thiocyanate 3.1g *Distilled water 1L Develop for 2 minutes at 22C. 3 seconds of initial agitation. =N6= *Metol .5g *Sodium Sulfite (anhydrous) 100g *Hydroquinone 45g *Sodium carbonate 30g *Potassium thiocyanate 5g *Potassium bromide 10g *Distilled water 1L Mix 1 part developer to 8 parts distilled water. =F1= *Amidol 4g *Sodium sulfite (anhydrous) 30g *Silver nitrate 3g *Potassium bromide 2g *Sodium thiosulfate 45g *Distilled water 1L Develop for 8 minutes. Fix for 2 to 3 minutes. =F2= *Metol 10g *Sodium sulfite (anhydrous) 100g *Silver nitrate 2g *Potassium bromide 2g *Sodium thiosulfate 30g *Distilled water 1L Develop for 30 minutes. No fix is required. =MM-Collo 1= From Martin: The best formula I ever made for a colloidal developer was: *Metol.............................2g *Ascorbic acid.....................7g *Methylphenidone.................0,5g *Potassium bromide.................3g *Potassium carbonate..............20g *Ammonium thiocyanate..............2g *Distilled water...................1L Dilute 1 : 50 or up to 1:100 (with distilled water) On PFG-03M it yielded extremely fine grains, resulting in a yellow emulsion (compared with the orange/red layer produced upon GP development). Development is quite slow, requiring > 30 min @ 20°C. =VR-P developer= *Sodium Sulphite anhydrous 194 g *Hydroquinon 25 g *Potassium Hydroxide 22 g *Methylphenydone 1.5 g *Potassium Bromide 20 g *Potassium Metaborate 140 g *1,2,3-Benzotriazole 0.1 g *Distilled water to 1 L Working solution: 1 part of VR-P Developer + 6 parts distilled water =Phillips' Ferric Nitrate Bleach= *150 g Ferric Nitrate *33 g Potassium Bromide *20 g Glycerol *300 mg Phenosafranine *500 ml Isopropyl *500 ml Distilled Water =Phillips' PBQ-1 Bleach= *2 g PBQ *30 g Potassium Bromide *1.5 g Boric Acid *1L Distilled Water =Phillips' Ferric EDTA= *30 g Ferric Sulfate *30 g Di-sodium EDTA *30 g Potassium Bromide *10ml Sulfuric Acid *1L Distilled water =D-14H= From Hans: I got this formula from http://silvergrain.com/labs/Print_Developer_Recommendation?title=Print_Developer_Recommendation It does not to be mixed in a A and B solution and I have found that it works just as good as the Ultimate safe holographic developer. I made on adjustment to the original formula in that I left the KBr out because I don't think that there should be KBr in a holographic developer. Development time is about 1.5 minutes. *Dimezone S 0.2g *ascorbic acid 6.0g *sodium sulfite, anhydrous 12.0g *sodium carbonate, monohydrate 30.0g *triethanolamine, 99% 5.0ml *salicylic acid 0.5g *water to make 1.0 liter target pH 10.4 ± 0.2 =Ascorbate Developer= But I contend that the best way of dealing with ascorbate developer stock and it is a way we have been successfully using for some years in our labs is to "A and B" it. For A we have a 500ml bottle with: *20g ascorbic acid *3g Metol (4-methylaminophenol sulfate) *and top it up with 500ml deionized water for B we have a 500 ml bottle of *50g sodium carbonate anhydrous *15g sodium hydroxide top up with 500 ml deionized water. (This one should be labeled "very caustic" ) Just use equal volumes of A and B from then on. Now there are 3 bonus points for using Metol instead of phenidone. 1) is that phenidone is quite a strong silver halide solvent and tests have proved that metol gives brighter holograms. 2)The second point is that metol has a hardening action on gelatin and its effect on speeding up the development time over what you would have with just alkaline ascorbate means that even notoriously soft emulsions juch as PFG-03 can be in and out of the developer bath into a stop bath (~5% acetic acid ) in around 20 seconds, before the gelatin is seriously attacked. Assuming of course your exposure level was good enough. 3) Metol is a weaker reducing agent or developer than alkaline ascorbic acid. When Metol gets oxidized it goes really dark brown so this is a useful indicator to tell you when your bath is exhausted because it wont go severely dark until most of the ascorbate has been oxidized. A mild yellowing like weak tea is quite OK . Dont forget to use the floating dish method of 2 closely fitting plastic dishes with the upper dish keeping most of the air out as it floats and acting as convenient agitator as well. Acid ascorbate in the stock soln A will not seriously oxidize for a year. (Slight yellowing is perfectly OK . ) jeff =Metol-Ascorbate developer courtesy of Laser Reflections= The formula is as follows: Metol-Acorbate Developer (Part A + Part B) Part A: Metol 10g Ascorbic Acid 80g Water to 1000ml Part B: Sodium Carbonate Anhydrous 120g Sodium Hydroxide 14g Potassium Bromide 4g Water to 1000ml Use it in combination with a Fe-EDTA bleach - a safe, stable bleach which has a long shelf life. Fe-EDTA Bleach EDTA (2Na) 30g Fe(III) Sulfate 30g Potassium Bromide 30g Sodium Hydrogen Sulfate Crystals 30g Water to 1000ml =Sergey Vorobyov's developer - OD-1= New postby Gall » Mon Nov 08, 2010 12:05 pm Some time ago Mr. Vorobyov invented a developer for silver-halide holograms that does not contain any rhodanides. It is ideal for both beginning and advanced holography. The original Russian article is here: http://www.holography.ru/tech8rus.htm Original formula: *Metol = 2 g *Sodium Sulphite (anhydrous) = 25 g *Hydroquinone = 5 g *Borax B[sub]4[/sub]H[sub]4[/sub]Na[sub]2[/sub]O[sub]7[/sub] = 2 g *Sodium Thiosulfate (photographic fixer) = 6 g *Water = 1000 ml Here sodium thiosulfate replaces rhodanide. It dissolves AgBr so that the process is the physical one and not the chemical one. Simplified formula - made from Kodak D-76, ideal for beginners (image is slightly worse but still works): *Take Metol and Hydroquinone mix from two ready-made 0.5l D-76 packages (2x[1 g + 2.5 g]). *Take Sodium Sulphite and Borax mix from one package (1x[50 g + 1 g]). *Add 6 g (one teaspoon) neutral fixer (Sodium Thiosulfate). This will result in following: *Metol = 2 g *Sodium Sulphite (anhydrous) = 50 g *Hydroquinone = 5 g *Borax B[sub]4[/sub]H[sub]4[/sub]Na[sub]2[/sub]O[sub]7[/sub] = 1 g *Sodium Thiosulfate (photographic fixer) = 6 g *Water = 1000 ml Dissolve Metol and Hydroquinone first in some warm (40-45 centigrades) water, then add everything else, add water to 1000 ml and filter the solution. The resultiong solution should be mixed with water 1:4 before use. Develop around 10 minutes at 18 centigrades. =Zip1= For transmission Holograms. I have been using my own developer for the last three years which is extremely active requiring much shorter exposure times than others (JD-2, JD-4, Pyro, etc). Used it for reflection and transmission on Slavich (especially VPR-M) and Agfa films and plates (8E75/56). Sometimes EDTA and sometimes Dichromates bleaches: Zip1: *Metol 1gr, *Hydroquinone 1gr, *Phenidone 0.5gr, *Sodium Sulphite 30gr, *Ascorbic Acid 10gr, *Potassium Hydroxide 30gr, *water to make 1 litre Dave I've used it for reflections in place of the pyro developer and with the dichromate bleach. It also over comes the hassle of accidently getting stained fingers with the pyro developer if you forget to put the rubber gloves on. The main benefit I've found is that the image brightness is on a par with the other developers with the bonus of shorter exposures. The mix of the Metol, Hydroquinone and Phenidone with the Potassium Hydroxide is quite an active combo. I'm not really surprised and certainly these chemicals are cheaper than pyro and catechol.. 6cadb9f85597c4313be29711a8033f108b907ab5 0 511 1817 1173 2013-05-12T04:08:22Z Jsfisher 1 1 revision wikitext text/x-wiki '''SOGOKON' A. B.''' '''LIPPMANN PHOTOGRAPH''' ON THE LAYERS OF THE BICHROMIZED GELATIN Are investigated the spectral characteristics of the Lippmann images, obtained on the layers of the bichromized gelatin (BKHZH). It is shown that the color of image depends not only on the wavelength of emission, but also on its intensity. This is connected with the heterogeneous swelling of gelatin and with a change of its structure in the nonirradiated sections with the rapid dehydration. The uncommon properties of Lippmann photographs on BKHZH can be used for preparing the selective mirrors, for mapping of graphic information, and also for registration and image processing. Is known [1] the method of obtaining the colored images, based on the registration of standing waves in the volume of thick transparent photographic emulsion. The period of the registered interference structure is unambiguously connected with the wavelength of that falling to the layer of emission, which ensures the correct color reproduction of the photographed image with the illumination by its white emission. Because of the great technical difficulties in its time this method did not obtain wide application. The development of holography led to the creation of the fundamentally new technique of experiment and new recording media. Appeared communications about the record of Lippmann photographs on the contemporary emulsions of the type LOI-2 [ 2,3 ] and on the layers of the bichromized gelatin (BKHZH) [ 4,5 ]. Purpose of this work - study of the special features of the Lippmann photographs, obtained on the layers BKHZH, the mechanism of shaping of images and possibilities of their practical application. '''Procedure and the results of the experiment''' For the preparation is layer BKHZH the basis it is undertaken the method Lina [6]. The holographic plates Of pe-2 and LOI-2 they fixed in the acid fixative, washed in the running water and dried at room temperature. The sensitization of the dried plates was conducted directly before the exhibition. For this plate was immersed on 5-15 min in 1-5%- ache the solution of dichromate of ammonium and after its runoff dried in the jet of hot air or in the cabinet drier at a temperature 100-150°. Duration of drying 3-5 min. [[Image:LippmannFig1.jpg]] Fig. 1. Installation diagram for the contact printing Lippmann photographs; 1 - luminous source (laser or mercury-vapor lamp), 2 - lens, 3 - negative, 4 - layer BKHZH, 5 - the mirror The installation diagram for the printing of Lippmann photographs is given in Fig. 1. They direct the extended laser beam to the negative, located before the recording medium, the passed emission is reflected from the flat mirror and, being extended in the opposite direction, is formed in the volume of the recording medium the standing wave, whose amplitude depends on the transmission of negative. As the radiation sources were used the lasers LPM-YY (442) and LIE -21 (337 nm) and mercury-vapor lamp DRSH-2SHCH0 (365, 436 nm). Furthermore, by means of the usual photographic enlarger was achieved the direct projection printing of enlarged images. The regime of working the plates exposed practically was differed in no way from the regime of working BKHZH for obtaining the holograms [ 7 ]. The images, obtained employing the procedure given above, have a number of interesting properties. With the examination of image in the reflected light (a subnormal incidence in the light) different sections of image depending on the density of initial negative acquire different color. Under the transparent sections is obtained the image of dark-blue color, while under the opaque - red. The semitones of negative are transferred by nuances within the limits from the orange to the green. Hence it is possible to draw the conclusion that the period of the interference structure, fixed in the layer BKHZH, depends both on the wavelength of emission and on its intensity. If we arrange Lippmann imprint on the sheet of black paper and to examine at large angle, then usual black and white image is observed. Under the transparent sections of the negative of gelatin it remains transparent, while under the opaque acquires milk-white tone. In this case the image is constructed not due to the luminous absorption, but due to its scattering, which resembles the properties of images on the vesicular materials [8]. For investigating the dependence of the color of image on the exposure level on one plate they achieved a number of exposures by the uniform collimated laser beam or photographed the image of sensitometric wedge, and then the spectra of the transmission of the obtained images were measured. [[Image:LippmannFig2.jpg]] Fig. 2. Characteristics of Lippmann the image: and, g - dependence of the spectra of the transmission of the images from the exposure level with the record by the emission heliumcadmium (442 nm) and nitric (337 nm) lasers; b and d - dependence of the density of image on the exposure for the same wavelengths; C - the dependence of the color of the image from the logarithm of exposure (curve 1 - 442, curve 2 - 337 nm); e - dependence of the half-width of the spectra of the transmission of the images from the exposure (1 - 442, 2 -337 nm) Fig. 2 depicts the spectral characteristics of the images, obtained on the plates Of pe-2, sensitized by the 1%- by the solution of dichromate of ammonium during the exhibition by the emission of lasers LPM-YY (Fig. 2, A) LIE -21 (Fig. 2, g). From the analysis of spectra follows that depending on exposure level the width of reflection spectra (Fig. 2,e) changes, the wavelength of the maximum of reflection (Fig. 2, c), and also the density of image (Fig. 2, b, d). It should be noted that the wavelength of the maximum of reflection with the long exposures does not correspond to the wavelength of the emission of record. This is connected with the fact that in the process of treating the layer an increase in the period of interference structure occurs. The wavelength of the maximum of reflection linearly depends on the logarithm of exposure (Fig. 2, c), which gives the possibility to write down [[Image:LippmannEq1.gif]] (1) where - the wavelength of the maximum of reflection with the high energy of exposure (wavelength of saturation), H - energy of exposure, k - constant of proportionality, which can be interpreted as the coefficient of the color contrast. With the conversion of the color of image occurs a change in its density (Fig. 2, b, d). These dependences are analogous to the characteristic curve of blackening of the usual recording media. However, the photographic latitude of linear section is considerably less, and in the field of the long exposures is observed the especially large spread of experimental points, which it is not possible to explain by error of measurements. It is possible to assume that the dependence of image in the region of saturation bears the oscillitory nature, for example, as shown in Fig. 2, d. '''Mechanism of the formation of the images''' In the process of the preparation of plates for the sensitization they prolonged time (about 1 h) find in the water. As a result of this gelatin it swells, long protein molecules untwist and they attempt to form the linear arrays. To molecules, which are been located on surface layer, this succeeds to the larger degree than for molecules, which are located in the depth, since they to a lesser degree experience the resistance of adjacent molecules. In the razbukhshem layer is obtained the heterogeneous tanning, which grows from surface layer to the base layer. The surface molecules of gelatin, which formed the linear arrays, no longer can accomplish work, they occupied energetically advantageous position, while molecules, which are located in the depth of layer, they have a certain reserve of potential energy, since interaction of some with others and with the molecules of tanning matter does not make possible for them to be erected into the linear arrays. Tanning can be determined by value, to the inversely proportional work, accomplished by molecules with the working in the water. Layer is not tanned, if molecules realize entire stored potential energy, and it is tanned, if potential energy with the working in the water does not realize. The potential distribution energy along the thickness of the razbukhshego layer can be schematically presented, as shown in Fig. 3, A. Let us examine the processes, proceeding with swelling of those exposed it is layer. In this case we consider that the photochemical transformations Cr(.VI) into S.r(.III) in the gelatin occur in accordance with the model, described in the work [ 9 ]. The number of photos-seam between the molecules, which were being formed in the antinodes of standing wave, is small with low energies of exposure, summary binding energy between them is also small, and the potential distribution energy of the molecules of the swollen layer takes the form, shown in Fig. 3, b. furthermore, with the prolonged working in the water together with swelling of layer in the knots of standing wave can occur the local dissolution of gelatin, i.e. the hydrated molecules acquire relative freedom, changing the structure of gelatin, but they cannot leave layer because of the tanned sections in the antinodes. In the works [ 10,11 ] it is shown that the structure of gelatin changes both with working of layer in the water and in the process of drying. Therefore with the working by isopropanol a change in the structure of gelatin in the knots and the antinodes occurs differently, i.e. with the rapid loss of water of molecule they do not manage to return to the initial state and they are forced to form the new molecular network, different from that, which is obtained with usual gel-NII - Scientific Research Institute or slow drying. In the knots of standing wave gelatin density decreases due to an increase in the volume of layer, while in the antinodes it increases due to structure change under the action of that forming Of s.r(.III). As a result of gelatin the elasticity loses, and in the layer the increased period of interference structure is fixed. With an increase in the exposure grows modulation of potential energy of the razbukhshego layer. The number of constant-phase surfaces, recorded in the layer, increases (Fig. 3, in, g, d), the width of reflection spectra and displacement into the red region decrease, and diffraction effectiveness rises. By a change in the structure of gelatin it is possible to explain the formation of black and white image. The destructured sections strongly scatter light, which gives milk-white form to them. '''Consideration of the results''' Uncommon properties of Lippmann photographs on the layers BKHZH can be used for preparing the selective mirrors, for obtaining the pseudo-colored slides from the black and white negatives, for registration and image processing. The possibility of using the Lippmann photographs as the selective mirrors directly follows from Fig. 2. The wavelength of reflection and half-width depend on exposure level. In this case the reflection coefficient attains 99%, which makes it possible to use such mirrors in the resonators of lasers, in the Fabri-Perot interferometers, and also as the beam splitters in the holographic devices. The cost of them is considerably lower than interference dielectric mirrors, and in this case is a possibility of preparing the mirrors of practically any sizes and creation of any distribution of spectral characteristics in the plane of mirror. [[Image:LippmannFig3.jpg]] Fig. 3. Diagram, which elucidates the dependence of the period of the interference structure from the exposure level: and - the distribution of the tanning in the razbukhshem unexposed layer; b, in, g, d - modulation of the tanning in the razbukhshem layer depending on the exposure The pseudo-colored slides, obtained from the black and white negatives, can be used for mapping of graphic information, for example diagrams, tables, graphs. Slides can be demonstrated both in the transmitted light by usual kadroproyektorom and in that reflected with the application of an epidiascope. The second version should be given preference, since with this more fully is used color range and is reached higher high-contrast image. With the printing from the black and white negatives the value [[Image:LippmannEq2.gif]] and [[Image:LippmannEq3.gif]] in equation (1) can be represented in the form [[Image:LippmannEq4.gif]] and [[Image:LippmannEq5.gif]] where - the intensity of light, which falls to the negative, the smallest density of negative (density of veil), density of image, time of exhibition. After substituting these values in (1), we will obtain [[Image:LippmannEq6.gif]] whence it follows that a change in the color in the Lippmann photograph is linearly connected with the density of negative. Recently increasingly more frequently is used the idea of complex spatial distributions of different physical quantities by means of the conditional it is color, for example, with digital processing of images [ 12 ]. To Lippmann photographs on BKHZH this property is inherent by their nature itself. In this case Lippmann "painting" has the advantage that the obtained image can be subjected to further optical working. Examining the pseudo-colored image through the light filter with the passband [[Image:LippmannEq7.gif]], we will observe the details of initial image, which are located in the density range [[Image:LippmannEq8.gif]]. By a change in the wavelength of light filter it is possible to separate the image details interesting, and by changing its half-width - range of densities interesting. If the image, observed through the interference light filter, photographed on the contrasting photographic material, then it is possible to obtain the images of the lines of identical density - equidensities. For the illustration is carry ouied processing the image of planet Jupiter. For this from the astro-negative they printed image with an increase by the layer BKHZH. The obtained image they photographed through the interference light filter with [[Image:LippmannEq9.gif]] = 640 nm and [[Image:LippmannEq10.gif]]= 90A. Fig. 4, and depicts the photograph of initial image, while on Fig. 4, b, C - to a series of photographs with the different angles of the slope of interference light filter, i.e. with the different [[Image:LippmannEq9.gif]] and [[Image:LippmannEq10.gif]]. It is evident that even under the conditions for the incorrectly set experiment (reconstruction of the wavelength of light filter was achieved via its inclination) on the obtained images it is possible to reveal more interesting details, than on the initial negative. [[Image:LippmannFig4.jpg]] Fig. 4. Isolation of equidensities on the image of planet Jupiter: and - the imprint of siskhodnogo astro-negative; b - photograph of the Lippmann image, obtained with the interference light filter with the different angles of its inclination in the reflected light; C - the same, but in the transmitted light However, with the two-stage process unavoidably are shown distortions and noise, which appear during the first stage of registration. The granularity of images on Fig. 4, b is caused by the granularity of the material, on which is registered initial negative. Therefore the considerably larger volume of information can be extracted with processing of the Lippmann images, obtained with the direct registration. However, sufficiently small sensitivity it is layer FOR BKHZH it does not make possible to directly record the images of other astros-object, except the sun. The direct registration of Lippmann images possibly in biology. In this case the emission of lamp DRSH-2SHCH0 it is completely sufficient for obtaining the images with increase in 30-100x. Thus, the Lippmann photographs, obtained on the layers BKHZH with the use of sources of monochromatic light, have properties, substantially different from the properties of usual Lippmann photographs. This is connected with the special features of the recording medium: the period of the fixed interference structure depends not only on the wavelength of incident radiation, but also on its intensity. As a result the possibility of the single-valued conversion of the intensity of light in the color appears. Simplicity of the diagram of obtaining Lippmann photographs, possibility of using the sources with the small length of coherence and high diffraction effectiveness of images open the great possibilities of the practical application of this method. In conclusion the author considers as his pleasant duty to express appreciation To v. p. sherstyuk and L. ye. mazur for the valuable considerations, in. By a. kaminskoy and By l. ye. nikishinoy for help in conducting of spectrophotometric measurements and V. n. dudinova - for the kindly furnished astro-negatives. '''LITERATURE''' *1. Lippmann G S. R// Acad. Sci. 1891. V. 112. P 274. *2. Kostylev G. d. //Pis'ma in ZHTF 1976. Vol. 2. Of iss. 23. S. 1086. *3. Kostylev G. d., Ivanenko L. i.// the theses of dokl. IV All-Union conf. "photometry and its metrological guarantee". M., 1982. S. 119. *4. Sogokon' A. V.// the theses of dokl. IV All-Union conf. "non and uncommon fo- tograficheskiye processes". Blackcap, 1984. Vol. 1 of h. 2. S. 251. *5. Sogokon' A. b.// the theses of dokl. II All-Union conf. the "forming of optical image and the methods of its working". Kishinev, 1985. Vol. 1. S. 125. *6. Lin L n.// Appl. Opt. 1969. V 8. № 5. P 963. *7. Sjolinder S// Photogr. Sci. And Eng. 1984. V 28. № 5. P 180. *8. Nagornyy V. i., Chibisova N. p. //ufn. 1978. Vol. 19. S. 32. *9. Sherstyuk V. p., Dilung I. I. In the book: Fundamental bases of the optical of pamya- TI and medium. Kiev: Vishcha shk. 1982. Iss. 13. S. 33. *10. Levi S. m., Suchkova O. m., Suvorin V. V.// the jour. of nauch. and appl. photo- and kinema of tografii. 1984. Vol. 29. № 4. S. 252. *11. Murzinov A. V., Moiseyeva G. V., Stryukova e. g. and other// theses of the report republic of se- of minara "applied holography". Kiev, 1984. S. 49. *12. Usikov A. 4., Babichev A. A., Yegorov a. d., etc.// to conduct. AN OF UKRCSSR - UKRAINIAN SSR. 1977. № 10. S. 47. Kharkov state university im. a. M. of Gor'kiy 25c7666842e7392e25efaaaf5cbb3400fceb0244 0 514 1821 1179 2013-05-12T04:08:23Z Jsfisher 1 1 revision wikitext text/x-wiki Some emulsions are harder than others. Harder emulsions can take squeegeeing better than softer ones. BB-640 and PFG-01 are pretty hard and sqeegees well; Ultimate and PFG-03 are pretty soft and easily scratched. *Squeegeeing works better when a wetting agent is used. Photoflo works well, but some think it may contribute to printout. Others use the Ilford product, or just a drop of liquid soap in the final rinse. *You didn't say if you were using plates or film. For film, use a piece of clean glass to support it. Stick the film to the glass emulsion side down a la index matching and squeegee the back. The remove the film, squeegee the glass dry, and stick the film back onto the glass emulsion side up and squeegee that side last. *For glass plates, the sharp edge of the glass will make cuts in the rubber blade, which will leave streaks next time. To minimize this problem, make a jig that keeps the wiper blade in the same position relative to the plate every time. This way the cuts will always be close to the edge of the glass. 15cee72873159d5a455057f4378ac46d1f7d9785 0 850 1823 1822 2013-05-12T04:08:23Z Jsfisher 1 1 revision wikitext text/x-wiki All of us know something about gelatin and the way it ages and holds up in various environments. It is present in many foods we eat and in leather and furs we wear. It is a fibrous felt like substance made up of dozens of amino acids arranged in long polypeptide chains. In leather it has been tanned for strength and lubricated to better stand the flexing. In photographic films it has also been tanned or cross linked to resist abrasion and absorption of water which would cause it to swell and become very soft and perhaps a meal for micro-organisms. In holographic phase only films the degree of hardness plays a key role in determining the clearness of the gel after it has undergone rapid dehydration. We begin to harden it first by cooking it for several hours with water vapor present, then by continued dark reaction with chromate ions, then by exposure to actinic or blue radiation to harden a pattern into it, then through a low ph bath of water and salts such as Kodak fixer with hardener and finally with a post process dry bake out at temperatures up to 120 deg C . This last treatment will increase the density of the film and decrease the legendary affinity it has for water vapor, but it is still far from water proof. ==Hologram formation in gelatin== A DCG hologram is first formed optically by absorbing light and cross linking at the sites where the light is most intense. Then the whole film is swollen in water with the most heavily exposed regions swelling a little less than the unexposed or lightly exposed regions. At this point we have a dimensional magnification of the original fringe pattern where the water has decreased the density of the gel periodically corresponding to the original interference pattern. If it were possible to dry the film at this point without having it change dimensions then there would be a very large difference in the densities of light and dark areas which translates into a large change in permittivity or index of refraction at optical wavelengths. Unfortunately the surface tension of the water causes the structure to collapse to a small index change if left to dry at standard pressure and any temperature. People involved in making aerogels come up against this problem constantly and must resort to the use of pressure chambers, miscible solvents and other tricks to dry out their gels without shrinkage. We have found empirically that a mixture of water and alcohol with a specific gravity of .86 will remove much of the water without collapsing the structure by replacing some of it with alcohol. When the specific gravity is adjusted to about .84 then the structure begins to shrink and the gelatin begins to become more rigid. When we get to .76 to .78 the whole structure is rigid and the manner in which this is done determines the final index modulation of the film and some other properties. Normally the film is soaked with agitation in the .86 bath for a minute or more and then plunged into a much drier bath followed by an even drier and perhaps hotter bath from which it is slowly drawn as a finished piece. Alternatively several more baths may be used to gradually get to the driest possible bath and temperatures should be in the 50 to 70 degree C range for highly modulated broadband films or at room temp or lower for uniformly small modulations. The higher temperatures enable more rapid diffusion of the alcohol into the gel where it can more rapidly dilute, displace and expel the water leaving substantially higher differences between light and dark fringes. ==Heat, Cold and Moisture== Nothing short of laminating the film between two pieces of glass, with a 3 to 6 mm border of gelatin removed from the substrate, will prevent the gel from eventually absorbing enough moisture, when stored at high humidity or near dew point conditions, to cause a total collapse of the holographic fringe pattern. All permanent DCG holograms made since the late sixties have faded to oblivion unless they were stored continually below 90% RH or have been capped with glass. A few thick and dense plastics have also been successful but most coatings and plastic laminates merely act like sponges and then like osmotic pumps carrying water molecules through their surfaces and into the gelatin, which readily accepts it. We always bake our gratings and hoes prior to capping with warm glass, to further insure that the water content trapped in the lamination is small enough to never become a threat to the fragile fringe structure. Trapped moisture that does no harm at room temperature will upon heating become active enough to wet and soften the delicate expanded structure that makes up the diffracting fringes, which will then collapse and join together in a more homogeneous layer, exhibiting only very weak diffraction. The baking is absolutely necessary for stability in extreme environments. We have tested many holographic scanners and outdoor hoes to destruction by baking after capping until the glue holding the parts together decomposes and turns dark. The gelatin and the recorded fringes usually survive up to 230 deg C where they begin to darken and carbonize. Some of this darkening can be attributed to the release of chromium from bonds in the gelatin and its subsequent reduction, along with some chrome salts that were never completely rinsed out during processing. Longer soak times in ever cleaner water baths will remove most of the residual chrome compounds and greatly reduce yellowing by heat and also by UV radiation. The gel does not seem to be affected by low temperatures and the adhesion to glass is good throughout all temperature ranges, provided that the glass was clean and final washed just prior to coating. ==Radiation effects== The effect of high energy radiation on gelatin is also important to anyone intending to put DCG hoes into space or into solar collectors outdoors or into creative lighting designs in buildings where the windows are DCG gratings. Gelatin, like all organic and many inorganic substances will be damaged by photons of more than 4 or 5 electron volts. Eventually all the bonds will be broken if the flux and energy are high enough for long enough. The gel will then be decomposed into loose atoms and molecules incapable of maintaining the original physical form. Fortunately the process takes a very long time to complete, if the gel is protected between two pieces of glass. We have tested holographic scanners sandwiched between two pieces of 1.5 mm thick glass by placing them near a 250 watt low pressure mercury arc lamp for over 24 hours or until the glass itself solarized and became dark near the exposed surface. The gelatin was unchanged in diffractive properties but the glue line and the gel were slightly yellowed which would reduce transmission in the blue region. Less severe tests on display holograms were carried out from 1977 to 1979 where the test pieces were placed out in the open to take on whatever the weather in Salt Lake city and also in New Jersey could dish out. In all cases, for a year or for a month, the glue that we were using then became noticeably yellow but the gelatin and glass remained unchanged within the limits of our ability to measure it optically. Another test was carried out on DCG and three other recording materials that were all prepared in our Paradise lab in 1989 for Northrop electronics division. Several Sample gratings were recorded on thick fused silica substrates and then baked and capped with another silica plate. This time the wave-fronts were measured and photographed before and after the radiation treatments. Neither the efficiency or any other property of the hologram changed from high energy radiation equivalent to several years of direct exposure in space. Somewhere a formal report exists to back up this statement but it did not yield to my searches and the individuals that carried out the work are no longer at Northrop. They did send me some photographs of the wave-fronts and I have those but they cannot tell me what the radiation doses were. In this case the silica could not absorb much of the radiation so it was a truer test of the durability of the gelatin itself. A few of our customers have put our large gratings into green houses as panes of glass and they appear to have survived at least since 1986 or so. Several 16 inch diameter hoes have gone to NASA Goddard where they are used in outdoor LIDAR since about 1991. One early reflection hoe which was not baked out has drifted a little to the blue, nothing that was baked thoroughly before sealing has changed. ==Summary== Our experience with holograms and hoes recorded in DCG since 1974 has been varied and more or less all encompassing with respect to the variety of product and applications possible with this material. We can speak with some authority to the issue of stability and durability in hostile environments. We have made thousands of hoes that have endured 10 or more years of industrial or commercial environments without failing, as long as they were sealed between two pieces of glass at least one half mm thick with at least 3 mm of cleared area near the outer rim of the sandwich. We have also had a lot of failed product that was sent out without that total protection. The O ring type seal formed by the glass to glue to glass bond in the cleared region is absolutely a must for longevity as is the final bake-out before capping. To neglect the O ring will most likely result in a faded recording over time, if ample water vapor is also present. At a minimum the edges of the recording will disappear for several mm into the sandwich. Capillarity pulls the water ever farther into the plates until most or all of the gelatin softens and collapses. Radiation does not seem to be any more hazardous to gelatin than it is to glass and it holds up better than any plastic we have embossed into. Most of the horror stories of disappearing hoes or blue shifting hoes or the loss of some initial efficiency have their origin in less than optimum preparation before capping. We think we know how to do it right and now so do you. ''RDR'' ''Last modified on 2/18/99'' ae87da5794d192bb1f71e9c50c91703ec54ed208 0 515 1825 1181 2013-05-12T04:08:23Z Jsfisher 1 1 revision wikitext text/x-wiki Stephen Benton [[Image:Benton.jpg]] In Memory: (December 1, 1941 - November 9, 2003) Allen Professor of Media Arts and Sciences Director, Center for Advanced Visual Studies Group: Spatial Imaging [http://www.media.mit.edu/~sab Benton at MIT]] Biography Stephen Benton was best known as the inventor of the white-light "rainbow" hologram, most often seen on credit cards and magazine covers. He was also known for the work he and his group did to create the world's first real-time interactive holographic video system. He was a prolific author and held multiple patents in optical physics, photography, and holography. Benton headed the Lab's Spatial Imaging research group. While an MIT undergraduate, Benton worked with Harold "Doc" Edgerton in the famous "Strobe Lab," and received his BS degree in electrical engineering in 1963. He continued his studies at Harvard University, receiving a PhD in applied physics in 1968, and remained at Harvard until 1973 as its first assistant professor of applied optics. He was associated with laboratories of the late Edwin Land at Polaroid Corporation since his undergraduate days, and returned there to establish an imaging physics laboratory, where he did much of the early work on white-light viewable holograms, and explored other applications of lasers to photography. Curriculum Vita 1999 E. Rudge ('48) and Nancy Allen Professor of Media Arts & Sciences Head, Spatial Imaging Group, Media Laboratory Director, Center for Advanced Visual Studies (CAVS) Graduate Officer, Program in Media Arts & Sciences Massachusetts Institute of Technology 1999 Vice President, Society for Imaging Science & Technology 1996 Director, Center for Advanced Visual Studies (CAVS) 1990 - 1993 Board of Governors, Int'l Soc. Optical Eng'g (SPIE) 1987 - 1994 Founding Head, MIT Program in Media Arts & Sciences 1987 - 1992 Board of Trustees, Museum of Holography, New York 1984 Founding Faculty, Media Laboratory, MIT 1982 Founder, Spatial Imaging Group, MIT 1980 - 1984 Chairman, US National Committee for the International Commission for Optics 1980 - 1983 Visiting Scientist, MIT Laser Research Center 1979 - 1984 Visiting Committee, International Museum of Photography at George Eastman House 1978 - 1981 Board of Directors, Optical Society of America 1976 - 1977 President, Optical Society of America, New England Section 1973 - 1982 Senior Scientist, Polaroid Corporation 1968 - 1973 Assistant Professor of Applied Optics, Harvard University PUBLICATIONS: Articles: 46 Patents: 14 EDUCATION: Bachelor of Science in Electrical Engineering, MIT, 1963 Master of Science in Engineering, Harvard University, 1964 Doctor of Philosophy in Applied Physics, Harvard University, 1968 PROFESSIONAL SOCIETIES Optical Society of America (Fellow, former Director) Society for Imaging Science & Technology (IS&T/SPSE) (Fellow, Vice President) Institute of Electrical & Electronic Engineers The International Society for Optical Engineering (SPIE) (Fellow, former Director) Society for Information Display (SID) Holographic Display Engineers & Artists Club (HODIC, Japan) 42cb8fb62edab870ef208aab91ebf66a925f988a 0 517 1827 1185 2013-05-12T04:08:23Z Jsfisher 1 1 revision wikitext text/x-wiki Staight edges, as pointed out, are to lay out straight lines and to check if things are straight and flat. Wooden materials are bad to use as staight edges as they usually have bows in them. Squares and metal rulers are good straight edges. Plastic rules are also good straight edges. A drywall square has a 4 foot straight edge with measured increments. For very long straight lines, a chalked string line (called a snap line) can be used. In expensive large straight edges can be purchased as "flat ground steel" from industrial suppliers like MSC Industrial or McMaster-Carr. Be very careful with your straight edges as they can get easily get nicks that will effect their ability to measure flatness. ==Testing a Straight Edge== If you compare any three straight edges thay can only be straight if they all match. Any two straight edges can match if they have the same curve. But, for three to match they must all be straight. 908b84de14ec2f9f306718050160d52b47145ee9 0 851 1829 1828 2013-05-12T04:08:23Z Jsfisher 1 1 revision wikitext text/x-wiki == CW Developers == CW developers are allegedly suitable for exposures with continuous wave lasers (as opposed to pulsed lasers). The CW-C2 developer is named for its inventors Cooke and Ward, not its use with CW lasers. It debuted in the March, 1984 issue of ''Applied Optics'' in an article authored by D. J. Cooke and A. A. Ward. Note that the JD-2 and JD-3 chemistry use the same exact developer, and that it is closely related to the CW-C2 developer, using 25% less urea, but otherwise the same. {| border="1" ! !'''''CW-C2''''' !'''''JD-2/3''''' !'''''Pyrochrome''''' !'''''Pyrochrome plus''''' |- | align="center" | '''Part A:''' || || || || |- |Metol || align="center" | || align="center" | || align="center" | || align="center" | |- |Pyrogallol || align="center" | || align="center" | || align="center" | 10 g || align="center" | 20 g |- |Catechol || align="center" |20 g || align="center" |20 g || align="center" | || align="center" | |- |Ascorbic acid || align="center" |10 g || align="center" |10 g || align="center" | || align="center" | |- |Sodium sulfite || align="center" |10 g || align="center" |10 g || align="center" | || align="center" | |- |Potassium metabisulfite || align="center" | || align="center" | || align="center" | || align="center" | 30 g |- |Urea || align="center" |100 g|| align="center" | 75 g || align="center" | || align="center" | |- |Water || align="center" | 1000 ml || align="center" | 1000 ml || align="center" | 1000 ml || align="center" | 1000 ml |- | align="center" | '''Part B:''' || || || || |- |Sodium carbonate || align="center" | 60 g || align="center" | 60 g || align="center" | 60 g || align="center" | 130 g |- |Water || align="center" | 1000 ml || align="center" | 1000 ml || align="center" | 1000 ml || align="center" | 1000 ml |- | align="center" | '''Working solution:''' || || || || |- |Mix A + B + water || align="center" | 1 + 1 + 0 || align="center" | 1 + 1 + 0 || align="center" | 1 + 1 + 0 || align="center" | 1 + 1 + 0 |- |Development time || align="center" | 2 min a 20 C || align="center" | 2 min at 20 C || align="center" | 2 min at 20 C || align="center" | 2 min at 20C |- |Hologram type || align="center" | Reflection || align="center" | Reflection || align="center" | Reflection || align="center" | Reflection |} bdedb3ee9bbdbf8f27a04f3b158be61b8c4ed95e 0 520 1831 1191 2013-05-12T04:08:24Z Jsfisher 1 1 revision wikitext text/x-wiki ==TJ1 Developer== by Jeff Blyth '''Part A''' *6g Metol (4-methylaminophenol sulfate) *1 litre deionized water Dissolve up first then add:- 40g. Ascorbic acid (vitamin "C") '''Part B''' *100g sodium carbonate anhydrous *30g sodium hydroxide *1 litre deionized water. (This one should be labeled "very caustic" use rubber gloves and eye protection --guard against splashing at all.) Just use equal volumes of A and B with the "floating dish" method. (2 close-fitting plastic dishes are arranged so that one floats ontop of the other which contains the developer. The volume in the lower dish should be just enough to give a minimal air gap so that the uptake of oxygen is minimised and the top dish can be used as a rocker to agitate developer over a plate. Development time:- This developer is intended to react fast (to keep the silver grains spheroidal rather than filamentary, and to minimize damage to the gelatin in the strongly alkaline solution). So sufficient exposure level to give a development time of only 15-30 seconds should be aimed for . ==Notes== Developer's lifetime with the floating dish method can be days, depending on usage. A yellow or mild brown color means the developer is still good. When the developer is very dark brown or black it should be discarded. ==How this developer is thought to operate== ''The ascorbate ion with lots of alkalinity around (Na hydroxide /carbonate) is a powerful reducing agent that gets oxidized by light-damaged AgBr grains to "dehydro-ascorbate " and black or brown Ag metal grains are produced.But ascorbate ions with their negative charge are slowed from approaching the Ag+ ions in the lattice of the grain because each Ag+ is surrounded by a barrier of about 6 oppositely charged Br- ions. in the latticework, which is most often in the cubic form. (AgBr crystals can be structurally like the familiar cubic NaCl crystal , each Na+ being surrounded by 6 Cl- ions and each Cl- ion is surrounded by 6 Na+ ions ).The negative Br- ions in the lattice repel the easy access of the negative ascorbate- ions.. However “metol” is a reducing agent which is a sulfate salt and is therefore positively charged. These positive reducing ions can pass rapidly through the negative Br- lattice barricade and start reducing the Ag+ to uncharged silver metal and causing the Br- lattice ions to go into solution. But the ascorbate ions are slightly more powerful reducing agents than the metol ions so that causes newly oxidized metol ions to get returned to their original reduced form by the ascorbate ions. Therefore the metol acts as a catalyst for the ascorbate developer because it may be only momentarily oxidized.. Only when much of the ascorbate has got oxidized, do the metol ions really start to stay oxidized and oxidised metol is nearly black whereas oxidized ascorbate is merely yellow-brown. This has the useful bonus of causing the developer to get increasingly dark and this therefore acts as an indicator that it is becoming exhausted . When the developer is virtually black and opaque it means that most of the ascorbate has been oxidized and the solution should be discarded. ( Slight darkenening means the developer is OK still) . --- Another bonus about metol seems to be that it has an instant slight hardening action on soft gelatin as can be found from doing a fingernail scratch test on the notoriously soft Slavich PFG-03 emulsion after say 15 seconds immersion in “TJ1” developer made up with and without metol.'' 2cdb9145542c1d92f189d81ee9ab3881859f08aa 0 522 1833 1195 2013-05-12T04:08:24Z Jsfisher 1 1 revision wikitext text/x-wiki ==Setting up a table saw== *Set the blade to full depth. *Measure the blade to table angle with a square. *Adjust the blade angle to square. *Set the blade depth. If making a through cut you want the blade to not be higher than 1 tooth above the work. *Adjust the fence to position. Very carefully measure from the edge of a front tooth to the fence and then measure the tooth on the back edge the blade the fence. Adjust the fence until they are equal and the fence is square. *Setup the miter carage ==Choosing the proper blade== ==Cutting Aluminum== ==Cross cutting== ===Cross Cutting with a Fence=== ==Safety== 735609e86c695544ae6fcbb42d5febc20e22eab8 0 570 1835 1291 2013-05-12T04:08:24Z Jsfisher 1 1 revision wikitext text/x-wiki ===Dust Hoods=== Keeping your work area dust free is a prime consideration when making your own emulsions. HEPA work stations are commercially available but are expensive. A home made work station can be easily made. [[Image:LaminarDetail.jpg]] John Peccora built this nice bench top Dust hood for DCG plate coating. On the left is the front view and on the right is a side cross section. For the back wall he used a plastic material that looks like square tubes with a screen covering. [[Image:CommercialLaminar.jpg]] This is a Commercial HEPA work station made by [http://www.nuaire.com/ NuAire]. It has pre-filters on the bottom with a squirel cage blower and the entire back of the work area is one large HEPA filter (4' x 3'). There are four 4' flourescent bulbs in the top. In order to make sure there are no air vortexes that can trap dust it is important to have the air flow over the entire bench in a laminar fasion. In order to insure a laminar flow the air needs to be directed through a parallel series of tubes. A bunch of straws work perfectly. In order to test the flow one can take a candle and put the flame in different places in the work area. Places where the flame flickers have turbulence and are unacceptable. ===Fume Extraction=== Processing with formaldehyde and alcohols are common in processing holograms. The fumes are dangerous and provisions should be made for venting them saftly outside. A simple bathroom fan is insufficient. Commercial suppliers like [http://www.mcmaster.com McMaster Carr] and [http://www.mscindustrial.com MSC Industrial] have explosion proof fan assemblies in the $500 range. A good rule of thumb is to have enough venting to exchange the complete air in your room 30 times per hour. Check your local regulations for more requirements. ===Processing Areas=== The processing are needs to be designed with a few considerations: *Light tight *Washable surfaces *Dust free *Running water *Lockable chemical storage *Counter space for processing trays ===Safe lights=== In order to see while you are working it is important to have some light. Fortunately if you are using film that is only sensitive to red you can make a green safelight. You should test your safelight before you use it. If you are using long settle times it is wise to make sure no safelight hits the bench during the settle period. ====Testing Safe Lights==== Do a preliminary test of reflecting the light off of a diffraction grating, CD or DVD. Shine the safe light at the grating and bounce the reflection back to your eyes. If it looks the same then you are looking at the zero order reflection, rotate the grating or CD until you see a reflection that looks like a rainbow. This is a higher order reflection. If you can see red in this reflection then your light is not safe. ====Exposure Test==== The next test is to get out a piece of your film. Find the uncoated side. Place a piece of electrical tape down one side to make a test patch that has not been exposed. Put the film about a foot from your safelight with the tape facing the light. Add one piece of tape at 15 seconds, 30 seconds, 60 seconds, 10 minutes, 30 minutes. At 60 minutes put the plate in developer. If your plate turns completely black then your safelight is not usable. If only the 60 minute or 30 minute lines develop you are probably OK. ====Safe Light Types==== '''For Red Sensitive Film''' *Lime Light: The easiest light to use is a "Limelight" night light. It is very low power and mostly green. If you add a Rosco Gel #90 available from a theatrical supply shop it will be very good but very low power. Attach the gel with electrical tape. John Klayer uses a row of gelled Limelights above his bench. *Kodak Safe Lights: Kodak makes a #7B and #3 green saflelight filters (#3 is recommended by Shoebox Holography) suitable for red sensitive holographic films. *Home Made Lights: Just using a piece of Rosco #90 (Theater Gel) over a conventional bulb is not enough. Use two layers of #90 or better to have one layer of #90 and one layer of #95. #95 lets in too much deep red to use alone and #90 lets in too much yellow that the Slavich materials are sensitive to. *MiniMag Flash Light: Use Two layers of Rosco #90 or better yet one layer of #90 and one of #95 for red sensitive film. *T40 EncapSulite fluorescent bulb covers can be used for holographic safelights. [http://www.flexopress.com/production/encapsulitelightsleeves.html EncapSulite] For general information about Safelights see: [http://www.kodak.com/global/en/consumer/products/techInfo/k4/k4Facts.shtml Kodak Safe Lights] 1e39ee67f2f384f525685676d7e63b86a502a8b7 0 571 1837 1293 2013-05-12T04:08:24Z Jsfisher 1 1 revision wikitext text/x-wiki ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and Dichromated Gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300nm long and 1.5nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape(2,3,4,5,19). If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties(6,7). These two images were taken from source (16). [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion(6,8,9). Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions(13,14). Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom(13,14). This image was taken from source (16). [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them(10,12). Research is needed using vitamin C with CrVI(11). ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII (15). During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram(15). The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://en.wikipedia.org/wiki/Collagen # http://www.britannica.com/eb/article-72553/protein # http://www.lsbu.ac.uk/water/hygel.html # http://www.stanford.edu/~spark7/ # http://en.wikipedia.org/wiki/Gelatin # http://www.lsbu.ac.uk/water/hygel.html # http://albumen.stanford.edu/library/c20/kozlov1983.html # http://www.greatlakesgelatin.com/gelatin%20information.htm # http://www.cdc.gov/niosh/topics/hexchrom/ # http://en.wikipedia.org/wiki/Hexavalent_chromium # http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/ # http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf # http://www.gelatin-gmia.com/index.htm # Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora # http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html # http://sandwalk.blogspot.com/2007/02/collagen.html d8a58ace23ab9b4c17938f8195ba69b3c28a8a22 0 852 1839 1838 2013-05-12T04:08:24Z Jsfisher 1 1 revision wikitext text/x-wiki Optical design programs are really fun to use and Time Reverse Ray Tracing is just about the most fun anyone could have with a computer. The object is to model an ideal HOE that works at a wavelength not possible to record at and then go back in time to see how it could have been made, but with a convenient wavelength. Some would call this reverse engineering but that would be a misnomer because the finished product only exists as a math model in your computer. Others would call it designing a null optic, because the object is to feed your ideal optic a completely wrong input wave and null out all the aberrations in the output wave. The null is a little closer except that some solutions require 5 or 6 elements in one leg and a few more in the other leg, and that would be an insanely complex null optic. A few others could probably work out an analytic solution that was close and maybe not even trace it. I typically model the HOE surface, launch a smooth reference wave of 488 nm light through it, look carefully at the mess the HOE makes out of it and then methodically insert real components in the path until the rays converge to a small common point. Obviously, that is the object point where the laser light must have come from to make the HOE that was originally modeled, thus Time Reverse Ray Tracing. The first correction is usually for astigmatism because the original HOE is probably used off axis and a simple off the shelf cylindrical lens will get most of it. Sometimes taking liberties with the Brag condition by moving reference points around will also help reduce the astigmatism and the other aberrations, this can easily be overdone. The next step may be to insert a bent spherical lens and optimize allowing decenters and maybe some limited tilt and maybe some sliding of the cylinder lens. After that the game gets rough quickly, a few more spherical surfaces will gain a little more ground but improvement gets harder and harder to find. The overall object is to get a good focus so that a simple spatial filter can be used to illuminate the optical train you will be building. My design experiences have been very rewarding sometimes and really awful at least once. My worst nightmare was a 1064 nm design that required a bilaterally symmetric binary optic to reduce the aberrations to about 1 wave. The design required help from another designer and the construction took the better part of 6 months just to align all the optics. The computer provided close positioning of the components but the final tweaks required an entire cycle of construction, optical test, computer modeling of the possible error, repositioning of suspected components and construction again. The cycle time was one or two days because the dichromated gelatin optic was 400 mm in diameter. Figure 1 is a scaled phase map of the binary optic we had to fabricate before a carrier was added to move the orders off axis. A metal binary mask was contact copied into several phase media to make it efficient enough to be usable. [[File:timerev2.jpg|center]] <strong><u>Figure 1.</u></strong> Another recent design turned out to be a dream come true. It took about 1 day to complete, requiring only one cylindrical lens, one plano convex lens and a small adjustment of the construction points. Figure 2 shows the 488 nm construction layout for forming a well corrected off axis 100 mm diameter f# 2.3 lens to be used at 532 nm. The reference wave was nearly collimated and the object wave came from a pinhole and passed through only two real off the shelf lenses. It was straight forward to align the optics and easy to verify that the design worked. The fringe tilt error introduced during master construction was corrected in a simple contact copy made at a compensating angle. Rays were traced to just 1 wave of error and measured spots at 532 nm were about 50 microns, about the limit for the glass used. All the design work was done in ZEMAX-EE but could have been done as well in SE. [[File:timerev1.gif|center]] <strong><u>Figure 2.</u></strong> Time Reverse Tracing is limited at present by the inability to insert optics into the construction path of standard HOE surfaces in any current optical design program. When that becomes possible, many more ideal HOEs may be modeled and reverse traced at convenient wavelengths. A General Holographic Surface has been proposed for inclusion in a future version of ZEMAX and KDP optics. No telling when it will become worthwhile. ===Primary References:=== * "Wavelength Compensation by Time Reverse Ray Tracing" SPIE vol 2404, p. 217 Diffractive and Holographic Optics and Technology II, San Jose CA, Feb 1995. * [[Wavelength compensation at 1.064µ using hybrid optics|Wavelength compensation at 1.064 microns using hybrid optics]], SPIE vol 2689, Diffractive and Holographic Optics Technology III, San Jose CA, Feb 1996. ===Other References:=== * ''Wavelength Scaling Holographic Elements.'' M. Malin and H.E. Morrow. Opt Eng 20:756- 8 S/O '81 also in SPIE vol 240 p 2, 1980, San Diego * ''Analytic Design of Optimum Holographic Optical Elements.'' J.N. Cederquist and J.R. Fienup. bibl diags J Opt Soc Am A 4:699-705 Ap '87 * ''Analytic Optimization for Holographic Optical Elements.'' E. Hasman and A.A. Friesem. bibl diag J. Opt Soc Am A 6:62-72 Ja '89 * ''Design of Holographic Optical Elements by Using Recursive Techniques.'' Y. Amitai and A.A. Friesem. bibl il diags J. Opt Soc Am A 5:702-12 My '88 * ''Computer-Based Analysis of Hologram Imagery and Aberrations.'' J.N. Latta. bibliog diags Ap Optics 10:599-618 Mr '71 * ''Holographic Elements with High Efficiency and Low Aberrations for Helmet Displays.'' Y. Amitai and others. bibl il diags Appl Opt 28:3405-16 Ag 15 '89 * ''Holographic Zone Plates for f'0 and Collimating Lenses.'' Y. Ono and N. Nishida. diags Appl Opt 25:794-7 Mr. 1 '86 * ''Iterative Method Applied to Image Reconstruction and to Computer-Generated Holograms.'' J.R. Fienup. bibl il diags Opt Eng 19:297-305 My '80 * ''Design Techniques for Forming 488-nm Holographic lenses with Reconstruction at 633 nm.'' M.R. Latta and R.V. Pole. bibl il diags App Opt 18:2418-21 Jl 15'79 * ''Compensation of Wavelength-Shift Aberrations in an off-axis Holographic Zone Plate.'' E. Wihardjo and others. bibl il diags Opt Eng 25:871-4 Jl '86 * ''Cindrich, ed. Holographic Optics: Design &amp; Applications.'' 1988. 50.00 (ISBN 0-89252- 918-0, 833). SPIE * ''Computer Originated Aspheric Holographic Optical Elements.'' R.C. Fairchild and J.R. Fienup. bibl il diags Opt Eng 21:133-40 Ja/F '82 * ''Recursive design of a holographic focusing grating coupler.'' Y. Amatai, I. A. Erteza, J. W. Goodman. Ap Opt vol 30, no 27, p 3886 Sep 91 * ''Using a Conventional Optical Design Program to Design Holographic Optical Elements.'' C.W. Chen. bibl diags Opt Eng 19:649-53 S/O '80 * ''Describing Holographic Optical Elements as Lenses.'' W.C. Sweatt. bibl diags Opt Soc Am J. 67:803-8 Je'77 * ''Compensation of Aberrations Due to a Wavelength Shift in Holography.'' J.M. Moran. il diags App Optics 10:1909-13 Ag '71 * ''Computer-Based Analysis of Holography Using Ray Tracing J.N.'' Latta. bibliog diags App Optics 10:2698-710 D '71 ''Last modified on 1/11/98'' [[Category:Rallison]] 568661a98b1c9e7c2b96e061be6ce7503924e29f 0 573 1841 1297 2013-05-12T04:08:24Z Jsfisher 1 1 revision wikitext text/x-wiki ===''Pinhole Calculation''=== As per Newport. D = Fw/a , where D = Pinhole Diameter F = Objective lens focal length w = Wavelength of laser (sorry no greek letter on my keyboard) a = Beam radius at input to lens More.... [http://www.newport.com/store/product.aspx?id=3873&Section=detail&lang=1# "Newport Pinhole"] ===''Calculating Laser Power vs Film Requirement vs Exposure Time w/Sample''=== Joules = Watts x seconds thus 1 mW = 1mJ/1 second 1 inch = 2.54cm 1 square inch = 6.45cm^2 For a film requiring '''100 mJ per cm^2''' Plate length(2.54 cm) x width(2.54 cm) = '''6.45 cm^2''' Laser putting out 10mw = '''10mJ per second''' '''10mJ per second''' /'''6.45cm^2''' = 1.55mJ per cm^2 per second '''100mJ per cm^2'''/1.55mJ per cm^2 per second = 64.5 seconds This is just a basic starting point based on the film energy requirement. Adjustments need to be made for laser light losses, processing etc.... ===''Detecting the Emulsion Side of the Plate''=== Most of these can be tried with a used piece of film plate with the lights on for practice. Note: These tricks rely on the fact that only one side is gelatin; with the Fuji film both sides are gelatin. If you breathe on the plate, the side that does not fog will be the emulsion side (no condensation occurs on the emulsion side because the gelatin absorbs the moisture). (This does not work for the Fuji film as it has gelatin on both sides.) Look at the edge of the glass with a safelight - the cleanest (non-ragged) edge is the emulsion side. With a bit of practice you can detect the difference in the dark by rubbing your thumbnail along the edge. If all the plates are oriented the same way, you can label the box ''emulsion this side ->'' The two finger method: moisten your thumb and index finger and pinch them together a few times. Now do the same motion with the plate between them, and it should be easy to feel which side is the sticky emulsion side. ===''Got old plates?''=== I have stacks of failed plates. Do yourself a favor now that you have some scrap plates: Spray paint one of the ruined jobbies white and use that as a dummy plate when setting up. Both sides and the edges. You will find this very useful when it comes to carding off light that would otherwise enter the edges of the glass as well as for checking the quality of your reference beam. A clean white surface is also nice for making sure that you have no specular reflections from shiny places on your object(s)... 9c1bd633db1f6db02b455471735d8373e0d05614 0 576 1843 1303 2013-05-12T04:08:25Z Jsfisher 1 1 revision wikitext text/x-wiki '''Correcting Milky Holograms''' Milkiness is caused by the film being too soft. There are many ways of fixing this problem (making the emulsion harder) but increasing exposure is not the best way. It sounds as if the gelatin you are using is naturally soft. So let's look at some other ways to use your gelatin and get it harder. You could try any of these or combination of these with a shorter exposure time. 1. First, shorten your exposure let's say by half (10min). Then after the exposure hold the hologram in your hand by the edges and with the laser shutter open, hold the hologram in the laser light and keep moving it side to side. The idea is to get additional crosslinking and thus hardening without actually creating any more fringes. Do this for the remainder of time of your original exposure so do this for the 10 minutes you took off the original time. If you cut your exposure to 5 minutes then do this for 15 minutes. After some testing you may be able to cut this additional lighting time down. 2. After a shorter exposure, 5 or 10 minutes, and before processing put the hologram in a lab oven (do not contaminate your cooking oven) and bake it at about 120F (49C) for 3 to 5 minutes. It's best to have a piece of flat steel in the oven to lay the hologram on, so when you put the hologram in the oven, it heats up all at once. Then when you take the hologram out of the oven, place it on anther piece of flat steel to cool it evenly. 3. Prior to exposure do the above baking technique. Then let the hologram cool and stablize to ambient room temperature and humidy before shooting. 4. Decrease the amount of water in your homemade "Fixer" (pyrosulphate/alum/water 20g/4g/400ml) and increase your fixing time. You'll have to test the increased fixing time as you never stated how long you fix. With higher concentrated formula, you may not have to increase fixing time at all but a little testing will tell. If you get too long, greater then 2-3 minutes, then decrease water. It's best to keep fixing to about 1 - 2 minutes. Try 20g/4g/300ml. 5. Put a couple of drops of Glycerol (glycerine) in your original emulsion formula. This will help speed up dark reaction in those 24 hours which will essentially cause the film to be a little harder. 6. Age your plate in a very dry area for 2 maybe 3 days instead of 1 day. You could make a few plates and shorter expose a plate each day and see what happens as the plate ages. 68cecf17abb4f5d752095f0e5e6b52ab900f9a5c 0 577 1845 1305 2013-05-12T04:08:25Z Jsfisher 1 1 revision wikitext text/x-wiki ===Troubleshooting=== So you made a hologram! But it is either not perfect or not even visible. Don't despair. We all have made holograms that are blank or have issues. I am going to run down the list of mistakes I have uncovered. For tips on troubleshooting DCG specific problems see [[Troubleshooting DCG]]. For some tips on variables see [[DCG Variables]]. ====Image Missing==== Motion or improper developing. Card left in the object beam or reference beam after checking beam ratios. ====Image Missing parts==== If the object is missing parts then the object was in motion during exposure. If the film is missing views then that portion of the film was in motion. Air bubbles in the index matching fluid will cause this problem. ====Image "Drippy"==== This is caused by soft emulsions and/or excessive pressure during squeegeeing. ====Image Dim==== Under or over exposure. Motion of the bench or film. Beam ratios wrong. ====Image has Rainbow Lines==== Light entered the edge of the plate and bounced between the two surfaces. Make sure to block any light entering the edges of the plate during exposure and reconstruction. ====Image has Circular Patterns (Bull's eye)==== Dust under film when laminated to the backing plate before exposure. ====Reflection Hologram Blurry==== It is normal to only have 4 inches of usable depth. The actual depth is related to how narrow of a bandwidth you are using for reconstuction. If you are looking for greater depth adjust your development to narrow the reconstruction bandwidth. There will be a corresponding decrease in brightness. In an H2 set-up it can be the object beam was too bright. As measured at the film plane the object can not be brighter than the reference beam. ====Image has Black Lines on the Object==== Object moved slightly. [[Image:ObjectMove1.jpg]] As you can see the piece of paper under the kitty moved causing the large black lines. ====Entire Image has black lines on it==== Laser changed frequencies during exposure (mode hop) or is running in two lines. ====Image Flashes at Extreme Viewing Angles==== Laser beam was reflecting off something on the table and reaching the plate. It is important to card off any stray light from the beam. ====Image has Black Lines on the Plate.==== The plate was moving during exposure. ====Plate is Completely Dark==== Overexposed. Fogged film. ====Plate won't Turn Dark in the Developer.==== Underexposed. Old chemistry. Forgot to add part B for 2-part developer. ====Image Flashes Rainbows from a Specific Location==== This spot is too bright/overexposed. If the object is very shiny try spraying with a flatting spray. Flat clear lacquer works if you can't find flatting spray. Rotating the polarization of the object beam with a 1/2 waveplate can turn off shiny parts of the object. Use a polarizer rotated to coincide with the reference polarization to view the object illumination as you rotate the 1/2 waveplate. ====The image has black spots on the Emulsion==== This is called burnout and is most common in image planed H2 copies. It can be corrected by: # Composition, and pre-visualization of the location of the recording plane of the transfer (H2) within it, # Cighting of the scene when making the master (H1) so as to avoid the highlights near the intended transfer plane, # Possibly manipulating the polarization of the scene lighting to reduce the highlights, # Setting the beam ratio by measuring the "object" light in the transfer recording plane at the location of the burn spots (which are easy to find by placing a card in the plate holder) and with a detector about the same size as an average burn spot, # Using a beam ratio and exposure time that gives optimum performance at the location of the burns, and # Using a processing regime that doesn't shrink or swell the emulsion as a function of beam ratio or exposure intensity. ===Diagnosing the Problem=== Once you have identified the cause it is important to figure out exactly what corrective action will help. Motion This is one of the most common problems. To find out if you are stable it is useful to make an [[Interferometry#The_Michelson_Interferometer|Interferometer]]. ===Pictures of Defects=== [[Image:Drippy.jpg]] Here is a hologram that is "drippy" or has "rainbow lines". It was caused by laser light entering the edge of the plate during exposure. Either design your plateholder to block light entering the edges of the plate or tape the edge off with electrical tape. [[Image:Woodgrain.jpg]] This hologram shows "woodgrain". It is caused by the laser light reflecting back and forth from the front to the back of the plate. Make sure you have the corect polarization of the reference beam and make sure the reference angle is somewhere near 54 degrees (Brewsters Angle). [[Image:ObjectMovement2.jpg]] This hologram shows the difficulty of making a hologram of paper. Here the paper moved, either because it was not trapped tightly enough or because it was changing humidity durring exposure. [[Image:PlateMovement.jpg]] Here is a hologram showing plate movement. The dim spots do not change based on view point. [[Image:UnderExposed.jpg]] This hologram was underexposed. You can tell it is under exposed because it is dim and it is even dimmer at the edges where there was less light. If the edges were brighter then you would suspect over exposure. [[Image:BurnOut.jpg]] This hologram shows "Burn Out". The little finger is very reflective and was placed too close to the film plane. You can see the black smear above the finger tip. 9b362a138549ccd4c405172a4bd252026a1c7dee 0 853 1847 1846 2013-05-12T04:08:28Z Jsfisher 1 1 revision wikitext text/x-wiki {| border=1 |- | colspan="3" | '''Key''' |- | a = input angle in air || b = output angle in air || a_n = input angle in medium |- | b_n = output angle in medium || f₀ = spatial frequency = 1/d || λ = wavelength |- | n = index of refraction || Δn = index modulation || D.E. = diffraction efficiency |- | φ = The half angle || d = grating period || T = thickness of medium |- | ρ = regime factor || Q = quality factor || B = fringe tilt angle |- | 0, +1, -1, +2, -2 = diffraction orders possible || f = focal length || f# = f number |} {| border=1 |- | '''Grating equation, transmission''' |- | f₀λ = sin a + sin b |- | D.E. <u>~</u> sin² [Δn T / (λ cos φ)] < 99.9% |} {| |- | colspan=2 | Plane grating, slanted fringes, +3 order is TIR, Δn is asymmetric |- | [[File:fig1.gif]] | * <math>\Delta \lambda \simeq \frac{\lambda d}{T \tan{\phi}} \simeq \frac{\lambda \pi \Delta n}{8 n} \simeq \lambda \arcsin{\left(\frac{1-Q}{1+Q}\right)}</math> * <math>a_n = \arcsin{\left(\frac{\sin{a}}{n}\right)}</math> * <math>b_n = \arcsin{\left(\frac{\sin{b}}{n}\right)}</math> * <math>B = \frac{b_n - a_n}{2}</math> * <math>\text{Bragg ratio} \beta = \frac{T \lambda}{d^2}</math> * <math>\phi \simeq \arcsin{n \sin{\left(\frac{a_n + b_n}{2}\right)}}</math> * <math>\text{Number of superimposed recordings} \simeq \frac{n T}{\lambda}</math> * <math>\text{Resolving Power} \frac{\lambda}{\Delta \lambda} \simeq \text{number of fringes}</math> |} {| border=1 |- | '''Grating equation, reflection''' |- | <math>\displaystyle f_0 \lambda = n (\cos{a} + \cos{b})</math> |- | <math>D.E. \simeq \tanh^2{\left(\Delta n T / \left(\lambda \cos{\phi}\right)\right)} < 99.9998%</math> |} Uniform tilted reflector, also has weak transmission grating at surface. {| |- | [[File:fig3.gif]] | * <math>\Delta \lambda \simeq \frac{\lambda d}{T}</math> * <math>\Delta \theta \simeq \frac{d}{T}</math> * <math>\displaystyle 0 < \Delta n < 0.27</math> * <math>\displaystyle 3 u < T < 50 u</math> * <math>\rho = Q \frac{\lambda^2}{d^2 n \Delta n} \simeq \frac{2 \pi \lambda T}{d^2 n} \simeq \frac{2 T}{d^2}</math> * <math>\frac{1}{\rho^2} \propto \text{power lost to higher orders}</math> |} ''Last modified on 9/29/97'' [[Category:Rallison]] b92b653db2c77043def83db1ad6f3a2ea957401b 0 588 1849 1327 2013-05-12T04:08:28Z Jsfisher 1 1 revision wikitext text/x-wiki Veil Coating ==Veil Coating - Part I== The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70F.) Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45 degree angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. ===Post Spinning - Part IIa=== Take the plate and immediately place it on a turn table and spin it as 78 RPM’s. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. ===Post Leaning/Lying - Part IIb=== If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. ===Re-Using Emulsion - Part III=== If you run out of emulsion in the pouring container while coating, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. Allow the emulsion to come back up to coating temperature of 110 to 120F. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. Although refilter does not have to be done during one session if things are kept clean, I suggest refiltering after refrigerating and re-cooking. ==Dave Battin's Article on Veil Coating== Having tried all the methods available to most hobby holographers, I've found the best method for me is the veil coat method. I have attached a still shot to give you a preview to this method, and I plan on showing a step by step instructions so all should be able to coat easily. please see the video clip at the bottom of this page to see this method in action, sorry for the weird color ,as im actually making DCG film under a yellow/red safelite [[Image:VeilFig1.jpg]] The size of the glass is 4"x16" if i trim off one inch the top it will yield me Three nice 4x5s. When acquiring glass I have found a great source is at your local art store, the type that has a special every week, (here its called Michael's), Its the replacement glass sold for picture frames, located in or near the framing department. It comes cleaned sealed and slightly lighter/weight than the regular 1/8" glass found at the local hardware store. The largest I can get is 16"x20" for @ $5 each, not bad for coming cleaned and ready to cut .................. subbing will be next [[Image:VeilFig2.jpg]] I have found it much easier to cut the glass into 4”x16” pieces before subbing. [[Image:VeilFig3.jpg]] A simple jig to cut your glass will give you nice consistent cuts every time. By banking your glass to the stop and placing the proper width spacer on top, simply bank your glass cutter against the spacer and slice. It’s best to provide a little lubricant to help the cut a little (I lick the cutter first). Now that my glass is cut, I'll prep the surface for coating. This glass is pretty clean already. If you’re unsure, I would soak it in a 20% Clorox Solution (soak over night), and after a quick water wash, soak in the Cascade (dishwasher soap) and water mix (I use a small handful for 2 gallons of water or so) again soak overnight after a slight scrubbing action using a plastic scrubby pad. [[Image:VeilFig4.jpg]] After removal of the glass from the Cascade, I give it a quick dip into clean water and then a final plunge into what they refer to as (Trisodium Phosphate) substitute. Where I live, they won’t allow the use of the real TSP, as it’s bad for the ground water. Allow to dry by leaning on wall, sitting on a paper towel. [[Image:VeilFig5.jpg]] The glass is now ready to be coated, but we must add a few extra items to make things easier later on ………………………… [[Image:VeilFig6.jpg]] Well, the glass is almost ready to coat. We will have to attach a few pieces of tape and paper to make this work correctly. [[Image:VeilFig7.jpg]] I do all the work under my laminar flow booth. It helps to place your plate (the glass will now be referred to as plate) on some type of pedestal (as shown) or block of wood. (photo A) Start by placing the plate face down on the pedestal and applying plain old ordinary scotch tape to both long sides of plate, adhere tape directly to the back of the plate, allowing only half of the tape to hang off the sides the entire length of the plate (photo B). I call these gutters. These will allow you to coat your plate up to the very edge without any waste. Once the gutters are in place, turn your plate face up, and again place on the pedestal. Now using a short piece of tape slightly longer than the width of your plate, attach it to the top, adhering directly onto the face of the plate, again leaving half the tape to hang off the top (photo C). Now that the top tape is adhered, we will now apply the “Tab”, a small 1x5 inch piece of paper applied from the back of the plate stuck to the tape along the top. This tab will be used numerous times throughout the operation so be sure its adhered well (photo D). Your plate should now look like this: [[Image:VeilFig8.jpg]] The paper tab I attached to the top of the plate, will now act as a handle and I can hold it while doing a final cleaning, I lay the glass across my leg and wipe it clean (front only)using a folded paper towel and simple Windex glass cleaner ,always spray on the towel and not the glass! With my method of coating I felt to lean is to be constant! The angle of incline is not so important, but its to always repeat the same angle, I achieve this by placing the plate in a holding jig, see the video to help explain, the film is now ready for coating . A few minuets after coating , the paper tab will now allow you to attach a large paper clip, and hang your film to dry. By using a lab base and thin rod clamped horizontally, its easy to hang 12 4x5s to dry! The blow dryer I use is old and weak! But it has two settings hi/low heat, at low it is very weak (blowing), and you will see me blowing close to the wet emulsion. Most new blow dryers will be way to powerful for this. To apply the emulsion I use a simple squirt bottle, very easy to regulate flow, with the current bottle, I can coat three 4x16 plate before I have to recharge the bottle. [http://www.holowiki.com/HoloWiki/images/coatmeth.wmv Dave Battin's Coating Video] (dead link) [http://www.youtube.com/watch?v=b0Toqidt0eo Dave Battin's Coating Video on YouTube] ec8dc6d1636cb12b12fd803c206aaa81c19cdd85 0 591 1851 1333 2013-05-12T04:08:28Z Jsfisher 1 1 revision wikitext text/x-wiki Wave plates consist of some birefringent material (like quartz) and modify the [[Polarization]] of a laser beam. Lambda/4 wave plates (also called 1/4 waveplates) turn linearly polarized light into circular polarized light, and as such are not of great use to holographers. Lambda/2 wave plates (also called half-waveplates) rotate the [[Polarization]] of a laser beam by a fixed amount, depending on the orientation of the preferred axis. They thus need to be fixed in a rotation mount. A waveplate is usually only usable at a single frequency, in order to rotate the polarization of a multi-colored laser beam see [[Fresnel Rhomb]]. Lambda/2 wave plates are often used by holographers for the following reasons: *For rotating the polarization of a laser to avoid holograms with superimposed "wood grain" structure. This arises from interference between beams reflected from the front and back sides of a holographic plate. One technique to avoid this is to use [[Index Matching]], but a simpler method is to illuminate the plate by a reference beam at the [[Brewster's Angle]]. When properly polarized, there won't be any reflections and thus, no interference. When the reference beam is tilted horizontally (vertically), then one needs horizontal (vertical) linear polarization of the laser beam. Small lasers like tubular HeNe lasers can simply be rotated to achieve the correct polarization, but this won't work for larger lasers like [[Types_of_Lasers#Argon_Ion_Lasers|argon lasers]], which are usually vertically polarized. For these, a Lambda/2 (half-wave) waveplate can be used to rotate the polarization appropriately. *For rotating the polarization of the reference with respect the polarization of the object beam, to maximize image contrast or to achieve special effects. If you put a polarizer at the film plane aligned to the polarization of the unaltered object beam so you can see the reflections and place a 1/2 wave plate in the object beam you will see the relative brightness of the reflections dim as you rotate the polarization off axis. Rotate the 1/2 wave plate so the reflections and the diffuse light from the object have the "desired" brightness. Also, make sure that any bright spot is not exactly on the film plane when making an H2 or it will burn out. *In conjunction with a [[Holography_Technology#Cube_Beamsplitters|polarizing cube beam splitter]], a pair of Lambda/2 plates is the best method to split a laser beam into two beams with a variable beam ratio. Wave plates are usually quite wavelength dependent and will work well only very close to their design wavelength. Multi-order waveplate are more wavelength sensitive than zero-order wave plates. There exist however broad band wave plates as well. Usually wave plates are expensive and not too often available as surplus - if you see one, get it! For the hobbyist, there are also the following two options: *If she happens to have a few waveplates designed for other wavelengths than the desired one, try to mount them in tandem and play with their relative orientations: there is often a spot where a linear rotation can be achieved. Even using Lambda/4 wave plates can sometimes work in this way. Another reason to catch any conceivable wave plate on ebay! *LCD screens from old electronic pocket games (in particular Nintendo types from the early 80's) sometimes can be used as broad band Lambda/2 wave plates. This needs to be tried case-by-case. The relevant piece is the top glass plate that needs to be taken off. The disadvantage is often poor optical quality (can be remedied by a [[Holography_Technology#Spatial_Filters|spatial filter]]), and interferences from front and back sides that lead to an uneven illumination. Commercial wave plates are usually anti-reflection coated and so avoid this problem. *Stacks of Seran Wrap can also be stacked to the right thickness for a quick and dirty wave plate. *If you take a piece of mica and flake a few flakes off one may be the right thickness to be a multiorder wave plate. This is another quick and dirty method. 336dffb7800a6bbffb331dc684083a8b6848004d 0 854 1853 1852 2013-05-12T04:08:29Z Jsfisher 1 1 revision wikitext text/x-wiki Richard D. Rallison<br> Ralcon Development Lab, Box 142, Paradise UT, 84328<br> ph (435) 245 4623, fax 6672, e/mail rdr@ralcon.com<br> Steven M. Arnold<br> Diffraction International, 11345 Hwy 7, #421, Minneapolis MN, 55305<br> ph (612) 945 9912, fax (612) 945 9912<br> ==ABSTRACT== The wavelength scaling of an f# 2.5 off axis HOE from 488 nm to 1064 nm has been done. We canceled large induced astigmatism, and other higher order aberrations using a combination of 1 curved reflector, 1 cylindrical lens and one Null CGH bonded to the cylindrical lens. The task was made more difficult by a requirement to fill a 404 mm round aperture and make it focus to a 53 micron diameter spot at the 1/e clip level. The design procedure, the construction sequence and the measured results are presented as a work in progress. ==INTRODUCTION== Our primary objective is to design and construct a 45 deg off axis f#2.5 [http://lazer.gsfc.nasa.gov/ Lidar] scanning optic for operation at 1.064µ. The focal length was selected at 1016 mm with the focus centered and normal to a 404 mm diameter glass sandwich, and the input was designated to enter from 45 degrees off axis so that conical scans of the sky could be made. We had previously tried to obtain a 500 micron spot with an f# 4 design at 670 nm and had succeeded nominally using only a tilted 60 mm fl parabolic mirror and two positive cylindrical lenses¹ to correct the astigmatism and some of the coma like aberration. We also made a design that predicted better performance using a large, tilted and decentered medium power positive meniscus lens, a tilted negative cylinder and a 446 mm D by 1994 mm fl telescope mirror. The design looked good enough to try and we converted to 1.064µ, reoptimized and made a prototype. The spot became nominally smaller, about 400µ but not the 250µ that the design predicted, probably because alignment errors were accumulating. We then added two more weak meniscus lenses on axis to reduce spherical and replaced the large tilted medium power meniscus with a smaller but much stronger positive meniscus to further reduce coma. The predicted spot was to be 200µ plus whatever the random phase error in the glass substrate might add. The computer model was not faithfully translated to actual optics and we had considerable residual astigmatism and other aberrations left over. We measured narrow areas in the lines down to 200 microns and decided the set up had to be simpler and the design had to reduce the aberrations to a few waves, not the hundred or more waves we had been getting. ==DESIGN CHANGES== ===Conventional spherical optics.=== The last two conventional optics designs I actually tried and tested were nightmares 1064B and 1064F, the layouts are shown in figure 1 with some thru focus diagrams. The apertures of the optics prevented making a full aperture HOE. Figure 2. is the test layout at 1.064µ which also shows the way the HOE is supposed to work and some of the best measured "spots" are shown. {| |- | [[File:fig1-1.jpg]] [[File:fig1-2.jpg]] |- | Figure 1. Construction layouts using only available conventional optics and traced spots of about 150µ. |} {| |- | [[File:fig2-1.jpg]] [[File:fig2-2.gif]] |- | Figure 2. The test set up used to measure the reconstructed point at 1.064µ and some measured spots. The space between dark parallel lines is 63 microns. Astigmatism dominates. |} These designs began to look like dead ends, as the number of elements increased, the number of possible configurations ballooned and optimization became far from obvious. It was clear that a custom made surface was the only practical solution, the two choices were a potato chip chunk of glass or a binary phase HOE. We had a lot more experience with phase HOEs so I asked Steve Arnold for help. ===Hybrid refractive / diffractive surfaces=== Steve suggested we zero out the phase error with one of his CGH nulls² placed on the flat side of a cylindrical lens, creating a hybrid optic. If the CGH were made into a binary phase structure we could have as much as 40% in the desired order. I imagine that the alternative would have been to shape a surface into something like a Pringles potato chip and attach it to the lens. Steve took my zemax generated design and plugged in the appropriate numbers to his super oslo program and went to work. There was a bit of luck going for us. The telescope mirror could be moved just a little and be made to form a line focus a comfortable distance from the cylinder, enabling us to mask out unwanted orders from the binary optic. He also found that the exit light from the lens was about 35 mm in diameter and fairly uniform, the size and uniformity was favorable for fabrication of the binary CGH and for playing it back through the system at 488 nm. The number of waves of correction was also manageable at about 160. The optimization in oslo, subsequent chrome mask generation³ and phase element fabrication went smoothly, the final assembly traced out to yield about 1 wave of higher order aberration. I also took a crack at designing the CGH in zemax but I was only able to optimize to about 4 waves (20µ spots), obviously I still have something to learn. I was much more successful at converting a chrome mask version of his oslo design into a high efficiency volume phase HOE. Simple contact copies into Dupont photopolymer⁴ yielded 30% in the 1st order, copies into UV glues diffracted up to 14%, dichromated gelatin in 25µ thicknesses grabbed 26% and unbleached silver grain films diffracted about 4% to 6%. The original chrome mask was not measured. The dichromate copies had the best optical properties. The phase only CGH from Steve, made on photoresist, measured about 18% efficiency at 488 nm and was clean and scratch free until I started using it. At this point I have done so much damage to it I will probably have to get a new cylindrical lens and bond a DCG copy of the chrome mask to it and begin again, in order to get the best possible recording. The original assembly mated fused silica to a flint glass lens, which gives rise to an interference pattern in the object beam that could be reduced by recording the DCG copy on a flint substrate, and damage in use can be minimized by capping the DCG with a thin AR coated cap of flat 7059 glass. A photo of the Hybrid optic is shown in figure 3 below, alongside of a scaled image of the pattern minus the carrier we added to it. There are 20 waves of error per fringe. {| |- | [[File:fig3-1.jpg]] [[File:fig3-2.jpg]] |- | Figure 3. The hybrid optic from Diffraction International and the CGH pattern without carrier. |} ===Modeling in zemax and in oslo=== I made an attempt to model the oslo diffractive design in zemax using the following conversion formula but I could not make it work properly. Those who are familiar with oslo or zemax will recognize some of the terms. The As are the possible 65 polynomial coefficients optimized in oslo, the Bs are the corresponding coefficients in the zemax binary 1 surface. The j+k is the sum of the powers of x and y and the quantity in brackets is a phase in waves, unique to oslo or at least not chosen in zemax. <center> <math>B_i = \rho^{(j+k)}\left[\frac{2 \pi M}{\lambda_r}\right] A_i, \text{ where } \rho = 100 \text{ if mm are chosen lens units.}]</math> </center> We need the conversion so that either model can be rearranged to accommodate another exposure geometry for this work in progress. At least 5 other designs have to be worked out and fabricated before we are done with this project. At least one of them could use the same CGH. Another improvement to the model would be an accurate representation of the B270 sheet glass substrates we are working on. The sheets appear to be consistently flat within a few waves in one direction and rippled a few more waves in the other direction, one side is usually flatter than the other, which will not matter since we are bonding two plates together with flat sides turned outward and rippled sides index matched together. The figure below shows the final recording geometry using the Hybrid optic with the diffractive part bonded to the flat backside of the refractive part. All parts were initially positioned within 1 or 2 mm of the optimized position and all angles were within about 3 mrad. Sadly, that was not close enough to produce the desired results and many adjustments have been made during trial fabrications. A three axis mount was used to position the hybrid but the parabolic mirror gave us most of the alignment trouble. {| |- | [[File:fig4.jpg]] |- | Figure 4. The final layout design using the Hybrid optic. |} ==CONSTRUCTION OF HOE== The coated plates are our own spun on dichromated gelatin⁵ (DCG) with 30 percent dichromate in a 7 - 8 micron layer of Grayslake gelatin. We age it at room temp for 2 or 3 days prior to exposure so that it will harden and reconstruct with maximum clarity. Most plates are clean and uniform and otherwise consistent and reproducible. The exposures so far were made with about 600 mwatt of 488 nm light from an argon laser and the required energy is 10 mJ/cm*cm for masters and 40 mJ/cm*cm for infrared copies. Processing is in standard IPA and water preceded by a 2 minute soak in Kodak fixer. The plates are typically cycled through each bath in 30 seconds with continuous agitation and are reprocessed as needed to get peak diffraction efficiency at 1.064µ or for masters adjusted to 50% @ 488 nm. An entirely new processing station was constructed for this project. About 50 gallons of IPA is now heated to 55 deg C with circulating hot water. The water is pumped through a remote gas water heater and stainless steel tubing looped in the bottom of each of three processing tanks, enabling economical and safe operation. Figure 5 below shows the process station and optics with mounts used during exposure. In this work we exposed 406 mm square (16 in) B270 plates with exposure times of from 4 to 16 minutes. The chance that something will warp or bend or that the laser will drift during that time is about 10:1. An electronic fringe locker was used to be certain that at least one portion of the HOE would always turn out perfectly. When all due precautions had been taken and extended settling times provided for, the results were good. All of the goals for this project have not yet been met. We will yet have to produce a contact copy from a master using apodizing techniques to get a uniform response over the entire aperture. The contact copies can also be made to meet the Bragg condition more uniformly because the angle the copy light travels in has only a small effect on the diffraction pattern but a large effect on the tilt of the Bragg planes. The best possible copy beam at 488 nm will be an astigmatic wave, produced by placing an appropriate cylindrical lens some distance in front of a pinhole. This work has yet to be done. {| |- | [[File:fig5-1.jpg]] || [[File:fig5-2.jpg]] |- | 3 hot IPA and 2 cool Water and 1 Fix tank || Optics used to form Object wave |- | colspan=2 | Figure 5. The 406 mm (16 inch) processing station and the hybrid optic with associated mounted optics. |} ==EXPERIMENTAL RESULTS== As of this writing we have achieved a slightly astigmatic spot that measures only 60µ in the direction of diffraction at the 1/e clip level and is about 70µ at the other best focus, a mm in front of the best spot. Measurements were made with a Beamscan rotating slit from Photon inc. Spot profiles were also viewed on a screen that attached to a Rhonchi rule with 63µ open spaces. The first two spots shown below in figure 6 belong to plate # 8 and meet our criteria, except for that tiny mm of astigmatism. These spots were found in a HOE that was misaligned somewhat in the Z direction, which made me suspect that one of the powered components was not made as modeled. We had modeled the mirror assuming it had a 1994 mm (78.5 inch) focal length and it is really 1999 mm (78.7 inches). I have another mirror that is 1996 mm (78.6 inch) fl and have since substituted it and moved it back slightly to account for the change. It was then that I discovered just how sensitive the system was to a tiny tilt error around the Y axis. Spots 3 and 4 from plate #13 were the result of less than .05 degree error in the tilt of the telescope mirror. Spots 5 and 6 from plate #15 are the result of translating the hybrid optic in the x direction 2 mm and tilting the mirror .5 degrees about y. Moving the hybrid optic 2 mm along the Z axis only doubles the spot size. We are going for as near to zero aberrations as we can practically get and are continuing to fine tune the set up to eliminate as many measurable flaws as possible. Unfortunately the current set up is not yet producing spots as small as the previous set up and fine tuning with big plates is extremely time consuming, nevertheless we now expect to get 60 micron spots in a finished product.</blockquote> {| |- | [[File:fig6-1.jpg]] || (best place to date) || [[File:fig6-2.jpg]] |- | #1, far focus 1016 mm || plate #8 || #2, near focus 1015 mm |- | [[File:fig6-3.jpg]] || (close second best) || [[File:fig6-4.jpg]] |- | #3, far focus 1017 mm || plate #13 || #4, near focus 1013 mm |- | [[File:fig6-5.jpg]] || (result of changing mirror) || [[File:fig6-6.jpg]] |- | #5, far focus 1016 mm || plate #15 || #6, near focus 1008 |- | Figure 6. Three sets of measured through focus spots, from 3 recent plates. Plate #8 had only 1 mm between spots, # 13 had 4 mm between and #15 had 8 mm. The space between dark bands is 63µ. |} ==ACKNOWLEDGEMENTS== We wish to thank Geary Schwemmer of NASA GSFC for sponsoring this LIDAR optics project. We also acknowledge the help of prof Thomas Wilkerson of U of MD, now at USU and of prof Stephen Bialkowski of USU for helping with analytical methods and pattern generation. The help with oslo / zemax conversion was provided by Ken Moore, author of zemax. ==REFERENCES== # R. D. Rallison and S. R. Schicker, "Wavelength compensation by time reverse ray tracing", SPIE vol 2404, p 217, 1995, San Jose, CA. # Steven M. Arnold, L. Curt Maxey, J. E. Rogers and R. C. Yoder, "Figure metrology of deep general aspherics using a conventional interferometer with a CGH null", SPIE vol 2536, July 1995. # Steven M. Arnold, "Desktop computer encoding of electron-beam written holograms" SPIE vol 884, p23, 1988. # Felix P. Shvartsman and Moshe Oren, "Photo-lithographic imaging of computer generated holographic optical elements" SPIE vol 1555, p 71, 1991. # R. D. Rallison, "Control of DCG and non silver holographic materials" SPIE vol 1600, p 26, 1991. Lake forest college, Il. ==Deleted from the original== ===Secondary HOE=== Another way to ruggedize the system and get more light in the diffracted order is to record the diffracted wavefront with a 30 degree off axis point source reference in 8 of DCG. A convenient plane to record this secondary HOE is found about 200 mm from the mask plane where the pattern is uniform and fits nicely on a 200 mm square plate. The secondary HOE replaces the Hybrid HOE in all subsequent recordings and makes exposures shorter and more likely to succeed. Alignment errors could be worse. This is an abstract submitted for the SPIE conference on Diffractive and Holographic Optics Technology III. Jan 27- Feb 2, 1996 in San Jose, CA. Copies to Steve Benton 6172538823and SPIE 2066471445 and Ivan Cindrich 3139945824 and John Trout 3026959631 Ralcon fax # 801 245 6672 Diffraction Int fax 612 945 9912 WAVELENGTH COMPENSATION AT 1.064 MICRONS USING HYBRID OPTICS Richard D. Rallison Ralcon Development Lab, Paradise UT Steven M. Arnold Diffraction International, Minneapolis MN Holographic Optics designed for use in the near IR region cannot usually be made with near IR lasers. Common recording media is naturally more sensitive to higher energy visible (blue) wavelengths. The large wavelength shift produces large aberrations. We previously made off axis focusing HOEs for 1.064 microns with blue light at 488 nm with refractive and reflective optics to reduce aberrations. We recently had success nearly nulling out those aberrations by adding a general diffractive surface to one of the refractive optics. We have reduced the errors in the IR wavefronts to a few waves over a 404 mm aperture using only off the shelf optics and a custom CGH. The method results in complete construction geometries being generated ready for implementation on a table. The general method used is time reverse ray tracing of the refracted and diffracted construction wavefronts. A 2 degree carrier is added to the phase map to separate and block unwanted diffraction orders. A binary phase HOE is then generated to diffract 35% or more of the 488 nm light into the construction path. Super OSLO and Zemax optical design programs are used to design the construction optics. ''Last modified on 6/1/99'' [[Category:Rallison]] eda29625217ad9735fff1b893c6a269564cb8769 0 855 1855 1854 2013-05-12T04:08:29Z Jsfisher 1 1 revision wikitext text/x-wiki ===Update=== Ralcon has developed a&nbsp; line of gratings that acheive near 100% diffraction efficiency at high angles, typically 46 to 48 degree half angles. These are believed to be unique because the dispersion is very high and both polarizations are diffracted equally and fall off on each side of center in the same direction. We call this new grating the Dickson grating in honor of its inventor LeRoy Dickson, a retired IBM research scientist. Manufacturing is handeled by http://wasatchphotonics.com]. A white paper on the subject of this grating and DWDM can be found in pdf format and downloaded [[Media:DWDM-Dickson_grating_white_paper.pdf|here]]. ==This is What's happening (or happened through Sept 2005)== Volume Phase Gratings (VPG) for spectrographic applications have become an important part of WPs&nbsp; business..&nbsp; WP has listed the specific gratings that have been made by frequency, wavelength, bandwidth or size and many more are for OEM&nbsp; customers. Go to their website for more detailed technical information and pricing.<br> ===General VPH information=== Most of our production gratings are between 1 inch and 8 inches on a side or diameter and work between 350 nm and 2400 nm. Most are on low iron or borosilicate sheet glass and a few are on fused silica. The largest ones are on Pilkington float glass. The gelatin layer is typically 5 to 20 microns and the spatial frequencies run from 90 l/mm to about 2000 l/mm, but can be much higher. Bandwidths are typically several hundred&nbsp; nm and are free of anomalies. The Bragg sensitivity or Blaze angle is adjustable with small tilts and the modulation can be peaked for either linear polarization or equal for both polarizations at a particular wavelength. These are very versatile gratings and come with durable AR coatings if required. The peak efficiencies are in the 90% range and the roll-off is smooth on both sides and slightly asymmetric, favoring longer wavelengths. Fractional wave performance is easily achieved with symmetrical designs(same angle in and out). Typically we expose the gratings in DCG with well collimated light on glass that is only flat to a few fringes per inch. Then if fractional wave performance is needed, the gratings can be capped with a flatter cover-glass on one or both sides. Most of the phase shifts due to uneven surfaces are index matched out in the lamination process. The final diffracted wavefront will then be well corrected and the covers also carry the AR coatings. Alternatively the plate glass can be polished flat and coated after the grating has been exposed, tuned and capped. Less frequently we coat the gelatin directly on an AR coated flat and cap with the same. Substrate sizes less than 4 inches are not good candidates for this method and we always require several extra flats so we can do a "batch" and select the best. We have a few mathcad templates for gratings design and performance analysis that can be had for the asking. We now have a Zygo phase shifting interferometer and can test diffracted wavefronts to 1/100th wave if needed. Ralcon is now in partneship with a new startup grating manufacturer called Wasatch Photonics headquartered in Logan UT. Visit http://wasatchphotonics.com for details. ''Last modified on 9/11/05'' [[Category:Rallison]] df183ec0b6e4fa6dc85b5a75c2350db767def6b4 0 596 1857 1343 2013-05-12T04:08:30Z Jsfisher 1 1 revision wikitext text/x-wiki [[Image:YDenisyuk.jpg]] Died at the age of 88 in May 2006. Yuri Denisyuk invented single beam reflection holography. ===A Memorial by Ed Wesley=== {| |[[Image:YDenisyuk2.jpg]]|| “Now maybe the girls will notice me!” quips Yuri Denisyuk, proudly displaying the Cyrillic Danger: Laser Radiation sign presented to him by the local Coherent Laser sales rep at his first visit to Lake Forest College in 1989. This is my favorite image of one the great gods of Mt. Holympus, personified as everyone’s favorite grandfather with a wacky sense of humor. After all, it was a science fiction story that inspired him to invent his own style of wavefront reconstruction! |} 23547694fa01e4436246f818676e4a704e37c097 0 597 1859 1345 2013-05-12T04:08:30Z Jsfisher 1 1 revision wikitext text/x-wiki [http://www.ultimate-holography.com/ Ultimate] f53c72dd5cf18f75124dee086093de3f6f579631 0 856 1861 1860 2013-05-12T04:08:31Z Jsfisher 1 1 revision wikitext text/x-wiki ==Zone Plate Equations== [[File:15zones.gif|right]] <strong>Variables</strong> * f = focal length * λ = wavelength * ρ_r = phase variation * r_m = radius of m<sup>th</sub> zone * m = zone number * 1 &le; N &le; ∞ <strong>Definitions</strong> * GZP = Geometric Zone Plate, paraxial, f# &gt; 10 * IZP = Interferometric Zone Plate, f# &lt; 10 * GHZP = Generalized Holographic Zone Plate <strong>Equations</strong> * For GZP: <math>r_m = \sqrt{2 m \lambda f}, \, \phi_r = \pi r^2 / (\lambda f)</math> * For IZP: <math>r_m = \sqrt{2 m \lambda f + {(m \lambda)}^2}</math> * For GHZP: <math>r_m = \sqrt{2 m \lambda f + {(m \lambda / N)}^2}</math> ==Properties of Zone Plates== * <math>\text{Minimum zone width } \simeq 2\lambda f\sharp \simeq \text{ minimum spot size}</math> * <math>\text{Depth of focus } \simeq 2 \lambda {f\sharp}^2</math> * <math>f = \frac{f_m^2}{2 m \lambda}, \, f\sharp = \frac{1}{2 N A} = \frac{f}{D i a}</math> * <math>\text{Chromatic aberration } \Delta \lambda \simeq \lambda / m</math> (m = number of zones illuminated) * Hybrid condition (f zone)/(f lens) = (n-1)/λ (dispers const.)) * Hybrid Achromats typically use GZP pattern and less than 300 zones ''Last modified on 9/22/97'' [[Category:Rallison]] c1f676adf620238c490cd4a78876130ca437a4e5 10 857 1863 1862 2013-05-12T04:08:32Z Jsfisher 1 1 revision wikitext text/x-wiki {{#if: {{{1|<noinclude>demo</noinclude>}}} | <div class="note note-{{#switch:{{{2|}}} |gotcha=error |=info |#default={{{2|}}} }}">{{{1}}}</div> | [[File:Bulbgraph.png|18px|Note|link=]]&nbsp;'''Note''': }}<noinclude> == Usage == <pre> {{note|Foo}} {{note|Foo|reminder}} {{note|Foo|error}} {{note|Foo|gotcha}} {{tip|Foo}} {{note}} Loose test {{tip}} Loose test </pre> {{note|Foo}} {{note|Foo|reminder}} {{note|Foo|error}} {{note|Foo|gotcha}} {{tip|Foo}} {{note}} Loose test {{tip}} Loose test [[Category:Templates|{{PAGENAME}}]] </noinclude> 7e966626f702a768022c74250cc9d54fe302d6d5 0 1 1864 1753 2013-05-12T04:10:41Z Jsfisher 1 wikitext text/x-wiki Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms. {{Note | This wiki is undergoing a slow and painful face lift. Please bear with us.}} [[File:Olympic.jpg|250px|right|Hologram by Tom B. The Gallery has a stereographic pair version.]] *'''[[Gallery]].''' Great examples of success, failure, and experiments. *'''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. *'''[[Beginner's Corner]].''' Basic information for getting a start in holography. *'''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. *'''[[Equipment]].''' Things used in making holograms, including some '''[[Homemade Equipment]]''' items. *'''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. *'''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. *'''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. *'''[[History of Holography|History of Holography]].''' The timeline of the people and technology. *'''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! *'''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. *'''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. *'''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. *[[Archives|Archives]] *'''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). d4d1f26b695b9c9f21d4e4b47cfc1067cefe99ec 8 858 1865 2013-05-12T04:14:49Z Jsfisher 1 Created page with "/* CSS placed here will be applied to all skins */ /** * "Note" boxes ([[Template:Note]]) */ .tip, .note { padding: 0.5em; margin: 0.5em 0; overflow: hidden; background..." css text/css /* CSS placed here will be applied to all skins */ /** * "Note" boxes ([[Template:Note]]) */ .tip, .note { padding: 0.5em; margin: 0.5em 0; overflow: hidden; background-color: #F9F9F9; background-position: 4px 2px; background-repeat: no-repeat; border: 1px solid #DDD; } .tip-info, .note-info { background-color: #F0F0E7; background-image: url(//upload.wikimedia.org/wikipedia/commons/thumb/f/f8/Appunti_architetto_franc_01.svg/22px-Appunti_architetto_franc_01.svg.png); border-color: #cc9933; /* @noflip */ padding-left: 30px; min-height: 28px; } .tip-reminder, .note-reminder { background-color: #F6FDEA; background-image: url(//upload.wikimedia.org/wikipedia/commons/thumb/6/60/Bulbgraph.png/23px-Bulbgraph.png); border-color: #D6E434; padding-left: 31px; min-height: 28px; } .tip-error, .note-error { background-color: #F0E7E7; background-image: url(//upload.wikimedia.org/wikipedia/commons/thumb/5/51/Attention_niels_epting.svg/24px-Attention_niels_epting.svg.png); border-color: #cc3333; padding-left: 32px; min-height: 25px; } 0c891512103eb4de18569c36a168bdf73324c066 6 859 1866 2013-05-12T04:16:29Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 14 860 1867 2013-05-12T04:18:16Z Jsfisher 1 Created page with "Richard Rallison was a pioneer in exploring the use of dichromated gelatin in holography. He chronicled many of his findings and wisdom on the Ralcon Development Labs web sit..." wikitext text/x-wiki Richard Rallison was a pioneer in exploring the use of dichromated gelatin in holography. He chronicled many of his findings and wisdom on the Ralcon Development Labs web site. Ralcon Development Labs in operation, and with the untimely death of Rallison, his postings might have been lost forever had it not been for the [[http://archive.org/web/web.php Internet Archive Wayback Machine]]. Articles indexed below were retrieved from the Wayback Machine. 793f12629d7cd6d0230f7026baa05e6be0c51640 1868 1867 2013-05-12T04:18:34Z Jsfisher 1 wikitext text/x-wiki Richard Rallison was a pioneer in exploring the use of dichromated gelatin in holography. He chronicled many of his findings and wisdom on the Ralcon Development Labs web site. Ralcon Development Labs in operation, and with the untimely death of Rallison, his postings might have been lost forever had it not been for the [http://archive.org/web/web.php Internet Archive Wayback Machine]. Articles indexed below were retrieved from the Wayback Machine. d1225874a2f296c686f306e9d6404d82f1b6bb78 6 292 1869 468 2013-05-12T04:20:19Z Jsfisher 1 Jsfisher uploaded &quot;[[File:CIEDiagram.jpg]]&quot; wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 861 1870 2013-05-12T04:21:50Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 862 1871 2013-05-12T04:22:18Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 863 1872 2013-05-12T04:22:35Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 294 1873 480 2013-05-12T04:24:36Z Jsfisher 1 Jsfisher uploaded &quot;[[File:Colinemail.gif]]&quot; wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 804 1874 1561 2013-05-12T04:32:50Z Jsfisher 1 wikitext text/x-wiki [[Category:DCG]] [[Category:Beginner]] [[Category:Pecora]] By: [[John Pecora]] (Note: as this is an original article please do not edit it unless you are John. Please use the discussion page to comment on this work.) ==Abstract== As the availability of green lasers becomes cheaper and more widespread, so does the potential for one to make their own dichromated gelatin (DCG) film and holograms. The purpose of this paper is to provide a basic step-by-step set of procedures such that the beginner may have success in producing their own DCG film and making simple DCG Holograms. There are many variables in the fabrication and processing which alter the aesthetics of a DCG hologram, most of which will be beyond the scope of this paper. And the basics here will not guarantee a professional quality hologram but will lead the reader down one correct path to successfully make DCG film and DCG holograms. It will be up the reader to take the next steps to perfect the quality and repeatability of the DCG hologram process. == Introduction == DCG emulsion is made from a simple solution of ammonium (or potassium) dichromate, raw gelatin and water. Exposure to the DCG emulsion is done in the Green or Blue with higher sensitivity to the shorter wavelengths. Processing is simply a soak in Standard Photographic Fixer followed by a soak in water followed by a dehydrating process in one or more alcohol concentration baths. As a DCG hologram is susceptible to image loss when exposed to moisture, the DCG hologram will be sealed. There is a multitude of ways to perform each of these functions and the ones presented here have been tried and prove to work but may not be the best or suit a particular application for the DCG hologram. '''Also, it is very important to insure safety at each step of of the process using good chemical safety practices, knowledge of the chemicals and equipment being used, proper disposal of chemicals, and common sense.''' It is not within the scope of this paper to point out safety hazards and it is the responsibility of the reader to research each and every potential safety hazard. I also suggest reading the entire paper first to familiarize your self with the procedures and note any materials and supplies you may need. ==Glass Preparation== Cleaning the glass properly is important. If the glass is not cleaned properly the emulsion can lift off the glass in spots or completely during processing. Also, if there are any dust particles, the emulsion tends to have different properties at that area and a circular ring of deformation of the hologram will be seen around that area. Soak the glass in a 3% concentration of hydrochloric acid overnight. This can be bought as muriatic acid from most home improvement centers. You could also use a 25% concentration of household bleach. This procedure also works for recycling glass from previously coated plates, but I found the bleach takes longer. After soaking, using rubber gloves, scrub the plates with a plastic wool scrubby used for cleaning Teflon pans. Steel wool may scratch the glass. After scrubbing rinse the glass thoroughly under running water and place in a tray of running water. Then repeat the rinse process while rubbing again with the plastic wool. After the final rinse, lean the plates against the wall on a paper towel. Before the plates dry completely use a paper towel to dry off one plate at a time and continue to turn the paper towel until the plate is dry. You will hear and feel the difference between a damp plate and a dry one. Repeat for the other side of glass. Do not touch the plate with your skin or oils will be left behind which can also cause the emulsion not to stick to the glass. ==DCG Emulsion Fabrication== DCG emulsion is comprised of an amount of distilled water, dry gelatin and ammonium (or potassium) dichromate. A good starting formula is 100:12:3 for the procedures described here. Take the water and place it in a heat resistant glass or plastic container. Place this on a magnetic heater/stirrer or in a double boiler. Add the gelatin to the water while it is cool and allow it to mix for a couple of minutes. If you are not using a heater/stirrer the stirring should be done by hand. Bring the temperature up slowly to a maximum of 120°F and a minimum of 110°F. Once the solution reaches the 110°F temperature, continue mixing until the gelatin mixture is completely dissolved. With the heater/stirrer allow the solution to be well mixed the entire time but not so fast as to cause excessive bubbles or foam. By hand, mix well for one minute every 5 minutes (this get laborious by hand). Mixing too long is better then under mixing, and I suggest 45 minutes after the minimum temperature is reached for a more aesthetic hologram. But again shorter times may be used as long as the gelatin is dissolved. It will look very clear and not cloudy when dissolved with no suspended particles. '''From this point on, a safelight must be used until the after the water bath in processing.''' A good safelight to use is a standard yellow incandescent bug light. Now add the dichromate. Allow this to mix until it is all dissolved (about 15 minutes) within the same temperature range. When this is completed, filter the mixture through a paper coffee filter into a clean container. A funnel or similar can be used to hold the coffee filter paper. It is best to allow the narrow end of the funnel to touch or be very close to the bottom of the final pouring container such that dripping from the funnel end does not produce bubbles. The container can be a beaker or other similar container that can easily be poured from but at the same time can be put back on the heater/stirrer or back in the double boiler to maintain the previous temperature range. If the emulsion is cooler during coating the final emulsion thickness will be thicker. Take a Q-tip and pop or remove any small bubbles that may be on the emulsion. The emulsion is now ready to coat. The emulsion can be stored at this time in a refrigerator, but should be sealed, labeled, and not allowed to be exposed to light. ==Plate Coating== The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120°F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70°F). Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45 degree angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly, you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. Take the plate and immediately place it on a table and spin it as 78 RPM. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. I prefer the spin method. If you run out of emulsion in the pouring container, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. ==Exposing the Plate== The plate is best after 4 hours old and can be up to a week(s) old. I have found the brightest holograms are between the 4 and 12 hour age. It seems when plates are older they are harder to get broadband replay and/or replay into shorter wavelengths and lose some sensitivity. The simplest recording geometry is a [[Single Beam Reflection]] in which the object is lying down on its back and the plate is laid right on top of the object. Make sure the object and plate do not wobble. Place the emulsion facing the object. As DCG is quite relaxing in the energy requirements I suggest doing test exposures with the times being doubled thus covering the largest range of times in the least amount or test exposures. Once the time range is found with your laser it will be easy to reproduce. An example is 10 seconds, 20 seconds, 40 seconds, 80 seconds, and 160 seconds. After exposure allow the plate to set in complete darkness for 2 to 5 minutes before processing. ==Processing the Plate== All temperatures can be at room temperature (70°F). Take the plate and put it in Kodak Rapid Fixer with hardener. The Fixer should be mixed as per the instructions for the most dilute mixture (paper 1:7). Gently rock the tray until all yellow is gone then an additional 15 seconds. This should take anywhere from ½ minute to 2 minutes. I use a white tray to observe the yellow more easily. Once this is completed, place the plate in running water for 5 minutes (a tray of water can be used if running water is not available). I now turn on a quartz halogen light that shines on the spot where I will lean the hologram to blow it dry. Then take the plate and place it in 35% alcohol for 15 seconds. Then 70% alcohol for 15 seconds, then 91% alcohol for 15 seconds then finally 100% alcohol until diffraction is visible (anywhere from 15 seconds to two minutes or longer). As soon as diffraction (colors) is seen, allow another 15 seconds in that bath. Then take the plate out and lean it against the wall in the overhead light. With practice you will find which angle the diffraction is seen in the light and which way that relates to the visibility of the hologram when blow drying it. As soon as you lean the plate against the wall begin blow drying it with a hair dryer set on its hottest and strongest settings. Blow dry very close to the plate. Start at the center and in a circular motion move to the outside of the plate and repeat often. If the plate is leaning the right way the diffraction and image should start to get really bright. Continue drying until hologram in completely dry. You cannot over dry but you can under dry. This usually takes me 5 minutes minimum. ==Sealing the Hologram== If the hologram is acceptable in quality and brightness to your liking, it must be sealed against moisture. After it is completely dry, use a razor to scrap off ¼" of emulsion from around all four edges. Three edges will be easy if you maintained ¼" when pouring the coating. The bottom wiped edge from coating will probably need the most attention. Now have another cleaned piece of glass ready the same size as the hologram. Mix up some 5 minute 2-part epoxy. I use a Q-Tip with the swab cut off. Now take the Q-Tip and use it to lay down a bead of epoxy around the entire cleaned edge on the emulsion side of the hologram. Take the clear cleaned piece of glass and place it over the hologram. You should see the epoxy sandwiched between the glass plates at the edge where the emulsion was scraped. Look closely and make sure there are not voids where the epoxy did not get sandwiched. Let the plates dry horizontally and check often to make sure the top plate does not slide and move into a different location. After about 15 minutes the hologram can be displayed as liked. fb5391f65a4e0d5c20152fe0f635cbf44c77a602 0 1 1875 1864 2013-05-12T04:44:52Z Jsfisher 1 wikitext text/x-wiki Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms. {{Note | This wiki is undergoing a slow and painful face lift. Please bear with us.| gotcha}} [[File:Olympic.jpg|250px|right|Hologram by Tom B. The Gallery has a stereographic pair version.]] *'''[[Gallery]].''' Great examples of success, failure, and experiments. *'''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. *'''[[Beginner's Corner]].''' Basic information for getting a start in holography. *'''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. *'''[[Equipment]].''' Things used in making holograms, including some '''[[Homemade Equipment]]''' items. *'''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. *'''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. *'''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. *'''[[History of Holography|History of Holography]].''' The timeline of the people and technology. *'''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! *'''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. *'''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. *'''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. *[[Archives|Archives]] *'''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). 41a8b3c54e54ad545e6331b6c50ad62154c36666 1880 1875 2013-05-12T05:40:00Z Jsfisher 1 wikitext text/x-wiki Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms. {{Note | This wiki is undergoing a slow and painful face lift. Please bear with us.| gotcha}} [[File:Olympic.jpg|250px|right|Hologram by Tom B. The Gallery has a stereographic pair version.]] * '''[[Gallery]].''' Great examples of success, failure, and experiments. * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Equipment]].''' Things used in making holograms, including some '''[[Homemade Equipment]]''' items. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * [[Archives|Archives]] * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). efc07b9f3dfb3e2c6af3c3a3268f6a585a2c8d7e 1907 1880 2013-05-14T00:58:24Z Jsfisher 1 wikitext text/x-wiki Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms. {{Note | This wiki is undergoing a slow and painful face lift. Please bear with us.| gotcha}} [[File:Olympic.jpg|250px|right|Hologram by Tom B. The Gallery has a stereographic pair version.]] * '''[[Gallery]].''' Great examples of success, failure, and experiments. * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * [[Archives|Archives]] * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). 331909b50e57c89448b1f01fd6aeec2f57a9be35 0 831 1876 1705 2013-05-12T04:47:17Z Jsfisher 1 wikitext text/x-wiki Also see a sample of [[Equations|common DOE surfaces]]. *Complete Spectrograph designs and brassboard prototypes, diffractive component production for the same *Transmission gratings from 10 to 4000 l/mm, plane, slanted, crossed, cophasal, multiplexed spatially or stacked in volume from spectroscopic instrument to light show quality, in DCG, photopolymer, resist or plastic replicas. *Powered transmission HOEs of f/2 or greater with low aberrations, apertures to 1 meter and wavelengths from 355 to 1064 nm, for LIDAR applications. *Off axis Multifocus hololens and flys eye arrays, optical interconnects and general multiplexed powered optics. ==== "Catadioptric HMD" ==== {| |- |[[Image:cathyb1.gif|center]] | *Narrow Notch filters from 400 to 900 nm, 10 to 40 nm bandwidth, Optical densities to 5 or 6 in 30 microns of DCG. *[[Directional diffusers]], dipixelators and homogenizers in virtually any configuration, (design, fabrication, and production). *HUD and HMD components including conformal multiwavelength combiners on CR 39 or glass of any radius. *TIR gratings for photon buckets, edge lighting, polarizing. |} ==== "Transmissive Grating Spectrograph" ==== {| |- |[[Image:graph3.gif|center]] | *Bidiffringent polarization separator that works in a Wollaston configuration and broadband planer polarization splitters. *Complete ZEMAX optical designs including binary surfaces, masks and phase only replicas in volume or surface media. *Hybrid refractive/diffractive design and fabrication. |} ==== "Powered Laser Scanner" ==== {| |- |[[Image:graph4.gif|center]] | *In-house lithographic photoreduction for some DOE production. *Conversion of customer generated amplitude masks to efficient phase DOEs and HOEs. *IR gratings for 3 to 12 microns in slumped amorphous IR glasses. *Addition of high frequency carriers to low angle CGHs. |} '''The odds are in your favor, that we can make the HOE you need.''' == Advantages of DOEs == #Simultaneous performance of several functions such as [[Equations#Holographic Deflectors (hologons)|deflection]], focusing, filtering, and collimating as in bar code scanners. #Parallel performance of similar or different functions such as the multifocus Hololens array for parallel pattern recognition. #Ease of stacking elements such as multi-wavelength solar reflectors. #The formation of optics on curved substrates such as heads up displays on visors or curved windshields. #Weight and volume of a holographic system is likely to be less than refractive optics, especially for large apertures. #Ease of replication makes production fast, inexpensive and relatively simple. '''''Last modified on 9/16/97''''' [[Category:Rallison]] 3ea843abcba6da5901e149921fc9732b76bebfb9 6 864 1877 2013-05-12T05:22:22Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 865 1878 2013-05-12T05:33:23Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 866 1879 2013-05-12T05:38:27Z Jsfisher 1 Created page with "Holography has a wealth of possibilities for the amateur and professional holographer, alike. == Ferric Ammonium Oxalate == {| |- | Ferric ammonium oxalate (FAO) and possibl..." wikitext text/x-wiki Holography has a wealth of possibilities for the amateur and professional holographer, alike. == Ferric Ammonium Oxalate == {| |- | Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in two Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 and http://holoforum.org/forum/viewtopic.php?f=7&t=497 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] |} cb8c4a9c1058ccb73a42f209b2b2f4298f80862c 1881 1879 2013-05-12T13:42:18Z Jsfisher 1 wikitext text/x-wiki Holography has a wealth of possibilities for the amateur and professional holographer, alike. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in two Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 and http://holoforum.org/forum/viewtopic.php?f=7&t=497 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} 7b0ec325e977aaef8252a22146a8404296ad66e9 1903 1881 2013-05-13T22:32:22Z Jsfisher 1 wikitext text/x-wiki Holography has a wealth of possibilities for the amateur and professional holographer, alike. == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special view is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in two Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 and http://holoforum.org/forum/viewtopic.php?f=7&t=497 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} 08d23c24bf5876b908c3743465720ec3f440b2c4 1904 1903 2013-05-13T22:38:53Z Jsfisher 1 wikitext text/x-wiki Holography has a wealth of possibilities for the amateur and professional holographer, alike. == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in two Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 and http://holoforum.org/forum/viewtopic.php?f=7&t=497 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} e4dfcab188f3c6db74573f548a425d167a736f93 1905 1904 2013-05-14T00:47:07Z Jsfisher 1 /* Ferric Ammonium Oxalate */ wikitext text/x-wiki Holography has a wealth of possibilities for the amateur and professional holographer, alike. == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in two Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 and http://holoforum.org/forum/viewtopic.php?f=7&t=497 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were three days exposed after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} 4ccb84278edc81b6e4c58b16191bbdc83822c1a8 1906 1905 2013-05-14T00:47:57Z Jsfisher 1 /* Ferric Ammonium Oxalate */ wikitext text/x-wiki Holography has a wealth of possibilities for the amateur and professional holographer, alike. == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in two Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 and http://holoforum.org/forum/viewtopic.php?f=7&t=497 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} 4056bdc86d14e485a8afe4f8a4f0790fe4b2231e 0 500 1882 1807 2013-05-12T16:13:13Z Jsfisher 1 Improve table appearance wikitext text/x-wiki {| align="center" border="1" |- | align="center" rowspan="2" | '''''Material''''' | align="center" rowspan="2" | '''''Thickness (um)''''' | align="center" rowspan="2" | '''''Spectral Sensitivity (uJ/cm²)''''' | align="center" colspan="4" | '''''Sensitivity (uJ/cm²)''''' | align="center" rowspan="2" | '''''Resolving Power (lines/mm)''''' | align="center" rowspan="2" | '''''Grain Size (nm)''''' |- | align="center" | '''''442 nm''''' | align="center" | '''''514 nm''''' | align="center" | '''''633 nm''''' | align="center" | '''''694 nm''''' |- | colspan="9" | '''Slavich''' |- | PFG-01 | align="center" | 7 | align="center" | &lt;700 | | | align="center" | 80 | | align="center" | &gt;3000 | align="center" | 35-40 |- | PFG-03M | align="center" | 7 | align="center" | &lt;700 | | | align="center" | 1500 | | align="center" | &gt;5000 | align="center" | 10-20 |- | VRP-M | align="center" | 7 | align="center" | &lt;550 | | align="center" | 80 | | | align="center" | &gt;3000 | align="center" | 35-40 |- | PFG-03C | align="center" | 9 | align="center" | 400-700 | align="center" | 1000 | align="center" | 2000 | align="center" | 1000 | | align="center" | &gt;5000 | align="center" | 10-20 |- | colspan="9" | '''Colourholographic''' |- | BB-700 | align="center" | 7 | align="center" | &lt;700 | | | align="center" | 50 | align="center" | 150 | align="center" | &gt;2500 | align="center" | 50-60 |- | BB-640 | align="center" | 7 | align="center" | &lt;650 | | | align="center" | 150 | | align="center" | &gt;4000 | align="center" | 20-25 |- | BB-520 | align="center" | 7 | align="center" | &lt;540 | align="center" | 150 | align="center" | 150 | | | align="center" | &gt;4000 | align="center" | 20-25 |- | BB-450 | align="center" | 7 | align="center" | &lt;470 | align="center" | 150 | | | | align="center" | &gt;4000 | align="center" | 20-25 |- | colspan="9" | '''Kodak''' |- | 131PX | align="center" | 9 | align="center" | &lt;650 | align="center" | 2 | | align="center" | .5 | | align="center" | &gt;1250 | align="center" | 70 |- | 131CX | align="center" | 9 | align="center" | &lt;650 | align="center" | 2 | | align="center" | .5 | | align="center" | &gt;1250 | align="center" | 70 |- | 120PX | align="center" | 6 | align="center" | &lt;750 | align="center" | 60 | | align="center" | 40 | align="center" | 40 | align="center" | &gt;1250 | align="center" | 70 |- | 120CX | align="center" | 6 | align="center" | &lt;750 | align="center" | 60 | | align="center" | 40 | align="center" | 40 | align="center" | &gt;1250 | align="center" | 70 |- | colspan="9" | '''FilmoTec-ORWO''' |- | GF40 (gelatin film) | align="center" | 6 | align="center" | UV to blue-green after sensitization | | | | | align="center" | not relevant | |- | HF53 | align="center" | 6 | align="center" | &lt;550 | | align="center" | 1000 @ 535 nm | | | align="center" | &gt;5000 | |- | HF55 | align="center" | 6 | align="center" | &lt;550 | | align="center" | 250 @ 535 nm | | | align="center" | &gt;3000 | |- | HF65 | align="center" | 6 | align="center" | 580 to 660 | | | align="center" | &lt;100 | | align="center" | &gt;3000 | |- | colspan="9" | '''Ultimate''' |- | Ultimate 15 | align="center" | 7 | align="center" | &lt;700 | | align="center" | 150 | align="center" | 150 | align="center" | 150 | align="center" | &gt;5000 | align="center" | 15 |- | Ultimate 08 | align="center" | 7 | align="center" | &lt;650 | align="center" | 120 | align="center" | 200 | align="center" | 200 | | align="center" | &gt;7000 | align="center" | 8 |- | colspan="9" | '''Fuji''' |- | HL-30 | | align="center" | 100-200 | | | | | align="center" | 3000 | align="center" | 30-40 |} f647d2ceb2c0b6867979a75a8e854794a05aae82 0 270 1883 1707 2013-05-12T16:21:09Z Jsfisher 1 wikitext text/x-wiki [[Image:CIEDiagram.jpg]] Holograms need a material to record interference fringes. There are many materials that can record fringes. * '''[[Silver Halide Materials]]:''' Basic information about silver halide holographic plates and film. * '''[[Silver Halide Chemistry]]:''' Theory and Practice of Making Silver Halide Plates and Development. * '''[[Silver Film Comparison Chart]]:''' A quick comparison of the qualities of different commercially made films. * '''[[Dichromated Gelatin Chemistry]]:''' Theory and Practice of DCG Plates and Development. * '''[[Polymer Film and Processes]]:''' Many commercially sold holograms are made from photopolymers. * ''' [[Photoresist]]:''' Taken from the electronics industry, this material can make relief holograms for embossing. * '''[[Coating Methods]]:''' Coating Gelatin on to a glass plate is an art in itself. * '''[[Crystals]]:''' There are many crystals that can record an image. The cost and exposure energy required is very high so they are not often used for holography. * '''[[Embossed Holograms]]:''' These are like the holograms seen on credit cards. * '''[[Gelatin]]:''' Used as the suspension medium to hold light sensitive particles. * '''[http://en.wikipedia.org/wiki/Hologram#Materials Wikipedia]:''' Wikipedia's summary of Holographic Recording Materials. * '''[http://en.wikipedia.org/wiki/Periodic_table_%28standard%29 The Elements]:''' The Periodic Table of the Elements * '''[[Books]]''' 860dddcdab7925bbd63545fb6f61d4de0a386a68 0 489 1884 1129 2013-05-12T16:54:37Z Jsfisher 1 wikitext text/x-wiki This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> 9769c8247d6af9ccdf70f292d20d9ed08b1887f6 1885 1884 2013-05-12T18:08:27Z Jsfisher 1 wikitext text/x-wiki This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> ==Gallery== <gallery> File:fred.JPG File:Bulbgraph.png File:fred77.jpg|Caption1 File:Hugo_Spatial_Filter.jpg|Caption2 </gallery> d6b049620793ba12d646e0aaf23d8d388171a1c7 1886 1885 2013-05-12T18:13:40Z Jsfisher 1 wikitext text/x-wiki This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> 6426af6887fcd1aa7faabbd22ed91d7fcc8e554b 1890 1886 2013-05-12T19:01:03Z Jsfisher 1 wikitext text/x-wiki This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y}</math> <math>\textstyle \frac{x}{y}</math> <math>\scriptstyle \frac{x}{y}</math> <math>\scriptscriptstyle \frac{x}{y}</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> 86a825ecad1b0214e5cb0209f1fc530ccb147119 1909 1890 2013-05-14T01:51:07Z Jsfisher 1 wikitext text/x-wiki http://abc.def.com/asdf Text <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y}</math> <math>\textstyle \frac{x}{y}</math> <math>\scriptstyle \frac{x}{y}</math> <math>\scriptscriptstyle \frac{x}{y}</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> 6a43caafc86e1e8756dc437164cfb4e2cdd1936b 6 293 1887 470 2013-05-12T18:27:25Z Jsfisher 1 Jsfisher uploaded &quot;[[File:Citric.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 179 1888 1605 2013-05-12T18:28:45Z Jsfisher 1 wikitext text/x-wiki The Blyth Colour Tuning method originated from an observation Jeff posted to the forum and its testing was taken up by a number of people. The results were very promising. The original thread is here: [http://www.holographyforum.org/phpBB2/viewtopic.php?f=2&t=5224 Blyth Colour Tuning Thread] ==Preperation== Stock Solution: *15g Citric Acid *100ml Water Dilute as needed. Soak the hologram to be swelled for 30 minutes. Then dry. Amazingly squeegee technique is not very important here! ==Paulos Test== I cut a 15 x 20 cm film hologram in 4 pieces and applied Jeff's Citric Acid solution method. The result: # (upper left): untreated (514 nm) # (upper right) 11.75 % Citric Acid (=15% x 0.75) # (down left) 7.5 % Citric Acid (=15% x 0.5) # (down right) 15 % Citric Acid {{note | Based on the progression of color shifts, #2 and #3 may have been reversed with respect to acid concentration in the original article. | gotcha}} [[Image:citric.jpg]] The photo is not the best one (the hologram is free of any noise), but the effect of the various concentrations is obvious. In comparison to sorbitol-treated holograms, the overall quality is better. * Exposure at 514 nm * Holographic film: Finegrained HF-53 from ORWO * This emulsion is much harder than Slavich material. ==Theory== From Jeff Blyth I have been doing a bit more on this since I have receiving an appreciative email from Rob Taylor (Forth Dimension Holographics) about the newly found virtues of the citric acid post swell system.. In it he mentions how forgiving it is to the squeegeeing. technique. I have noticed this too and have just been wiping off the excess citric acid solution casually with tissues and have not seen smeary streaks of darker red which would have occurred with sorbitol solution. Now this convenient fact indicates something about what is happening down at the molecular level. Also I just might possibly have discovered something of interest for DCGers to investigate as a means of changing those finished too-blue colored hologram into red ones –a trick which I think John Pecora has discussed more than once on this Forum over recent years. However with only 2 days of observation I am being rather optimistic to think I have a long term answer to that old perennial DCG problem but I hope that DCG’ers will now try some experiments with old “Bluies and Greenies” as John puts it before just recycling the glass! I will go into a bit of DCG detail at the end of this post. First though I need to hypothesize what is happening at the molecular level to try to understand the observation about squeegeeing technique being less critical with citric acid solution compared to sorbitol or glycerol solution. So as we all know, the building bricks of gelatin are amino acids. In neutral pH conditions these make themselves into internal acid–base structures with the negative – positive ions neutralising each other. The swelling in water is caused by both the positive and negative ions choosing to open themselves up to accommodating lots of water molecules which take on partial induced charges opposite to the ions they surround. So the amino positive ions get surrounded by a cloud of partially negatively charged water molecules and vice versa around the negatively charged acid groups . This allows the original electrostatic attraction between the oppositely charged components of the amino acid to slacken and the components to move apart by a factor of 2 or 3 times their unswollen distance. An accepted way of keeping gelatin based holograms swollen with water has been to try to replace a lot of the water with non- volatile very hydrophilic “polyalcohols” such as glycerol or sorbitol . These alcohols get involved in the cloud of water molecules surrounding the charged amino acid groups. The size of this cloud of water molecules around the oppositely charged amino acids is very imprecise , variable and dynamic, (this description will be important), it instantly can change with temperature and humidity changes so it is difficult to control color changes of gelatin based reflection holograms. (They act as superb humidity change sensors---a fact I am personally gaining from in the development of “Smart” holograms to test for water in aviation fuel.).. Just breathing on them can make a wavelength change of tens of nanometers as we all know. However in the case of a hologram treated with citric acid and then blow dried at room temperature we are left with a swollen gelatin which is different from the case of one swollen with water plus sorbitol or glycerol. In citric acid we have in effect the line of 3 carbons in glycerol now with their alcohol groups (-OH) replaced by carboxylic acid groups (-COOH) except for the central carbon which has the (-COOH) added in place of H leaving one alcohol OH still there (more on this later). These –COOH groups introduce a different effect to cause the swelling of the gelatin. This time the citric acid (-COOH) groups can partially displace the original internal (-COOH) groups from their attraction to the amino groups. These displaced (-COOH) groups are still firmly attached to the gelatin biopolymer of course and are not free to wander off in solution so the rest of the citric acid molecule is forced to be accommodated into the gelatin structure as most of the surrounding water is now evaporated off thus leaving the gelatin in a swollen state when it is left to equilibrate with ambient humidity.--- Fortunately it is a chemically weak arrangement easily completely reversed by plenty of fresh water so that it becomes energetically more favourable for all the ions involved to go back to surrounding themselves with water-molecule clouds again . The upshot of this is that if you are not satisfied with the color of your treated hologram you can go back to square one without any difficulty . I have not found the slightest trace of the effect of citric acid after rewashing in water. --An important feature for any precious holograms whose color you are trying to tweak. In the above model one can sense why the removal of excess surface liquid on a hologram treated with citric acid solution is more forgiving (in the final result) from an unequal treatment with a squeegee blade compared to the same situation with an excess of sorbitol solution. In the case of excess sorbitol that final sheath or cloud of water/sorbitol molecules which I described above as "very imprecise , variable and dynamic", as they surround the amino acid ions they can be far too sensitive to small variations in residual water causing corresponding local variations in reddening of the final replay color as the clouds expand or contract. Whereas in the case of the citric acid, the reddening is caused mainly by a specific alteration of the internal molecular structures of the amino acids and perhaps not much by a variable cloud around the ion.. Now experienced DCGers have long since found that you cannot change the color of a finished too-blue DCG by playing around with sorbitol treatment. Anything that attracts water is anathema to DCG holograms. So the question naturally arises can one somehow do it with this different citric acid mechanism? Well I took a blue green finished DCG , left it in 10% citric acid for 10 mins, (I cut the time down from my previous 30 min recommendation because I noticed the gelatin was starting to come off the glass after 5 mins) I then briefly wiped it with a tissue an plunged it into a stirred beaker of ~100% ipa at room temperature. ( I needed to avoid using ipa/water solution as it was likely to loose citric acid. The acid fortunately seemed to prefer to keep its weak attraction to the gelatin rather than dissolve in ipa. only). The good news is that the resulting hologram after a long cool blow was a deep red hologram instead of a blue green one. But the bad news is that that only 3 hours later it had vanished.. But ……don’t go away yet…………. I tried a variant. …… The problem was of course likely to be too much water attracted in still--the water cloud around ions was probably still there to some extent which caused the air- void fringe structure to be unstable and disappear. So could an improvement be got by using an alternative organic acid without a residual alcohol –OH group still present? So I tried succinic acid instead. This is a non- poisonous but quite strong organic acid (a “natural” product too) with the 2 alcohol groups in ethylene glycol replaced by –COOH groups. I found that it saturated at room temperature at around the 6% level but treating green silver halide holos with it did make useful color shifts to yellow (in the case of BB plates but not in the case of the harder Fuji film,) it was though much less effective at causing the amount of color shift you can get from the same concentration of citric acid. The question is then is this less hydrophilic acid able to keep a color shift in DCG? So far my test sample is still maintaining its green to orange shift after 36 hours but I would not put any money on its permanence. So I am hoping some DCGer will pick the idea up, get in a bit of succinic acid and play around with sealing it up etc. ---it could be an interesting alternative to recycling those “Bluies”. Jeff 1a03e062748aa46889f9d70563c5eacbb344a651 0 824 1889 1673 2013-05-12T18:58:55Z Jsfisher 1 wikitext text/x-wiki == Common DOE surfaces == === Sinusoidal, triangle === {| |[[Image:Sine.gif|left]]<br> | *Max D.E. ~ 30% ± 1 order *Power distribution follows Bessel function in the scaler region. *T ≈ λ for transmission. *T ≈ λ/4 for reflection. *Easily replicated or deep etch can yield higher efficiency. |} === Square, rectangle === {| |[[Image:Square.gif|left]] | *Max D.E. ~ 40% ± 1 order. *Power distributions favors odd orders. *Pi phase shift typical. *Classic binary grating. *T ≈ λ for transmission. *T ≈ λ/4 for reflection. |} === Blazed, sawtooth === {| |[[Image:Blazed.gif|left]] | *Max D.E ~ 98% *Reflection Case: **λ = 2 d sin a **T = λ/2 ± 10% *Transmission Case: **λ = d sin b **a ≈ 2b **T = λ/(n-1) ± 10% **Surface shadows reduce D.E. by <math>\lambda^2 / n d^2</math>&nbsp;[[Image:Equ1.gif]] **Wavelength changes reduce D.E. by <math>(\pi\Delta\lambda / b\lambda)^2/</math>&nbsp;[[Image:Equ2.gif]] |} == Holographic Deflectors (hologons) == {| |[[Image:Scan.gif|left]]<br> | *N = θD/(1.4λ) *N = number of resolvable spots *θ = full scan angle in radians *D = beam diameter in microns *λ = wavelength *Φ = wedge angle of glass *Special case of linear scan and near wobble invariance a ~ b ~ 45° max straight scan angle ~ 36° *Dynamic wobble <math>\simeq \Delta\Omega/128</math> *Wedge wobble = (n-1)Φ *Scan angle multiplier = 1.4 @ 90° cross scan angle |} '''''Last modified on 9/29/97''''' [[Category:Rallison]] 722b58fa8df460b58995d38607ed5dd44388e166 1891 1889 2013-05-12T19:05:11Z Jsfisher 1 wikitext text/x-wiki == Common DOE surfaces == === Sinusoidal, triangle === {| |[[Image:Sine.gif|left]]<br> | *Max D.E. ~ 30% ± 1 order *Power distribution follows Bessel function in the scaler region. *T ≈ λ for transmission. *T ≈ λ/4 for reflection. *Easily replicated or deep etch can yield higher efficiency. |} === Square, rectangle === {| |[[Image:Square.gif|left]] | *Max D.E. ~ 40% ± 1 order. *Power distributions favors odd orders. *Pi phase shift typical. *Classic binary grating. *T ≈ λ for transmission. *T ≈ λ/4 for reflection. |} === Blazed, sawtooth === {| |[[Image:Blazed.gif|left]] | *Max D.E ~ 98% *Reflection Case: **λ = 2 d sin a **T = λ/2 ± 10% *Transmission Case: **λ = d sin b **a ≈ 2b **T = λ/(n-1) ± 10% **Surface shadows reduce D.E. by <math>\textstyle \frac{\lambda^2}{n d^2}</math> **Wavelength changes reduce D.E. by <math>\scriptstyle \left(\frac{\pi\Delta\lambda}{b\lambda}\right)^2</math> |} == Holographic Deflectors (hologons) == {| |[[Image:Scan.gif|left]]<br> | *N = θD/(1.4λ) *N = number of resolvable spots *θ = full scan angle in radians *D = beam diameter in microns *λ = wavelength *Φ = wedge angle of glass *Special case of linear scan and near wobble invariance a ~ b ~ 45° max straight scan angle ~ 36° *Dynamic wobble <math>\scriptstyle \simeq \Delta\Omega/128</math> *Wedge wobble = (n-1)Φ *Scan angle multiplier = 1.4 @ 90° cross scan angle |} '''''Last modified on 9/29/97''''' [[Category:Rallison]] d01eb9b6b046512cb415689d57e53cbd95a2ad1b 1892 1891 2013-05-12T19:05:57Z Jsfisher 1 wikitext text/x-wiki == Common DOE surfaces == === Sinusoidal, triangle === {| |[[Image:Sine.gif|left]]<br> | *Max D.E. ~ 30% ± 1 order *Power distribution follows Bessel function in the scaler region. *T ≈ λ for transmission. *T ≈ λ/4 for reflection. *Easily replicated or deep etch can yield higher efficiency. |} === Square, rectangle === {| |[[Image:Square.gif|left]] | *Max D.E. ~ 40% ± 1 order. *Power distributions favors odd orders. *Pi phase shift typical. *Classic binary grating. *T ≈ λ for transmission. *T ≈ λ/4 for reflection. |} === Blazed, sawtooth === {| |[[Image:Blazed.gif|left]] | *Max D.E ~ 98% *Reflection Case: **λ = 2 d sin a **T = λ/2 ± 10% *Transmission Case: **λ = d sin b **a ≈ 2b **T = λ/(n-1) ± 10% **Surface shadows reduce D.E. by <math>\textstyle \frac{\lambda^2}{n d^2}</math> **Wavelength changes reduce D.E. by <math>\textstyle \left(\frac{\pi\Delta\lambda}{b\lambda}\right)^2</math> |} == Holographic Deflectors (hologons) == {| |[[Image:Scan.gif|left]]<br> | *N = θD/(1.4λ) *N = number of resolvable spots *θ = full scan angle in radians *D = beam diameter in microns *λ = wavelength *Φ = wedge angle of glass *Special case of linear scan and near wobble invariance a ~ b ~ 45° max straight scan angle ~ 36° *Dynamic wobble <math>\scriptstyle \simeq \Delta\Omega/128</math> *Wedge wobble = (n-1)Φ *Scan angle multiplier = 1.4 @ 90° cross scan angle |} '''''Last modified on 9/29/97''''' [[Category:Rallison]] e522b71c022ab5f7ffe48ecb9eb50c6e312b370a 0 828 1893 1695 2013-05-12T19:10:08Z Jsfisher 1 wikitext text/x-wiki ==== Diffractive Optics Family ==== [[Image:Doptics.gif|center]] ==== What can you do with a wavefront? ==== {| cellspacing="5" |- valign="top" | [[Image:whatdo1.gif]] | [[Image:whatdo2.gif]] |} *Diffractive elements can be single-order or multi-order *Patterning resolution x Area (SBWP) is a measure of absolute design freedom *Phase encoding techniques provide the effective design freedom *Very large SBWP can be made by combining holographic recording with computed DOEs ==== Diffractive Optical Element Basic Functions ==== [[Image:does.gif|enter]] ==== Application Examples ==== *Beam-combiners for display systems *Laser scanners *Low noise and high performance diffraction gratings *Asphere testing elements *Spectral notch filters *Holographic laser optical heads *Optical interconnections in microelectronics *Wavefront sampling *Wavefront transformation-diffusers *Solar concentrations *Wavelength multiplexers/demultiplexers *Various unique laser optical elements ==== HUD with combiner laminated into the windshield for Volkswagon ==== [[Image:car.gif|center]] ==== Multi Order Super HOE Scanner ==== [[Image:suprhoe.gif|center]] ==== Potential Advantages Of Holographic Disk Scanners ==== *Simpler optical arrangement *Larger tolerances for wobble *Less air turbulence *Each facet can have a different focal length *Lower production cost per unit *Scan angle is independent of the number of facets ==== Aberration-Corrected HOE Grating For Spectrometer ==== [[Image:abrcorfs.gif|center]] ==== Interferometric Testing With A Computer-Generated Hologram ==== [[Image:comgenho.gif|center]] ==== Spectral Filters ==== [[Image:spctfltr.gif|center]] '''Advantages of Holographic Spectral Filters''' *Easy fabrication of large filters *High efficiency *Parallel layering is not a constraint *Free from extranious passbands ==== Colour Combination/Colour Separation ==== [[Image:colour.gif|center]] ==== Three Beam Optical Pickup For Compact Audio Disk Player ==== [[Image:cdplayer.gif|center]] ==== Optical Interconnections in Microelectronics ==== [[Image:opintmcr.gif|center]] ==== Fiber Optic Couplers ==== [[Image:fiberopc.gif|center]] ==== Wavefront Sampling of High Power Laser ==== [[Image:hipowlsr.gif|center]] ==== Wavefront Transformation System ==== [[Image:wavetran.gif|center]] ==== Faceted HOEs ==== [[Image:faceted.gif|center]] ==== Directional Diffusers ==== [[Image:dirdiff.gif|center]] ==== Solar Applications ==== [[Image:solarapp.gif|center]] ==== Wavelength Multiplexing/Demultiplexing ==== [[Image:wavelngt.gif|center]] ==== The Basic Optical Processor ==== [[Image:basoppro.gif|center]] ==== Anti-Reflective Structures ==== [[Image:antiref.gif|center]] *As the grating period gets smaller, the diffraction angles increase *Ultimately, gratings have only zero order transmitted and zero order reflected *Tailoring duty cycle and etch depth one can control the power in these two remaining orders *This is the same as an impedance match in electricity and magnetism ==== Concept For Holographic Night Goggles ==== [[Image:niteggls.gif|center]] ==== Holography ==== '''Advantages''' {| |- |[[Image:holo1.gif|center]] | *Images to a point with no aberrations *Aberration control possible *Highly dispersive *Optical power on a flat surface *Off-axis geometry *Can be transmissive or reflective *Narrowband response *Can be replicated |} '''Disadvantages''' {| |- |[[Image:holo2.gif|center]] | *High dispersion *Large aberration away from construction conditions *Efficient over small wavelength band *Limited design flexibility *Difficulty with control of holographic emulsions |} ==== Advantages of HOE Diffraction Gratings (HOEDGs) ==== {| border="1" |- ! <u>Property</u> ! <u>Classical Gratings</u> ! <u>HOEDGs</u> |- valign="top" | Efficiencies | 60 to 99% | 50 to 90% (surface relief only)<br>Efficiency at blaze is lower but the efficiency curve is flatter |- valign="top" | Ghosts | At best 10^-5 (usually 10^-2) of parent line | No ghosts at all |- valign="top" | Scattered light | At best 10^-5 to 10^-6 at 5Å of laser line in visible | At best 10^-6 to 10^-8 at 5Å of laser line in visible |- valign="top" | Size | In general standard sizes are limited to 8x8" | Up to Φ 17", but can be larger |- valign="top" | Number of grooves | Maximum 3600 lines/mm (There are rare exceptions.)<br>Scattered light increases drastically with density | Up to 6000 lines/mm<br> No increases of scatter with groove density |- valign="top" | Optical power | No | Yes<br>Volume HOEs can diffract 99% @ Bragg angle and center λ. |} ==== Single Element Dispersions Showing Hybrid Achromat Possibilities ==== [[Image:sngledis.gif|center]] ==== Comparisons of Fabrication Methods Of Diffractive Optics ==== {| border="1" |- ! <br> ! Diamond Turning ! Direct-Write ! Holographic or Photo-Lithography ! Embossing ! Injection Molding |- ! Practical production volumes | 10⁰ ~ 10² | 10⁰ ~ 10² | 10⁰ ~ 10⁵ | 10³ ~ 10⁵ | 10³ ~ 10⁷ |- ! Initial tooling costs | low-moderate | low | moderate-high | low-moderate | high |- ! Precision | low-moderate | good-excellent | excellent | moderate | moderate |- ! Materials | metals, plastics | glasses, semiconductors | glasses, semiconductors | plastics | plastics |- ! Volume production costs | high | high | low-moderate | low | low |} ==== Direct Laser Writing ==== [[Image:dir.gif|center]] *Spot sizes ~1 - 5um *Tightly Focuses, modulated He-Cd or Argon-ion laser scanned across photresists surface *Up to 256 phase levels *Serial Process *Difficult to accurately transfer structure into substrate *Direct ablation of polyimide layer on substrate using an excimer laser is also possible *Pattern can be transferred to a VHOE by processing in a 4f optical processor. ==== Photoresist Processes For Lithography ==== [[Image:photo.gif|center]] ==== Spin Coating Photoresist ==== [[Image:spincoat.gif|center]] ==== Replication Methods ==== [[Image:repmeth.gif|center]] ==== 3 Step Conversion of Volume HOE to Surface Blazed HOE ==== [[Image:3step.gif|center]] ==== Laboratory Optical Test Apparatus ==== [[Image:labtest.gif|center]] ==== Rotating Slit Scanners (Beam Scan) ==== [[Image:rotslit.gif|center]] *Narrow, rotating slit is scanned through pattern *Measure irradiance profiles with ~micron lateral precision *Slit widths down to 1 um *Scan areas over 10 mm are possible *Measurement of both near and far-field diffraction patterns *Both 1-D and 2-D scans can be performed ==== Scatterometer ==== [[Image:scattm.gif|center]] *Measures irradiance patterns from DOE's by scanning a detector and pinhole *Scanning and data acquisition is computer controlled (LabView™ software) *Precision depends on pinhole size and step-size of motorized stage *Slow process *Can be difficult to align scan axis ==== Ronchi Rule -- Gaussian Spot Sise Measurement. (Lee Dickson) ==== [[Image:ronchi.gif|center]] *do = 1/e² spot *w = bar width *K = pmin/pmax *do/w = 2.2K + 1 Side view of ruling in beam ==== An Electromagnetic Shutter From A D'Arsenual ==== [[Image:shutter.gif|center]]<br>Shutter is silent and can easily be configured to close after accumulating a preset energy per unit area. ==== Hologram Exposure -- Single-Beam With Nonconformal Mirror ==== [[Image:nncnmirr.gif|center]]<br> Introduced by Yuri M. Denisyuk in early 1960s. ==== Single Beam Frame Using All Second Surface Mirror Without Ghosts (from Saxby) ==== [[Image:brewster.gif|center]] ==== Lloyd's Mirror ==== [[Image:loydsmir.gif|center]] ==== Gravity plateholder (after Abramson⁹ For NDT Apps ==== [[Image:gravity.gif|center]] ==== Film Holder With Xylene Well (after Benton, 1960s) ==== [[Image:filmhold.gif|center]] ==== Full-Aperature Transfer Hologram ==== [[Image:focusopt.gif|center]] ==== Rainbow Hologram (Benton, 1965) ==== [[Image:rainbowh.gif|center]] ==== Holographic Stereogram, after DeBitetto, 1968-69 ==== [[Image:debiteto.gif|center]] ==== 35 mm Holocamera by David Rowley ==== [[Image:holocam.gif|center]] ==== Contact Printing (copying) Of Transmission Or Reflection Holograms ==== [[Image:ctcprnt.gif|center]] ==== Secondary Holograms Formed By Scattered Light In A Construction Beam ==== [[Image:secndary.gif|center]]<br> Any stray or scattered light can combine with a construction beam to form secondary transmission and reflections holograms ==== Secondary Holograms Formed By Surface Reflections ==== [[Image:surfrefl.gif|center]]<br> The reflection portion of construction wave 1 combines with construction wave 2 to form a Transmission hologram ==== Prevention Of Secondary Holograms Formed By Surface Reflections ==== [[Image:orevsd.gif|center]] ==== Spurious (secondary) Holograms ==== [[Image:spurius.gif|center]] *Desired hologram: **Reflection hologram AB *Spurious holograms: **Reflection hologram AA1 **Reflection hologram BB1 **Reflection hologram A1B1 **Transmission hologram AB1 **Transmission hologram A1B ==== Prevention of Secondary Holograms ==== [[Image:prvntsho.gif|center]] ==== Michaelson Interferometer, Table Check, Fringelocker Check ==== [[Image:micinter.gif|center]] ==== Unique Characteristics Of HOEs ==== *Perfect imaging between two points for a single wavelength *Useful in unusual (I.E., not in-line) geometries *Shape independent (I.E., flat surfaces can have optical power) *Extremely dispersive (effice v-number of -3.45) *Angle selection *Wavelength selective *Multiple functions *Multiple elements in the same aperture *Compact and light weight *Relatively inexpensive - low cost "photographic" replication ==== Requirements on Construction Optical System ==== *Hight quality optical elements *Minimize multiple reflections between surfaces of construction optics and hologram substrate *Scattered light should be prevented from falling on hologram plate *Mechanical and thermal stability during exposure *Proper coherence length *Polarization of two recording beams should be maintained properly *Active fringe stabilization system for long exposures ==== Form Birefringence ==== [[Image:birefrin.gif|center]] *Subwavelength gratings behave somewhat like biaxial crystals *As the period gets small relative to the wavelength, we can calculate an equivalent dielectric constant or index of refraction (n) ''Last modified on 7/21/99'' [[Category:Rallison]] 74613e0af7814bb37020c81f6aa71d145ba19f24 0 832 1894 1715 2013-05-12T21:12:24Z Jsfisher 1 wikitext text/x-wiki [[Media:Holotool.exe.remove|Holotool.EXE]] is a self extracting program that contains four DOS executables and three pcx drawings totaling just 115 kbytes when expanded by running Holotool. (You will need to rename the download to remove the extraneous ".remove" file suffix.) It is probably best to run it in it's own directory, so identifying the individual programs is easy. The programs included are as follows: '''EXPAND2.EXE''' is a menu driven program that asks you for the playback and construction wavelengths, the playback and construction bulk index of refraction of the recording media, the external angles for playing back either a transmission or reflection HOE or hologram and the thickness change multiplier expected from your film. The output is the internal Bragg angle, the spatial frequency and the internal and external construction angles for both before and after expansion or shrinkage of the film. The program toggles through remembering what you did and allowing changes to be made to quickly try out a lot of configurations to find out what will probably work and what will not. '''TIR2.EXE''' is just like Expand2 except that the second angle it asks for is the internal playback angle, which allows you to design total internal reflection (TIR) HOEs or edge lit holograms. The output includes a prompting for a best angle prism to index match to the film substrate and allows you to input any angle prism you may have and then outputs an angle for the non prism side and one for the ray entering the prism if a reflection geometry results or two ray angles measured off the normal to the prism in the case of a transmission outcome. TIR fringes hover around 45 degrees of Brag tilt and are especially hard to make correctly so this is the most valuable of the utilities I use myself and the newest of the three programs. '''TIR2.PYW''' (not part of the holotools package) is a graphical version of TIR2, written in [http://www.python.org/ wxPython], for Windows 95/98/NT and UNIX/Linux. To use this program, you will need to download the [[Media:tir2.pyw.remove | tir2.pyw]] program file and the [http://www.python.org/download/download_windows.html Python Interpreter] and the [http://www.wxpython.org/download.php wxPython toolkit]. (You will need to rename the download to remove the ".remove" suffix.) After installing the wxPython software package, the TIR2.PYW program file will be executable. To learn more about wxPython, go to the [http://wxpython.org/ wxPython home page]. ''Note:'' tir2.pyw is a work in progress. Please send all suggestions or bug reports to rdr@ralcon.com. '''CHIRP.EXE''' is an older Fortran program that models holographic or dielectric mirror stacks using a quarter wave model or Kogelnic's approximation, you get to choose. The inputs are bulk index, center wavelength, film thickness, average expected index modulation, absorption of the holographic film during exposure in percent (gradient), percent change in fringe spacing as a function of depth (chirp) and wavelength range to scan symmetrically around the center wavelength. The outputs are first a plot of index modulation as a function of depth then a plot of density versus wavelength and if you choose to save the file when prompted you can retrieve it with CHIRCALL.EXE and display and print an amplitude reflection plot to use to match up with a spectrophotometer output of a real mirror. This program is useful for measuring the index modulation of a film when things are not linear or uniform as is true for most recording media. There are three GIF files, [[Media:expand2.gif | EXPAND.GIF]], [[Media:tir2.gif | TIR2.GIF]] and [[Media:nchirp.gif | NCHIRP.GIF]] that give sign conventions and further instructions for using their respective namesakes. These are easily read and printed from Paintbrush and many other programs including word processors. For those that prefer to customize their software, the source code for the two C programs is also available by email. [[Category:Rallison]] 31e7b418215d184ac0a05eaa3d0fe44e32d03b5b 1895 1894 2013-05-12T21:16:06Z Jsfisher 1 wikitext text/x-wiki [[Media:Holotool.exeremove|Holotool.EXE]] is a self extracting program that contains four DOS executables and three pcx drawings totaling just 115 kbytes when expanded by running Holotool. (You will need to rename the download to strip the extraneous "remove" from file suffix.) It is probably best to run it in it's own directory, so identifying the individual programs is easy. The programs included are as follows: '''EXPAND2.EXE''' is a menu driven program that asks you for the playback and construction wavelengths, the playback and construction bulk index of refraction of the recording media, the external angles for playing back either a transmission or reflection HOE or hologram and the thickness change multiplier expected from your film. The output is the internal Bragg angle, the spatial frequency and the internal and external construction angles for both before and after expansion or shrinkage of the film. The program toggles through remembering what you did and allowing changes to be made to quickly try out a lot of configurations to find out what will probably work and what will not. '''TIR2.EXE''' is just like Expand2 except that the second angle it asks for is the internal playback angle, which allows you to design total internal reflection (TIR) HOEs or edge lit holograms. The output includes a prompting for a best angle prism to index match to the film substrate and allows you to input any angle prism you may have and then outputs an angle for the non prism side and one for the ray entering the prism if a reflection geometry results or two ray angles measured off the normal to the prism in the case of a transmission outcome. TIR fringes hover around 45 degrees of Brag tilt and are especially hard to make correctly so this is the most valuable of the utilities I use myself and the newest of the three programs. '''TIR2.PYW''' (not part of the holotools package) is a graphical version of TIR2, written in [http://www.python.org/ wxPython], for Windows 95/98/NT and UNIX/Linux. To use this program, you will need to download the [[Media:tir2.pywremove | tir2.pyw]] program file and the [http://www.python.org/download/download_windows.html Python Interpreter] and the [http://www.wxpython.org/download.php wxPython toolkit]. (You will need to rename the download to strip the "remove" form the file suffix.) After installing the wxPython software package, the TIR2.PYW program file will be executable. To learn more about wxPython, go to the [http://wxpython.org/ wxPython home page]. ''Note:'' tir2.pyw is a work in progress. Please send all suggestions or bug reports to rdr@ralcon.com. '''CHIRP.EXE''' is an older Fortran program that models holographic or dielectric mirror stacks using a quarter wave model or Kogelnic's approximation, you get to choose. The inputs are bulk index, center wavelength, film thickness, average expected index modulation, absorption of the holographic film during exposure in percent (gradient), percent change in fringe spacing as a function of depth (chirp) and wavelength range to scan symmetrically around the center wavelength. The outputs are first a plot of index modulation as a function of depth then a plot of density versus wavelength and if you choose to save the file when prompted you can retrieve it with CHIRCALL.EXE and display and print an amplitude reflection plot to use to match up with a spectrophotometer output of a real mirror. This program is useful for measuring the index modulation of a film when things are not linear or uniform as is true for most recording media. There are three GIF files, [[Media:expand2.gif | EXPAND.GIF]], [[Media:tir2.gif | TIR2.GIF]] and [[Media:nchirp.gif | NCHIRP.GIF]] that give sign conventions and further instructions for using their respective namesakes. These are easily read and printed from Paintbrush and many other programs including word processors. For those that prefer to customize their software, the source code for the two C programs is also available by email. [[Category:Rallison]] 494d3c766907d7dcb109a3fa9e30dcac6b601383 1896 1895 2013-05-12T21:20:36Z Jsfisher 1 wikitext text/x-wiki [[Media:Holotool.zip|Holotool.exe]] is a self extracting program that contains four DOS executables and three pcx drawings totaling just 115 kbytes when expanded by running Holotool. It is probably best to run it in it's own directory, so identifying the individual programs is easy. The programs included are as follows: '''EXPAND2.EXE''' is a menu driven program that asks you for the playback and construction wavelengths, the playback and construction bulk index of refraction of the recording media, the external angles for playing back either a transmission or reflection HOE or hologram and the thickness change multiplier expected from your film. The output is the internal Bragg angle, the spatial frequency and the internal and external construction angles for both before and after expansion or shrinkage of the film. The program toggles through remembering what you did and allowing changes to be made to quickly try out a lot of configurations to find out what will probably work and what will not. '''TIR2.EXE''' is just like Expand2 except that the second angle it asks for is the internal playback angle, which allows you to design total internal reflection (TIR) HOEs or edge lit holograms. The output includes a prompting for a best angle prism to index match to the film substrate and allows you to input any angle prism you may have and then outputs an angle for the non prism side and one for the ray entering the prism if a reflection geometry results or two ray angles measured off the normal to the prism in the case of a transmission outcome. TIR fringes hover around 45 degrees of Brag tilt and are especially hard to make correctly so this is the most valuable of the utilities I use myself and the newest of the three programs. '''TIR2.PYW''' (not part of the holotools package) is a graphical version of TIR2, written in [http://www.python.org/ wxPython], for Windows 95/98/NT and UNIX/Linux. To use this program, you will need to download the [[Media:Holotool.zip | tir2.pyw]] program file and the [http://www.python.org/download/download_windows.html Python Interpreter] and the [http://www.wxpython.org/download.php wxPython toolkit]. After installing the wxPython software package, the TIR2.PYW program file will be executable. To learn more about wxPython, go to the [http://wxpython.org/ wxPython home page]. ''Note:'' tir2.pyw is a work in progress. Please send all suggestions or bug reports to rdr@ralcon.com. '''CHIRP.EXE''' is an older Fortran program that models holographic or dielectric mirror stacks using a quarter wave model or Kogelnic's approximation, you get to choose. The inputs are bulk index, center wavelength, film thickness, average expected index modulation, absorption of the holographic film during exposure in percent (gradient), percent change in fringe spacing as a function of depth (chirp) and wavelength range to scan symmetrically around the center wavelength. The outputs are first a plot of index modulation as a function of depth then a plot of density versus wavelength and if you choose to save the file when prompted you can retrieve it with CHIRCALL.EXE and display and print an amplitude reflection plot to use to match up with a spectrophotometer output of a real mirror. This program is useful for measuring the index modulation of a film when things are not linear or uniform as is true for most recording media. There are three GIF files, [[Media:expand2.gif | EXPAND.GIF]], [[Media:tir2.gif | TIR2.GIF]] and [[Media:nchirp.gif | NCHIRP.GIF]] that give sign conventions and further instructions for using their respective namesakes. These are easily read and printed from Paintbrush and many other programs including word processors. For those that prefer to customize their software, the source code for the two C programs is also available by email. [[Category:Rallison]] cd0a16e094cc6e00a83e5f6e7df11a9cc7a8625e 6 867 1897 2013-05-12T21:20:51Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 868 1898 2013-05-13T02:48:54Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 869 1899 2013-05-13T02:54:29Z Jsfisher 1 Created page with "===People=== <gallery> File:AStephens.jpg | Somebody File:BCole.jpg | Somebody File:Benton.jpg | Somebody File:Colink.jpg | Colin Kaminski File:Cross.jpg | Someb..." wikitext text/x-wiki ===People=== <gallery> File:AStephens.jpg | Somebody File:BCole.jpg | Somebody File:Benton.jpg | Somebody File:Colink.jpg | Colin Kaminski File:Cross.jpg | Somebody File:DBattin.jpg | Dave Battin File:Ed_Wesly.jpg | Ed Wesly File:FDeFreitas 2.jpg | Frank DeFreitas File:FDeFreitas.jpg | Frank DeFreitas File:Gabor.gif | Gabor, inventor of holography File:GFavalora.jpg | Somebody File:GLippmann.jpg | Lippmann File:HSilver.jpg | Somebody File:JBlyth.jpg | Jeff Blyth File:Jross.jpg | Somebody File:JUpatnieks.jpg | Somebody File:KBazargan.jpg | Somebody File:Lcross.jpg | Somebody File:Mbenyon.gif | Somebody File:MichaelHDag.jpg | Somebody File:Mmueller.jpg | Somebody File:Pchristie.jpg | Somebody File:Rdr.gif | Richard D. Rallison File:RDRJack84.jpg | Somebody File:RDRJerry83.jpg | Somebody File:RDRLloyd.jpg | Somebody File:RDRMikef.jpg | Somebody File:RDRPosyoffice76.jpg | Somebody File:RDRRdraust.jpg | Somebody File:RDRRick.jpg | Somebody File:RDRSpike.jpg | Somebody File:RDRUri.jpg | Uri Denisyuk File:RLakes.jpg | Somebody File:SVorobyov.jpg | Somebody File:SZharkiy.jpg | Somebody File:YDenisyuk2.jpg | Uri Denisyuk </gallery> 8b4613c152618a4901acb8596678338406a6dd27 1900 1899 2013-05-13T04:13:47Z Jsfisher 1 wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.jpg | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Keveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:Berkhout.jpg | [[Rudie Berkhout]] File:Bhelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:CardinSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | Somebody File:BCole.jpg | Somebody File:Crenshaw | [[Melissa Crenshaw]] File:Cross.jpg | [[Loyd Cross]] File:Lcross.jpg | [[Loyd Cross]] File:MichaelHDag.jpg | Somebody File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavolora.jpg | [[Gregg E. Favalora]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:Harrison.jpg | [[Michael Harrison]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:GLippmann.jpg | Lippmann File:Kaufmna.jpg | [[John Kaufman]] File:Lakes.jpg | [[Roderic Lakes]] File:Leith.jpg | [[Emmett Leith]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:RDR.gif | [[Richard Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Rdr.gif | Richard D. Rallison File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] file:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | Somebody File:RDRJerry83.jpg | Somebody File:RDRLloyd.jpg | Somebody File:RLakes.jpg | Somebody File:RDRMikef.jpg | Somebody File:RDRPosyoffice76.jpg | Somebody File:RDRRdraust.jpg | Somebody File:RDRRick.jpg | Somebody File:RDRSpike.jpg | Somebody File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> f1284a1c8851373d803d40e4eea23b9f823b9b9d 1901 1900 2013-05-13T04:15:37Z Jsfisher 1 wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.jpg | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Keveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:Berkhout.jpg | [[Rudie Berkhout]] File:Bhelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:CardinSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | Somebody File:BCole.jpg | Somebody File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Loyd Cross]] File:MichaelHDag.jpg | Somebody File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavolora.jpg | [[Gregg E. Favalora]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:Harrison.jpg | [[Michael Harrison]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:GLippmann.jpg | Lippmann File:Kaufmna.jpg | [[John Kaufman]] File:Lakes.jpg | [[Roderic Lakes]] File:Leith.jpg | [[Emmett Leith]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:RDR.gif | [[Richard Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Rdr.gif | Richard D. Rallison File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] file:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | Somebody File:RDRJerry83.jpg | Somebody File:RDRLloyd.jpg | Somebody File:RLakes.jpg | Somebody File:RDRMikef.jpg | Somebody File:RDRPosyoffice76.jpg | Somebody File:RDRRdraust.jpg | Somebody File:RDRRick.jpg | Somebody File:RDRSpike.jpg | Somebody File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> 5d8e4ab725af5a0d5660c3dc6d9676d2141ec2d8 1902 1901 2013-05-13T04:18:54Z Jsfisher 1 wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.jpg | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Keveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:Berkhout.jpg | [[Rudie Berkhout]] File:Bhelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:CardinSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | Somebody File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Loyd Cross]] File:MichaelHDag.jpg | Somebody File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavolora.jpg | [[Gregg E. Favalora]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:Harrison.jpg | [[Michael Harrison]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:GLippmann.jpg | Lippmann File:Kaufmna.jpg | [[John Kaufman]] File:Lakes.jpg | [[Roderic Lakes]] File:Leith.jpg | [[Emmett Leith]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:RDR.gif | [[Richard Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Rdr.gif | Richard D. Rallison File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] file:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | Somebody File:RDRJerry83.jpg | Somebody File:RDRLloyd.jpg | Somebody File:RLakes.jpg | Somebody File:RDRMikef.jpg | Somebody File:RDRPosyoffice76.jpg | Somebody File:RDRRdraust.jpg | Somebody File:RDRRick.jpg | Somebody File:RDRSpike.jpg | Somebody File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> 21a60bf69f48722e75b349d8086e74f751d5d21f 0 820 1908 1645 2013-05-14T01:48:15Z Jsfisher 1 wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. The are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. Epoxy is normal sealant. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref>. If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref>. These two images were taken from source <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref>. [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref>. Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref>. Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom <ref name="r13" /> <ref name="r14" />. This image was taken from source <ref name="r16" />. [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref>. Research is needed using vitamin C with CrVI <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref>. ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref>. During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram <ref name="r15" />. The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://en.wikipedia.org/wiki/Collagen # http://www.britannica.com/eb/article-72553/protein # http://www.lsbu.ac.uk/water/hygel.html # http://www.stanford.edu/~spark7/ # http://en.wikipedia.org/wiki/Gelatin # http://www.lsbu.ac.uk/water/hygel.html # http://albumen.stanford.edu/library/c20/kozlov1983.html # http://www.greatlakesgelatin.com/gelatin%20information.htm # http://www.cdc.gov/niosh/topics/hexchrom/ # http://en.wikipedia.org/wiki/Hexavalent_chromium # http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/ # http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf # http://www.gelatin-gmia.com/index.htm # [[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]] # http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html # http://sandwalk.blogspot.com/2007/02/collagen.html == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. [[Category:DCG]] [[Category:Beginner]] a7c6ebc03187baa41f31f4b9b1a61e183b75e27d 1910 1908 2013-05-14T01:54:52Z Jsfisher 1 wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. The are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. Epoxy is normal sealant. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://en.wikipedia.org/wiki/Collagen # http://www.britannica.com/eb/article-72553/protein # http://www.lsbu.ac.uk/water/hygel.html # http://www.stanford.edu/~spark7/ # http://en.wikipedia.org/wiki/Gelatin # http://www.lsbu.ac.uk/water/hygel.html # http://albumen.stanford.edu/library/c20/kozlov1983.html # http://www.greatlakesgelatin.com/gelatin%20information.htm # http://www.cdc.gov/niosh/topics/hexchrom/ # http://en.wikipedia.org/wiki/Hexavalent_chromium # http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/ # http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf # http://www.gelatin-gmia.com/index.htm # [[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]] # http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html # http://sandwalk.blogspot.com/2007/02/collagen.html == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. [[Category:DCG]] [[Category:Beginner]] 532490e2561b0a38c94aeed62e19498c8f1843d5 1914 1910 2013-05-14T02:08:33Z Jsfisher 1 /* The Mechanics of Gelatin in the Dichromated Holography Process */ wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. The are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. Epoxy is normal sealant. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> {| |- | [[Image:collagen1.gif]] |- | Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) |} {| |- | [[Image:collagen2.gif]] |- | Collagen molecules line-up to form a fibril in "quarter staggered" array. |} ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> {| |- |[[Image:gelatin1.gif]] |- | Denaturation of collagen |} ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. [[Category:DCG]] [[Category:Beginner]] 62a552ea50e941e77ddb96c10cb1b892128ce95f 6 295 1911 484 2013-05-14T01:59:55Z Jsfisher 1 Jsfisher uploaded &quot;[[File:Collagen1.gif]]&quot; wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 296 1912 486 2013-05-14T02:00:11Z Jsfisher 1 Jsfisher uploaded &quot;[[File:Collagen2.gif]]&quot; wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 306 1913 568 2013-05-14T02:00:32Z Jsfisher 1 Jsfisher uploaded &quot;[[File:Gelatin1.gif]]&quot; wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 820 1915 1914 2013-05-14T02:09:59Z Jsfisher 1 wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. The are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. Epoxy is normal sealant. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> {| |- | [[Image:collagen1.gif]] |- | Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) |} {| |- | [[Image:collagen2.gif]] |- | Collagen molecules line-up to form a fibril in "quarter staggered" array. |} ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> {| |- |[[Image:gelatin1.gif]] |- | Denaturation of collagen |} ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html [[Category:DCG]] [[Category:Beginner]] 69d93306c0ec26962ae141e609413b824f0a2f3f 1916 1915 2013-05-14T02:13:22Z Jsfisher 1 wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. The are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. Epoxy is normal sealant. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html [[Category:DCG]] [[Category:Beginner]] 2399e7f4bacd13b479a2a4216f90f37e63211d94 0 869 1917 1902 2013-05-14T02:43:18Z Jsfisher 1 /* People */ wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.jpg | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Kaveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:Berkhout.jpg | [[Rudie Berkhout]] File:Bhelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:CardinSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | [[Bernard Cole]] File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Loyd Cross]] File:MichaelHDag.jpg | Somebody "Michael H Dag" File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavolora.jpg | [[Gregg E. Favalora]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:Harrison.jpg | [[Michael Harrison]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:GLippmann.jpg | Jonas Ferdinand [[Gabriel Lippmann]] File:Kaufmna.jpg | [[John Kaufman]] File:Lakes.jpg | [[Roderic Lakes]] File:Leith.jpg | [[Emmett Leith]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody M Mueller File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:RDR.gif | [[Richard Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Rdr.gif | Richard D. Rallison File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody H Silver File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] file:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | Somebody RDRJack84 File:RDRJerry83.jpg | Somebody RDRJerry83 File:RDRLloyd.jpg | Somebody RDRLloyd File:RLakes.jpg | Somebody R Lakes File:RDRMikef.jpg | Somebody RDRMikef File:RDRPosyoffice76.jpg | Somebody RDRPosyoffice76 File:RDRRdraust.jpg | Somebody RDRRdraust File:RDRRick.jpg | Somebody RDRRick File:RDRSpike.jpg | Somebody RDRSpike File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> 005d139ab40c440b0fcced94a0ef47363acbc9f4 1921 1917 2013-05-14T23:10:44Z Jsfisher 1 wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.jpg | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Kaveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:Berkhout.jpg | [[Rudie Berkhout]] File:Bhelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:CardinSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | [[Bernard Cole]] File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Loyd Cross]] File:MichaelHDag.jpg | Somebody "Michael H Dag" File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavolora.jpg | [[Gregg E. Favalora]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:Harrison.jpg | [[Michael Harrison]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:GLippmann.jpg | Jonas Ferdinand [[Gabriel Lippmann]] File:Kaufmna.jpg | [[John Kaufman]] File:Lakes.jpg | [[Roderic Lakes]] File:Leith.jpg | [[Emmett Leith]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody M Mueller File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:FB_Rallison.jpg | [[Rallison, Richard | Richard Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Rdr.gif | Richard D. Rallison File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody H Silver File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] file:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | Somebody RDRJack84 File:RDRJerry83.jpg | Somebody RDRJerry83 File:RDRLloyd.jpg | Somebody RDRLloyd File:RLakes.jpg | Somebody R Lakes File:RDRMikef.jpg | Somebody RDRMikef File:RDRPosyoffice76.jpg | Somebody RDRPosyoffice76 File:RDRRdraust.jpg | Somebody RDRRdraust File:RDRRick.jpg | Somebody RDRRick File:RDRSpike.jpg | Somebody RDRSpike File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> f15c0f6032d7f6a87a31476a018f0e4e1c9ffbfb 1922 1921 2013-05-14T23:13:45Z Jsfisher 1 wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.jpg | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Kaveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:Berkhout.jpg | [[Rudie Berkhout]] File:Bhelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:CardinSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | [[Bernard Cole]] File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Loyd Cross]] File:MichaelHDag.jpg | Somebody "Michael H Dag" File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavolora.jpg | [[Gregg E. Favalora]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:Harrison.jpg | [[Michael Harrison]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:GLippmann.jpg | Jonas Ferdinand [[Gabriel Lippmann]] File:Kaufmna.jpg | [[John Kaufman]] File:Lakes.jpg | [[Roderic Lakes]] File:Leith.jpg | [[Emmett Leith]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody M Mueller File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:FB_Rallison.jpg | [[Rallison, Richard | Richard D. Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody H Silver File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] file:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | Somebody RDRJack84 File:RDRJerry83.jpg | Somebody RDRJerry83 File:RDRLloyd.jpg | Somebody RDRLloyd File:RLakes.jpg | Somebody R Lakes File:RDRMikef.jpg | Somebody RDRMikef File:RDRPosyoffice76.jpg | Somebody RDRPosyoffice76 File:RDRRdraust.jpg | Somebody RDRRdraust File:RDRRick.jpg | Somebody RDRRick File:RDRSpike.jpg | Somebody RDRSpike File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> 63a7cf3e8577edb7cb4c91e9f93a6d6c249d5edc 1927 1922 2013-05-14T23:29:59Z Jsfisher 1 wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.gif | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Kaveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:RudieBerkhout.jpg | [[Rudie Berkhout]] File:Bhelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:CardinSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | [[Bernard Cole]] File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Loyd Cross]] File:MichaelHDag.jpg | Somebody "Michael H Dag" File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavolora.jpg | [[Gregg E. Favalora]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:Harrison.jpg | [[Michael Harrison]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:GLippmann.jpg | Jonas Ferdinand [[Gabriel Lippmann]] File:Kaufmna.jpg | [[John Kaufman]] File:Lakes.jpg | [[Roderic Lakes]] File:Leith.jpg | [[Emmett Leith]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody M Mueller File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:FB_Rallison.jpg | [[Rallison, Richard | Richard D. Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody H Silver File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] file:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | Somebody RDRJack84 File:RDRJerry83.jpg | Somebody RDRJerry83 File:RDRLloyd.jpg | Somebody RDRLloyd File:RLakes.jpg | Somebody R Lakes File:RDRMikef.jpg | Somebody RDRMikef File:RDRPosyoffice76.jpg | Somebody RDRPosyoffice76 File:RDRRdraust.jpg | Somebody RDRRdraust File:RDRRick.jpg | Somebody RDRRick File:RDRSpike.jpg | Somebody RDRSpike File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> 84a9ca492798aabc990fb96984e046eee960a761 1939 1927 2013-05-15T01:36:47Z Jsfisher 1 wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.gif | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Kaveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:RudieBerkhout.jpg | [[Rudie Berkhout]] File:Bhelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:CardinSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | [[Bernard Cole]] File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Cross, Lloyd | Lloyd Cross]] File:MichaelHDag.jpg | Somebody "Michael H Dag" File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavolora.jpg | [[Gregg E. Favalora]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:Harrison.jpg | [[Michael Harrison]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:GLippmann.jpg | Jonas Ferdinand [[Gabriel Lippmann]] File:Kaufmna.jpg | [[John Kaufman]] File:Lakes.jpg | [[Roderic Lakes]] File:Leith.jpg | [[Emmett Leith]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody M Mueller File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:FB_Rallison.jpg | [[Rallison, Richard | Richard D. Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody H Silver File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] file:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | Somebody RDRJack84 File:RDRJerry83.jpg | Somebody RDRJerry83 File:RDRLloyd.jpg | Somebody RDRLloyd File:RLakes.jpg | Somebody R Lakes File:RDRMikef.jpg | Somebody RDRMikef File:RDRPosyoffice76.jpg | Somebody RDRPosyoffice76 File:RDRRdraust.jpg | Somebody RDRRdraust File:RDRRick.jpg | Somebody RDRRick File:RDRSpike.jpg | Somebody RDRSpike File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> 2bab36475502800837bcd33f59d87eb59462f957 0 178 1918 1601 2013-05-14T22:52:41Z Jsfisher 1 wikitext text/x-wiki The backgrounds of holographers are extremely varied, as can be seen below. Without these people's tireless efforts, holography would have remained a mere laboratory curiosity, rarely to be seen elsewhere. As a result of their work, holographic techniques are more and more frequently used in science, technology, medicine, measurement and art. With the advent of lower cost lasers and recording materials, and also due to the work of the dedicated holographic popularizers among those listed below, there is a small but growing international community of amateur holographers, and it is not uncommon to have hands-on holography courses presented in elementary schools. This project is designed to collect in one place biographical info on all of the people who have made holography possible. Please feel free to post your biographies here. If you know a name but don't know the details, just add the name and we will work on getting a biography. <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> *[[Dave Battin]] *[[Paul D. Barefoot]] *[[Kaveh Bazargan]] *[[Margaret Benyon]] *[[Steve Benton]] *[[Rudie Berkhout]] *[[Hans Bjelkhagen]] *[[Jeff Blyth]] *[[Patrick Boyd]] *[[Pam Brasier]] *[[Harriet Casdin-Silver]] *[[Greg Cherry]] *[[Melissa Crenshaw]] *[[Loyd Cross]] *[[Salvador Dali]] *[[Rebecca Deem]] *[[Frank DeFreitas]] *[[Yuri Denisyuk]] *[[Georges Dyens]] *[[Phil Edelbrock]] *[[Gregg E. Favalora]] *[[Dennis Gabor]] *[[Yves Gentet]] *[[Andres Ghisays]] *[[Nancy J. Gorglione]] *[[Michael Harrison]] *[[Dr. Jeong]] T. J. *[[Frithioff Johansen]] *[[Pearl John]] *[[Colin Kaminski]] *[[John Kaufman]] *[[Roderic Lakes]] *[[Emmett Leith]] *[[Sharon McCormack]] *[[Mike Medora]] *[[Ronnie Michael]] *[[Lon Moore]] *[[Rob Munday]] *[[August Muth]] *[[Ikuo Nakamura]] *[[Anna Maria Nicholson]] *[[Caroline Palmer]] *[[Dinesh Padiyar]] *[[Joy Padiyar]] *[[John Pecora]] *[[Andrew Pepper]] *[[Hart Perry]] *[[Jerry Pethick]] *[[Nicholas Phillips]] *[[Greg Quinn]] * [[Rallison, Richard | Richard Rallison]] *[[Al Razutis]] *[[Jonathan Ross]] *[[Graham Saxby]] *[[Dan Schweitzer]] *[[Mark Segal]] *[[Walter Spierings]] *[[Anait Stephens]] *[[Fred Unterseher]] *[[Juris Upatnieks]] *[[Doris Vila]] *[[John Webster]] *[[Edward Wesly]] *[[Mieczyslaw Wolfke]] *[[Sergey Vorobyov]] *[[Sergey Zharkiy]] </div> e1249c69ebf1bb4ea4dee0e8f952dea63e993a67 1937 1918 2013-05-15T01:33:29Z Jsfisher 1 wikitext text/x-wiki The backgrounds of holographers are extremely varied, as can be seen below. Without these people's tireless efforts, holography would have remained a mere laboratory curiosity, rarely to be seen elsewhere. As a result of their work, holographic techniques are more and more frequently used in science, technology, medicine, measurement and art. With the advent of lower cost lasers and recording materials, and also due to the work of the dedicated holographic popularizers among those listed below, there is a small but growing international community of amateur holographers, and it is not uncommon to have hands-on holography courses presented in elementary schools. This project is designed to collect in one place biographical info on all of the people who have made holography possible. Please feel free to post your biographies here. If you know a name but don't know the details, just add the name and we will work on getting a biography. <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> *[[Dave Battin]] *[[Paul D. Barefoot]] *[[Kaveh Bazargan]] *[[Margaret Benyon]] *[[Steve Benton]] *[[Rudie Berkhout]] *[[Hans Bjelkhagen]] *[[Jeff Blyth]] *[[Patrick Boyd]] *[[Pam Brasier]] *[[Harriet Casdin-Silver]] *[[Greg Cherry]] *[[Melissa Crenshaw]] *[[Lloyd Cross | Cross, Lloyd]] *[[Salvador Dali]] *[[Rebecca Deem]] *[[Frank DeFreitas]] *[[Yuri Denisyuk]] *[[Georges Dyens]] *[[Phil Edelbrock]] *[[Gregg E. Favalora]] *[[Dennis Gabor]] *[[Yves Gentet]] *[[Andres Ghisays]] *[[Nancy J. Gorglione]] *[[Michael Harrison]] *[[Dr. Jeong]] T. J. *[[Frithioff Johansen]] *[[Pearl John]] *[[Colin Kaminski]] *[[John Kaufman]] *[[Roderic Lakes]] *[[Emmett Leith]] *[[Sharon McCormack]] *[[Mike Medora]] *[[Ronnie Michael]] *[[Lon Moore]] *[[Rob Munday]] *[[August Muth]] *[[Ikuo Nakamura]] *[[Anna Maria Nicholson]] *[[Caroline Palmer]] *[[Dinesh Padiyar]] *[[Joy Padiyar]] *[[John Pecora]] *[[Andrew Pepper]] *[[Hart Perry]] *[[Jerry Pethick]] *[[Nicholas Phillips]] *[[Greg Quinn]] * [[Rallison, Richard | Richard Rallison]] *[[Al Razutis]] *[[Jonathan Ross]] *[[Graham Saxby]] *[[Dan Schweitzer]] *[[Mark Segal]] *[[Walter Spierings]] *[[Anait Stephens]] *[[Fred Unterseher]] *[[Juris Upatnieks]] *[[Doris Vila]] *[[John Webster]] *[[Edward Wesly]] *[[Mieczyslaw Wolfke]] *[[Sergey Vorobyov]] *[[Sergey Zharkiy]] </div> 1aa4d0ff7922d44fed2e48ca8c59002ba44830ba 1938 1937 2013-05-15T01:34:18Z Jsfisher 1 wikitext text/x-wiki The backgrounds of holographers are extremely varied, as can be seen below. Without these people's tireless efforts, holography would have remained a mere laboratory curiosity, rarely to be seen elsewhere. As a result of their work, holographic techniques are more and more frequently used in science, technology, medicine, measurement and art. With the advent of lower cost lasers and recording materials, and also due to the work of the dedicated holographic popularizers among those listed below, there is a small but growing international community of amateur holographers, and it is not uncommon to have hands-on holography courses presented in elementary schools. This project is designed to collect in one place biographical info on all of the people who have made holography possible. Please feel free to post your biographies here. If you know a name but don't know the details, just add the name and we will work on getting a biography. <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> *[[Dave Battin]] *[[Paul D. Barefoot]] *[[Kaveh Bazargan]] *[[Margaret Benyon]] *[[Steve Benton]] *[[Rudie Berkhout]] *[[Hans Bjelkhagen]] *[[Jeff Blyth]] *[[Patrick Boyd]] *[[Pam Brasier]] *[[Harriet Casdin-Silver]] *[[Greg Cherry]] *[[Melissa Crenshaw]] *[[Cross, Lloyd | Lloyd Cross]] *[[Salvador Dali]] *[[Rebecca Deem]] *[[Frank DeFreitas]] *[[Yuri Denisyuk]] *[[Georges Dyens]] *[[Phil Edelbrock]] *[[Gregg E. Favalora]] *[[Dennis Gabor]] *[[Yves Gentet]] *[[Andres Ghisays]] *[[Nancy J. Gorglione]] *[[Michael Harrison]] *[[Dr. Jeong]] T. J. *[[Frithioff Johansen]] *[[Pearl John]] *[[Colin Kaminski]] *[[John Kaufman]] *[[Roderic Lakes]] *[[Emmett Leith]] *[[Sharon McCormack]] *[[Mike Medora]] *[[Ronnie Michael]] *[[Lon Moore]] *[[Rob Munday]] *[[August Muth]] *[[Ikuo Nakamura]] *[[Anna Maria Nicholson]] *[[Caroline Palmer]] *[[Dinesh Padiyar]] *[[Joy Padiyar]] *[[John Pecora]] *[[Andrew Pepper]] *[[Hart Perry]] *[[Jerry Pethick]] *[[Nicholas Phillips]] *[[Greg Quinn]] * [[Rallison, Richard | Richard Rallison]] *[[Al Razutis]] *[[Jonathan Ross]] *[[Graham Saxby]] *[[Dan Schweitzer]] *[[Mark Segal]] *[[Walter Spierings]] *[[Anait Stephens]] *[[Fred Unterseher]] *[[Juris Upatnieks]] *[[Doris Vila]] *[[John Webster]] *[[Edward Wesly]] *[[Mieczyslaw Wolfke]] *[[Sergey Vorobyov]] *[[Sergey Zharkiy]] </div> 0d185425791f855f1c57a6923617e8d36b0a3380 0 843 1919 1777 2013-05-14T23:04:28Z Jsfisher 1 wikitext text/x-wiki {{Note}} This is the resume of Richard Rallison as it appeared on the Ralcon website and his obituary as it appeared in the [http://news.hjnews.com/ Logan Herald Journal]. == Education == *Engineering Studies, Utah State University, 1964-1968 *B.S.E.E., University of Utah, 1969-1973 (Cum Laude) *M.S.E.E. Laser Systems, U.S.C. 1974-75 (not completed) *Ph.D. Electro Optical Engineering, Honorary, USU 1995 == Experience and prior work == Approximately 35 years of professional or technical grade experience. Has been engaged in development work of CO2 Waveguide, Co-Axial Cadmium, Doubled "blue" Yag and Dye lasers at Hughes Aircraft for space communications, countermeasures and underwater communications. Performed ION laser design upgrades at American Laser Corp. and fabricated a novel multiple pass Ruby laser system for Dikrotek. Experienced with diode lasers including fabrication of a small bar code scanner for that coupled a diode laser, grin rod and focusing holographic scanner together. Another device developed and co patented with IBM splits diode laser light into polarized components and replaces a Wollaston prism. An early commercial success for IBM was the development of holographic scanner fabrication methods in 1979, followed by many years of development in Holographic elements, devices and systems and sales of Holographic Optical Element (HOE) fabrication technology to IBM, Pilkington (UK), Holosonics, Seimens, Raven Holographics in England, Portson Inc of Kansas., APA Optics of MN, Northrop corp of CA., Metrologic Instruments of NJ, Process Instruments of SLC, Bell Resources in Australia and Terabeam of Seattle. Work for NASA beginning in 1990 to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have begun. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s. Many spectrographic optical designs, head mounted display designs and some holographic memory designs have been made and brass-boarded. Some have become commercial products. Mr. Rallison has served as a consultant in Diffractive Optics for dozens of companies and has given numerous lectures on holography at the University of Utah, USU and Lake forest College as well as occasional invitations to give paid tutorials in industry. Other work includes the design and fabrication of novel HUD optics for the Air Force on an SBIR grant and an investigation of new holographic recording polymers for the Army NVL on an SBIR contracts. Contracts have been successfully completed for the army at Aberdeen where 5 HMDs were designed fabricated and delivered. Work for VIO in Seattle involved design and fabrication of Stereo Color HMDs or their components. 10 years of work on NASA contracts to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have been attempted. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s such as telecom receivers for free space interconnects developed for another Seattle company named Terabeam, co-founded by RD Rallison. He has fabricated multi lens arrays, gratings, HUDs, notch filters, Fourier filters, scanners, co-phasal multiplexed gratings, spectrophotometer gratings and filters, reflectors, diffusers, depixelators and assorted other HOEs. He owned and operated a company that produced millions of high quality display holograms for commercial use over a 10-year period. He worked as a Video Engineer and Cameraman for a CBS affiliate and prior to that performed work related to weather modification at the Utah Water Research Lab while also producing commercial light shows and devices for entertainment type productions. == Position at Ralcon == Ralcon Corp. is a vehicle for Mr. Rallison to consult in Optics and develop products. He owns an 8000 square foot facility in Paradise, Utah where laser and Holographic Optics development work has been going on since 1985.The facility is equipped with Argon, Yag, Dye, Nitrogen, HeNe, Ruby and various Diode lasers. Four floating stable tables of various sizes in well insulated rooms provide the basic optical beds and each has its own Argon, HeNe and YAG laser. A machine shop with a variety of glass shaping and polishing machinery compliment the holographic optical fabrication facility. Ralcon Development Lab (RDL) ceased commercial business in June of 2004 at the request the Cache County planning and zoning commission. Commercial customers of RDL have been referred to Wasatch Photonics in Logan UT, which was created in part to continue the work of RDL. Work at RDL is limited to research for NASA GSFC and other government labs. == Professional Affiliations == *Institute of Electrical and Electronic Engineers *Sigma Tau (Honorary Society) *Society of Photo Optical and Instrumentation Engineers(SPIE) *Optical Society of America (OSA) *Aircraft Owners and Pilots association (AOPA) == Licenses == *First Class Radio Telephone *Private Pilot, SEL, RH, Glider, Hang Glider *CDL -class A-air-trailer == Patents == * #4,913,990 "method of tuning a volume phase hologram" * #5,303,085 and #5,619,377 "Optically corrected helmet mounted display" * #4,950,067 "optical system that helps reduce eye strain" * #5,291,316 "Information display system having Transparent Holographic Optical Element" * #5,602,657 "Hologram system having hologram layers with rotationally offset Bragg planes" * #5,519,517 "Method and apparatus for holographically record and reproduce images in a sequential manner" * #6,097,543 "Personal Visual Display" * #5,991,087 "Non-orthogonal plate in a virtual reality or heads up display" * #5,991,085 "Head mounted personal visual display apparatus with image generator and holder" * #5,949,583 "Head mounted display with image generator, fold mirror and mirror for transmission to the eye position of the user" * #5,945,967 "speckle depixelator" * #5,903,396 "Intensified visual display" * #5,903,395 "Personal visual display system" * #5,864,326 "Depixelated visual display" * #5,751,425 "Raman spectroscopy apparatus and a method for continuous chemical analysis of fluid streams" * #6,100,975 "Raman spectroscopy apparatus and method using external cavity laser for continuous chemical analysis of sample streams" * #5,673,151 "Image correction in virtual reality and heads up displays" * #5,642,227 " Optical correction for virtual reality and heads up displays" * #6,678,079 “Transceiver for a wireless optical telecommunication system “ * #6,608,708"System and method for using a holographic optical element in a wireless telecommunication system receiver” * #6,369,952 “Head-mounted personal visual display apparatus with image generator and holder” * #6,160,666 "Personal visual display system” == Awards == *Dept of Defense SBIR Quality Award == Publications == Follow &lt;a href="/web/20080514140659/http://www.xmission.com/~ralcon/publications.html"&gt;this&lt;/a&gt; link to see our publications list, including links to online versions when available. ==Obituary== [[File:LHJ_Rallison.jpg|left]] PARADISE - Richard Dennis Rallison, 64, passed away Sept. 16, 2010, while paragliding. Born Dec. 24, 1945, at Logan Regional Hospital, he was the youngest son of Robert Leo and Lucile Rallison. A longtime resident of Cache Valley, Richard graduated from Logan High School in 1964. Richard went on to earn a bachelor's degree in electrical engineering from the University of Utah. Richard married Ruth Napp on Nov. 26, 1974, and the couple was sealed on June 21, 1977, in the Salt Lake City LDS Temple. They have three children, Ray, Robert and Regan. An avid inventor and pioneer in the field of optics, he contributed to projects such as the Hubble Space Telescope, the Subaru Telescope in Hawaii, the optical disc used in bar-code scanners, as well as many other projects involving holography. He was awarded an honorary Doctorate in Electro-Optical Engineering from Utah State University in 1995 for his accomplishments. Richard always had an adventurous spirit and could often be found riding his motorcycle around hairpin curves, wind-surfing, or flying whatever aircraft he happened to own at the time. The sound of his various aircrafts was a noise his neighbors had grown accustomed to over the years. His love of adventure, his sense of humor and his generosity will be sorely missed. He is survived by his wife Ruth, sons Ray (Heidi), of Seattle, Wash.; Robert (Tori), Nibley, Utah; and his daughter Regan Saunders (Christian), Logan, Utah; grandchildren, Sherice, Gabriele, Brianna, and Jack Rallison; brothers Robert E. Rallison (Lorraine, Deceased), Marvin (Beth), Salt Lake City; sisters Anna Lu LaPray (Tony), Highland; Mareta, Pittsburg, Penn.; and numerous nephews, nieces and cousins. Preceded in death by his parents, Bernice (Larchide), and Orval Rallison (Vaunda). A viewing will be held on Tuesday, Sept., 21, at the Allen Hall Mortuary, 34 E. Center St. in Logan from 6 to 8 p.m. Funeral services will be held at the Paradise 2nd ward chapel on Wednesday Sept. 22, beginning at noon, with a viewing prior from 10:30 to 11:30 a.m. at the church. Condolences and thoughts may be expressed to the family online at www.allenmortuaries.net. A few paragraphs is hardly enough to sum up a lifetime of achievements; for more about Richard, visit www.ralcon.com or www.facebook.com/richard.rallison. Published in Logan Herald Journal on September 19, 2010 [[Category:People]] [[Category:Rallison]] cde6b41382fc08cac18fd44b62ecabf7f19157d1 1940 1919 2013-05-15T01:38:41Z Jsfisher 1 wikitext text/x-wiki [[File:FB_Rallison.jpg]] {{Note}} This is the resume of Richard Rallison as it appeared on the Ralcon website and his obituary as it appeared in the [http://news.hjnews.com/ Logan Herald Journal]. == Education == *Engineering Studies, Utah State University, 1964-1968 *B.S.E.E., University of Utah, 1969-1973 (Cum Laude) *M.S.E.E. Laser Systems, U.S.C. 1974-75 (not completed) *Ph.D. Electro Optical Engineering, Honorary, USU 1995 == Experience and prior work == Approximately 35 years of professional or technical grade experience. Has been engaged in development work of CO2 Waveguide, Co-Axial Cadmium, Doubled "blue" Yag and Dye lasers at Hughes Aircraft for space communications, countermeasures and underwater communications. Performed ION laser design upgrades at American Laser Corp. and fabricated a novel multiple pass Ruby laser system for Dikrotek. Experienced with diode lasers including fabrication of a small bar code scanner for that coupled a diode laser, grin rod and focusing holographic scanner together. Another device developed and co patented with IBM splits diode laser light into polarized components and replaces a Wollaston prism. An early commercial success for IBM was the development of holographic scanner fabrication methods in 1979, followed by many years of development in Holographic elements, devices and systems and sales of Holographic Optical Element (HOE) fabrication technology to IBM, Pilkington (UK), Holosonics, Seimens, Raven Holographics in England, Portson Inc of Kansas., APA Optics of MN, Northrop corp of CA., Metrologic Instruments of NJ, Process Instruments of SLC, Bell Resources in Australia and Terabeam of Seattle. Work for NASA beginning in 1990 to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have begun. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s. Many spectrographic optical designs, head mounted display designs and some holographic memory designs have been made and brass-boarded. Some have become commercial products. Mr. Rallison has served as a consultant in Diffractive Optics for dozens of companies and has given numerous lectures on holography at the University of Utah, USU and Lake forest College as well as occasional invitations to give paid tutorials in industry. Other work includes the design and fabrication of novel HUD optics for the Air Force on an SBIR grant and an investigation of new holographic recording polymers for the Army NVL on an SBIR contracts. Contracts have been successfully completed for the army at Aberdeen where 5 HMDs were designed fabricated and delivered. Work for VIO in Seattle involved design and fabrication of Stereo Color HMDs or their components. 10 years of work on NASA contracts to make 400 mm diameter LIDAR scanners for use @ 1064, 532 and 355 nm has been completed and 1 meter contracts have been attempted. The Lidar scanners have led to the development of novel designs and design software to compensate for arbitrary wavelength shifts between the construction wavelengths and the end use wavelengths of generalized HOEs or diffractive Optical Elements (DOE)s such as telecom receivers for free space interconnects developed for another Seattle company named Terabeam, co-founded by RD Rallison. He has fabricated multi lens arrays, gratings, HUDs, notch filters, Fourier filters, scanners, co-phasal multiplexed gratings, spectrophotometer gratings and filters, reflectors, diffusers, depixelators and assorted other HOEs. He owned and operated a company that produced millions of high quality display holograms for commercial use over a 10-year period. He worked as a Video Engineer and Cameraman for a CBS affiliate and prior to that performed work related to weather modification at the Utah Water Research Lab while also producing commercial light shows and devices for entertainment type productions. == Position at Ralcon == Ralcon Corp. is a vehicle for Mr. Rallison to consult in Optics and develop products. He owns an 8000 square foot facility in Paradise, Utah where laser and Holographic Optics development work has been going on since 1985.The facility is equipped with Argon, Yag, Dye, Nitrogen, HeNe, Ruby and various Diode lasers. Four floating stable tables of various sizes in well insulated rooms provide the basic optical beds and each has its own Argon, HeNe and YAG laser. A machine shop with a variety of glass shaping and polishing machinery compliment the holographic optical fabrication facility. Ralcon Development Lab (RDL) ceased commercial business in June of 2004 at the request the Cache County planning and zoning commission. Commercial customers of RDL have been referred to Wasatch Photonics in Logan UT, which was created in part to continue the work of RDL. Work at RDL is limited to research for NASA GSFC and other government labs. == Professional Affiliations == *Institute of Electrical and Electronic Engineers *Sigma Tau (Honorary Society) *Society of Photo Optical and Instrumentation Engineers(SPIE) *Optical Society of America (OSA) *Aircraft Owners and Pilots association (AOPA) == Licenses == *First Class Radio Telephone *Private Pilot, SEL, RH, Glider, Hang Glider *CDL -class A-air-trailer == Patents == * #4,913,990 "method of tuning a volume phase hologram" * #5,303,085 and #5,619,377 "Optically corrected helmet mounted display" * #4,950,067 "optical system that helps reduce eye strain" * #5,291,316 "Information display system having Transparent Holographic Optical Element" * #5,602,657 "Hologram system having hologram layers with rotationally offset Bragg planes" * #5,519,517 "Method and apparatus for holographically record and reproduce images in a sequential manner" * #6,097,543 "Personal Visual Display" * #5,991,087 "Non-orthogonal plate in a virtual reality or heads up display" * #5,991,085 "Head mounted personal visual display apparatus with image generator and holder" * #5,949,583 "Head mounted display with image generator, fold mirror and mirror for transmission to the eye position of the user" * #5,945,967 "speckle depixelator" * #5,903,396 "Intensified visual display" * #5,903,395 "Personal visual display system" * #5,864,326 "Depixelated visual display" * #5,751,425 "Raman spectroscopy apparatus and a method for continuous chemical analysis of fluid streams" * #6,100,975 "Raman spectroscopy apparatus and method using external cavity laser for continuous chemical analysis of sample streams" * #5,673,151 "Image correction in virtual reality and heads up displays" * #5,642,227 " Optical correction for virtual reality and heads up displays" * #6,678,079 “Transceiver for a wireless optical telecommunication system “ * #6,608,708"System and method for using a holographic optical element in a wireless telecommunication system receiver” * #6,369,952 “Head-mounted personal visual display apparatus with image generator and holder” * #6,160,666 "Personal visual display system” == Awards == *Dept of Defense SBIR Quality Award == Publications == Follow &lt;a href="/web/20080514140659/http://www.xmission.com/~ralcon/publications.html"&gt;this&lt;/a&gt; link to see our publications list, including links to online versions when available. ==Obituary== [[File:LHJ_Rallison.jpg|left]] PARADISE - Richard Dennis Rallison, 64, passed away Sept. 16, 2010, while paragliding. Born Dec. 24, 1945, at Logan Regional Hospital, he was the youngest son of Robert Leo and Lucile Rallison. A longtime resident of Cache Valley, Richard graduated from Logan High School in 1964. Richard went on to earn a bachelor's degree in electrical engineering from the University of Utah. Richard married Ruth Napp on Nov. 26, 1974, and the couple was sealed on June 21, 1977, in the Salt Lake City LDS Temple. They have three children, Ray, Robert and Regan. An avid inventor and pioneer in the field of optics, he contributed to projects such as the Hubble Space Telescope, the Subaru Telescope in Hawaii, the optical disc used in bar-code scanners, as well as many other projects involving holography. He was awarded an honorary Doctorate in Electro-Optical Engineering from Utah State University in 1995 for his accomplishments. Richard always had an adventurous spirit and could often be found riding his motorcycle around hairpin curves, wind-surfing, or flying whatever aircraft he happened to own at the time. The sound of his various aircrafts was a noise his neighbors had grown accustomed to over the years. His love of adventure, his sense of humor and his generosity will be sorely missed. He is survived by his wife Ruth, sons Ray (Heidi), of Seattle, Wash.; Robert (Tori), Nibley, Utah; and his daughter Regan Saunders (Christian), Logan, Utah; grandchildren, Sherice, Gabriele, Brianna, and Jack Rallison; brothers Robert E. Rallison (Lorraine, Deceased), Marvin (Beth), Salt Lake City; sisters Anna Lu LaPray (Tony), Highland; Mareta, Pittsburg, Penn.; and numerous nephews, nieces and cousins. Preceded in death by his parents, Bernice (Larchide), and Orval Rallison (Vaunda). A viewing will be held on Tuesday, Sept., 21, at the Allen Hall Mortuary, 34 E. Center St. in Logan from 6 to 8 p.m. Funeral services will be held at the Paradise 2nd ward chapel on Wednesday Sept. 22, beginning at noon, with a viewing prior from 10:30 to 11:30 a.m. at the church. Condolences and thoughts may be expressed to the family online at www.allenmortuaries.net. A few paragraphs is hardly enough to sum up a lifetime of achievements; for more about Richard, visit www.ralcon.com or www.facebook.com/richard.rallison. Published in Logan Herald Journal on September 19, 2010 [[Category:People]] [[Category:Rallison]] 8761b3a5c4c7539f94e9940b38160f71f7180497 6 870 1920 2013-05-14T23:04:57Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 871 1923 2013-05-14T23:14:37Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 485 1924 1797 2013-05-14T23:22:15Z Jsfisher 1 wikitext text/x-wiki [http://rudieberkhout.home.mindspring.com/home.htm Rudie Berkhout] Rudie Berkhout was a Artist/Holographer from Leeds NY. He had an extensive list of publications about holography and regularly exhibited his work. Born in Amsterdam, Berkhout came to the United States in 1974 with a background in engineering and lighting to study at the New York School of Holography. He later researched white light holographic techniques and pulsed holography at the New York Art Alliance laboratories. He created the first flat display system for holographic movies (Integral holography or holographic stereograms first developed by Lloyd Cross) while at the Holographic Film Company in New York (founded by cinematographer Hart Perry). Until this time, holographic stereograms had been viewed only in the round. Berkhout also designed and built a time-lapse recording system to enable artists to capture as much as four hours of movement in a single hologram. A major contribution to the medium was his work in color control and image multiplication which resulted in his breathtaking "Twelve Milliwatt Boogie" first exhibited in 1979 at the Museum of Holography, New York. This stunning piece set a standard in white-light transmission holography with its boldly-colored geometric figures floating in three-dimensional space. Rudie Berkhout passed away from a heart attack on Tuesday 16 September, 2008. ==Rudie Berkhout, 1946 - 2008== Rudie Berkhout was among the very few artists in the world who chose light as the principal medium for their work. Combining his passion for technology with his drive to explore his own aesthetic frontiers, Rudie found his ideal métier in the arcane disciplines of holography and came to be known as one of it's foremost practitioners. His work received abundant recognition by those who were also open to a new vision for a new century. Mastering the limited technology available to him in the pre-digital world in which he lived and worked, he was clearly a man ahead of his time. [[File:RudieBerkhout.jpg|left]] Born in post-war Amsterdam, Berkhout's early love of mechanics led him to technical school, where he discovered the magic of lighting. By high school he was creating light shows in the legendary psychedelic clubs of Amsterdam. He met his life partner, Hudson Talbott, in one of those clubs, and together they set out on travels throughout the world, eventually coming to New York in late 1974. The great sweep of the city's creative energy inspired Berkhout to seek out a medium that he could call his own. He found it in 1975 when he saw his first holography show at the International Center for Photography. Immediately, he immersed himself in classes but quickly surpassed his teachers and began to teach himself. In 1979 he had his first one-man show at the Museum of Holography in New York, and recognition of his work grew quickly. As Rudie's exploration continued, so did his reputation as master, with a solo show at the Palazzo Fortuny during the 1982 Venice Biennale, The Gulbenkian Museum in Lisbon, the Grace Borgnicht Gallery in New York, The Fukuoka Museum in Japan, and the first show ever of holographic art at the Whitney Museum of American Art. His work is included in the permanent collections of museums in Germany, Italy, Japan, The Netherlands, Spain, and the USA. Among his corporate commissions are major installations for the University of Wisconsin, The Bank of America, and the Netherlands National Dept. of Transportation Building. At the time of his death, Rudie was exploring new directions with light. Seeking ways of bringing the playful, otherworldly nature of light into the home environment, he combined laser lights with holographic elements to create ambient lighting for both domestic and commercial interiors. He was thrilled with the immediate public response to his new direction when, on the afternoon of Sept. 16, 2008, he was suddenly taken by a massive heart attack, during a phone conversation with his sister in Amsterdam. They were speaking of the new frontiers and his journey forward. True to his visionary nature to the last moment, he used a word that could be applied to his entire life, his work and the legacy he has left us. For Rudie Berkhout, it was all "wondrous". b6dca067d08eccda9f31135dd8086f681ea2c287 1926 1924 2013-05-14T23:24:28Z Jsfisher 1 wikitext text/x-wiki [http://www.rudieberkhoutcollection.com/ Rudie Berkhout] [[File:RudieBerkhout.jpg|left]] Rudie Berkhout was a Artist/Holographer from Leeds NY. He had an extensive list of publications about holography and regularly exhibited his work. Born in Amsterdam, Berkhout came to the United States in 1974 with a background in engineering and lighting to study at the New York School of Holography. He later researched white light holographic techniques and pulsed holography at the New York Art Alliance laboratories. He created the first flat display system for holographic movies (Integral holography or holographic stereograms first developed by Lloyd Cross) while at the Holographic Film Company in New York (founded by cinematographer Hart Perry). Until this time, holographic stereograms had been viewed only in the round. Berkhout also designed and built a time-lapse recording system to enable artists to capture as much as four hours of movement in a single hologram. A major contribution to the medium was his work in color control and image multiplication which resulted in his breathtaking "Twelve Milliwatt Boogie" first exhibited in 1979 at the Museum of Holography, New York. This stunning piece set a standard in white-light transmission holography with its boldly-colored geometric figures floating in three-dimensional space. Rudie Berkhout passed away from a heart attack on Tuesday 16 September, 2008. [[Category:People]] 8e0f59076ee08a59d427a8c9816bfebbe592d785 6 872 1925 2013-05-14T23:22:41Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 873 1928 2013-05-14T23:30:22Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 456 1929 1765 2013-05-14T23:31:18Z Jsfisher 1 wikitext text/x-wiki [[Image:PaulDBarefoot.gif]] == ''Paul D. Barefoot'' == ''President:Holophile, Inc.'' Paul Barefoot saw his first hologram in New York at the International Center of Photography exhibition, ''Holography '75: The First Decade'', produced by Jody Burns and Posy Jackson. It was there that he caught "Holography Fever." Within months, he moved to New York from his hometown of Charlotte, NC, where he was Director of Marketing for a graphic arts company and a C130 pilot with the North Carolina National Guard. In November, 1975 he founded Holophile, Inc. to market holography to corporations and nonprofit clients. He also began an affiliation with John Bliss Associates, Inc. (later, Bliss, Barefoot & Associates, Inc.), who served as Public Relations counsel to the Museum of Holography from its inception in 1976. In 1977, Barefoot worked with Museum of Holography founder, Rosemary Jackson, to organize a traveling exhibition of the Museum's inaugural exhibition, ''Through the Looking Glass''. It opened in Toronto and traveled to art, science and children's museums throughout the U.S. Public response was overwhelmingly positive.The exhibition was booked with institutions continuously for ten years -- not returning to New York until its retirement in 1987. During that time, Barefoot took ''Looking Glass'' to Australia for an appearance at the Adelaide Festival of Arts, and to Jerusalem where it broke the all-time attendance record at the Israel Museum In1988, Barefoot began circulating the Museum's second traveling exhibition, ''FutureSight: Innovations in Art Holography''. This exhibition, curated by Rene Barilleaux, traveled to art museums and galleries in the U.S., plus a tour of four New Zealand museums in Auckland, Wellington, Christchurch and Dunedin. In 1992, Barefoot organized a new traveling exhibition entitled, ''The Nature of Holography''. A second show (of the same name) was developed in 1993 to meet the growing demand by art, science, and children's museums. A third exhibition, ''Holography: Making Faces'', was introduced in 2007. These exhibitions, which feature images from the Holophile Collection, are still in circulation. (See complete listing of host institutions since 1977 [http://www.holophile.com/html/exhibit.htm]) Since founding Holophile in 1975, Barefoot has worked as a producer of custom holograms for use by corporate, not-for-profit and government clients, including The American Gas Association, BP Oil de Venezuela S.A., Canary Islands Tourism Board, The Coca Cola Company, IBM, National Security Agency (NSA), M & T Chemicals, Inc., PricewaterhouseCoopers, Samsung Electronics, Pfizer Pharmaceuticals, Raytheon Canada, Ltd and The Weizmann Institute of Science. Barefoot continues to work in holography and other three-dimensional imaging technologies through his company, Holophile, Inc. ([http://www.holophile.com]), located in Killingworth, CT. 7864de9393dbe3d882038925e85c40d54eb02db2 1933 1929 2013-05-15T00:50:33Z Jsfisher 1 wikitext text/x-wiki [[Image:PaulDBarefoot.gif]] == ''Paul D. Barefoot'' == ''President:Holophile, Inc.'' Paul Barefoot saw his first hologram in New York at the International Center of Photography exhibition, ''Holography '75: The First Decade'', produced by Jody Burns and Posy Jackson. It was there that he caught "Holography Fever." Within months, he moved to New York from his hometown of Charlotte, NC, where he was Director of Marketing for a graphic arts company and a C130 pilot with the North Carolina National Guard. In November, 1975 he founded Holophile, Inc. to market holography to corporations and nonprofit clients. He also began an affiliation with John Bliss Associates, Inc. (later, Bliss, Barefoot & Associates, Inc.), who served as Public Relations counsel to the Museum of Holography from its inception in 1976. In 1977, Barefoot worked with Museum of Holography founder, Rosemary Jackson, to organize a traveling exhibition of the Museum's inaugural exhibition, ''Through the Looking Glass''. It opened in Toronto and traveled to art, science and children's museums throughout the U.S. Public response was overwhelmingly positive.The exhibition was booked with institutions continuously for ten years -- not returning to New York until its retirement in 1987. During that time, Barefoot took ''Looking Glass'' to Australia for an appearance at the Adelaide Festival of Arts, and to Jerusalem where it broke the all-time attendance record at the Israel Museum In1988, Barefoot began circulating the Museum's second traveling exhibition, ''FutureSight: Innovations in Art Holography''. This exhibition, curated by Rene Barilleaux, traveled to art museums and galleries in the U.S., plus a tour of four New Zealand museums in Auckland, Wellington, Christchurch and Dunedin. In 1992, Barefoot organized a new traveling exhibition entitled, ''The Nature of Holography''. A second show (of the same name) was developed in 1993 to meet the growing demand by art, science, and children's museums. A third exhibition, ''Holography: Making Faces'', was introduced in 2007. These exhibitions, which feature images from the Holophile Collection, are still in circulation. (See complete listing of host institutions since 1977, http://www.holophile.com/html/exhibit.htm) Since founding Holophile in 1975, Barefoot has worked as a producer of custom holograms for use by corporate, not-for-profit and government clients, including The American Gas Association, BP Oil de Venezuela S.A., Canary Islands Tourism Board, The Coca Cola Company, IBM, National Security Agency (NSA), M & T Chemicals, Inc., PricewaterhouseCoopers, Samsung Electronics, Pfizer Pharmaceuticals, Raytheon Canada, Ltd and The Weizmann Institute of Science. Barefoot continues to work in holography and other three-dimensional imaging technologies through his company, Holophile, Inc. (http://www.holophile.com), located in Killingworth, CT. 9e6b0735e86e83e8b05f0400ce36a5919b15c828 0 395 1930 1729 2013-05-15T00:42:55Z Jsfisher 1 wikitext text/x-wiki [[Image:JBlyth.jpg]] After graduating in 1973 in Applied Chemistry he worked in a company with dichromated gelatin, unrelated to holography. In ’77, he was amazed to see a holographic pendant made using the very material he was researching. His life ‘changed for ever’. He subsequently worked on photopolymer materials for Ilford, which became the subject for an MPhil at Wolverhampton Polytechnic. Since ’91 he has been involved in ‘blue sky’ research at the Institute of Biotechnology in Cambridge, UK. Jeff is the recipient of the Royal Photographic Society’s Saxby award for 2003. 6461413dcfd42acfffc244542ee8c1ba97a503b7 1931 1930 2013-05-15T00:43:36Z Jsfisher 1 wikitext text/x-wiki [[Image:JBlyth.jpg]] After graduating in 1973 in Applied Chemistry he worked in a company with dichromated gelatin, unrelated to holography. In ’77, he was amazed to see a holographic pendant made using the very material he was researching. His life ‘changed for ever’. He subsequently worked on photopolymer materials for Ilford, which became the subject for an MPhil at Wolverhampton Polytechnic. Since ’91 he has been involved in ‘blue sky’ research at the Institute of Biotechnology in Cambridge, UK. Jeff is the recipient of the Royal Photographic Society’s Saxby award for 2003. [[Category:People]] 052bd51b2f17a4342e5bb43632567be32db2f624 0 209 1932 1639 2013-05-15T00:45:28Z Jsfisher 1 wikitext text/x-wiki [[Image:DBattin.jpg]] [http://laser.physics.sunysb.edu/~dave/ Dave's Web Site] IT all started for me in the Museum of Holography, in the late 70s. after making one visit i was hooked for life! Seeing what could be done was unbeleivable..... I then joined as a member and started to read any information i could absorb. Attending college in Boston I found all kinds of new info at the college libaries. Upon graduation from college I headded west, finding work near Los Angles in a large machine shop, I found this very convenient for making tooling for my holographic components. After leaving LA and returning to New York, I continued my holographic studies, and met a fellow holographer, Mark Segal (owner of now defunct Spatial Images International)at this lab we produced a large ammout of DCG holography. A short time later a head hunter contacted me about a job working for company called Farirchild Weston Space and Camera, the job was for an optical engineer, I couldn't wait for the interview! They hired me in a flash! The optics lab was about 2500 sq.ft of total OPTICS! Lenses, mirrors, lasers a gigantic isolation table (20 tons+), I spent the next five years building telephoto lenses ths size of 55 gallon drums and tiny ccd cameras that would fit in matchbox! This is where I really learned about the nature of light and optics. 7b17da5426f404ca0aa67cd6a5bf1d1931d4fb51 0 866 1934 1906 2013-05-15T01:30:22Z Jsfisher 1 wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in two Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 and http://holoforum.org/forum/viewtopic.php?f=7&t=497 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} 7e9307ef77f555711c6831820f5ce63fab5eb405 0 424 1935 1749 2013-05-15T01:32:47Z Jsfisher 1 Jsfisher moved page [[Loyd Cross]] to [[Cross, Lloyd]] wikitext text/x-wiki [[Image:Lcross.jpg]] ad8cf59eb04fa1975b0157f132d7cf769aa2afcf 0 406 1941 964 2013-05-15T01:45:41Z Jsfisher 1 wikitext text/x-wiki =Holography Glossary= [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- ; Lamp black : Pure carbon pigment made from soot deposited from burning oils. ; Laser : An acronym for Light Amplification by the Stimulated Emission of Radiation. A laser is a device that emits a light beam that has special qualities. Most lasers are a pure color and travel in a beam without spreading. ; Lead acetate : Crystalline, highly poisonous powder used in some toning and intensifying solutions. ; Latensification : Method of increasing relative film speed by fogging after exposure and before development. It can be achieved by chemical or light means. ; Lenticular screen : Lens system consisting of a screen containing a number of small lenses. There are two applications of lenticular systems. They are used in some exposure meters to gather light and to determine the angle of acceptance of light by the meter. A lenticular screen consisting of a number of lenses set into rows can be used at the camera stage to produce stereoscopic images by synthesizing binocular vision. ; Light trap : System of entry to a darkroom which allows easy access, but prevents unwanted light from entering. ; Linked Ring Brotherhood : Group of pictorialist photographers who broke away from the Photographic Society of Great Britain. Existed between 1892-1910. ; Lippmann process : Early color process invented by Professor Gabriel Lippmann (1845-1921). Light first passed through an almost transparent emulsion layer and was then reflected back by a layer of mercury. The interference between reflected and incident light produced a latent image in the emulsion which could be given b&w processing, but when backed with a mirror appeared in color. ; Local control : Method of controlling the final quality of a print by increasing or decreasing the exposure given to localized areas of the print by selective masking. 9dccc4fb31579773587fcb7331a567012d91cbc9 0 279 1942 406 2013-05-15T02:05:10Z Jsfisher 1 /* Spatial Frequency */ wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== <center><math>\displaystyle f = \frac{sin{\theta_2} - sin{\theta_1}}{\lambda}</math></center> Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: <center><math>d = \frac{\lambda}{sin{\theta_2} - sin{\theta_1}}</math></center> (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say (while I nodded off!). http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html [[Image:DiffractionEQ.gif]] They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) [[Image:EdExample1.gif]] Just like it should. If we repeat the above but with m = 2, we get: [[Image:EdExample2.gif]] Unh-unh! sin of an angle can’t be >1! (This is called a [[http://en.wikipedia.org/wiki/Evanescent_wave evanescent]] wave and is not propegated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) [[Image:EdExample3.gif]] (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: [[Image:EdExample4.gif]] Replacing m by 2, [[Image:EdExample5.gif]] When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm [[Image:EdExample6.gif]] Replacing m by 2, [[Image:EdExample7.gif]] This time we can get away by replacing m by 3, [[Image:EdExample8.gif]] So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== 9dbba57c2818e204be603a2ac5c9594ba81a5e09 1943 1942 2013-05-15T02:37:06Z Jsfisher 1 /* Diffraction */ wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== <center><math>\displaystyle f = \frac{sin{\theta_2} - sin{\theta_1}}{\lambda}</math></center> Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: <center><math>d = \frac{\lambda}{sin{\theta_2} - sin{\theta_1}}</math></center> (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say (while I nodded off!). http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html : <math>\sin{\theta_{out}} = \sin{\theta_{in}} + m \lambda f</math> They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) : <math> \begin{array}{rcl} \sin{\theta_{out}} & = & \sin{(-40)} + 1 \times 0.000633 \, mm \times 1805 \, c/mm \\ \sin{\theta_{out}} & = & -0.643 + 1.143 \\ \sin{\theta_{out}} & = & 0.5 \\ \theta_{out} & = & 30^\circ \end{array} </math> Just like it should. If we repeat the above but with m = 2, we get: : <math> \begin{array}{rcl} \sin{\theta_{out}} & = & \sin{(-40)} + 2 \times 0.000633 \, mm \times 1805 \, c/mm \\ \sin{\theta_{out}} & = & -0.643 + 2.286 \\ \sin{\theta_{out}} & = & 1.643 \end{array} </math> Unh-unh! sin of an angle can’t be >1! (This is called a [[http://en.wikipedia.org/wiki/Evanescent_wave evanescent]] wave and is not propogated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) [[Image:EdExample3.gif]] : <math> \begin{array}{rcl} f & = & \frac{\sin{10} - \sin{-10}}{633 \, nm} \\ f & = & 548.651... \end{array} </math> (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: \begin{array}{rcl} sin{\theta_{out}} & = & m \lambda f \\ sin{\theta_{out}} & = & 1 \times 0.000633 \, mm \times 550 \, c/mm \\ sin{\theta_{out}} & = & 0.34815 \theta_{out} & = & 20.37^\circ \end{array} Replacing m by 2, \begin{array}{rcl} sin{\theta_{out}} & = & 2 \times 0.000633 \, mm \times 550 \, c/mm \\ sin{\theta_{out}} & = & 0.6963 \theta_{out} & = & 44.1^\circ \end{array} When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm \begin{array}{rcl} sin{\theta_{out}} & = & 1 \times 0.000442 \, mm \times 550 \, c/mm \\ sin{\theta_{out}} & = & 0.2413 \theta_{out} & = & 14.0^\circ \end{array} [[Image:EdExample6.gif]] Replacing m by 2, \begin{array}{rcl} sin{\theta_{out}} & = & 2 \times 0.000442 \, mm \times 550 \, c/mm \\ sin{\theta_{out}} & = & 0.4826 \theta_{out} & = & 29^\circ \end{array} [[Image:EdExample7.gif]] This time we can get away by replacing m by 3, \\begin{array}{rcl} sin{\theta_{out}} & = & 3 \times 0.000442 \, mm \times 550 \, c/mm \\ sin{\theta_{out}} & = & 0.7293 \theta_{out} & = & 46^\circ \end{array} [[Image:EdExample8.gif]] So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== 9c14fb57ebe8028a3c4cf077235a81cd1fb31a10 1944 1943 2013-05-15T03:17:20Z Jsfisher 1 wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== : <math>f = \frac{\sin{\theta_2} - \sin{\theta_1}}{\lambda}</math> Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: : <math>d = \frac{\lambda}{\sin{\theta_2} - \sin{\theta_1}}</math> (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say (while I nodded off!). http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html : <math>\sin{\theta_{out}} = \sin{\theta_{in}} + m \lambda f</math> They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) : <math> \begin{array}{rcl} \sin{\theta_{out}} & = & \sin{(-40)} + 1 \times 0.000633 \, mm \times 1805 \, c/mm \\ \sin{\theta_{out}} & = & -0.643 + 1.143 \\ \sin{\theta_{out}} & = & 0.5 \\ \theta_{out} & = & 30^\circ \end{array} </math> Just like it should. If we repeat the above but with m = 2, we get: : <math> \begin{array}{rcl} \sin{\theta_{out}} & = & \sin{(-40)} + 2 \times 0.000633 \, mm \times 1805 \, c/mm \\ \sin{\theta_{out}} & = & -0.643 + 2.286 \\ \sin{\theta_{out}} & = & 1.643 \end{array} </math> Unh-unh! sin of an angle can’t be >1! (This is called a [[http://en.wikipedia.org/wiki/Evanescent_wave evanescent]] wave and is not propogated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) [[Image:EdExample3.gif]] : <math> \begin{array}{rcl} f & = & (\sin{(10)} - \sin{(-10)}) / 633 \, nm \\ f & = & 548.651... \end{array} </math> (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: : <math>\begin{array}{rcl} \sin{\theta_{out}} & = & m \lambda f \\ \sin{\theta_{out}} & = & 1 \times 0.000633 \, mm \times 550 \, c/mm \\ \sin{\theta_{out}} & = & 0.34815 \\ \theta_{out} & = & 20.37^\circ \end{array}</math> Replacing m by 2, : <math>\begin{array}{rcl} \sin{\theta_{out}} & = & 2 \times 0.000633 \, mm \times 550 \, c/mm \\ \sin{\theta_{out}} & = & 0.6963 \\ \theta_{out} & = & 44.1^\circ \end{array}</math> When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm : <math>\begin{array}{rcl} \sin{\theta_{out}} & = & 1 \times 0.000442 \, mm \times 550 \, c/mm \\ \sin{\theta_{out}} & = & 0.2413 \\ \theta_{out} & = & 14.0^\circ \end{array}</math> [[Image:EdExample6.gif]] Replacing m by 2, : <math>\begin{array}{rcl} \sin{\theta_{out}} & = & 2 \times 0.000442 \, mm \times 550 \, c/mm \\ \sin{\theta_{out}} & = & 0.4826 \\ \theta_{out} & = & 29^\circ \end{array}</math> [[Image:EdExample7.gif]] This time we can get away by replacing m by 3, : <math>\begin{array}{rcl} \sin{\theta_{out}} & = & 3 \times 0.000442 \, mm \times 550 \, c/mm \\ \sin{\theta_{out}} & = & 0.7293 \\ \theta_{out} & = & 46^\circ \end{array}</math> [[Image:EdExample8.gif]] So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== : <math>\sin{\theta_{out}} = m \frac{\lambda_{ill}}{\lambda_{exp}}(\sin{\theta_{obj}} - \sin{\theta_{ref}}) + \sin{\theta_{ill}}</math> [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): : <math>\begin{array}{rcl} \sin{\theta_{out}} & = & m (\lambda_{ill}/\lambda_{exp})(\sin{\theta_{obj}} - \sin{\theta_{ref}} + \sin{\theta_{ill}} \\ \sin{\theta_{out}} & = & 1 (633 \, nm / 633 \, nm)(\sin{(0)} - \sin{(-45)} + \sin{(-45)} \\ \sin{\theta_{out}} & = & 1 \times 1 \times 0.7071 - 0.7071 \\ \sin{\theta_{out}} & = & 0 \\ \theta_{out} & = & 0^\circ \end{array}</math> [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: : <math>\begin{array}{rcl} \sin{\theta_{out}} & = & 1 (633 \, nm / 633 \, nm)(\sin{(0)} - \sin{(-45)} + \sin{(-50)} \\ \sin{\theta_{out}} & = & 1 \times 1 \times 0.7071 - 0.7660 \\ \sin{\theta_{out}} & = & -0.0589 \\ \theta_{out} & = & 3.337^\circ \end{array}</math> [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: : <math>\begin{array}{rcl} \sin{\theta_{out}} & = & 1 (633 \, nm / 633 \, nm)(\sin{(0)} - \sin{(-45)} + \sin{(-40)} \\ \sin{\theta_{out}} & = & 1 \times 1 \times 0.7071 - 0.6428 \\ \sin{\theta_{out}} & = & 0.0643 \\ \theta_{out} & = & 3.687^\circ \end{array}</math> [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== 6b81314d381e207f3d85138e1bf4b018cd899833 1945 1944 2013-05-15T21:43:20Z Jsfisher 1 Reverted edits by [[Special:Contributions/Jsfisher|Jsfisher]] ([[User talk:Jsfisher|talk]]) to last revision by [[User:Colin Kaminski|Colin Kaminski]] wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== [[Image:InterferenceEQ.gif]] Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: [[Image:SpatialEQ.gif]] (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say. (while I nodded off!) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html [[Image:DiffractionEQ.gif]] They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) [[Image:EdExample1.gif]] Just like it should. If we repeat the above but with m = 2, we get: [[Image:EdExample2.gif]] Unh-unh! sin of an angle can’t be >1! (This is called a [[http://en.wikipedia.org/wiki/Evanescent_wave evanescent]] wave and is not propegated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) [[Image:EdExample3.gif]] (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: [[Image:EdExample4.gif]] Replacing m by 2, [[Image:EdExample5.gif]] When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm [[Image:EdExample6.gif]] Replacing m by 2, [[Image:EdExample7.gif]] This time we can get away by replacing m by 3, [[Image:EdExample8.gif]] So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== fbc0f252fcad12b0d9b6f5edee3cef874f031174 0 875 1946 2013-05-15T22:37:41Z Jsfisher 1 Created page with " [[File:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]], Jeff Blyth, Christopher R. Lowe, John ..." wikitext text/x-wiki [[File:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]], Jeff Blyth, Christopher R. Lowe, John F. Pecora. 823cde26ce6cb94a00ab6e5bddb603ac8c100452 1948 1946 2013-05-15T22:38:23Z Jsfisher 1 wikitext text/x-wiki [[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]], Jeff Blyth, Christopher R. Lowe, John F. Pecora. 7c40ca9d24bba8002214572b7c8ddd353b60c0a3 1949 1948 2013-05-15T22:55:16Z Jsfisher 1 wikitext text/x-wiki * [[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]], Gelatin Manufacturers Institute of America. * [[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]], Jeff Blyth, Christopher R. Lowe, John F. Pecora. * [[Media:aa012.pdf | The Theory of the Photographic Process]]. C. E. Kenneth Mees. c2c27fef834b65a0d102799aa08baf8db2363b2a 1951 1949 2013-05-16T00:55:56Z Jsfisher 1 wikitext text/x-wiki * [[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]], Gelatin Manufacturers Institute of America. * [[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]], Jeff Blyth, Christopher R. Lowe, John F. Pecora. 44b141f0a81f584c697da0bf8827ccfe80b23ac1 1952 1951 2013-05-16T01:32:34Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. 7c144b8c035b0bc02486dbf7e5a924a14d5395b1 1954 1952 2013-05-16T02:33:54Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) d8b07e920b712ca8687c19dcaa63ab2fbcbe092f 1955 1954 2013-05-16T22:12:06Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[laserprimer.pdg | Diode Laser Characteristics],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. 82675c7ce282c91ed50ce0f6eb232fe95bfded19 1956 1955 2013-05-16T22:12:15Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[laserprimer.pdf | Diode Laser Characteristics],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. 0afb5e14820766894f535d2d2cf13c580368d2f3 1957 1956 2013-05-16T22:12:35Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. cb729c6efed1df50e733ab1fc9b2dbfb2a3967db 1959 1957 2013-05-17T00:53:42Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * '''[[Media:grains.pdf | Silver Halide Materials]],''' Dinesh Padivar. (The "grains.pdf" document.) * '''[[Media:dye sensitization of holgaphic emulsions | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. d81692ed3dcb197136db36f358bb7e347adae361 1960 1959 2013-05-17T00:54:45Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * '''[[Media:grains.pdf | Silver Halide Materials]],''' Dinesh Padivar. (The "grains.pdf" document.) * '''[[Media:Dye sensitization of holgaphic emulsions | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. d46f102f8ef6571923c8c55bc737499a9a133822 1961 1960 2013-05-17T00:56:22Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * '''[[Media:grains.pdf | Silver Halide Materials]],''' Dinesh Padivar. (The "grains.pdf" document.) * '''[[Media:Dye sensitization of holgaphic emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. d26c15dacc4e47fc4e551a22687e8cef3d028d96 1962 1961 2013-05-17T00:57:20Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * '''[[Media:grains.pdf | Silver Halide Materials]],''' Dinesh Padivar. (The "grains.pdf" document.) * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. 7cf2d34cccb152fe9543323bfa46e6d225c3a409 1964 1962 2013-05-17T01:27:23Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * '''[[Media:grains.pdf | Silver Halide Materials]],''' Dinesh Padivar. (The "grains.pdf" document.) * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. d1a1fb85f3c994dd15bf7f80ca7f4bc514b58a86 6 876 1947 2013-05-15T22:38:06Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 877 1950 2013-05-15T22:55:45Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 878 1953 2013-05-16T01:32:50Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 879 1958 2013-05-16T22:12:48Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 1 1963 1907 2013-05-17T00:58:48Z Jsfisher 1 wikitext text/x-wiki Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms. {{Note | This wiki is undergoing a slow and painful face lift. Please bear with us.| gotcha}} [[File:Olympic.jpg|250px|right|Hologram by Tom B. The Gallery has a stereographic pair version.]] * '''[[Gallery]].''' Great examples of success, failure, and experiments. * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * [[Archives|Archives]] * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). c8a30e6e50ba3df8d1aa556aa7e9dead71d68285 6 880 1965 2013-05-17T01:27:41Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 817 1966 1627 2013-05-17T02:17:27Z Jsfisher 1 wikitext text/x-wiki == Introduction == Rallison introduced a notation for basic recipes for dichromated gelatin emulsions. He use a sequence of three numbers that indicated the quantities of dichromate, gelatin, and water, respectively, used in the formulation. For example, 5-30-200 in Rallison's scheme meant 5 grams of dichromate with 30 grams of gelatin and 200 grams (exactly equivalent to ml) of water made up the recipe. The normal for Rallison's notation was 30 grams of gelatin, while the dichromate and water ratios were allowed to vary. Many amateur holographers use common food-grade gelatin in their work. ''Knox Gelatin'' is the most typical. In the United States, Know Gelatin is available in convenient ¼ oz. packets. An ounce is roughly 28 grams, so it can be convenient to express Rallison recipes using a 7 gram (quarter ounce) reference for gelatin instead of the more common 30 grams. &nbsp;Common Rallison recipes then become: <center> {| width="200" class="wikitable" border=1 |- ! Ralston Recipe !! Rescaled Recipe |- | 5&mdash;30&mdash;250 || 2.3&mdash;7&mdash;58 |- | 10&mdash;30&mdash;600 || 4.7&mdash;7&mdash;140 |} </center> 3a68fd0927d69f4bd8fd5b6799c511047596e45e 1967 1966 2013-05-17T02:20:50Z Jsfisher 1 wikitext text/x-wiki == Introduction == Rallison introduced a notation for basic recipes for dichromated gelatin emulsions. He use a sequence of three numbers that indicated the quantities of dichromate, gelatin, and water, respectively, used in the formulation. For example, 5-30-200 in Rallison's scheme meant 5 grams of dichromate with 30 grams of gelatin and 200 grams (exactly equivalent to ml) of water made up the recipe. The normal for Rallison's notation was 30 grams of gelatin, while the dichromate and water ratios were allowed to vary. Many amateur holographers use common food-grade gelatin in their work. ''Knox Gelatin'' is the most typical. In the United States, Know Gelatin is available in convenient ¼ oz. packets. An ounce is roughly 28.3 grams, so it can be convenient to express Rallison recipes using a 7 gram (quarter ounce) reference for gelatin instead of the more common 30 grams. Common Rallison recipes then become: <center> {| width="200" class="wikitable" border=1 |- ! Ralston Recipe !! Rescaled Recipe |- | 5&mdash;30&mdash;250 || 1.2&mdash;7.1&mdash;59 |- | 10&mdash;30&mdash;600 || 2.4&mdash;7.1&mdash;142 |} </center> 802261e4d01eb758d9dbbbba961c261821a8b7ff 1969 1967 2013-05-17T02:27:48Z Jsfisher 1 wikitext text/x-wiki == Introduction == Rallison introduced a notation for basic recipes for dichromated gelatin emulsions. He use a sequence of three numbers that indicated the quantities of dichromate, gelatin, and water, respectively, used in the formulation. For example, 5-30-200 in Rallison's scheme meant 5 grams of dichromate with 30 grams of gelatin and 200 grams (exactly equivalent to ml) of water made up the recipe. The normal for Rallison's notation was 30 grams of gelatin, while the dichromate and water ratios were allowed to vary. Many amateur holographers use common food-grade gelatin in their work. ''Knox Gelatin'' is the most typical. In the United States, Knox Gelatin is available in convenient ¼ oz. packets. An ounce is roughly 28.3 grams, so it can be useful to express Rallison recipes using a 7.1 gram (quarter ounce) reference for gelatin instead of the more common 30 grams. Common Rallison recipes then become: <center> {| width="200" class="wikitable" border=1 |- ! Ralston Recipe !! Rescaled Recipe |- | 5&mdash;30&mdash;250 || 1.2&mdash;7.1&mdash;59 |- | 10&mdash;30&mdash;600 || 2.4&mdash;7.1&mdash;142 |} </center> 5abba4a1a18ab30988db6c311ac6c44b7146357d 0 204 1968 1625 2013-05-17T02:22:46Z Jsfisher 1 Reverted edits by [[Special:Contributions/Jsfisher|Jsfisher]] ([[User talk:Jsfisher|talk]]) to last revision by [[User:Admin|Admin]] wikitext text/x-wiki [[Category:DCG]] Dichromated gelatin is a light-sensitive material made from gelatin (including ordinary food gelatin such as Knox) and a small amount of either ammonia dichromate or potassium dichromate. <br> == Useful Information == [[A Beginner's Approach to DCG Holography|A Beginner's Approach to DCG Holography]]<br> [[Dichromated Gelatin Chemistry|Dichromated Gelatin Chemistry]] <br> == Notes == The basic formula for dichromated gelatin is water plus gelatin plus either ammonium or potassium dichromate. The amounts of each ingredient influence the characteristics of the result. Exposure energy requirements, color shift, emulsion thickness, etc., are all impacted by the formulation. It is convenient, then, to have a standard for formula reference. Richard Rallison promoted using a system of three numbers to describe a formula—grams of dichromate, grams of gelatin, and grams (milliliters) of water. For example, 8-30-250 would be the notation for a recipe consisting of 8 grams ammonium or potassium dichromate, 30 grams of gelatin, and 250 grams of water. To make comparisons among formulae, the gelatin number is always 30 in Rallison’s notation. The three numbers can be scaled equally up or down for producing different quantities of emulsion. (Personally, I usually scale the numbers to 7.1 grams of gelatin, 7.1 grams being the mass of gelatin in quarter-ounce packet of Knox brand gelatin.) == Thickness and Bandwidth == The ratio of gelatin to water affects the viscosity of the emulsion, and that in turn affects the typical thickness of emulsion on the glass plate. The thickness influences the bandwidth of the final hologram. Rallison reported the following results for emulsions applied by 80 RPM spin coating method: {| border="1" align="center" cellpadding="10" |- ! align="center" scope="col" | '''Formula''' ! align="center" scope="col" | '''Thickness''' ! align="center" scope="col" | '''Bandwidth''' |- | align="center" | xx-30-350 | align="center" | 5 – 6 µm | align="center" | 50 – 150 nm |- | align="center" | xx-30-250 | align="center" | 8 –9 µm | align="center" | 10 – 50 nm |- | align="center" | xx-30-200 | align="center" | 10 – 12 µm | align="center" | 10 – 50 nm |- | align="center" | xx-30-150 | align="center" | 20 – 24 µm | align="center" | ~8 nm |} <br> == Replay Color Shift == The ratio of dichromate to gelatin influences the color shift. The following table has typical values for exposures taken at 514 nm: {| border="1" align="center" cellpadding="10" |- | align="center" scope="col" | Formula | align="center" scope="col" | Color Shift |- | align="center" | 3-30-xxx | align="center" | 630 nm |- | align="center" | 6-30-xxx | align="center" | 590 nm |- | align="center" | 10-30-xxx | align="center" | ~514 nm |} == Exposure Sensitivity == My personal guess at typical exposure requirements for the basic recipe 8-30-300 emulsions. {| border="1" align="center" cellpadding="10" |- | align="center" scope="col" | '''Wavelength''' | align="center" scope="col" | '''Exposure''' |- | align="center" | 405 nm | align="center" | 5 mJ/cm² |- | align="center" | 442 nm | align="center" | 15 mJ/cm² |- | align="center" | 475 nm | align="center" | 40 mJ/cm² |- | align="center" | 488 nm | align="center" | 60 mJ/cm² |- | align="center" | 514 nm | align="center" | 125 mJ/cm² |- | align="center" | 532 nm | align="center" | 200 mJ/cm² |} [[Image:DCGsensVwav.png]] A great many factors may have a dramatic effect on sensitivity, notably humidity and temperature, so the above table is only a point of reference. Sensitivity also varies inversely with the dichromate concentration—halving the amount of dichromate would double the exposure requirement, for example. == Weird DCG Recipes == === 3.6&ndash;30&ndash;467, Chromium Acetate, Ethanol === Markova, Nazarova, and Sharlandjlev, “Control of the Spectral Position of DCG Reflection Holograms,” ''Institute of Optical Materials and Technology''. *64.3 g gelatin, Bloom strength of 210 *7.71 g ammonium dichromate *0.64 g chromium acetate *65 ml C₂H₅OH (ethanol) *Distilled water to make 1000 ml Plates are coated with the solution at 50°C by doctor-blade method to 20 µm. === 5&ndash;30&ndash;200, Ammonium Nitrate === Bahuguna, Beaulieu, and Arteaga, “Reflection display holograms on dichromated gelatin,” ''Applied Optics'', volume 31, issue 29 (1992). *2.5 g of ammonium dichromate *1.5 g of ammonium nitrate *100 ml of distilled water, heated to 70°C *15 gm of USP grade Baker's gelatin (125 bloom strength) powder slowly added while stirring Spin-coat at 100 rpm the still ~70°C emulsion for 90 seconds under hot-air gun. Dry vertically in a dark box. Plates are ready after about 6 hours. Sensitivity was reported as 100 mJ/cm² at 488 nm. [In Rallison’s Thick DCG paper, he associated ammonium nitrate with hardening.] === 4.5&ndash;30&ndash;500, Ammonia === Coblijn, Alexander B., "Theoretical background and practical processing techniques for art and technical work in dichromated gelatin holography", ''SPIE Institute Series'' Vol. IS 8 (1990). *100 g water *6 g gelatin *0.9 g ammonium dichromate *2 ml ammonia 35% (added last) Household ammonia is typically 5-10%. [Presumably, the ammonia inhibits the dark reaction.] 837126278de0a3be15ef3a9825259876b36adc70 0 836 1970 1725 2013-05-17T02:41:52Z Jsfisher 1 wikitext text/x-wiki Please note that these pages are currently in the process of being placed online. Some images and formatting from the original published version may still be missing. * [[Control of DCG and non silver holographic materials]] * [[Polarization properties of gelatin holograms]] * [[Blazed binary optics, from pc to plastic]] * [[Media characteristics, tables and plots]] (lots of images) * [[Recording Material Selection | Phase materials for HOE applications]] [[Category:Rallison]] 24bf666f0c9e3f34dd167b24b70c05f7cf0e68cf 0 810 1971 1603 2013-05-17T02:43:15Z Jsfisher 1 /* Blazed binary optics, from pc to plastic */ wikitext text/x-wiki Richard D. Rallison<br> Scott R. Schicker<br> RALCON CORP<br> Stephen E. Bialkowski, Ph.D.<br> Dept of Chem and Biochem<br> Utah State University<br> Logan, Utah 84322<br> == SUMMARY == A zone plate with 250 zones has been computed on a 386 machine and printed on 100 sheets of plain paper in a NEC LC890 printer. It was computed in Postscript language with 8 levels of grey in each zone and measured 75 inches in diameter before photoreduction to millimeter dimensions in a Nikon FA camera using Kodak 5052 TMX film. The reductions were made from 50 to 300 times to test the range of system resolution, fine grain Illford holographic film was substituted to test the camera MTF. Three micron layers of resist were used to get maximum phase shift and embossing masters of epoxy and nickel were made and evaluated. The final elements are embossed or cast in a variety of plastics and epoxies on glass, metal or semiconductor substrates. The final copies are efficient micro lenses and gratings useful for fabricating beam deflectors and a variety of stable optical interconnects. Resolutions are not as high as electron beam or laser scanning techniques but equipment and fabrication costs are low. We wrote a program named ZONE2 that will compute and print round or elliptical geometric zone plates with up to 20 shades of grey between zones. A second program named LINES writes linear gratings of the same sort, both generate postscript files that can be scaled as large as the computer system will handle. In our case the practicle upper limit was a 10 megabyte file that printed 250 zones times 8 shades of grey spread over 100 pages. The number of zones per page was found to be limited by the printer artifacts related to printer resolution and the computing of shades of grey in the postscript language. The number of grey shades is similarly limited to about 11 distinguishable shades in the inner zones and perhaps 6 to 8 shades in the outer zones. Geometric zone plates are free of aberrations only for f #s larger than 10 so the restriction to 250 zones means we are limited to a lens that is 10 mm in diameter with a focal length of 100 mm at a wavelength of 500 nm. If we had added a term and made the calculations for an interferometric zone plate we could have gone to an f# of 4 without aberrations using 250 zones in a diameter of 4 mm and a focal length of 16 mm. For some applications we could ignore the spherical aberrations of the geometric zone plate used at lower f #s and we made some in the f # 4 range for examination. Optics in this range require resolutions better than 250 l/mm at their outer limits. The camera was fitted with an f/2.8 Micro-NIKKOR 50mm lens which could reasonably resolve 4 micron details over a small angular field. The camera had to be loaded with individual frames of ILLFORD holographic film to insure a large enough film MTF, then each piece was hand processed in DEKTOL developer which yielded good grey scale. Shooting was done outside on a sunny day at distances of between 12 and 100 feet. The zone plate was cut and pieced together on an 8 by 7 foot substrate made from 2 inch thick urethane foam laminated to smooth white paneling. For maximum thickness we chose SHIPLEY #1400-37 PhotoResist spun onto 2.5 X 2.5 inch float glass squares for making the surface-relief copies of the Silver Halide masters. We had no previous experience with this material and this is what we found would work. 1) We set up a Gyrex IR oven with the low pre-heat on, the main heater control set to position seven, and the conveyer speed set to slowest. We washed the substrates, rinsed them in D.I. water, and dried them in a class 100 clean hood. When the substrates appeared dry,we ran them through the I.R. oven two or three times to dehydrate them and stored them in a clean hood until ready to coat. 2) The oven is then cooled down and set up for the "Soft Bake" step. The pre-heater is turned off, the heater is set to one,(130 to 140 degrees F) and the conveyer is set to its slowest speed ( 6 minutes). A soft bake for the photoresist is accomplished by running it through the oven only twice in succession. Over-baked resist does not react well to light. 3) We use a multiple discreet speed DC spin-coater with a small suction cup for applying the photoresist. The speed control is set to get approximately 900 revs per minute as measured by a mechanical tachometer. The spin coater box is lined with aluminum foil and set up on a class 100 clean bench. A substrate is centered on a suction cup and 3ml of the resist is applied to the substrate. The assembly is moved so as to spread the resist evenly over the surface to be coated. The suction cup is inserted into the spin-coater and spun for three minutes.This produced a dry 6 micron thick coating as measured by a .001 inch resolution dial indicator, ( 2.5 microns per division). 4) After a substrate is coated, immediately run it through the oven for the soft bake step. It is advisable to establish a routine so that residual solvents are uniformly distributed and sensitivity is then consistent and uniform across the substrate and from plate to plate. 5) To make a contact copy of a silver-halide master, we place the master with the emulsion side up onto the photoresist and weight the master down with a half inch thick slab of suprasil. Next we place a non-reflective mask over the suprasil to prevent edge scattering and reflections. Lastly, we expose the whole works to a standard 175 WATT mercury vapor yard light from which the outer glass globe has been removed to allow the full spectrum of UV to escape. Thirty minutes at a distance of one foot worked quite well for us and the lamp had to be fan cooled at that distance or it would melt the plastic. 6) The development process consists of washing the exposed photoresist off of the substrate with a dilute solution of MicroPosit 351 developer ( more commonly known as sodium hydroxide ). We used a solution of three parts water with one part of the MicroPosit 351 Developer Concentrate. Development is carried out in a small tank by uniformly immersing the plate and gently agitating only two times back and forth and then letting the plate lean against the side of the tank film side down. After developing the exposed resist for four minutes, we then rinsed it in a dilute solution of Kodak stop-bath ( 3 ml per 500 ml total volume ) and then De Ionized water for ten minutes. We tried using photo-flow in the rinse water but it left a residue. Dry the finished gratings in a clean hood under a gentle flow of air. DO NOT blow it dry with high pressure air, the grating is easily blown apart at this stage. 7) When we tried hard-baking the gratings in the Gyrex oven we succeeded in melting the resist. We now skip the hard-bake step as it does not seem to be necessary for electroplating or replicating with epoxy. We exported some resist masters to Dazzle Enterprizes for electro plating but we are preparing to do our own plating in the future. Electro plating is necessary to replicate with full depth onto substrates using UV epoxies or thin plastic films. We received 8 shims from two different resist masters made at 28 microns from Dazzle. The shims were made in 4 different thicknesses, 2, 4, 6, and 8 mils thick and were not as flat as we had hoped. Casting against them was carried out with UV epoxies and a nip roller with good results when using the 4 mil shims. Copies were also easily embossed into various plastics using a solvent and a Foster replicator. The Foster replicator is a hand cranked ringer, commonly used to ring out wet articles of clothing. '''''Last modified on 6/3/99<br>''''' [[Category:Rallison]] 4cda45ed01e6c1d8facbf6e4397de4e2c2e4b737 0 816 1972 1621 2013-05-17T02:48:09Z Jsfisher 1 wikitext text/x-wiki == ABSTRACT == We review the properties and relative usefulness of 3 non silver Volume holographic recording materials that are available today. Dichromated Gelatin (DCG) will receive the most attention followed by Dupont Omnidex products and a light treatment of Polyvinyl Carbazole (PVK). Enhancement and control of color, bandwidth and diffraction efficiency of volume reflection holograms recorded in DCG and photopolymers is discussed. Methods of increasing the bandwidth while shifting the center frequency toward the red is given for photopolymers. Red pseudo color will be covered thoroughly so that the practitioner will have all the elementary tools to make full color and broadband DCG holograms from scratch. The entire DCG technology is disclosed as it relates to production of high quality display holograms that span the spectrum and may be narrowband and very deep or shallow and broadband. == MATERIAL == The list of volume holographic recording materials includes the silver halide films, photopolymers, photocrosslinkers, photochromics, ferroelectric crystals and a few less well known oddities. While useful devices may be made in all these materials only a few will provide a holographer with a sufficiently high index modulation, resolution, signal to noise ratio, spectral response, and archival properties. The silver halide films have grain size limited resolution, scatter short wavelengths excessively, have only a moderate index modulation and tend to print out in UV light. They are popular for many applications because they can be made panchromatic, are much more sensitive than any other materials and are commercially available. We ocassionally use silver halide films to make master holograms and we reduce the blue scatter by converting them to a gelatin hologram (SHG). Used in this manner they are nearly equivalent to dichromated gelatin (DCG). They enable the production of DCG masters shot with red light at silver speeds that can be copied with green light in DCG and reconstructed finally at the original red color. SHG processes are covered in previous publications. The three materials detailed in this paper were chosen because they each have more or less all the properties needed for the construction of high quality or high efficiency broadband or narrowband color controlled holograms. They are not without faults however and the purpose of this work is to provide information to a holographer to assist him to make a better material choice for a particular task or to set up for production in DCG. Some information is given relating to the peculiar drop in average index in DCG, PVK and DMP128 due to the nature of the index modulation in these materials. Very thick coatings, up to about 50 microns are also dealt with in a special section. Comments made about preparation, processing, fine tuning, protection and applications are based on many years of working with DCG and many months of working with the other two materials, Dupont's Omnidex materials and Polyvinyl Carbazole (PVK). DMP 128 is another well documented material. It is a proprietary Polaroid formulation of lithium acrylate in combination with a branched polyethylenimine. Although it is not generally available commercially Polaroid has allowed laboratory evaluations and it is now quite common to get holograms mass produced in the material at Polaroid. Several other photopolymer systems are possibilities for holographic work but these 3 represent the readily available and practical recording materials of the day. == REFLECTION HOLOGRAM FABRICATION STEPS == === Mixing and coating === DCG is a mixture of Ammonium dichromate, gelatin and water. It is stirred together, heated, filtered and spun on or drawn down with a bar. Drying with or without heat from gel or liquid states makes little difference. Bright yellow lights are permissable. A 10 micron film can be made by mixing one gram dichromate with 3 grams of gelatin and 20 grams of water and spinning a flooded 8x10 glass plate at about 80 RPM. The solution and the coated plate is useful for about 3 days, much longer with refrigeration. PVK is dissolved in chlorobenzene along with Carbon tetraiodide, it is difficult to get into solution even with heat and agitation. It is also very unstable and may gel in as little as 15 minutes after mixing. The solution may be further thinned for convenient spinning but is easily applied with a bar. A number 28 bar will yield a 5 - 7 micron coating when 2 grams of PVK are dissolved in 25 grams of chlorobenzene. The patent disclosure mentions nothing about mixing the sensitizer with the PVK while still dry but if this is not done the solution will likely not be photosensitive. The solution will usually remain stable enough for coating for about 1 hour after mixing. The coated substrate is good for at least 8 hours. Dupont's materials can be purchased already to use on plastic substrates or may be obtained in liquid form for coating by any of the techniques covered here. === Storage after coating === DCG stores well at low humidity in a refrigerator or freezer but containers must prevent contamination, condensation, freezer burn and frost which can all destroy surface quality. Film of 10 to 20 microns or more store best and are good for at least a year. At room temperature and 50% RH, thin films are good for a few hours, thick films typically last a week or more. The addition of a small quantity of TMG to the mixture will greatly increase storage time at room temperature by increasing the PH. PVK does not store well as a rule, sometimes it has lasted a week in the refrigerator. Typically it moves suddenly to insensitivity within 24 hours and it does not seem to age gradually. The instabilities in coating and storing could be alleviated by adding more antioxidants to retard the spontaneous formation of free radicals but at the cost of reduced photo sensitivity. Dupont's materials seem to store well under refrigeration for a year or more depending on type, their newest film is also very sensitive, requiring only a few mj/cm*cm to expose in red or green. === Exposure characteristics === DCG is most sensitive in a hot moist environment. At 50% RH and 68 degrees F it may require 60 mj/cm*cm of 488 nm light, while at 75% RH and 80° F 4mJ/cm² will do the same job. At 441 nm less than 1 mJ is enough and at 514 or 532, 50 to 100 may be necessary. The percentage of dichromate affects speed more or less linearly, a 25% mixture is typical but mixtures of from 10 to 30 percent are necessary to control color. Gross overexposure will cause a decrease in efficiency all the way to zero. Overexposure causes an initial increase then a decrease in bandwidth and a blue shift plus a compression of contrast or dynamic range. PVK is totally insensitive to moisture, water can be used as an index matching fluid with no effect on the hologram. It requires about 20 mj/cm*cm at 488 nm to make a good single beam reflection hologram and because it is a cross linker it can be overexposed. Over exposure also results in a blue shift, a wider, then narrower bandwidth and loss of contrast. The Dupont material is a real time material and as a result can interfere with itself during an exposure. As the hologram is forming it is also reconstructing and making small dimensional changes. The results can be that at some time during an exposure the reconstruction could be out of phase with the construction momentarily. The energy required varies from about 8 mJ/cm² to a 100 or so mJ. It has good resistance to water and readable holograms have been made by us in 100ms. === Processing procedures === DCG is hardened briefly in Kodak Fixer with hardener then rinsed and plunged into several hot or cool alcohol baths. Cool baths produce better uniformity and lower noise, hot baths can yield tremendous index modulations with large chirps in Bragg spacing but often with increased noise. Depending on the mixtures, temperatures and times spent in each bath, a wide range of effects can be had. Processing and reprocessing affects bandwidth and center frequency over 100 nm or more and index modulation can be varied from near nothing to .25. If the first pass in the baths produces a shift to red, a second pass can shift it to blue and a 100 nm bandwidth can be reprocessed to yield a 30 nm bandwidth. Typically "master" holograms are processed to construct near the recording wavelength but processing and dichromate content allow the control of color to range from 650 to 450 nm for a straight on exposure at 488 nm. This much versatility in color control is certainly useful and will be covered in more detail. Conformal mirrors on flat substrates can be color shifted easily with angle but more complex shapes must be tuned with processing and film formula juggling. As an example of a reprocessing procedure, a red shifted broadband mirror may be narrowed and blue shifted by agitation for 30 seconds in a room temp 50:50 mixture of water and alcohol then plunged into 99% hot alcohol with agitation for 30 seconds and pulled slowly from the hot bath. The direction of the shift can be controlled by the ratio of alcohol and water in the first bath and the amount of shift can be controlled by the time in the same bath. A near ideal tuning bath has a specific gravity of .86 when it is warmed to about 55 degrees C. This process can be repeated many times if necessary, especially if the last hot bath is not hot enough to cause excessive scattering center buildup. Multiple buffer baths between the first color control bath and the last dehydration bath help to keep the last bath clean. PVK is swollen in Xylene or Toluene for a few seconds then dried in warm Hexanes or Hexanes mixed with alcohols. Like DCG the latent image must be enhanced by swelling in the first solvent and then replacing that solvent with a miscible but nonswelling solvent. Again, color and modulation control is by temperature and time. Color control is similar to DCG methods and either broadband red shifts or narrowband blue shifts are possible by altering time and temperature. Reprocessing is possible but scattering centers build up rather quickly in this material. The first solvent probably dissolves away material as it causes swelling. Signal to noise is usually good in narrow band processing but not so good for broadband reconstructions. A recent proprietary improvement in processing involves the use of a clever monobath made up of two miscible solvents. One of the solvents will swell the PVK and is more volatile than the other solvent which will not soften or swell the PVK. The most volatile solvent evaporates first and leaves the hologram structure in rigid uniform shape while the second solvent is driven out with warm dry air. Dupont films are developed with UV light and heat. They may then be brightened and color shifted by the addition of monomers and or solvents. It is common practice to laminate a cover glass over gelatin holograms to protect them from moisture, abrasion and chemicals. Many common epoxies have been identified as safe for this purpose as well as a broad class of adhesives described as UV polymerizable substances,( monomers, epoxies, resins, adhesives, etc). I accidentally caused an enhancement of several photopolymer holograms while attempting to laminate them. In one case the bandwidth widened from 40 nm to 150 nm and the optical density remained almost as high as the original structure. The photopolymers behave a little like sponges that can be dampened and swollen or alternatively soaked and saturated while the shock dried DCG and PVK structures are more like a stack of Ruffles potato chips that get damp, go limp and then collapse. Enhancement of Dupont photopolymer is the easiest and most reliable. The holograms produced from blue exposures originally playback blue but the enhanced holograms playback at a longer wavelength and are noticeably brighter. Solvents alone brighten and shift the reconstructions to the red but they are temporary treatments and not generally as effective as UV curable monomer type adhesives. A Dupont product is now available to make predictable shifts in playback color. They provide a monomer on a cover sheet that will diffuse into the exposed film where it causes swelling and can then be fixed by polymerization under a UV source. Some Dupont film reflection holograms will respond to the following recipe with a red shift and increase in total diffracted energy. Apply Lightweld 401 evenly and cover then wait for a color change and cure with strong UV source. If this substance is left uncured it may destroy the original structure. It is also anaerobic and therefore requires a cover to cure. === Protection === DCG is notoriously bad at remaining stable in normal environments. Moisture will cause the Bragg structure to collapse and the gelatin grabs moisture easily from the air right through most plastics and glue. This material usually requires lamination between glass with enough gelatin removed around the edges to form an "O" ring seal. Thick plastics, such as 30 mil mylar, will also work and certain fluorinated plastics such as "Aclar" in thin 5 mill layers are satisfactory provided that the edges have been cleared of gelatin before laminating. PVK needs protection from abrasion but it stands alone as the only holographic material we ever worked with that is completely waterproof. It requires only a 4 mil mylar laminate for adequate abrasion protection from the environment. Dupont's materials may be used as is or uncovered and rolled down onto a glass substrate. They need very little protection after being fully polymerized with UV light but a stiff flat backing helps with image distortion. Water can affect them temporarily but the structure is essentially humidity proof. == APPLICATION NOTES == DCG is easily the most versatile material, just about any kind of HOE or hologram can be made in it. Unfortunately it has poor environmental stability and must be well protected or it may not be intact when you need it. As long as glass or thick plastic is acceptable in the finished product DCG is the number one choice. With some difficulty it can be made panchromatic for full color work and under warm moist conditions it is a little more sensitive than the other two in the blue-green region. The SHG versions are much more sensitive and represent the only fast "non silver" medium useful for pulse holography applications. PVK is not so pleasant to work with as DCG but it goes onto plastic substrates easily, has a high delta n and needs only minimal protection. It should be very good for such things as eyewear, solar collection and other outdoor applications or anyplace where superb environmental stability is required. Dupont's materials come with an ever wider range of properties. They are durable and panchromatic but lack a little in dynamic range. The maximum available index modulation is lower than the other two materials and display holograms are typically less bright. Initially we tried to determine the index modulation of simple reflectors made in each material by fitting them to the simple one dimensional Kogelnick expression for diffraction efficiency (D.E.) of reflection volume holograms. {| border="1" |- ! colspan="2" | Kogelnick Expression |- | <math> DE = \tanh^2 \, {{\pi\Delta n T} \over {\lambda\sin\Theta}} </math> | Where *T = thickness of material in microns *λ = .5 microns (typical) *sin θ = 1 (for conformal mirror) |} This relationship seldom describes real reflection structures because it does not describe the effects of a gradient on the index modulation (delta n) or a chirp in the grating spacing (d). A gradient in delta n such as is caused by the absorption of light by the sensitizing dye results in a smooth broadening of the angular and spectral bandwidths and a smoothing of sideband peaks (when DE is held constant.) A chirp in the Bragg plane spacing also broadens the bandwidth though not so smoothly and the combination produces a highly asymmetric spectral bandwidth. The data and a description of the computer model is given in a previous publication. All three materials exhibit a useful range of index modulation and color control and each has found multiple commercial uses. The differences lie mainly in sensitometric characteristics, environmental stability and in the degree of difficulty to obtain or use. The balance of this paper will detail the use of DCG. We will try to give instructions that can be followed by anyone that is already familiar with more conventional holographic fabrication techniques and materials. Some details are left out for the sake of brevity but can be found elsewhere in the references or other literature. == SPIN COATING APPARATUS == A variable speed turntable capable of 50 to 100 RPM will coat films of gelatin or PVK from 4 to 50 microns on 8 x 10 inch glass or plastic substrates. Plates as small as 3 inch diameter or as large as 16 x 16 inches have also been successfully coated with this range and technique. The turntable should be equipped with a surface or arms that will mate to a removable tray that is one or two inches larger than the substrates being coated. We have used ordinary variable speed phonograph players with pie tins turned upside down and glued to the turntables and we have used Dayton variable speed gear motors with heavy duty arms attached. Both devices worked very well. Trays have been made up of stainless steel, plexiglass, polyethylene dishpans or modified from aluminum cake and pizza pans. The best trays have straight sides measuring 2 1/2 to 4 inches high and are fitted with 3 rubber posts inside and outside. The posts inside hold the substrate an inch or so off the bottom of the tray and the outside posts serve to level the tray during pouring of solutions and to center the tray during spinning. The spinning tray and substrate may generate useful turbulence that aids in drying and distributing the solution. Excess solution is caught in the tray and emptied between substrates then is easily soaked clean in hot water after a days activities. An important component that augments drying and uniformity is the blower-heater. It hangs off center and above the whirling tray. Turbulence and heat combine to make uniform coatings in about five minutes. We recommend the use of a variable temperature 600 watt blower such as might be found in the ceilings of some bathrooms. A little experimenting with angle and position will quickly determine the best place to hang this unit in your clean hood or bench area. Coat and examine uniformity by looking for local fringe patterns under a fluorescent lamp or better yet a fluorescent long wave black light. == BAR COATING APPARATUS == Lab coating bars are available from R.D. Specialty Co. in Webster N.Y. Ph (716)265-0220. A selection of bar types may be purchased for about $ 50.00. We have used bars of 3/8" diameter wound with # 24 wire as a standard but we have other windings and diameters on hand for special applications and recommend you do the same. These bars are also useful for applying strippable coatings for anti halo backings, and have been used for coating photopolymers and protective epoxy layers etc. Jigging for bar coating can be as simple as a clipboard with lint free paper placed under the substrate. A better jig is one that holds the plate above a trough that can catch run-off. The whole thing can be plexiglass which is particularly easy to get gelatin off of and it also preferentially over glass attracts dust particles. Bar or spin coating is done in a class 100 environment and is accomplished by pouring out a line of solution and pulling it down with a uniform pressure and velocity. A little practice will determine correct amount of solution, speed and pressure. The bar is not rotated as it is pulled and a new location or freshly cleaned and dried bar is used on each new substrate. Variations in thickness may be accomplished by changing wire size or viscosity or both. Precautions must be taken to keep the bars clean and undamaged. We place used bars in warm water and rinse and dry them before each use. A rack that holds them suspended above any surfaces is useful for storage, cleaning and serial use. It can be made from plastics or metals. Coated plates need to be placed in a level position where they can air dry in a few minutes. The coating jig should be nominally level. Cronar, (polyester) substrates are easily coated with these bars. Cronar is a Dupont product. One source is Farrest Chemical &amp; Supply, 680 Toland St., San Francisco, CA (415)8241400. It is available in sheets (C-42) or rolls (C-41) in a variety of sizes. Exposure of Cronar is done with a thick glass vacuum chuck or by humidifying the gelatin and rolling it against a clean glass plate. It is optically active and you may need to identify its neutral optical axis before exposure. Processing is best done by stretching it in a frame for dipping and agitation or by clipping it flush to a glass substrate fitted with a handle on one side. == FILM PREPARATION == Many factors need to be considered when mixing DCG for holographic film. === Jelly strength === The jelly strength, measured with the Bloom Gelometer, is an important consideration. The current gelatin being used by us for film production is either MCB brand (Mattheson, Coleman, and Bell Manufacturing Chemists, Norwood, OH 45212 # GX-45' OH 45212) # GX-45. Grayslake Type B USP XXIII Box 248 Grayslake,IL . 60030 Phone (312) 223-8141 Contact Bob Buscher. Both gelatins have bloom strengths from 215-235. Comparable with the jelly strength is the rated solubility of the gelatin, and the mode of manufacturing. (Acid or Alkaline processed.) These can each make a considerable difference in the quality for each lot. It is best to test every specific lot before final acceptance of a gelatin. Perhaps the best rating for gelatin to be used for DCG is the jelly strength-to-viscosity ratio. A ratio of at least 4 or 5 to 1 is considered good. Our current batch has a bloom of 232 grams, a viscosity of 42 mps and a ph of 5.1. === Heating === One important caution when preparing the DCG film mixture is the destabilization of the gelatin at high temperature. When heated for an excessive period of time, the film breaks up, causing what we term as film "pits" in the final emulsion. These "pits" have the appearance of small circles of various sizes and scatter themselves throughout the plate. When the film is processed, the final image has small voids where the "pits" were. So far, the length of the heating time and the peak temperature that cause this have not been determined. In the past, temperature and heating time causing this have fluctuated. But the safe method is to heat the film mixture at the shortest possible heating time to dissolve the gelatin content completely. 130 F to 150 F (60 C.) is usually a high enough temperature to dissolve without cooking. Gelatin "melts" around 40 to 45 C. The causes of film "pitting" are still unknown to us as well as what the "pits" really are. But their characteristics (and that of gelatin) can give us some ideas. It is important to take all known preventative measures for keeping them off the emulsion. Triple filtering helps and avoiding hot spots while mixing helps. We use a standard mag stir hot plate and glass flasks which are heated slowly while stirring or heated in a water bath, a microwave oven has also worked well using plastic bottles . Film "pitting", or destabilization, in the past, has seemed to be affected by the solubility of the gelatin. The higher the solubility, the less likely film "pits" occurred. The solubility, of course, is slightly affected by jelly strength and impurities. Literature within the gelatin film industry indicates temperature separation may occur, partly due to the polysaccharide content of the gelatin. There is one speculation of film pits which involves the crystallinity function in drying films. (And this is a function of film temperature.) The other theory for film "pits" is the presence of insoluble impurities (such as arsenic, grease, etc.) on the surface of the film. These substances probably conglomerate during mixing and heating to make larger hydrophobic areas on the glass. Surfactants would alleviate this but they aggravate adhesion problems as well. === Water === Use deionized water for the DCG film mixture. It eliminates certain salts which have produced inconsistencies in film behavior. Distilled water is also acceptable. Any water should be funnel filtered through a 5 micron or smaller filter and be free of oil, grease, and bacteria that thrive on gelatin. === Storage === Film mixtures may be stored in a refrigerator for a week or two and reheated in water or a microwave oven as needed. When stored longer the become less and less likely to flow when warmed. === Film codes === The film mixtures vary in dichromate and gelatin percentages. The variations depend on the specific use that a DCG film plate has. The film code currently used contains three numbers. The first being the gram-weight of the ammonium dichromate, the second being the gram-weight of the gelatin, and the third being the gram-weight (mls) of the water to be used in the film mixture. (Usually mixed in a 500 ml poly bottle.) The code for film used in broadband image holograms is 8-30-350. Thus, 8 grams dichromate, 30 grams gelatine, and 350 grams (mls) of water are mixed together. The mixture code for "red" holograms is 3-30-200. Most holographic optics are made in 10-30-250 to 8-30-150. Very thick coatings of 30 to 50 microns can be made using a 3-30-125 mixture but special fixturing may have to be made to get the gelatin to flow uniformly and the dried film may come off the substrate unless it is baked on at high humidity. We find adhesion is enhanced by cleaning the substrate in clorox and then baking the coated plate at 130 degree F in the presense of water at saturation. In using the film code for a variety of mixtures, the 30-gram gelatin weight number always remains constant. Thus, when a thicker emulsion is desired, the water number decreases. And when more absorption is desired, the dichromate number increases, an increase in thickness narrows the bandwidth and an increase in dichromate shifts the color toward the blue. As a general rule, thicker emulsions require longer process times but are easier to make uniform. The dichromate concentration determines light absorption and the center reconstruction wavelength of the hologram. For higher dichromate concentrations, the increased absorption produces larger gradients of index modulation. Lower the dichromate concentrations produce more uniform index modulations. Larger gradients yield slightly larger bandwidths and the removal of higher percentages of dichromate during processing results in thinner and thus bluer holograms. When a specific bandwidth is desired, along with a specific reconstruction wavelength; it is best to experiment with various film mixtures. Usually starting with a standard mixture and then adjusting the thickness, and dichromate content to achieve the desired results. The color controllability and uniformity of DCG film improves with thicker film emulsions. Consequently, they are more forgiving in their exposing and developing parameters. Extremely thick (25 micron or more) emulsions ( X-30-150, a 5 to 1 water-to-gel ratio) are difficult to use. They are prone to excess bubbles, pre-mature jelling, film pits, low viscous flow, increased impurities and during processing sometimes pull up off the substrate if not annealed in a wet oven. Processing of these thick films is often done with room temperature baths, or slightly elavated temperatures, over several minutes in each bath. === Sensitizer === We use ammonium dichromate crystals or for redder reds Potassium dichromate but the most sensitive of the dichromates is Pyridine dichromate. We don't use it because of it's shorter life and difficult preparation. The addition of ammonium nitrate can make the dichromate several times more sensitive, but decreases the useful life and blue shifts the image. Approximate ammonium nitrate concentrations are usually in a ratio of 1 to 5 by weight to ammonium dichromate up to a maximum of 1 to 1. When the additional substance is washed out of the gelatin a net shrinkage occurs which amounts to a blue shift in reflection holograms and lays down Bragg planes in transmission holograms. === Filtering === At a minimum, filter the heated mixture through two coffee filters (Mr. Coffee) for a standard 8-30-350 film. For 6-30-200 and thicker emulsions, use one coffee filter. Run the filtered mix into the pouring container. When necessary, a finer grade lab filter may be used, we have forced warm gelatin through a 1 micron filter using a gear pump and also using a peristaltic pump. The use of a peristaltic pump makes metering and filtering possible at the same time. A simple syringe with a 2 micron filter is very effective and may double as a way to meter out a fixed amount onto a plate. === Applicator === The pouring container (with the film) is kept on an electric warming plate. The temperature of the plate should be carefully controlled to provide only enough warmth to prevent jelling (50-60 degrees C). We like to use a lab hot plate and water bath, the pouring container is a tea pot like bottle modified from a lab wash bottle. Any poly bottle that empties from the bottom will do. Some custom shaping of the "spout" may be necessary to prevent the formation of bubbles. == COATING TECHNIQUES == The coating station consists of a class 100 cleanhood or laminar flow bench, a dryer-heater unit and the turntable. The clean hood should be large enough to fit the turntable and two plate racks inside. (About 2 1/2' x 3 1/2' or larger.) A yellow safelight may also be mounted inside. Air flow should be 200 cfm or higher for this size hood. === Cleaning glass === There is a bit of an art to coating and it takes a little practice to become good at it. The first step is to prepare the plates by soaking over night in a soapy solution that contains some chlorine. The plates also need scrubbing and a rinse in deionized water. The final rinse should be done in or in front of the clean hood used for drying the plates. The chlorine soak has been found to aid in adhesion of the gel to the glass. The glass may be soda lime plate or float glass or any most any other kind but it has to be thick enough to withstand the shrinking forces generated during exposure. This means that it should be double strength or thicker(3 to 6 mm) for 8 x 10 shots, single strength (2 to 3 mm) for 4 x 5 and 5 x 7, and may be picture glass or as thin as 1 mm for 2 x 2 exposures. === Coating glass === The gelatin is poured over the dried plate in such a way that no gel spills off the edge and no bubbles are formed. This is accomplished by pouring a large puddle and gently rocking the tray till all edges are wet. The turntable is then turned on with the blower/heater for about 5 minutes. If the plate was uniformly wet and had no contaminants then the coating is likely to be uniform using these techniques. The range of RPM we found useful runs from 65 to 100, speeds outside this range failed to be uniform. Start with a rotation speed of about 80 RPM and position the heater-blower about 6 inches above and to one side of center of the coating tray. For 8 by 10 plates this offset is about 3 inches. The fine tuning of the position of the blower will greatly improve the uniformity of your coatings. === Ageing and thickness === The film is ready for exposure after it has been aged an hour or so for a 350 mixture or a day later for a 150 mixture. The addition of 1 or 2 ml of TMG will extend the useful room temp life of 350 film to a day or two and will make 150 film last for several weeks in a 21 degree C, 50% RH environment. The thicknesses of the commonly used mixtures after spinning at 80 RPM and after processing are as follows: 350 yields 5-6 microns, 250 yields 8-9 microns, 200 yields 10-12 microns, 150 yields 20-24 microns and 125 yields 25 to 50 microns depending on speed. === Bandwidths and color === The relative bandwidths run from 50 to 150 nm for 350 film, depending on processing used. 250 and 200 film make 10 to 50 nm bandwidths depending on processing and 150 film can get down to 8 nm but also runs as high as 30 nm. Very thick film can have bandwidths of less than 8 nm. The color of a film made from a 3-30-200 mixture is around 630 nm when shot at 514 nm. The color of 6- 30 film is around 590 for a 514 shot and a 10-30 mixture will easily be tuned to play back at the same wavelength it was shot at. Methods of planning and controlling color in display holograms are discussed below, similar but more precise methods are used for HOEs. == COLOR DICHROMATE OBJECT PREPARATION == The two color method produces rich red-orange and bright clean blue-green colors that mix to a creamy white. Color coding of the object is optional but helpful in most cases and production is done from two masters in two different films. The three color system requires color coding for red at the mastering stage but no coding for blue or green, which are mastered first. Both systems are part natural, part pseudo color and require only two laser lines and two film formulations. Blue is obtained naturally by using the 458 argon line and green or red are derived from the 514 line. In production the two color system is identical to current master/copy methods in that batches are shot at 458 or at 514 and later registered and laminated together. The three color system requires blue and green exposures in the same emulsion and red in a second batch. The laser must then be operated multiline or be switched constantly or a second laser introduced. The preferred method is multiline operation with independent shuttering except that max power in each line is reduced because several lines compete for available energy. The two color, two plate system makes very satisfying flesh tones and color balance is fairly easy to maintain because it can be done by mixing and matching batches and or individual holograms at the laminating stage. The two color single plate method has the obvious advantage of no registration problems but it has a limited color range because there are only 56 nm between 458 and 514nm. === Object preparation === Blue-green areas should be overcoated lightly with a bright blue pigment such as Liquitex Brilliant Blue #20002-381 or Pelikan Deep Blue #39. This will effectively inhibit refection at 514. The red-orange areas must be touched up with yellow pigment such as Liquitex #1002-411 or Pelikan Yellow #10 both of which absorb 458 but reflect 514. At this stage H1 masters or correctly colored copies can be made, the Blue-Green master may be made to reconstruct at 488 so that production copies can be done using only 488 and 514. The 514 exposure is done with the film side facing the reference beam and the 458 exposure is done the other way around with a spacer between the object and film having the same optical thickness as the 514 substrate. === Film preparations === A good blue or green production film can be made by mixing the 8-30-250 formulae with or without a ml of TMG. A good red or yellow film is made by reducing the amount of dichromate to 2 or 3 grams. The plates are ready to use after standing at room temp for an hour and they may be stored in a refrigerator for months on end. Better results may be obtained from some softer gelatins by ageing films for a few days. === Exposure procedures === Blue holograms may be made by exposing in a Denisyuk fashion @ 458, 441, 476 nm or some other line bluer than 488. The energy required is about 20 mj/cm*cm and it helps to do it with the reference at 50 degrees from the normal and with the E vector perpendicular to the plate to reduce noise from mirroring. Green holograms may be similarly produced by using the 514 line, again near Brewster's angle. This time it may pay to try 55 degrees because absorption is much lower @ 514 so "Newton's wood" type noise is more likely to show up.The energy required is about 90 mj/cm*cm. Red holograms result from using the red film formula and exposing @ 514 close to Brewster's angle. The fringe structure is expanded to red or yellow reconstruction because less material is washed out during development. If the master has been made in SHG using a HeNe then this copy will be a correct color reproduction. === Processing procedures === The film of gelatin is about 8 or 9 microns thick and requires much longer processing times than 4 or 5 micron broadband films. Development takes 3 to 5 minutes in kodak fixer, followed by a 1 minute rinse in tap water. Dehydration is done in warm isopropyl alcohol (48 to 55 degrees C) using at least 2 baths after the tuning bath and agitating mildly in each for about 30 seconds. Drying is most easily done by removing the plate very slowly from the last and driest bath. If it does not look uniform try soaking in warm water for 10 minutes and then dehydrate with more agitation. Fine tuning of the color may be done by soaking in the tuning bath. This is the way that we get the center reconstruction frequency to match the copy wavelength. Start with a master that is a little too red and gradually tune it to the correct color by repeated passes through the tuning bath and the last hot dry bath. 350, 250, and even 200 mixtures all respond to this method. A hydrometer is necessary to monitor the specific gravity of the tuning bath and maintain it at or near .86. Processing 350 film for masters is done this way but the same film can be processed for broadband reconstruction by using a shorter development time and skipping the tuning bath. Experimenting is the only way to get the desired results. Some guides to broadband techniques can be found in the proceedings of the first Lake Forest symposium in 1982. An alternative to multiple bath processing has been proposed by workers at IBM. They suggest that for thin films, on the order of our 350 or 400 mixtures, spinning the plate while spraying a series of fluids works best. Thin films are not easy to process in baths because of the fast diffusion of solvents in and out of the rather porous gelatin. In the IBM method, all of the regular baths are sprayed progressively for only a few seconds each onto the spinning plate. They felt that the spray system would be a superior way to automate processing techniques, we experimented with spraying many years ago but did not have the success that IBM has had. == Hazards == Dichromate powder is dangerous if inhaled and the liquid mixture may irritate some people if left on the skin. Dust masks and rubber gloves are therefore recommended whenever film is being made. Isopropyl alcohol has low toxicity but is quite flammable and must always be heated in a safe manner such as in a water bath. Alcohol fires may be extinguished with water, dry chemical, Halon or CO2. Glass must be handled carefully and whenever possible the edges should be ground before handling. == REFERENCES == These references are all by the same author and may be useful to the holographer that tries to apply the methods detailed in this paper. A design guide and brochure for HOE's is available on request. A video tape demonstrating this technology is also conditionally available from the author. *"Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)." S.P.I.E. Proceedings, Volume 212, pp. 22, 1979 *"Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College Holography Workshop and First International Symposium on Display Holography, July 1982. Lake Forest, IL. *"Practical Polymers for Holography", Second International Symposium on Display Holography, Lake Forest College, IL. *"Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug. 1987. *"Alternative Volume Recording Media, A Qualitative Comparison" Third International Symposium on Display Holography, Lake Forest College, IL 1988 *"Survey of properties of volume holographic materials", SPIE vol. 1051, Practicle Holography III, 1989 p. 68 - LA, CA. *"Novel Enhancement of Photopolymers", SPIE vol 1212, Practical Holography IV, 1990 LA, CA. '''''Last modified on 4/8/99''''' [[Category:Rallison]] 139c940c04ee86a16657b960143e67a94173f434 1973 1972 2013-05-17T02:49:33Z Jsfisher 1 /* Hazards */ wikitext text/x-wiki == ABSTRACT == We review the properties and relative usefulness of 3 non silver Volume holographic recording materials that are available today. Dichromated Gelatin (DCG) will receive the most attention followed by Dupont Omnidex products and a light treatment of Polyvinyl Carbazole (PVK). Enhancement and control of color, bandwidth and diffraction efficiency of volume reflection holograms recorded in DCG and photopolymers is discussed. Methods of increasing the bandwidth while shifting the center frequency toward the red is given for photopolymers. Red pseudo color will be covered thoroughly so that the practitioner will have all the elementary tools to make full color and broadband DCG holograms from scratch. The entire DCG technology is disclosed as it relates to production of high quality display holograms that span the spectrum and may be narrowband and very deep or shallow and broadband. == MATERIAL == The list of volume holographic recording materials includes the silver halide films, photopolymers, photocrosslinkers, photochromics, ferroelectric crystals and a few less well known oddities. While useful devices may be made in all these materials only a few will provide a holographer with a sufficiently high index modulation, resolution, signal to noise ratio, spectral response, and archival properties. The silver halide films have grain size limited resolution, scatter short wavelengths excessively, have only a moderate index modulation and tend to print out in UV light. They are popular for many applications because they can be made panchromatic, are much more sensitive than any other materials and are commercially available. We ocassionally use silver halide films to make master holograms and we reduce the blue scatter by converting them to a gelatin hologram (SHG). Used in this manner they are nearly equivalent to dichromated gelatin (DCG). They enable the production of DCG masters shot with red light at silver speeds that can be copied with green light in DCG and reconstructed finally at the original red color. SHG processes are covered in previous publications. The three materials detailed in this paper were chosen because they each have more or less all the properties needed for the construction of high quality or high efficiency broadband or narrowband color controlled holograms. They are not without faults however and the purpose of this work is to provide information to a holographer to assist him to make a better material choice for a particular task or to set up for production in DCG. Some information is given relating to the peculiar drop in average index in DCG, PVK and DMP128 due to the nature of the index modulation in these materials. Very thick coatings, up to about 50 microns are also dealt with in a special section. Comments made about preparation, processing, fine tuning, protection and applications are based on many years of working with DCG and many months of working with the other two materials, Dupont's Omnidex materials and Polyvinyl Carbazole (PVK). DMP 128 is another well documented material. It is a proprietary Polaroid formulation of lithium acrylate in combination with a branched polyethylenimine. Although it is not generally available commercially Polaroid has allowed laboratory evaluations and it is now quite common to get holograms mass produced in the material at Polaroid. Several other photopolymer systems are possibilities for holographic work but these 3 represent the readily available and practical recording materials of the day. == REFLECTION HOLOGRAM FABRICATION STEPS == === Mixing and coating === DCG is a mixture of Ammonium dichromate, gelatin and water. It is stirred together, heated, filtered and spun on or drawn down with a bar. Drying with or without heat from gel or liquid states makes little difference. Bright yellow lights are permissable. A 10 micron film can be made by mixing one gram dichromate with 3 grams of gelatin and 20 grams of water and spinning a flooded 8x10 glass plate at about 80 RPM. The solution and the coated plate is useful for about 3 days, much longer with refrigeration. PVK is dissolved in chlorobenzene along with Carbon tetraiodide, it is difficult to get into solution even with heat and agitation. It is also very unstable and may gel in as little as 15 minutes after mixing. The solution may be further thinned for convenient spinning but is easily applied with a bar. A number 28 bar will yield a 5 - 7 micron coating when 2 grams of PVK are dissolved in 25 grams of chlorobenzene. The patent disclosure mentions nothing about mixing the sensitizer with the PVK while still dry but if this is not done the solution will likely not be photosensitive. The solution will usually remain stable enough for coating for about 1 hour after mixing. The coated substrate is good for at least 8 hours. Dupont's materials can be purchased already to use on plastic substrates or may be obtained in liquid form for coating by any of the techniques covered here. === Storage after coating === DCG stores well at low humidity in a refrigerator or freezer but containers must prevent contamination, condensation, freezer burn and frost which can all destroy surface quality. Film of 10 to 20 microns or more store best and are good for at least a year. At room temperature and 50% RH, thin films are good for a few hours, thick films typically last a week or more. The addition of a small quantity of TMG to the mixture will greatly increase storage time at room temperature by increasing the PH. PVK does not store well as a rule, sometimes it has lasted a week in the refrigerator. Typically it moves suddenly to insensitivity within 24 hours and it does not seem to age gradually. The instabilities in coating and storing could be alleviated by adding more antioxidants to retard the spontaneous formation of free radicals but at the cost of reduced photo sensitivity. Dupont's materials seem to store well under refrigeration for a year or more depending on type, their newest film is also very sensitive, requiring only a few mj/cm*cm to expose in red or green. === Exposure characteristics === DCG is most sensitive in a hot moist environment. At 50% RH and 68 degrees F it may require 60 mj/cm*cm of 488 nm light, while at 75% RH and 80° F 4mJ/cm² will do the same job. At 441 nm less than 1 mJ is enough and at 514 or 532, 50 to 100 may be necessary. The percentage of dichromate affects speed more or less linearly, a 25% mixture is typical but mixtures of from 10 to 30 percent are necessary to control color. Gross overexposure will cause a decrease in efficiency all the way to zero. Overexposure causes an initial increase then a decrease in bandwidth and a blue shift plus a compression of contrast or dynamic range. PVK is totally insensitive to moisture, water can be used as an index matching fluid with no effect on the hologram. It requires about 20 mj/cm*cm at 488 nm to make a good single beam reflection hologram and because it is a cross linker it can be overexposed. Over exposure also results in a blue shift, a wider, then narrower bandwidth and loss of contrast. The Dupont material is a real time material and as a result can interfere with itself during an exposure. As the hologram is forming it is also reconstructing and making small dimensional changes. The results can be that at some time during an exposure the reconstruction could be out of phase with the construction momentarily. The energy required varies from about 8 mJ/cm² to a 100 or so mJ. It has good resistance to water and readable holograms have been made by us in 100ms. === Processing procedures === DCG is hardened briefly in Kodak Fixer with hardener then rinsed and plunged into several hot or cool alcohol baths. Cool baths produce better uniformity and lower noise, hot baths can yield tremendous index modulations with large chirps in Bragg spacing but often with increased noise. Depending on the mixtures, temperatures and times spent in each bath, a wide range of effects can be had. Processing and reprocessing affects bandwidth and center frequency over 100 nm or more and index modulation can be varied from near nothing to .25. If the first pass in the baths produces a shift to red, a second pass can shift it to blue and a 100 nm bandwidth can be reprocessed to yield a 30 nm bandwidth. Typically "master" holograms are processed to construct near the recording wavelength but processing and dichromate content allow the control of color to range from 650 to 450 nm for a straight on exposure at 488 nm. This much versatility in color control is certainly useful and will be covered in more detail. Conformal mirrors on flat substrates can be color shifted easily with angle but more complex shapes must be tuned with processing and film formula juggling. As an example of a reprocessing procedure, a red shifted broadband mirror may be narrowed and blue shifted by agitation for 30 seconds in a room temp 50:50 mixture of water and alcohol then plunged into 99% hot alcohol with agitation for 30 seconds and pulled slowly from the hot bath. The direction of the shift can be controlled by the ratio of alcohol and water in the first bath and the amount of shift can be controlled by the time in the same bath. A near ideal tuning bath has a specific gravity of .86 when it is warmed to about 55 degrees C. This process can be repeated many times if necessary, especially if the last hot bath is not hot enough to cause excessive scattering center buildup. Multiple buffer baths between the first color control bath and the last dehydration bath help to keep the last bath clean. PVK is swollen in Xylene or Toluene for a few seconds then dried in warm Hexanes or Hexanes mixed with alcohols. Like DCG the latent image must be enhanced by swelling in the first solvent and then replacing that solvent with a miscible but nonswelling solvent. Again, color and modulation control is by temperature and time. Color control is similar to DCG methods and either broadband red shifts or narrowband blue shifts are possible by altering time and temperature. Reprocessing is possible but scattering centers build up rather quickly in this material. The first solvent probably dissolves away material as it causes swelling. Signal to noise is usually good in narrow band processing but not so good for broadband reconstructions. A recent proprietary improvement in processing involves the use of a clever monobath made up of two miscible solvents. One of the solvents will swell the PVK and is more volatile than the other solvent which will not soften or swell the PVK. The most volatile solvent evaporates first and leaves the hologram structure in rigid uniform shape while the second solvent is driven out with warm dry air. Dupont films are developed with UV light and heat. They may then be brightened and color shifted by the addition of monomers and or solvents. It is common practice to laminate a cover glass over gelatin holograms to protect them from moisture, abrasion and chemicals. Many common epoxies have been identified as safe for this purpose as well as a broad class of adhesives described as UV polymerizable substances,( monomers, epoxies, resins, adhesives, etc). I accidentally caused an enhancement of several photopolymer holograms while attempting to laminate them. In one case the bandwidth widened from 40 nm to 150 nm and the optical density remained almost as high as the original structure. The photopolymers behave a little like sponges that can be dampened and swollen or alternatively soaked and saturated while the shock dried DCG and PVK structures are more like a stack of Ruffles potato chips that get damp, go limp and then collapse. Enhancement of Dupont photopolymer is the easiest and most reliable. The holograms produced from blue exposures originally playback blue but the enhanced holograms playback at a longer wavelength and are noticeably brighter. Solvents alone brighten and shift the reconstructions to the red but they are temporary treatments and not generally as effective as UV curable monomer type adhesives. A Dupont product is now available to make predictable shifts in playback color. They provide a monomer on a cover sheet that will diffuse into the exposed film where it causes swelling and can then be fixed by polymerization under a UV source. Some Dupont film reflection holograms will respond to the following recipe with a red shift and increase in total diffracted energy. Apply Lightweld 401 evenly and cover then wait for a color change and cure with strong UV source. If this substance is left uncured it may destroy the original structure. It is also anaerobic and therefore requires a cover to cure. === Protection === DCG is notoriously bad at remaining stable in normal environments. Moisture will cause the Bragg structure to collapse and the gelatin grabs moisture easily from the air right through most plastics and glue. This material usually requires lamination between glass with enough gelatin removed around the edges to form an "O" ring seal. Thick plastics, such as 30 mil mylar, will also work and certain fluorinated plastics such as "Aclar" in thin 5 mill layers are satisfactory provided that the edges have been cleared of gelatin before laminating. PVK needs protection from abrasion but it stands alone as the only holographic material we ever worked with that is completely waterproof. It requires only a 4 mil mylar laminate for adequate abrasion protection from the environment. Dupont's materials may be used as is or uncovered and rolled down onto a glass substrate. They need very little protection after being fully polymerized with UV light but a stiff flat backing helps with image distortion. Water can affect them temporarily but the structure is essentially humidity proof. == APPLICATION NOTES == DCG is easily the most versatile material, just about any kind of HOE or hologram can be made in it. Unfortunately it has poor environmental stability and must be well protected or it may not be intact when you need it. As long as glass or thick plastic is acceptable in the finished product DCG is the number one choice. With some difficulty it can be made panchromatic for full color work and under warm moist conditions it is a little more sensitive than the other two in the blue-green region. The SHG versions are much more sensitive and represent the only fast "non silver" medium useful for pulse holography applications. PVK is not so pleasant to work with as DCG but it goes onto plastic substrates easily, has a high delta n and needs only minimal protection. It should be very good for such things as eyewear, solar collection and other outdoor applications or anyplace where superb environmental stability is required. Dupont's materials come with an ever wider range of properties. They are durable and panchromatic but lack a little in dynamic range. The maximum available index modulation is lower than the other two materials and display holograms are typically less bright. Initially we tried to determine the index modulation of simple reflectors made in each material by fitting them to the simple one dimensional Kogelnick expression for diffraction efficiency (D.E.) of reflection volume holograms. {| border="1" |- ! colspan="2" | Kogelnick Expression |- | <math> DE = \tanh^2 \, {{\pi\Delta n T} \over {\lambda\sin\Theta}} </math> | Where *T = thickness of material in microns *λ = .5 microns (typical) *sin θ = 1 (for conformal mirror) |} This relationship seldom describes real reflection structures because it does not describe the effects of a gradient on the index modulation (delta n) or a chirp in the grating spacing (d). A gradient in delta n such as is caused by the absorption of light by the sensitizing dye results in a smooth broadening of the angular and spectral bandwidths and a smoothing of sideband peaks (when DE is held constant.) A chirp in the Bragg plane spacing also broadens the bandwidth though not so smoothly and the combination produces a highly asymmetric spectral bandwidth. The data and a description of the computer model is given in a previous publication. All three materials exhibit a useful range of index modulation and color control and each has found multiple commercial uses. The differences lie mainly in sensitometric characteristics, environmental stability and in the degree of difficulty to obtain or use. The balance of this paper will detail the use of DCG. We will try to give instructions that can be followed by anyone that is already familiar with more conventional holographic fabrication techniques and materials. Some details are left out for the sake of brevity but can be found elsewhere in the references or other literature. == SPIN COATING APPARATUS == A variable speed turntable capable of 50 to 100 RPM will coat films of gelatin or PVK from 4 to 50 microns on 8 x 10 inch glass or plastic substrates. Plates as small as 3 inch diameter or as large as 16 x 16 inches have also been successfully coated with this range and technique. The turntable should be equipped with a surface or arms that will mate to a removable tray that is one or two inches larger than the substrates being coated. We have used ordinary variable speed phonograph players with pie tins turned upside down and glued to the turntables and we have used Dayton variable speed gear motors with heavy duty arms attached. Both devices worked very well. Trays have been made up of stainless steel, plexiglass, polyethylene dishpans or modified from aluminum cake and pizza pans. The best trays have straight sides measuring 2 1/2 to 4 inches high and are fitted with 3 rubber posts inside and outside. The posts inside hold the substrate an inch or so off the bottom of the tray and the outside posts serve to level the tray during pouring of solutions and to center the tray during spinning. The spinning tray and substrate may generate useful turbulence that aids in drying and distributing the solution. Excess solution is caught in the tray and emptied between substrates then is easily soaked clean in hot water after a days activities. An important component that augments drying and uniformity is the blower-heater. It hangs off center and above the whirling tray. Turbulence and heat combine to make uniform coatings in about five minutes. We recommend the use of a variable temperature 600 watt blower such as might be found in the ceilings of some bathrooms. A little experimenting with angle and position will quickly determine the best place to hang this unit in your clean hood or bench area. Coat and examine uniformity by looking for local fringe patterns under a fluorescent lamp or better yet a fluorescent long wave black light. == BAR COATING APPARATUS == Lab coating bars are available from R.D. Specialty Co. in Webster N.Y. Ph (716)265-0220. A selection of bar types may be purchased for about $ 50.00. We have used bars of 3/8" diameter wound with # 24 wire as a standard but we have other windings and diameters on hand for special applications and recommend you do the same. These bars are also useful for applying strippable coatings for anti halo backings, and have been used for coating photopolymers and protective epoxy layers etc. Jigging for bar coating can be as simple as a clipboard with lint free paper placed under the substrate. A better jig is one that holds the plate above a trough that can catch run-off. The whole thing can be plexiglass which is particularly easy to get gelatin off of and it also preferentially over glass attracts dust particles. Bar or spin coating is done in a class 100 environment and is accomplished by pouring out a line of solution and pulling it down with a uniform pressure and velocity. A little practice will determine correct amount of solution, speed and pressure. The bar is not rotated as it is pulled and a new location or freshly cleaned and dried bar is used on each new substrate. Variations in thickness may be accomplished by changing wire size or viscosity or both. Precautions must be taken to keep the bars clean and undamaged. We place used bars in warm water and rinse and dry them before each use. A rack that holds them suspended above any surfaces is useful for storage, cleaning and serial use. It can be made from plastics or metals. Coated plates need to be placed in a level position where they can air dry in a few minutes. The coating jig should be nominally level. Cronar, (polyester) substrates are easily coated with these bars. Cronar is a Dupont product. One source is Farrest Chemical &amp; Supply, 680 Toland St., San Francisco, CA (415)8241400. It is available in sheets (C-42) or rolls (C-41) in a variety of sizes. Exposure of Cronar is done with a thick glass vacuum chuck or by humidifying the gelatin and rolling it against a clean glass plate. It is optically active and you may need to identify its neutral optical axis before exposure. Processing is best done by stretching it in a frame for dipping and agitation or by clipping it flush to a glass substrate fitted with a handle on one side. == FILM PREPARATION == Many factors need to be considered when mixing DCG for holographic film. === Jelly strength === The jelly strength, measured with the Bloom Gelometer, is an important consideration. The current gelatin being used by us for film production is either MCB brand (Mattheson, Coleman, and Bell Manufacturing Chemists, Norwood, OH 45212 # GX-45' OH 45212) # GX-45. Grayslake Type B USP XXIII Box 248 Grayslake,IL . 60030 Phone (312) 223-8141 Contact Bob Buscher. Both gelatins have bloom strengths from 215-235. Comparable with the jelly strength is the rated solubility of the gelatin, and the mode of manufacturing. (Acid or Alkaline processed.) These can each make a considerable difference in the quality for each lot. It is best to test every specific lot before final acceptance of a gelatin. Perhaps the best rating for gelatin to be used for DCG is the jelly strength-to-viscosity ratio. A ratio of at least 4 or 5 to 1 is considered good. Our current batch has a bloom of 232 grams, a viscosity of 42 mps and a ph of 5.1. === Heating === One important caution when preparing the DCG film mixture is the destabilization of the gelatin at high temperature. When heated for an excessive period of time, the film breaks up, causing what we term as film "pits" in the final emulsion. These "pits" have the appearance of small circles of various sizes and scatter themselves throughout the plate. When the film is processed, the final image has small voids where the "pits" were. So far, the length of the heating time and the peak temperature that cause this have not been determined. In the past, temperature and heating time causing this have fluctuated. But the safe method is to heat the film mixture at the shortest possible heating time to dissolve the gelatin content completely. 130 F to 150 F (60 C.) is usually a high enough temperature to dissolve without cooking. Gelatin "melts" around 40 to 45 C. The causes of film "pitting" are still unknown to us as well as what the "pits" really are. But their characteristics (and that of gelatin) can give us some ideas. It is important to take all known preventative measures for keeping them off the emulsion. Triple filtering helps and avoiding hot spots while mixing helps. We use a standard mag stir hot plate and glass flasks which are heated slowly while stirring or heated in a water bath, a microwave oven has also worked well using plastic bottles . Film "pitting", or destabilization, in the past, has seemed to be affected by the solubility of the gelatin. The higher the solubility, the less likely film "pits" occurred. The solubility, of course, is slightly affected by jelly strength and impurities. Literature within the gelatin film industry indicates temperature separation may occur, partly due to the polysaccharide content of the gelatin. There is one speculation of film pits which involves the crystallinity function in drying films. (And this is a function of film temperature.) The other theory for film "pits" is the presence of insoluble impurities (such as arsenic, grease, etc.) on the surface of the film. These substances probably conglomerate during mixing and heating to make larger hydrophobic areas on the glass. Surfactants would alleviate this but they aggravate adhesion problems as well. === Water === Use deionized water for the DCG film mixture. It eliminates certain salts which have produced inconsistencies in film behavior. Distilled water is also acceptable. Any water should be funnel filtered through a 5 micron or smaller filter and be free of oil, grease, and bacteria that thrive on gelatin. === Storage === Film mixtures may be stored in a refrigerator for a week or two and reheated in water or a microwave oven as needed. When stored longer the become less and less likely to flow when warmed. === Film codes === The film mixtures vary in dichromate and gelatin percentages. The variations depend on the specific use that a DCG film plate has. The film code currently used contains three numbers. The first being the gram-weight of the ammonium dichromate, the second being the gram-weight of the gelatin, and the third being the gram-weight (mls) of the water to be used in the film mixture. (Usually mixed in a 500 ml poly bottle.) The code for film used in broadband image holograms is 8-30-350. Thus, 8 grams dichromate, 30 grams gelatine, and 350 grams (mls) of water are mixed together. The mixture code for "red" holograms is 3-30-200. Most holographic optics are made in 10-30-250 to 8-30-150. Very thick coatings of 30 to 50 microns can be made using a 3-30-125 mixture but special fixturing may have to be made to get the gelatin to flow uniformly and the dried film may come off the substrate unless it is baked on at high humidity. We find adhesion is enhanced by cleaning the substrate in clorox and then baking the coated plate at 130 degree F in the presense of water at saturation. In using the film code for a variety of mixtures, the 30-gram gelatin weight number always remains constant. Thus, when a thicker emulsion is desired, the water number decreases. And when more absorption is desired, the dichromate number increases, an increase in thickness narrows the bandwidth and an increase in dichromate shifts the color toward the blue. As a general rule, thicker emulsions require longer process times but are easier to make uniform. The dichromate concentration determines light absorption and the center reconstruction wavelength of the hologram. For higher dichromate concentrations, the increased absorption produces larger gradients of index modulation. Lower the dichromate concentrations produce more uniform index modulations. Larger gradients yield slightly larger bandwidths and the removal of higher percentages of dichromate during processing results in thinner and thus bluer holograms. When a specific bandwidth is desired, along with a specific reconstruction wavelength; it is best to experiment with various film mixtures. Usually starting with a standard mixture and then adjusting the thickness, and dichromate content to achieve the desired results. The color controllability and uniformity of DCG film improves with thicker film emulsions. Consequently, they are more forgiving in their exposing and developing parameters. Extremely thick (25 micron or more) emulsions ( X-30-150, a 5 to 1 water-to-gel ratio) are difficult to use. They are prone to excess bubbles, pre-mature jelling, film pits, low viscous flow, increased impurities and during processing sometimes pull up off the substrate if not annealed in a wet oven. Processing of these thick films is often done with room temperature baths, or slightly elavated temperatures, over several minutes in each bath. === Sensitizer === We use ammonium dichromate crystals or for redder reds Potassium dichromate but the most sensitive of the dichromates is Pyridine dichromate. We don't use it because of it's shorter life and difficult preparation. The addition of ammonium nitrate can make the dichromate several times more sensitive, but decreases the useful life and blue shifts the image. Approximate ammonium nitrate concentrations are usually in a ratio of 1 to 5 by weight to ammonium dichromate up to a maximum of 1 to 1. When the additional substance is washed out of the gelatin a net shrinkage occurs which amounts to a blue shift in reflection holograms and lays down Bragg planes in transmission holograms. === Filtering === At a minimum, filter the heated mixture through two coffee filters (Mr. Coffee) for a standard 8-30-350 film. For 6-30-200 and thicker emulsions, use one coffee filter. Run the filtered mix into the pouring container. When necessary, a finer grade lab filter may be used, we have forced warm gelatin through a 1 micron filter using a gear pump and also using a peristaltic pump. The use of a peristaltic pump makes metering and filtering possible at the same time. A simple syringe with a 2 micron filter is very effective and may double as a way to meter out a fixed amount onto a plate. === Applicator === The pouring container (with the film) is kept on an electric warming plate. The temperature of the plate should be carefully controlled to provide only enough warmth to prevent jelling (50-60 degrees C). We like to use a lab hot plate and water bath, the pouring container is a tea pot like bottle modified from a lab wash bottle. Any poly bottle that empties from the bottom will do. Some custom shaping of the "spout" may be necessary to prevent the formation of bubbles. == COATING TECHNIQUES == The coating station consists of a class 100 cleanhood or laminar flow bench, a dryer-heater unit and the turntable. The clean hood should be large enough to fit the turntable and two plate racks inside. (About 2 1/2' x 3 1/2' or larger.) A yellow safelight may also be mounted inside. Air flow should be 200 cfm or higher for this size hood. === Cleaning glass === There is a bit of an art to coating and it takes a little practice to become good at it. The first step is to prepare the plates by soaking over night in a soapy solution that contains some chlorine. The plates also need scrubbing and a rinse in deionized water. The final rinse should be done in or in front of the clean hood used for drying the plates. The chlorine soak has been found to aid in adhesion of the gel to the glass. The glass may be soda lime plate or float glass or any most any other kind but it has to be thick enough to withstand the shrinking forces generated during exposure. This means that it should be double strength or thicker(3 to 6 mm) for 8 x 10 shots, single strength (2 to 3 mm) for 4 x 5 and 5 x 7, and may be picture glass or as thin as 1 mm for 2 x 2 exposures. === Coating glass === The gelatin is poured over the dried plate in such a way that no gel spills off the edge and no bubbles are formed. This is accomplished by pouring a large puddle and gently rocking the tray till all edges are wet. The turntable is then turned on with the blower/heater for about 5 minutes. If the plate was uniformly wet and had no contaminants then the coating is likely to be uniform using these techniques. The range of RPM we found useful runs from 65 to 100, speeds outside this range failed to be uniform. Start with a rotation speed of about 80 RPM and position the heater-blower about 6 inches above and to one side of center of the coating tray. For 8 by 10 plates this offset is about 3 inches. The fine tuning of the position of the blower will greatly improve the uniformity of your coatings. === Ageing and thickness === The film is ready for exposure after it has been aged an hour or so for a 350 mixture or a day later for a 150 mixture. The addition of 1 or 2 ml of TMG will extend the useful room temp life of 350 film to a day or two and will make 150 film last for several weeks in a 21 degree C, 50% RH environment. The thicknesses of the commonly used mixtures after spinning at 80 RPM and after processing are as follows: 350 yields 5-6 microns, 250 yields 8-9 microns, 200 yields 10-12 microns, 150 yields 20-24 microns and 125 yields 25 to 50 microns depending on speed. === Bandwidths and color === The relative bandwidths run from 50 to 150 nm for 350 film, depending on processing used. 250 and 200 film make 10 to 50 nm bandwidths depending on processing and 150 film can get down to 8 nm but also runs as high as 30 nm. Very thick film can have bandwidths of less than 8 nm. The color of a film made from a 3-30-200 mixture is around 630 nm when shot at 514 nm. The color of 6- 30 film is around 590 for a 514 shot and a 10-30 mixture will easily be tuned to play back at the same wavelength it was shot at. Methods of planning and controlling color in display holograms are discussed below, similar but more precise methods are used for HOEs. == COLOR DICHROMATE OBJECT PREPARATION == The two color method produces rich red-orange and bright clean blue-green colors that mix to a creamy white. Color coding of the object is optional but helpful in most cases and production is done from two masters in two different films. The three color system requires color coding for red at the mastering stage but no coding for blue or green, which are mastered first. Both systems are part natural, part pseudo color and require only two laser lines and two film formulations. Blue is obtained naturally by using the 458 argon line and green or red are derived from the 514 line. In production the two color system is identical to current master/copy methods in that batches are shot at 458 or at 514 and later registered and laminated together. The three color system requires blue and green exposures in the same emulsion and red in a second batch. The laser must then be operated multiline or be switched constantly or a second laser introduced. The preferred method is multiline operation with independent shuttering except that max power in each line is reduced because several lines compete for available energy. The two color, two plate system makes very satisfying flesh tones and color balance is fairly easy to maintain because it can be done by mixing and matching batches and or individual holograms at the laminating stage. The two color single plate method has the obvious advantage of no registration problems but it has a limited color range because there are only 56 nm between 458 and 514nm. === Object preparation === Blue-green areas should be overcoated lightly with a bright blue pigment such as Liquitex Brilliant Blue #20002-381 or Pelikan Deep Blue #39. This will effectively inhibit refection at 514. The red-orange areas must be touched up with yellow pigment such as Liquitex #1002-411 or Pelikan Yellow #10 both of which absorb 458 but reflect 514. At this stage H1 masters or correctly colored copies can be made, the Blue-Green master may be made to reconstruct at 488 so that production copies can be done using only 488 and 514. The 514 exposure is done with the film side facing the reference beam and the 458 exposure is done the other way around with a spacer between the object and film having the same optical thickness as the 514 substrate. === Film preparations === A good blue or green production film can be made by mixing the 8-30-250 formulae with or without a ml of TMG. A good red or yellow film is made by reducing the amount of dichromate to 2 or 3 grams. The plates are ready to use after standing at room temp for an hour and they may be stored in a refrigerator for months on end. Better results may be obtained from some softer gelatins by ageing films for a few days. === Exposure procedures === Blue holograms may be made by exposing in a Denisyuk fashion @ 458, 441, 476 nm or some other line bluer than 488. The energy required is about 20 mj/cm*cm and it helps to do it with the reference at 50 degrees from the normal and with the E vector perpendicular to the plate to reduce noise from mirroring. Green holograms may be similarly produced by using the 514 line, again near Brewster's angle. This time it may pay to try 55 degrees because absorption is much lower @ 514 so "Newton's wood" type noise is more likely to show up.The energy required is about 90 mj/cm*cm. Red holograms result from using the red film formula and exposing @ 514 close to Brewster's angle. The fringe structure is expanded to red or yellow reconstruction because less material is washed out during development. If the master has been made in SHG using a HeNe then this copy will be a correct color reproduction. === Processing procedures === The film of gelatin is about 8 or 9 microns thick and requires much longer processing times than 4 or 5 micron broadband films. Development takes 3 to 5 minutes in kodak fixer, followed by a 1 minute rinse in tap water. Dehydration is done in warm isopropyl alcohol (48 to 55 degrees C) using at least 2 baths after the tuning bath and agitating mildly in each for about 30 seconds. Drying is most easily done by removing the plate very slowly from the last and driest bath. If it does not look uniform try soaking in warm water for 10 minutes and then dehydrate with more agitation. Fine tuning of the color may be done by soaking in the tuning bath. This is the way that we get the center reconstruction frequency to match the copy wavelength. Start with a master that is a little too red and gradually tune it to the correct color by repeated passes through the tuning bath and the last hot dry bath. 350, 250, and even 200 mixtures all respond to this method. A hydrometer is necessary to monitor the specific gravity of the tuning bath and maintain it at or near .86. Processing 350 film for masters is done this way but the same film can be processed for broadband reconstruction by using a shorter development time and skipping the tuning bath. Experimenting is the only way to get the desired results. Some guides to broadband techniques can be found in the proceedings of the first Lake Forest symposium in 1982. An alternative to multiple bath processing has been proposed by workers at IBM. They suggest that for thin films, on the order of our 350 or 400 mixtures, spinning the plate while spraying a series of fluids works best. Thin films are not easy to process in baths because of the fast diffusion of solvents in and out of the rather porous gelatin. In the IBM method, all of the regular baths are sprayed progressively for only a few seconds each onto the spinning plate. They felt that the spray system would be a superior way to automate processing techniques, we experimented with spraying many years ago but did not have the success that IBM has had. === Hazards === Dichromate powder is dangerous if inhaled and the liquid mixture may irritate some people if left on the skin. Dust masks and rubber gloves are therefore recommended whenever film is being made. Isopropyl alcohol has low toxicity but is quite flammable and must always be heated in a safe manner such as in a water bath. Alcohol fires may be extinguished with water, dry chemical, Halon or CO₂. Glass must be handled carefully and whenever possible the edges should be ground before handling. == REFERENCES == These references are all by the same author and may be useful to the holographer that tries to apply the methods detailed in this paper. A design guide and brochure for HOE's is available on request. A video tape demonstrating this technology is also conditionally available from the author. *"Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)." S.P.I.E. Proceedings, Volume 212, pp. 22, 1979 *"Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College Holography Workshop and First International Symposium on Display Holography, July 1982. Lake Forest, IL. *"Practical Polymers for Holography", Second International Symposium on Display Holography, Lake Forest College, IL. *"Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug. 1987. *"Alternative Volume Recording Media, A Qualitative Comparison" Third International Symposium on Display Holography, Lake Forest College, IL 1988 *"Survey of properties of volume holographic materials", SPIE vol. 1051, Practicle Holography III, 1989 p. 68 - LA, CA. *"Novel Enhancement of Photopolymers", SPIE vol 1212, Practical Holography IV, 1990 LA, CA. '''''Last modified on 4/8/99''''' [[Category:Rallison]] 79c1cba9d704397ba51610054805ed64fe11e538 1974 1973 2013-05-17T03:17:57Z Jsfisher 1 /* Hazards */ wikitext text/x-wiki == ABSTRACT == We review the properties and relative usefulness of 3 non silver Volume holographic recording materials that are available today. Dichromated Gelatin (DCG) will receive the most attention followed by Dupont Omnidex products and a light treatment of Polyvinyl Carbazole (PVK). Enhancement and control of color, bandwidth and diffraction efficiency of volume reflection holograms recorded in DCG and photopolymers is discussed. Methods of increasing the bandwidth while shifting the center frequency toward the red is given for photopolymers. Red pseudo color will be covered thoroughly so that the practitioner will have all the elementary tools to make full color and broadband DCG holograms from scratch. The entire DCG technology is disclosed as it relates to production of high quality display holograms that span the spectrum and may be narrowband and very deep or shallow and broadband. == MATERIAL == The list of volume holographic recording materials includes the silver halide films, photopolymers, photocrosslinkers, photochromics, ferroelectric crystals and a few less well known oddities. While useful devices may be made in all these materials only a few will provide a holographer with a sufficiently high index modulation, resolution, signal to noise ratio, spectral response, and archival properties. The silver halide films have grain size limited resolution, scatter short wavelengths excessively, have only a moderate index modulation and tend to print out in UV light. They are popular for many applications because they can be made panchromatic, are much more sensitive than any other materials and are commercially available. We ocassionally use silver halide films to make master holograms and we reduce the blue scatter by converting them to a gelatin hologram (SHG). Used in this manner they are nearly equivalent to dichromated gelatin (DCG). They enable the production of DCG masters shot with red light at silver speeds that can be copied with green light in DCG and reconstructed finally at the original red color. SHG processes are covered in previous publications. The three materials detailed in this paper were chosen because they each have more or less all the properties needed for the construction of high quality or high efficiency broadband or narrowband color controlled holograms. They are not without faults however and the purpose of this work is to provide information to a holographer to assist him to make a better material choice for a particular task or to set up for production in DCG. Some information is given relating to the peculiar drop in average index in DCG, PVK and DMP128 due to the nature of the index modulation in these materials. Very thick coatings, up to about 50 microns are also dealt with in a special section. Comments made about preparation, processing, fine tuning, protection and applications are based on many years of working with DCG and many months of working with the other two materials, Dupont's Omnidex materials and Polyvinyl Carbazole (PVK). DMP 128 is another well documented material. It is a proprietary Polaroid formulation of lithium acrylate in combination with a branched polyethylenimine. Although it is not generally available commercially Polaroid has allowed laboratory evaluations and it is now quite common to get holograms mass produced in the material at Polaroid. Several other photopolymer systems are possibilities for holographic work but these 3 represent the readily available and practical recording materials of the day. == REFLECTION HOLOGRAM FABRICATION STEPS == === Mixing and coating === DCG is a mixture of Ammonium dichromate, gelatin and water. It is stirred together, heated, filtered and spun on or drawn down with a bar. Drying with or without heat from gel or liquid states makes little difference. Bright yellow lights are permissable. A 10 micron film can be made by mixing one gram dichromate with 3 grams of gelatin and 20 grams of water and spinning a flooded 8x10 glass plate at about 80 RPM. The solution and the coated plate is useful for about 3 days, much longer with refrigeration. PVK is dissolved in chlorobenzene along with Carbon tetraiodide, it is difficult to get into solution even with heat and agitation. It is also very unstable and may gel in as little as 15 minutes after mixing. The solution may be further thinned for convenient spinning but is easily applied with a bar. A number 28 bar will yield a 5 - 7 micron coating when 2 grams of PVK are dissolved in 25 grams of chlorobenzene. The patent disclosure mentions nothing about mixing the sensitizer with the PVK while still dry but if this is not done the solution will likely not be photosensitive. The solution will usually remain stable enough for coating for about 1 hour after mixing. The coated substrate is good for at least 8 hours. Dupont's materials can be purchased already to use on plastic substrates or may be obtained in liquid form for coating by any of the techniques covered here. === Storage after coating === DCG stores well at low humidity in a refrigerator or freezer but containers must prevent contamination, condensation, freezer burn and frost which can all destroy surface quality. Film of 10 to 20 microns or more store best and are good for at least a year. At room temperature and 50% RH, thin films are good for a few hours, thick films typically last a week or more. The addition of a small quantity of TMG to the mixture will greatly increase storage time at room temperature by increasing the PH. PVK does not store well as a rule, sometimes it has lasted a week in the refrigerator. Typically it moves suddenly to insensitivity within 24 hours and it does not seem to age gradually. The instabilities in coating and storing could be alleviated by adding more antioxidants to retard the spontaneous formation of free radicals but at the cost of reduced photo sensitivity. Dupont's materials seem to store well under refrigeration for a year or more depending on type, their newest film is also very sensitive, requiring only a few mj/cm*cm to expose in red or green. === Exposure characteristics === DCG is most sensitive in a hot moist environment. At 50% RH and 68 degrees F it may require 60 mj/cm*cm of 488 nm light, while at 75% RH and 80° F 4mJ/cm² will do the same job. At 441 nm less than 1 mJ is enough and at 514 or 532, 50 to 100 may be necessary. The percentage of dichromate affects speed more or less linearly, a 25% mixture is typical but mixtures of from 10 to 30 percent are necessary to control color. Gross overexposure will cause a decrease in efficiency all the way to zero. Overexposure causes an initial increase then a decrease in bandwidth and a blue shift plus a compression of contrast or dynamic range. PVK is totally insensitive to moisture, water can be used as an index matching fluid with no effect on the hologram. It requires about 20 mj/cm*cm at 488 nm to make a good single beam reflection hologram and because it is a cross linker it can be overexposed. Over exposure also results in a blue shift, a wider, then narrower bandwidth and loss of contrast. The Dupont material is a real time material and as a result can interfere with itself during an exposure. As the hologram is forming it is also reconstructing and making small dimensional changes. The results can be that at some time during an exposure the reconstruction could be out of phase with the construction momentarily. The energy required varies from about 8 mJ/cm² to a 100 or so mJ. It has good resistance to water and readable holograms have been made by us in 100ms. === Processing procedures === DCG is hardened briefly in Kodak Fixer with hardener then rinsed and plunged into several hot or cool alcohol baths. Cool baths produce better uniformity and lower noise, hot baths can yield tremendous index modulations with large chirps in Bragg spacing but often with increased noise. Depending on the mixtures, temperatures and times spent in each bath, a wide range of effects can be had. Processing and reprocessing affects bandwidth and center frequency over 100 nm or more and index modulation can be varied from near nothing to .25. If the first pass in the baths produces a shift to red, a second pass can shift it to blue and a 100 nm bandwidth can be reprocessed to yield a 30 nm bandwidth. Typically "master" holograms are processed to construct near the recording wavelength but processing and dichromate content allow the control of color to range from 650 to 450 nm for a straight on exposure at 488 nm. This much versatility in color control is certainly useful and will be covered in more detail. Conformal mirrors on flat substrates can be color shifted easily with angle but more complex shapes must be tuned with processing and film formula juggling. As an example of a reprocessing procedure, a red shifted broadband mirror may be narrowed and blue shifted by agitation for 30 seconds in a room temp 50:50 mixture of water and alcohol then plunged into 99% hot alcohol with agitation for 30 seconds and pulled slowly from the hot bath. The direction of the shift can be controlled by the ratio of alcohol and water in the first bath and the amount of shift can be controlled by the time in the same bath. A near ideal tuning bath has a specific gravity of .86 when it is warmed to about 55 degrees C. This process can be repeated many times if necessary, especially if the last hot bath is not hot enough to cause excessive scattering center buildup. Multiple buffer baths between the first color control bath and the last dehydration bath help to keep the last bath clean. PVK is swollen in Xylene or Toluene for a few seconds then dried in warm Hexanes or Hexanes mixed with alcohols. Like DCG the latent image must be enhanced by swelling in the first solvent and then replacing that solvent with a miscible but nonswelling solvent. Again, color and modulation control is by temperature and time. Color control is similar to DCG methods and either broadband red shifts or narrowband blue shifts are possible by altering time and temperature. Reprocessing is possible but scattering centers build up rather quickly in this material. The first solvent probably dissolves away material as it causes swelling. Signal to noise is usually good in narrow band processing but not so good for broadband reconstructions. A recent proprietary improvement in processing involves the use of a clever monobath made up of two miscible solvents. One of the solvents will swell the PVK and is more volatile than the other solvent which will not soften or swell the PVK. The most volatile solvent evaporates first and leaves the hologram structure in rigid uniform shape while the second solvent is driven out with warm dry air. Dupont films are developed with UV light and heat. They may then be brightened and color shifted by the addition of monomers and or solvents. It is common practice to laminate a cover glass over gelatin holograms to protect them from moisture, abrasion and chemicals. Many common epoxies have been identified as safe for this purpose as well as a broad class of adhesives described as UV polymerizable substances,( monomers, epoxies, resins, adhesives, etc). I accidentally caused an enhancement of several photopolymer holograms while attempting to laminate them. In one case the bandwidth widened from 40 nm to 150 nm and the optical density remained almost as high as the original structure. The photopolymers behave a little like sponges that can be dampened and swollen or alternatively soaked and saturated while the shock dried DCG and PVK structures are more like a stack of Ruffles potato chips that get damp, go limp and then collapse. Enhancement of Dupont photopolymer is the easiest and most reliable. The holograms produced from blue exposures originally playback blue but the enhanced holograms playback at a longer wavelength and are noticeably brighter. Solvents alone brighten and shift the reconstructions to the red but they are temporary treatments and not generally as effective as UV curable monomer type adhesives. A Dupont product is now available to make predictable shifts in playback color. They provide a monomer on a cover sheet that will diffuse into the exposed film where it causes swelling and can then be fixed by polymerization under a UV source. Some Dupont film reflection holograms will respond to the following recipe with a red shift and increase in total diffracted energy. Apply Lightweld 401 evenly and cover then wait for a color change and cure with strong UV source. If this substance is left uncured it may destroy the original structure. It is also anaerobic and therefore requires a cover to cure. === Protection === DCG is notoriously bad at remaining stable in normal environments. Moisture will cause the Bragg structure to collapse and the gelatin grabs moisture easily from the air right through most plastics and glue. This material usually requires lamination between glass with enough gelatin removed around the edges to form an "O" ring seal. Thick plastics, such as 30 mil mylar, will also work and certain fluorinated plastics such as "Aclar" in thin 5 mill layers are satisfactory provided that the edges have been cleared of gelatin before laminating. PVK needs protection from abrasion but it stands alone as the only holographic material we ever worked with that is completely waterproof. It requires only a 4 mil mylar laminate for adequate abrasion protection from the environment. Dupont's materials may be used as is or uncovered and rolled down onto a glass substrate. They need very little protection after being fully polymerized with UV light but a stiff flat backing helps with image distortion. Water can affect them temporarily but the structure is essentially humidity proof. == APPLICATION NOTES == DCG is easily the most versatile material, just about any kind of HOE or hologram can be made in it. Unfortunately it has poor environmental stability and must be well protected or it may not be intact when you need it. As long as glass or thick plastic is acceptable in the finished product DCG is the number one choice. With some difficulty it can be made panchromatic for full color work and under warm moist conditions it is a little more sensitive than the other two in the blue-green region. The SHG versions are much more sensitive and represent the only fast "non silver" medium useful for pulse holography applications. PVK is not so pleasant to work with as DCG but it goes onto plastic substrates easily, has a high delta n and needs only minimal protection. It should be very good for such things as eyewear, solar collection and other outdoor applications or anyplace where superb environmental stability is required. Dupont's materials come with an ever wider range of properties. They are durable and panchromatic but lack a little in dynamic range. The maximum available index modulation is lower than the other two materials and display holograms are typically less bright. Initially we tried to determine the index modulation of simple reflectors made in each material by fitting them to the simple one dimensional Kogelnick expression for diffraction efficiency (D.E.) of reflection volume holograms. {| border="1" |- ! colspan="2" | Kogelnick Expression |- | <math> DE = \tanh^2 \, {{\pi\Delta n T} \over {\lambda\sin\Theta}} </math> | Where *T = thickness of material in microns *λ = .5 microns (typical) *sin θ = 1 (for conformal mirror) |} This relationship seldom describes real reflection structures because it does not describe the effects of a gradient on the index modulation (delta n) or a chirp in the grating spacing (d). A gradient in delta n such as is caused by the absorption of light by the sensitizing dye results in a smooth broadening of the angular and spectral bandwidths and a smoothing of sideband peaks (when DE is held constant.) A chirp in the Bragg plane spacing also broadens the bandwidth though not so smoothly and the combination produces a highly asymmetric spectral bandwidth. The data and a description of the computer model is given in a previous publication. All three materials exhibit a useful range of index modulation and color control and each has found multiple commercial uses. The differences lie mainly in sensitometric characteristics, environmental stability and in the degree of difficulty to obtain or use. The balance of this paper will detail the use of DCG. We will try to give instructions that can be followed by anyone that is already familiar with more conventional holographic fabrication techniques and materials. Some details are left out for the sake of brevity but can be found elsewhere in the references or other literature. == SPIN COATING APPARATUS == A variable speed turntable capable of 50 to 100 RPM will coat films of gelatin or PVK from 4 to 50 microns on 8 x 10 inch glass or plastic substrates. Plates as small as 3 inch diameter or as large as 16 x 16 inches have also been successfully coated with this range and technique. The turntable should be equipped with a surface or arms that will mate to a removable tray that is one or two inches larger than the substrates being coated. We have used ordinary variable speed phonograph players with pie tins turned upside down and glued to the turntables and we have used Dayton variable speed gear motors with heavy duty arms attached. Both devices worked very well. Trays have been made up of stainless steel, plexiglass, polyethylene dishpans or modified from aluminum cake and pizza pans. The best trays have straight sides measuring 2 1/2 to 4 inches high and are fitted with 3 rubber posts inside and outside. The posts inside hold the substrate an inch or so off the bottom of the tray and the outside posts serve to level the tray during pouring of solutions and to center the tray during spinning. The spinning tray and substrate may generate useful turbulence that aids in drying and distributing the solution. Excess solution is caught in the tray and emptied between substrates then is easily soaked clean in hot water after a days activities. An important component that augments drying and uniformity is the blower-heater. It hangs off center and above the whirling tray. Turbulence and heat combine to make uniform coatings in about five minutes. We recommend the use of a variable temperature 600 watt blower such as might be found in the ceilings of some bathrooms. A little experimenting with angle and position will quickly determine the best place to hang this unit in your clean hood or bench area. Coat and examine uniformity by looking for local fringe patterns under a fluorescent lamp or better yet a fluorescent long wave black light. == BAR COATING APPARATUS == Lab coating bars are available from R.D. Specialty Co. in Webster N.Y. Ph (716)265-0220. A selection of bar types may be purchased for about $ 50.00. We have used bars of 3/8" diameter wound with # 24 wire as a standard but we have other windings and diameters on hand for special applications and recommend you do the same. These bars are also useful for applying strippable coatings for anti halo backings, and have been used for coating photopolymers and protective epoxy layers etc. Jigging for bar coating can be as simple as a clipboard with lint free paper placed under the substrate. A better jig is one that holds the plate above a trough that can catch run-off. The whole thing can be plexiglass which is particularly easy to get gelatin off of and it also preferentially over glass attracts dust particles. Bar or spin coating is done in a class 100 environment and is accomplished by pouring out a line of solution and pulling it down with a uniform pressure and velocity. A little practice will determine correct amount of solution, speed and pressure. The bar is not rotated as it is pulled and a new location or freshly cleaned and dried bar is used on each new substrate. Variations in thickness may be accomplished by changing wire size or viscosity or both. Precautions must be taken to keep the bars clean and undamaged. We place used bars in warm water and rinse and dry them before each use. A rack that holds them suspended above any surfaces is useful for storage, cleaning and serial use. It can be made from plastics or metals. Coated plates need to be placed in a level position where they can air dry in a few minutes. The coating jig should be nominally level. Cronar, (polyester) substrates are easily coated with these bars. Cronar is a Dupont product. One source is Farrest Chemical &amp; Supply, 680 Toland St., San Francisco, CA (415)8241400. It is available in sheets (C-42) or rolls (C-41) in a variety of sizes. Exposure of Cronar is done with a thick glass vacuum chuck or by humidifying the gelatin and rolling it against a clean glass plate. It is optically active and you may need to identify its neutral optical axis before exposure. Processing is best done by stretching it in a frame for dipping and agitation or by clipping it flush to a glass substrate fitted with a handle on one side. == FILM PREPARATION == Many factors need to be considered when mixing DCG for holographic film. === Jelly strength === The jelly strength, measured with the Bloom Gelometer, is an important consideration. The current gelatin being used by us for film production is either MCB brand (Mattheson, Coleman, and Bell Manufacturing Chemists, Norwood, OH 45212 # GX-45' OH 45212) # GX-45. Grayslake Type B USP XXIII Box 248 Grayslake,IL . 60030 Phone (312) 223-8141 Contact Bob Buscher. Both gelatins have bloom strengths from 215-235. Comparable with the jelly strength is the rated solubility of the gelatin, and the mode of manufacturing. (Acid or Alkaline processed.) These can each make a considerable difference in the quality for each lot. It is best to test every specific lot before final acceptance of a gelatin. Perhaps the best rating for gelatin to be used for DCG is the jelly strength-to-viscosity ratio. A ratio of at least 4 or 5 to 1 is considered good. Our current batch has a bloom of 232 grams, a viscosity of 42 mps and a ph of 5.1. === Heating === One important caution when preparing the DCG film mixture is the destabilization of the gelatin at high temperature. When heated for an excessive period of time, the film breaks up, causing what we term as film "pits" in the final emulsion. These "pits" have the appearance of small circles of various sizes and scatter themselves throughout the plate. When the film is processed, the final image has small voids where the "pits" were. So far, the length of the heating time and the peak temperature that cause this have not been determined. In the past, temperature and heating time causing this have fluctuated. But the safe method is to heat the film mixture at the shortest possible heating time to dissolve the gelatin content completely. 130 F to 150 F (60 C.) is usually a high enough temperature to dissolve without cooking. Gelatin "melts" around 40 to 45 C. The causes of film "pitting" are still unknown to us as well as what the "pits" really are. But their characteristics (and that of gelatin) can give us some ideas. It is important to take all known preventative measures for keeping them off the emulsion. Triple filtering helps and avoiding hot spots while mixing helps. We use a standard mag stir hot plate and glass flasks which are heated slowly while stirring or heated in a water bath, a microwave oven has also worked well using plastic bottles . Film "pitting", or destabilization, in the past, has seemed to be affected by the solubility of the gelatin. The higher the solubility, the less likely film "pits" occurred. The solubility, of course, is slightly affected by jelly strength and impurities. Literature within the gelatin film industry indicates temperature separation may occur, partly due to the polysaccharide content of the gelatin. There is one speculation of film pits which involves the crystallinity function in drying films. (And this is a function of film temperature.) The other theory for film "pits" is the presence of insoluble impurities (such as arsenic, grease, etc.) on the surface of the film. These substances probably conglomerate during mixing and heating to make larger hydrophobic areas on the glass. Surfactants would alleviate this but they aggravate adhesion problems as well. === Water === Use deionized water for the DCG film mixture. It eliminates certain salts which have produced inconsistencies in film behavior. Distilled water is also acceptable. Any water should be funnel filtered through a 5 micron or smaller filter and be free of oil, grease, and bacteria that thrive on gelatin. === Storage === Film mixtures may be stored in a refrigerator for a week or two and reheated in water or a microwave oven as needed. When stored longer the become less and less likely to flow when warmed. === Film codes === The film mixtures vary in dichromate and gelatin percentages. The variations depend on the specific use that a DCG film plate has. The film code currently used contains three numbers. The first being the gram-weight of the ammonium dichromate, the second being the gram-weight of the gelatin, and the third being the gram-weight (mls) of the water to be used in the film mixture. (Usually mixed in a 500 ml poly bottle.) The code for film used in broadband image holograms is 8-30-350. Thus, 8 grams dichromate, 30 grams gelatine, and 350 grams (mls) of water are mixed together. The mixture code for "red" holograms is 3-30-200. Most holographic optics are made in 10-30-250 to 8-30-150. Very thick coatings of 30 to 50 microns can be made using a 3-30-125 mixture but special fixturing may have to be made to get the gelatin to flow uniformly and the dried film may come off the substrate unless it is baked on at high humidity. We find adhesion is enhanced by cleaning the substrate in clorox and then baking the coated plate at 130 degree F in the presense of water at saturation. In using the film code for a variety of mixtures, the 30-gram gelatin weight number always remains constant. Thus, when a thicker emulsion is desired, the water number decreases. And when more absorption is desired, the dichromate number increases, an increase in thickness narrows the bandwidth and an increase in dichromate shifts the color toward the blue. As a general rule, thicker emulsions require longer process times but are easier to make uniform. The dichromate concentration determines light absorption and the center reconstruction wavelength of the hologram. For higher dichromate concentrations, the increased absorption produces larger gradients of index modulation. Lower the dichromate concentrations produce more uniform index modulations. Larger gradients yield slightly larger bandwidths and the removal of higher percentages of dichromate during processing results in thinner and thus bluer holograms. When a specific bandwidth is desired, along with a specific reconstruction wavelength; it is best to experiment with various film mixtures. Usually starting with a standard mixture and then adjusting the thickness, and dichromate content to achieve the desired results. The color controllability and uniformity of DCG film improves with thicker film emulsions. Consequently, they are more forgiving in their exposing and developing parameters. Extremely thick (25 micron or more) emulsions ( X-30-150, a 5 to 1 water-to-gel ratio) are difficult to use. They are prone to excess bubbles, pre-mature jelling, film pits, low viscous flow, increased impurities and during processing sometimes pull up off the substrate if not annealed in a wet oven. Processing of these thick films is often done with room temperature baths, or slightly elavated temperatures, over several minutes in each bath. === Sensitizer === We use ammonium dichromate crystals or for redder reds Potassium dichromate but the most sensitive of the dichromates is Pyridine dichromate. We don't use it because of it's shorter life and difficult preparation. The addition of ammonium nitrate can make the dichromate several times more sensitive, but decreases the useful life and blue shifts the image. Approximate ammonium nitrate concentrations are usually in a ratio of 1 to 5 by weight to ammonium dichromate up to a maximum of 1 to 1. When the additional substance is washed out of the gelatin a net shrinkage occurs which amounts to a blue shift in reflection holograms and lays down Bragg planes in transmission holograms. === Filtering === At a minimum, filter the heated mixture through two coffee filters (Mr. Coffee) for a standard 8-30-350 film. For 6-30-200 and thicker emulsions, use one coffee filter. Run the filtered mix into the pouring container. When necessary, a finer grade lab filter may be used, we have forced warm gelatin through a 1 micron filter using a gear pump and also using a peristaltic pump. The use of a peristaltic pump makes metering and filtering possible at the same time. A simple syringe with a 2 micron filter is very effective and may double as a way to meter out a fixed amount onto a plate. === Applicator === The pouring container (with the film) is kept on an electric warming plate. The temperature of the plate should be carefully controlled to provide only enough warmth to prevent jelling (50-60 degrees C). We like to use a lab hot plate and water bath, the pouring container is a tea pot like bottle modified from a lab wash bottle. Any poly bottle that empties from the bottom will do. Some custom shaping of the "spout" may be necessary to prevent the formation of bubbles. == COATING TECHNIQUES == The coating station consists of a class 100 cleanhood or laminar flow bench, a dryer-heater unit and the turntable. The clean hood should be large enough to fit the turntable and two plate racks inside. (About 2 1/2' x 3 1/2' or larger.) A yellow safelight may also be mounted inside. Air flow should be 200 cfm or higher for this size hood. === Cleaning glass === There is a bit of an art to coating and it takes a little practice to become good at it. The first step is to prepare the plates by soaking over night in a soapy solution that contains some chlorine. The plates also need scrubbing and a rinse in deionized water. The final rinse should be done in or in front of the clean hood used for drying the plates. The chlorine soak has been found to aid in adhesion of the gel to the glass. The glass may be soda lime plate or float glass or any most any other kind but it has to be thick enough to withstand the shrinking forces generated during exposure. This means that it should be double strength or thicker(3 to 6 mm) for 8 x 10 shots, single strength (2 to 3 mm) for 4 x 5 and 5 x 7, and may be picture glass or as thin as 1 mm for 2 x 2 exposures. === Coating glass === The gelatin is poured over the dried plate in such a way that no gel spills off the edge and no bubbles are formed. This is accomplished by pouring a large puddle and gently rocking the tray till all edges are wet. The turntable is then turned on with the blower/heater for about 5 minutes. If the plate was uniformly wet and had no contaminants then the coating is likely to be uniform using these techniques. The range of RPM we found useful runs from 65 to 100, speeds outside this range failed to be uniform. Start with a rotation speed of about 80 RPM and position the heater-blower about 6 inches above and to one side of center of the coating tray. For 8 by 10 plates this offset is about 3 inches. The fine tuning of the position of the blower will greatly improve the uniformity of your coatings. === Ageing and thickness === The film is ready for exposure after it has been aged an hour or so for a 350 mixture or a day later for a 150 mixture. The addition of 1 or 2 ml of TMG will extend the useful room temp life of 350 film to a day or two and will make 150 film last for several weeks in a 21 degree C, 50% RH environment. The thicknesses of the commonly used mixtures after spinning at 80 RPM and after processing are as follows: 350 yields 5-6 microns, 250 yields 8-9 microns, 200 yields 10-12 microns, 150 yields 20-24 microns and 125 yields 25 to 50 microns depending on speed. === Bandwidths and color === The relative bandwidths run from 50 to 150 nm for 350 film, depending on processing used. 250 and 200 film make 10 to 50 nm bandwidths depending on processing and 150 film can get down to 8 nm but also runs as high as 30 nm. Very thick film can have bandwidths of less than 8 nm. The color of a film made from a 3-30-200 mixture is around 630 nm when shot at 514 nm. The color of 6- 30 film is around 590 for a 514 shot and a 10-30 mixture will easily be tuned to play back at the same wavelength it was shot at. Methods of planning and controlling color in display holograms are discussed below, similar but more precise methods are used for HOEs. == COLOR DICHROMATE OBJECT PREPARATION == The two color method produces rich red-orange and bright clean blue-green colors that mix to a creamy white. Color coding of the object is optional but helpful in most cases and production is done from two masters in two different films. The three color system requires color coding for red at the mastering stage but no coding for blue or green, which are mastered first. Both systems are part natural, part pseudo color and require only two laser lines and two film formulations. Blue is obtained naturally by using the 458 argon line and green or red are derived from the 514 line. In production the two color system is identical to current master/copy methods in that batches are shot at 458 or at 514 and later registered and laminated together. The three color system requires blue and green exposures in the same emulsion and red in a second batch. The laser must then be operated multiline or be switched constantly or a second laser introduced. The preferred method is multiline operation with independent shuttering except that max power in each line is reduced because several lines compete for available energy. The two color, two plate system makes very satisfying flesh tones and color balance is fairly easy to maintain because it can be done by mixing and matching batches and or individual holograms at the laminating stage. The two color single plate method has the obvious advantage of no registration problems but it has a limited color range because there are only 56 nm between 458 and 514nm. === Object preparation === Blue-green areas should be overcoated lightly with a bright blue pigment such as Liquitex Brilliant Blue #20002-381 or Pelikan Deep Blue #39. This will effectively inhibit refection at 514. The red-orange areas must be touched up with yellow pigment such as Liquitex #1002-411 or Pelikan Yellow #10 both of which absorb 458 but reflect 514. At this stage H1 masters or correctly colored copies can be made, the Blue-Green master may be made to reconstruct at 488 so that production copies can be done using only 488 and 514. The 514 exposure is done with the film side facing the reference beam and the 458 exposure is done the other way around with a spacer between the object and film having the same optical thickness as the 514 substrate. === Film preparations === A good blue or green production film can be made by mixing the 8-30-250 formulae with or without a ml of TMG. A good red or yellow film is made by reducing the amount of dichromate to 2 or 3 grams. The plates are ready to use after standing at room temp for an hour and they may be stored in a refrigerator for months on end. Better results may be obtained from some softer gelatins by ageing films for a few days. === Exposure procedures === Blue holograms may be made by exposing in a Denisyuk fashion @ 458, 441, 476 nm or some other line bluer than 488. The energy required is about 20 mj/cm*cm and it helps to do it with the reference at 50 degrees from the normal and with the E vector perpendicular to the plate to reduce noise from mirroring. Green holograms may be similarly produced by using the 514 line, again near Brewster's angle. This time it may pay to try 55 degrees because absorption is much lower @ 514 so "Newton's wood" type noise is more likely to show up.The energy required is about 90 mj/cm*cm. Red holograms result from using the red film formula and exposing @ 514 close to Brewster's angle. The fringe structure is expanded to red or yellow reconstruction because less material is washed out during development. If the master has been made in SHG using a HeNe then this copy will be a correct color reproduction. === Processing procedures === The film of gelatin is about 8 or 9 microns thick and requires much longer processing times than 4 or 5 micron broadband films. Development takes 3 to 5 minutes in kodak fixer, followed by a 1 minute rinse in tap water. Dehydration is done in warm isopropyl alcohol (48 to 55 degrees C) using at least 2 baths after the tuning bath and agitating mildly in each for about 30 seconds. Drying is most easily done by removing the plate very slowly from the last and driest bath. If it does not look uniform try soaking in warm water for 10 minutes and then dehydrate with more agitation. Fine tuning of the color may be done by soaking in the tuning bath. This is the way that we get the center reconstruction frequency to match the copy wavelength. Start with a master that is a little too red and gradually tune it to the correct color by repeated passes through the tuning bath and the last hot dry bath. 350, 250, and even 200 mixtures all respond to this method. A hydrometer is necessary to monitor the specific gravity of the tuning bath and maintain it at or near .86. Processing 350 film for masters is done this way but the same film can be processed for broadband reconstruction by using a shorter development time and skipping the tuning bath. Experimenting is the only way to get the desired results. Some guides to broadband techniques can be found in the proceedings of the first Lake Forest symposium in 1982. An alternative to multiple bath processing has been proposed by workers at IBM. They suggest that for thin films, on the order of our 350 or 400 mixtures, spinning the plate while spraying a series of fluids works best. Thin films are not easy to process in baths because of the fast diffusion of solvents in and out of the rather porous gelatin. In the IBM method, all of the regular baths are sprayed progressively for only a few seconds each onto the spinning plate. They felt that the spray system would be a superior way to automate processing techniques, we experimented with spraying many years ago but did not have the success that IBM has had. == HAZARDS == Dichromate powder is dangerous if inhaled and the liquid mixture may irritate some people if left on the skin. Dust masks and rubber gloves are therefore recommended whenever film is being made. Isopropyl alcohol has low toxicity but is quite flammable and must always be heated in a safe manner such as in a water bath. Alcohol fires may be extinguished with water, dry chemical, Halon or CO₂. Glass must be handled carefully and whenever possible the edges should be ground before handling. == REFERENCES == These references are all by the same author and may be useful to the holographer that tries to apply the methods detailed in this paper. A design guide and brochure for HOE's is available on request. A video tape demonstrating this technology is also conditionally available from the author. *"Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)." S.P.I.E. Proceedings, Volume 212, pp. 22, 1979 *"Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College Holography Workshop and First International Symposium on Display Holography, July 1982. Lake Forest, IL. *"Practical Polymers for Holography", Second International Symposium on Display Holography, Lake Forest College, IL. *"Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug. 1987. *"Alternative Volume Recording Media, A Qualitative Comparison" Third International Symposium on Display Holography, Lake Forest College, IL 1988 *"Survey of properties of volume holographic materials", SPIE vol. 1051, Practicle Holography III, 1989 p. 68 - LA, CA. *"Novel Enhancement of Photopolymers", SPIE vol 1212, Practical Holography IV, 1990 LA, CA. '''''Last modified on 4/8/99''''' [[Category:Rallison]] 48b96fbe5a963aee8385a0f829af81315ffe3a4d 0 511 1975 1817 2013-05-18T01:11:16Z Jsfisher 1 wikitext text/x-wiki = Lippmann’s photography on dichromated gelatin plate = Sogonkon' A. B. {{Note | This article was transcribed from the text in the [[Media : Sogokon Lipp phot on DCG.pdf | file available here]].}} The research of properties of Lippmann’s images obtained on dichromated gelatin plate shows that image color depends on wavelength of radiation as well as on its intensity. It relates to heterogeneous swelling of gelatin and structural changes of its unirradiated parts at fast dehydration. Unusual behaviour of Lippmann’s images on dichromated gelatin plate may be used for producing selective mirrors for reflecting graphic information and date registration and image processing. == Introduction == There is [1] a method of obtaining color image based on registration of standing waves in the volume of thick transparent photographic emulsion. Period of registered interference structure is unambiguously related to the length of the wave of radiation influencing the plate. This assures right color rendering of photographed image if disposed to white radiation. This method wasn't widely adopted because of big technical problems. Development of holography leads to creation of a totally new technique of experiment and new registering mediums. There appeared some announcements that Lippmann’s images have been tried on modern emulsions like ЛОИ-2 [2,3] and on dichromated gelatin [4,5]. The aim of this work is to investigate the behaviour of Lippmann’s images made on dichromated gelatin as well as mechanism of image formation and possibilities of its application on practice. == Method and results of experiment == Lippmann’s method is basic for making dichromated gelatin plates [6]. Holographic plates ПЭ-2 and ЛОИ-2 were placed into acid fixing solution then washed in running water and dried at room temperature. The plates were sensitized right before exposure. For this the plate was placed for 5-15 minutes into 1-5% solution of dichromated ammonium and after its runoff dried by hot air current at temperature 100-150°C. The duration of drying is 3-5 minutes. [[Image:LippmannFig1.jpg|center|Image 1. Scheme of device for contact printing of Lippmann’s images. 1 – light source (laser or mercury lamp), 2 – lens, 3 – negative, 4 - dichromated gelatin plate.]] Scheme of device for contact printing of Lippmann’s images is displayed on image 1. Widened laser beam is directed onto registering medium. The radiation passed through reflected from plate glass spreads in reverse and forms a standing wave in the volume of registering medium the amplitude of which depends of negative passing. As the source of radiation lasers ЛПМ-11(442nm) and ЛГИ-21 (337nm) and mercury lamp ДРШ-250 were used. Besides direct projecting printing of enlarged images was realized with help of a usual photographic enlarger. Processing mode of exposured plates hardly differed from that of dichromated gelatin for obtaining hologram [7]. Images obtained using the foregoing method have a number of interesting qualities. If watching at an image in reflected light (almost natural light rays falling) different parts of the image get different colors according to density of initial negative. The image gets blue color under transparent parts and red color under opaque ones. Half-tints of negative are reproduced by hues from orange to green. From this follows that interference structure period depends on length of radiation wave as well as on its intensity. A Lippmann’s image if placed on a black sheet of paper and watched at broad angle will be black-and-white. Gelatin remains transparent under transparent parts of the image and gets milkwhite under opaque parts. In this case the image is not reproduced by light absorption but its dispersion that resembles the properties of display on vesicular materials [8]. To investigate the dependence of image color on the exposure within one plate a number of exposures was done by collimated laser beam. There were made also photos of sensitometric wedge image and then spectrums of transmission of the received images measured. On image 2 there are spectral characteristics of images obtained on ПЭ-2 plates sensitized by 1% ammonium solution at exposure by laser ЛПМ-11 (image 2,a) and ЛГИ-21 (image 2, г). It follows from the analysis of spectrums that spectrum reflection width (image 2, e), length of wave maximum reflection (image 2, в) and density of image (image 2, б, д), change according to exposure amount. It is significant that length of wave maximum reflection at considerable exposure does not correspond to the length of radiation wave of the record. It’s due to increasing period of interference structure at layer processing. [[Image:LippmannFig2.jpg|center|Image 2. Lippmann’s images characteristics: а and г - dependence of image transmission spectrums on exposure amount at recording by radiation of helium-cadmium (442 nm) and nitrogen (337 nm) lasers; б and д – dependence of image density on exposure for the same wave length; в – dependence of image color on exposure logarithm (curve 1 – 442, curve 2 – 337 nm); dependence of half-width of transmission spectrums on exposure (1 – 442, 2 – 337 nm).]] Length of wave maximum reflection linearly depends on logarithm of exposure (image 2, в) what gives possibility to write <div> <p style="float: left; width: 90%; text-align: center;"><math>\displaystyle \lambda - \lambda_0 = k (\log{H_{max}} - \log{H})</math></p> <p style="float: left; width: 10%; text-align: center;">(1)</p> <p style="width: 100% /> </div> where λo - length of wave maximum reflection at high energy of exposure (wave length of saturation), H – energy of exposure, k – coefficient of proportionality which may be interpreted as coefficient of colors contrast. Image color change evokes change of its density (image 2, б, д). These dependences are similar to characteristics curve of nigrescence of simple registering mediums. Nevertheless photographic width of linear region is much smaller. Dispersion of experimental points is especially considerable in regions of high exposure that can’t be explained by measurement errors. We can suppose that dependence of image transmission in region of saturation has oscillating character as demonstrated for example on image 2, д. == Mechanism of image creation == Preparing plates to sensitizing they should be placed into water for a period of time (about one hour). As a result gelatin gets swelled and long protein molecules swivel in the way to create linear chains. It relates more to molecules on the surface of the layer than those which are deep in as they are less exposed to strength of adjacent molecules. There appears a heterogeneous hardening increasing from the layer surface to substrate. Superficial gelatin molecules forming linear chains can no longer perform work as they took favorable energetic position. Molecules deep in the layer have some amount of potential energy. Their interaction with each other and molecules of gelatin hardener prevents their forming linear chains. This hardening can be defined as value inversely proportional to work performed by molecules when processed in water. The layer is not hardened if molecules realized their potential. The layer is hardened If they didn't realize their potential energy when processed in water. Distribution of potential energy in the thickness of hardened layer may be presented in diagram form as demonstrated on image 3,a. Let’s consider processes taking place at hardening of exposed layers. Here we consider that photochemical transformations Cr (VI) to Cr (III) is realized according to model described in work [9]. At low exposure energies the number of photographic connections between the molecules created in bulge points is also small. Distribution of potential energy of molecules in hardened layer is demonstrated on image 3,б. At enduring processing in water besides hardening of layer in nodes of standing wave there may occur local gelatin dissolution. In other words hydrated molecules get relatively free changing their structure but can’t leave the layer because of hardenings in bulge. Work [10] and [11] describe that gelatin structure change at processing in water as well as at it’s drying. Therefore when processed by isopropanol change of gelatin structure in nodes and bulges are realized different ways. At considerable loss of water molecules don’t have time to return to initial state so they are forced to create a new molecular netting different from that which is created at simple freezing or slow drying. Gelatin density decreases in bulge points of standing due to growth of layer volume and increases in bulges due to change of structure under influence of formed Cr (III). As a result gelatin loses its elasticity. Increased period of interference structure can also be registered in the layer. Increasing exposure involves increasing of potential energy modulation in swelled layer. Number of isophased surfaces recorded in layer increases (image 3, в,г,д). Width of spectrum reflection and displacement to red region decrease but diffraction efficiency increases. Performance of black-and-white image can be explained by change of gelatin structure. Unstructured spots cause considerable light dispersion and get milk-white colored. == Discussing results == Unusual properties of Lippmann’s photos made on gelatin plates can be used for producing selective glasses as well as for receiving pseudocolor slides from black-and-white negatives and image processing and registration. Possibility of using Lippmann’s photos as selective glasses follows directly from image 2. Length of wave reflection and half-width depend on exposure value. At this coefficient of reflection reaches 99% that allows using such glasses in laser resonators, interferometers Fabri-Perot and also as beam dividers in hologram devices. [[Image:LippmannFig3.jpg|center|Image 3. Scheme explaining dependence of interference structure on value of exposure: а - distribution of hardening in swelled non-exposed layer; б, в, г, д – modulation of hardening in swelled layer depending on exposure.]] They cost less than interference dielectric glasses. There is also possibility of producing glasses of almost any size as well as distribution of spectrum characteristics within glass plane. Pseudocolor slides received from black-and-white negatives may be used for transmission of graphic information for example schemes, tables, diagrams. Slides can be projected at passing light by simple slider as well as at reflected light by epidiascope. It’s better to give preference to the second variant as color gamma is fuller and image contrast is higher then. At printing from black-and-white negatives value H_max and H in equation (1) can be presented as <center><math>\displaystyle H_{max} = I_0 t (10^{-D_0})</math> and <math>\displaystyle H = I_0 t (10^{-D})</math></center> from this follows that change of color of Lippmann’s photo is linearly dependent on negative density. Last time in increasing frequency is used the idea of complex spacial distribution of different physical values by conventional colors for example at image digital processing [12]. This quality is inherent to Lippmann’s photos taking in consideration their nature. Lippmann’s coloring method has an advantage: such image may further be optically processed. Observing a pseudo-colored image through a light filter with gating line Δλ we can see details of initial image in the interval of densities ΔD. Details of interest of image may be marked by change of wave length of light filter. Diapason of densities may as well be marked by changing its half-width. If you make a photo of image observed through interference filter on a contrast photographic material you can receive image of lines of same density – equidensite. To illustrate this image of Jupiter was processed. For this the image of astro negative was printed with enlargement on dichromated gelatin plate. Then was made photo of received image through interference light filter with λ=640 nm and Δλ=90Å. Photo of initial image is presented on image 4, a. On image 4, б, в there are series of photos made at different angles of interference light filter incline that is at different λ and Δλ. You can see that even in conditions of incorrectly organized experiment (setting of wave length of light filter is realized by its incline) you can discover more details on received images than on initial negative. [[Image:LippmannFig4.jpg|center|Image 4. Marks of equidensite on Jupiter image: a – initial imprint of astro negative; б – photos of Lippmann’s image received using interference light filter at different angles of its incline at reflected light; в – the same but at passing light.]] At two-step process there inevitably occur distortion and noise at the first stage of registration. Grain on image 4, б is due to that of material on which the initial negative is registered. Therefore you can get much more information when processing Lippmann’s photos received at direct registration. Low sensitivity of dichromated gelatin plates does not allow direct registration of other astro objects except Sun. Direct registration of Lippmann’s photos is possible in biology. Radiation of ДРШ-250 lamp is enough for receiving images with enlargement 30-100x. Thus Lippmann’s photos received on dichromated gelatin plates using sources of monochromatic light have properties appreciably different from those of usual Lippmann’s photo. It’s related to properties of medium of registration. Period of fixed interference structure depends not only on length of radiation wave but also on its intensity. As a result there is a possibility to unambiguously transform light intensity to color. Simplicity of method of receiving Lippmann’s photos, possibility of using sources of low coherent length and high difraction efficiency offers a wide range of possibilities in practicing this method. In conclusion the author estimates as his pleasant duty to express gratitude to V.P.Sherstyuk, and L.E.Mazur for their important discussions, to V.A.Kaminskaya and L.E.Nikishyna for assistance in leading spectrophotometric measurement and to V.N.Dudinov for his kindly giving us astro negatives. == Literature: == # Lippmann G.C.R.// Acad. Sci. 1891.V.112. P. 274 # Kostylev G.D. // Letters in Technical Physics magazine 1976. T. 2. Edition 23.P. 1086. # Kostylev G.D., Ivanenko L.I. // Thesis report. IV All-Union conference “Photometry and its metrological equipment”. M., 1982. P. 119 # Sogokon A.B. // Thesis report. IV All-Union conference “Silverless and other unusual processes”. Chernogolovka, 1984. T. 1. Vol. 2. P. 125. # Sogokon A.B. // Thesis report. IV All-Union conference “Optical image formation and processing methods”. Kishinev, 1985. T. 1. P. 125. # Lin L.H. // Appl. Opt. 1969. V. 8. №5. P. 963. # Sjölinder S. // Photogr. Sci. and Eng. 1984. V. 28. №5. P. 180. # Nagorniy V.I., Chibisova N.P. // Successes of Physical Sciences. 1978. T. 19. P. 32. # Sherstyuk V.P., Dilung I.I. in “Fundamentals of optical memory and mediums”. Kiev: High School. 1982. Edition 13. P. 32 # Levi S.M., Suchkova O.M., Suvorin V.V. // Magazine of a scientific and applied photo and cinematography. 1984. T. 29. №4. P. 252 # Murzinov A.V., Moiseeva G.V., Stryukova E.G. and others // Thesis report at republican seminar “Applied holography”. Kiev, 1984. P. 49. # Usikov A. Y., Babichev A.A., Egorov A.D., and others // USSR Science Academy bulletin. 1977. №10. P. 47. Kharkov State University of Gorkiy 13.12.1985<br>Translated by Borozniak Evgeniy [[Category:Lippmann]] 78444563f9f9217e66b178542fe7903ac3e49b4e 1976 1975 2013-05-18T01:38:28Z Jsfisher 1 /* Method and results of experiment */ wikitext text/x-wiki = Lippmann’s photography on dichromated gelatin plate = Sogonkon' A. B. {{Note | This article was transcribed from the text in the [[Media : Sogokon Lipp phot on DCG.pdf | file available here]].}} The research of properties of Lippmann’s images obtained on dichromated gelatin plate shows that image color depends on wavelength of radiation as well as on its intensity. It relates to heterogeneous swelling of gelatin and structural changes of its unirradiated parts at fast dehydration. Unusual behaviour of Lippmann’s images on dichromated gelatin plate may be used for producing selective mirrors for reflecting graphic information and date registration and image processing. == Introduction == There is [1] a method of obtaining color image based on registration of standing waves in the volume of thick transparent photographic emulsion. Period of registered interference structure is unambiguously related to the length of the wave of radiation influencing the plate. This assures right color rendering of photographed image if disposed to white radiation. This method wasn't widely adopted because of big technical problems. Development of holography leads to creation of a totally new technique of experiment and new registering mediums. There appeared some announcements that Lippmann’s images have been tried on modern emulsions like ЛОИ-2 [2,3] and on dichromated gelatin [4,5]. The aim of this work is to investigate the behaviour of Lippmann’s images made on dichromated gelatin as well as mechanism of image formation and possibilities of its application on practice. == Method and results of experiment == Lippmann’s method is basic for making dichromated gelatin plates [6]. Holographic plates ПЭ-2 and ЛОИ-2 were placed into acid fixing solution then washed in running water and dried at room temperature. The plates were sensitized right before exposure. For this the plate was placed for 5-15 minutes into 1-5% solution of dichromated ammonium and after its runoff dried by hot air current at temperature 100-150°C. The duration of drying is 3-5 minutes. [[Image:LippmannFig1.jpg|center|Image 1. Scheme of device for contact printing of Lippmann’s images. 1 – light source (laser or mercury lamp), 2 – lens, 3 – negative, 4 - dichromated gelatin plate.]] Scheme of device for contact printing of Lippmann’s images is displayed on image 1. Widened laser beam is directed onto registering medium. The radiation passed through reflected from plate glass spreads in reverse and forms a standing wave in the volume of registering medium the amplitude of which depends of negative passing. As the source of radiation lasers ЛПМ-11(442nm) and ЛГИ-21 (337nm) and mercury lamp ДРШ-250 were used. Besides direct projecting printing of enlarged images was realized with help of a usual photographic enlarger. Processing mode of exposured plates hardly differed from that of dichromated gelatin for obtaining hologram [7]. Images obtained using the foregoing method have a number of interesting qualities. If watching at an image in reflected light (almost natural light rays falling) different parts of the image get different colors according to density of initial negative. The image gets blue color under transparent parts and red color under opaque ones. Half-tints of negative are reproduced by hues from orange to green. From this follows that interference structure period depends on length of radiation wave as well as on its intensity. A Lippmann’s image if placed on a black sheet of paper and watched at broad angle will be black-and-white. Gelatin remains transparent under transparent parts of the image and gets milkwhite under opaque parts. In this case the image is not reproduced by light absorption but its dispersion that resembles the properties of display on vesicular materials [8]. To investigate the dependence of image color on the exposure within one plate a number of exposures was done by collimated laser beam. There were made also photos of sensitometric wedge image and then spectrums of transmission of the received images measured. On image 2 there are spectral characteristics of images obtained on ПЭ-2 plates sensitized by 1% ammonium solution at exposure by laser ЛПМ-11 (image 2,a) and ЛГИ-21 (image 2, г). It follows from the analysis of spectrums that spectrum reflection width (image 2, e), length of wave maximum reflection (image 2, в) and density of image (image 2, б, д), change according to exposure amount. It is significant that length of wave maximum reflection at considerable exposure does not correspond to the length of radiation wave of the record. It’s due to increasing period of interference structure at layer processing. [[Image:LippmannFig2.jpg|center|Image 2. Lippmann’s images characteristics: а and г - dependence of image transmission spectrums on exposure amount at recording by radiation of helium-cadmium (442 nm) and nitrogen (337 nm) lasers; б and д – dependence of image density on exposure for the same wave length; в – dependence of image color on exposure logarithm (curve 1 – 442, curve 2 – 337 nm); dependence of half-width of transmission spectrums on exposure (1 – 442, 2 – 337 nm).]] Length of wave maximum reflection linearly depends on logarithm of exposure (image 2, в) what gives possibility to write <div> <p style="float: left; width: 90%; text-align: center;"><math>\displaystyle \lambda - \lambda_0 = k (\log{H_{max}} - \log{H})</math></p> <p style="float: left; width: 10%; text-align: center;">(1)</p> <p style="width: 100%;"></p> </div> where λo - length of wave maximum reflection at high energy of exposure (wave length of saturation), H – energy of exposure, k – coefficient of proportionality which may be interpreted as coefficient of colors contrast. Image color change evokes change of its density (image 2, б, д). These dependences are similar to characteristics curve of nigrescence of simple registering mediums. Nevertheless photographic width of linear region is much smaller. Dispersion of experimental points is especially considerable in regions of high exposure that can’t be explained by measurement errors. We can suppose that dependence of image transmission in region of saturation has oscillating character as demonstrated for example on image 2, д. == Mechanism of image creation == Preparing plates to sensitizing they should be placed into water for a period of time (about one hour). As a result gelatin gets swelled and long protein molecules swivel in the way to create linear chains. It relates more to molecules on the surface of the layer than those which are deep in as they are less exposed to strength of adjacent molecules. There appears a heterogeneous hardening increasing from the layer surface to substrate. Superficial gelatin molecules forming linear chains can no longer perform work as they took favorable energetic position. Molecules deep in the layer have some amount of potential energy. Their interaction with each other and molecules of gelatin hardener prevents their forming linear chains. This hardening can be defined as value inversely proportional to work performed by molecules when processed in water. The layer is not hardened if molecules realized their potential. The layer is hardened If they didn't realize their potential energy when processed in water. Distribution of potential energy in the thickness of hardened layer may be presented in diagram form as demonstrated on image 3,a. Let’s consider processes taking place at hardening of exposed layers. Here we consider that photochemical transformations Cr (VI) to Cr (III) is realized according to model described in work [9]. At low exposure energies the number of photographic connections between the molecules created in bulge points is also small. Distribution of potential energy of molecules in hardened layer is demonstrated on image 3,б. At enduring processing in water besides hardening of layer in nodes of standing wave there may occur local gelatin dissolution. In other words hydrated molecules get relatively free changing their structure but can’t leave the layer because of hardenings in bulge. Work [10] and [11] describe that gelatin structure change at processing in water as well as at it’s drying. Therefore when processed by isopropanol change of gelatin structure in nodes and bulges are realized different ways. At considerable loss of water molecules don’t have time to return to initial state so they are forced to create a new molecular netting different from that which is created at simple freezing or slow drying. Gelatin density decreases in bulge points of standing due to growth of layer volume and increases in bulges due to change of structure under influence of formed Cr (III). As a result gelatin loses its elasticity. Increased period of interference structure can also be registered in the layer. Increasing exposure involves increasing of potential energy modulation in swelled layer. Number of isophased surfaces recorded in layer increases (image 3, в,г,д). Width of spectrum reflection and displacement to red region decrease but diffraction efficiency increases. Performance of black-and-white image can be explained by change of gelatin structure. Unstructured spots cause considerable light dispersion and get milk-white colored. == Discussing results == Unusual properties of Lippmann’s photos made on gelatin plates can be used for producing selective glasses as well as for receiving pseudocolor slides from black-and-white negatives and image processing and registration. Possibility of using Lippmann’s photos as selective glasses follows directly from image 2. Length of wave reflection and half-width depend on exposure value. At this coefficient of reflection reaches 99% that allows using such glasses in laser resonators, interferometers Fabri-Perot and also as beam dividers in hologram devices. [[Image:LippmannFig3.jpg|center|Image 3. Scheme explaining dependence of interference structure on value of exposure: а - distribution of hardening in swelled non-exposed layer; б, в, г, д – modulation of hardening in swelled layer depending on exposure.]] They cost less than interference dielectric glasses. There is also possibility of producing glasses of almost any size as well as distribution of spectrum characteristics within glass plane. Pseudocolor slides received from black-and-white negatives may be used for transmission of graphic information for example schemes, tables, diagrams. Slides can be projected at passing light by simple slider as well as at reflected light by epidiascope. It’s better to give preference to the second variant as color gamma is fuller and image contrast is higher then. At printing from black-and-white negatives value H_max and H in equation (1) can be presented as <center><math>\displaystyle H_{max} = I_0 t (10^{-D_0})</math> and <math>\displaystyle H = I_0 t (10^{-D})</math></center> from this follows that change of color of Lippmann’s photo is linearly dependent on negative density. Last time in increasing frequency is used the idea of complex spacial distribution of different physical values by conventional colors for example at image digital processing [12]. This quality is inherent to Lippmann’s photos taking in consideration their nature. Lippmann’s coloring method has an advantage: such image may further be optically processed. Observing a pseudo-colored image through a light filter with gating line Δλ we can see details of initial image in the interval of densities ΔD. Details of interest of image may be marked by change of wave length of light filter. Diapason of densities may as well be marked by changing its half-width. If you make a photo of image observed through interference filter on a contrast photographic material you can receive image of lines of same density – equidensite. To illustrate this image of Jupiter was processed. For this the image of astro negative was printed with enlargement on dichromated gelatin plate. Then was made photo of received image through interference light filter with λ=640 nm and Δλ=90Å. Photo of initial image is presented on image 4, a. On image 4, б, в there are series of photos made at different angles of interference light filter incline that is at different λ and Δλ. You can see that even in conditions of incorrectly organized experiment (setting of wave length of light filter is realized by its incline) you can discover more details on received images than on initial negative. [[Image:LippmannFig4.jpg|center|Image 4. Marks of equidensite on Jupiter image: a – initial imprint of astro negative; б – photos of Lippmann’s image received using interference light filter at different angles of its incline at reflected light; в – the same but at passing light.]] At two-step process there inevitably occur distortion and noise at the first stage of registration. Grain on image 4, б is due to that of material on which the initial negative is registered. Therefore you can get much more information when processing Lippmann’s photos received at direct registration. Low sensitivity of dichromated gelatin plates does not allow direct registration of other astro objects except Sun. Direct registration of Lippmann’s photos is possible in biology. Radiation of ДРШ-250 lamp is enough for receiving images with enlargement 30-100x. Thus Lippmann’s photos received on dichromated gelatin plates using sources of monochromatic light have properties appreciably different from those of usual Lippmann’s photo. It’s related to properties of medium of registration. Period of fixed interference structure depends not only on length of radiation wave but also on its intensity. As a result there is a possibility to unambiguously transform light intensity to color. Simplicity of method of receiving Lippmann’s photos, possibility of using sources of low coherent length and high difraction efficiency offers a wide range of possibilities in practicing this method. In conclusion the author estimates as his pleasant duty to express gratitude to V.P.Sherstyuk, and L.E.Mazur for their important discussions, to V.A.Kaminskaya and L.E.Nikishyna for assistance in leading spectrophotometric measurement and to V.N.Dudinov for his kindly giving us astro negatives. == Literature: == # Lippmann G.C.R.// Acad. Sci. 1891.V.112. P. 274 # Kostylev G.D. // Letters in Technical Physics magazine 1976. T. 2. Edition 23.P. 1086. # Kostylev G.D., Ivanenko L.I. // Thesis report. IV All-Union conference “Photometry and its metrological equipment”. M., 1982. P. 119 # Sogokon A.B. // Thesis report. IV All-Union conference “Silverless and other unusual processes”. Chernogolovka, 1984. T. 1. Vol. 2. P. 125. # Sogokon A.B. // Thesis report. IV All-Union conference “Optical image formation and processing methods”. Kishinev, 1985. T. 1. P. 125. # Lin L.H. // Appl. Opt. 1969. V. 8. №5. P. 963. # Sjölinder S. // Photogr. Sci. and Eng. 1984. V. 28. №5. P. 180. # Nagorniy V.I., Chibisova N.P. // Successes of Physical Sciences. 1978. T. 19. P. 32. # Sherstyuk V.P., Dilung I.I. in “Fundamentals of optical memory and mediums”. Kiev: High School. 1982. Edition 13. P. 32 # Levi S.M., Suchkova O.M., Suvorin V.V. // Magazine of a scientific and applied photo and cinematography. 1984. T. 29. №4. P. 252 # Murzinov A.V., Moiseeva G.V., Stryukova E.G. and others // Thesis report at republican seminar “Applied holography”. Kiev, 1984. P. 49. # Usikov A. Y., Babichev A.A., Egorov A.D., and others // USSR Science Academy bulletin. 1977. №10. P. 47. Kharkov State University of Gorkiy 13.12.1985<br>Translated by Borozniak Evgeniy [[Category:Lippmann]] fc7c5a29ac3ec3f5c876511dc19ce46e3147d971 8 881 1977 2013-05-18T02:11:51Z Jsfisher 1 Created page with "HoloWiki &ndash; Information reference for Holoforums" wikitext text/x-wiki HoloWiki &ndash; Information reference for Holoforums 490fe51ff8d1042080e50cf7eda08ea6a918e0c4 1978 1977 2013-05-18T02:13:31Z Jsfisher 1 wikitext text/x-wiki HoloWiki homepage 6b782a6f97a9569ebb2d37011061b33212d95f50 1979 1978 2013-05-18T02:15:21Z Jsfisher 1 wikitext text/x-wiki Main page 97461b6c9e4e8749cbc57fafb28060bcbd15d377 0 193 1980 1615 2013-05-18T02:21:30Z Jsfisher 1 wikitext text/x-wiki [[Image:Colink.jpg]] Colin Kaminski is an amateur holographer who in a state of extreme frustration and needing advice started the forum that has become the [http://www.holographyforum.org Holography Forum] and then this Wiki. He really has no other holography related accomplishments other than about 100 or so 4x5" and smaller holograms given to children. He has worked as an Assembly Language Programmer, Motorcycle Mechanic, Luthier, Theatrical Lighting Designer, Product Designer and now he is the Master Brewer at [http://www.downtownjoes.com Downtown Joe's] in Napa, CA. [http://www.designerinlight.com Colin Kaminski's Web Site] [[Image:Colinemail.gif]] e5e8170494f69491986e3b08643052b2b953e021 4 882 1981 2013-05-18T02:45:15Z Jsfisher 1 Created page with "{{Note | Unless otherwise stated by the author the copyright for the HoloWiki will be GNU Public Documentation License as follows: | gotcha}} <big><big>'''GNU Free Documentat..." wikitext text/x-wiki {{Note | Unless otherwise stated by the author the copyright for the HoloWiki will be GNU Public Documentation License as follows: | gotcha}} <big><big>'''GNU Free Documentation License'''</big></big> <br>Version 1.3, 3 November 2008 Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. http://fsf.org/ Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. <big>'''0. 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If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software. d33b2fdbeaa6671900316d8c8a21e4c1e8fcb68f 4 883 1982 2013-05-18T04:01:30Z Jsfisher 1 Created page with "This wiki is the synthesis of the best efforts of its founder and subsequent administrators and contributors to bring to together interesting, significant, and accurate inform..." wikitext text/x-wiki This wiki is the synthesis of the best efforts of its founder and subsequent administrators and contributors to bring to together interesting, significant, and accurate information regarding holography. While reasonable efforts have been made to insure correctness in the articles provided, typographic errors, incomplete or incorrect information, or just bone-headed mistakes are still likely. Please use the information provided as guidance, not gospel, for what is truly a fascinating hobby, field of study, and professional endeavor. 7a0d6411ee951b956e1d6f8888b985911e076a12 1988 1982 2013-05-19T14:18:24Z Jsfisher 1 wikitext text/x-wiki This wiki is the synthesis of the best efforts of its founder and subsequent administrators and contributors to bring together interesting, significant, and accurate information regarding holography. While reasonable efforts have been made to insure correctness in the articles provided, typographic errors, incomplete or incorrect information, or just bone-headed mistakes are still likely. Please use the information provided as guidance, not gospel, for what is truly a fascinating hobby, field of study, and professional endeavor. 6f95e1128dbb5c332d304dd84afdebcf4aa03739 0 875 1983 1964 2013-05-18T20:21:34Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[8_LAJPE_525_Ramon_Gomez_Preprint_corr_f.pdf | Low cot instrumentation for spin-coating deposition of thin films in an undergraduate laboratory]]''', Ramon Gómez Aguilar, Jaime Ortiz López. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * '''[[Media:grains.pdf | Silver Halide Materials]],''' Dinesh Padivar. (The "grains.pdf" document.) * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. 8d364156cc603a9d05d7be7d33ea30db02a1809e 1984 1983 2013-05-18T20:22:07Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:8_LAJPE_525_Ramon_Gomez_Preprint_corr_f.pdf | Low cot instrumentation for spin-coating deposition of thin films in an undergraduate laboratory]]''', Ramon Gómez Aguilar, Jaime Ortiz López. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * '''[[Media:grains.pdf | Silver Halide Materials]],''' Dinesh Padivar. (The "grains.pdf" document.) * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. 3acb1e849ee1d39bf5e206b2a325a3c5fcb35618 1986 1984 2013-05-19T01:56:34Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:8_LAJPE_525_Ramon_Gomez_Preprint_corr_f.pdf | Low cot instrumentation for spin-coating deposition of thin films in an undergraduate laboratory]]''', Ramon Gómez Aguilar, Jaime Ortiz López. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * '''[[Media:grains.pdf | Silver Halide Materials]],''' Dinesh Padivar. (The "grains.pdf" document.) * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. * '''[[Media:Kock-LasersHolography.pdf | Lasers and Holography]],''' William Kock. 680a3aaa90913d9d8dc5863e23aee02b0da2aed3 6 884 1985 2013-05-18T20:22:21Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 885 1987 2013-05-19T01:56:53Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 1 886 1989 2013-05-24T02:27:23Z Jsfisher 1 Created page with "I have attempted to make this a bit more friendly to new-comers. Dropping them into just an FAQ seemed abrupt; I'm hopeful a little historical text and "you can do it to" enc..." wikitext text/x-wiki I have attempted to make this a bit more friendly to new-comers. Dropping them into just an FAQ seemed abrupt; I'm hopeful a little historical text and "you can do it to" encouragement might be more positive. /JSFisher 9a9af65bf29d82417484243b82b72cd87448701f 0 820 1990 1916 2013-05-24T03:45:23Z Jsfisher 1 /* Overview of the Process */ wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. They are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. Epoxy is normal sealant. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html [[Category:DCG]] [[Category:Beginner]] df7200fb1128d1c72693c0ea1d6dd201daa8cf98 1991 1990 2013-05-24T03:49:28Z Jsfisher 1 /* Overview of the Process */ wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. They are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. A common method to seal the hologram is to epoxy a second glass plate to the back of the hologram plate, thereby protecting it from moisture. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html [[Category:DCG]] [[Category:Beginner]] e49f1f2ed77f5f358d6d777198555c084a2b96e9 0 489 1992 1909 2013-05-25T01:33:52Z Jsfisher 1 wikitext text/x-wiki http://abc.def.com/asdf Text <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4444ff;" width="50%" |- | [[Image:HoloforumLogo.gif | left]] <big>holoforum.org</big><br>A place to discuss holography |} This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y}</math> <math>\textstyle \frac{x}{y}</math> <math>\scriptstyle \frac{x}{y}</math> <math>\scriptscriptstyle \frac{x}{y}</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> 9f3381b213f2dc84f2c999fb8dc34e30e073c4d5 1994 1992 2013-05-25T01:55:30Z Jsfisher 1 wikitext text/x-wiki http://abc.def.com/asdf Text <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4444ff;" width="50%" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y} scriptscriptstyle</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> a3beac1e5dd85ef2ed2b066253bee75d3a075d0d 1995 1994 2013-05-25T02:03:16Z Jsfisher 1 wikitext text/x-wiki http://abc.def.com/asdf Text <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y} scriptscriptstyle</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. 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wikitext text/x-wiki A temperature stabilized laser diode a3e9858c28a332e1188c245870b8d6174cecfb9a 6 373 2065 874 2013-05-25T03:06:11Z Jsfisher 1 Jsfisher uploaded &quot;[[File:Temp Controlled Diode Laser.JPG]]&quot;: MsUpload wikitext text/x-wiki How it looks. :) aaec8421cdb668a79950c02d258c6c1e5a32b1c1 6 375 2066 878 2013-05-25T03:06:12Z Jsfisher 1 Jsfisher uploaded &quot;[[File:TheEye.gif]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 376 2067 880 2013-05-25T03:06:13Z Jsfisher 1 Jsfisher uploaded &quot;[[File:Top View.jpg]]&quot;: MsUpload wikitext text/x-wiki Top view 9d597493304aed540ed1f806581a50f570082497 6 377 2068 882 2013-05-25T03:06:14Z Jsfisher 1 Jsfisher uploaded &quot;[[File:Top View1.jpg]]&quot;: MsUpload wikitext text/x-wiki Top View e800176ba71bf1fe8e9abff8def5e052dfc9da34 6 379 2069 894 2013-05-25T03:06:15Z Jsfisher 1 Jsfisher uploaded &quot;[[File:VeilFig1.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 380 2070 896 2013-05-25T03:06:15Z Jsfisher 1 Jsfisher uploaded &quot;[[File:VeilFig2.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 381 2071 898 2013-05-25T03:06:16Z Jsfisher 1 Jsfisher uploaded &quot;[[File:VeilFig3.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 382 2072 900 2013-05-25T03:06:17Z Jsfisher 1 Jsfisher uploaded &quot;[[File:VeilFig4.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 383 2073 902 2013-05-25T03:06:18Z Jsfisher 1 Jsfisher uploaded &quot;[[File:VeilFig5.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 384 2074 904 2013-05-25T03:06:18Z Jsfisher 1 Jsfisher uploaded &quot;[[File:VeilFig6.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 385 2075 906 2013-05-25T03:06:19Z Jsfisher 1 Jsfisher uploaded &quot;[[File:VeilFig7.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 386 2076 908 2013-05-25T03:06:20Z Jsfisher 1 Jsfisher uploaded &quot;[[File:VeilFig8.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 388 2077 916 2013-05-25T03:06:21Z Jsfisher 1 Jsfisher uploaded &quot;[[File:WaveSelectAndEtalon.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 390 2078 920 2013-05-25T03:06:22Z Jsfisher 1 Jsfisher uploaded &quot;[[File:WholeLaser.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 889 2079 2013-05-25T03:06:22Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 890 2080 2013-05-25T03:06:24Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 291 2081 466 2013-05-25T03:14:52Z Jsfisher 1 Jsfisher uploaded &quot;[[File:C532.200sm.jpg]]&quot; wikitext text/x-wiki Image from Sam´s Laserfaq http://www.laserfaq.org/sam/c532cav1.jpg b88b4c2de2f083995b26aaee93f48a2ae396e19d 1 537 2082 1225 2013-05-25T03:18:46Z Jsfisher 1 wikitext text/x-wiki Colin, I don't know how to delete and uploaded file. So I had to re-upload this one and named it "PreScoredCoatAtOnce2.JPG". Could you delete the original named "PreScoredCoatAtOnce.JPG" and explain how to delete an uploaded file. I do not want to waste space on the server. John P. ---- Hi John, if you have the image showing, click on the image. There is a button for deleting it. I don't really know why we can save a new image to an old name, it is not a reported bug with this version. It likely has to do with the security settings... BTW, nice work! I deleted it... 8fd0ecdfa8831496503b7b7dec89087278d16294 0 869 2083 1939 2013-05-25T03:23:42Z Jsfisher 1 /* People */ wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.gif | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Kaveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:RudieBerkhout.jpg | [[Rudie Berkhout]] File:HBjelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:CardinSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | [[Bernard Cole]] File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Cross, Lloyd | Lloyd Cross]] File:MichaelHDag.jpg | Somebody "Michael H Dag" File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavolora.jpg | [[Gregg E. Favalora]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:Harrison.jpg | [[Michael Harrison]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:GLippmann.jpg | Jonas Ferdinand [[Gabriel Lippmann]] File:Kaufmna.jpg | [[John Kaufman]] File:Lakes.jpg | [[Roderic Lakes]] File:Leith.jpg | [[Emmett Leith]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody M Mueller File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:FB_Rallison.jpg | [[Rallison, Richard | Richard D. Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody H Silver File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] file:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | Somebody RDRJack84 File:RDRJerry83.jpg | Somebody RDRJerry83 File:RDRLloyd.jpg | Somebody RDRLloyd File:RLakes.jpg | Somebody R Lakes File:RDRMikef.jpg | Somebody RDRMikef File:RDRPosyoffice76.jpg | Somebody RDRPosyoffice76 File:RDRRdraust.jpg | Somebody RDRRdraust File:RDRRick.jpg | Somebody RDRRick File:RDRSpike.jpg | Somebody RDRSpike File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> d2f7d6025d854fab2e0b80b09c1aae0e0c3a6993 2084 2083 2013-05-25T03:34:55Z Jsfisher 1 /* People */ wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.gif | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Kaveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:RudieBerkhout.jpg | [[Rudie Berkhout]] File:HBjelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:HSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | [[Bernard Cole]] File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Cross, Lloyd | Lloyd Cross]] File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavalora.jpg | [[Gregg E. Favalora]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:MichaelHDag.jpg | [[Michael Harrison]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:GLippmann.jpg | Jonas Ferdinand [[Gabriel Lippmann]] File:Kaufmna.jpg | [[John Kaufman]] File:RLakes.jpg | [[Roderic Lakes]] File:Leith.jpg | [[Emmett Leith]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody M Mueller File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:FB_Rallison.jpg | [[Rallison, Richard | Richard D. Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody H Silver File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] file:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | Somebody RDRJack84 File:RDRJerry83.jpg | Somebody RDRJerry83 File:RDRLloyd.jpg | Somebody RDRLloyd File:RDRMikef.jpg | Somebody RDRMikef File:RDRPosyoffice76.jpg | Somebody RDRPosyoffice76 File:RDRRdraust.jpg | Somebody RDRRdraust File:RDRRick.jpg | Somebody RDRRick File:RDRSpike.jpg | Somebody RDRSpike File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> fec8d2648e4c1fd89a7198b8cd9a7ef5f4719752 2110 2084 2013-05-27T02:10:13Z Jsfisher 1 wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.gif | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Kaveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:RudieBerkhout.jpg | [[Rudie Berkhout]] File:HBjelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:HSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | [[Bernard Cole]] File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Cross, Lloyd | Lloyd Cross]] File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavalora.jpg | [[Gregg E. Favalora]] File:RDRMikef.jpg | [[Mike Foster]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:MichaelHDag.jpg | [[Michael Harrison]] File:RDRJerry83.jpg | [[Jerry Heidt]] File:RDRPosyoffice76.jpg | [[Rosemary Jackson]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:Kaufmna.jpg | [[John Kaufman]] File:RLakes.jpg | [[Roderic Lakes]] File:RDRHarry.jpg | [[Harry Knowles]] File:Leith.jpg | [[Emmett Leith]] File:GLippmann.jpg | Jonas Ferdinand [[Gabriel Lippmann]] File:RDRRick.jpg | [[Rick Lowe]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | Somebody M Mueller File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:FB_Rallison.jpg | [[Rallison, Richard | Richard D. Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody H Silver File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] File:RDRSpike.jpg | [[Spike Stewart]] File:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | [[Jack Worthington]] File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> 480fbd5d6511206e3603e43ed286829ce8c311bf 6 891 2085 2013-05-25T04:12:03Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 588 2086 1849 2013-05-25T04:18:04Z Jsfisher 1 /* Dave Battin's Article on Veil Coating */ wikitext text/x-wiki Veil Coating ==Veil Coating - Part I== The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70F.) Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45 degree angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. ===Post Spinning - Part IIa=== Take the plate and immediately place it on a turn table and spin it as 78 RPM’s. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. ===Post Leaning/Lying - Part IIb=== If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. ===Re-Using Emulsion - Part III=== If you run out of emulsion in the pouring container while coating, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. Allow the emulsion to come back up to coating temperature of 110 to 120F. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. Although refilter does not have to be done during one session if things are kept clean, I suggest refiltering after refrigerating and re-cooking. ==Dave Battin's Article on Veil Coating== Having tried all the methods available to most hobby holographers, I've found the best method for me is the veil coat method. I have attached a still shot to give you a preview to this method, and I plan on showing a step by step instructions so all should be able to coat easily. please see the video clip at the bottom of this page to see this method in action, sorry for the weird color ,as im actually making DCG film under a yellow/red safelite [[Image:VeilFig1.jpg]] The size of the glass is 4"x16" if i trim off one inch the top it will yield me Three nice 4x5s. When acquiring glass I have found a great source is at your local art store, the type that has a special every week, (here its called Michael's), Its the replacement glass sold for picture frames, located in or near the framing department. It comes cleaned sealed and slightly lighter/weight than the regular 1/8" glass found at the local hardware store. The largest I can get is 16"x20" for @ $5 each, not bad for coming cleaned and ready to cut .................. subbing will be next [[Image:VeilFig2.jpg]] I have found it much easier to cut the glass into 4”x16” pieces before subbing. [[Image:VeilFig3.jpg]] A simple jig to cut your glass will give you nice consistent cuts every time. By banking your glass to the stop and placing the proper width spacer on top, simply bank your glass cutter against the spacer and slice. It’s best to provide a little lubricant to help the cut a little (I lick the cutter first). Now that my glass is cut, I'll prep the surface for coating. This glass is pretty clean already. If you’re unsure, I would soak it in a 20% Clorox Solution (soak over night), and after a quick water wash, soak in the Cascade (dishwasher soap) and water mix (I use a small handful for 2 gallons of water or so) again soak overnight after a slight scrubbing action using a plastic scrubby pad. [[Image:VeilFig4.jpg]] After removal of the glass from the Cascade, I give it a quick dip into clean water and then a final plunge into what they refer to as (Trisodium Phosphate) substitute. Where I live, they won’t allow the use of the real TSP, as it’s bad for the ground water. Allow to dry by leaning on wall, sitting on a paper towel. [[Image:VeilFig5.jpg]] The glass is now ready to be coated, but we must add a few extra items to make things easier later on ………………………… [[Image:VeilFig6.jpg]] Well, the glass is almost ready to coat. We will have to attach a few pieces of tape and paper to make this work correctly. [[Image:VeilFig7.jpg]] I do all the work under my laminar flow booth. It helps to place your plate (the glass will now be referred to as plate) on some type of pedestal (as shown) or block of wood. (photo A) Start by placing the plate face down on the pedestal and applying plain old ordinary scotch tape to both long sides of plate, adhere tape directly to the back of the plate, allowing only half of the tape to hang off the sides the entire length of the plate (photo B). I call these gutters. These will allow you to coat your plate up to the very edge without any waste. Once the gutters are in place, turn your plate face up, and again place on the pedestal. Now using a short piece of tape slightly longer than the width of your plate, attach it to the top, adhering directly onto the face of the plate, again leaving half the tape to hang off the top (photo C). Now that the top tape is adhered, we will now apply the “Tab”, a small 1x5 inch piece of paper applied from the back of the plate stuck to the tape along the top. This tab will be used numerous times throughout the operation so be sure its adhered well (photo D). Your plate should now look like this: [[Image:VeilFig8.jpg]] The paper tab I attached to the top of the plate, will now act as a handle and I can hold it while doing a final cleaning, I lay the glass across my leg and wipe it clean (front only)using a folded paper towel and simple Windex glass cleaner ,always spray on the towel and not the glass! With my method of coating I felt to lean is to be constant! The angle of incline is not so important, but its to always repeat the same angle, I achieve this by placing the plate in a holding jig, see the video to help explain, the film is now ready for coating . A few minuets after coating , the paper tab will now allow you to attach a large paper clip, and hang your film to dry. By using a lab base and thin rod clamped horizontally, its easy to hang 12 4x5s to dry! The blow dryer I use is old and weak! But it has two settings hi/low heat, at low it is very weak (blowing), and you will see me blowing close to the wet emulsion. Most new blow dryers will be way to powerful for this. To apply the emulsion I use a simple squirt bottle, very easy to regulate flow, with the current bottle, I can coat three 4x16 plate before I have to recharge the bottle. [[Media:coatmeth.wmv | Dave Battin's Coating Video]] [http://www.youtube.com/watch?v=b0Toqidt0eo Dave Battin's Coating Video on YouTube] 522d77dc029c9d98ca4f0f1ef07bf11ad2539bf6 6 391 2087 922 2013-05-26T03:32:26Z Jsfisher 1 Jsfisher uploaded &quot;[[File:Woodgrain.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 289 2088 462 2013-05-26T03:32:27Z Jsfisher 1 Jsfisher uploaded &quot;[[File:BurnOut.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 299 2089 502 2013-05-26T03:32:28Z Jsfisher 1 Jsfisher uploaded &quot;[[File:Drippy.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 352 2090 790 2013-05-26T03:32:29Z Jsfisher 1 Jsfisher uploaded &quot;[[File:ObjectMovement2.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 354 2091 802 2013-05-26T03:32:29Z Jsfisher 1 Jsfisher uploaded &quot;[[File:PlateMovement.jpg]]&quot;: MsUpload wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 378 2092 892 2013-05-26T03:41:37Z Jsfisher 1 Jsfisher uploaded &quot;[[File:UnderExposed.jpg]]&quot; wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 892 2093 2013-05-26T22:13:02Z Jsfisher 1 Created page with "This is a collection of simple tips and techniques worth sharing. == DCG == ==== Effect of Overexposure ==== {| | [[Image:DCGdiffeff.jpg | right]] Overexposure can have a dra..." wikitext text/x-wiki This is a collection of simple tips and techniques worth sharing. == DCG == ==== Effect of Overexposure ==== {| | [[Image:DCGdiffeff.jpg | right]] Overexposure can have a drastic effect on dichromated gelatin. Test strips early and often are well advised. The graph is from ''Lasers and Holography'' by Mehta and Rampal, 1993. It was reprinted from a paper by Chang and Leonard, "Dichromated gelatin for the fabrication of holographic optical elements," ''Applied Optics'', 1979. |} a5842289c7501cff6fdc020b8b915695d9f96b98 2095 2093 2013-05-26T22:23:52Z Jsfisher 1 wikitext text/x-wiki This is a collection of simple tips and techniques worth sharing. == DCG == ==== Effect of Overexposure ==== {| | [[Image:DCGdiffeff.jpg | 400px | right]] Overexposure can have a drastic effect on dichromated gelatin. Test strips early and often are well advised. The graph is from ''Lasers and Holography'' by Mehta and Rampal, 1993. It was reprinted from a paper by Chang and Leonard, "Dichromated gelatin for the fabrication of holographic optical elements," ''Applied Optics'', 1979. http://holoforum.org/forum/viewtopic.php?f=7&t=652 |} bad9dae1926cb6bc0541b230dc242bb5f57c970e 2098 2095 2013-05-27T00:05:24Z Jsfisher 1 wikitext text/x-wiki This is a collection of simple tips and techniques worth sharing. == Darkroom == == Silver-halide == == DCG == ==== Effect of Overexposure ==== {| | [[Image:DCGdiffeff.jpg | 400px | right]] adapted from a post by Joe Farina, http://holoforum.org/forum/viewtopic.php?f=7&t=652 Overexposure can have a drastic effect on dichromated gelatin. Test strips early and often are well advised. The graph is from ''Lasers and Holography'' by Mehta and Rampal, 1993. It was reprinted from a paper by Chang and Leonard, "Dichromated gelatin for the fabrication of holographic optical elements," ''Applied Optics'', 1979. |} ==== Boiling holograms ==== {| | {| style="float: right;" | [[Image:bb1.jpg | 250px | Buddha before boiling]] |- | [[Image:bb2.jpg | 250px | Buddha after boiling]] |} adapted from a post by manalokos, http://holoforum.org/forum/viewtopic.php?f=7&t=138 I was frustrated with a hologram of a tiny buddha statue because it was dim and narrow-band, shifting a bit too much to the blue. I heated water until it boiled, took it out of the heat source, and then dropped the plate inside, left it there for 60 seconds, and put it into ambient temp water. I re-developed it, and I got a much more broadband and brighter result. |} 8c5375364db3123fb83de794aadbf61e07b17a82 2099 2098 2013-05-27T00:13:27Z Jsfisher 1 wikitext text/x-wiki This is a collection of simple tips and techniques worth sharing. == Darkroom == == Optics == === Rotating Polarization with Mirrors === [[PolarizRotateWMirror.jpg]] == Silver-halide == == DCG == ==== Effect of Overexposure ==== {| | [[Image:DCGdiffeff.jpg | 400px | right]] adapted from a post by Joe Farina, http://holoforum.org/forum/viewtopic.php?f=7&t=652 Overexposure can have a drastic effect on dichromated gelatin. Test strips early and often are well advised. The graph is from ''Lasers and Holography'' by Mehta and Rampal, 1993. It was reprinted from a paper by Chang and Leonard, "Dichromated gelatin for the fabrication of holographic optical elements," ''Applied Optics'', 1979. |} ==== Boiling holograms ==== {| | {| style="float: right;" | [[Image:bb1.jpg | 250px | Buddha before boiling]] |- | [[Image:bb2.jpg | 250px | Buddha after boiling]] |} adapted from a post by manalokos, http://holoforum.org/forum/viewtopic.php?f=7&t=138 I was frustrated with a hologram of a tiny buddha statue because it was dim and narrow-band, shifting a bit too much to the blue. I heated water until it boiled, took it out of the heat source, and then dropped the plate inside, left it there for 60 seconds, and put it into ambient temp water. I re-developed it, and I got a much more broadband and brighter result. |} 97da71df1090bd51e0f21375f962b35617e7f5c6 2100 2099 2013-05-27T00:16:51Z Jsfisher 1 wikitext text/x-wiki This is a collection of simple tips and techniques worth sharing. == Darkroom == == Optics == === Rotating Polarization with Mirrors === [[Image:PolarizRotateWMirrors.jpg]] == Silver-halide == == DCG == ==== Effect of Overexposure ==== {| | [[Image:DCGdiffeff.jpg | 400px | right]] adapted from a post by Joe Farina, http://holoforum.org/forum/viewtopic.php?f=7&t=652 Overexposure can have a drastic effect on dichromated gelatin. Test strips early and often are well advised. The graph is from ''Lasers and Holography'' by Mehta and Rampal, 1993. It was reprinted from a paper by Chang and Leonard, "Dichromated gelatin for the fabrication of holographic optical elements," ''Applied Optics'', 1979. |} ==== Boiling holograms ==== {| | {| style="float: right;" | [[Image:bb1.jpg | 250px | Buddha before boiling]] |- | [[Image:bb2.jpg | 250px | Buddha after boiling]] |} adapted from a post by manalokos, http://holoforum.org/forum/viewtopic.php?f=7&t=138 I was frustrated with a hologram of a tiny buddha statue because it was dim and narrow-band, shifting a bit too much to the blue. I heated water until it boiled, took it out of the heat source, and then dropped the plate inside, left it there for 60 seconds, and put it into ambient temp water. I re-developed it, and I got a much more broadband and brighter result. |} 3af05b09aa1580c0351a6e1e8afba79d35ece742 2101 2100 2013-05-27T00:22:13Z Jsfisher 1 wikitext text/x-wiki This is a collection of simple tips and techniques worth sharing. == Darkroom == == Optics == === Rotating Polarization with Mirrors === {| | [[Image:PolarizRotateWMirrors.jpg | right]] This image is self explanitory on how to rotate the polarization of the laser beam with two front surface steerable mirrors. This was taken directly from Kaveh's Thesis with his permission. |} == Silver-halide == == DCG == ==== Effect of Overexposure ==== {| | [[Image:DCGdiffeff.jpg | 400px | right]] adapted from a post by Joe Farina, http://holoforum.org/forum/viewtopic.php?f=7&t=652 Overexposure can have a drastic effect on dichromated gelatin. Test strips early and often are well advised. The graph is from ''Lasers and Holography'' by Mehta and Rampal, 1993. It was reprinted from a paper by Chang and Leonard, "Dichromated gelatin for the fabrication of holographic optical elements," ''Applied Optics'', 1979. |} ==== Boiling holograms ==== {| | {| style="float: right;" | [[Image:bb1.jpg | 250px | Buddha before boiling]] |- | [[Image:bb2.jpg | 250px | Buddha after boiling]] |} adapted from a post by manalokos, http://holoforum.org/forum/viewtopic.php?f=7&t=138 I was frustrated with a hologram of a tiny buddha statue because it was dim and narrow-band, shifting a bit too much to the blue. I heated water until it boiled, took it out of the heat source, and then dropped the plate inside, left it there for 60 seconds, and put it into ambient temp water. I re-developed it, and I got a much more broadband and brighter result. |} 94fbf1936af959b94f2568388573670c431f8129 2105 2101 2013-05-27T00:43:19Z Jsfisher 1 wikitext text/x-wiki This is a collection of simple tips and techniques worth sharing. == Darkroom == == Optics == === Rotating Polarization with Mirrors === {| | [[Image:PolarizRotateWMirrors.jpg | right]] This image is self explanitory on how to rotate the polarization of the laser beam with two front surface steerable mirrors. This was taken directly from [[Media:kaveh-PhD.pdf | Kaveh's Thesis]] with his permission. |} == Silver-halide == == DCG == ==== Effect of Overexposure ==== {| | [[Image:DCGdiffeff.jpg | 400px | right]] adapted from a post by Joe Farina, http://holoforum.org/forum/viewtopic.php?f=7&t=652 Overexposure can have a drastic effect on dichromated gelatin. Test strips early and often are well advised. The graph is from ''Lasers and Holography'' by Mehta and Rampal, 1993. It was reprinted from a paper by Chang and Leonard, "Dichromated gelatin for the fabrication of holographic optical elements," ''Applied Optics'', 1979. |} ==== Boiling holograms ==== {| | {| style="float: right;" | [[Image:bb1.jpg | 250px | Buddha before boiling]] |- | [[Image:bb2.jpg | 250px | Buddha after boiling]] |} adapted from a post by manalokos, http://holoforum.org/forum/viewtopic.php?f=7&t=138 I was frustrated with a hologram of a tiny buddha statue because it was dim and narrow-band, shifting a bit too much to the blue. I heated water until it boiled, took it out of the heat source, and then dropped the plate inside, left it there for 60 seconds, and put it into ambient temp water. I re-developed it, and I got a much more broadband and brighter result. |} d7fd533a5f84fd7e727af5ad4b346a87b8cec45d 2111 2105 2013-05-27T04:08:33Z Jsfisher 1 /* Silver-halide */ wikitext text/x-wiki This is a collection of simple tips and techniques worth sharing. == Darkroom == == Optics == === Rotating Polarization with Mirrors === {| | [[Image:PolarizRotateWMirrors.jpg | right]] This image is self explanitory on how to rotate the polarization of the laser beam with two front surface steerable mirrors. This was taken directly from [[Media:kaveh-PhD.pdf | Kaveh's Thesis]] with his permission. |} == Silver-halide == === Defogger === adapted from the thread http://holoforum.org/forum/viewtopic.php?f=9&t=215 PBU (Phillips - Bjelkhagen Ultimate) bleach makes a good film defogger * 10 g Potassium persulfate * 10 g Sodium bisulfate (or citric acid) * 20 g Potassium bromite * 1 g Cupric bromide * 1 g Amidol (or Metol) To use it as defogging solution, pH must be raised first, otherwise the sensitizing dyes will be deactivated. (This is true at least for the PFG-03C dyes.) Diluted it 1:10 parts water, then raise the pH to 5.6 by adding drops of 10% sodium hydroxide. Soak the plates for 1 minute in the solution, then rinse and allow to dry. == DCG == ==== Effect of Overexposure ==== {| | [[Image:DCGdiffeff.jpg | 400px | right]] adapted from a post by Joe Farina, http://holoforum.org/forum/viewtopic.php?f=7&t=652 Overexposure can have a drastic effect on dichromated gelatin. Test strips early and often are well advised. The graph is from ''Lasers and Holography'' by Mehta and Rampal, 1993. It was reprinted from a paper by Chang and Leonard, "Dichromated gelatin for the fabrication of holographic optical elements," ''Applied Optics'', 1979. |} ==== Boiling holograms ==== {| | {| style="float: right;" | [[Image:bb1.jpg | 250px | Buddha before boiling]] |- | [[Image:bb2.jpg | 250px | Buddha after boiling]] |} adapted from a post by manalokos, http://holoforum.org/forum/viewtopic.php?f=7&t=138 I was frustrated with a hologram of a tiny buddha statue because it was dim and narrow-band, shifting a bit too much to the blue. I heated water until it boiled, took it out of the heat source, and then dropped the plate inside, left it there for 60 seconds, and put it into ambient temp water. I re-developed it, and I got a much more broadband and brighter result. |} ea8d4f0c2dd1feffeaff3fefdeeab3e0e9218b52 6 893 2094 2013-05-26T22:13:55Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 894 2096 2013-05-26T23:56:42Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 895 2097 2013-05-26T23:57:05Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 875 2102 1986 2013-05-27T00:40:06Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:8_LAJPE_525_Ramon_Gomez_Preprint_corr_f.pdf | Low cot instrumentation for spin-coating deposition of thin films in an undergraduate laboratory]]''', Ramon Gómez Aguilar, Jaime Ortiz López. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * '''[[Media:grains.pdf | Silver Halide Materials]],''' Dinesh Padivar. (The "grains.pdf" document.) * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. * '''[[Media:Kock-LasersHolography.pdf | Lasers and Holography]],''' William Kock. * '''[[Media:kaveh-PhD.pff | Techniques in Display Holography]],''' Kaveh Bazargan, PhD thesis, University of London, April 1986. 0c48c390a8070aec34af0520944c827f6c89c159 2103 2102 2013-05-27T00:40:54Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:8_LAJPE_525_Ramon_Gomez_Preprint_corr_f.pdf | Low cot instrumentation for spin-coating deposition of thin films in an undergraduate laboratory]]''', Ramon Gómez Aguilar, Jaime Ortiz López. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * '''[[Media:grains.pdf | Silver Halide Materials]],''' Dinesh Padivar. (The "grains.pdf" document.) * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. * '''[[Media:Kock-LasersHolography.pdf | Lasers and Holography]],''' William Kock. * '''[[Media:kaveh-PhD.pdf | Techniques in Display Holography]],''' Kaveh Bazargan, PhD thesis, University of London, April 1986. 9ba12b6a8b13a858259f232f8fd30d573d9e5c62 6 896 2104 2013-05-27T00:41:25Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 1 2106 1963 2013-05-27T00:46:27Z Jsfisher 1 wikitext text/x-wiki Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms. {{Note | This wiki is undergoing a slow and painful face lift. Please bear with us.| gotcha}} [[File:Olympic.jpg|250px|right|Hologram by Tom B. The Gallery has a stereographic pair version.]] * '''[[Gallery]].''' Great examples of success, failure, and experiments. * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * [[Archives|Archives]] * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). c3c151426aa83ec6ad7d4d3609751b899b1e5058 2108 2106 2013-05-27T01:42:51Z Jsfisher 1 wikitext text/x-wiki [[File:Olympic.jpg|250px|right|Hologram by Tom B. The Gallery has a stereographic pair version.]] <big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big> === Basic Information === * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. === A Little History === * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. === Advanced Information === * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. === Other Resources === * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). <!-- * [[Archives|Archives]] --> 20a0288ee46b33efa455b8924d8145b3a1864b5c 2109 2108 2013-05-27T01:53:33Z Jsfisher 1 wikitext text/x-wiki [[File:Olympic.jpg|250px|right|Hologram by Tom B. The Gallery has a stereographic pair version.]] <big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big> === Basic Information === * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. === A Little History === * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. === Advanced Information === * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. === Other Resources === * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). <!-- * [[Archives|Archives]] --> 594c3056daf7ba83fc5b9cc84b025052e0b2f6ca 2112 2109 2013-05-27T04:15:09Z Jsfisher 1 wikitext text/x-wiki <big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big> {| class="wikitable" style="float: right; color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. === Basic Information === * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. === A Little History === * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. === Advanced Information === * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. === Other Resources === * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). <!-- * [[Archives|Archives]] --> b89d0fd4bce4c9d029b5ff05fac07d632f84c52d 2113 2112 2013-05-27T04:20:30Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="float: right; color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). <!-- * [[Archives|Archives]] --> 39a4848d320a2bb20dadbf3a1d02de08676284c2 14 860 2107 1868 2013-05-27T01:00:52Z Jsfisher 1 wikitext text/x-wiki Richard Rallison was a pioneer in exploring the use of dichromated gelatin in holography. He chronicled many of his findings and wisdom on the Ralcon Development Labs web site. With Ralcon Development Labs no longer in operation, and with the untimely death of Rallison, his postings might have been lost forever had it not been for the [http://archive.org/web/web.php Internet Archive Wayback Machine]. Articles indexed below were retrieved from the Wayback Machine. 9cf141605aa7957e2836d80d8e64361ea07eeaa3 0 839 2114 1759 2013-05-27T23:52:29Z Jsfisher 1 /* Refractive index change as a function o fdepth for 901 points */ wikitext text/x-wiki [[File:deltan.gif|center|Exposure vs. density]] {| border=1 |- | Material || DCG || DMP128 || PVK |- | Sensitivity (mj/cm²) || 2-100 @ 442-532 || 30 @ 633-694 || 20 @ 488-532 |- | Approximate available index mod (Delta n) || 0.25 || 0.20 || 0.20 |- | Max O.D. attained in notch filters || 5 || 4 || 2.5 |- | Useful thickness range (microns) || 5-25 || 7-15 || 5-10 |- | Available Spectral Bandwidths (nm) || 10-150 || 10-100 || 20-100 |- | Playback compared to record wavelength || red shift for broad and/or blue shift for narrow | variable blue shift || red broad/blue narrow |- | Minimum recommended protection || 40 mil glass and epoxy || 4 mil Aclar || 4 mil mylar |- | Resistance to water || poor || fair || excellent |- | Familiarity or experimentation period || 13 years || 6 mo. || 6 mo. |- | Number of samples made || 100 || >200 || >50 |} Notch filters or conformal reflectors where made in each of these materials and also in some of Dupont photopolymers. The dupont products have typically smaller bandwidths and lower maximum available index modulation, but the sensitivity is now in the 10 to 20 mj/cm*cm range and the sensitometric curves are similar to the DMP 128 curves in shape. The migrating photopolymers can not be over exposed in the reflection configuration and are fixed by white light or UV flood exposure or over exposure to laser light. == DCG #1 BB == [[File:pg29-1-l.gif|center|DCG1 BB]] {| border=1 |- | n = 1.560 || nl = 0.180 || d = 9.00um || lambda center = 550.nm |- | colspan=4 | Scan from 325.000 nm to 775.000 nm |- | colspan=2 | Minimum %T = 0.0365 || colspan=2 | Maximum %T = 99.9966 |- | colspan=2 | Multiple layer dielectric theory || 38.00% Damping || 9.00% Chirp |} [[File:pg29-1-r.gif|center|DCG1 BB]] {| border=1 |- | n = 1.560 || nl = 0.180 || d = 9.00um || 38.00 % Damping, 9.00 % Chirp |- | colspan=4 | Scan from 325.000 nm to 775.000 nm |- | colspan=2 | Maximum OD = 3.437 || colspan=2 | Minimum OD = 1.479E-05 |} == DCG #2 MB == [[File:pg29-2-l.gif|center|DCG2 MB]] {| border=1 |- | n = 1.560 || nl = 0.140 || d = 9.03um ||lambda center = 525.nm |- | colspan=4 | Scan from 300.000 nm to 750.000 nm |- | colspan=2 | Minimum %T = 0.0030 || colspan=2 |Maximum %T = 99.5860 |- | colspan=2 | Multiple layer dielectric theory || 36.00% Damping || 3.00% Chirp |} [[File:pg29-2-r.gif|center|DCG2 MB]] {| border=1 |- | n = 1.560 || nl = 0.140 || d = 9.03um || lambda center = 525.00nm |- | colspan=4 | Scan from 300.000 nm to 750.000 nm |- | colspan=2 | Maximum OD = 4.522 || colspan=2 | Minimum OD = 1.802E-03 |- | colspan=2 | Multiple layer dielectic theory || 36.00 % Damping || 3.00 % Chirp |} Reflectors in 10 microns of DCG can be processed to have all of the above characteristics. The time, temperature and alcohol concentrations all affect bandwidth and density. == Refractive index change as a function of depth for 901 points == [[File:pg30.gif|center]] Model of chirp in spacing and gradient in delta n Broadband effects in DCG, DMP 128 and other materials arise from processing induced chirps in the spacing of the fringe planes much like the variable spacing and amplitudes shown here. Absorption of light during exposure contributes to a broader bandwidth by introducing an exposure amplitude gradient in the index modulation through the depth of the film. The processing gradient caused by the diffusion of developers or solvents into the film may enhance or reduce the gradient depending on whether the film was exposed film side up or film side down (especially in a single beam configuration). This explains why two single beam reflection holograms can appear to be very different in color and bandwidth if one was shot film side up and the other film side down. This plot and the previous plots of amplitude and density and the following plots for DMP 128 were modelled using a program that takes into account a linear chirp in spacing and an exponential gradient in refractive index modulation resulting from absorption of the exposure light. A newer version will plot curves that have nonlinear chirps and generates shapes that more closely match those obtained in a scanning spectrophotometer. == Effects of gradient in n on polarizer performance == [[File:chirp.gif|center|Chirped DCG Reflector]] ''most S light reflected in high delta n region''<br> ''spectral bandwidth is approx. 150nm'' Another way to view the chirp in a plain mirror is shown above where the additional effect of a varying average n through the film is also seen. The fringes near the surface are seen to have wide spacings reflecting Red light with high efficiency because the delta n is highest there. As light travels deeper in finds shorter paths, higher n and lower delta n. The changing n makes a difference in the internal reflection angle, but not the external. This reflector acts as an efficient polarizer for green light because no P polarized light can be internally reflected. It is quite good at other colors as well. [[File:pg34.gif|center|Reconstruction wavelength in nm]] '''Dicromate as % of gelatin by weight''' The Color that DCG reconstructs at can be controlled by how much sensitizer and other dissolved solids are contained in the film before exposure. The sensitizer is washed out and the film loses from 5 to 30% of it's original thickness but processing causes 10 to 50% swelling, depending on how thick the film is and how hot the solvents are and on ph and an time and prehardening among other things. [[File:pg35.gif|center]] Color control can be done easily and repeatably in films of 8 to 20 microns by simply controlling the concentration of dichromate and keeping all processing steps conservative and constant. The graph above is a rough guide to reconstruction colors as a function of two popular exposure wavelengths and dichromate concentration. These numbers are typical of 8 to 10 micron films processed for 1 to 2 minutes in fixer followed by 30 seconds in each water and alcohol bath. The alcohol was about 49 deg C (120 degrees F), as usual processes vary with gelatin selection and condition. [[File:spindev.gif|center|Spin coating]] '''Spin coating at 70 to 100 RPM The thickness of a DCG film may be controlled with wire thickness and water concentration when using a meyer bar or may be controlled with rotation speed and water concentration on a simple turntable made from an old phonograph player. The graph above gives approximate thickness of a standard mixture of 10 grams of dichromate and 30 grams of gelatin in from 400 to 100 ml of water at 60 degrees C. 40 to 50 micron films are spun at 70 RPM, most others are at 100 RPM. Films over 20 microns thick stick to glass better if they are baked for at least 1 hour at 150 deg F and in water saturated air. [[File:spincoater.gif|center|Spin coater]] '''Spin coater''' [[File:dcgtime.gif|center|Process time in minutes]] Processing is either a cool single phase low modulation method or a warmer 2 phase higher modulation process. In between is an unstable region that will produce blotchy reflection holograms where the color difference between blotches is on the order of 50 nm or so. The unstable region is also defined by alcohol/water concentration and again depends on the source and condition of the gelatin. It is sufficient to know that it exists and that it may be avoided by changing temperatures or specific gravities up or down. Film thickness also strongly affects the choice of processing. Thin films are best done in such a way as to maximize the delta n and this is done with hot baths and short process times. Thick films require low delta n to take advantage of the angular and spectral selectivity available in thick films and are best processed at or near room temp for long times in each bath. The plot above is a guide to a starting point, the dots are regions we have worked in. ''Last modified on 6/3/99'' [[Category:Rallison]] aad63414d866e176342ee0fbf30c86f5902bb1d2 2115 2114 2013-05-27T23:53:54Z Jsfisher 1 wikitext text/x-wiki == Overall Comparison == [[File:deltan.gif|center|Exposure vs. density]] {| border=1 |- | Material || DCG || DMP128 || PVK |- | Sensitivity (mj/cm²) || 2-100 @ 442-532 || 30 @ 633-694 || 20 @ 488-532 |- | Approximate available index mod (Delta n) || 0.25 || 0.20 || 0.20 |- | Max O.D. attained in notch filters || 5 || 4 || 2.5 |- | Useful thickness range (microns) || 5-25 || 7-15 || 5-10 |- | Available Spectral Bandwidths (nm) || 10-150 || 10-100 || 20-100 |- | Playback compared to record wavelength || red shift for broad and/or blue shift for narrow | variable blue shift || red broad/blue narrow |- | Minimum recommended protection || 40 mil glass and epoxy || 4 mil Aclar || 4 mil mylar |- | Resistance to water || poor || fair || excellent |- | Familiarity or experimentation period || 13 years || 6 mo. || 6 mo. |- | Number of samples made || 100 || >200 || >50 |} Notch filters or conformal reflectors where made in each of these materials and also in some of Dupont photopolymers. The dupont products have typically smaller bandwidths and lower maximum available index modulation, but the sensitivity is now in the 10 to 20 mj/cm*cm range and the sensitometric curves are similar to the DMP 128 curves in shape. The migrating photopolymers can not be over exposed in the reflection configuration and are fixed by white light or UV flood exposure or over exposure to laser light. == DCG #1 BB == [[File:pg29-1-l.gif|center|DCG1 BB]] {| border=1 |- | n = 1.560 || nl = 0.180 || d = 9.00um || lambda center = 550.nm |- | colspan=4 | Scan from 325.000 nm to 775.000 nm |- | colspan=2 | Minimum %T = 0.0365 || colspan=2 | Maximum %T = 99.9966 |- | colspan=2 | Multiple layer dielectric theory || 38.00% Damping || 9.00% Chirp |} [[File:pg29-1-r.gif|center|DCG1 BB]] {| border=1 |- | n = 1.560 || nl = 0.180 || d = 9.00um || 38.00 % Damping, 9.00 % Chirp |- | colspan=4 | Scan from 325.000 nm to 775.000 nm |- | colspan=2 | Maximum OD = 3.437 || colspan=2 | Minimum OD = 1.479E-05 |} == DCG #2 MB == [[File:pg29-2-l.gif|center|DCG2 MB]] {| border=1 |- | n = 1.560 || nl = 0.140 || d = 9.03um ||lambda center = 525.nm |- | colspan=4 | Scan from 300.000 nm to 750.000 nm |- | colspan=2 | Minimum %T = 0.0030 || colspan=2 |Maximum %T = 99.5860 |- | colspan=2 | Multiple layer dielectric theory || 36.00% Damping || 3.00% Chirp |} [[File:pg29-2-r.gif|center|DCG2 MB]] {| border=1 |- | n = 1.560 || nl = 0.140 || d = 9.03um || lambda center = 525.00nm |- | colspan=4 | Scan from 300.000 nm to 750.000 nm |- | colspan=2 | Maximum OD = 4.522 || colspan=2 | Minimum OD = 1.802E-03 |- | colspan=2 | Multiple layer dielectic theory || 36.00 % Damping || 3.00 % Chirp |} Reflectors in 10 microns of DCG can be processed to have all of the above characteristics. The time, temperature and alcohol concentrations all affect bandwidth and density. == Refractive index change as a function of depth for 901 points == [[File:pg30.gif|center]] Model of chirp in spacing and gradient in delta n Broadband effects in DCG, DMP 128 and other materials arise from processing induced chirps in the spacing of the fringe planes much like the variable spacing and amplitudes shown here. Absorption of light during exposure contributes to a broader bandwidth by introducing an exposure amplitude gradient in the index modulation through the depth of the film. The processing gradient caused by the diffusion of developers or solvents into the film may enhance or reduce the gradient depending on whether the film was exposed film side up or film side down (especially in a single beam configuration). This explains why two single beam reflection holograms can appear to be very different in color and bandwidth if one was shot film side up and the other film side down. This plot and the previous plots of amplitude and density and the following plots for DMP 128 were modelled using a program that takes into account a linear chirp in spacing and an exponential gradient in refractive index modulation resulting from absorption of the exposure light. A newer version will plot curves that have nonlinear chirps and generates shapes that more closely match those obtained in a scanning spectrophotometer. == Effects of gradient in n on polarizer performance == [[File:chirp.gif|center|Chirped DCG Reflector]] ''most S light reflected in high delta n region''<br> ''spectral bandwidth is approx. 150nm'' Another way to view the chirp in a plain mirror is shown above where the additional effect of a varying average n through the film is also seen. The fringes near the surface are seen to have wide spacings reflecting Red light with high efficiency because the delta n is highest there. As light travels deeper in finds shorter paths, higher n and lower delta n. The changing n makes a difference in the internal reflection angle, but not the external. This reflector acts as an efficient polarizer for green light because no P polarized light can be internally reflected. It is quite good at other colors as well. [[File:pg34.gif|center|Reconstruction wavelength in nm]] '''Dicromate as % of gelatin by weight''' The Color that DCG reconstructs at can be controlled by how much sensitizer and other dissolved solids are contained in the film before exposure. The sensitizer is washed out and the film loses from 5 to 30% of it's original thickness but processing causes 10 to 50% swelling, depending on how thick the film is and how hot the solvents are and on ph and an time and prehardening among other things. [[File:pg35.gif|center]] Color control can be done easily and repeatably in films of 8 to 20 microns by simply controlling the concentration of dichromate and keeping all processing steps conservative and constant. The graph above is a rough guide to reconstruction colors as a function of two popular exposure wavelengths and dichromate concentration. These numbers are typical of 8 to 10 micron films processed for 1 to 2 minutes in fixer followed by 30 seconds in each water and alcohol bath. The alcohol was about 49 deg C (120 degrees F), as usual processes vary with gelatin selection and condition. [[File:spindev.gif|center|Spin coating]] '''Spin coating at 70 to 100 RPM The thickness of a DCG film may be controlled with wire thickness and water concentration when using a meyer bar or may be controlled with rotation speed and water concentration on a simple turntable made from an old phonograph player. The graph above gives approximate thickness of a standard mixture of 10 grams of dichromate and 30 grams of gelatin in from 400 to 100 ml of water at 60 degrees C. 40 to 50 micron films are spun at 70 RPM, most others are at 100 RPM. Films over 20 microns thick stick to glass better if they are baked for at least 1 hour at 150 deg F and in water saturated air. [[File:spincoater.gif|center|Spin coater]] '''Spin coater''' [[File:dcgtime.gif|center|Process time in minutes]] Processing is either a cool single phase low modulation method or a warmer 2 phase higher modulation process. In between is an unstable region that will produce blotchy reflection holograms where the color difference between blotches is on the order of 50 nm or so. The unstable region is also defined by alcohol/water concentration and again depends on the source and condition of the gelatin. It is sufficient to know that it exists and that it may be avoided by changing temperatures or specific gravities up or down. Film thickness also strongly affects the choice of processing. Thin films are best done in such a way as to maximize the delta n and this is done with hot baths and short process times. Thick films require low delta n to take advantage of the angular and spectral selectivity available in thick films and are best processed at or near room temp for long times in each bath. The plot above is a guide to a starting point, the dots are regions we have worked in. ''Last modified on 6/3/99'' [[Category:Rallison]] 48ab6cbb44f73bd2e935f915cc2a926af1ab5ef4 0 205 2116 1631 2013-05-28T00:15:47Z Jsfisher 1 wikitext text/x-wiki For an overview see [[Dichromated Gelatin#The Mechanics of Gelatin and the DCG Process | The Mechanics of Gelatin and the DCG Process]]. ===Dark Reaction=== '''Can you elaborate on dark reaction?''' '''Jeff Blyth responds:''' A good question ! ----- It needs a chemist to do it justice because it is complicated. Although it straightforwardly means dichromate reacts slowly with gelatin at room temperatures without light being involved, it does need some explaining. If you are not interested in the finer chemistry detail then stop reading here . Most oxidizing agents such as oxygen in the air, nitrates (saltpeter as in gunpowder etc) , and chlorates can be mixed with combustible materials and just sit there inactive virtually forever unless something such as a lighted match gives them that vital spark which triggers the chain reaction and rapid burn up. So these oxidants need what’s called “activation energy” as a kick start. However in the case of dichromates the chromium is a member of what are known in the Periodic Table as “transition metals” . These are inclined to have the peculiar ability to indulge in low activity with little activation energy which is why they are used universally as catalysts for low temperature reactions. They have variable valency which is why we have referred in this forum to CrVI going to Cr V going to CrIII The transition metal iron in our blood is doing this sort of low temperature oxidation work for us of course too. The transition metal effect is to do with atomic orbitals where the electrons have a large array of complicated empty orbitals to whizz about in some of the time and to get through barriers without having to be kicked to jump over the normal activation energy barrier that non- transition metal ions have to do. A non- transition metal such as say Aluminum which is always Al III in our water based alum chemistry here and cannot be reduced or oxidized to a different valency but it does make complexes with the gelatin and hardens it (but not quite as strongly as CrIII). So back to dichromate which has 6 electrons missing from its uncombined metallic state. The electrons have been taken mainly by 3 oxygen atoms in a not very strong arrangement and these electrons are actively whizzing around the Cr atom’s empty orbitals as well as their main base around the oxygen atoms. Energy is gained for the system if 3 of them can return permanently to the Cr atom by being instrumental in getting the oxygens to swap them for other electrons in neighboring organic groups in the gelatin to give more stable arrangements producing partially oxidized gelatin. So the dark reaction of dichromate is primarily a matter of oxidation of the gelatin without a kick start with light energy or extra heat and it can be slowed down in a ‘fridge but needs to be in a freezer to really slow it down. Incidentally the less pure the dichromate the more it contains other transition metals such as copper and the more it enables this catalysed oxidizing effect to occur in the dark. More acidity also increases it which is why the more acidic ammonium salt in unexposed gelatin film gives it a shorter shelf life than the potassium salt. ===Gelatin and Anti-Crystallization Properties=== Let’s remember that yet one more of the great features of gelatin is its ability to hold quite concentrated solutions of salts within itself as a form of gelled solid solution. This is a great feature for us holographers because without it some of our valuable techniques would be spoiled by the normal crystallization processes which would transform glass clear film into the equivalent of frosted window glass. This special anti-crystallization feature can be undermined if we allow concentrated salt solutions to crystallize on the surface of the gelatin because it can then encourage crystal seeding to occur within the gelatin. So if one is making a “G307” system where the coated gelatin is dipped into a bath of say 6% potassium dichromate one needs to gently wipe off the excess droplets of dichromate salt off the surface before drying . (This system needs high dichromate salt concentrations for exposure to 532nm but NOT if one is exposing with blue wavelengths.) This also applies to the diffusion system for making silver halide gelatin film, where careful removal of silver nitrate solution in surface droplets is needed before drying and immersing in the bromide bath. Another (but less common ) way that anti -crystallization property can me reduced is by excessive drying by overheating so that the inherently bound in water found in normal gelatin film is driven off or the salt-laden gelatin is stored under very low humidity. Jeff ===Converting Dichromate to Chromate=== I hope I can just clarify something about potassium dichromate versus chromate. You can readily convert dichromates into chromates by adding the right amount of alkali to a stirred solution of say 5% potassium dichromate until it gets to a pH of about 8 to 9. The chemistry really is straightforward enough. I will just run through it for future reference. Potassium chromate is the potassium salt of Chromic Acid : H2CrO4 where the 2 acid H's are substituted for 2 K's Now to see how potassium Dichromate (K2Cr2O7) is made up, please just note down the total formula from adding one potassium chromate (K2CrO4) to one chromic acid (H2CrO4). You then get a total of K2H2Cr2O8 . now just take away 1 H2O and you get K2Cr2O7. So dichromates are all just 1:1 combinations of chromate salts with chromic acid. There is of course no need to use potassium hydroxide to do the conversion, Na OH will work just fine. I have just calculated that 100 ml of 5% K2Cr2O7 will require 1.36 g solid sodium hydroxide to convert it all to the chromate form. (The colour of the solution changes from the intense orange yellow to a light canary yellow when the conversion is complete.) Some of you will have already spotted that 5% K2Cr2O7 solution has got more chromium compound in it than the intended 5% K2 Cr O4 solution. To make it equivalent you need to cut down the volume of solution used by a third. But I don’t think this is a critical issue . Jeff ac6437f83ebb49ddbdafd6b1b1f5f20d05f31e24 2117 2116 2013-05-28T00:17:43Z Jsfisher 1 wikitext text/x-wiki For an overview see [[Dichromated Gelatin#The Mechanics of Gelatin in the Dichromated Holography Process| The Mechanics of Gelatin and the DCG Process]]. ===Dark Reaction=== '''Can you elaborate on dark reaction?''' '''Jeff Blyth responds:''' A good question ! ----- It needs a chemist to do it justice because it is complicated. Although it straightforwardly means dichromate reacts slowly with gelatin at room temperatures without light being involved, it does need some explaining. If you are not interested in the finer chemistry detail then stop reading here . Most oxidizing agents such as oxygen in the air, nitrates (saltpeter as in gunpowder etc) , and chlorates can be mixed with combustible materials and just sit there inactive virtually forever unless something such as a lighted match gives them that vital spark which triggers the chain reaction and rapid burn up. So these oxidants need what’s called “activation energy” as a kick start. However in the case of dichromates the chromium is a member of what are known in the Periodic Table as “transition metals” . These are inclined to have the peculiar ability to indulge in low activity with little activation energy which is why they are used universally as catalysts for low temperature reactions. They have variable valency which is why we have referred in this forum to CrVI going to Cr V going to CrIII The transition metal iron in our blood is doing this sort of low temperature oxidation work for us of course too. The transition metal effect is to do with atomic orbitals where the electrons have a large array of complicated empty orbitals to whizz about in some of the time and to get through barriers without having to be kicked to jump over the normal activation energy barrier that non- transition metal ions have to do. A non- transition metal such as say Aluminum which is always Al III in our water based alum chemistry here and cannot be reduced or oxidized to a different valency but it does make complexes with the gelatin and hardens it (but not quite as strongly as CrIII). So back to dichromate which has 6 electrons missing from its uncombined metallic state. The electrons have been taken mainly by 3 oxygen atoms in a not very strong arrangement and these electrons are actively whizzing around the Cr atom’s empty orbitals as well as their main base around the oxygen atoms. Energy is gained for the system if 3 of them can return permanently to the Cr atom by being instrumental in getting the oxygens to swap them for other electrons in neighboring organic groups in the gelatin to give more stable arrangements producing partially oxidized gelatin. So the dark reaction of dichromate is primarily a matter of oxidation of the gelatin without a kick start with light energy or extra heat and it can be slowed down in a ‘fridge but needs to be in a freezer to really slow it down. Incidentally the less pure the dichromate the more it contains other transition metals such as copper and the more it enables this catalysed oxidizing effect to occur in the dark. More acidity also increases it which is why the more acidic ammonium salt in unexposed gelatin film gives it a shorter shelf life than the potassium salt. ===Gelatin and Anti-Crystallization Properties=== Let’s remember that yet one more of the great features of gelatin is its ability to hold quite concentrated solutions of salts within itself as a form of gelled solid solution. This is a great feature for us holographers because without it some of our valuable techniques would be spoiled by the normal crystallization processes which would transform glass clear film into the equivalent of frosted window glass. This special anti-crystallization feature can be undermined if we allow concentrated salt solutions to crystallize on the surface of the gelatin because it can then encourage crystal seeding to occur within the gelatin. So if one is making a “G307” system where the coated gelatin is dipped into a bath of say 6% potassium dichromate one needs to gently wipe off the excess droplets of dichromate salt off the surface before drying . (This system needs high dichromate salt concentrations for exposure to 532nm but NOT if one is exposing with blue wavelengths.) This also applies to the diffusion system for making silver halide gelatin film, where careful removal of silver nitrate solution in surface droplets is needed before drying and immersing in the bromide bath. Another (but less common ) way that anti -crystallization property can me reduced is by excessive drying by overheating so that the inherently bound in water found in normal gelatin film is driven off or the salt-laden gelatin is stored under very low humidity. Jeff ===Converting Dichromate to Chromate=== I hope I can just clarify something about potassium dichromate versus chromate. You can readily convert dichromates into chromates by adding the right amount of alkali to a stirred solution of say 5% potassium dichromate until it gets to a pH of about 8 to 9. The chemistry really is straightforward enough. I will just run through it for future reference. Potassium chromate is the potassium salt of Chromic Acid : H2CrO4 where the 2 acid H's are substituted for 2 K's Now to see how potassium Dichromate (K2Cr2O7) is made up, please just note down the total formula from adding one potassium chromate (K2CrO4) to one chromic acid (H2CrO4). You then get a total of K2H2Cr2O8 . now just take away 1 H2O and you get K2Cr2O7. So dichromates are all just 1:1 combinations of chromate salts with chromic acid. There is of course no need to use potassium hydroxide to do the conversion, Na OH will work just fine. I have just calculated that 100 ml of 5% K2Cr2O7 will require 1.36 g solid sodium hydroxide to convert it all to the chromate form. (The colour of the solution changes from the intense orange yellow to a light canary yellow when the conversion is complete.) Some of you will have already spotted that 5% K2Cr2O7 solution has got more chromium compound in it than the intended 5% K2 Cr O4 solution. To make it equivalent you need to cut down the volume of solution used by a third. But I don’t think this is a critical issue . Jeff 9da963474fc1b90cf981789f3fe1b803487ffbc5 0 212 2118 1647 2013-05-28T00:20:36Z Jsfisher 1 wikitext text/x-wiki Dichromated Gelatin (DCG) is one of the brightest media for recording holograms. It is used in art as well as [[HOE]] fabrication. [[A Beginners Approach to DCG]] by John Pecora [[A Simple DCG Recipe]] [[G307 DCG Formula]] Increased overall sensitivity and to 514nm - 532nm [[MBDCG]] [[DCG Theory]] [[Sealing DCG Holograms]] [[Dichromated Gelatin#The Mechanics of Gelatin in the Dichromated Holography Process | The Mechanics of Gelatin in the Dichromated Holography Process]] [[DCG Variables]] [[Coating Methods]] [[Troubleshooting DCG]] 9834bf5855d20dc65fbbf736b2fd7e37a56b7087 0 243 2119 334 2013-05-28T00:21:46Z Jsfisher 1 /* Questions and Answers */ wikitext text/x-wiki ==G307== (initial entry by John Pecora) This is Jeff Blyth’s formula for plates that exhibit an increased sensitivity to the green wavelengths 514 and 532. I have been exposing between 5 to 20mJ/cm^2 with very bright results. First it is necessary to coat plates with an emulsion of just gelatin and water using your preferred method (veil, bar, spin etc.) followed by curing of at least 12 hours. After curing the plates can be stored indefinitely, preferably in the refrigerator and just a few can be sensitized only when needed. ==Pre-exposure== To sensitize the plates, make up a solution as follows; Weigh out in order:- *0.5g glycerine *0.3g Aluminum Sulfate or Alum *100 ml distilled or de-ionized water *dissolve everything up then add: *5g potassium dichromate. Chill the solution to 5 degree C and then pour the solution into a container just larger then your glass plate. At this point a red safelight needs to be used and the standard yellow bug light for DCG will not work. Tilt the container to the side slightly, now take the glass and place it in the container, putting the edge in the deeper end of the liquid first and laying it down all in one motion while leveling the container. You will see the liquid slide across the top of the plate evenly. Only leave your plate in the solution for about half a minute then shake the plate free of droplets and wipe over the glass back with a paper towel. Stand the plates up against a wall at an angle and gently blow with a small desk fan or a hair dryer that has a cool setting until they are touch dry. At this point the alum in the formulation starts doing its job and is hardening up the coating a bit but it is only a gradual step and it is not instant. Now your plates should be used as you normally use them, needing to be shot at once or refrigerated for later use. AMENDMENT: '''Storage note about this solution''' If possible always try to use freshly made solution. However it can be stored in the dark in a fridge for a few days. The glycerine content will degrade rapidly if left in a bright light and slowly degrade in a dark reaction in the fridge. It may be possible to rejuvenate it with more glycerine but it is unlikely to be as good as the fresh stuff. ==Post exposure treatment== You need to have your oven at 100C (212F) and have a flat clean metal plate in it so that the metal instantly and evenly heats up your dry exposed plate. I have found that for a 4x5 plate 2 minutes is a good starting point. Depending on hardness of gelatin and exposure energy you may need to adjust this time. If the plates come out milky, increase the time. For the brightest hologram keep the baking time as low as possible without the plate coming out milky. After baking at 100C take the plate out and put it immediately onto a cold metal surface to rapidly and evenly cool the plate. Once the plate has cooled to room temperature, process with water and alcohol just as the standard DCG would be processed but use DI water in a container as the KDi will be lost into this water. When you are finished Sodium Metabisulfite can be added to change the CrVI to CrIII which is more environmentally friendly. You may need to leave the plate in the water rinse a bit longer to get all of the potassium dichromate out depending on the thickness of your emulsion. I use two baths, one for the majority of soaking to get most of the KDi out and the second as a quick final rinse. Once you have CrIII it will then be able to be precipitated out in a saturated solution of your sodium carbonate. An alternate drying method would be to just hit the plate with the hair dryer or other blower for just a few seconds to get the majority of alcohol off but then put the plate back into the oven at 100C until completely dry. ==Questions and Answers== ''' Q. What qualifies as "curing" for newly coated plates? 12 hours at any particular temp or humidity ? Well, the key is to have the gelatin cured enough to remain on the plate and not dissolve in the sensitizing bath. I would coat and leave in positive flow bench for 4 - 8 hours. At this point I would put the plain gelatin the fridge for later sensitizing and use. 12 hours is the minimum and as it is plain gelatin, storing for days or weeks is no problem. I believe 12 hours would be adequate for most environmental conditions. ''' Q. At what point does the sensitizer become light sensitive? Should the mixing be carried out under a safelight? Yes. Anytime you add KDi or AmDi to glycerine or gelatin you should use a safelight. ''' Q. What happens if one leaves the plate in solution more than 30 seconds? The only negative I can see is the gelatin will start to dissolve. ''' Q. Any chemists out there have any suggestions for a "preservative" to limit the glycerin dark reaction? Why do we want to limit it? It is the dark reaction additive that gives the G307 its increased sensitivity. ''' Q. Why is a cold plate used after post-exposure baking? This is used for larger (4x5" and up) plates so that the emulsion cools uniformly. Without this you may find that the brightness varies from the center to the outer edge of the plate due to differential cooling. Also, to cool the plate immediately such that the baking time can be more precisely controlled. The post baking is the additional hardening. If the plate was allowed to cool to room temp without a cold plate, obviously the hardening from the baking would be extended. Vary the room temperature and the control time is lost. ''' Q. What does this mean? "Once the plate has cooled to room temperature, process with water and alcohol just as the standard DCG would be processed but use DI water in a container as the KDi will be lost into this water." Soak the plate first to dissolve out the KDi? Yes, after the baking hardening there is still some unused KDi that will dissolve out. It is best to dissolve this out in a container such that it can be neutralized before disposing. ''' Q. "An alternate drying method. . ." Alternate to what? Alternate to the standard DCG method of drying which is with forced hot air after the last alcohol bath. ''' Q. What processing regime have people had good success with? Combinations of alcohol %, fixer, etc. DCG processing can be on [[A Beginners Approach to DCG]], [[MBDCG]] and [[Dichromated Gelatin#The Mechanics of Gelatin in the Dichromated Holography Process | The Mechanics of Gelatin in the Dichromated Holography Process]]. It's unclear if or how the process might be changed for for G307. There is no fixer used in the G307. The G307 is different only up to the water rinse bath just prior to the alcohol dryings. All papers and techniques to change bandwidth or color from the water bath on, for standard processing, should apply. ''' Q. When using Sodium Metabisulfite to make the CrVI more environmentally friendly, how much should be used? How can one tell when one has added enough to change the CrVI to CrIII? CrVI is orangish in color. CRIII is bluish. When the solution has turned blue, that should be enough. A little more is better then not enough. I always add till blue and then some extra. Sodium Metabisilite is inexpensive. Unless you know exactly how much KDi is in the solution, I am not sure an exact measurement of Sodium Metabisulfite can be found. I wonder if there is a test to check if there is any CrVI left in the solution...??? a566c79b33a9a554d6a1278d8a49fc37460b837d 6 897 2120 2013-05-28T00:42:40Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 233 2121 314 2013-05-28T00:48:48Z Jsfisher 1 wikitext text/x-wiki A Farady rotator is made from a non-linear material with an electric current passing either across the light path or along the light path in the crystal. They are used in [[Ring Laser|Ring Lasers]] and in [[Faraday Isolator|Faraday Isolators]]. A Faraday Rotator rotates light using the Faraday Effect. The degree of rotation is controled by an induced magnetic field. The two main uses for a Faraday Rotator are putting a polarizer in front so that back scatter is rotated and blocked by the polarizer and using them with wave plates to make a ring laser. [[Image:Faraday-effect.svg]] <!-- [[Image:FaradayRotator.png]] --> The plane of linearly polarized light is rotated when a magnetic field is applied parallel to the propagation direction. The empirical angle of rotation is given by: :<math> \beta = VBd \!</math> Where * <math>\beta</math> is the angle of rotation (in radians), * <math>B</math> is the magnetic flux density in the direction of propagation (in teslas), * <math>d</math> is the length of the path (in meters) where the light and magnetic field interact, and * <math>V</math> is the Verdet constant for the material. This empirical proportionality constant (in units of radians per tesla per meter, rad/(T·m)) varies with wavelength and temperature and is tabulated for various materials. 20423bd851fb796bb5c07938d38d497c2cf39360 2122 2121 2013-05-28T00:55:46Z Jsfisher 1 wikitext text/x-wiki [[Image:Faraday-effect.svg| right]] A Faraday rotator is an optical device that rotates the polarization of light due to the Faraday effect, which in turn is based on a magneto-optic effect. The Faraday rotator works because one polarization of the input light is in ferromagnetic resonance with the material which causes its phase velocity to be higher than the other. They are used in [[Ring Laser|Ring Lasers]] and in [[Faraday Isolator|Faraday Isolators]]. A Faraday Rotator rotates light using the Faraday Effect. The degree of rotation is controled by an induced magnetic field. The two main uses for a Faraday Rotator are putting a polarizer in front so that back scatter is rotated and blocked by the polarizer and using them with wave plates to make a ring laser. <!-- [[Image:FaradayRotator.png]] --> The plane of linearly polarized light is rotated when a magnetic field is applied parallel to the propagation direction. The empirical angle of rotation is given by: :<math> \beta = VBd \!</math> Where * <math>\beta</math> is the angle of rotation (in radians), * <math>B</math> is the magnetic flux density in the direction of propagation (in teslas), * <math>d</math> is the length of the path (in meters) where the light and magnetic field interact, and * <math>V</math> is the Verdet constant for the material. This empirical proportionality constant (in units of radians per tesla per meter, rad/(T·m)) varies with wavelength and temperature and is tabulated for various materials. 2c4df286a8ec5d456278e4b1f1d26963e18038c7 0 588 2123 2086 2013-05-28T02:24:30Z Jsfisher 1 wikitext text/x-wiki Veil Coating ==Veil Coating - Part I== The glass can be coated at room temperature or warmed up to the temperature of the emulsion (110 - 120°F.). The warmer the glass is, the thinner the final emulsion thickness will be. A great starting point is room temperature glass (70°F.) Take a cleaned glass plate and blow it off with a shot of canned air to remove any dust particles. Hold the glass with one hand at a 45° angle over a heated excess tray. Use gloves. You can use a therapeutic heating pad to keep your tray warm. This keeps the emulsion from hardening in the excess tray. Slowly pour the emulsion up the left side of the plate about ¼ inch from the edge, then across the top and down the right hand side. If this is done correctly you will notice a nice even flow across the plate when you are pouring across the top. Then take a ¼ sheet of paper towel and ball it up and wipe about a ¼ inch of emulsion from the bottom edge of the plate in one continuous motion. ===Post Spinning - Part IIa=== Take the plate and immediately place it on a turn table and spin it as 78 RPM. An old phonograph works great and has been used for years by many holographers. Let this spin for 10 minutes. A helpful suggestion is to make a rack that can hold plates horizontally on the spinner but leave a nice air space between the plates so they can dry evenly. Then one can coat and spin many plates at a time only stopping the spinner momentarily to quickly load the next freshly coated plate. I have found that spinning longer is better and I allow my plates to spin for at least 10 minutes after the last plate has been loaded into the spinner. ===Post Leaning/Lying - Part IIb=== If a spinner is not available then lean the plate against a wall in a tray that can be use to catch the excess for thinner emulsions or lay the plate flat and horizontally for a thicker coating. ===Re-Using Emulsion - Part III=== If you run out of emulsion in the pouring container while coating, just pour the warmed excess back into the pouring container keeping the pouring container at an angle so as not to cause any bubbles. Allow the emulsion to come back up to coating temperature of 110 to 120°F. After the plates are coated the excess emulsion can be poured back into the container and stored in the refrigerator for a later coating session. I have found the emulsion will keep for weeks this way. Although refilter does not have to be done during one session if things are kept clean, I suggest refiltering after refrigerating and re-cooking. ==Dave Battin's Article on Veil Coating== Having tried all the methods available to most hobby holographers, I've found the best method for me is the veil coat method. I have attached a still shot to give you a preview to this method, and I plan on showing a step by step instructions so all should be able to coat easily. please see the video clip at the bottom of this page to see this method in action, sorry for the weird color ,as im actually making DCG film under a yellow/red safelite [[Image:VeilFig1.jpg]] The size of the glass is 4"x16" if i trim off one inch the top it will yield me Three nice 4x5s. When acquiring glass I have found a great source is at your local art store, the type that has a special every week, (here its called Michael's), Its the replacement glass sold for picture frames, located in or near the framing department. It comes cleaned sealed and slightly lighter/weight than the regular 1/8" glass found at the local hardware store. The largest I can get is 16"x20" for @ $5 each, not bad for coming cleaned and ready to cut .................. subbing will be next [[Image:VeilFig2.jpg]] I have found it much easier to cut the glass into 4”x16” pieces before subbing. [[Image:VeilFig3.jpg]] A simple jig to cut your glass will give you nice consistent cuts every time. By banking your glass to the stop and placing the proper width spacer on top, simply bank your glass cutter against the spacer and slice. It’s best to provide a little lubricant to help the cut a little (I lick the cutter first). Now that my glass is cut, I'll prep the surface for coating. This glass is pretty clean already. If you’re unsure, I would soak it in a 20% Clorox Solution (soak over night), and after a quick water wash, soak in the Cascade (dishwasher soap) and water mix (I use a small handful for 2 gallons of water or so) again soak overnight after a slight scrubbing action using a plastic scrubby pad. [[Image:VeilFig4.jpg]] After removal of the glass from the Cascade, I give it a quick dip into clean water and then a final plunge into what they refer to as (Trisodium Phosphate) substitute. Where I live, they won’t allow the use of the real TSP, as it’s bad for the ground water. Allow to dry by leaning on wall, sitting on a paper towel. [[Image:VeilFig5.jpg]] The glass is now ready to be coated, but we must add a few extra items to make things easier later on ………………………… [[Image:VeilFig6.jpg]] Well, the glass is almost ready to coat. We will have to attach a few pieces of tape and paper to make this work correctly. [[Image:VeilFig7.jpg]] I do all the work under my laminar flow booth. It helps to place your plate (the glass will now be referred to as plate) on some type of pedestal (as shown) or block of wood. (photo A) Start by placing the plate face down on the pedestal and applying plain old ordinary scotch tape to both long sides of plate, adhere tape directly to the back of the plate, allowing only half of the tape to hang off the sides the entire length of the plate (photo B). I call these gutters. These will allow you to coat your plate up to the very edge without any waste. Once the gutters are in place, turn your plate face up, and again place on the pedestal. Now using a short piece of tape slightly longer than the width of your plate, attach it to the top, adhering directly onto the face of the plate, again leaving half the tape to hang off the top (photo C). Now that the top tape is adhered, we will now apply the “Tab”, a small 1x5 inch piece of paper applied from the back of the plate stuck to the tape along the top. This tab will be used numerous times throughout the operation so be sure its adhered well (photo D). Your plate should now look like this: [[Image:VeilFig8.jpg]] The paper tab I attached to the top of the plate, will now act as a handle and I can hold it while doing a final cleaning, I lay the glass across my leg and wipe it clean (front only)using a folded paper towel and simple Windex glass cleaner ,always spray on the towel and not the glass! With my method of coating I felt to lean is to be constant! The angle of incline is not so important, but its to always repeat the same angle, I achieve this by placing the plate in a holding jig, see the video to help explain, the film is now ready for coating . A few minuets after coating , the paper tab will now allow you to attach a large paper clip, and hang your film to dry. By using a lab base and thin rod clamped horizontally, its easy to hang 12 4x5s to dry! The blow dryer I use is old and weak! But it has two settings hi/low heat, at low it is very weak (blowing), and you will see me blowing close to the wet emulsion. Most new blow dryers will be way to powerful for this. To apply the emulsion I use a simple squirt bottle, very easy to regulate flow, with the current bottle, I can coat three 4x16 plate before I have to recharge the bottle. [[Media:coatmeth.wmv | Dave Battin's Coating Video]] [http://www.youtube.com/watch?v=b0Toqidt0eo Dave Battin's Coating Video on YouTube] 81f41ea3f106bfbf3a5399fb690aa2058a513c6a 0 203 2124 1623 2013-05-31T03:36:04Z Jsfisher 1 wikitext text/x-wiki ==Holography Glossary== [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- ; Daguerreotype : first practical and commercial photographic process, introduced by Louis Daguerre in 1839. The sensitive material comprised silver iodide, deposited on a polished silver plated copper base. A positive image was produced by camera exposure and mercury "development", which turned light struck halides gray-white. The image was made permanent by immersing the plate in a solution of sodium chloride. ; Daylight enlarger : early type of enlarger using light from a hole in a window to provide illumination of the negative. ; Desensitizing : reducing an exposed emulsion's sensitivity to light. This can be done by the application of dyes or by using oxidation agents ; Developer : chemical bath containing reducing agents, which converts exposed silver halide to black metallic silver, making the latent image visible. ; Development : process of converting exposed silver halide to a visible image. The term is also used in non-silver halide processes, for example, [[dichromated gelatin]] where image formation is a completely different mechanism, but the end result is similar. ; Diazo : abbreviation of diazonium compounds, which decompose under the action of intense blue or ultraviolet radiation, forming an image in an azo dye. ; Dichroic filters : produced by metallic surface coatings on glass to form colors by interference of light. Used in high quality color enlarger heads. ; Dichroic fog : purple-green bloom usually seen on negatives and caused by the formation of silver in the presence of an acid. ; Diffraction Efficiency : a measure of performance for a diffraction grating or hologram. Diffraction efficiency is the ratio of optical power diffracted by the grating to the power incident. More simply, it is the percentage of light diffracted. In holography, higher diffraction efficiencies are preferred, yielding brighter holograms. ; Dilution : reduction in the strength of a liquid by mixing it with an appropriate quantity of water. ; Dimensional stability : substance's ability to remain unchanging in size when subjected to processing and drying. ; Dish development : method of development used for processing single sheet, cut film or paper by immersing in a shallow dish of developer and agitating by rocking the dish. ; Documentary photography : taking of photographs to provide a record of social and political situations with the aim of conveying information. ; Dodging : control of exposure in photographic printing achieved by reducing exposure to specific areas of the paper. Typically, a small disk mounted on the end of a thin wire would be wiggled over an area to be lightened during enlargement. (Many photographers simply used their fingers as the "dodge.") Less light meant a lighter area and the wiggling helped blend the lightened area smoothly with the area around it. ; Dry down : refers to the amount a print darkens after drying. ; Dry mounting : method of attaching prints to mounting surfaces by heating shellac tissue between the mount and the print. ; Dye destruction process : method of producing a colored image by partially bleaching fully formed dye layers incorporated in the sensitive material. ; Dye-image monochrome films : black & white negative films designed for color processing. ; Dye sensitizing : defined as all silver halides used in black & white emulsions are sensitive to blue light. Early photographic materials possessed only this sensitivity. ; Dye transfer print : method of producing color prints via three color separation negatives. Negatives are used to make positive matrices, which are dyed in subtractive primaries and printed in register. ; Dynamism : picture structuring which relates to a sense of movement and action. 4d1db031e916028a46bd32e017138057e4505f5e 2125 2124 2013-05-31T03:37:40Z Jsfisher 1 /* Holography Glossary */ wikitext text/x-wiki ==Holography Glossary== [[A]],[[B]],[[C]],[[D]],[[E]],[[F]],[[G]],[[H]],[[I]],[[J]],[[K]],[[L]],[[M]],[[N]],[[O]],[[P]],[[Q]],[[R]],[[S]],[[T]],[[U]],[[V]],[[W]],[[X]],[[Y]],[[Z]] ---- ; Daguerreotype : first practical and commercial photographic process, introduced by Louis Daguerre in 1839. The sensitive material comprised silver iodide, deposited on a polished silver plated copper base. A positive image was produced by camera exposure and mercury "development", which turned light struck halides gray-white. The image was made permanent by immersing the plate in a solution of sodium chloride. ; Daylight enlarger : early type of enlarger using light from a hole in a window to provide illumination of the negative. ; Desensitizing : reducing an exposed emulsion's sensitivity to light. This can be done by the application of dyes or by using oxidation agents ; Developer : chemical bath containing reducing agents, which converts exposed silver halide to black metallic silver, making the latent image visible. ; Development : process of converting exposed silver halide to a visible image. The term is also used in non-silver halide processes, for example, [[Dichromated Gelatin|dichromated gelatin]] where image formation is a completely different mechanism, but the end result is similar. ; Diazo : abbreviation of diazonium compounds, which decompose under the action of intense blue or ultraviolet radiation, forming an image in an azo dye. ; Dichroic filters : produced by metallic surface coatings on glass to form colors by interference of light. Used in high quality color enlarger heads. ; Dichroic fog : purple-green bloom usually seen on negatives and caused by the formation of silver in the presence of an acid. ; Diffraction Efficiency : a measure of performance for a diffraction grating or hologram. Diffraction efficiency is the ratio of optical power diffracted by the grating to the power incident. More simply, it is the percentage of light diffracted. In holography, higher diffraction efficiencies are preferred, yielding brighter holograms. ; Dilution : reduction in the strength of a liquid by mixing it with an appropriate quantity of water. ; Dimensional stability : substance's ability to remain unchanging in size when subjected to processing and drying. ; Dish development : method of development used for processing single sheet, cut film or paper by immersing in a shallow dish of developer and agitating by rocking the dish. ; Documentary photography : taking of photographs to provide a record of social and political situations with the aim of conveying information. ; Dodging : control of exposure in photographic printing achieved by reducing exposure to specific areas of the paper. Typically, a small disk mounted on the end of a thin wire would be wiggled over an area to be lightened during enlargement. (Many photographers simply used their fingers as the "dodge.") Less light meant a lighter area and the wiggling helped blend the lightened area smoothly with the area around it. ; Dry down : refers to the amount a print darkens after drying. ; Dry mounting : method of attaching prints to mounting surfaces by heating shellac tissue between the mount and the print. ; Dye destruction process : method of producing a colored image by partially bleaching fully formed dye layers incorporated in the sensitive material. ; Dye-image monochrome films : black & white negative films designed for color processing. ; Dye sensitizing : defined as all silver halides used in black & white emulsions are sensitive to blue light. Early photographic materials possessed only this sensitivity. ; Dye transfer print : method of producing color prints via three color separation negatives. Negatives are used to make positive matrices, which are dyed in subtractive primaries and printed in register. ; Dynamism : picture structuring which relates to a sense of movement and action. 2ec619d31b61d3555f0cedb2e342a5177e07d593 0 866 2126 1934 2013-06-12T11:18:21Z Jsfisher 1 wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in two Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 , http://holoforum.org/forum/viewtopic.php?f=7&t=497 , http://holoforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} 8c2efc3782a8c7d2764339e81f471a8f32848267 2130 2126 2013-06-22T20:19:46Z Jsfisher 1 /* Ferric Ammonium Oxalate */ wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in three Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 , http://holoforum.org/forum/viewtopic.php?f=7&t=497 , http://holoforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} 9fdb601c21809c9fb1ce1b8ad06bcb9d24918a37 6 898 2127 2013-06-12T20:37:57Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 899 2128 2013-06-12T20:38:20Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 900 2129 2013-06-16T15:18:53Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 489 2131 1995 2013-06-26T03:13:32Z Jsfisher 1 wikitext text/x-wiki http://abc.def.com/asdf Text <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} [[Sandbox / Subsandbox]] This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y} scriptscriptstyle</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> 5253f8d89baf92599f03a412fce1dbe3e42e712b 2133 2131 2013-06-26T03:19:56Z Jsfisher 1 wikitext text/x-wiki http://abc.def.com/asdf Text <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} [[Sandbox / Subsandbox]] This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== [[User:Jsfisher|/jsfisher]] ([[User talk:Jsfisher|talk]]) 23:19, 25 June 2013 (EDT) ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y} scriptscriptstyle</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> 8d81d8e8f95cc44c748e06a6164d0e3e6726a4ac 0 901 2132 2013-06-26T03:13:56Z Jsfisher 1 Created page with "Yet another text page." wikitext text/x-wiki Yet another text page. e7d87352bb4e6305a46b59e5179a99687eb735f0 1 541 2134 1233 2013-06-26T03:34:36Z Jsfisher 1 wikitext text/x-wiki Test: [[Talk:Sandbox/SubPage]] Test: [[Talk:Sandbox/Talk:Subpage]] I like the beginning you have. The blue writing for the links is a little difficult however. Nice Image. eba0be31f808da179db88dc62ee767db591dcf88 1 902 2135 2013-06-26T03:34:59Z Jsfisher 1 Created page with "Test sub test" wikitext text/x-wiki Test sub test 17301abc1462bb547dab921a7318c36629dd8004 1 903 2136 2013-06-26T03:35:24Z Jsfisher 1 Created page with "sdfghj" wikitext text/x-wiki sdfghj 39493509ff3fd47ee5fde2ca6ca0d1b25acf3a75 0 1 2137 2113 2013-08-03T01:54:35Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). <!-- * [[Archives|Archives]] --> 9f7535f5b3ec9eec7d98b58db585f2e8d9bb5194 6 905 2139 2013-08-03T15:12:53Z Dinesh 3 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 685 2140 1436 2013-08-03T15:13:19Z Dinesh 3 Dinesh uploaded a new version of &quot;[[File:Grains.pdf]]&quot; wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 875 2141 2103 2013-08-04T16:06:00Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:8_LAJPE_525_Ramon_Gomez_Preprint_corr_f.pdf | Low cot instrumentation for spin-coating deposition of thin films in an undergraduate laboratory]]''', Ramon Gómez Aguilar, Jaime Ortiz López. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * A few papers by Dinesh Padiyar. ** '''[[Media:grains.pdf | Silver Halide Materials]]''' (the "grains.pdf" document). ** '''[[Media:Colour.pdf | Colour]],''' relating to color sensitivity of human eye. ** '''[[Media: Aberrations_in_Holography.pdf ‎| Aberrations in Holography]],''' coauthor Joy Padiyar. * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. * '''[[Media:Kock-LasersHolography.pdf | Lasers and Holography]],''' William Kock. * '''[[Media:kaveh-PhD.pdf | Techniques in Display Holography]],''' Kaveh Bazargan, PhD thesis, University of London, April 1986. bb97f2f24816f9b46412ae48fccb1819558600b9 2145 2141 2013-08-18T05:07:28Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:8_LAJPE_525_Ramon_Gomez_Preprint_corr_f.pdf | Low cot instrumentation for spin-coating deposition of thin films in an undergraduate laboratory]]''', Ramon Gómez Aguilar, Jaime Ortiz López. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[[Media:60208346.pdf | An aqueous photopolymer for classroom holography]]''', J. Blyth. * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * A few papers by Dinesh Padiyar. ** '''[[Media:grains.pdf | Silver Halide Materials]]''' (the "grains.pdf" document). ** '''[[Media:Colour.pdf | Colour]],''' relating to color sensitivity of human eye. ** '''[[Media: Aberrations_in_Holography.pdf ‎| Aberrations in Holography]],''' coauthor Joy Padiyar. * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. * '''[[Media:Kock-LasersHolography.pdf | Lasers and Holography]],''' William Kock. * '''[[Media:kaveh-PhD.pdf | Techniques in Display Holography]],''' Kaveh Bazargan, PhD thesis, University of London, April 1986. 2ac09d0df0b523717f32c6f1fee73ff1a8b22cba 2147 2145 2013-08-20T12:30:52Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:8_LAJPE_525_Ramon_Gomez_Preprint_corr_f.pdf | Low cot instrumentation for spin-coating deposition of thin films in an undergraduate laboratory]]''', Ramon Gómez Aguilar, Jaime Ortiz López. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://web.ebscohost.com/ehost/detail?sid=e899b960-fa67-462d-9460-58064bcdc673%40sessionmgr110&vid=1&hid=124&bdata=JkF1dGhUeXBlPWlwLGNvb2tpZSx1cmwsdWlkJmxhbmc9ZXMmc2l0ZT1laG9zdC1saXZl#db=aph&AN=60208346 An aqueous photopolymer for classroom holography]''', J. Blyth. (Click on the "Texto completo en PDF" link to download.) * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * A few papers by Dinesh Padiyar. ** '''[[Media:grains.pdf | Silver Halide Materials]]''' (the "grains.pdf" document). ** '''[[Media:Colour.pdf | Colour]],''' relating to color sensitivity of human eye. ** '''[[Media: Aberrations_in_Holography.pdf ‎| Aberrations in Holography]],''' coauthor Joy Padiyar. * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. * '''[[Media:Kock-LasersHolography.pdf | Lasers and Holography]],''' William Kock. * '''[[Media:kaveh-PhD.pdf | Techniques in Display Holography]],''' Kaveh Bazargan, PhD thesis, University of London, April 1986. 34a982fda0d282e205719a5c0959e12c1c89322a 0 820 2142 1991 2013-08-08T01:57:14Z Jsfisher 1 /* Overview of the Process */ wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. They are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if the hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. A common method to seal the hologram is to epoxy a second glass plate to the back of the hologram plate, thereby protecting it from moisture. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html [[Category:DCG]] [[Category:Beginner]] 4af891c5ad81f05d13c7c8b71b101f34fb35a2c7 6 906 2143 2013-08-09T18:30:00Z Dinesh 3 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 907 2144 2013-08-18T05:04:39Z Jsfisher 1 An aqueous photopolymer for classroom holography. J. Blyth. wikitext text/x-wiki An aqueous photopolymer for classroom holography. J. Blyth. 174a4d8682b4799bfa97b7f4db4f099f9f86f0ae 2146 2144 2013-08-18T05:36:01Z Jsfisher 1 Jsfisher uploaded a new version of &quot;[[File:60208346.pdf]]&quot; wikitext text/x-wiki An aqueous photopolymer for classroom holography. J. Blyth. 174a4d8682b4799bfa97b7f4db4f099f9f86f0ae 0 908 2148 2013-09-23T01:02:05Z Jsfisher 1 Created page with "The following are the comments of Ed Wesly for the two most common developers, CW-C2 and Pyrochrome, when used in combination with the two most common bleaches, the rehalogena..." wikitext text/x-wiki The following are the comments of Ed Wesly for the two most common developers, CW-C2 and Pyrochrome, when used in combination with the two most common bleaches, the rehalogenating copper sulfate and the solvent pyrochorme. {| class="wikitable" border="1" |- ! Developer ! Time ! Bleach ! Result |- | CW-C2 | 1 to 4 minutes @ 20°C | Copper Sulfate | Non-shrinking regimen keeps the replay color of reflection holograms exactly the same color as the laser's. Can be used for image-planing, contact copying, or real-time reflection interferometry. For laser transmissions gives excellent brightness and S/N ration with replay angle same as the recording reference angle. For white light transmission the bluish scatter may be objectionable for those who seek that perfectly clear window aesthetic. |- | CW-C2 | 1 to 4 minutes @ 20°C | Pyrochrome | Yields orange to green reflection holograms depending on developed density—more density gives shorter wavelength replay. Shrinkage can cause change in reference angle for transmission holograms. Plate is totally clear after process. |- | Pyrochrome | | Copper Sulfate | Not recommended. |- | Pyrochrome | 1 to 4 minutes @ 20°C | Pyrochrome | Yields red to green reflection holograms depending on developed density similar to the CW-C2/Pyrochrome combination. some change in reference angle for transmission holograms. Holograms have characteristic tan color, which helps reduce grain noise. Tan color can be removed with S-13 Stain Remover. |} db866681f6cecd71648f1a68df8076517f5145c2 2149 2148 2013-09-23T01:03:06Z Jsfisher 1 wikitext text/x-wiki The following are the comments of Ed Wesly for the two most common developers, CW-C2 and Pyrochrome, when used in combination with the two most common bleaches, the rehalogenating copper sulfate and the solvent pyrochorme. {| class="wikitable" border="1" |- ! Developer ! Time ! Bleach ! Result |- | CW-C2 | 1 to 4 minutes @ 20°C | Copper Sulfate | Non-shrinking regimen keeps the replay color of reflection holograms exactly the same color as the laser's. Can be used for image-planing, contact copying, or real-time reflection interferometry. For laser transmissions gives excellent brightness and signal-to-noise ratio with replay angle same as the recording reference angle. For white light transmission the bluish scatter may be objectionable for those who seek that perfectly clear window aesthetic. |- | CW-C2 | 1 to 4 minutes @ 20°C | Pyrochrome | Yields orange to green reflection holograms depending on developed density—more density gives shorter wavelength replay. Shrinkage can cause change in reference angle for transmission holograms. Plate is totally clear after process. |- | Pyrochrome | | Copper Sulfate | Not recommended. |- | Pyrochrome | 1 to 4 minutes @ 20°C | Pyrochrome | Yields red to green reflection holograms depending on developed density similar to the CW-C2/Pyrochrome combination. some change in reference angle for transmission holograms. Holograms have characteristic tan color, which helps reduce grain noise. Tan color can be removed with S-13 Stain Remover. |} 0f93a8ad66eabdb937f06c4961c61d6f2d544cdf 6 909 2150 2013-09-24T01:35:15Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 910 2151 2013-09-24T01:35:20Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 911 2152 2013-09-24T01:35:42Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 912 2153 2013-09-24T01:35:46Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 913 2154 2013-09-24T01:35:54Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 914 2155 2013-09-24T01:35:58Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 915 2156 2013-09-24T01:36:06Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 916 2157 2013-09-24T01:36:14Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 917 2158 2013-09-24T01:36:31Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 918 2159 2013-09-24T01:36:40Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 919 2160 2013-09-24T01:36:43Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 920 2161 2013-09-24T01:36:59Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 921 2162 2013-09-24T01:37:06Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 922 2163 2013-09-24T01:37:09Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 923 2164 2013-09-24T01:37:16Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 924 2165 2013-09-24T01:37:19Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 925 2166 2013-09-24T01:52:04Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 926 2167 2013-09-24T01:52:05Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 927 2168 2013-09-24T01:52:06Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 928 2169 2013-09-24T01:52:06Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 929 2170 2013-09-24T01:52:09Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 930 2171 2013-09-24T01:52:10Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 931 2172 2013-09-24T01:52:11Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 932 2173 2013-09-24T01:52:11Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 933 2174 2013-09-24T01:52:12Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 934 2175 2013-09-24T01:52:12Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 935 2176 2013-09-24T01:52:13Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 936 2177 2013-09-24T01:52:13Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 937 2178 2013-09-24T01:52:14Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 938 2179 2013-09-24T01:52:14Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 939 2180 2013-09-24T01:52:15Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 940 2181 2013-09-24T01:52:16Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 941 2182 2013-09-24T02:29:22Z Jsfisher 1 Created page with "Copyright Ed Wesly Reproduced with permission == Spherical Aberration == '''Explanation:''' Due to the geometry of spherical surfaces, rays from a particular point on an obj..." wikitext text/x-wiki Copyright Ed Wesly Reproduced with permission == Spherical Aberration == '''Explanation:''' Due to the geometry of spherical surfaces, rays from a particular point on an object passing through the edge of a lens focus nearer to the lens than do the paraxial rays. [[File:340Aberrations 1.png|thumb|400px|Figure 1]] In the top half of Figure 1, the ideal ray trace shows that all rays from the same infinite object point arrive at the same focal point. Below that is shown the typical ''sperically aberrated'' case, where the marginal rays from the edge of the lens come to a focus nearer to the lens than the centrally located paraxial rays. This is simply a consequence of applying Snell's Law to all the points of a spherically curved surface; the rays hitting the peripheries of the lens are incident at larger and larger angles, and the beams will be bent much too strongly to match those coming in through the center. [[File:340Aberrations 2.png|400px|thumb|Figure 2]] The extent of SA can be measured linearly in two dimensions: along the optical axis, the ''Longitudinal Spherical Aberration'' (LSA in Figure 2), which is the distance from the paraxial focus to the focal point of the marginal rays; or at right angles to the optical axis, the ''Transverse Spherical Aberration'' (TSA in the figure), which is measured in the focal plane containing the paraxial focus to where the marginal ray intercepts the focal plane. The "miss" angle between the actual path of the marginal ray and its intended path to the paraxial focus is another possible measure of the degree of SA. [[File:340Aberrations 3.png|400px|thumb|Figure 3]] An outline of the rays leaving the lens and headed to their respective foci is labelled the ''caustic curve'' in Figure 2. Where the marginal rays cross the caustic is the smallest circle of confusion, as after that the marginal rays are expanding the diameter of the circle of confusion. The image at the paraxial focus will look like a bright nucleus with a hazy halo thanks to the marginal rays; the circle of least confusion will have maximum contrast and will be a small patch of light. Since the marginal rays define the position of the smallest circle of confusion, the position of the best focus will change as a spherically aberrated lens is stopped down. The new marginal rays defined by the aperture meet the caustic closer to the paraxial focus, so it seems that the object has moved closer to the lens since the new focal plane is further from the lens. [[File:340Aberrations 4.png|400px|thumb|Figure 4]] Figure 4 compares the SA of positive and negative lenses. Notice that in both cases the marginal rays bend quicker than paraxial rays so that the marginal focal point is shifted closer to the lens. This makes the marginal rays more convergent or more divergent. When the marginal rays are inside the paraxial ones, this condition is termed ''undercorrected spherical aberration''; the "outside" divergent rays of the negative lens are said to be ''overcorrected''. It can be predicted from the figure that when observing SA in the virtual image of a negative lens, the image spot will move toward the lens as the point of observation moves further off-axis. The reverse happens in the real image of a positive lens, where the marginal rays move the image closer to the lens, away from the viewer. [[File:340Aberrations 5.png|400px]][[File:340Aberrations 6.png|400px]][[File:340Aberrations 7.png|400px]][[File:340Aberrations 8.png|400px]][[File:340Aberrations 9.png|400px]][[File:340Aberrations 10.png|400px]][[File:340Aberrations 11.png|400px]][[File:340Aberrations 12.png|400px]][[File:340Aberrations 13.png|400px]][[File:340Aberrations 14.png|400px]][[File:340Aberrations 15.png|400px]][[File:340Aberrations 16.png|400px]] 4741898cef0d6b46876c3778742cc0a34d961ffa 6 942 2183 2013-09-24T02:31:42Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 875 2184 2147 2013-09-24T02:36:29Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:340Aberrations.pdf | The Seven Deadly Aberrations]]''', Ed Wesley provides a detailed discussion of seven aberration effects. * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:8_LAJPE_525_Ramon_Gomez_Preprint_corr_f.pdf | Low cot instrumentation for spin-coating deposition of thin films in an undergraduate laboratory]]''', Ramon Gómez Aguilar, Jaime Ortiz López. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://web.ebscohost.com/ehost/detail?sid=e899b960-fa67-462d-9460-58064bcdc673%40sessionmgr110&vid=1&hid=124&bdata=JkF1dGhUeXBlPWlwLGNvb2tpZSx1cmwsdWlkJmxhbmc9ZXMmc2l0ZT1laG9zdC1saXZl#db=aph&AN=60208346 An aqueous photopolymer for classroom holography]''', J. Blyth. (Click on the "Texto completo en PDF" link to download.) * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * A few papers by Dinesh Padiyar. ** '''[[Media:grains.pdf | Silver Halide Materials]]''' (the "grains.pdf" document). ** '''[[Media:Colour.pdf | Colour]],''' relating to color sensitivity of human eye. ** '''[[Media: Aberrations_in_Holography.pdf ‎| Aberrations in Holography]],''' coauthor Joy Padiyar. * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. * '''[[Media:Kock-LasersHolography.pdf | Lasers and Holography]],''' William Kock. * '''[[Media:kaveh-PhD.pdf | Techniques in Display Holography]],''' Kaveh Bazargan, PhD thesis, University of London, April 1986. 2f31960b01bf23493d592e8de8585c7fd5f8d05f 2200 2184 2013-12-20T01:39:43Z Jsfisher 1 wikitext text/x-wiki * '''[[Media:340Aberrations.pdf | The Seven Deadly Aberrations]]''', Ed Wesly provides a detailed discussion of seven aberration effects. * '''[[Media:GMIA_Gelatin_Manual_2012.pdf | Gelatin Handbook]]''', Gelatin Manufacturers Institute of America. * '''[[Media:8_LAJPE_525_Ramon_Gomez_Preprint_corr_f.pdf | Low cot instrumentation for spin-coating deposition of thin films in an undergraduate laboratory]]''', Ramon Gómez Aguilar, Jaime Ortiz López. * '''[[Media:Sympos2006.pdf | Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light]]''', Jeff Blyth, Christopher R. Lowe, John F. Pecora. * '''[[Media:223_1.pdf | Making Holograms in Middle and High Schools]]''', Tung H. Jeong. * '''[http://web.ebscohost.com/ehost/detail?sid=e899b960-fa67-462d-9460-58064bcdc673%40sessionmgr110&vid=1&hid=124&bdata=JkF1dGhUeXBlPWlwLGNvb2tpZSx1cmwsdWlkJmxhbmc9ZXMmc2l0ZT1laG9zdC1saXZl#db=aph&AN=60208346 An aqueous photopolymer for classroom holography]''', J. Blyth. (Click on the "Texto completo en PDF" link to download.) * '''[http://archive.org/details/TheTheoryOfThePhotographicProcess The Theory of the Photograpic Process],''' C.E. Kenneth Mees. (Very large file.) * '''[[Media:laserprimer.pdf | Diode Laser Characteristics]],''' Ph 77 Advanced Physics Laboratory, Atomic and Optical Physics, California Institute of Technology. * A few papers by Dinesh Padiyar. ** '''[[Media:grains.pdf | Silver Halide Materials]]''' (the "grains.pdf" document). ** '''[[Media:Colour.pdf | Colour]],''' relating to color sensitivity of human eye. ** '''[[Media: Aberrations_in_Holography.pdf ‎| Aberrations in Holography]],''' coauthor Joy Padiyar. * '''[[Media:Dye_sensitization_of_holographic_emulsions.pdf | Dye Sensitization of Holographic Emulsions]],''' D. Bruza, D. Padiyar. * '''[[Media:Z. Coleman - Dichromated gelatin.pdf | Dichromated Gelatin &mdash; some heretical comments]],''' Nicholas J. Phillips, Richard D. Rallison, Christopher A. Barnett, Scott R. Schicker, Zane A. Coleman. * '''[[Media:Kock-LasersHolography.pdf | Lasers and Holography]],''' William Kock. * '''[[Media:kaveh-PhD.pdf | Techniques in Display Holography]],''' Kaveh Bazargan, PhD thesis, University of London, April 1986. 5a8325270232c740ab8037b66b5c6d79edca3b88 0 1 2185 2137 2013-09-24T02:40:11Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. == New Stuff and Recent Additions == * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the [[Reading Room]]. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). <!-- * [[Archives|Archives]] --> 037c7ea2f5d85cfd548afeed97e802252425deee 2190 2185 2013-10-04T02:01:57Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|[[Gallery]]]] == New Stuff and Recent Additions == * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the [[Reading Room]]. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). <!-- * [[Archives|Archives]] --> 4fca5ce4f14d3a567c97f90fe338d2ac62ace8bc 2191 2190 2013-10-04T02:03:17Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the [[Reading Room]]. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). <!-- * [[Archives|Archives]] --> 5cf7ba3238d17b7dd5996616e4e74235678b42c2 2195 2191 2013-10-08T00:03:08Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * A new ''My First...'' entry in the DCG section of the [[Gallery]]. * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the [[Reading Room]]. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). <!-- * [[Archives|Archives]] --> 61d93acee1ff355619ee46a5000f38d6451d2fa6 2196 2195 2013-10-13T04:37:06Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * A new ''My First...'' entry in the DCG section of the [[Gallery]]. * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the [[Reading Room]]. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 75bc3aa20f4e353857c7b525288d043da84262cb 2199 2196 2013-11-29T04:45:00Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * [[DCG Color Tuning]] guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the [[Gallery]]. * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the [[Reading Room]]. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 071654e0ad4c3d6921088f164a47fcd4bf70c080 0 808 2186 1597 2013-09-24T03:48:37Z Jsfisher 1 wikitext text/x-wiki [[Image:Sandbox_Kit.jpg|right]]The "original" hobbyist's approach to holography was described in the May 1979 issue of ''Physics Education'' as the aptly named ''Sandbox Holography''. Metrologic produced and sold an identically named kit. The kit included some holographic film, chemicals for processing the film, and few lenses and mirrors. Not included were the laser (and at the time, that meant a moderately pricey helium-neon gas laser) nor the sandbox. Holography is extremely sensitive to movement, even microscopic movement, during the exposure. In conventional photography, movement will blur the image. With a hologram, since movement would completely alter the interference pattern between the direct and reflected laser light, the image can be lost completely. The sandbox was used to help eliminate vibration. In the late 1970's and early 1980's, the Metrologic Instruments Sandbox Holography kit might have cost you $150(US). A suitable laser, another $400 or so, and by the time you had the sandbox set up, you would be out $600 to $700 in 1980 dollars. For the curious, an updated version of the kit is still available from [http://i-fiberoptics.com/laser-kits-projects-detail.php?id=2140 Industrial Fiber Optics]. Industrial Fiber Optics purchased the educational laser and kit product line from Metrologic Instruments in November 2004. Although the [http://i-fiberoptics.com/pdf/45-733a_manual-revc.pdf Sandbox Holography] manual has details specific to the sandbox kit, it still provides a general introduction to holography for the beginner. == Modern Beginner's Kit == [[Image:Integraf_kit.jpg|right]]Diode lasers, like the ones found in common laser pointers, have completely changed what is needed for a suitable beginner's kit. You still need film and processing chemicals, but your first hologram can be made with no additional lenses or mirrors (because the diode laser beam naturally spreads), and there are some simple techniques developed over the years since the Sandbox kit was first introduced to eliminate the sandbox. In the new era, sandbox holography has evolved into [http://www.holoworld.com/shoebox/ Shoebox Holography], and there are now three, relatively economic ways for novice holographers to begin their hobby. #Buy the ''Shoebox Holography'' book. With that as a guide (or the equivalent information scoured from the Internet) acquire a suitable laser, holographic film, and chemicals and have at it. #Acquire one of the kits available from [http://www.integraf.com/holography_kit.htm Integraf]. (Film is more difficult to work with than glass plates, so the Standard or Student Kit is much preferred over the Budget Kit.) #Acquire a diffent type of kit from [http://www.litiholo.com Litiholo]. For the truly novice holographer, the Litiholo kit is a a bit of an oddity. With it, you can produce your first, interesting hologram. The kit comes with 20 plates, so there is plenty of opportunity for experimentation and the inevitable failure. Be aware, though, it is a self-contained unit. The holographic plates are self-developing, and the configuration is limited to the setups the kit intended. For the mildly curious individual or the elementary school aged child, the Litiholo kit is fabulous. For the slightly experienced holographer, it is good, if for nothing else than the exposure to polymer photo-materials. For the true beginner, though, it is a little like buying a TV dinner because you wanted to learn to cook. There is not enough "participation" to engage the beginner. Of the remaining two choices, simply buying a kit from Integraf saves you all the hassle of acquiring the parts individual. Plus you end up with a higher quality laser than what you would get from laser pointer. Some laser pointers have stability issues that may be unnoticeable in normal use, but disastrous in holography. The information that comes with the Integraf kit, or the identical [http://www.integraf.com/a-simple_holography.htm material available from the Integraf web site], or similar articles online, or from texts like the ''Shoebox Holography'' book, covers what to do next. Not much to it, really. == Beginner's FAQ == ; What is a hologram? : Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ; How little money/bother do I need to make one? : You can make your first hologram with about 2 hours of set up and about $100. ; What is the cheapest way to make a hologram? : [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ; Are the chemicals dangerous? : While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ; What sort of time commitment is there for making a hologram? : You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ; When can I have the lights 'on' during the procedure of making a hologram? : Once the emulsion has become insensitive to to light. For silver-halide holograms this is after the hologram is bleached. For dichromated gelatin holograms this is after the fixing and rinsing steps. ; What are the different kinds of holograms? : [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ; What is the single most important factor when making a hologram? : ''Stability!'' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ; How Does a LASER work? : For a simple introduction to lasers read [[How Do LASERs work?]]. ; Can I use a cheap red laser pointer to make holograms? : Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ; Can I use a Green Laser Pointer to make holograms? : So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ; Where are the Reference and Object beams in a Single Beam Reflection Hologram? : Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ; Some uses for [[Everyday Items]] in holography : Click here for [[Everyday Items]] that can save you money in holography! ; What is a [[Scratch-O-Gram]]? : A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and focusing it from a curved scratch to a point. ; What Books are Available for Holography? : See the [[Books]] section. [[Category:Beginner]] 7f233737ca68e400dae12b1aa37e47e097c3f9ab 2187 2186 2013-09-24T03:49:35Z Jsfisher 1 /* Modern Beginner's Kit */ wikitext text/x-wiki [[Image:Sandbox_Kit.jpg|right]]The "original" hobbyist's approach to holography was described in the May 1979 issue of ''Physics Education'' as the aptly named ''Sandbox Holography''. Metrologic produced and sold an identically named kit. The kit included some holographic film, chemicals for processing the film, and few lenses and mirrors. Not included were the laser (and at the time, that meant a moderately pricey helium-neon gas laser) nor the sandbox. Holography is extremely sensitive to movement, even microscopic movement, during the exposure. In conventional photography, movement will blur the image. With a hologram, since movement would completely alter the interference pattern between the direct and reflected laser light, the image can be lost completely. The sandbox was used to help eliminate vibration. In the late 1970's and early 1980's, the Metrologic Instruments Sandbox Holography kit might have cost you $150(US). A suitable laser, another $400 or so, and by the time you had the sandbox set up, you would be out $600 to $700 in 1980 dollars. For the curious, an updated version of the kit is still available from [http://i-fiberoptics.com/laser-kits-projects-detail.php?id=2140 Industrial Fiber Optics]. Industrial Fiber Optics purchased the educational laser and kit product line from Metrologic Instruments in November 2004. Although the [http://i-fiberoptics.com/pdf/45-733a_manual-revc.pdf Sandbox Holography] manual has details specific to the sandbox kit, it still provides a general introduction to holography for the beginner. == Modern Beginner's Kit == [[Image:Integraf_kit.jpg|right]]Diode lasers, like the ones found in common laser pointers, have completely changed what is needed for a suitable beginner's kit. You still need film and processing chemicals, but your first hologram can be made with no additional lenses or mirrors (because the diode laser beam naturally spreads), and there are some simple techniques developed over the years since the Sandbox kit was first introduced to eliminate the sandbox. In the new era, sandbox holography has evolved into [http://www.holoworld.com/shoebox/ Shoebox Holography], and there are now three, relatively economic ways for novice holographers to begin their hobby. #Buy the ''Shoebox Holography'' book. With that as a guide (or the equivalent information scoured from the Internet) acquire a suitable laser, holographic film, and chemicals and have at it. #Acquire one of the kits available from [http://www.integraf.com/holography_kit.htm Integraf]. (Film is more difficult to work with than glass plates, so the Standard or Student Kit is much preferred over the Budget Kit.) #Acquire a different type of kit from [http://www.litiholo.com Litiholo]. For the truly novice holographer, the Litiholo kit is a a bit of an oddity. With it, you can produce your first, interesting hologram. The kit comes with 20 plates, so there is plenty of opportunity for experimentation and the inevitable failure. Be aware, though, it is a self-contained unit. The holographic plates are self-developing, and the configuration is limited to the setups the kit intended. For the mildly curious individual or the elementary school aged child, the Litiholo kit is fabulous. For the slightly experienced holographer, it is good, if for nothing else than the exposure to polymer photo-materials. For the true beginner, though, it is a little like buying a TV dinner because you wanted to learn to cook. There is not enough "participation" to engage the beginner. Of the remaining two choices, simply buying a kit from Integraf saves you all the hassle of acquiring the parts individual. Plus you end up with a higher quality laser than what you would get from laser pointer. Some laser pointers have stability issues that may be unnoticeable in normal use, but disastrous in holography. The information that comes with the Integraf kit, or the identical [http://www.integraf.com/a-simple_holography.htm material available from the Integraf web site], or similar articles online, or from texts like the ''Shoebox Holography'' book, covers what to do next. Not much to it, really. == Beginner's FAQ == ; What is a hologram? : Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ; How little money/bother do I need to make one? : You can make your first hologram with about 2 hours of set up and about $100. ; What is the cheapest way to make a hologram? : [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ; Are the chemicals dangerous? : While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ; What sort of time commitment is there for making a hologram? : You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ; When can I have the lights 'on' during the procedure of making a hologram? : Once the emulsion has become insensitive to to light. For silver-halide holograms this is after the hologram is bleached. For dichromated gelatin holograms this is after the fixing and rinsing steps. ; What are the different kinds of holograms? : [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ; What is the single most important factor when making a hologram? : ''Stability!'' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ; How Does a LASER work? : For a simple introduction to lasers read [[How Do LASERs work?]]. ; Can I use a cheap red laser pointer to make holograms? : Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ; Can I use a Green Laser Pointer to make holograms? : So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ; Where are the Reference and Object beams in a Single Beam Reflection Hologram? : Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ; Some uses for [[Everyday Items]] in holography : Click here for [[Everyday Items]] that can save you money in holography! ; What is a [[Scratch-O-Gram]]? : A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and focusing it from a curved scratch to a point. ; What Books are Available for Holography? : See the [[Books]] section. [[Category:Beginner]] d95d5338b3caa03971c044f8bff332679bd2f0e3 2188 2187 2013-09-24T03:51:13Z Jsfisher 1 /* Modern Beginner's Kit */ wikitext text/x-wiki [[Image:Sandbox_Kit.jpg|right]]The "original" hobbyist's approach to holography was described in the May 1979 issue of ''Physics Education'' as the aptly named ''Sandbox Holography''. Metrologic produced and sold an identically named kit. The kit included some holographic film, chemicals for processing the film, and few lenses and mirrors. Not included were the laser (and at the time, that meant a moderately pricey helium-neon gas laser) nor the sandbox. Holography is extremely sensitive to movement, even microscopic movement, during the exposure. In conventional photography, movement will blur the image. With a hologram, since movement would completely alter the interference pattern between the direct and reflected laser light, the image can be lost completely. The sandbox was used to help eliminate vibration. In the late 1970's and early 1980's, the Metrologic Instruments Sandbox Holography kit might have cost you $150(US). A suitable laser, another $400 or so, and by the time you had the sandbox set up, you would be out $600 to $700 in 1980 dollars. For the curious, an updated version of the kit is still available from [http://i-fiberoptics.com/laser-kits-projects-detail.php?id=2140 Industrial Fiber Optics]. Industrial Fiber Optics purchased the educational laser and kit product line from Metrologic Instruments in November 2004. Although the [http://i-fiberoptics.com/pdf/45-733a_manual-revc.pdf Sandbox Holography] manual has details specific to the sandbox kit, it still provides a general introduction to holography for the beginner. == Modern Beginner's Kit == [[Image:Integraf_kit.jpg|right]]Diode lasers, like the ones found in common laser pointers, have completely changed what is needed for a suitable beginner's kit. You still need film and processing chemicals, but your first hologram can be made with no additional lenses or mirrors (because the diode laser beam naturally spreads), and there are some simple techniques developed over the years since the Sandbox kit was first introduced to eliminate the sandbox. In the new era, sandbox holography has evolved into [http://www.holoworld.com/shoebox/ Shoebox Holography], and there are now three, relatively economic ways for novice holographers to begin their hobby. #Buy the ''Shoebox Holography'' book. With that as a guide (or the equivalent information scoured from the Internet) acquire a suitable laser, holographic film, and chemicals and have at it. #Acquire one of the kits available from [http://www.integraf.com/holography_kit.htm Integraf]. (Film is more difficult to work with than glass plates, so the Standard or Student Kit is much preferred over the Budget Kit.) #Acquire a different type of kit from [http://www.litiholo.com Litiholo]. For the truly novice holographer, the Litiholo kit is a a bit of an oddity. With it, you can produce your first, interesting hologram. The kit comes with 20 plates, so there is plenty of opportunity for experimentation and the inevitable failure. Be aware, though, it is a self-contained unit. The holographic plates are self-developing, and the configuration is limited to the setups the kit intended. For the mildly curious individual or the elementary school aged child, the Litiholo kit is fabulous. For the slightly experienced holographer, it is good, if for nothing else than the exposure to polymer photo-materials. For the true beginner, though, it is a little like buying a TV dinner because you wanted to learn to cook. There is not enough "participation" to engage the beginner. Of the remaining two choices, simply buying a kit from Integraf saves you all the hassle of acquiring the parts individually. Plus you end up with a higher quality laser than what you would get from laser pointer. Some laser pointers have stability issues that may be unnoticeable in normal use, but disastrous in holography. The information that comes with the Integraf kit, or the identical [http://www.integraf.com/a-simple_holography.htm material available from the Integraf web site], or similar articles online, or from texts like the ''Shoebox Holography'' book, covers what to do next. Not much to it, really. == Beginner's FAQ == ; What is a hologram? : Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ; How little money/bother do I need to make one? : You can make your first hologram with about 2 hours of set up and about $100. ; What is the cheapest way to make a hologram? : [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ; Are the chemicals dangerous? : While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ; What sort of time commitment is there for making a hologram? : You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ; When can I have the lights 'on' during the procedure of making a hologram? : Once the emulsion has become insensitive to to light. For silver-halide holograms this is after the hologram is bleached. For dichromated gelatin holograms this is after the fixing and rinsing steps. ; What are the different kinds of holograms? : [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ; What is the single most important factor when making a hologram? : ''Stability!'' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ; How Does a LASER work? : For a simple introduction to lasers read [[How Do LASERs work?]]. ; Can I use a cheap red laser pointer to make holograms? : Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ; Can I use a Green Laser Pointer to make holograms? : So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ; Where are the Reference and Object beams in a Single Beam Reflection Hologram? : Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ; Some uses for [[Everyday Items]] in holography : Click here for [[Everyday Items]] that can save you money in holography! ; What is a [[Scratch-O-Gram]]? : A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and focusing it from a curved scratch to a point. ; What Books are Available for Holography? : See the [[Books]] section. [[Category:Beginner]] 0c20e9bdd3177839bf32e57baa813596056c073b 2189 2188 2013-09-24T03:52:20Z Jsfisher 1 /* Modern Beginner's Kit */ wikitext text/x-wiki [[Image:Sandbox_Kit.jpg|right]]The "original" hobbyist's approach to holography was described in the May 1979 issue of ''Physics Education'' as the aptly named ''Sandbox Holography''. Metrologic produced and sold an identically named kit. The kit included some holographic film, chemicals for processing the film, and few lenses and mirrors. Not included were the laser (and at the time, that meant a moderately pricey helium-neon gas laser) nor the sandbox. Holography is extremely sensitive to movement, even microscopic movement, during the exposure. In conventional photography, movement will blur the image. With a hologram, since movement would completely alter the interference pattern between the direct and reflected laser light, the image can be lost completely. The sandbox was used to help eliminate vibration. In the late 1970's and early 1980's, the Metrologic Instruments Sandbox Holography kit might have cost you $150(US). A suitable laser, another $400 or so, and by the time you had the sandbox set up, you would be out $600 to $700 in 1980 dollars. For the curious, an updated version of the kit is still available from [http://i-fiberoptics.com/laser-kits-projects-detail.php?id=2140 Industrial Fiber Optics]. Industrial Fiber Optics purchased the educational laser and kit product line from Metrologic Instruments in November 2004. Although the [http://i-fiberoptics.com/pdf/45-733a_manual-revc.pdf Sandbox Holography] manual has details specific to the sandbox kit, it still provides a general introduction to holography for the beginner. == Modern Beginner's Kit == [[Image:Integraf_kit.jpg|right]]Diode lasers, like the ones found in common laser pointers, have completely changed what is needed for a suitable beginner's kit. You still need film and processing chemicals, but your first hologram can be made with no additional lenses or mirrors (because the diode laser beam naturally spreads), and there are some simple techniques developed over the years since the Sandbox kit was first introduced to eliminate the sandbox. In the new era, sandbox holography has evolved into [http://www.holoworld.com/shoebox/ Shoebox Holography], and there are now three, relatively economic ways for novice holographers to begin their hobby. #Buy the ''Shoebox Holography'' book. With that as a guide (or the equivalent information scoured from the Internet) acquire a suitable laser, holographic film, and chemicals and have at it. #Acquire one of the kits available from [http://www.integraf.com/holography_kit.htm Integraf]. (Film is more difficult to work with than glass plates, so the Standard or Student Kit is much preferred over the Budget Kit.) #Acquire a different type of kit from [http://www.litiholo.com Litiholo]. For the truly novice holographer, the Litiholo kit is a a bit of an oddity. With it, you can produce your first, interesting hologram. The kit comes with 20 plates, so there is plenty of opportunity for experimentation and the inevitable failure. Be aware, though, it is a self-contained unit. The holographic plates are self-developing, and the configuration is limited to the setups the kit intended. For the mildly curious individual or the elementary school aged child, the Litiholo kit is fabulous. For the slightly experienced holographer, it is good, if for nothing else than the exposure to polymer photo-materials. For the true beginner, though, it is a little like buying a TV dinner because you wanted to learn to cook. There is not enough "participation" to engage the beginner. Of the remaining two choices, simply buying a kit from Integraf saves you all the hassle of acquiring the parts individually. Plus you end up with a higher quality laser than what you would get from an ordinary laser pointer. Some laser pointers have stability issues that may be unnoticeable in normal use, but disastrous in holography. The information that comes with the Integraf kit, or the identical [http://www.integraf.com/a-simple_holography.htm material available from the Integraf web site], or similar articles online, or from texts like the ''Shoebox Holography'' book, covers what to do next. Not much to it, really. == Beginner's FAQ == ; What is a hologram? : Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ; How little money/bother do I need to make one? : You can make your first hologram with about 2 hours of set up and about $100. ; What is the cheapest way to make a hologram? : [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ; Are the chemicals dangerous? : While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ; What sort of time commitment is there for making a hologram? : You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ; When can I have the lights 'on' during the procedure of making a hologram? : Once the emulsion has become insensitive to to light. For silver-halide holograms this is after the hologram is bleached. For dichromated gelatin holograms this is after the fixing and rinsing steps. ; What are the different kinds of holograms? : [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ; What is the single most important factor when making a hologram? : ''Stability!'' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ; How Does a LASER work? : For a simple introduction to lasers read [[How Do LASERs work?]]. ; Can I use a cheap red laser pointer to make holograms? : Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ; Can I use a Green Laser Pointer to make holograms? : So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ; Where are the Reference and Object beams in a Single Beam Reflection Hologram? : Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ; Some uses for [[Everyday Items]] in holography : Click here for [[Everyday Items]] that can save you money in holography! ; What is a [[Scratch-O-Gram]]? : A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and focusing it from a curved scratch to a point. ; What Books are Available for Holography? : See the [[Books]] section. [[Category:Beginner]] 0c73f197556d886620494092695706d61db759ce 6 943 2192 2013-10-07T23:18:37Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 944 2193 2013-10-07T23:18:38Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 826 2194 1685 2013-10-07T23:21:39Z Jsfisher 1 /* Dichromated Gelatin */ wikitext text/x-wiki == Silver Halide Films and Plates == === Workin' out with Irena === {| |- | Tom B.: Same plates and technique as usual (BB-640, 6% TEA, lit for photo with OptiLed amber from about 1.5 m). The pics didn't come out as well this time, but good enough. The fringe pattern under the models is intentional - I calculated a mickey-mouse model of spherical wavefront interference and printed it out on cardstock as a background, but alas it moved a bit so it's dark under Irena's hand. [[File:Olympic.jpg|400px]] Here is a stereoscopic pair photographed from the hologram. Look through the image to get the two halves to merge into a single image. [[File:Olympic_stereo.jpg|400px]] More of Tom B.'s work is show-cased at http://members.shaw.ca/holopix/My_holograms.html, complete with a chronology of his ever-improving efforts. |} === My First... === {| | PeterZ: This is my first reflection hologram using Integraf holokit, with PFG-01. Exposure time was 25s, distance between laser and plate 37 cm. Not very good photo. I'll do another one using polarizing filter and camera with manual focus. [[File:PeterZ_first.jpg|400px]] |} == Litiholo Kit == === Simple Transmission of Car === {| |- | Transmission hologram by Arturo with Litiholo kit. [[File:Arturo_Liti_car1.jpg|250px]] [[File:Arturo_Liti_car2.jpg|250px]] |} == Dichromated Gelatin == === My First 4" X 5" DCG Hologram === http://holoforum.org/forum/viewtopic.php?f=7&t=764 {| | Stephen: Mold-coated with 240 bloom skin gelatin brought from eBay. Dissolved 7.5 g of gelatin in 50 ml deionized water heated to 40-45° C, then filtered the gelatin using filter paper and small funnel. I used 60 μm shims and 6 mm thick 15" x 4" float glass for the mold. Mold was treated with Rain-X and then heated with hair dryer prior to pouring gelatin. I soaked 2 mm x 15" x 4" float glass in a 5% hydrochloric acid solution (concrete path cleaner) for 24 hours. The glass was then scrubbed under running water, and then rinsed with deionized water. Finally, I treated the 2 mm float glass with silane, TOTALSEAL 7016 (used for epoxying glass). After pouring the gelatin and clamping the mold, I waited until the mold had cooled to the ambient temperature, then placed in the mold into the refrigerator for five hours. [Note: 30 minutes would have been sufficient for the gelatin to set.] Then the mold was removed from the refrigerator and the parted the plates. The gelatin-coated plate was allowed to air-dry at ambient temperature for 24 hours. The plate was then cut into three 5" sections. The plates were then dip coated in a 3% solution of Ammonium Dichromate (15 g AmDi dissolved in 500 ml deionized water and 5 ml Ilford Ilfotol). The plates air dried at ambient room temperature for 5 hours. The platers were exposed at 532 nm with a ref power density at the center of the plate measured as 432 mJ. My measured power takes into consideration the loss due to Brewster's angle, but no measurement of object beam power. I gave five minutes for dark reaction, then proceeded with the following development steps. All baths at ambient. * Kodak Rapid Fixer (diluted as per paper processing) until clear + 15 seconds. * Rinse in water. * Water tuning bath for three minutes. * Dehydration in 50%, 70%, and 91% IPA, three minutes in each bath. * Dehydration in 100% until diffraction was visible + 15 seconds. The plates were then reprocessed with the following steps. The first bath at 32° C and the others at ambient room temperature. * Water tuning bath for three minutes. * 70% and 91% IPA each for 15 seconds. * 100% IPA until diffraction visible + 15 seconds. The plates were then dried with a hot hair drier followed by 20 minutes on a hotplate at 100° C. The plates were then sealed with cover glass. Notes to self: * Don't get the mold too hot. * Double check which is the emulsion side before placing the plate in processing tray. * Don't dry dipped coated plate vertically. [[File:Test fixture.jpg|400px]] [[File:HOLO 1.jpg|400px]] |} === Mermaid === {| | Colin Kaminski: This is a 4x5" dichromated geletin reflection H2 hologram that Dinesh, Joy and I made at their lab in San Diego. Here is a link to their work: http://www.tripletake.com. I helped a little but really the success of this image was the result of their skills which they were very generous about teaching me. [[File:Kaminski_mermaid.jpg|400px]] |} === Musical Angel === {| |- | John Pecora: On the left, 488 nm, 30 second exposure, fixer, water, alcohol. On the right, also 488 nm and 30 second exposure, then water for 25 seconds, then fixer, water, alcohol. Both exactly the same except the water prior to fixer soak. If you look on the right near the head in the white hologram you will see a type of whiteness and it starts to blur into the angels head on the white hologram. It seems to be where the emulsion is thin. The emulsion actually seemed to crystalized. It's not that is it cloudy but it reflects the light off the emulsion like a white haze. The more more of an angle the replay light the more diffusely reflecting the haze is and the further into the hologram it moves (all the way over to about half way across the head where it is blurry). Also what I noticed is the hologram on the left, when dried with the hot air just dried and got brighter and shifted colors. The one on the right exhibited that white crystalization (not cloudy) that then cleared up and went away to yield the hologram. [[File:JohnFP_AngelMusic.jpg|400px]] |} === Compass 215M Test === {| |- | Dave Battin plays with his Coherent 215M running at just under 30 mW. This hologram was a 6 minute exposure using one concave mirror, rapid fix. and ''dip sensitizing method''. The dip sensitizing method involves the following: * Coat gelatin onto glass and allow to harden. * Dip hardened plates into solution of AmDi (15 g), H₂O (500 ml), and soapy water (10ml). * Allow to '''air dry'''. * Expose. [[File:Battin_215M.JPG|400px]] |} === Two Color Test === {| |- | Combined red and green beams by Joe Farina. [[File:Farina_DCG_marbles.JPG|400px]] |} === Two Color Figures === {| |- | Joe Farina: These were done with Jeff's MBDCG formula, except that boric acid was used to adjust the pH, and Rhodamine 6G was used as the additional green sensitizer. The exposure was a combined 532/633 beam, with 14mW for 532 and 20mW for 633, measured after the spatial filter, the holograms are simple SBR Denisyuk. Plates are about 5 X 5 inches, and the exposures were around 20 minutes. One of the figures was painted with a few colors (very crudely), and the other figure was painted silver. The silver-painted figure helps me to get a better grip on whether the hologram (as a whole) is more narrowband or broadband. The plate on the right has a serious flaw (but also the best color reproduction) because there is a patch across the lower faces and upper chests of the two figures. This seems to be where the emulsion overheated in the oven. (I made a mistake by laving the glass directly on the inner floor of a homemade oven, I will correct that next time.) The colors came out fine. The outer robe is green, the inner garment is red, the scroll is white, the skin tone is tan, the hair is dark brown, with some lighter brown areas. I'm surprised the scroll came out so white. These two wavelengths (532 and 633) seem to be capable of reproducing a great many colors, but of course anything containing blue won't show up. I'm confident that this exact system will work very well if blue is added, for full color. [[File:Farina_DCG_figures1.jpg|400px]] [[File:Farina_DCG_figures2.jpg|400px]] [[File:Farina_DCG_figures3.jpg|400px]] |} === Little MBDCG Holo === {| |- | Hans: Here is a sample of a MBDCG that I just made with my adjustments to the original MBDCG. Due to temperature/moisture in my garage, I would never have been able to do this in my garage with classical MBDCG as was invented by Jeff Blyth because of fading (crystallizing) of the MB in the plate. Exposure time was 5 minutes with a TEC controlled laser diode. The plate was processed as follows: * First a long wash (10 minutes) in cold water to wash out the chemicals. * A swelling bath at 26C. I found that for thick coatings, this bath needs to be at least one minute. Otherwise, dim areas will appear on the hologram. * 35% IPA at 25C, two minutes * 70% IPA at 25C, two minutes * 99% IPA at 25C, three minutes I use no fixer. Remember that in classic DCG, the fixer is needed to convert the Cr(V) to Cr(III). It is the Cr(III) that hardens the fringes in the gelatin. With MBDCG it is the Methylene Blue that does that job. Cr(VI) is converted directly to Cr(III) upon illumination, and thus eliminating the need for a fixer. In previous experiments I found a great benefit in using a hardener before the swelling baths. But because my hardener was getting old so fast, I started to experiment with post exposures. I found the effect to be similar. I prefer the post exposure method over a hardening bath because it cancels out two big variables: Temperature of the hardening bath and age of the hardening chemicals. With a post exposure there is only one variable: Post exposure time. Experimentally, a post exposure time of 1/7 of the normal exposure time seems to work fine. I just wiggle the plate in the expanded laser beam at about the same distance where the plate was when the hologram was exposed. I have not found a little difference in bandwidth between post exposed plates and chemically hardened plates. Post exposed plates indeed are a little bit more broadband. But that to me is a benefit. [[File:Hans_NewFormula1.jpg|400px]] |} 92e0fcd9e43a0f794b512a99961e11520c481f8a 0 945 2197 2013-11-29T04:41:12Z Jsfisher 1 Created page with " Danny Bruza was kind enough to share this chart he had made for his own use. The chart gives the playback Danny gets for a sequence of dichromate-to-gelatin concentrations a..." wikitext text/x-wiki Danny Bruza was kind enough to share this chart he had made for his own use. The chart gives the playback Danny gets for a sequence of dichromate-to-gelatin concentrations at each of three recording wavelengths, 532nm, 514nm, and 405nm. {| class="wikitable" border="1" |- ! Di-gel ! 532nm ! 514nm ! 405nm |- | 10-30 || 532 || 514 || 405 |- | 09-30 || 552 || 533 || 424 |- | 08-30 || 571 || 552 || 443 |- | 07-30 || 590 || 571 || 462 |- | 06-30 || 609 || 590 || 481 |- | 05-30 || 628 || 609 || 500 |- | 04-30 || 647 || 628 || 519 |- | 03-30 || 666 || 647 || 538 |- | 02-30 || 685 || 666 || 557 |- | 01-30 || 704 || 685 || 576 |} Results can vary. Many, many factors come into play with dichromated gelatin. Gelatin bloom strength, humidity, temperature, exposure, and karma all have an effect. Nonetheless, the table provides some guidance. As another general guideline, bandwidth is affected by water concentration. Narrow band results are produced in the 150-250 range (meaning a 10-30-200 DCG formula, for example), and broader-band playback from the 300-350 range. 0039f013bc6d1759a0ba34bd8b8e10ad89c986b4 2198 2197 2013-11-29T04:43:39Z Jsfisher 1 wikitext text/x-wiki Danny Bruza [http://holoforum.org/oldforum/viewtopic.php?f=13&t=2995] was kind enough to share this chart he had made for his own use. The chart gives the playback Danny gets for a sequence of dichromate-to-gelatin concentrations at each of three recording wavelengths, 532nm, 514nm, and 405nm. {| class="wikitable" border="1" |- ! Di-gel ! 532nm ! 514nm ! 405nm |- | 10-30 || 532 || 514 || 405 |- | 09-30 || 552 || 533 || 424 |- | 08-30 || 571 || 552 || 443 |- | 07-30 || 590 || 571 || 462 |- | 06-30 || 609 || 590 || 481 |- | 05-30 || 628 || 609 || 500 |- | 04-30 || 647 || 628 || 519 |- | 03-30 || 666 || 647 || 538 |- | 02-30 || 685 || 666 || 557 |- | 01-30 || 704 || 685 || 576 |} Results can vary. Many, many factors come into play with dichromated gelatin. Gelatin bloom strength, humidity, temperature, exposure, and karma all have an effect. Nonetheless, the table provides some guidance. As another general guideline, bandwidth is affected by water concentration. Narrow band results are produced in the 150-250 range (meaning a 10-30-200 DCG formula, for example), and broader-band playback from the 300-350 range. 4d9cc1f56f6b56539e3e8db262aba9ab1d0c1978 6 946 2201 2014-01-01T02:42:10Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 947 2202 2014-01-01T02:42:13Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 948 2203 2014-01-01T03:01:49Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 949 2204 2014-01-01T03:01:52Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 950 2205 2014-01-01T03:01:53Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 951 2206 2014-01-01T03:02:13Z Jsfisher 1 Created page with "The film holder for these exposures is a magazine that was designed to fit on the back of a Long Roll Camera. A typical Long Roll Camera's job would be when photographers wou..." wikitext text/x-wiki The film holder for these exposures is a magazine that was designed to fit on the back of a Long Roll Camera. A typical Long Roll Camera's job would be when photographers would come into a school and take pictures of everyone. This back was made by Beattie-Coleman. I purchased it from Helix Camera around 1984. My friend Tom Kovarik, electronics technician at FermiLab, built a control box for it which powers up the unit with 120 VAC by way of an on-off toggle switch and equipped with a momentary push-button switch to advance the film for me. I later added a solid-state switch to the control box when I automated the advance trigger. The lovely crackled black finish got removed at the same time that some rust was removed! What a shame! [[Image:70mmLid.jpg|400px|Beattie-Coleman 70 mm back used for holography]] An AC motor drives the take up spool on the left to shuttle the film from the supply spool on the right. One complete revolution of the roller on the left moves the film one full frame by a cam pushing a micro-switch under the base plate. A pressure plate pushes the film forward into the open aperture. It is surprising that the film is stable enough during exposures as it is held only by the edges! [[Image:70mmInside.jpg|400px|The guts of a 70mm Beattie-Coleman back used for holography]] The back's dark slide is in position, so that the transport loaded with film can be positioned with the room lights on. A piece of cardboard with centering marks helps to position the transport in the proper place, or to align the beams to the back. [[Image:70mmBackFront.jpg|400px|The front of the 70mm Beattie-Coleman back used in a holographic set up]] There is a counter on the side of the transport to check how many were shot or how much is left on the roll.  It is the dark rectangle on the lower front of the unit, unfortunately this photo does not show the numbers. There are about 300 frames on a 100 foot roll of film. Here is a view of the various control devices on their cart. At the top left is the el-don (nee Jodon, that's a sticker THE Don Gillespie put on the box when refurbishing it) driver for the Scanning Fabry-Perot Spectrum Analyzer; under it is the Uniblitz Shutter Controller Driver; the old school closed circuit black and white monitor shows what its attached camera is pointed at, in this case the alignment card in the 70mm back. The remote controls for the HVAC and tunes are watching the TV. The storage oscilloscope on the right monitors exposure time, and under it is the controller to power up and advance the film back. [[Image:ControllCart.jpg|400px|From the lab of a Mad Holographic Scientist]] When in run mode, the Uniblitz shutter driver makes the exposure, then when the exposure is terminated, the shutter driver sends a signal to the controller made on a Radio Shack Electronics Lab breadboard (that I had bought for my sons many Xmasses ago) which then holds in the solid state relay in the back's control box to get the transport started moving the film, which will stop on its own after one frame is advanced. The breadboard controller waits for the appropriate settling time, then sends a signal to the Uniblitz controller which makes an exposure, and starts the series over again. With a 50 second settling time and a fraction of a second exposure time, that translates to approximately 5 hours to run through the whole 100 foot roll. [[Image:ControlCart2.jpg|400px|DIY electronics for the 70mm back]] If anyone in the group is interested in making a run of holograms in this format, please contact me. 6d2ec016501ee05f2b762e3d794e5a9f75468219 0 952 2207 2014-01-01T03:06:49Z Jsfisher 1 Created page with "The following pages were derived from Ed Wesly's web pages at http://nlutie.net/ewesly. * [[Ewesly / 70 mm Film Transport | The 70 mm file transport]]" wikitext text/x-wiki The following pages were derived from Ed Wesly's web pages at http://nlutie.net/ewesly. * [[Ewesly / 70 mm Film Transport | The 70 mm file transport]] 2a20543009cbb69db3b3a744408ba67569802a67 2209 2207 2014-01-01T03:21:24Z Jsfisher 1 wikitext text/x-wiki The following pages were derived from Ed Wesly's web pages at http://nlutie.net/ewesly. * [[Ewesly / 70 mm Film Transport | The 70 mm file transport]] {| |- | * [[Ewesly / Holographic Pedagogy | Holographic Pedagogy]] * [[Ewesly / Holographic R&D | Holographic R&D]] * [[Ewesly / Holographic Artwork | Holographic Artwork]] * [[Ewesly / Holographic Formulae | Holographic Formulae]] * [[Ewesly / Publications | Publications]] * [[Ewesly / The New Adventures of Hans and Ed | The NEW Adventures of Hans and Ed]] | [[Image:WinterWonderlandCsm.jpg|right]] |} 07db64b3211e1a7f33cb3119e40468c573f003e1 2210 2209 2014-01-01T03:22:06Z Jsfisher 1 wikitext text/x-wiki The following pages were derived from Ed Wesly's web pages at http://nlutie.net/ewesly. = Hologrammy = {| |- | * [[Ewesly / Holographic Pedagogy | Holographic Pedagogy]] * [[Ewesly / Holographic R&D | Holographic R&D]] * [[Ewesly / Holographic Artwork | Holographic Artwork]] * [[Ewesly / Holographic Formulae | Holographic Formulae]] * [[Ewesly / Publications | Publications]] * [[Ewesly / The New Adventures of Hans and Ed | The NEW Adventures of Hans and Ed]] | [[Image:WinterWonderlandCsm.jpg|right]] |} f36a6f06e3ba3b830e57a59d08592a542c6a5219 6 953 2208 2014-01-01T03:13:30Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 954 2211 2014-01-01T03:30:54Z Jsfisher 1 Created page with "Here are a variety of Lessons that I have developed over my decades of teaching the subject of Holography. Hopefully they might prove useful to someone! '''Warning!''' If I ..." wikitext text/x-wiki Here are a variety of Lessons that I have developed over my decades of teaching the subject of Holography. Hopefully they might prove useful to someone! '''Warning!''' If I ever find someone who is using this material for commercial profit, like turning it into a book, I will gladly hunt them down and show them what's good for them! Otherwise, fellow holographic educators, feel free to use any and all for classroom handouts. * [[Ewesly / Making a test strip | Making a test strip]] * [[Ewesly / Seven single beam projects | Seven single beam projects]] * [[Ewesly / Instruction manual for Room B013 | Instruction manual for Room B013]] * [[Ewesly / Gallery 1134 classes: Holo I and II handouts | Gallery 1134 classes: Holo I and I handouts]] * [[Ewesly / Projects in Holography | Projects in Holography]] aa619583174c927bd92fe2571251133f8ff28111 0 955 2212 2014-01-01T03:41:08Z Jsfisher 1 Created page with "== Preamble == This section of the Web Site is the Benchmark Project for the TIE 594 Web Process in Education class that I have taken at National-Louis University, and as such..." wikitext text/x-wiki == Preamble == This section of the Web Site is the Benchmark Project for the TIE 594 Web Process in Education class that I have taken at National-Louis University, and as such is written with an educator's overview. Big shout out for NLU to host this site (at least until I get my degree!) and to Dr. Craig Cunningham who has been so very patient with me! There is a decided lack of how exactly to run these simple holographic recording materials calibration tests in textbooks and on the web, so I decided it’s high time to demonstrate this all-important aspect of the holographic recording process. == Introduction == # This lesson’s subject matter is the methodology of peaking getting the best (brightest or most easily viewed) hologram on commercially available films and plates. # Students will learn the importance of exposure by making a test strip and the importance of development time, plus the role and interesting results obtainable by two different types of processing chemistries. This curriculum is centered on controlling the variables of the holographic recording film’s processing procedure, and how to troubleshoot processing errors. This entails varying the following parameters and analyzing the results. Exposure as a function of intensity and time * exposure test series * role of the developer * developing time variations * different types of developers * the role of the bleach * different types of bleach. At the end of this unit, the student holographer will be able to: * Make a test strip of a sensible order of exposures * Choose the developer and bleach combination that will give the final desired color * Follow the timing of the processing steps * Troubleshoot exposure and processing errors Once you are committed to becoming a holographer, you admit that you are a laser nerd and want to soak up all the possible information about the process, so there would be a very positive mental attitude carried into this lesson. The information might be totally brand new to some, and would be even better appreciated by those who have had some success and failures, as they may have not approached the problem in a systematic way. Since the whole process is extremely technical and there was some capital outlay for the equipment and film, there would perforce be a very positive mental attitude, especially if the holographer has a certain goal in mind for the finished piece. The point of this exercise is to show how to tune in the exposure and processing aspects of recording a hologram. The directions included with the film (when they are included) are oftentimes erroneous, behind the times, irrelevant, etc.By playing with the parameters, the students should learn the methodology and apply it to the holographic films currently available or those that may appear in the future. The holographer needs to know the dynamic range of the material if it is foreseen to do multiple exposures for color blending or double exposed interferometry. Once a system is tuned in with exposure parameters constant any object can be placed in position and the same exposure and development can be used to give optimal results. The brightness of the final holograms would be affected by the relative reflectivity of the objects, stronger reflectors giving brighter holograms, and weaker objects could be compensated for by bumping up the exposure time. The Single Beam Reflection Hologram recording scheme was chosen for this tutorial as it \is very popular in introductory holography classes with its immediate gratification of a hologram that doesn’t need a laser to be viewed. It is also quick to set up as there is no need for beamsplitting, only beamspreading. With a split beam set up there is more versatility as far as objects, beam balance ratio, etc., goes, however there are more parameters to keep under strict control and more optics to keep still during exposure. With a solid object that has kinematic positioning, like the Standard Holographic Object waffle iron, object movement is not an issue. This SBR set up (often known as the Denisyuk scheme, after the Russian Holographic Deity, Yuri Denisyuk), puts high resolution demands on the recording material, with its fringe spacing on the scale of a half a wavelength of the recording laser color, so it is a good test to see how good the material really is. Not all holographic films and plates are capable of recording this type of hologram well or even at all! For the sake of this lesson, it is assumed that the student has the necessary prerequisites. == Prerequisites == For this lesson, it is assumed that the student probably has heard the basic raps on the theory of holography and how it’s different from photography has followed directions either from this site or some other source and has the necessary equipment (laser, beamspreader, isolation table, object, holographic film and chemistry) to set up the necessary optical configuration to record a hologram, (preferably the type known as Single Beam Reflection) (the Googling is left up to the reader, start with Single Beam Reflection Hologram or Denisyuk hologram) and is ready to load the holographic film into the set up. By the time the student holographer is ready to make an exposure, they will have built the optical configuration. It is probably unlikely that they have worked in a photographic darkroom, which is the void that this unit will try to fill. Unless the students have no interest in the process and have been coerced into the lab, they will have a positive mental attitude toward the whole thing, and the only danger is that they might be so over-enthusiastic that they might not want to go through the discipline of a systematic shakedown of the exposure and development process. But even if their exuberance overpowers common sense, they will come back to this lesson when they want to make the best possible result. 68176c83b2337d7efb826329a591c914ae89b001 2213 2212 2014-01-01T03:42:00Z Jsfisher 1 /* Introduction */ wikitext text/x-wiki == Preamble == This section of the Web Site is the Benchmark Project for the TIE 594 Web Process in Education class that I have taken at National-Louis University, and as such is written with an educator's overview. Big shout out for NLU to host this site (at least until I get my degree!) and to Dr. Craig Cunningham who has been so very patient with me! There is a decided lack of how exactly to run these simple holographic recording materials calibration tests in textbooks and on the web, so I decided it’s high time to demonstrate this all-important aspect of the holographic recording process. == Introduction == # This lesson’s subject matter is the methodology of peaking getting the best (brightest or most easily viewed) hologram on commercially available films and plates. # Students will learn the importance of exposure by making a test strip and the importance of development time, plus the role and interesting results obtainable by two different types of processing chemistries. This curriculum is centered on controlling the variables of the holographic recording film’s processing procedure, and how to troubleshoot processing errors. This entails varying the following parameters and analyzing the results. Exposure as a function of intensity and time * exposure test series * role of the developer * developing time variations * different types of developers * the role of the bleach * different types of bleach. At the end of this unit, the student holographer will be able to: * Make a test strip of a sensible order of exposures * Choose the developer and bleach combination that will give the final desired color * Follow the timing of the processing steps * Troubleshoot exposure and processing errors Once you are committed to becoming a holographer, you admit that you are a laser nerd and want to soak up all the possible information about the process, so there would be a very positive mental attitude carried into this lesson. The information might be totally brand new to some, and would be even better appreciated by those who have had some success and failures, as they may have not approached the problem in a systematic way. Since the whole process is extremely technical and there was some capital outlay for the equipment and film, there would perforce be a very positive mental attitude, especially if the holographer has a certain goal in mind for the finished piece. The point of this exercise is to show how to tune in the exposure and processing aspects of recording a hologram. The directions included with the film (when they are included) are oftentimes erroneous, behind the times, irrelevant, etc.By playing with the parameters, the students should learn the methodology and apply it to the holographic films currently available or those that may appear in the future. The holographer needs to know the dynamic range of the material if it is foreseen to do multiple exposures for color blending or double exposed interferometry. Once a system is tuned in with exposure parameters constant any object can be placed in position and the same exposure and development can be used to give optimal results. The brightness of the final holograms would be affected by the relative reflectivity of the objects, stronger reflectors giving brighter holograms, and weaker objects could be compensated for by bumping up the exposure time. The Single Beam Reflection Hologram recording scheme was chosen for this tutorial as it \is very popular in introductory holography classes with its immediate gratification of a hologram that doesn’t need a laser to be viewed. It is also quick to set up as there is no need for beamsplitting, only beamspreading. With a split beam set up there is more versatility as far as objects, beam balance ratio, etc., goes, however there are more parameters to keep under strict control and more optics to keep still during exposure. With a solid object that has kinematic positioning, like the Standard Holographic Object waffle iron, object movement is not an issue. This SBR set up (often known as the Denisyuk scheme, after the Russian Holographic Deity, Yuri Denisyuk), puts high resolution demands on the recording material, with its fringe spacing on the scale of a half a wavelength of the recording laser color, so it is a good test to see how good the material really is. Not all holographic films and plates are capable of recording this type of hologram well or even at all! For the sake of this lesson, it is assumed that the student has the necessary prerequisites. == Prerequisites == For this lesson, it is assumed that the student probably has heard the basic raps on the theory of holography and how it’s different from photography has followed directions either from this site or some other source and has the necessary equipment (laser, beamspreader, isolation table, object, holographic film and chemistry) to set up the necessary optical configuration to record a hologram, (preferably the type known as Single Beam Reflection) (the Googling is left up to the reader, start with Single Beam Reflection Hologram or Denisyuk hologram) and is ready to load the holographic film into the set up. By the time the student holographer is ready to make an exposure, they will have built the optical configuration. It is probably unlikely that they have worked in a photographic darkroom, which is the void that this unit will try to fill. Unless the students have no interest in the process and have been coerced into the lab, they will have a positive mental attitude toward the whole thing, and the only danger is that they might be so over-enthusiastic that they might not want to go through the discipline of a systematic shakedown of the exposure and development process. But even if their exuberance overpowers common sense, they will come back to this lesson when they want to make the best possible result. 26cf997cf03c7c8da74ca4b11c47ea185e08fc52 6 956 2214 2014-01-01T03:53:02Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 957 2215 2014-01-01T03:53:03Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 958 2216 2014-01-01T03:53:04Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 959 2217 2014-01-01T03:53:06Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 960 2218 2014-01-01T03:53:08Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 961 2219 2014-01-01T03:53:09Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 962 2220 2014-01-01T03:58:44Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 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2014-01-01T04:09:14Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1018 2277 2014-01-01T04:09:17Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1019 2278 2014-01-01T04:09:19Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1020 2279 2014-01-01T04:09:21Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1021 2280 2014-01-01T04:09:23Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1022 2281 2014-01-01T04:09:26Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1023 2282 2014-01-01T04:09:28Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 955 2283 2213 2014-01-01T04:27:41Z Jsfisher 1 wikitext text/x-wiki == Preamble == This section of the Web Site is the Benchmark Project for the TIE 594 Web Process in Education class that I have taken at National-Louis University, and as such is written with an educator's overview. Big shout out for NLU to host this site (at least until I get my degree!) and to Dr. Craig Cunningham who has been so very patient with me! There is a decided lack of how exactly to run these simple holographic recording materials calibration tests in textbooks and on the web, so I decided it’s high time to demonstrate this all-important aspect of the holographic recording process. == Introduction == # This lesson’s subject matter is the methodology of peaking getting the best (brightest or most easily viewed) hologram on commercially available films and plates. # Students will learn the importance of exposure by making a test strip and the importance of development time, plus the role and interesting results obtainable by two different types of processing chemistries. This curriculum is centered on controlling the variables of the holographic recording film’s processing procedure, and how to troubleshoot processing errors. This entails varying the following parameters and analyzing the results. Exposure as a function of intensity and time * exposure test series * role of the developer * developing time variations * different types of developers * the role of the bleach * different types of bleach. At the end of this unit, the student holographer will be able to: * Make a test strip of a sensible order of exposures * Choose the developer and bleach combination that will give the final desired color * Follow the timing of the processing steps * Troubleshoot exposure and processing errors Once you are committed to becoming a holographer, you admit that you are a laser nerd and want to soak up all the possible information about the process, so there would be a very positive mental attitude carried into this lesson. The information might be totally brand new to some, and would be even better appreciated by those who have had some success and failures, as they may have not approached the problem in a systematic way. Since the whole process is extremely technical and there was some capital outlay for the equipment and film, there would perforce be a very positive mental attitude, especially if the holographer has a certain goal in mind for the finished piece. The point of this exercise is to show how to tune in the exposure and processing aspects of recording a hologram. The directions included with the film (when they are included) are oftentimes erroneous, behind the times, irrelevant, etc.By playing with the parameters, the students should learn the methodology and apply it to the holographic films currently available or those that may appear in the future. The holographer needs to know the dynamic range of the material if it is foreseen to do multiple exposures for color blending or double exposed interferometry. Once a system is tuned in with exposure parameters constant any object can be placed in position and the same exposure and development can be used to give optimal results. The brightness of the final holograms would be affected by the relative reflectivity of the objects, stronger reflectors giving brighter holograms, and weaker objects could be compensated for by bumping up the exposure time. The Single Beam Reflection Hologram recording scheme was chosen for this tutorial as it \is very popular in introductory holography classes with its immediate gratification of a hologram that doesn’t need a laser to be viewed. It is also quick to set up as there is no need for beamsplitting, only beamspreading. With a split beam set up there is more versatility as far as objects, beam balance ratio, etc., goes, however there are more parameters to keep under strict control and more optics to keep still during exposure. With a solid object that has kinematic positioning, like the Standard Holographic Object waffle iron, object movement is not an issue. This SBR set up (often known as the Denisyuk scheme, after the Russian Holographic Deity, Yuri Denisyuk), puts high resolution demands on the recording material, with its fringe spacing on the scale of a half a wavelength of the recording laser color, so it is a good test to see how good the material really is. Not all holographic films and plates are capable of recording this type of hologram well or even at all! For the sake of this lesson, it is assumed that the student has the necessary prerequisites. == Prerequisites == For this lesson, it is assumed that the student probably has heard the basic raps on the theory of holography and how it’s different from photography has followed directions either from this site or some other source and has the necessary equipment (laser, beamspreader, isolation table, object, holographic film and chemistry) to set up the necessary optical configuration to record a hologram, (preferably the type known as Single Beam Reflection) (the Googling is left up to the reader, start with Single Beam Reflection Hologram or Denisyuk hologram) and is ready to load the holographic film into the set up. By the time the student holographer is ready to make an exposure, they will have built the optical configuration. It is probably unlikely that they have worked in a photographic darkroom, which is the void that this unit will try to fill. Unless the students have no interest in the process and have been coerced into the lab, they will have a positive mental attitude toward the whole thing, and the only danger is that they might be so over-enthusiastic that they might not want to go through the discipline of a systematic shakedown of the exposure and development process. But even if their exuberance overpowers common sense, they will come back to this lesson when they want to make the best possible result. == The Standard Object == For researching holographic recording materials I have a '''Standard Single Beam Reflection Test Object''', a silver spray painted waffle iron mold.&nbsp; This object presents a not very deep texture which is homogenous throughout the exposure test quadrants.&nbsp; Plus it's fun to look at the <u>pseudoscopic side</u> because it looks like the waffle.&nbsp; The holographic plate sits on three ball bearings glued onto the waffle iron. A bar prevents it from sliding down and blocks light from entering the edge of the plate, which could result in colored bands of internal reflections along the top edge of the plate. [[Image:kinematic.jpg]] The iron mold is supported in a kind of goal post arrangement so that it can be tilted to give a decent reference angle, which was about 30 degrees from the normal in this case to prevent the shadows of the waffle texture from getting too long.&nbsp; A support from the bottom prevents it from falling/rotating during exposure. Notice that in this configuration the holographic recording is upside down from the holographic replay. The figure below shows the rig with a plate processed to replay laser red replaced back into its exposed position and illuminated with the laser, generating real-time interferometric fringes, demonstrating the stability of the kinematic device. The reflections on the ball bearings aid the repositioning. Give it a try, it's not that difficult! [[Image:SBRFringes.jpg]] Maybe every holographer could make their own waffle iron test object similar to this one so that at future symposia of display holography everyone could whip out their holo-waffles to really see whose films and processing really are the best.&nbsp; The waffle is a universal breakfast food, so that everyone in the Global Coterie of Holography could find one to use in a thrift shop. Not only is good coherence important for generating strong interference fringes, but the two interfering beams should have their polarizations vectors aligned.&nbsp; Most of the objects doomed to be holographed are diffuse reflectors, but who says that diffusely reflecting objects can’t preserve polarization? [[Image:PolaPaint_0000_Layer 1.jpg]] [[Image:PolaPaint_0001_Background.jpg]] A polarized Helium-Neon laser illuminates the '''Standard Single Beam Reflection Test Object''' which is photographed through a polarizing filter aligned to pass vertical polarization vectors. The polarizing filter is rotated 90 degrees, and the diffusely reflecting white painted Target Card photographs well, since diffuse reflectors scramble the polarization vectors, but the Test Object dims out, since its reflection is polarized orthogonally! The secret to the polarization preserving object is the paint; Krylon #1401 Bright Silver and others of this ilk use tiny aluminum flakes as the “pigment”, and being metallic, they are specular reflectors which preserve polarization.&nbsp; The flakes are so tiny that their orientation preserves polarization while conforming to the diffusely reflecting surface underneath.&nbsp; Be aware that some brands of paint dry more specular, looking like polished chrome, which doesn’t look that good for this purpose. Those who are more advanced might enjoy this: He-Ne red and Frequency-doubled YAG green beams were made collinear using a polarization preserving broadband beamsplitting/combining cube.&nbsp; This results in the two beams being polarized at right angles to each other, and in this case the red beam is (p) polarized which turns out to be horizontal, and the green’s (s) polarization is vertical. [[Image:PolaBeams.jpg]] The left image shows a predominantly green beam with some yellow and orange undertones since both red and green beams are present. A Polaroid filter is in front of the camera set to pass horizontal polarization in the middle image, where the red beam shows through while the green is blocked. Rotating the Polaroid 90 degrees results in the vice versa at the end, green pass and red blocked. The diffusely reflecting paper in the background is visible as more or less yellow in both polarization orientations since the paper’s diffuse reflection scrambles the polarization vectors. [[Image:Polar3Up.jpg]] == Exposure == Is defined as a function of Intensity and Time: E = I * t. Every light-sensitive material requires a certain quantity of exposure to do its job properly. The classical photographic analogy is to compare exposure of film (or an electronic sensor, more than likely in this era) to filling a glass with water. A trickle of water coming out of the faucet will take a long time to fill the glass while a wide-open torrent will take a short time. On a camera, the faucet is replaced by the iris, f/stop, aperture, diaphragm, whatever you want to call it, which limits the flow of light through the lens, while the shutter controls the length of time of photon delivery. To go one step further, the sensitivity of the film, the ISO speed rating, can be modeled by the volume of the cup; high sensitivity, requiring less light to do its job, would be represented by a smaller cup, while a less sensitive film with a lower ISO would be represented by a larger cup to be filled. For a holographic model of exposure, the flow of water would be represented by the power of the laser; little He-Ne’s and pointers would be like garden hoses, and fire-breathing Argons and YAG’s would be like fire truck hoses. The sensitivity of the holographic recording material would be represented by the height of the receptacle, while the spread of the laser beam would determine the diameter of the receptacle. A beaker a decimeter tall and a decimeter in diameter could represent the photon thirst of a holographic plate that’s of the convenient 6 by 6 cm (2 ½”) size; along the same lines, a container that is 6 decimeter in diameter that is filled to a depth of one decimeter is the volume of photonic liquid that is needed for a 30 by 40 cm plate. Even a small flow would take a reasonable amount of time to fill the former; the latter, a pretty long time. '''Scroll down if this spiel becomes overwhelming.''' When calculating exposure in holography, the amount of light available per unit area comes into play, the unit standardized upon being “per square centimeter”. Lasers’ output powers, being sources of light, are typically measured in Watts or fractions thereof. A reading of light power delivered to the holographic recording plate is generally described in microwatts per square centimeter, muW/cm2 for short, and if you’re dangerously lucky you could be measuring milliwatts per square centimeter, mW/cm2, for the fire hoses of the high power lasers. (It seems like html doesn't support the metric symbol for micro, the Greek letter mu, so I am inserting mu for the abbreviation. When it's mJ it's milliJoules. Plus the superscript 2 is coming out as a plain old 2 in the abbreviated centimeter squared. Sorry!) What’s in a Watt? A Watt is a measure of power; a force that is delivered constantly as long as the source is turned on. Intensity in other words. But exposure integrates intensity during a length of time, which physicists define as energy, so another physics unit, the Joule, is used to define exposure doses. A Joule is a measure of energy; how much power is delivered during a period of time. A Joule is defined as a Watt – second; a 1 Watt light bulb turned on for one second emits a Joule of energy. Notice that a Joule is not a Watt per second which means divided by seconds, but multiplied by seconds. The units for exposure doses for holographic recording materials are microJoules per square centimeter, muJ/cm2, ranging from tens of them for the old high speed materials like Agfa 10E75 and Kodak SO-253 to hundreds for Agfa 8E75HD and Slavich PFG-01 to thousands for Slavich PFG-03M and Sphere-S GEO-3, plus photo-resists and dichromated gelatins, or more properly milliJoules per square centimeter, mJ/cm2, since there are a 1,000 micros in a milli. Calculating exposure times can be based on knowing how many muJ/cm2 are required from the manufacturer’s instructions, measuring the power of the light per unit area at the film plane in mW/cm2, and dividing the energy reading into the power requirement to get the exposure time. Example: A holographic film allegedly requires 200 mJ/cm2 to do its job. 50 mW/cm2 is measured at the film plane. 200 divided by 50 = 4, so a 4 second exposure would be required. '''Stop scrolling here for the bottom line!''' But not everyone has a laser power meter, nor does one trust their power meter if they do have one, or trust the manufacturer’s energy requirements. An exposure test series, similar to what photographers would do in making a print in the darkroom needs to be made to fine tune the exposure to get the optimum result. The intensity part of the exposure is determined by how much the given laser beam’s power is spread over the area to be holographed; the holographer finds the appropriate time at first by trial and error, but then can calibrate their own exposure dosages. == Intensity == In photography, the light from the source arrives at a scene, whose reflectance the intensity of the light reflected from the scene is further controlled by the aperture of the lens. In holography, the laser’s light bathes the object and that light arrives at the holographic plate without a lens in the way. The intensity of the light bathing the object is determined by how wide the laser beam is spread, which determines the exposure time. The raw laser beam is centered on the target card, which could be a dud holographic plate painted white with cross hair fiducial marks on it, or a similarly sized piece of cardboard. [[Image:AlignmentDot.jpg|center]] Here the beam is diverged only slightly, not even totally filling up the image space, which would result in a hologram whose brightness would vary from the center outward, or even a color variation radially with some processing schemes. [[Image:CoverageUnder.jpg|center]] The beam is spread big enough to more than cover the <strong>Standardized Test Object</strong>, just in case the testing finds a very kick ass bright exposure and development times combination and the spirit moves one to holograph the whole thing!</p> [[Image:CoverageCorrect.jpg|center]] For consistent results the intensity should be measured, ideally with a calibrated light meter, and recorded in the Log Book. For those not so fortunate, consistent results could also be achieved by using a selenium, CdS, or silicon cell attached to a VOM to measure intensity. If this same radiant flux is acheived again, exposure time should be the same, leaving the processing schedule at the status quo. If half the light is detected, then the exposure time needs to be doubled; if twice the light is detected, then the time needs to be halved, and so forth. == Shutters == An accurate and repeatable shuttering system is very helpful with these tests to initiate and terminate the exposures.&nbsp; The old fashioned way dating back to the ancient daguerreotypists (who simply removed and replaced a lens cap to fulfill their exposure obligations) would be to lift a card out of the path of the laser beam, with an eye on the clock.&nbsp; For the typical holographic exposures of multiples of seconds, a clock with a second hand or a stop watch is sufficient.&nbsp; Picking the beam blocker up off vibration isolation device before yanking it out of the beam’s path avoids vibrations being translated to the working surface, or better yet, having it located off the table, but nevertheless in the beam path. [[Image:ManualShutter.gif]] The pulling out of the beam blocker may become tiring with attendant inaccuracies, so automated mechanisms would be more productively employed. An electronic device called a solenoid, the devices that give the “clunk” of electrical car locks, can pull a cardboard beam locker out of the way.&nbsp; They can be powered by the appropriate voltage of wall wart.&nbsp; The switch on a power strip can turn it on or off instead of pulling it out of the wall, again manually timed. The most exquisitely quiet shutter I had ever seen was devised by the late great Rudie Berkhout who used a d’Arsonval movement from a classic VOM, so that when voltage was applied the meter pointer moved a flag out of the beam path. [[Image:Shutter.gif]] What would be the deluxe set up with one of these would be to have it electronically timed, using a darkroom timer, either of the enlarging type with durations of one-tenth of a second and upwards, or the classic backward running darkroom clock, a Gra-Lab Universal Timer.&nbsp; With so many chemical photographers getting out of the game, these timekeepers might be easily picked up at garage sales, etc.&nbsp; A timer hacked out of a http://nutsvolts.texterity.com/nutsvolts/200906?pg=44&search_term=darkroom%20timer%20microwave%20oven#pg44 has even been implemented. [[Image:DarkroomTimer copy.jpg]] [[Image:GraLab.jpg]] <p>For fraction of a second timing (if you have that powerful of a laser!) an old-school SLR film camera can be placed in the beampath, with the back open and the lens taken off.&nbsp; Older mechanical cameras offer only the option of binary fractions, starting at 1 second, then ½, ¼, 1/8, 1/15 (instead of 1/16 since everyone likes number that end in 5’s or 0’s), 1/30, 1/60, 1/125, etc.&nbsp; CAUTION! Higher power laser beams might burn holes in the black coatings of the focal plane shutters.<br /> </p> [[Image:NikonShutter.gif]] <p>Between the lens shutters could also be used, but with the lenses removed.&nbsp; The glass could be used as a beam spreader, but if they were left on the shutter housing there is the risk of the beam moving as the shutter is tripped.&nbsp; Cable releases will minimize the vibration transference.&nbsp; If salvaged off of older cameras, the times may not be of a binary type of timing.<br /> </p> [[Image:Ilex.jpg]] <p>Of course, there are professional grade shutters, with aluminized blades for holding off high power lasers, like this one, which can time both exposure <u>and</u> setting time.&nbsp; I got this one for a song and a dance.&nbsp; (Eat your hearts out!&nbsp; Then again, how often do I use a millisecond?)</p> [[Image:UniblitzInAction.gif]] <p>And if you really want to be jealous, dig this sweet set up: the UniBlitz shutter initiates the exposure, the Newport Power Meter's sensor sends a signal to the mighty Kikusui Storage Oscilloscope, and the exposure intensity and time are displayed on the 'scope's screen!</p> [[Image:NewpScopeCrop.jpg]] <p>Here are the 4 positions of the test card at work. Remember to let the apparatus settle between each exposure.</p> [[Image:4PositionsAnimTitles.gif]] <p align="left">An exponentially increasing series of exposure times is preferred as evidenced in the animation above.&nbsp; This is because the eye sees logarithmically; it looks for ratios between values, not absolute intensity.&nbsp; Notice the rhythm of the grey scale below; each step is twice or half as bright as the one next to it.</p> [[Image:GreyScaleLin.jpg]] <p>Photographers call this type of sequence the series of stops, based on 2 to the nth power, n being an integer.&nbsp; (Don’t forget, integers include zero and negative numbers, with 2 to the zero power = 1, and 2 to the negative first power = 1 over 2 to the first power or ½, 2 to the negative second power = 1 over 2 to the second power or 1/4, etc.)</p> <p>For greater precision, use half stops.&nbsp; But the series doesn’t become 1, 1.5, 2, 3, but as bunch of numbers familiar to photographers as the f/numbers: 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 45, 64…&nbsp; Every <u>other</u> number is doubled or halved depending on which direction you are going, and its root is the square root of two raised to an integral power! Here is an exposure series run in this manner.</p> [[Image:CWC2D4TS.jpg]] <p>Rotary motion of the blocking card is the best configuration to ensure that all test sections have similar intensities and not bias the results with uneven beam spreads.&nbsp; If a blocker were moved laterally, the edge exposures would not see the same amounts of light as the center strips illustrated below because of the radial intensity gradient caused by the Gaussian distribution of the laser beam’s power.</p> [[Image:UnderCoverageStrips2.jpg]] == Processing == <p>There are so many recipes out there it is beyond the scope of this part of the exercise to enumerate them all.&nbsp; But some general recommendations follow.<br /> </p> <p>The JD-3 and JD-4 kits sold by [http://www.holokits.com/ Integraf] [http://stores.photoformulary.com/StoreFront.bok Photographers’ Formulary] would be good starting points for this exercise, as when properly done the final results will provide a reflection hologram that replays in the same color as the laser that recorded it.&nbsp; This helps in the Assessment stage.<br /> </p> <p>Development: Keeping development temperature constant will help ensure consistent results from session to session.&nbsp; The extremely fine-grained Russian emulsions, Slavich PFG-03 and Sphere-S GEO-03, benefit from 15 degrees Centigrade (65 degrees Fahrenheit) developer temperatures!&nbsp; Constant agitation is also important!&nbsp; And timing is key!&nbsp; Pick a time and stick to it!&nbsp; Vary the exposure time to control how dark the hologram develops and ultimately how bright it gets.&nbsp; What is the correct development time?&nbsp; Make several plates of exposure series and develop them for different times, and see which looks the best!<br /> </p> <p>Rinsing: By getting the developer out of the emulsion before the next bath, this rinse is key to longevity of the bleach and cleanliness of the final hologram. At least a minute with running water, preferably 2 - 3 minutes.<br /> </p> <p>Bleaching: This isn’t like laundry bleach, but a processing step which ultimately makes the hologram brighter.&nbsp; Agitation is not as critical as in development, but moving the plate around to freshen up the chemistry in the coating as it gets used up is a good idea.<br /> </p> <p>Rinsing Again: To get the bleach out of the emulsion.&nbsp; Sometimes the bleach leaves a color cast in the emulsion, once that disappears then the chemistry is completely removed, let it rinse another minute or so, then use the <br /> </p> <p>Wetting Agent: which is a surfactant that lets the liquids sheet out of the light sensitive coating and prevents streaking, not unlike the final rinse in a dishwasher.</p> I personally do not use nor recommend squeegees or hair dryers to speed up drying times, having witnessed way too many disasters. == Assessment == <p>How does the holographer determine if the optimal exposure is found?&nbsp; What are we looking for?&nbsp; For this exercise it is assumed the neophyte holographer is using the prepackaged chemistry kits from [http://www.holokits.com/" Integraf] or [http://stores.photoformulary.com/StoreFront.bok Photographers’ Formulary] called JD-3 or JD-4, as when processed properly the color of a SBR is the same as the laser color, which can aid in the evaluation of the exposure. These kits employ development followed by a rehalogenating bleach, which preserve the dimensions of the recorded interference fringes. (For more details, see CWC2.) Using JD-1 or JD-2 where the processing results in a color shifted image gets more complicated, because a green image appears brighter to the eye than does a red, even though radiometrically (absolute energy measurement) the red might weigh in brighter!&nbsp; Plus there are other interesting tricks than can be done if the color is not shifted! In the figure below the reflection hologram is illuminated by a laser during reconstruction, and the hologram &quot;steals&quot; the light and transforms it into an image wavefront, depleting the straight through beam and casting a shadow. The darkest shadow shows the greatest efficiency or brightness.</p> [[Image:ShadowAssess.jpg]] <p align="left">Here the hologram is held in front of the object, with an alignment card in place of a plate on the object. The image is apparent in the hologram since it is held at the appropriate reconstruction angle. Where there was no exposure, the blank areas in the test strip, looking dark in the holo, is where the maximum amount of light passes through the devloped plate, making the bright cross on the target card. In this orientation, the minimal exposure is in the lower left, and its shadow is the weakest, showing the minimal amount of diffraction efficiency, although still a healthy amount. The exposures increase CW from there, and you can see that less than half the light passes through the maximum exposure step, meaning that more than half the light is turned into image light! This was a BB-520 plate from HRT of Germany, (now Colour Holographics of England), developed in BBAA and bleached in a FeEDTA solution. Exposure doses were 400, 800, 1600 and 3200 microJoules per square centimeter. CAUTION! Some holographic materials cast deeper shadows not because of high efficiency but because of &quot;noise&quot;, a cloudy haze precipitated by scatter from relatively large grain sizes.</p> <p align="left">A quicker variation of the above scheme is to replace the plate on the object slightly displaced. Here you can see the image is brighter than the object in a couple of quadrants!</p> [[Image:ShadowAssess2.jpg]] <p>With photographic prints, an exposure will yield a print that is unacceptably light at the minimal exposure, then gets darker with more exposure, with the shadows filling in and detail filling in in the highlights, until there is too much exposure and the shadows block up and the highlights become light grey instead of having just the touch of density to give shading.</p> <p>In a holographic test strip, what will be observed is that the image will get brighter and brighter, but after a certain point the shadows will start losing contrast and not look very dark black but take on a powdery look, caused by crystals that were over-exposed and should have not been developed.</p> [[Image:CWC22DTS.jpg]] <p>Simply looking at the hologram with a black backing, velvet or velour is best as their fibrous nature is a good light trap, and seeing the where the brightest image occurs.&nbsp; In the example above, a Kodak 18% reflective Grey Card is on the right for comparison purposes. Notice that there are 8 steps to this exposure test.</p> <p>If attempting this for the first time, the first best guesstimate may be grossly over but more than likely under-exposed.&nbsp; In the sample below the upper left exposure, the longest one in this case, is above threshold and all the rest are under threshold.&nbsp; Notice that this one was shot with a less than full plate spread, so you can see the exposure fall off due to the non-uniform Gaussian beam profile.&nbsp; The next shot should start with this longest exposure and go higher and higher.</p> [[Image:BayerThreshold copy.jpg]] <p>This one on the other hand was very much over exposed and/or over-developed.&nbsp; For the next trial, start with the lowest dose and work downward. There is such a thing as too much!</p> [[Image:Overdone.jpg]] <p align="left">The student will realize that they have arrived at the best possible exposure time when the image pops out, and the viewer doesn't have to squint and squirm to see what's behind the glass. A properly exposed plate will reproduce an image that looks solid, and without a haze that makes it look like it's underwater. Comparison to commercially available holographic images (but not the embossed ones on foil, nor the dichromated gelatin types, but other silver halide based materials) might prove surprising!</p> f5d61df9b9f0d465056f82c4f18a7b694fc2ad69 0 1024 2284 2014-01-01T05:01:53Z Jsfisher 1 Created page with "== Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] *..." wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div. ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 63a286d890f8b55803840365615fac2f54bf262e 2285 2284 2014-01-01T05:03:20Z Jsfisher 1 wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] a5b19a2cadcf27eca7fe48c794f63044bf93a7e9 2319 2285 2014-01-01T06:29:24Z Jsfisher 1 /* = Ascorbic acid */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 19b1e49d7b35e1fbe8ec7ca7fc0b5a51833427b4 6 1025 2286 2014-01-01T05:22:37Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1026 2287 2014-01-01T05:22:46Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1027 2288 2014-01-01T05:23:31Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1028 2289 2014-01-01T05:23:42Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1029 2290 2014-01-01T05:23:46Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1030 2291 2014-01-01T05:24:57Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1031 2292 2014-01-01T05:25:02Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1032 2293 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2014-01-01T05:26:17Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 2318 2301 2014-01-01T06:25:46Z Jsfisher 1 Jsfisher uploaded a new version of &quot;[[File:7SBP86.PDF]]&quot; wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1041 2302 2014-01-01T05:26:33Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1043 2304 2014-01-01T05:42:45Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 1044 2305 2014-01-01T05:50:41Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1045 2306 2014-01-01T05:50:51Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1046 2307 2014-01-01T05:53:43Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1047 2308 2014-01-01T05:53:47Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1048 2309 2014-01-01T05:53:49Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1049 2310 2014-01-01T05:53:52Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1050 2311 2014-01-01T05:53:57Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1051 2312 2014-01-01T05:54:00Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1052 2313 2014-01-01T05:54:06Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1053 2314 2014-01-01T05:55:29Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1054 2317 2014-01-01T06:11:20Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 952 2320 2210 2014-01-01T15:21:41Z Jsfisher 1 /* Hologrammy */ wikitext text/x-wiki The following pages were derived from Ed Wesly's web pages at http://nlutie.net/ewesly. = Hologrammy = {| |- | * [[Ewesly / Holographic Pedagogy | Holographic Pedagogy]] * [[Ewesly / Holographic R&D | Holographic R&D]] * [[Ewesly / Holographic Artwork | Holographic Artwork]] * [[Ewesly / Holographic Formulae | Holographic Formulae]] * [[Ewesly / Publications | Publications]] * [[Ewesly / The New Adventures of Hans and Ed | The NEW Adventures of Hans and Ed]] * [[Ewesly / Holographic Consumer Reports | Holographic Consumer Reports]] | [[Image:WinterWonderlandCsm.jpg|right]] |} 5cd918848acaca3b337cea7f91f961da15537b1a 6 1055 2321 2014-01-01T16:24:33Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 1056 2322 2014-01-01T16:24:49Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 1057 2323 2014-01-01T16:25:04Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 6 1058 2324 2014-01-01T16:25:26Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 1060 2326 2014-01-01T17:34:57Z Jsfisher 1 Created page with "= Silver Halide Holograpic Recording Materials 2000 = ''''M³ Visual Research Laboratory''''<ref>aka The Home & Studio of E. Wesly + Sons</ref>, as a service to the..." wikitext text/x-wiki = Silver Halide Holograpic Recording Materials 2000 = ''''M³ Visual Research Laboratory''''<ref>aka The Home & Studio of E. Wesly + Sons</ref>, as a service to the holographic community, is proud to present a <b>Consumer Report</b> on the state of the art of silver halide holographic recording materials. In the wake of the demise of Agfa's Holotest line up there is a real need for a suitable substitute, hopefully one that is brighter, less noisy, and less expensive. My Artist-Photographer Zone System<ref>See for example, Zone System Manual, Ansel Adams, the negative, etc.</ref> training compels me to carry out these tests, as understanding the materials results in more control in realizing the final result. As Ruben Nunez has said,<ref>Private conversation, circa 1983.</ref> we <u>need</u> a <i>Minister of Brightness</i>. I myself am curious as to what is up with these new products. However, I do not have much faith in literature published by manufacturers, or reports of other holographers who do not test other products side by side, or their technique which may be sloppier than mine. To be really fair, rigorous testing needs to be done, which is usually too boring to be undertaken by the typical holographer. We purchased samples of five different red-sensitive holographic recording materials: HRT BB-640, two flavors of Slavich plates, PFG-01 and PFG-O3M, plus some Chinese plates from Control Optics. All were of the same 63 by 63 mm or 2 1/2&quot; squares coated on glass, except for the Chinese plates, which were delivered as a sample package of four 4&quot; by 5&quot; glass plates. Two different sources were used to procure the Russian plates, yet they both bungled the job.<ref>Names withheld to protect the guilty!</ref> I wanted some PFG-03M plates, the ones that are legendary for ultra-fine grain, in the vicinity of 10 nanometers. From the one I received PFG-03<b><u>C</u> </b>plates, which is the true color or panchromatic emulsion. But it nevertheless has the teeny grains, so I thought I was happy. Until I opened the box! There were only 20, not 30 in it! From the other source I got another box of PFG-01 instead of PFG-03M. Although I had asked for them over the phone with a verbal description, I guess I had to be more precise with the exact alphanumeric code to avoid confusion. <u>Russian Plate Scorecard:</u> So I ended up with twice as many PFG-01 plates that I had wanted, no PFG-03M which I wanted most desperately, and something I didn't necessarily want, PFG-03C. I was introduced to the field of holography over twenty years ago at a photography teachers convention, wherein TJ*** not only showed some Russian holograms but also made a couple of holograms in front of a group of people. A day that changed my life! And he showed off some Russian holograms. It is hard to believe that now I can have my own Russian holo plates. <b>PACKAGING:</b> The Slavich plates are packed in cute little plastic boxes, not unlike the familiar Empak ones that the Agfa products came in. But they were not all that well-molded, and were difficult to open, which is what it should be, to avoid accidents, but were even harder to close properly, and sometimes gave the feeling that the job was not done well enough to be light-tight. <i>Cardboard</i> is the word for BB-640 plates' packaging and shame on you. There is a triple box made out of heavy card stock, with a black plastic bag sealing the plates inside from humidity. The plates are stacked inside the light tight baggy, with cardboard interleavings. Tacky, tacky, tacky! I haven't seen any scratches yet, but then I've only shot only a few. I transferred them to a traditional Empak box emptied of its Agfa plates.<ref>It never failed to amaze me that those slick black boxes were made by Empak, in a suburb of Minneapolis, Minnesota, USA, shipped across the ocean, filled with the Lippmann emulsions in Belgium and back here again. I wonder how much that added to the price of the plates.</ref> The four Chinese 4&quot; by 5&quot; plates were simply wrapped in black paper and thrown in a box with styrofoam peanuts. To separate them small dots of paper were folded over some of the edges. Admittedly these were a sample package, but it doesn't inspire confidence in the product by the cavalier manner that they were shipped. How could you use a scratched plate in an art piece? As a standard of comparison, some plates from my secret stash, an unopened box of Agfa Holotest 8E75HD, batch # 591304, expiration date of 02/00, were exposed and processed alongside the rest. <b><u>PHASE ONE: ON AN EQUAL FOOTING</u></b> To start off with all things being equal, plates from all boxes were exposed with a series of exposures and developed in the developer that has been the household standard for so long, <b>CWC2</b>, with an immersion time of two minutes. (For more details about the process, see the <b>Handout, CWC2</b>.) This developer bleach combination gets a high brightness out of the Holotest material, signal to noise is directly related developed density, and there is no distortion of the fringes, as the plate can be replaced onto the object and real-time fringes can be observed! The hologram casts a very dark shadow on the object as it steals reference beam light. The CWC2 process and Holotest materials are as peaked as perfectly as possible for this application. It used to be the standard of the industry. Let us see if the new materials can beat it. For this phase of testing the qualities that the holographic samples are judged on are brightness, signal to noise ratio, and replay wavelength fidelity. The last aspect is important for making copies of reflection holograms, with either contact or separated geometries. Sometimes a different replay color is desired for display purposes, but shrinkage to shorter wavelength replay shows that the material is not replaying the recorded fringe pattern as faithfully as it should. <b>BLEACHING:</b> I know that this will upset many of you right off, but the bleach that I used for these tests was the dreaded <b>CWPBQ2</b>, for a variety of reasons. First off, I paid $26.10 for a half pound of it 15 years ago, and being a holographic cheapskate I want to use it up. But most importantly, when it is used with the CWC2 developer, it yields a hologram whose fringes are distortion free, as evidenced by brightest replay at the recording angle and the possibility of producing real-time interferometric fringes when the plate is replaced exactly on the object holder. Using the two nested trays method contains the obnoxious odor. Most of the other rehalogenating bleaches that I have tested (see the <b>Handout, ROUNDUP '90</b>) work pretty much the same, except the Ferric EDTA ones usually exhibit noticeable shrinkage, and the Copper Sulfate prints out like crazy. Just pick your poison. I didn’t have time to investigate solvent bleaches, to induce shrinkage to shorter replay wavelengths. <b><u>EXPOSURE METHODLOGY:</u></b> The tried and true <i>Standard Object</i> was dusted off for the exposure testing series, which is an antique waffle iron mold sprayed with <b>Krylon #1401 Bright Silver</b>. This paint uses aluminum flakes for its pigment, which in addition to being highly reflective, preserves polarization vectors. The waffle iron is a not too deep object, with a homogenous background. A series of exposures can be made on one plate with each quadrant having an identical scene. Plus when viewed pseudoscopically it looks like the waffle itself! Three ball bearings support the plate so it doesn’t rock. A bar prevents it from sliding down and blocks light from entering the edge of the plate. The iron mold is supported in a kind of goal post arrangement so that it can be tilted to give a decent reference angle, which was about 30 degrees from the normal in this case to prevent the shadows of the waffle texture from getting too long. Figure One shows the rig with a processed plate replaced back into its exposed position generating real-time interferometric fringes, demonstrating the stability of the kinematic device. [[File:HCRGimage002.gif|right]Kinematic Plateholding Object, demonstrating real-time holographic fringes on a well-processed plate.] The <b>isolation system</b> was my unpatented <b>BIG BEAM</b> as featured in a variety of articles. Photons supplied by a Melles Griot LHP 171 7 mW He-Ne, spatially filtered by Jodon. Incident flux was measured by a borrowed Newport 820 at 40 microWatts per square centimeter. One quarter of a cardboard square the same size as the plates was cut out, so that &frac34; of the plate was blocked while one quadrant was exposed. Exposure doses varied with the material, with the Agfa and PFG-01 receiving 50 microJoules per cm² minimally and going on up to 3200 microJoules per cm² for the tiny grainers. The exposure doses are given on a label attached to the center of the plate in most of the following photos. Exposure times varied from 1.25” for 50 μJ/cm² on up to 80” for the longest 3.2 millJoules per cm². <b><u>RESULTS:</u></b> Figure Two shows the preliminary holograms. The standard of comparison was the Holotest, and this batch exhibited behavior like all the prior ones: a threshold of image visibility at about 50 μJ/cm2, increasing brightness until that peaks at around 200 μJ/cm2, and at exposure doses beyond that the plate gets very noisy. [[File:HCRGimage004.gif|right|All samples developed in CWC2 and bleached in CWPBQ2. Unpainted backs, holograms laid on a piece of black velvet.]] The PFG-01 is claimed to be a drop-in replacement for the above. When exposed and processed alongside the Agfa, it is a close match in brightness but the obvious winner in signal to noise.It also could produce real time fringes when positioned on the object. I had heard that the HRT BB-640 would need more exposure than the Agfa, so I started with 200 μJ/cm² and worked up to 1600 μJ/cm² or 1.6 milliJoules/cm². The color was orangey, brightness not as good as the others, but this was the lowest noise so far. Hopefully using its own developer will improve the situation, as it is so nice to see almost transparent glass in the darkest areas, as opposed to the veiling haze of scatter with the two above. I gave the same exposure series to the Control Optics plates, but they shrank into the green! Their instructions say to use a modified CWC2 developer, which is just the usual formulation <i>sans</i> urea. This makes sense since the urea is a penetrant, a gelatin softener, and it let the layer shrink to the green. We never got around to seeing what its deletion does because the plates were destroyed while cutting the 4” by 5”s down to 2 &frac12;” squares. The glass was thinner than the usual 1.5 mm of Agfa. Otherwise the brightness and noise were not unlike the BB-640. The Slavich PFG-03C also suffered from serious shrinkage. (Not shown.) Its instruction sheet mentions a Hardener step, which would have been implemented in the next round of testing, if it were not noticed that the material had arrived fogged. There was a gross white haze around the edges of the hologram. When an unexposed plate was plopped into the developer, it almost uniformly darkened. After a few phone calls the situation was straightened out and I received a nice fresh box of Slavich PFG-03M, which was what I had desired all along. The results were not all that bright when done in this manner. At the end of Round One of Phase One it seems that the PFG-01 is truly a drop-in replacement for Agfa Holotest 8E75HD. Its peak brightness comes at a lower density, with slightly less noise, maybe because as Ilford had always claimed Agfa had quite a few huge (relatively) &quot;rogue grains&quot; floating around which may have been the major contributing factor to noise as well as density. It is surprising that its sensitivity is pretty much exactly the same as Agfa's! The Slavich chemists had certainly done a good job of reverse engineering the Agfa plates. The other materials do not seem to be peaked with this processing scheme. The shifted replay color and not all that dazzling efficiency (albeit low noise!) points out that we should check out the instruction sheets<ref>Tell the tales of woe of the instruction sheets, including how worthless the Agfa ones were. Holographic paper collectors.</ref> for these materials to see what the manufacturers' suggest. <b><u>PHASE TWO: A PROCESSING SCHEME OF THEIR OWN</u></b> What a surprise! Following the manufacturers’ recommendations improved the quality of the holograms! I opted to optimize the German material, HRT BB-640 next. Of all the materials it looked the cleanest, and with CWC2 had better sensitivity than either the Chinese plates or Slavich PFG-03C or M. So I mixed up a batch of &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; BBAA DEVELOPER {| class="wikitable" border="1" |- | 70 g | Sodium Carbonate |- | 15 g | Sodium Hydroxide |- | 4 g | Metol |- | 26 g | Ascorbic Acid |- | 1 L | Water |} The Sodium Carbonate and Hydroxide are there to provide the necessary alkalinity. This bath measures 11.5pH with paper pH strips, which is quite high, and is due mainly to the NaOH. There's a lot more Metol here than in Kodak D-19, and it may keep grain growth down while initiating developer sites. This formula sets a record for <b>A</b>scorbic <b>A</b>cid content in a developer. The Vitamin C produces a satisfying fizzing sound when dumped into the Drano/Washing Soda solution. No developing times or temperatures were given, only the guideline of a density of 2.5. You're on your own on how to get there. With all the developing agents and the high pH, you would expect that it be a highly energetic developer. And that may be just what it takes to get this emulsion to perform to its utmost. For the resulting holograms were extremely bright and low noise! The best tested so far. But the replay color is shifted from the He-Ne red, although it does replay at that wavelength, albeit with a bit of tilt. Developed in the above stew and bleached in PBQ, I got extremely good efficiency and signal to noise ratio! But since the replay color was not quite the same as the laser’s, something must be screwy with the gelatin of this emulsion. It is shrinking after processing, both with this developer and CWC2. A trick that I would use to retain original Bragg plane spacing with the Ilford emulsions having the BIPS<ref>Built-In Pre-Swell, so that the replay color was automatically shifted about 25-35 nanometers even when using a develop-rehalogenating bleach scheme, which should retain the recording fringe pattern spacing. To retain laser color fidelity this bloating agent had to be washed out <u>before</u> exposure. Nobody should be forced to handle things in the dark more than is necessary, especially since the emulsion could be damaged or fogged before shooting the hologram. Let's hope nobody else is brilliant enough to come up with that marketing scheme again! The problems it created! Why put something in that nobody really needed?</ref> ingredient would be to develop in a pyro-based developer and bleach with PBQ. When pyrogallol develops, it tans the gelatin surrounding the developing grain with its by-products. The gelatin is hardened while it is swollen with water, and it does not collapse as much as it would in a non-tanning developer. Comparing two holographic exposure series plates on Holotest, both developed to the same densities, one in PyroChrome developer and the other in the not-so-tanning CWC2, the same amount of developed silver got removed in the silver solvent 'Chrome bleach, but the higher structural integrity of the gelatin as a result of the tanning results in less shrinkage and not as green a color shift. The problem with this scheme of color control is that the plumping up of the emulsion is dependent on developed density. The tanning needs to compensate for the natural shrinkage of the gelatin. Usually with the Ilford material one of the exposures produced enough tanning action that the desired effect of real-time fringes could be observed. So there is a formula included with the BB instructions for a Pyrogallol based developer that I figured would be as energetic as their Vitamin C soup. <b>BB PYRO DEVELOPER</b> {| class="wikitable" border="1" |- | Part A | | | | 15 g | Pyrogallol | | 5 g | Metol | | 1 L | Water | Part B | | | | 30 g | Sodium Carbonate | | 7 g | Sodium Hydroxide | | 1 L | Water |} As is typical with the short-lived pyro concoctions, the two parts are mixed together immediately before use. The pyrogallol concentration is 50% higher than that of the original <i>Pyrochrome</i> recipe, and there is yet another boost to activity with the Metol, which may have a super-additive effect. I followed this developer with rehalogenating CWPBQ2, not with the dichromate based reversal bleach as recommended in the BB instruction sheet, because I wanted to overcome the shrink of the gelatin and not induce any more wavelength shifting to the green, as what would happen using the latter bleach. Development time with both of these developers was five minutes, with an ambient temperature of Chicago Spring of 72F. Keeping the development time constant and letting the exposure time determine the final density build up yields more easily repeatable results. Five minutes (a couple of good songs) is the maximum I am willing to wait for results. This developer gave the minimal amount of shrinkage, yielding real-time fringes on the kinematic holder, and a really nice signal to noise ratio. But I wasn’t satisfied with the shrinkage of the BB AA developer, so I tried another High Energy developer, Kodak D-8. (I only used 2’ development time as there was a danger of fogging.) The pH of this one is way up there with the other two, and with its high hydroquinone content it really builds up density! Figure Three shows all three developers’ results.<o:p></o:p></span></p> [[File:HCRGimage006.gif|right|BB 640 and 3 Developers, BB Pyro, Kodak D-8, and BB AA, all with CWPBQ2 Bleach. On the left the replay color is laser perfect, the middle an orangey-yellow, and the right a yellowy-green.]] <b>SLAVICH PFG-03M:</b> When I finally received what I had been looking for I couldn't believe it; here in my hot little hands were samples of the famed Russian holographic technology. High efficiency, high signal to noise and of course the dreaded low sensitivity. But the quality of the hologram should be worth all the sacrifice. So I started with the classic CWC2, and it was barely OK, as evidenced in Figure Two. Conventional holographic wisdom (or is it lore?) that the Russian emulsions demanded colloidal development because of the super-fine grains. But I had previously tried the typical Western processing scheme on some Bulgarian Holographic Plates in the late ‘80’s. In the summer of 1982, Dr. V. C. Sainov brought a bunch of holographic plates that had been manufactured by the Bulgarian Academy of Sciences. They came in two flavors, HP-490 whose sensitivity peaked at 490 but continued on to at least 515 nm Argon green, and HP-650 plates with red sensitivity. He also had his own proprietary developer, FHP-3. We attempted to record holograms with these materials when experimenting with true color holography although these plates had been sitting in an attic for approximately seven years. The HP-650 was officially pronounced dead on arrival, but the HP-490 still had some life left in them. No fog was found when an unexposed plate was put into the developer, but there was some &quot;development&quot; in the form of shiny silver deposits around the edges of the plates where they had been in contact with some black packing paper. Perhaps some sulfur compounds used to make the paper black were to blame for reducing the silver bromide. Since we didn't have any of the recommended FHP-3 colloidal developer, we processed the plates in a developer - rehalogenating scheme using the CWC2 developer and CWPBQ2 bleach. The results were quite good, with fairly high efficiency and an incredibly high signal to noise ratio, at all wavelengths we tested, even down to 458 nm. But at what a price! The exposures were in the 20 to 80 <u>milli</u>Joules/cm2 range, about two orders of magnitude away from the Agfa plates, which were requiring 200 microJoules/cm2 for 8E56HD at 515 nm or 800 microJoules at the same wavelength for 8E75HD. You should expect to see dichromated gelatin performance at these exposure levels, which the material delivers with respect to signal to noise, but not so much in efficiency. The ten nanometer grains keep scatter to a minimum, but are not so efficient in capturing photons. Plus there are not enough of them to provide a very reflective Bragg layer. I had gotten comfortable with developing for only two minutes, but with these super slow plates four might be a better idea. It's only two extra minutes, but it can seem like an eternity.<ref>Let's have a contest to see who has the wildest things to do while wiling away the settling and developing times. What is on <u>your</u> mind?</ref> So it didn’t seem to unusual to process this way. But it seems that the GP2 formula is necessary for the best results on PFG-03M as of this writing. The first that I had ever heard of it was on a mimeographed sheet handed out by Nick Phillips at the 1982 ISDH.<ref>I still have it in my permanent collection! The earliest publication that I have of the formula in my collection is Ostrovski,...</ref> Even that scholarly tome, Hans Bjelkhagen’s book, gives the formula but does not state its origins. The rule is not to agitate in this bath. So I just put the plate in a photographic film developing tank (without the reel!) and closed the lid, sitting my trusty Gra-Lab timer (the backwards going clock) for 15 minutes and let it simmer. The instruction sheet says immersion of 10 to 15 minutes, and figuring that the Helium Neon holographer needs all the speed out of the material, I used 15 minutes. Even with the long development time, I needed 80 second exposures! (HD needs only 5&quot;!) I used Edwal non-hardening fixer as I had some mixed up for black and white photographic printing. The Slavich fixer formulation is rather simple, just Sodium Thiosulfate with some Potassium Metabisulfite as a preservative. I didn't have any of the latter on hand, and wasn't in a mood to order some. This worked just peachy. After drying the image looked very bright and clean. The plate itself was not transparent like the others processed in the develop bleach regime, but it was of that reddish-brown color indicative of colloidal development. This added to the signal to noise ratio. And it was capable of real-time fringes, as the developed layer color had only fairly low density at 633 nm. When flipping over the plate and illuminating the emulsion side to observe the real image, the image color looks a little chirped; it is not a red color, but kind of pink. So it appears that if the final holographic result is to be displayed pseudoscopically, it should be exposed with its emulsion away from the object. (Maybe this is an artifact of not using their fixer?) Because I am of the old hard core school of develop and bleach, I tried Kodak D-8 as the developer. But this doesn't look so hot, so it’s not illustrated. <b>THE PRE-HARDENER PROBLEM:</b> The idea of pre-hardening the plates doesn't seem like such a good idea to me. The only photographic process that comes to mind that requires such a step was the old Ektachrome E-4 color process. The untreated film was not capable of withstanding the high temperatures necessary for short process times, so this pre-developer step was added. But what really makes me queasy are two of the constituents of the solution; Formaldehyde and potassium bromide. Formalin solution is not easy to come by; even just having the stuff in a darkroom doesn't sit right with me. It belongs in an embalming room<ref>I got mine from my undertaker buddies.</ref> Perhaps in Eastern Europe this stuff isn't considered that dangerous, but here you will be paying a bundle in Hazardous Material Shipping Charges! The other component in this bath that raises one of my eyebrows is the potassium bromide. I know from experience that solutions of bromide can <u>erase</u> a latent image!<ref>My own paper, Recycling of Holographic Plates... Sorry for the sketch footnotes! Maybe when this gets published for real!</ref> Although it is a minute amount, anything that slows these plates down should be avoided. But just for the sake of you, dear readers, I got ahold of some Formalin solution and made up a batch of this toxic waste. It appears to be necessary for the -03 emulsions. [[File:HCRGimage008.gif|right|The Ultra-Fine Grained Crew. It seems like a tie between the BB 640 developed with Pyro and bleached in PBQ and the PFG-03M and its GP2 colloidal developer.]] <b>CONCLUSIONS:</b> Figure Five shows the full-plate holograms using the best exposure and developer combination based on the above trial and error exposure tests, 200 μJ/cm² for the larger grained Holotest and PFG-01, 3.2 mJ/cm² for the finer grained. They are illuminated on the flip or pseudoscopic side, so they look like bite-sized tasty morsels of that Belgian treat. The chirped aspect of the PFG-03M is visible from this, the emulsion side, but it looks narrow-band red through the glass. Go figure. We are looking at the emulsion side of this batch in this picture because I painted the glass side with black spray paint to give a better idea of the signal to noise of the emulsion. They were photographed against a Kodak 18% Gray Card to give some idea of relative diffraction efficiency. [[File:HCRGimage010.gif|right]] <b>PRICING:</b> This is where it gets mind-boggling. One would think that the new kids on the block would try to not repeat the mistake of Agfa and charge an arm and a leg, but they do. Agfa got caught up in an inflationary spiral; the plates weren't selling, so they had to charge more. And then less people bought, so they charged even more. I remember when the HD series came out around 1980 and 4&quot; by 5&quot;'s were only about $2. At the end, they were $8, which is out of sync with the rest of the cost of living price increases. So I hope that this Holographic Consumer Report will help others spend their hard-earned dough wisely! <references /> aka The Home &amp; Studio of E. Wesly + Sons Names withheld to protect the guilty! It never failed to amaze me that those slick black boxes were made by Empak, in a suburb of Minneapolis, Minnesota, USA, shipped across the ocean, filled with the Lippmann emulsions in Belgium and back here again. I wonder how much that added to the price of the plates. Built-In Pre-Swell, so that the replay color was automatically shifted about 25-35 nanometers even when using a develop-rehalogenating bleach scheme, which should retain the recording fringe pattern spacing. To retain laser color fidelity this bloating agent had to be washed out <u>before</u> exposure. Nobody should be forced to handle things in the dark more than is necessary, especially since the emulsion could be damaged or fogged before shooting the hologram. Let's hope nobody else is brilliant enough to come up with that marketing scheme again! The problems it created! Why put something in that nobody really needed? Let's have a contest to see who has the wildest things to do while wiling away the settling and developing times. What is on <u>your</u> mind? I got mine from my undertaker buddies. [1] See for example, Zone System Manual, Ansel Adams, the negative, etc. [2] Private conversation, circa 1983. [3] Tell the tales of woe of the instruction sheets, including how worthless the Agfa ones were. Holographic paper collectors. [4] I still have it in my permanent collection! The earliest publication that I have of the formula in my collection is Ostrovski,... [5] My own paper, Recycling of Holographic Plates... Sorry for the sketch footnotes! Maybe when this gets published for real! 330736fd497c0d090ec30466ed24c5bee2061b73 2327 2326 2014-01-01T17:41:57Z Jsfisher 1 wikitext text/x-wiki = Silver Halide Holograpic Recording Materials 2000 = ''''M³ Visual Research Laboratory''''<ref>aka The Home & Studio of E. Wesly + Sons</ref>, as a service to the holographic community, is proud to present a <b>Consumer Report</b> on the state of the art of silver halide holographic recording materials. In the wake of the demise of Agfa's Holotest line up there is a real need for a suitable substitute, hopefully one that is brighter, less noisy, and less expensive. My Artist-Photographer Zone System<ref>See for example, Zone System Manual, Ansel Adams, the negative, etc.</ref> training compels me to carry out these tests, as understanding the materials results in more control in realizing the final result. As Ruben Nunez has said,<ref>Private conversation, circa 1983.</ref> we <u>need</u> a <i>Minister of Brightness</i>. I myself am curious as to what is up with these new products. However, I do not have much faith in literature published by manufacturers, or reports of other holographers who do not test other products side by side, or their technique which may be sloppier than mine. To be really fair, rigorous testing needs to be done, which is usually too boring to be undertaken by the typical holographer. We purchased samples of five different red-sensitive holographic recording materials: HRT BB-640, two flavors of Slavich plates, PFG-01 and PFG-O3M, plus some Chinese plates from Control Optics. All were of the same 63 by 63 mm or 2 1/2&quot; squares coated on glass, except for the Chinese plates, which were delivered as a sample package of four 4&quot; by 5&quot; glass plates. Two different sources were used to procure the Russian plates, yet they both bungled the job.<ref>Names withheld to protect the guilty!</ref> I wanted some PFG-03M plates, the ones that are legendary for ultra-fine grain, in the vicinity of 10 nanometers. From the one I received PFG-03<b><u>C</u> </b>plates, which is the true color or panchromatic emulsion. But it nevertheless has the teeny grains, so I thought I was happy. Until I opened the box! There were only 20, not 30 in it! From the other source I got another box of PFG-01 instead of PFG-03M. Although I had asked for them over the phone with a verbal description, I guess I had to be more precise with the exact alphanumeric code to avoid confusion. <u>Russian Plate Scorecard:</u> So I ended up with twice as many PFG-01 plates that I had wanted, no PFG-03M which I wanted most desperately, and something I didn't necessarily want, PFG-03C. I was introduced to the field of holography over twenty years ago at a photography teachers convention, wherein TJ*** not only showed some Russian holograms but also made a couple of holograms in front of a group of people. A day that changed my life! And he showed off some Russian holograms. It is hard to believe that now I can have my own Russian holo plates. <b>PACKAGING:</b> The Slavich plates are packed in cute little plastic boxes, not unlike the familiar Empak ones that the Agfa products came in. But they were not all that well-molded, and were difficult to open, which is what it should be, to avoid accidents, but were even harder to close properly, and sometimes gave the feeling that the job was not done well enough to be light-tight. <i>Cardboard</i> is the word for BB-640 plates' packaging and shame on you. There is a triple box made out of heavy card stock, with a black plastic bag sealing the plates inside from humidity. The plates are stacked inside the light tight baggy, with cardboard interleavings. Tacky, tacky, tacky! I haven't seen any scratches yet, but then I've only shot only a few. I transferred them to a traditional Empak box emptied of its Agfa plates.<ref>It never failed to amaze me that those slick black boxes were made by Empak, in a suburb of Minneapolis, Minnesota, USA, shipped across the ocean, filled with the Lippmann emulsions in Belgium and back here again. I wonder how much that added to the price of the plates.</ref> The four Chinese 4&quot; by 5&quot; plates were simply wrapped in black paper and thrown in a box with styrofoam peanuts. To separate them small dots of paper were folded over some of the edges. Admittedly these were a sample package, but it doesn't inspire confidence in the product by the cavalier manner that they were shipped. How could you use a scratched plate in an art piece? As a standard of comparison, some plates from my secret stash, an unopened box of Agfa Holotest 8E75HD, batch # 591304, expiration date of 02/00, were exposed and processed alongside the rest. <b><u>PHASE ONE: ON AN EQUAL FOOTING</u></b> To start off with all things being equal, plates from all boxes were exposed with a series of exposures and developed in the developer that has been the household standard for so long, <b>CWC2</b>, with an immersion time of two minutes. (For more details about the process, see the <b>Handout, CWC2</b>.) This developer bleach combination gets a high brightness out of the Holotest material, signal to noise is directly related developed density, and there is no distortion of the fringes, as the plate can be replaced onto the object and real-time fringes can be observed! The hologram casts a very dark shadow on the object as it steals reference beam light. The CWC2 process and Holotest materials are as peaked as perfectly as possible for this application. It used to be the standard of the industry. Let us see if the new materials can beat it. For this phase of testing the qualities that the holographic samples are judged on are brightness, signal to noise ratio, and replay wavelength fidelity. The last aspect is important for making copies of reflection holograms, with either contact or separated geometries. Sometimes a different replay color is desired for display purposes, but shrinkage to shorter wavelength replay shows that the material is not replaying the recorded fringe pattern as faithfully as it should. <b>BLEACHING:</b> I know that this will upset many of you right off, but the bleach that I used for these tests was the dreaded <b>CWPBQ2</b>, for a variety of reasons. First off, I paid $26.10 for a half pound of it 15 years ago, and being a holographic cheapskate I want to use it up. But most importantly, when it is used with the CWC2 developer, it yields a hologram whose fringes are distortion free, as evidenced by brightest replay at the recording angle and the possibility of producing real-time interferometric fringes when the plate is replaced exactly on the object holder. Using the two nested trays method contains the obnoxious odor. Most of the other rehalogenating bleaches that I have tested (see the <b>Handout, ROUNDUP '90</b>) work pretty much the same, except the Ferric EDTA ones usually exhibit noticeable shrinkage, and the Copper Sulfate prints out like crazy. Just pick your poison. I didn’t have time to investigate solvent bleaches, to induce shrinkage to shorter replay wavelengths. === Exposure Methodology === The tried and true <i>Standard Object</i> was dusted off for the exposure testing series, which is an antique waffle iron mold sprayed with <b>Krylon #1401 Bright Silver</b>. This paint uses aluminum flakes for its pigment, which in addition to being highly reflective, preserves polarization vectors. The waffle iron is a not too deep object, with a homogenous background. A series of exposures can be made on one plate with each quadrant having an identical scene. Plus when viewed pseudoscopically it looks like the waffle itself! Three ball bearings support the plate so it doesn’t rock. A bar prevents it from sliding down and blocks light from entering the edge of the plate. The iron mold is supported in a kind of goal post arrangement so that it can be tilted to give a decent reference angle, which was about 30 degrees from the normal in this case to prevent the shadows of the waffle texture from getting too long. Figure One shows the rig with a processed plate replaced back into its exposed position generating real-time interferometric fringes, demonstrating the stability of the kinematic device. [[File:HCRGimage002.gif|right]Kinematic Plateholding Object, demonstrating real-time holographic fringes on a well-processed plate.] The <b>isolation system</b> was my unpatented <b>BIG BEAM</b> as featured in a variety of articles. Photons supplied by a Melles Griot LHP 171 7 mW He-Ne, spatially filtered by Jodon. Incident flux was measured by a borrowed Newport 820 at 40 microWatts per square centimeter. One quarter of a cardboard square the same size as the plates was cut out, so that &frac34; of the plate was blocked while one quadrant was exposed. Exposure doses varied with the material, with the Agfa and PFG-01 receiving 50 microJoules per cm² minimally and going on up to 3200 microJoules per cm² for the tiny grainers. The exposure doses are given on a label attached to the center of the plate in most of the following photos. Exposure times varied from 1.25” for 50 μJ/cm² on up to 80” for the longest 3.2 millJoules per cm². == Results == Figure Two shows the preliminary holograms. The standard of comparison was the Holotest, and this batch exhibited behavior like all the prior ones: a threshold of image visibility at about 50 μJ/cm2, increasing brightness until that peaks at around 200 μJ/cm2, and at exposure doses beyond that the plate gets very noisy. [[File:HCRGimage004.gif|right|All samples developed in CWC2 and bleached in CWPBQ2. Unpainted backs, holograms laid on a piece of black velvet.]] The PFG-01 is claimed to be a drop-in replacement for the above. When exposed and processed alongside the Agfa, it is a close match in brightness but the obvious winner in signal to noise.It also could produce real time fringes when positioned on the object. I had heard that the HRT BB-640 would need more exposure than the Agfa, so I started with 200 μJ/cm² and worked up to 1600 μJ/cm² or 1.6 milliJoules/cm². The color was orangey, brightness not as good as the others, but this was the lowest noise so far. Hopefully using its own developer will improve the situation, as it is so nice to see almost transparent glass in the darkest areas, as opposed to the veiling haze of scatter with the two above. I gave the same exposure series to the Control Optics plates, but they shrank into the green! Their instructions say to use a modified CWC2 developer, which is just the usual formulation <i>sans</i> urea. This makes sense since the urea is a penetrant, a gelatin softener, and it let the layer shrink to the green. We never got around to seeing what its deletion does because the plates were destroyed while cutting the 4” by 5”s down to 2 &frac12;” squares. The glass was thinner than the usual 1.5 mm of Agfa. Otherwise the brightness and noise were not unlike the BB-640. The Slavich PFG-03C also suffered from serious shrinkage. (Not shown.) Its instruction sheet mentions a Hardener step, which would have been implemented in the next round of testing, if it were not noticed that the material had arrived fogged. There was a gross white haze around the edges of the hologram. When an unexposed plate was plopped into the developer, it almost uniformly darkened. After a few phone calls the situation was straightened out and I received a nice fresh box of Slavich PFG-03M, which was what I had desired all along. The results were not all that bright when done in this manner. At the end of Round One of Phase One it seems that the PFG-01 is truly a drop-in replacement for Agfa Holotest 8E75HD. Its peak brightness comes at a lower density, with slightly less noise, maybe because as Ilford had always claimed Agfa had quite a few huge (relatively) &quot;rogue grains&quot; floating around which may have been the major contributing factor to noise as well as density. It is surprising that its sensitivity is pretty much exactly the same as Agfa's! The Slavich chemists had certainly done a good job of reverse engineering the Agfa plates. The other materials do not seem to be peaked with this processing scheme. The shifted replay color and not all that dazzling efficiency (albeit low noise!) points out that we should check out the instruction sheets<ref>Tell the tales of woe of the instruction sheets, including how worthless the Agfa ones were. Holographic paper collectors.</ref> for these materials to see what the manufacturers' suggest. <b><u>PHASE TWO: A PROCESSING SCHEME OF THEIR OWN</u></b> What a surprise! Following the manufacturers’ recommendations improved the quality of the holograms! I opted to optimize the German material, HRT BB-640 next. Of all the materials it looked the cleanest, and with CWC2 had better sensitivity than either the Chinese plates or Slavich PFG-03C or M. So I mixed up a batch of <b>BBAA DEVELOPER</b> {| class="wikitable" border="1" |- | 70 g || Sodium Carbonate |- | 15 g || Sodium Hydroxide |- | 4 g || Metol |- | 26 g || Ascorbic Acid |- | 1 L || Water |} The Sodium Carbonate and Hydroxide are there to provide the necessary alkalinity. This bath measures 11.5pH with paper pH strips, which is quite high, and is due mainly to the NaOH. There's a lot more Metol here than in Kodak D-19, and it may keep grain growth down while initiating developer sites. This formula sets a record for <b>A</b>scorbic <b>A</b>cid content in a developer. The Vitamin C produces a satisfying fizzing sound when dumped into the Drano/Washing Soda solution. No developing times or temperatures were given, only the guideline of a density of 2.5. You're on your own on how to get there. With all the developing agents and the high pH, you would expect that it be a highly energetic developer. And that may be just what it takes to get this emulsion to perform to its utmost. For the resulting holograms were extremely bright and low noise! The best tested so far. But the replay color is shifted from the He-Ne red, although it does replay at that wavelength, albeit with a bit of tilt. Developed in the above stew and bleached in PBQ, I got extremely good efficiency and signal to noise ratio! But since the replay color was not quite the same as the laser’s, something must be screwy with the gelatin of this emulsion. It is shrinking after processing, both with this developer and CWC2. A trick that I would use to retain original Bragg plane spacing with the Ilford emulsions having the BIPS<ref>Built-In Pre-Swell, so that the replay color was automatically shifted about 25-35 nanometers even when using a develop-rehalogenating bleach scheme, which should retain the recording fringe pattern spacing. To retain laser color fidelity this bloating agent had to be washed out <u>before</u> exposure. Nobody should be forced to handle things in the dark more than is necessary, especially since the emulsion could be damaged or fogged before shooting the hologram. Let's hope nobody else is brilliant enough to come up with that marketing scheme again! The problems it created! Why put something in that nobody really needed?</ref> ingredient would be to develop in a pyro-based developer and bleach with PBQ. When pyrogallol develops, it tans the gelatin surrounding the developing grain with its by-products. The gelatin is hardened while it is swollen with water, and it does not collapse as much as it would in a non-tanning developer. Comparing two holographic exposure series plates on Holotest, both developed to the same densities, one in PyroChrome developer and the other in the not-so-tanning CWC2, the same amount of developed silver got removed in the silver solvent 'Chrome bleach, but the higher structural integrity of the gelatin as a result of the tanning results in less shrinkage and not as green a color shift. The problem with this scheme of color control is that the plumping up of the emulsion is dependent on developed density. The tanning needs to compensate for the natural shrinkage of the gelatin. Usually with the Ilford material one of the exposures produced enough tanning action that the desired effect of real-time fringes could be observed. So there is a formula included with the BB instructions for a Pyrogallol based developer that I figured would be as energetic as their Vitamin C soup. <b>BB PYRO DEVELOPER</b> {| class="wikitable" border="1" |- | Part A || || | || 15 g || Pyrogallol | || 5 g || Metol | || 1 L || Water | Part B || || | || 30 g || Sodium Carbonate | || 7 g || Sodium Hydroxide | || 1 L || Water |} As is typical with the short-lived pyro concoctions, the two parts are mixed together immediately before use. The pyrogallol concentration is 50% higher than that of the original <i>Pyrochrome</i> recipe, and there is yet another boost to activity with the Metol, which may have a super-additive effect. I followed this developer with rehalogenating CWPBQ2, not with the dichromate based reversal bleach as recommended in the BB instruction sheet, because I wanted to overcome the shrink of the gelatin and not induce any more wavelength shifting to the green, as what would happen using the latter bleach. Development time with both of these developers was five minutes, with an ambient temperature of Chicago Spring of 72F. Keeping the development time constant and letting the exposure time determine the final density build up yields more easily repeatable results. Five minutes (a couple of good songs) is the maximum I am willing to wait for results. This developer gave the minimal amount of shrinkage, yielding real-time fringes on the kinematic holder, and a really nice signal to noise ratio. But I wasn’t satisfied with the shrinkage of the BB AA developer, so I tried another High Energy developer, Kodak D-8. (I only used 2’ development time as there was a danger of fogging.) The pH of this one is way up there with the other two, and with its high hydroquinone content it really builds up density! Figure Three shows all three developers’ results.<o:p></o:p></span></p> [[File:HCRGimage006.gif|right|BB 640 and 3 Developers, BB Pyro, Kodak D-8, and BB AA, all with CWPBQ2 Bleach. On the left the replay color is laser perfect, the middle an orangey-yellow, and the right a yellowy-green.]] == Slavich PFG-03M == When I finally received what I had been looking for I couldn't believe it; here in my hot little hands were samples of the famed Russian holographic technology. High efficiency, high signal to noise and of course the dreaded low sensitivity. But the quality of the hologram should be worth all the sacrifice. So I started with the classic CWC2, and it was barely OK, as evidenced in Figure Two. Conventional holographic wisdom (or is it lore?) that the Russian emulsions demanded colloidal development because of the super-fine grains. But I had previously tried the typical Western processing scheme on some Bulgarian Holographic Plates in the late ‘80’s. In the summer of 1982, Dr. V. C. Sainov brought a bunch of holographic plates that had been manufactured by the Bulgarian Academy of Sciences. They came in two flavors, HP-490 whose sensitivity peaked at 490 but continued on to at least 515 nm Argon green, and HP-650 plates with red sensitivity. He also had his own proprietary developer, FHP-3. We attempted to record holograms with these materials when experimenting with true color holography although these plates had been sitting in an attic for approximately seven years. The HP-650 was officially pronounced dead on arrival, but the HP-490 still had some life left in them. No fog was found when an unexposed plate was put into the developer, but there was some &quot;development&quot; in the form of shiny silver deposits around the edges of the plates where they had been in contact with some black packing paper. Perhaps some sulfur compounds used to make the paper black were to blame for reducing the silver bromide. Since we didn't have any of the recommended FHP-3 colloidal developer, we processed the plates in a developer - rehalogenating scheme using the CWC2 developer and CWPBQ2 bleach. The results were quite good, with fairly high efficiency and an incredibly high signal to noise ratio, at all wavelengths we tested, even down to 458 nm. But at what a price! The exposures were in the 20 to 80 <u>milli</u>Joules/cm2 range, about two orders of magnitude away from the Agfa plates, which were requiring 200 microJoules/cm2 for 8E56HD at 515 nm or 800 microJoules at the same wavelength for 8E75HD. You should expect to see dichromated gelatin performance at these exposure levels, which the material delivers with respect to signal to noise, but not so much in efficiency. The ten nanometer grains keep scatter to a minimum, but are not so efficient in capturing photons. Plus there are not enough of them to provide a very reflective Bragg layer. I had gotten comfortable with developing for only two minutes, but with these super slow plates four might be a better idea. It's only two extra minutes, but it can seem like an eternity.<ref>Let's have a contest to see who has the wildest things to do while wiling away the settling and developing times. What is on <u>your</u> mind?</ref> So it didn’t seem to unusual to process this way. But it seems that the GP2 formula is necessary for the best results on PFG-03M as of this writing. The first that I had ever heard of it was on a mimeographed sheet handed out by Nick Phillips at the 1982 ISDH.<ref>I still have it in my permanent collection! The earliest publication that I have of the formula in my collection is Ostrovski,...</ref> Even that scholarly tome, Hans Bjelkhagen’s book, gives the formula but does not state its origins. The rule is not to agitate in this bath. So I just put the plate in a photographic film developing tank (without the reel!) and closed the lid, sitting my trusty Gra-Lab timer (the backwards going clock) for 15 minutes and let it simmer. The instruction sheet says immersion of 10 to 15 minutes, and figuring that the Helium Neon holographer needs all the speed out of the material, I used 15 minutes. Even with the long development time, I needed 80 second exposures! (HD needs only 5&quot;!) I used Edwal non-hardening fixer as I had some mixed up for black and white photographic printing. The Slavich fixer formulation is rather simple, just Sodium Thiosulfate with some Potassium Metabisulfite as a preservative. I didn't have any of the latter on hand, and wasn't in a mood to order some. This worked just peachy. After drying the image looked very bright and clean. The plate itself was not transparent like the others processed in the develop bleach regime, but it was of that reddish-brown color indicative of colloidal development. This added to the signal to noise ratio. And it was capable of real-time fringes, as the developed layer color had only fairly low density at 633 nm. When flipping over the plate and illuminating the emulsion side to observe the real image, the image color looks a little chirped; it is not a red color, but kind of pink. So it appears that if the final holographic result is to be displayed pseudoscopically, it should be exposed with its emulsion away from the object. (Maybe this is an artifact of not using their fixer?) Because I am of the old hard core school of develop and bleach, I tried Kodak D-8 as the developer. But this doesn't look so hot, so it’s not illustrated. === The Pre-hardener Problem === The idea of pre-hardening the plates doesn't seem like such a good idea to me. The only photographic process that comes to mind that requires such a step was the old Ektachrome E-4 color process. The untreated film was not capable of withstanding the high temperatures necessary for short process times, so this pre-developer step was added. But what really makes me queasy are two of the constituents of the solution; Formaldehyde and potassium bromide. Formalin solution is not easy to come by; even just having the stuff in a darkroom doesn't sit right with me. It belongs in an embalming room<ref>I got mine from my undertaker buddies.</ref> Perhaps in Eastern Europe this stuff isn't considered that dangerous, but here you will be paying a bundle in Hazardous Material Shipping Charges! The other component in this bath that raises one of my eyebrows is the potassium bromide. I know from experience that solutions of bromide can <u>erase</u> a latent image!<ref>My own paper, Recycling of Holographic Plates... Sorry for the sketch footnotes! Maybe when this gets published for real!</ref> Although it is a minute amount, anything that slows these plates down should be avoided. But just for the sake of you, dear readers, I got ahold of some Formalin solution and made up a batch of this toxic waste. It appears to be necessary for the -03 emulsions. [[File:HCRGimage008.gif|right|The Ultra-Fine Grained Crew. It seems like a tie between the BB 640 developed with Pyro and bleached in PBQ and the PFG-03M and its GP2 colloidal developer.]] == Conclusions == Figure Five shows the full-plate holograms using the best exposure and developer combination based on the above trial and error exposure tests, 200 μJ/cm² for the larger grained Holotest and PFG-01, 3.2 mJ/cm² for the finer grained. They are illuminated on the flip or pseudoscopic side, so they look like bite-sized tasty morsels of that Belgian treat. The chirped aspect of the PFG-03M is visible from this, the emulsion side, but it looks narrow-band red through the glass. Go figure. We are looking at the emulsion side of this batch in this picture because I painted the glass side with black spray paint to give a better idea of the signal to noise of the emulsion. They were photographed against a Kodak 18% Gray Card to give some idea of relative diffraction efficiency. [[File:HCRGimage010.gif|right]] === Pricing === This is where it gets mind-boggling. One would think that the new kids on the block would try to not repeat the mistake of Agfa and charge an arm and a leg, but they do. Agfa got caught up in an inflationary spiral; the plates weren't selling, so they had to charge more. And then less people bought, so they charged even more. I remember when the HD series came out around 1980 and 4&quot; by 5&quot;'s were only about $2. At the end, they were $8, which is out of sync with the rest of the cost of living price increases. So I hope that this Holographic Consumer Report will help others spend their hard-earned dough wisely! <references /> aka The Home &amp; Studio of E. Wesly + Sons Names withheld to protect the guilty! It never failed to amaze me that those slick black boxes were made by Empak, in a suburb of Minneapolis, Minnesota, USA, shipped across the ocean, filled with the Lippmann emulsions in Belgium and back here again. I wonder how much that added to the price of the plates. Built-In Pre-Swell, so that the replay color was automatically shifted about 25-35 nanometers even when using a develop-rehalogenating bleach scheme, which should retain the recording fringe pattern spacing. To retain laser color fidelity this bloating agent had to be washed out <u>before</u> exposure. Nobody should be forced to handle things in the dark more than is necessary, especially since the emulsion could be damaged or fogged before shooting the hologram. Let's hope nobody else is brilliant enough to come up with that marketing scheme again! The problems it created! Why put something in that nobody really needed? Let's have a contest to see who has the wildest things to do while wiling away the settling and developing times. What is on <u>your</u> mind? I got mine from my undertaker buddies. [1] See for example, Zone System Manual, Ansel Adams, the negative, etc. [2] Private conversation, circa 1983. [3] Tell the tales of woe of the instruction sheets, including how worthless the Agfa ones were. Holographic paper collectors. [4] I still have it in my permanent collection! The earliest publication that I have of the formula in my collection is Ostrovski,... [5] My own paper, Recycling of Holographic Plates... Sorry for the sketch footnotes! Maybe when this gets published for real! bcdc59a5f073a36b5a159255222cebe83c71c245 2329 2327 2014-01-01T17:52:43Z Jsfisher 1 wikitext text/x-wiki = Silver Halide Holograpic Recording Materials 2000 = ''''M³ Visual Research Laboratory''''<ref>aka The Home & Studio of E. Wesly + Sons</ref>, as a service to the holographic community, is proud to present a <b>Consumer Report</b> on the state of the art of silver halide holographic recording materials. In the wake of the demise of Agfa's Holotest line up there is a real need for a suitable substitute, hopefully one that is brighter, less noisy, and less expensive. My Artist-Photographer Zone System<ref>See for example, Zone System Manual, Ansel Adams, the negative, etc.</ref> training compels me to carry out these tests, as understanding the materials results in more control in realizing the final result. As Ruben Nunez has said,<ref>Private conversation, circa 1983.</ref> we <u>need</u> a <i>Minister of Brightness</i>. I myself am curious as to what is up with these new products. However, I do not have much faith in literature published by manufacturers, or reports of other holographers who do not test other products side by side, or their technique which may be sloppier than mine. To be really fair, rigorous testing needs to be done, which is usually too boring to be undertaken by the typical holographer. We purchased samples of five different red-sensitive holographic recording materials: HRT BB-640, two flavors of Slavich plates, PFG-01 and PFG-O3M, plus some Chinese plates from Control Optics. All were of the same 63 by 63 mm or 2 1/2&quot; squares coated on glass, except for the Chinese plates, which were delivered as a sample package of four 4&quot; by 5&quot; glass plates. Two different sources were used to procure the Russian plates, yet they both bungled the job.<ref>Names withheld to protect the guilty!</ref> I wanted some PFG-03M plates, the ones that are legendary for ultra-fine grain, in the vicinity of 10 nanometers. From the one I received PFG-03<b><u>C</u> </b>plates, which is the true color or panchromatic emulsion. But it nevertheless has the teeny grains, so I thought I was happy. Until I opened the box! There were only 20, not 30 in it! From the other source I got another box of PFG-01 instead of PFG-03M. Although I had asked for them over the phone with a verbal description, I guess I had to be more precise with the exact alphanumeric code to avoid confusion. <u>Russian Plate Scorecard:</u> So I ended up with twice as many PFG-01 plates that I had wanted, no PFG-03M which I wanted most desperately, and something I didn't necessarily want, PFG-03C. I was introduced to the field of holography over twenty years ago at a photography teachers convention, wherein TJ*** not only showed some Russian holograms but also made a couple of holograms in front of a group of people. A day that changed my life! And he showed off some Russian holograms. It is hard to believe that now I can have my own Russian holo plates. <b>PACKAGING:</b> The Slavich plates are packed in cute little plastic boxes, not unlike the familiar Empak ones that the Agfa products came in. But they were not all that well-molded, and were difficult to open, which is what it should be, to avoid accidents, but were even harder to close properly, and sometimes gave the feeling that the job was not done well enough to be light-tight. <i>Cardboard</i> is the word for BB-640 plates' packaging and shame on you. There is a triple box made out of heavy card stock, with a black plastic bag sealing the plates inside from humidity. The plates are stacked inside the light tight baggy, with cardboard interleavings. Tacky, tacky, tacky! I haven't seen any scratches yet, but then I've only shot only a few. I transferred them to a traditional Empak box emptied of its Agfa plates.<ref>It never failed to amaze me that those slick black boxes were made by Empak, in a suburb of Minneapolis, Minnesota, USA, shipped across the ocean, filled with the Lippmann emulsions in Belgium and back here again. I wonder how much that added to the price of the plates.</ref> The four Chinese 4&quot; by 5&quot; plates were simply wrapped in black paper and thrown in a box with styrofoam peanuts. To separate them small dots of paper were folded over some of the edges. Admittedly these were a sample package, but it doesn't inspire confidence in the product by the cavalier manner that they were shipped. How could you use a scratched plate in an art piece? As a standard of comparison, some plates from my secret stash, an unopened box of Agfa Holotest 8E75HD, batch # 591304, expiration date of 02/00, were exposed and processed alongside the rest. <b><u>PHASE ONE: ON AN EQUAL FOOTING</u></b> To start off with all things being equal, plates from all boxes were exposed with a series of exposures and developed in the developer that has been the household standard for so long, <b>CWC2</b>, with an immersion time of two minutes. (For more details about the process, see the <b>Handout, CWC2</b>.) This developer bleach combination gets a high brightness out of the Holotest material, signal to noise is directly related developed density, and there is no distortion of the fringes, as the plate can be replaced onto the object and real-time fringes can be observed! The hologram casts a very dark shadow on the object as it steals reference beam light. The CWC2 process and Holotest materials are as peaked as perfectly as possible for this application. It used to be the standard of the industry. Let us see if the new materials can beat it. For this phase of testing the qualities that the holographic samples are judged on are brightness, signal to noise ratio, and replay wavelength fidelity. The last aspect is important for making copies of reflection holograms, with either contact or separated geometries. Sometimes a different replay color is desired for display purposes, but shrinkage to shorter wavelength replay shows that the material is not replaying the recorded fringe pattern as faithfully as it should. <b>BLEACHING:</b> I know that this will upset many of you right off, but the bleach that I used for these tests was the dreaded <b>CWPBQ2</b>, for a variety of reasons. First off, I paid $26.10 for a half pound of it 15 years ago, and being a holographic cheapskate I want to use it up. But most importantly, when it is used with the CWC2 developer, it yields a hologram whose fringes are distortion free, as evidenced by brightest replay at the recording angle and the possibility of producing real-time interferometric fringes when the plate is replaced exactly on the object holder. Using the two nested trays method contains the obnoxious odor. Most of the other rehalogenating bleaches that I have tested (see the <b>Handout, ROUNDUP '90</b>) work pretty much the same, except the Ferric EDTA ones usually exhibit noticeable shrinkage, and the Copper Sulfate prints out like crazy. Just pick your poison. I didn’t have time to investigate solvent bleaches, to induce shrinkage to shorter replay wavelengths. === Exposure Methodology === The tried and true <i>Standard Object</i> was dusted off for the exposure testing series, which is an antique waffle iron mold sprayed with <b>Krylon #1401 Bright Silver</b>. This paint uses aluminum flakes for its pigment, which in addition to being highly reflective, preserves polarization vectors. The waffle iron is a not too deep object, with a homogenous background. A series of exposures can be made on one plate with each quadrant having an identical scene. Plus when viewed pseudoscopically it looks like the waffle itself! Three ball bearings support the plate so it doesn’t rock. A bar prevents it from sliding down and blocks light from entering the edge of the plate. The iron mold is supported in a kind of goal post arrangement so that it can be tilted to give a decent reference angle, which was about 30 degrees from the normal in this case to prevent the shadows of the waffle texture from getting too long. Figure One shows the rig with a processed plate replaced back into its exposed position generating real-time interferometric fringes, demonstrating the stability of the kinematic device. [[File:HCRGimage002.gif|right]Kinematic Plateholding Object, demonstrating real-time holographic fringes on a well-processed plate.] The <b>isolation system</b> was my unpatented <b>BIG BEAM</b> as featured in a variety of articles. Photons supplied by a Melles Griot LHP 171 7 mW He-Ne, spatially filtered by Jodon. Incident flux was measured by a borrowed Newport 820 at 40 microWatts per square centimeter. One quarter of a cardboard square the same size as the plates was cut out, so that &frac34; of the plate was blocked while one quadrant was exposed. Exposure doses varied with the material, with the Agfa and PFG-01 receiving 50 microJoules per cm² minimally and going on up to 3200 microJoules per cm² for the tiny grainers. The exposure doses are given on a label attached to the center of the plate in most of the following photos. Exposure times varied from 1.25” for 50 μJ/cm² on up to 80” for the longest 3.2 millJoules per cm². == Results == Figure Two shows the preliminary holograms. The standard of comparison was the Holotest, and this batch exhibited behavior like all the prior ones: a threshold of image visibility at about 50 μJ/cm2, increasing brightness until that peaks at around 200 μJ/cm2, and at exposure doses beyond that the plate gets very noisy. [[File:HCRGimage004.gif|right|All samples developed in CWC2 and bleached in CWPBQ2. Unpainted backs, holograms laid on a piece of black velvet.]] The PFG-01 is claimed to be a drop-in replacement for the above. When exposed and processed alongside the Agfa, it is a close match in brightness but the obvious winner in signal to noise.It also could produce real time fringes when positioned on the object. I had heard that the HRT BB-640 would need more exposure than the Agfa, so I started with 200 μJ/cm² and worked up to 1600 μJ/cm² or 1.6 milliJoules/cm². The color was orangey, brightness not as good as the others, but this was the lowest noise so far. Hopefully using its own developer will improve the situation, as it is so nice to see almost transparent glass in the darkest areas, as opposed to the veiling haze of scatter with the two above. I gave the same exposure series to the Control Optics plates, but they shrank into the green! Their instructions say to use a modified CWC2 developer, which is just the usual formulation <i>sans</i> urea. This makes sense since the urea is a penetrant, a gelatin softener, and it let the layer shrink to the green. We never got around to seeing what its deletion does because the plates were destroyed while cutting the 4” by 5”s down to 2 &frac12;” squares. The glass was thinner than the usual 1.5 mm of Agfa. Otherwise the brightness and noise were not unlike the BB-640. The Slavich PFG-03C also suffered from serious shrinkage. (Not shown.) Its instruction sheet mentions a Hardener step, which would have been implemented in the next round of testing, if it were not noticed that the material had arrived fogged. There was a gross white haze around the edges of the hologram. When an unexposed plate was plopped into the developer, it almost uniformly darkened. After a few phone calls the situation was straightened out and I received a nice fresh box of Slavich PFG-03M, which was what I had desired all along. The results were not all that bright when done in this manner. At the end of Round One of Phase One it seems that the PFG-01 is truly a drop-in replacement for Agfa Holotest 8E75HD. Its peak brightness comes at a lower density, with slightly less noise, maybe because as Ilford had always claimed Agfa had quite a few huge (relatively) &quot;rogue grains&quot; floating around which may have been the major contributing factor to noise as well as density. It is surprising that its sensitivity is pretty much exactly the same as Agfa's! The Slavich chemists had certainly done a good job of reverse engineering the Agfa plates. The other materials do not seem to be peaked with this processing scheme. The shifted replay color and not all that dazzling efficiency (albeit low noise!) points out that we should check out the instruction sheets<ref>Tell the tales of woe of the instruction sheets, including how worthless the Agfa ones were. Holographic paper collectors.</ref> for these materials to see what the manufacturers' suggest. <b><u>PHASE TWO: A PROCESSING SCHEME OF THEIR OWN</u></b> What a surprise! Following the manufacturers’ recommendations improved the quality of the holograms! I opted to optimize the German material, HRT BB-640 next. Of all the materials it looked the cleanest, and with CWC2 had better sensitivity than either the Chinese plates or Slavich PFG-03C or M. So I mixed up a batch of <b>BBAA DEVELOPER</b> {| class="wikitable" border="1" |- | 70 g || Sodium Carbonate |- | 15 g || Sodium Hydroxide |- | 4 g || Metol |- | 26 g || Ascorbic Acid |- | 1 L || Water |} The Sodium Carbonate and Hydroxide are there to provide the necessary alkalinity. This bath measures 11.5pH with paper pH strips, which is quite high, and is due mainly to the NaOH. There's a lot more Metol here than in Kodak D-19, and it may keep grain growth down while initiating developer sites. This formula sets a record for <b>A</b>scorbic <b>A</b>cid content in a developer. The Vitamin C produces a satisfying fizzing sound when dumped into the Drano/Washing Soda solution. No developing times or temperatures were given, only the guideline of a density of 2.5. You're on your own on how to get there. With all the developing agents and the high pH, you would expect that it be a highly energetic developer. And that may be just what it takes to get this emulsion to perform to its utmost. For the resulting holograms were extremely bright and low noise! The best tested so far. But the replay color is shifted from the He-Ne red, although it does replay at that wavelength, albeit with a bit of tilt. Developed in the above stew and bleached in PBQ, I got extremely good efficiency and signal to noise ratio! But since the replay color was not quite the same as the laser’s, something must be screwy with the gelatin of this emulsion. It is shrinking after processing, both with this developer and CWC2. A trick that I would use to retain original Bragg plane spacing with the Ilford emulsions having the BIPS<ref>Built-In Pre-Swell, so that the replay color was automatically shifted about 25-35 nanometers even when using a develop-rehalogenating bleach scheme, which should retain the recording fringe pattern spacing. To retain laser color fidelity this bloating agent had to be washed out <u>before</u> exposure. Nobody should be forced to handle things in the dark more than is necessary, especially since the emulsion could be damaged or fogged before shooting the hologram. Let's hope nobody else is brilliant enough to come up with that marketing scheme again! The problems it created! Why put something in that nobody really needed?</ref> ingredient would be to develop in a pyro-based developer and bleach with PBQ. When pyrogallol develops, it tans the gelatin surrounding the developing grain with its by-products. The gelatin is hardened while it is swollen with water, and it does not collapse as much as it would in a non-tanning developer. Comparing two holographic exposure series plates on Holotest, both developed to the same densities, one in PyroChrome developer and the other in the not-so-tanning CWC2, the same amount of developed silver got removed in the silver solvent 'Chrome bleach, but the higher structural integrity of the gelatin as a result of the tanning results in less shrinkage and not as green a color shift. The problem with this scheme of color control is that the plumping up of the emulsion is dependent on developed density. The tanning needs to compensate for the natural shrinkage of the gelatin. Usually with the Ilford material one of the exposures produced enough tanning action that the desired effect of real-time fringes could be observed. So there is a formula included with the BB instructions for a Pyrogallol based developer that I figured would be as energetic as their Vitamin C soup. <b>BB PYRO DEVELOPER</b> {| class="wikitable" border="1" |- | Part A || || |- | || 15 g || Pyrogallol |- | || 5 g || Metol |- | || 1 L || Water |- | Part B || || |- | || 30 g || Sodium Carbonate |- | || 7 g || Sodium Hydroxide |- | || 1 L || Water |} As is typical with the short-lived pyro concoctions, the two parts are mixed together immediately before use. The pyrogallol concentration is 50% higher than that of the original <i>Pyrochrome</i> recipe, and there is yet another boost to activity with the Metol, which may have a super-additive effect. I followed this developer with rehalogenating CWPBQ2, not with the dichromate based reversal bleach as recommended in the BB instruction sheet, because I wanted to overcome the shrink of the gelatin and not induce any more wavelength shifting to the green, as what would happen using the latter bleach. Development time with both of these developers was five minutes, with an ambient temperature of Chicago Spring of 72F. Keeping the development time constant and letting the exposure time determine the final density build up yields more easily repeatable results. Five minutes (a couple of good songs) is the maximum I am willing to wait for results. This developer gave the minimal amount of shrinkage, yielding real-time fringes on the kinematic holder, and a really nice signal to noise ratio. But I wasn’t satisfied with the shrinkage of the BB AA developer, so I tried another High Energy developer, Kodak D-8. (I only used 2’ development time as there was a danger of fogging.) The pH of this one is way up there with the other two, and with its high hydroquinone content it really builds up density! Figure Three shows all three developers’ results.<o:p></o:p></span></p> [[File:HCRGimage006.gif|right|BB 640 and 3 Developers, BB Pyro, Kodak D-8, and BB AA, all with CWPBQ2 Bleach. On the left the replay color is laser perfect, the middle an orangey-yellow, and the right a yellowy-green.]] == Slavich PFG-03M == When I finally received what I had been looking for I couldn't believe it; here in my hot little hands were samples of the famed Russian holographic technology. High efficiency, high signal to noise and of course the dreaded low sensitivity. But the quality of the hologram should be worth all the sacrifice. So I started with the classic CWC2, and it was barely OK, as evidenced in Figure Two. Conventional holographic wisdom (or is it lore?) that the Russian emulsions demanded colloidal development because of the super-fine grains. But I had previously tried the typical Western processing scheme on some Bulgarian Holographic Plates in the late ‘80’s. In the summer of 1982, Dr. V. C. Sainov brought a bunch of holographic plates that had been manufactured by the Bulgarian Academy of Sciences. They came in two flavors, HP-490 whose sensitivity peaked at 490 but continued on to at least 515 nm Argon green, and HP-650 plates with red sensitivity. He also had his own proprietary developer, FHP-3. We attempted to record holograms with these materials when experimenting with true color holography although these plates had been sitting in an attic for approximately seven years. The HP-650 was officially pronounced dead on arrival, but the HP-490 still had some life left in them. No fog was found when an unexposed plate was put into the developer, but there was some &quot;development&quot; in the form of shiny silver deposits around the edges of the plates where they had been in contact with some black packing paper. Perhaps some sulfur compounds used to make the paper black were to blame for reducing the silver bromide. Since we didn't have any of the recommended FHP-3 colloidal developer, we processed the plates in a developer - rehalogenating scheme using the CWC2 developer and CWPBQ2 bleach. The results were quite good, with fairly high efficiency and an incredibly high signal to noise ratio, at all wavelengths we tested, even down to 458 nm. But at what a price! The exposures were in the 20 to 80 <u>milli</u>Joules/cm2 range, about two orders of magnitude away from the Agfa plates, which were requiring 200 microJoules/cm2 for 8E56HD at 515 nm or 800 microJoules at the same wavelength for 8E75HD. You should expect to see dichromated gelatin performance at these exposure levels, which the material delivers with respect to signal to noise, but not so much in efficiency. The ten nanometer grains keep scatter to a minimum, but are not so efficient in capturing photons. Plus there are not enough of them to provide a very reflective Bragg layer. I had gotten comfortable with developing for only two minutes, but with these super slow plates four might be a better idea. It's only two extra minutes, but it can seem like an eternity.<ref>Let's have a contest to see who has the wildest things to do while wiling away the settling and developing times. What is on <u>your</u> mind?</ref> So it didn’t seem to unusual to process this way. But it seems that the GP2 formula is necessary for the best results on PFG-03M as of this writing. The first that I had ever heard of it was on a mimeographed sheet handed out by Nick Phillips at the 1982 ISDH.<ref>I still have it in my permanent collection! The earliest publication that I have of the formula in my collection is Ostrovski,...</ref> Even that scholarly tome, Hans Bjelkhagen’s book, gives the formula but does not state its origins. The rule is not to agitate in this bath. So I just put the plate in a photographic film developing tank (without the reel!) and closed the lid, sitting my trusty Gra-Lab timer (the backwards going clock) for 15 minutes and let it simmer. The instruction sheet says immersion of 10 to 15 minutes, and figuring that the Helium Neon holographer needs all the speed out of the material, I used 15 minutes. Even with the long development time, I needed 80 second exposures! (HD needs only 5&quot;!) I used Edwal non-hardening fixer as I had some mixed up for black and white photographic printing. The Slavich fixer formulation is rather simple, just Sodium Thiosulfate with some Potassium Metabisulfite as a preservative. I didn't have any of the latter on hand, and wasn't in a mood to order some. This worked just peachy. After drying the image looked very bright and clean. The plate itself was not transparent like the others processed in the develop bleach regime, but it was of that reddish-brown color indicative of colloidal development. This added to the signal to noise ratio. And it was capable of real-time fringes, as the developed layer color had only fairly low density at 633 nm. When flipping over the plate and illuminating the emulsion side to observe the real image, the image color looks a little chirped; it is not a red color, but kind of pink. So it appears that if the final holographic result is to be displayed pseudoscopically, it should be exposed with its emulsion away from the object. (Maybe this is an artifact of not using their fixer?) Because I am of the old hard core school of develop and bleach, I tried Kodak D-8 as the developer. But this doesn't look so hot, so it’s not illustrated. === The Pre-hardener Problem === The idea of pre-hardening the plates doesn't seem like such a good idea to me. The only photographic process that comes to mind that requires such a step was the old Ektachrome E-4 color process. The untreated film was not capable of withstanding the high temperatures necessary for short process times, so this pre-developer step was added. But what really makes me queasy are two of the constituents of the solution; Formaldehyde and potassium bromide. Formalin solution is not easy to come by; even just having the stuff in a darkroom doesn't sit right with me. It belongs in an embalming room<ref>I got mine from my undertaker buddies.</ref> Perhaps in Eastern Europe this stuff isn't considered that dangerous, but here you will be paying a bundle in Hazardous Material Shipping Charges! The other component in this bath that raises one of my eyebrows is the potassium bromide. I know from experience that solutions of bromide can <u>erase</u> a latent image!<ref>My own paper, Recycling of Holographic Plates... Sorry for the sketch footnotes! Maybe when this gets published for real!</ref> Although it is a minute amount, anything that slows these plates down should be avoided. But just for the sake of you, dear readers, I got a hold of some Formalin solution and made up a batch of this toxic waste. It appears to be necessary for the -03 emulsions. [[File:HCRGimage008.gif|right|The Ultra-Fine Grained Crew. It seems like a tie between the BB 640 developed with Pyro and bleached in PBQ and the PFG-03M and its GP2 colloidal developer.]] == Conclusions == [[File:HCRGimage010.gif|right]] Figure Five shows the full-plate holograms using the best exposure and developer combination based on the above trial and error exposure tests, 200 μJ/cm² for the larger grained Holotest and PFG-01, 3.2 mJ/cm² for the finer grained. They are illuminated on the flip or pseudoscopic side, so they look like bite-sized tasty morsels of that Belgian treat. The chirped aspect of the PFG-03M is visible from this, the emulsion side, but it looks narrow-band red through the glass. Go figure. We are looking at the emulsion side of this batch in this picture because I painted the glass side with black spray paint to give a better idea of the signal to noise of the emulsion. They were photographed against a Kodak 18% Gray Card to give some idea of relative diffraction efficiency. === Pricing === This is where it gets mind-boggling. One would think that the new kids on the block would try to not repeat the mistake of Agfa and charge an arm and a leg, but they do. Agfa got caught up in an inflationary spiral; the plates weren't selling, so they had to charge more. And then less people bought, so they charged even more. I remember when the HD series came out around 1980 and 4&quot; by 5&quot;'s were only about $2. At the end, they were $8, which is out of sync with the rest of the cost of living price increases. So I hope that this Holographic Consumer Report will help others spend their hard-earned dough wisely! == Notes and References == <references /> 8694d38125d31621e1b5b7a0f9d1bd36e242c79b 2330 2329 2014-01-01T17:59:04Z Jsfisher 1 wikitext text/x-wiki '''<big>Silver Halide Holograpic Recording Materials 2000</big>''' ''''M³ Visual Research Laboratory''''<ref>aka The Home & Studio of E. Wesly + Sons</ref>, as a service to the holographic community, is proud to present a <b>Consumer Report</b> on the state of the art of silver halide holographic recording materials. In the wake of the demise of Agfa's Holotest line up there is a real need for a suitable substitute, hopefully one that is brighter, less noisy, and less expensive. My Artist-Photographer Zone System<ref>See for example, Zone System Manual, Ansel Adams, the negative, etc.</ref> training compels me to carry out these tests, as understanding the materials results in more control in realizing the final result. As Ruben Nunez has said,<ref>Private conversation, circa 1983.</ref> we <u>need</u> a <i>Minister of Brightness</i>. I myself am curious as to what is up with these new products. However, I do not have much faith in literature published by manufacturers, or reports of other holographers who do not test other products side by side, or their technique which may be sloppier than mine. To be really fair, rigorous testing needs to be done, which is usually too boring to be undertaken by the typical holographer. We purchased samples of five different red-sensitive holographic recording materials: HRT BB-640, two flavors of Slavich plates, PFG-01 and PFG-O3M, plus some Chinese plates from Control Optics. All were of the same 63 by 63 mm or 2 1/2&quot; squares coated on glass, except for the Chinese plates, which were delivered as a sample package of four 4&quot; by 5&quot; glass plates. Two different sources were used to procure the Russian plates, yet they both bungled the job.<ref>Names withheld to protect the guilty!</ref> I wanted some PFG-03M plates, the ones that are legendary for ultra-fine grain, in the vicinity of 10 nanometers. From the one I received PFG-03<b><u>C</u> </b>plates, which is the true color or panchromatic emulsion. But it nevertheless has the teeny grains, so I thought I was happy. Until I opened the box! There were only 20, not 30 in it! From the other source I got another box of PFG-01 instead of PFG-03M. Although I had asked for them over the phone with a verbal description, I guess I had to be more precise with the exact alphanumeric code to avoid confusion. <u>Russian Plate Scorecard:</u> So I ended up with twice as many PFG-01 plates that I had wanted, no PFG-03M which I wanted most desperately, and something I didn't necessarily want, PFG-03C. I was introduced to the field of holography over twenty years ago at a photography teachers convention, wherein TJ*** not only showed some Russian holograms but also made a couple of holograms in front of a group of people. A day that changed my life! And he showed off some Russian holograms. It is hard to believe that now I can have my own Russian holo plates. <b>PACKAGING:</b> The Slavich plates are packed in cute little plastic boxes, not unlike the familiar Empak ones that the Agfa products came in. But they were not all that well-molded, and were difficult to open, which is what it should be, to avoid accidents, but were even harder to close properly, and sometimes gave the feeling that the job was not done well enough to be light-tight. <i>Cardboard</i> is the word for BB-640 plates' packaging and shame on you. There is a triple box made out of heavy card stock, with a black plastic bag sealing the plates inside from humidity. The plates are stacked inside the light tight baggy, with cardboard interleavings. Tacky, tacky, tacky! I haven't seen any scratches yet, but then I've only shot only a few. I transferred them to a traditional Empak box emptied of its Agfa plates.<ref>It never failed to amaze me that those slick black boxes were made by Empak, in a suburb of Minneapolis, Minnesota, USA, shipped across the ocean, filled with the Lippmann emulsions in Belgium and back here again. I wonder how much that added to the price of the plates.</ref> The four Chinese 4&quot; by 5&quot; plates were simply wrapped in black paper and thrown in a box with styrofoam peanuts. To separate them small dots of paper were folded over some of the edges. Admittedly these were a sample package, but it doesn't inspire confidence in the product by the cavalier manner that they were shipped. How could you use a scratched plate in an art piece? As a standard of comparison, some plates from my secret stash, an unopened box of Agfa Holotest 8E75HD, batch # 591304, expiration date of 02/00, were exposed and processed alongside the rest. <b><u>PHASE ONE: ON AN EQUAL FOOTING</u></b> To start off with all things being equal, plates from all boxes were exposed with a series of exposures and developed in the developer that has been the household standard for so long, <b>CWC2</b>, with an immersion time of two minutes. (For more details about the process, see the <b>Handout, CWC2</b>.) This developer bleach combination gets a high brightness out of the Holotest material, signal to noise is directly related developed density, and there is no distortion of the fringes, as the plate can be replaced onto the object and real-time fringes can be observed! The hologram casts a very dark shadow on the object as it steals reference beam light. The CWC2 process and Holotest materials are as peaked as perfectly as possible for this application. It used to be the standard of the industry. Let us see if the new materials can beat it. For this phase of testing the qualities that the holographic samples are judged on are brightness, signal to noise ratio, and replay wavelength fidelity. The last aspect is important for making copies of reflection holograms, with either contact or separated geometries. Sometimes a different replay color is desired for display purposes, but shrinkage to shorter wavelength replay shows that the material is not replaying the recorded fringe pattern as faithfully as it should. <b>BLEACHING:</b> I know that this will upset many of you right off, but the bleach that I used for these tests was the dreaded <b>CWPBQ2</b>, for a variety of reasons. First off, I paid $26.10 for a half pound of it 15 years ago, and being a holographic cheapskate I want to use it up. But most importantly, when it is used with the CWC2 developer, it yields a hologram whose fringes are distortion free, as evidenced by brightest replay at the recording angle and the possibility of producing real-time interferometric fringes when the plate is replaced exactly on the object holder. Using the two nested trays method contains the obnoxious odor. Most of the other rehalogenating bleaches that I have tested (see the <b>Handout, ROUNDUP '90</b>) work pretty much the same, except the Ferric EDTA ones usually exhibit noticeable shrinkage, and the Copper Sulfate prints out like crazy. Just pick your poison. I didn’t have time to investigate solvent bleaches, to induce shrinkage to shorter replay wavelengths. === Exposure Methodology === The tried and true <i>Standard Object</i> was dusted off for the exposure testing series, which is an antique waffle iron mold sprayed with <b>Krylon #1401 Bright Silver</b>. This paint uses aluminum flakes for its pigment, which in addition to being highly reflective, preserves polarization vectors. The waffle iron is a not too deep object, with a homogenous background. A series of exposures can be made on one plate with each quadrant having an identical scene. Plus when viewed pseudoscopically it looks like the waffle itself! Three ball bearings support the plate so it doesn’t rock. A bar prevents it from sliding down and blocks light from entering the edge of the plate. The iron mold is supported in a kind of goal post arrangement so that it can be tilted to give a decent reference angle, which was about 30 degrees from the normal in this case to prevent the shadows of the waffle texture from getting too long. Figure One shows the rig with a processed plate replaced back into its exposed position generating real-time interferometric fringes, demonstrating the stability of the kinematic device. [[File:HCRGimage002.gif|right]Kinematic Plateholding Object, demonstrating real-time holographic fringes on a well-processed plate.] The <b>isolation system</b> was my unpatented <b>BIG BEAM</b> as featured in a variety of articles. Photons supplied by a Melles Griot LHP 171 7 mW He-Ne, spatially filtered by Jodon. Incident flux was measured by a borrowed Newport 820 at 40 microWatts per square centimeter. One quarter of a cardboard square the same size as the plates was cut out, so that &frac34; of the plate was blocked while one quadrant was exposed. Exposure doses varied with the material, with the Agfa and PFG-01 receiving 50 microJoules per cm² minimally and going on up to 3200 microJoules per cm² for the tiny grainers. The exposure doses are given on a label attached to the center of the plate in most of the following photos. Exposure times varied from 1.25” for 50 μJ/cm² on up to 80” for the longest 3.2 millJoules per cm². == Results == Figure Two shows the preliminary holograms. The standard of comparison was the Holotest, and this batch exhibited behavior like all the prior ones: a threshold of image visibility at about 50 μJ/cm2, increasing brightness until that peaks at around 200 μJ/cm2, and at exposure doses beyond that the plate gets very noisy. [[File:HCRGimage004.gif|right|All samples developed in CWC2 and bleached in CWPBQ2. Unpainted backs, holograms laid on a piece of black velvet.]] The PFG-01 is claimed to be a drop-in replacement for the above. When exposed and processed alongside the Agfa, it is a close match in brightness but the obvious winner in signal to noise.It also could produce real time fringes when positioned on the object. I had heard that the HRT BB-640 would need more exposure than the Agfa, so I started with 200 μJ/cm² and worked up to 1600 μJ/cm² or 1.6 milliJoules/cm². The color was orangey, brightness not as good as the others, but this was the lowest noise so far. Hopefully using its own developer will improve the situation, as it is so nice to see almost transparent glass in the darkest areas, as opposed to the veiling haze of scatter with the two above. I gave the same exposure series to the Control Optics plates, but they shrank into the green! Their instructions say to use a modified CWC2 developer, which is just the usual formulation <i>sans</i> urea. This makes sense since the urea is a penetrant, a gelatin softener, and it let the layer shrink to the green. We never got around to seeing what its deletion does because the plates were destroyed while cutting the 4” by 5”s down to 2 &frac12;” squares. The glass was thinner than the usual 1.5 mm of Agfa. Otherwise the brightness and noise were not unlike the BB-640. The Slavich PFG-03C also suffered from serious shrinkage. (Not shown.) Its instruction sheet mentions a Hardener step, which would have been implemented in the next round of testing, if it were not noticed that the material had arrived fogged. There was a gross white haze around the edges of the hologram. When an unexposed plate was plopped into the developer, it almost uniformly darkened. After a few phone calls the situation was straightened out and I received a nice fresh box of Slavich PFG-03M, which was what I had desired all along. The results were not all that bright when done in this manner. At the end of Round One of Phase One it seems that the PFG-01 is truly a drop-in replacement for Agfa Holotest 8E75HD. Its peak brightness comes at a lower density, with slightly less noise, maybe because as Ilford had always claimed Agfa had quite a few huge (relatively) &quot;rogue grains&quot; floating around which may have been the major contributing factor to noise as well as density. It is surprising that its sensitivity is pretty much exactly the same as Agfa's! The Slavich chemists had certainly done a good job of reverse engineering the Agfa plates. The other materials do not seem to be peaked with this processing scheme. The shifted replay color and not all that dazzling efficiency (albeit low noise!) points out that we should check out the instruction sheets<ref>Tell the tales of woe of the instruction sheets, including how worthless the Agfa ones were. Holographic paper collectors.</ref> for these materials to see what the manufacturers' suggest. <b><u>PHASE TWO: A PROCESSING SCHEME OF THEIR OWN</u></b> What a surprise! Following the manufacturers’ recommendations improved the quality of the holograms! I opted to optimize the German material, HRT BB-640 next. Of all the materials it looked the cleanest, and with CWC2 had better sensitivity than either the Chinese plates or Slavich PFG-03C or M. So I mixed up a batch of <b>BBAA DEVELOPER</b> {| class="wikitable" border="1" |- | 70 g || Sodium Carbonate |- | 15 g || Sodium Hydroxide |- | 4 g || Metol |- | 26 g || Ascorbic Acid |- | 1 L || Water |} The Sodium Carbonate and Hydroxide are there to provide the necessary alkalinity. This bath measures 11.5pH with paper pH strips, which is quite high, and is due mainly to the NaOH. There's a lot more Metol here than in Kodak D-19, and it may keep grain growth down while initiating developer sites. This formula sets a record for <b>A</b>scorbic <b>A</b>cid content in a developer. The Vitamin C produces a satisfying fizzing sound when dumped into the Drano/Washing Soda solution. No developing times or temperatures were given, only the guideline of a density of 2.5. You're on your own on how to get there. With all the developing agents and the high pH, you would expect that it be a highly energetic developer. And that may be just what it takes to get this emulsion to perform to its utmost. For the resulting holograms were extremely bright and low noise! The best tested so far. But the replay color is shifted from the He-Ne red, although it does replay at that wavelength, albeit with a bit of tilt. Developed in the above stew and bleached in PBQ, I got extremely good efficiency and signal to noise ratio! But since the replay color was not quite the same as the laser’s, something must be screwy with the gelatin of this emulsion. It is shrinking after processing, both with this developer and CWC2. A trick that I would use to retain original Bragg plane spacing with the Ilford emulsions having the BIPS<ref>Built-In Pre-Swell, so that the replay color was automatically shifted about 25-35 nanometers even when using a develop-rehalogenating bleach scheme, which should retain the recording fringe pattern spacing. To retain laser color fidelity this bloating agent had to be washed out <u>before</u> exposure. Nobody should be forced to handle things in the dark more than is necessary, especially since the emulsion could be damaged or fogged before shooting the hologram. Let's hope nobody else is brilliant enough to come up with that marketing scheme again! The problems it created! Why put something in that nobody really needed?</ref> ingredient would be to develop in a pyro-based developer and bleach with PBQ. When pyrogallol develops, it tans the gelatin surrounding the developing grain with its by-products. The gelatin is hardened while it is swollen with water, and it does not collapse as much as it would in a non-tanning developer. Comparing two holographic exposure series plates on Holotest, both developed to the same densities, one in PyroChrome developer and the other in the not-so-tanning CWC2, the same amount of developed silver got removed in the silver solvent 'Chrome bleach, but the higher structural integrity of the gelatin as a result of the tanning results in less shrinkage and not as green a color shift. The problem with this scheme of color control is that the plumping up of the emulsion is dependent on developed density. The tanning needs to compensate for the natural shrinkage of the gelatin. Usually with the Ilford material one of the exposures produced enough tanning action that the desired effect of real-time fringes could be observed. So there is a formula included with the BB instructions for a Pyrogallol based developer that I figured would be as energetic as their Vitamin C soup. <b>BB PYRO DEVELOPER</b> {| class="wikitable" border="1" |- | Part A || || |- | || 15 g || Pyrogallol |- | || 5 g || Metol |- | || 1 L || Water |- | Part B || || |- | || 30 g || Sodium Carbonate |- | || 7 g || Sodium Hydroxide |- | || 1 L || Water |} As is typical with the short-lived pyro concoctions, the two parts are mixed together immediately before use. The pyrogallol concentration is 50% higher than that of the original <i>Pyrochrome</i> recipe, and there is yet another boost to activity with the Metol, which may have a super-additive effect. I followed this developer with rehalogenating CWPBQ2, not with the dichromate based reversal bleach as recommended in the BB instruction sheet, because I wanted to overcome the shrink of the gelatin and not induce any more wavelength shifting to the green, as what would happen using the latter bleach. Development time with both of these developers was five minutes, with an ambient temperature of Chicago Spring of 72F. Keeping the development time constant and letting the exposure time determine the final density build up yields more easily repeatable results. Five minutes (a couple of good songs) is the maximum I am willing to wait for results. [[File:HCRGimage006.gif|right|BB 640 and 3 Developers, BB Pyro, Kodak D-8, and BB AA, all with CWPBQ2 Bleach. On the left the replay color is laser perfect, the middle an orangey-yellow, and the right a yellowy-green.]] This developer gave the minimal amount of shrinkage, yielding real-time fringes on the kinematic holder, and a really nice signal to noise ratio. But I wasn’t satisfied with the shrinkage of the BB AA developer, so I tried another High Energy developer, Kodak D-8. (I only used 2’ development time as there was a danger of fogging.) The pH of this one is way up there with the other two, and with its high hydroquinone content it really builds up density! Figure Three shows all three developers’ results. == Slavich PFG-03M == When I finally received what I had been looking for I couldn't believe it; here in my hot little hands were samples of the famed Russian holographic technology. High efficiency, high signal to noise and of course the dreaded low sensitivity. But the quality of the hologram should be worth all the sacrifice. So I started with the classic CWC2, and it was barely OK, as evidenced in Figure Two. Conventional holographic wisdom (or is it lore?) that the Russian emulsions demanded colloidal development because of the super-fine grains. But I had previously tried the typical Western processing scheme on some Bulgarian Holographic Plates in the late ‘80’s. In the summer of 1982, Dr. V. C. Sainov brought a bunch of holographic plates that had been manufactured by the Bulgarian Academy of Sciences. They came in two flavors, HP-490 whose sensitivity peaked at 490 but continued on to at least 515 nm Argon green, and HP-650 plates with red sensitivity. He also had his own proprietary developer, FHP-3. We attempted to record holograms with these materials when experimenting with true color holography although these plates had been sitting in an attic for approximately seven years. The HP-650 was officially pronounced dead on arrival, but the HP-490 still had some life left in them. No fog was found when an unexposed plate was put into the developer, but there was some &quot;development&quot; in the form of shiny silver deposits around the edges of the plates where they had been in contact with some black packing paper. Perhaps some sulfur compounds used to make the paper black were to blame for reducing the silver bromide. Since we didn't have any of the recommended FHP-3 colloidal developer, we processed the plates in a developer - rehalogenating scheme using the CWC2 developer and CWPBQ2 bleach. The results were quite good, with fairly high efficiency and an incredibly high signal to noise ratio, at all wavelengths we tested, even down to 458 nm. But at what a price! The exposures were in the 20 to 80 <u>milli</u>Joules/cm2 range, about two orders of magnitude away from the Agfa plates, which were requiring 200 microJoules/cm2 for 8E56HD at 515 nm or 800 microJoules at the same wavelength for 8E75HD. You should expect to see dichromated gelatin performance at these exposure levels, which the material delivers with respect to signal to noise, but not so much in efficiency. The ten nanometer grains keep scatter to a minimum, but are not so efficient in capturing photons. Plus there are not enough of them to provide a very reflective Bragg layer. I had gotten comfortable with developing for only two minutes, but with these super slow plates four might be a better idea. It's only two extra minutes, but it can seem like an eternity.<ref>Let's have a contest to see who has the wildest things to do while wiling away the settling and developing times. What is on <u>your</u> mind?</ref> So it didn’t seem to unusual to process this way. But it seems that the GP2 formula is necessary for the best results on PFG-03M as of this writing. The first that I had ever heard of it was on a mimeographed sheet handed out by Nick Phillips at the 1982 ISDH.<ref>I still have it in my permanent collection! The earliest publication that I have of the formula in my collection is Ostrovski,...</ref> Even that scholarly tome, Hans Bjelkhagen’s book, gives the formula but does not state its origins. The rule is not to agitate in this bath. So I just put the plate in a photographic film developing tank (without the reel!) and closed the lid, sitting my trusty Gra-Lab timer (the backwards going clock) for 15 minutes and let it simmer. The instruction sheet says immersion of 10 to 15 minutes, and figuring that the Helium Neon holographer needs all the speed out of the material, I used 15 minutes. Even with the long development time, I needed 80 second exposures! (HD needs only 5&quot;!) I used Edwal non-hardening fixer as I had some mixed up for black and white photographic printing. The Slavich fixer formulation is rather simple, just Sodium Thiosulfate with some Potassium Metabisulfite as a preservative. I didn't have any of the latter on hand, and wasn't in a mood to order some. This worked just peachy. After drying the image looked very bright and clean. The plate itself was not transparent like the others processed in the develop bleach regime, but it was of that reddish-brown color indicative of colloidal development. This added to the signal to noise ratio. And it was capable of real-time fringes, as the developed layer color had only fairly low density at 633 nm. When flipping over the plate and illuminating the emulsion side to observe the real image, the image color looks a little chirped; it is not a red color, but kind of pink. So it appears that if the final holographic result is to be displayed pseudoscopically, it should be exposed with its emulsion away from the object. (Maybe this is an artifact of not using their fixer?) Because I am of the old hard core school of develop and bleach, I tried Kodak D-8 as the developer. But this doesn't look so hot, so it’s not illustrated. === The Pre-hardener Problem === The idea of pre-hardening the plates doesn't seem like such a good idea to me. The only photographic process that comes to mind that requires such a step was the old Ektachrome E-4 color process. The untreated film was not capable of withstanding the high temperatures necessary for short process times, so this pre-developer step was added. But what really makes me queasy are two of the constituents of the solution; Formaldehyde and potassium bromide. Formalin solution is not easy to come by; even just having the stuff in a darkroom doesn't sit right with me. It belongs in an embalming room<ref>I got mine from my undertaker buddies.</ref> Perhaps in Eastern Europe this stuff isn't considered that dangerous, but here you will be paying a bundle in Hazardous Material Shipping Charges! The other component in this bath that raises one of my eyebrows is the potassium bromide. I know from experience that solutions of bromide can <u>erase</u> a latent image!<ref>My own paper, Recycling of Holographic Plates... Sorry for the sketch footnotes! Maybe when this gets published for real!</ref> Although it is a minute amount, anything that slows these plates down should be avoided. But just for the sake of you, dear readers, I got a hold of some Formalin solution and made up a batch of this toxic waste. It appears to be necessary for the -03 emulsions. == Conclusions == [[File:HCRGimage008.gif|right|The Ultra-Fine Grained Crew. It seems like a tie between the BB 640 developed with Pyro and bleached in PBQ and the PFG-03M and its GP2 colloidal developer.]] Figure Five shows the full-plate holograms using the best exposure and developer combination based on the above trial and error exposure tests, 200 μJ/cm² for the larger grained Holotest and PFG-01, 3.2 mJ/cm² for the finer grained. They are illuminated on the flip or pseudoscopic side, so they look like bite-sized tasty morsels of that Belgian treat. The chirped aspect of the PFG-03M is visible from this, the emulsion side, but it looks narrow-band red through the glass. Go figure. We are looking at the emulsion side of this batch in this picture because I painted the glass side with black spray paint to give a better idea of the signal to noise of the emulsion. They were photographed against a Kodak 18% Gray Card to give some idea of relative diffraction efficiency. [[File:HCRGimage010.gif]] === Pricing === This is where it gets mind-boggling. One would think that the new kids on the block would try to not repeat the mistake of Agfa and charge an arm and a leg, but they do. Agfa got caught up in an inflationary spiral; the plates weren't selling, so they had to charge more. And then less people bought, so they charged even more. I remember when the HD series came out around 1980 and 4&quot; by 5&quot;'s were only about $2. At the end, they were $8, which is out of sync with the rest of the cost of living price increases. So I hope that this Holographic Consumer Report will help others spend their hard-earned dough wisely! == Notes and References == <references /> 36b2f67fb35aec0e63592146263461e81deb67d2 6 1061 2328 2014-01-01T17:46:47Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 1024 2331 2319 2014-01-01T22:02:29Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 49b9df402e944210ce7c92c10c74f06684797fbd 2343 2331 2014-01-01T23:34:30Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] a047815ca1775a61c3b6b994fba68cfcc48cf469 2351 2343 2014-01-02T00:02:06Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] d3808655ba063d251877278cbb5d5f8f5b75e8fc 2352 2351 2014-01-02T00:03:20Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's #7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 935cb86cc2e898312103a8bad80c92084f9e76fa 2354 2352 2014-01-02T00:10:44Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's \#7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's \#5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's \#6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's \#7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 3479d5748b951c9cd924ebef80e452395a30c642 2355 2354 2014-01-02T00:15:56Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's &#35;7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's &#35;5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's &#35;6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's &#35;7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] cd6c7f19966cd170efd8d541ac8022d8656899e7 2356 2355 2014-01-02T00:19:17Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] e26eb6d2cf89496a6577e43c80cbb75f5c1be08c 2360 2356 2014-01-02T00:27:33Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's #5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's #7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / JD-2 | JD-2]] * [[Ewesly / Holographic Formulae / JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's #6 | Nick's #6]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 536207c03d4ea2f9647bb7d1edbc038d83a38c4a 2363 2360 2014-01-02T00:42:46Z Jsfisher 1 wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] f5b9afc96028070fe0cbebd5a0f42ec9a407d94d 2364 2363 2014-01-02T00:43:30Z Jsfisher 1 /* Hydroquinone */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-4 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1 | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodka D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 62f817ace4a5a1349ad38609473174b0a8e02659 2365 2364 2014-01-02T00:46:04Z Jsfisher 1 wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 2bc33b716175a278df25858b946553ebbefcd8e1 2367 2365 2014-01-02T00:51:56Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ==== Ascorbic acid ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ==== Catechol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ==== Chlorohydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ==== Hydroquinone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ==== Metol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ==== Phenidone ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Pyrogallol ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ==== Colloidal ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ==== General Holographic ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ==== Photographic Film ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ==== Photographic Paper ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ==== Pulsed (Extremely Short Exposures) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ==== Tanning ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] a521231d63351953728ab2ef724977e536dc651a 2368 2367 2014-01-02T16:12:15Z Jsfisher 1 wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == (coming eventually) == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 2ca0f6fd7cd8ebe8e744b44a4c33dbaf19aac448 0 1062 2332 2014-01-01T22:24:17Z Jsfisher 1 Created page with "The first time I saw this formula was in the instruction sheet for the old HRT BB series of plates when they were produced in Germany. So back in the 20th century I dubbed it..." wikitext text/x-wiki The first time I saw this formula was in the instruction sheet for the old HRT BB series of plates when they were produced in Germany. So back in the 20th century I dubbed it BBAA, for Birenheide and Blyth Ascorbic Acid, but I might be the only one calling it this. The original pamphlet did not give it a name. A colleague of mine, Rick Bruck, calls it HRTd, Holographic Recording Technology developer. Steve (LoserSmith) Smith calls the diluted version of it TJ-1, which TJ calls JD-4. (See below.) The current producers of the BB series of plates, Colour Holographic, have replaced the metol with 1 g of phenidone plus a couple other tweaks in their currently recommended developer<ref>I would love to link to their current recipes, but their latest (April 2011) [http://www.colourholographic.com/ web site] does not have a processing page. Click [[Media:ColourHoloBBprocess.pdf | here]] to link to a pdf of the last one that I had downloaded from 2008.</ref> for these plates. == BBAA == from Holographic Recording Materials, circa 1997<ref>[[Media:bb97.pdf | Holographic Recording Technology brochure]]</ref> <p> 4 g&nbsp; Metol<br /> 25 g&nbsp; Ascorbic Acid<br /> 70 g&nbsp; Sodium Carbonate<br /> 15 g Sodium Hydroxide<br /> One litre water<br /> </p> === Development time === <p>5 minutes at 20C (68F) for BB series plates.</p> <p><u>&nbsp;Agitation:</u>&nbsp; Constant</p> == JD-4 Kit == <p>But the exact same ingredients are used in the JD-4 kit sold by Photographers Formulary<ref>[http://stores.photoformulary.com/images/store_version1/04-3040.pdf Photographers’ Formulary JD-4 kit]</ref>, but broken into A and B solutions, so that the JD-4 working strength is half of that of the original BBAA formula. (The original recipe put all the ingredients in just one litre of H20; so an A/B configuration makes twice as much soup for half the price!)&nbsp; This developer, used in the cold water JARB developing scheme, works excellently for the ultra-fine grained Soviet-style materials like PFG-03M or GEO-3<ref>[[Media:chprocess.pdf | Colour Holographics brochure]</ref>.<br /> </p> <p><u>PART A </u><br /> 4 g&nbsp; Metol<br /> 25 g&nbsp; Ascorbic Acid<br /> One litre water</p> <p><u>PART B</u><br /> 70 g&nbsp; Sodium Carbonate<br /> 15 g Sodium Hydroxide<br /> One litre water<br /> </p> <p>Mix equal parts together before use.<br /> </p> <p><u>Development time:&nbsp;</u> <br /> 45 seconds at 22C (72F) for Harman HoloFX plates. <br /> 30 seconds at 18C (65F) for GEO-3 and PFG-03M.&nbsp; <br /> 5 minutes at 20C (68F) for BB series plates. </p> <p><u>Agitation:&nbsp;</u> Constant<br /> </p> == Recommendations == <p>Primary recommendation for developing the GEO-3 and PFG-03M materials. Follow with a rehalogenating/diffusing bleach for no emulsion shrinkage, or 'Chrome bleach for change of replay wavelength in the reflection mode.</p> <p>This developer, even followed by a rehalogenating bleach, applied to BB series plates gives a significant amount of shrinkage, from red to green, which might be a pleasant color for the application.&nbsp; Kodak D-8 or a pyrogallol-based developer helps prevent the color from shifting with these materials.</p> == Shelf Life == <p>Part A can last a month in a tightly stoppered bottle; Part B can last indefinitely.&nbsp; The combined solutions can last at least a day in a covered tray. <br /> </p> == Notes and References == <references /> 762d4f21373d943152476e6015d98694a97addec 2333 2332 2014-01-01T22:25:44Z Jsfisher 1 /* JD-4 Kit */ wikitext text/x-wiki The first time I saw this formula was in the instruction sheet for the old HRT BB series of plates when they were produced in Germany. So back in the 20th century I dubbed it BBAA, for Birenheide and Blyth Ascorbic Acid, but I might be the only one calling it this. The original pamphlet did not give it a name. A colleague of mine, Rick Bruck, calls it HRTd, Holographic Recording Technology developer. Steve (LoserSmith) Smith calls the diluted version of it TJ-1, which TJ calls JD-4. (See below.) The current producers of the BB series of plates, Colour Holographic, have replaced the metol with 1 g of phenidone plus a couple other tweaks in their currently recommended developer<ref>I would love to link to their current recipes, but their latest (April 2011) [http://www.colourholographic.com/ web site] does not have a processing page. Click [[Media:ColourHoloBBprocess.pdf | here]] to link to a pdf of the last one that I had downloaded from 2008.</ref> for these plates. == BBAA == from Holographic Recording Materials, circa 1997<ref>[[Media:bb97.pdf | Holographic Recording Technology brochure]]</ref> <p> 4 g&nbsp; Metol<br /> 25 g&nbsp; Ascorbic Acid<br /> 70 g&nbsp; Sodium Carbonate<br /> 15 g Sodium Hydroxide<br /> One litre water<br /> </p> === Development time === <p>5 minutes at 20C (68F) for BB series plates.</p> <p><u>&nbsp;Agitation:</u>&nbsp; Constant</p> == JD-4 Kit == <p>But the exact same ingredients are used in the JD-4 kit sold by Photographers Formulary<ref>[http://stores.photoformulary.com/images/store_version1/04-3040.pdf Photographers’ Formulary JD-4 kit]</ref>, but broken into A and B solutions, so that the JD-4 working strength is half of that of the original BBAA formula. (The original recipe put all the ingredients in just one litre of H20; so an A/B configuration makes twice as much soup for half the price!)&nbsp; This developer, used in the cold water JARB developing scheme, works excellently for the ultra-fine grained Soviet-style materials like PFG-03M or GEO-3<ref>[[Media:chprocess.pdf | Colour Holographics brochure]</ref>.<br /> </p> <p><u>PART A </u><br /> 4 g&nbsp; Metol<br /> 25 g&nbsp; Ascorbic Acid<br /> One litre water</p> <p><u>PART B</u><br /> 70 g&nbsp; Sodium Carbonate<br /> 15 g Sodium Hydroxide<br /> One litre water<br /> </p> <p>Mix equal parts together before use.<br /> </p> === Development time === 45 seconds at 22C (72F) for Harman HoloFX plates. <br /> 30 seconds at 18C (65F) for GEO-3 and PFG-03M.&nbsp; <br /> 5 minutes at 20C (68F) for BB series plates. <p><u>Agitation:&nbsp;</u> Constant<br /> </p> == Recommendations == <p>Primary recommendation for developing the GEO-3 and PFG-03M materials. Follow with a rehalogenating/diffusing bleach for no emulsion shrinkage, or 'Chrome bleach for change of replay wavelength in the reflection mode.</p> <p>This developer, even followed by a rehalogenating bleach, applied to BB series plates gives a significant amount of shrinkage, from red to green, which might be a pleasant color for the application.&nbsp; Kodak D-8 or a pyrogallol-based developer helps prevent the color from shifting with these materials.</p> == Shelf Life == <p>Part A can last a month in a tightly stoppered bottle; Part B can last indefinitely.&nbsp; The combined solutions can last at least a day in a covered tray. <br /> </p> == Notes and References == <references /> bdeccb42fc9e8811585b602cb7894633646cf6d9 2334 2333 2014-01-01T22:28:32Z Jsfisher 1 wikitext text/x-wiki The first time I saw this formula was in the instruction sheet for the old HRT BB series of plates when they were produced in Germany. So back in the 20th century I dubbed it BBAA, for Birenheide and Blyth Ascorbic Acid, but I might be the only one calling it this. The original pamphlet did not give it a name. A colleague of mine, Rick Bruck, calls it HRTd, Holographic Recording Technology developer. Steve (LoserSmith) Smith calls the diluted version of it TJ-1, which TJ calls JD-4. (See below.) The current producers of the BB series of plates, Colour Holographic, have replaced the metol with 1 g of phenidone plus a couple other tweaks in their currently recommended developer<ref>I would love to link to their current recipes, but their latest (April 2011) [http://www.colourholographic.com/ web site] does not have a processing page. Click [[Media:ColourHoloBBprocess.pdf | here]] to link to a pdf of the last one that I had downloaded from 2008.</ref> for these plates. == BBAA == from Holographic Recording Materials, circa 1997<ref>[[Media:bb97.pdf | Holographic Recording Technology brochure]]</ref> <p> 4 g&nbsp; Metol<br /> 25 g&nbsp; Ascorbic Acid<br /> 70 g&nbsp; Sodium Carbonate<br /> 15 g Sodium Hydroxide<br /> One litre water<br /> </p> === Development time === <p>5 minutes at 20C (68F) for BB series plates.</p> <p><u>Agitation</u>: Constant</p> == JD-4 Kit == <p>But the exact same ingredients are used in the JD-4 kit sold by Photographers Formulary<ref>[http://stores.photoformulary.com/images/store_version1/04-3040.pdf Photographers’ Formulary JD-4 kit]</ref>, but broken into A and B solutions, so that the JD-4 working strength is half of that of the original BBAA formula. (The original recipe put all the ingredients in just one litre of H20; so an A/B configuration makes twice as much soup for half the price!)&nbsp; This developer, used in the cold water JARB developing scheme, works excellently for the ultra-fine grained Soviet-style materials like PFG-03M or GEO-3<ref>[[Media:chprocess.pdf | Colour Holographics brochure]]</ref>.<br /> </p> <p><u>PART A </u><br /> 4 g&nbsp; Metol<br /> 25 g&nbsp; Ascorbic Acid<br /> One litre water</p> <p><u>PART B</u><br /> 70 g&nbsp; Sodium Carbonate<br /> 15 g Sodium Hydroxide<br /> One litre water<br /> </p> <p>Mix equal parts together before use.<br /> </p> === Development time === 45 seconds at 22C (72F) for Harman HoloFX plates. <br /> 30 seconds at 18C (65F) for GEO-3 and PFG-03M.&nbsp; <br /> 5 minutes at 20C (68F) for BB series plates. <p><u>Agitation</u>: Constant<br /> </p> === Recommendations === <p>Primary recommendation for developing the GEO-3 and PFG-03M materials. Follow with a rehalogenating/diffusing bleach for no emulsion shrinkage, or 'Chrome bleach for change of replay wavelength in the reflection mode.</p> <p>This developer, even followed by a rehalogenating bleach, applied to BB series plates gives a significant amount of shrinkage, from red to green, which might be a pleasant color for the application.&nbsp; Kodak D-8 or a pyrogallol-based developer helps prevent the color from shifting with these materials.</p> === Shelf Life === <p>Part A can last a month in a tightly stoppered bottle; Part B can last indefinitely.&nbsp; The combined solutions can last at least a day in a covered tray. <br /> </p> == Notes and References == <references /> e1aef06ffbcb8e100b42e37daa35cabd52ada6c6 2361 2334 2014-01-02T00:29:07Z Jsfisher 1 Jsfisher moved page [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ1]] to [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1]] without leaving a redirect wikitext text/x-wiki The first time I saw this formula was in the instruction sheet for the old HRT BB series of plates when they were produced in Germany. So back in the 20th century I dubbed it BBAA, for Birenheide and Blyth Ascorbic Acid, but I might be the only one calling it this. The original pamphlet did not give it a name. A colleague of mine, Rick Bruck, calls it HRTd, Holographic Recording Technology developer. Steve (LoserSmith) Smith calls the diluted version of it TJ-1, which TJ calls JD-4. (See below.) The current producers of the BB series of plates, Colour Holographic, have replaced the metol with 1 g of phenidone plus a couple other tweaks in their currently recommended developer<ref>I would love to link to their current recipes, but their latest (April 2011) [http://www.colourholographic.com/ web site] does not have a processing page. Click [[Media:ColourHoloBBprocess.pdf | here]] to link to a pdf of the last one that I had downloaded from 2008.</ref> for these plates. == BBAA == from Holographic Recording Materials, circa 1997<ref>[[Media:bb97.pdf | Holographic Recording Technology brochure]]</ref> <p> 4 g&nbsp; Metol<br /> 25 g&nbsp; Ascorbic Acid<br /> 70 g&nbsp; Sodium Carbonate<br /> 15 g Sodium Hydroxide<br /> One litre water<br /> </p> === Development time === <p>5 minutes at 20C (68F) for BB series plates.</p> <p><u>Agitation</u>: Constant</p> == JD-4 Kit == <p>But the exact same ingredients are used in the JD-4 kit sold by Photographers Formulary<ref>[http://stores.photoformulary.com/images/store_version1/04-3040.pdf Photographers’ Formulary JD-4 kit]</ref>, but broken into A and B solutions, so that the JD-4 working strength is half of that of the original BBAA formula. (The original recipe put all the ingredients in just one litre of H20; so an A/B configuration makes twice as much soup for half the price!)&nbsp; This developer, used in the cold water JARB developing scheme, works excellently for the ultra-fine grained Soviet-style materials like PFG-03M or GEO-3<ref>[[Media:chprocess.pdf | Colour Holographics brochure]]</ref>.<br /> </p> <p><u>PART A </u><br /> 4 g&nbsp; Metol<br /> 25 g&nbsp; Ascorbic Acid<br /> One litre water</p> <p><u>PART B</u><br /> 70 g&nbsp; Sodium Carbonate<br /> 15 g Sodium Hydroxide<br /> One litre water<br /> </p> <p>Mix equal parts together before use.<br /> </p> === Development time === 45 seconds at 22C (72F) for Harman HoloFX plates. <br /> 30 seconds at 18C (65F) for GEO-3 and PFG-03M.&nbsp; <br /> 5 minutes at 20C (68F) for BB series plates. <p><u>Agitation</u>: Constant<br /> </p> === Recommendations === <p>Primary recommendation for developing the GEO-3 and PFG-03M materials. Follow with a rehalogenating/diffusing bleach for no emulsion shrinkage, or 'Chrome bleach for change of replay wavelength in the reflection mode.</p> <p>This developer, even followed by a rehalogenating bleach, applied to BB series plates gives a significant amount of shrinkage, from red to green, which might be a pleasant color for the application.&nbsp; Kodak D-8 or a pyrogallol-based developer helps prevent the color from shifting with these materials.</p> === Shelf Life === <p>Part A can last a month in a tightly stoppered bottle; Part B can last indefinitely.&nbsp; The combined solutions can last at least a day in a covered tray. <br /> </p> == Notes and References == <references /> e1aef06ffbcb8e100b42e37daa35cabd52ada6c6 0 1063 2335 2014-01-01T22:34:38Z Jsfisher 1 Created page with "== Developer == <p><u>PART A<strong></strong></u><br /> 20 g&nbsp; Catechol<br /> 10 g&nbsp; Ascorbic Acid&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp..." wikitext text/x-wiki == Developer == <p><u>PART A<strong></strong></u><br /> 20 g&nbsp; Catechol<br /> 10 g&nbsp; Ascorbic Acid&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br /> 10 g&nbsp; Sodium Sulfite&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br /> 50 g&nbsp; Urea<br /> One litre water</p> <p><u>PART B</u><br /> 60 g&nbsp; Sodium Carbonate<br /> One litre water</p> <p>Mix equal parts together before use.</p> === Development time === Reflection holograms: One minute for films, two for plates.<br /> Transmission holograms: Two to four minutes.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<u>&nbsp;Agitation:</u>&nbsp; Constant</p> === Primary recommendation === For developing the discontinued Agfa Holotest 8E56HD and 8E75HD films and plates.&nbsp; Follow with a rehalogenating/diffusing bleach for no emulsion shrinkage, or 'Chrome bleach for change of replay wavelength in the reflection mode.&nbsp; Works well on Slavich PFG-01 plates and Fuji films.&nbsp; Also useful for processing Bulgarian Academy of Sciences HP-490 Holographic plates. === Shelf life === Part A can last a month in a tightly stoppered bottle; Part B can last indefinitely.&nbsp; The combined solutions can last at least a day in a covered tray.</p> == Notes and References == <p>[[Media:CWC2.PDF | D. J. Cooke and A. A. Ward, "Reflection-Hologram Processing for High Efficiency in Silver-Halide Emulsions," Applied Optics 23, 973 (1984)]].</p> <p>Although I wrote [[Media:CWC2g.pdf | this]] a long time ago, I just recently illustrated it with examples of the test strips. The Agfa 8E75HD plates mentioned are long gone, but the developer is still used, and the descriptions of the process and the methodology of testing are still sound. It's a 14 page PDF, so it will take a while to download, but worth it. Some of the stuff mentioned in the footnotes might pop up on this site in the future. 91b59fd95c0eb3e00d6cd94a76d6e24f4fb91ac9 2336 2335 2014-01-01T22:35:10Z Jsfisher 1 /* Development time */ wikitext text/x-wiki == Developer == <p><u>PART A<strong></strong></u><br /> 20 g&nbsp; Catechol<br /> 10 g&nbsp; Ascorbic Acid&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br /> 10 g&nbsp; Sodium Sulfite&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br /> 50 g&nbsp; Urea<br /> One litre water</p> <p><u>PART B</u><br /> 60 g&nbsp; Sodium Carbonate<br /> One litre water</p> <p>Mix equal parts together before use.</p> === Development time === Reflection holograms: One minute for films, two for plates.<br /> Transmission holograms: Two to four minutes. <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<u>&nbsp;Agitation:</u>&nbsp; Constant</p> === Primary recommendation === For developing the discontinued Agfa Holotest 8E56HD and 8E75HD films and plates.&nbsp; Follow with a rehalogenating/diffusing bleach for no emulsion shrinkage, or 'Chrome bleach for change of replay wavelength in the reflection mode.&nbsp; Works well on Slavich PFG-01 plates and Fuji films.&nbsp; Also useful for processing Bulgarian Academy of Sciences HP-490 Holographic plates. === Shelf life === Part A can last a month in a tightly stoppered bottle; Part B can last indefinitely.&nbsp; The combined solutions can last at least a day in a covered tray.</p> == Notes and References == <p>[[Media:CWC2.PDF | D. J. Cooke and A. A. Ward, "Reflection-Hologram Processing for High Efficiency in Silver-Halide Emulsions," Applied Optics 23, 973 (1984)]].</p> <p>Although I wrote [[Media:CWC2g.pdf | this]] a long time ago, I just recently illustrated it with examples of the test strips. The Agfa 8E75HD plates mentioned are long gone, but the developer is still used, and the descriptions of the process and the methodology of testing are still sound. It's a 14 page PDF, so it will take a while to download, but worth it. Some of the stuff mentioned in the footnotes might pop up on this site in the future. e4c95afd80ad6bf2e8e397aee93b21ef52a13339 0 1064 2337 2014-01-01T23:09:16Z Jsfisher 1 Created page with "== Stock Solution == 0.2 g Phenidone<br /> 5 g Hydroquinone <br /> 100 g Sodium Sulfite (Anhydrous) <br /> 5 g Potassium Hydroxide<br /> 12 g Ammonium T..." wikitext text/x-wiki == Stock Solution == 0.2 g Phenidone<br /> 5 g Hydroquinone <br /> 100 g Sodium Sulfite (Anhydrous) <br /> 5 g Potassium Hydroxide<br /> 12 g Ammonium Thiocyanate <br /> One litre water</p> <p><u>Dilution:</u> Add 15 mL of the stock solution to 400 mL of water before use.</p> === Development time === Reflection holograms: twelve to fifteen minutes for plates.</p> <p><u>Temperature:&nbsp;</u> 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;<u>Agitation:&nbsp;</u> None</p> === Primary recommendation === for developing Slavich PFG-03M plates. Doesn&rsquo;t seem to work on the typical holographic stock like Agfa, Ilford, Harman, Fuji, Kodak. (Try it yourself and waste a plate if you don&rsquo;t believe me!) </p> <p>Not only does the development time seem out of step with the rest of the holographic processing world, which usually takes a few minutes, but the <em>lack </em>of agitation definitely sets it apart from the rest. This bath is a colloidal developer, and the silver that is reduced is not of the black filamentary variety, but very small spheres that appear golden-brown-orange, known as colloidal silver. </p> <p>The Ammonium Thiocyanate acts as a fixing agent and dissolves the unexposed silver grains, which swim over to the developing grains in the bright fringes. It is sort of the same idea with a develop-rehalogenate processing scheme, with material moving from dim fringe areas to bright fringe areas, except in a single step developer that leaves behind tiny developed grains. Since there is no removal of material during processing, the replay color is the same as the recording. This processing is usually preceded by a formaldehyde hardening bath, and followed by a non-hardening fixer to avoid shrinkage. </p> <p><u>Shelf life:&nbsp;</u> The Stock Solution can last for months; discard when it turns yellow. The Diluted Solution lasts about a day in a tray.</p> == Notes and References == Contrary to what [http://stores.photoformulary.com/images/store_version1/04-3030gp2.pdf Photographers' Formulary states, this formula was known for many years before any Soviet bloc holographic materials came on the Western market. Whoever invented this recipe is unknown to me at the moment, but since it&rsquo;s such a low number, it might be fun to fantasize that it is one of the recipes used by Denisyuk at the dawn of reflection holography on one of Protas&rsquo;s emulsions!</p> 4dc773f55a132a1f0e1c8b6464217ffaa77c586a 2338 2337 2014-01-01T23:09:44Z Jsfisher 1 wikitext text/x-wiki == Stock Solution == 0.2 g Phenidone<br /> 5 g Hydroquinone <br /> 100 g Sodium Sulfite (Anhydrous) <br /> 5 g Potassium Hydroxide<br /> 12 g Ammonium Thiocyanate <br /> One litre water</p> <p><u>Dilution:</u> Add 15 mL of the stock solution to 400 mL of water before use.</p> === Development time === Reflection holograms: twelve to fifteen minutes for plates.</p> <p><u>Temperature:&nbsp;</u> 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;<u>Agitation:&nbsp;</u> None</p> === Primary recommendation === for developing Slavich PFG-03M plates. Doesn&rsquo;t seem to work on the typical holographic stock like Agfa, Ilford, Harman, Fuji, Kodak. (Try it yourself and waste a plate if you don&rsquo;t believe me!) </p> <p>Not only does the development time seem out of step with the rest of the holographic processing world, which usually takes a few minutes, but the <em>lack </em>of agitation definitely sets it apart from the rest. This bath is a colloidal developer, and the silver that is reduced is not of the black filamentary variety, but very small spheres that appear golden-brown-orange, known as colloidal silver. </p> <p>The Ammonium Thiocyanate acts as a fixing agent and dissolves the unexposed silver grains, which swim over to the developing grains in the bright fringes. It is sort of the same idea with a develop-rehalogenate processing scheme, with material moving from dim fringe areas to bright fringe areas, except in a single step developer that leaves behind tiny developed grains. Since there is no removal of material during processing, the replay color is the same as the recording. This processing is usually preceded by a formaldehyde hardening bath, and followed by a non-hardening fixer to avoid shrinkage. </p> <p><u>Shelf life:&nbsp;</u> The Stock Solution can last for months; discard when it turns yellow. The Diluted Solution lasts about a day in a tray.</p> == Notes and References == Contrary to what [http://stores.photoformulary.com/images/store_version1/04-3030gp2.pdf Photographers' Formulary states, this formula was known for many years before any Soviet bloc holographic materials came on the Western market. Whoever invented this recipe is unknown to me at the moment, but since it&rsquo;s such a low number, it might be fun to fantasize that it is one of the recipes used by Denisyuk at the dawn of reflection holography on one of Protas&rsquo;s emulsions!</p> 2f093b2f415caa85c656148d13e99d74ce4f4d72 2339 2338 2014-01-01T23:10:10Z Jsfisher 1 /* Development time */ wikitext text/x-wiki == Stock Solution == 0.2 g Phenidone<br /> 5 g Hydroquinone <br /> 100 g Sodium Sulfite (Anhydrous) <br /> 5 g Potassium Hydroxide<br /> 12 g Ammonium Thiocyanate <br /> One litre water</p> <p><u>Dilution:</u> Add 15 mL of the stock solution to 400 mL of water before use.</p> === Development time === Reflection holograms: twelve to fifteen minutes for plates. <p><u>Temperature:&nbsp;</u> 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;<u>Agitation:&nbsp;</u> None</p> === Primary recommendation === for developing Slavich PFG-03M plates. Doesn&rsquo;t seem to work on the typical holographic stock like Agfa, Ilford, Harman, Fuji, Kodak. (Try it yourself and waste a plate if you don&rsquo;t believe me!) </p> <p>Not only does the development time seem out of step with the rest of the holographic processing world, which usually takes a few minutes, but the <em>lack </em>of agitation definitely sets it apart from the rest. This bath is a colloidal developer, and the silver that is reduced is not of the black filamentary variety, but very small spheres that appear golden-brown-orange, known as colloidal silver. </p> <p>The Ammonium Thiocyanate acts as a fixing agent and dissolves the unexposed silver grains, which swim over to the developing grains in the bright fringes. It is sort of the same idea with a develop-rehalogenate processing scheme, with material moving from dim fringe areas to bright fringe areas, except in a single step developer that leaves behind tiny developed grains. Since there is no removal of material during processing, the replay color is the same as the recording. This processing is usually preceded by a formaldehyde hardening bath, and followed by a non-hardening fixer to avoid shrinkage. </p> <p><u>Shelf life:&nbsp;</u> The Stock Solution can last for months; discard when it turns yellow. The Diluted Solution lasts about a day in a tray.</p> == Notes and References == Contrary to what [http://stores.photoformulary.com/images/store_version1/04-3030gp2.pdf Photographers' Formulary states, this formula was known for many years before any Soviet bloc holographic materials came on the Western market. Whoever invented this recipe is unknown to me at the moment, but since it&rsquo;s such a low number, it might be fun to fantasize that it is one of the recipes used by Denisyuk at the dawn of reflection holography on one of Protas&rsquo;s emulsions!</p> 14e5b08fbf8e7c6a1ee7fb4f5ba9c95c67072aa7 2340 2339 2014-01-01T23:10:40Z Jsfisher 1 /* Notes and References */ wikitext text/x-wiki == Stock Solution == 0.2 g Phenidone<br /> 5 g Hydroquinone <br /> 100 g Sodium Sulfite (Anhydrous) <br /> 5 g Potassium Hydroxide<br /> 12 g Ammonium Thiocyanate <br /> One litre water</p> <p><u>Dilution:</u> Add 15 mL of the stock solution to 400 mL of water before use.</p> === Development time === Reflection holograms: twelve to fifteen minutes for plates. <p><u>Temperature:&nbsp;</u> 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;<u>Agitation:&nbsp;</u> None</p> === Primary recommendation === for developing Slavich PFG-03M plates. Doesn&rsquo;t seem to work on the typical holographic stock like Agfa, Ilford, Harman, Fuji, Kodak. (Try it yourself and waste a plate if you don&rsquo;t believe me!) </p> <p>Not only does the development time seem out of step with the rest of the holographic processing world, which usually takes a few minutes, but the <em>lack </em>of agitation definitely sets it apart from the rest. This bath is a colloidal developer, and the silver that is reduced is not of the black filamentary variety, but very small spheres that appear golden-brown-orange, known as colloidal silver. </p> <p>The Ammonium Thiocyanate acts as a fixing agent and dissolves the unexposed silver grains, which swim over to the developing grains in the bright fringes. It is sort of the same idea with a develop-rehalogenate processing scheme, with material moving from dim fringe areas to bright fringe areas, except in a single step developer that leaves behind tiny developed grains. Since there is no removal of material during processing, the replay color is the same as the recording. This processing is usually preceded by a formaldehyde hardening bath, and followed by a non-hardening fixer to avoid shrinkage. </p> <p><u>Shelf life:&nbsp;</u> The Stock Solution can last for months; discard when it turns yellow. The Diluted Solution lasts about a day in a tray.</p> == Notes and References == Contrary to what [http://stores.photoformulary.com/images/store_version1/04-3030gp2.pdf Photographers' Formulary] states, this formula was known for many years before any Soviet bloc holographic materials came on the Western market. Whoever invented this recipe is unknown to me at the moment, but since it&rsquo;s such a low number, it might be fun to fantasize that it is one of the recipes used by Denisyuk at the dawn of reflection holography on one of Protas&rsquo;s emulsions!</p> a7669fffbee51598dc7bd4b91c57544e1be03e7b 0 1065 2341 2014-01-01T23:13:40Z Jsfisher 1 Created page with "== Stock Solution == <p>6 g&nbsp; Metol<br /> 7 g&nbsp; Hydroquinone<br /> .8 g&nbsp; Phenidone<br /> 30 g&nbsp; Sodium Sulfite<br /> 60 g&nbsp; Sodium Carbonate<br />..." wikitext text/x-wiki == Stock Solution == <p>6 g&nbsp; Metol<br /> 7 g&nbsp; Hydroquinone<br /> .8 g&nbsp; Phenidone<br /> 30 g&nbsp; Sodium Sulfite<br /> 60 g&nbsp; Sodium Carbonate<br /> 2 g&nbsp; Potassium Bromide<br /> 1 g&nbsp; Na4 EDTA<br /> One litre of water</p> === Developing time === <p>Two minutes.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Constant.</p> <p><u>Shelf life:</u>&nbsp; 6 months in a stoppered bottle, a week in a covered tray.</p> <p>Although it has three developing agents in it, it needs twice as much light as CWC2 or D-19 to produce the same density and holographic results.</p> == Source == [[Media:AgfaBrochure.PDF | Agfa Gevaert Technical Information Bulletin 21.7271(480)]] ef666b094cff8b4ff9c311cd839a594b506fe382 0 1066 2342 2014-01-01T23:33:16Z Jsfisher 1 Created page with "== Stock Solutions == <p><u>PART A</u><br /> 15 g&nbsp; Metol<br /> 7 g&nbsp; Pyrogallol<br /> 20 g&nbsp; Sodium Sulfite<br /> 4 g&nbsp; Potassium Bromide<br /> 2 g&..." wikitext text/x-wiki == Stock Solutions == <p><u>PART A</u><br /> 15 g&nbsp; Metol<br /> 7 g&nbsp; Pyrogallol<br /> 20 g&nbsp; Sodium Sulfite<br /> 4 g&nbsp; Potassium Bromide<br /> 2 g&nbsp; Na4 EDTA<br /> One litre of water</p> <p><u>PART B</u><br /> 60 g&nbsp; Sodium Carbonate<br /> One litre water</p> <p>Mix one part of Part A with 2 parts water and one of Part B.</p> === Development time === <p>Reflection holograms: Two minutes</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<u>&nbsp;Agitation:</u>&nbsp; Constant</p> === Shelf life === Part A might not last too long, but Part B will last indefinitely. === Primary recommendation === by Agfa for reflection holograms when the HD series of Holotest emulsions came out, but somebody gave Agfa a bum steer on this one.&nbsp; I never got good holograms with this formula. == Source == [[Media:AgfaBrochure.PDF | Agfa Gevaert Technical Information Bulletin 21.7271(480)]] 0be5557f544c307482059c825d94dec3c33d5390 0 1067 2344 2014-01-01T23:37:47Z Jsfisher 1 Created page with "== Stock Solutions == <p><u>PART A</u><br /> 10 g&nbsp; Pyrogallol<br /> One litre water</p> <p><u>PART B</u><br /> 60 g&nbsp; Sodium Carbonate<br /> One litre water</..." wikitext text/x-wiki == Stock Solutions == <p><u>PART A</u><br /> 10 g&nbsp; Pyrogallol<br /> One litre water</p> <p><u>PART B</u><br /> 60 g&nbsp; Sodium Carbonate<br /> One litre water</p> <p>Mix equal parts together immediately before use.</p> === Developing times === <p> Reflection holograms: One minute for film, two minutes for plates.&nbsp; <br /> Transmission holograms: Two to four minutes for films or plates.&nbsp; </p> <p><u>Temperature: </u>&nbsp;20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>&nbsp;Agitation:</u>&nbsp; Constant</p> <p>The original recipe for the tanning developer - solvent bleach processing regime, giving low noise transmission holograms or wavelength shifted reflection holograms with a characteristic brown stain on the emulsion.&nbsp; </p> === Primary recommendation === for high speed holographic materials like Kodak SO-253/Type 131 or Agfa's 10E75 or 10E56, and also usable for Agfa 8E materials.&nbsp; Recommended bleach is the silver solvent type like 'Chrome bleach, not diffusion-rehalogenation.&nbsp; Colour Holographics recommends this developer for their BB series of plates. === Shelf life === Tray life of the combined solutions is about 15 minutes, Part A will last two or three days in a full stoppered bottle, but Part B will last indefinitely. == Source == [[Media:PyroChrome.PDF | Walter Spierings, "'Pyrochrome' processing Yields Color-Controlled Results with Silver-Halide Materials", holosphere Volume 10, Numbers 7 and 8, p.1, (1981)]] eb76fa5ea43d842b9661e3bdcea202ec18f8694c 0 1068 2345 2014-01-01T23:40:11Z Jsfisher 1 Created page with "== Stock Solution == <p>90 g Sodium Sulfite<br /> 45 g Hydroquinone<br /> 37.5 g Sodium Hydroxide<br /> 30 g Potassium Bromide<br /> One litre water<br /> Dilute t..." wikitext text/x-wiki == Stock Solution == <p>90 g Sodium Sulfite<br /> 45 g Hydroquinone<br /> 37.5 g Sodium Hydroxide<br /> 30 g Potassium Bromide<br /> One litre water<br /> Dilute two parts developer with one part water. (Yes, that's right, 2:1.)</p> === Development time === One-half to two minutes <p><u>Temperature:</u> 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u> Constant.</p> <p>A high-energy developer that can be used for reflection holograms, albeit a bit noisier than developers especially designed for holography. </p> === Primary recommendation === A good one to start with on BB-640 and BB-520 plates. <p><u>Storage life:</u> Undiluted developer can last for months in tightly stoppered bottle; diluted working solution dies in 24 hours.</p> == Source == Photo Lab Index, Lifetime Edition, Morgan and Morgan, Inc., Dobbs Ferry, New York. f7b4260360d53d3e9592bcc867d1c35a6408e66d 0 1069 2346 2014-01-01T23:42:06Z Jsfisher 1 Created page with "== Stock Solution == <p> 1 g Metol<br /> 75 g Sodium Sulfite<br /> 9 g Hydroquinone<br /> 30 g Sodium Carbonate<br /> 5 g Potassium Bromide<br /> One litre wate..." wikitext text/x-wiki == Stock Solution == <p> 1 g Metol<br /> 75 g Sodium Sulfite<br /> 9 g Hydroquinone<br /> 30 g Sodium Carbonate<br /> 5 g Potassium Bromide<br /> One litre water</p> === Developing time === Two to six minutes. <p><u>Temperature:</u> 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u> Constant.</p> === Shelf life === 6 months in a stoppered bottle, a week in a covered tray. <p>No real experience accumulated on this one, but it probably can be used for holographic purposes, since its strength is somewhere between D-8 and D-19. Useful in the processing of Kodak 16mm Motion Picture Films.</p> == Source == Photo Lab Index, Lifetime Edition, Morgan and Morgan, Inc., Dobbs Ferry, New York. cd7bb6918f3a1472d571f52bd740d01bd9c966da 0 1070 2347 2014-01-01T23:54:49Z Jsfisher 1 Created page with "== Stock Solutions == <p>Kodak's venerable formula D-19 has been modified to suit various applications. The original formula looks like this: === Kodak D-19 === 2 g Metol<b..." wikitext text/x-wiki == Stock Solutions == <p>Kodak's venerable formula D-19 has been modified to suit various applications. The original formula looks like this: === Kodak D-19 === 2 g Metol<br /> 90 g Sodium Sulfite<br /> 8 g Hydroquinone<br /> 52.5 g Sodium Carbonate (monohydrated)<br /> 5 g Potassium Bromide<br /> One litre water === D-19a === The Morgan &amp; Morgan Lifetime Photo Lab Index lists a D-19a, which is a special developer for increasing emulsion speed. To one litre of D-19, add the following just before use:<br /> 20 ml Kodak Anti©Fog No. 2, (0.2% solution)<br /> 1.6 g Hydrazine Dihydrochloride<br /> 30 ml Water<br /> This may be useful for some applications, but the fog level increases rapidly. === D-19b === 2.2 g Metol<br /> 72 g Sodium Sulfite<br /> 8.8 g Hydroquinone<br /> 58 g Sodium Carbonate<br /> 4 g Potassium Bromide<br /> One litre Water What this variation does and why it exists I don't know. Source: 150 Do-It-Yourself Black and White Popular Photographic Formulas, edited by Patrick Dignan, Dignan Photographic Inc., North Hollywood, CA 91606, 1977. === D-19R === This is the replenisher for Kodak D-19, again out of the Photo Lab Index. If great amounts of film are put through a processing machine this replenisher freshens up the used developer in the machine. <br /> 4.5 g Metol <br /> 90 g Sodium Sulfite<br /> 17.5 g Hydroquinone<br /> 52.5 g Sodium Carbonate<br /> 7.5 g Sodium Hydroxide<br /> One litre water<br /> Add to the developer tank 30 ml of D-19R for every 500 square centimeters of film gone through the developer, keeping the volume of developer in the tank constant. === D-19 Plus === <strong>D-19+</strong> is the name I have given to <strong>D-19</strong> doped up with 1.5 grams of phenidone per liter. This concoction was formulated by Hans Bjelkhagen and used to process hundreds of thousands of bubble chamber holograms at Fermilab taken on Agfa 10E75 film with a pulsed Ruby laser. === D-19 Minus === D-19 Minus, or &quot;Amended D-19&quot; as it has also been called, is the basic formula lacking the great amount of sulfite which has been the sore spot of the formulation for the holo-chemists. It boosts sensitivity of the holographic materials about one stop.<br /> 30 g Sodium Sulfite<br /> 2 g Metol (Elon)<br /> 8 g Hydroquinone<br /> 60 g Sodium Carbonate<br /> One litre of water<br /> Cuts down exposure by about a half as compared to regular D-19. Source: Nicholas J. Phillips, &quot;The Making of Successful Holograms&quot;, Proceedings of the First International Symposium on Display Holography, 1982, p.27. === Developing time === One to eight minutes for all materials. Check instructions sheets if available, otherwise start with two minutes <p><u>Temperature:</u>&nbsp; 20C +- 1C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Constant</p> === Shelf life === 6 months in a stoppered bottle, one day in an uncovered tray. d2365f70ef676191600a58f84f218ac839943f37 0 1071 2348 2014-01-01T23:57:47Z Jsfisher 1 Created page with "== Stock Solution == (for photographic papers. A substitute for Kodak's pre-packaged Dektol.) <p> 3 g Metol<br /> 45 g Sodium Sulfite<br /> 12 g Hydroquinone<br /> 8..." wikitext text/x-wiki == Stock Solution == (for photographic papers. A substitute for Kodak's pre-packaged Dektol.) <p> 3 g Metol<br /> 45 g Sodium Sulfite<br /> 12 g Hydroquinone<br /> 80 g Sodium Carbonate (Monohydrated)<br /> 2 g Potassium Bromide<br /> One litre of water</p> <p> <u>Working strength solution:</u> Dilute one part of developer with two parts water. <br /> </p> === Developing time === one and a half minutes for fiber-based papers, one minute for the resin-coated kind. <p><u>Temperature:</u>&nbsp; 20C +- 1C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Constant</p> <p><u>Shelf life:</u>&nbsp;Stock solution in a stoppered bottle 6 months; working solution in a tray, overnight.</p> == Source == Photo Lab Index, Lifetime Edition, Morgan and Morgan, Inc., Dobbs Ferry, New York. <p>One might wonder why a developer for photographic papers would be included in a compendium of developers for holographic films and plates. But if you compare the amounts of Metol and Hydroquinone in this brew and the amounts in the venerable Kodak D-19, you can get the same proportions of the developing agents by diluting two parts of the D-72 stock solution with one part of water. (Sort of the opposite proportion when using this developer for its intended application, photographic paper.) The Sodium Carbonate quantities are similar, there is less Sodium Sulfite present, (possibly a plus!) but there is a lot less restrainer (Potassium Bromide). (Jury's out on that one!)</p> <p>Why this early 20th century photographic formula is important to the 21st century holographers is that this formula works identically to Kodak’s proprietary paper developer, Dektol. I have never encountered the Dektol formula in print, but it must be close to this one in its contents, as prints developed in D-72 need the same exposure and exhibit the same contrast as those developed in Dektol. </p> <p>So if you can find a package of Dektol in a camera store, mix it up and dilute it two parts Dektol to one part water and Voila! D-19 substitute!</p> 799ab8ccbe124a23b1028497283e22cacb93e1fe 0 1072 2349 2014-01-02T00:00:46Z Jsfisher 1 Created page with "== Stock Solution == Kodak D-76 is identical to Ilford ID-11; they are intended for photographic films. <p>2 g Metol<br /> 100 g Sodium Sulfite<br /> 5 g Hydroquinone<b..." wikitext text/x-wiki == Stock Solution == Kodak D-76 is identical to Ilford ID-11; they are intended for photographic films. <p>2 g Metol<br /> 100 g Sodium Sulfite<br /> 5 g Hydroquinone<br /> 2 g Borax<br /> One litre of water</p> <p>Although the above stock solution can be used and re-used, the developer yields finer grain when used in a &quot;single-shot&quot; one to one dilution. Follow recommended time and temperature and agitation on the photographic film's instruction sheet.</p> === Shelf life === 6 months in a stoppered bottle. == Source == Photo Lab Index, Lifetime Edition, Morgan and Morgan, Inc., Dobbs Ferry, New York. <p>This developer is included in the list as a comparison to the components of a holographic developer. Notice that the Metol and Hydroquinone strengths are about equal to D-19, but its pH is much lower due to using Borax instead of Sodium Carbonate. And there’s a heck of a lot more Sodium Sulfite, but that’s OK, as photographic films have a heck of a lot more silver in them!</p> <p>This developer would be a good place to start if one were to try shooting photographs on holographic film. the results might be a bit on the contrasty side, and a better choice for this experiment might be the use of the POTA formula.</p> <p>Another holographic use for D-76 is to add 2.5 g Ammonium Thiocyanate per liter of stock solution, dilute this brew 1:15 and use it as a colloidal developer like GP-2 with the ungodly development time of 30 minutes at 20 C with no agitation. (Bjelkhagen, p.150)</p> eb122a34b3b90c13338f5c1c8057472f2cf6caaa 2350 2349 2014-01-02T00:01:43Z Jsfisher 1 Jsfisher moved page [[Ewesly / Holographic Formulae / Kodka D-76]] to [[Ewesly / Holographic Formulae / Kodak D-76]] without leaving a redirect wikitext text/x-wiki == Stock Solution == Kodak D-76 is identical to Ilford ID-11; they are intended for photographic films. <p>2 g Metol<br /> 100 g Sodium Sulfite<br /> 5 g Hydroquinone<br /> 2 g Borax<br /> One litre of water</p> <p>Although the above stock solution can be used and re-used, the developer yields finer grain when used in a &quot;single-shot&quot; one to one dilution. Follow recommended time and temperature and agitation on the photographic film's instruction sheet.</p> === Shelf life === 6 months in a stoppered bottle. == Source == Photo Lab Index, Lifetime Edition, Morgan and Morgan, Inc., Dobbs Ferry, New York. <p>This developer is included in the list as a comparison to the components of a holographic developer. Notice that the Metol and Hydroquinone strengths are about equal to D-19, but its pH is much lower due to using Borax instead of Sodium Carbonate. And there’s a heck of a lot more Sodium Sulfite, but that’s OK, as photographic films have a heck of a lot more silver in them!</p> <p>This developer would be a good place to start if one were to try shooting photographs on holographic film. the results might be a bit on the contrasty side, and a better choice for this experiment might be the use of the POTA formula.</p> <p>Another holographic use for D-76 is to add 2.5 g Ammonium Thiocyanate per liter of stock solution, dilute this brew 1:15 and use it as a colloidal developer like GP-2 with the ungodly development time of 30 minutes at 20 C with no agitation. (Bjelkhagen, p.150)</p> eb122a34b3b90c13338f5c1c8057472f2cf6caaa 0 1073 2353 2014-01-02T00:06:03Z Jsfisher 1 Created page with "== Stock Solution == ''Lucky Number 7'' <p>30 g&nbsp; Sodium Sulfite<br /> 10 g&nbsp; Ascorbic Acid<br /> &nbsp;2 g&nbsp; Chlorohydroquinone<br /> &nbsp;5 g&nbsp; Potas..." wikitext text/x-wiki == Stock Solution == ''Lucky Number 7'' <p>30 g&nbsp; Sodium Sulfite<br /> 10 g&nbsp; Ascorbic Acid<br /> &nbsp;2 g&nbsp; Chlorohydroquinone<br /> &nbsp;5 g&nbsp; Potassium Bromide<br /> 10 g&nbsp; Sodium Metaborate (Kodalk)<br /> 60 g&nbsp; Sodium Carbonate (Anhydrous)<br /> One litre water</p> === Developing time === Three to four minutes for all materials. <p><u>Temperature:</u>&nbsp; 22C +- 1C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Constant</p> === Shelf life === Probably about a month. <p>The first developer encountered which gave a better signal to noise ratio than CWC2, but with the same brightness.&nbsp; It doesn't seem to work with Agfa film, but gives the best possible results on plates.&nbsp; It was the main developer for true-color holography at Lake Forest College circa 1990.&nbsp; A properly exposed plate will sit in this soup for thirty seconds before any density starts to appear.&nbsp; It will last all day in a tray, about one week in a full stoppered bottle. </p> == Source == [[Media:NickWorkhorse.PDF | Nicholas J. Phillips, "The Silver Halides - the Workhorse of the Holography Business", Proceedings of the International Symposium on Display Holography, Volume III, 1988, p.35]]. <p>I dubbed this soup LN-7 as it was the seventh formula he had published in that paper, and it seemed to lower the noise compared to other developers thanks to the addition of the potassium bromide restrainer, hence Low Noise or Lucky Number 7.</p> 5caa5fa2eb01aeaf7b0611c1d0ca126e8d2941c9 2357 2353 2014-01-02T00:20:11Z Jsfisher 1 Jsfisher moved page [[Ewesly / Holographic Formulae / LN-7, Nick's]] to [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7]] without leaving a redirect wikitext text/x-wiki == Stock Solution == ''Lucky Number 7'' <p>30 g&nbsp; Sodium Sulfite<br /> 10 g&nbsp; Ascorbic Acid<br /> &nbsp;2 g&nbsp; Chlorohydroquinone<br /> &nbsp;5 g&nbsp; Potassium Bromide<br /> 10 g&nbsp; Sodium Metaborate (Kodalk)<br /> 60 g&nbsp; Sodium Carbonate (Anhydrous)<br /> One litre water</p> === Developing time === Three to four minutes for all materials. <p><u>Temperature:</u>&nbsp; 22C +- 1C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Constant</p> === Shelf life === Probably about a month. <p>The first developer encountered which gave a better signal to noise ratio than CWC2, but with the same brightness.&nbsp; It doesn't seem to work with Agfa film, but gives the best possible results on plates.&nbsp; It was the main developer for true-color holography at Lake Forest College circa 1990.&nbsp; A properly exposed plate will sit in this soup for thirty seconds before any density starts to appear.&nbsp; It will last all day in a tray, about one week in a full stoppered bottle. </p> == Source == [[Media:NickWorkhorse.PDF | Nicholas J. Phillips, "The Silver Halides - the Workhorse of the Holography Business", Proceedings of the International Symposium on Display Holography, Volume III, 1988, p.35]]. <p>I dubbed this soup LN-7 as it was the seventh formula he had published in that paper, and it seemed to lower the noise compared to other developers thanks to the addition of the potassium bromide restrainer, hence Low Noise or Lucky Number 7.</p> 5caa5fa2eb01aeaf7b0611c1d0ca126e8d2941c9 0 1074 2358 2014-01-02T00:22:37Z Jsfisher 1 Created page with "== Stock Solutions == <p><u>PART A</u><br /> 60 g&nbsp; Sodium Sulfite<br /> 20 g&nbsp; Catechol<br /> 10 g&nbsp; Hydroquinone<br /> 10 g&nbsp; Potassium Bromide<br />..." wikitext text/x-wiki == Stock Solutions == <p><u>PART A</u><br /> 60 g&nbsp; Sodium Sulfite<br /> 20 g&nbsp; Catechol<br /> 10 g&nbsp; Hydroquinone<br /> 10 g&nbsp; Potassium Bromide<br /> One litre water</p> <p><u>PART B</u><br /> 20 g&nbsp; Sodium Metaborate<br /> 120 g&nbsp; Sodium Carbonate<br /> One liter water</p> <p>Mix equal parts together before use.</p> === Development time === Four to five minutes <p><u>Temperature:</u>&nbsp; 23C +- 1C&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Constant</p> === Primary recommendation === for transmission holograms on Ilford green-sensitive materials, followed by a rehalogenating-diffusing bleach. Properly exposed plates will wait thirty seconds before showing signs of development. === Shelf life === Part A can last a month in a tightly stoppered bottle; Part B can last indefinitely.&nbsp; The combined solutions can last a day in a covered tray. == Source == [[Media:NickWorkhorse.PDF | Nicholas J. Phillips, &quot;The Silver Halides - the Workhorse of the Holography Business&quot;, Proceedings of the International Symposium on Display Holography, Volume III, 1988, p.35]]. 904d0dd1fe950cea5cfda33f479271ce5340b933 0 1075 2359 2014-01-02T00:25:32Z Jsfisher 1 Created page with "== Nick's Number 6 == === Stock Solutions === <p><u>PART A</u><br /> 10 g&nbsp; Pyrogallol<br /> 10 g&nbsp; Potassium Bromide<br /> One litre water</p> <p><u>PART B</u><..." wikitext text/x-wiki == Nick's Number 6 == === Stock Solutions === <p><u>PART A</u><br /> 10 g&nbsp; Pyrogallol<br /> 10 g&nbsp; Potassium Bromide<br /> One litre water</p> <p><u>PART B</u><br /> 20 g&nbsp; Sodium Metaborate<br /> 120 g&nbsp; Sodium Carbonate<br /> One liter water</p> === Development time === Five minutes <p><u>Temperature:</u>&nbsp; 23C +- 1C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Constant</p> === Shelf life=== Part A probably a few days to a week, Part B indefinitely.</p> <p>Primary recommendation for Ilford green-sensitive materials for same wavelength replay in the reflection mode when followed by a rehalogenating bleach.&nbsp; SP737T will work in this brew but at a stop loss in speed.&nbsp; A properly exposed plate will sit in this brew for a half a minute before any darkening appears.</p> <p>Tray life of the combined solutions is about 15 minutes, Part A will last two or three days in a full stoppered bottle, but Part B will last indefinitely.</p> == Source == [[Media:NickWorkhorse.PDF | Nicholas J. Phillips, "The Silver Halides - the Workhorse of the Holography Business", Proceedings of the International Symposium on Display Holography, Volume III, 1988, p.35]]. eeda330481b3ccc47b45db6bf1c0920f2f638744 0 1076 2362 2014-01-02T00:33:59Z Jsfisher 1 Created page with "== SM-6 Developer == === Stock Solutions === <p> 18 g Ascorbic Acid<br /> 12 g Sodium Hydroxide<br /> 28.4 g Sodium Phosphate (dibasic)<br /> 6 g Phenidone<br /> One..." wikitext text/x-wiki == SM-6 Developer == === Stock Solutions === <p> 18 g Ascorbic Acid<br /> 12 g Sodium Hydroxide<br /> 28.4 g Sodium Phosphate (dibasic)<br /> 6 g Phenidone<br /> One litre water</p> <p>Sometimes the formula is divided into two parts, so that the stock solutions can last longer:</p> <p><u>PART A<strong></strong></u><br /> 36 g&nbsp; Ascorbic Acid&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br /> 12 g&nbsp; Phenidone&nbsp; <br /> One litre water</p> <p><u>PART B</u><br /> 24 g Sodium Hydroxide<br /> 56.8 g Sodium Phosphate (dibasic)<br /> One litre water</p> <p>Hot H2O alert! Phenidone is almost impossible to dissolve unless the water is tap water hot, like &gt; 100F or 38C or so.</p> === Development time === Reflection holograms: One minute for films, two for plates.<br /> Transmission holograms: Two to four minutes. <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<u>&nbsp;Agitation:</u>&nbsp; Constant</p> === Primary recommendation === for developing the discontinued Agfa Holotest 8E56HD and 8E75HD films and plates as well as any other manufacturer&rsquo;s product that is exposed to extremely short laser pulses, such as Q-Switched (or even free-lasing) Ruby or YAG lasers.&nbsp; Follow with a rehalogenating/diffusing bleach for no emulsion shrinkage, or 'Chrome bleach for change of replay wavelength in the reflection mode.&nbsp; It is also the [http://www.geola.lt/pepperit/lt/holography_materials/colour/ primary recommendation by Geola UAB] for the Slavich PFG-03C or Sphere-S GEO-3 panchromatic holographic emulsions in continuous wave mode with either a Formaldehyde Pre-Hardening Bath or even with Formaldehyde added to the developer. (10 ml 37% Formaldehyde solution to 1 liter of developer) === Shelf life === Part A can last a month in a tightly stoppered bottle; Part B can last indefinitely.&nbsp; The combined solutions can last at least a day in a covered tray. == Source == [[Media:SM6rant.pdf | Click here]] for a detailed synopsis of the discovery of SM-6; [[Media:sm6.pdf | click here]] for an interesting in-house report filed by Salim Idriss, a summer intern at Northwestern University, as part of his scholarship, on the same topic, followed by experimental verification. b2399789362ee3d8198bb1f95dbd13999c441942 0 1077 2366 2014-01-02T00:50:50Z Jsfisher 1 Created page with "<p>The replay color of a reflection hologram depends not only on the color of the laser recording the hologram, but also on the way the hologram is processed. For bleached ho..." wikitext text/x-wiki <p>The replay color of a reflection hologram depends not only on the color of the laser recording the hologram, but also on the way the hologram is processed. For bleached holograms on silver halide plates, the processing will either recreate the laser color, (develop-rehalogenating bleach for no emulsion shrinkage), or the hologram will reconstruct at colors shorter than the laser's wavelength due to shrinkage of the coating through loss of material either through removal of silver halides in fixing or by loss of developed silver in a silver solvent bleach. Overall control of image color is afforded by the latter two methods, as the shrinkage of the coating is proportional to the amount of developed silver and the color can be controlled by juggling of exposure and development times. However the range of hues is limited, with only oranges and greens possible with a helium neon laser using these schemes. If the hologram is exposed to first one and then another of two different objects, both objects will be the same color, unless some clever masking scheme is used.</p> <p>But the artist needs to make holograms with different colored images in it but usually they can only afford one color of laser (if that). In the original triethanolamine duo color paper in holosphere<ref>Jeff Blyth, Pseudoscopic Moldmaking Handy Trick for Denisyuk Holographers, holosphere Vol 8, #3.</ref>, Jeff Blythe explained how he recorded two different colored images in the same hologram using only a helium neon laser. The trick was to record the two separate interference systems in the emulsion while varying the thickness of the coating between the two exposures. </p> <p>WHY IT WORKS: An ideal reflection hologram recording would have layers of varying refractive index to represent the bright and dark fringes present during. Their thickness would be 1/4 of the recording laser's wavelength, so that the exact same wavelength of recording out of all of those present in the white light fits in them snugly and is strongly reflected thanks to Bragg diffraction. If the material in the holographic recording layer were to shrink, a shorter wavelength than the original one would fit into the fringe structure and the color of reconstruction would be greener or even bluer. </p> <p>Blyth's ingenuity lies in pre-swelling the emulsion before exposure to make it thicker. After exposure and processing, which removes the plumping agent, the emulsion shrinks back to its original out of the box thickness. The fringe system also shrinks, inversely proportional to the swelled state during exposure. A higher concentration of plumping agent in the pre-soak will expand the gelatin coating more, so the eventual collapse of the fringe spacing will be more dramatic and bluer.</p> <p><strong>TEA</strong> (<strong>T</strong>ri<strong>E</strong>thanol<strong>A</strong>mine) is a water soluble oil, but it does not evaporate like water. A holographic plate soaked in a 10% solution of TEA in water will swell up three to ten times its original thickness while wet, but when the water dries out of the gelatinous sponge, the ten per cent of oily TEA is left behind, now swelling the emulsion to about 10% thicker than at first. The plate is now exposed to 633 nm He-Ne light for a single beam reflection hologram. The TEA is washed out. The hologram is processed and dried so that it is the out of the box thickness, which is 10% less than when it had been exposed. The holographic pattern is now 10% thinner too, and it reflects a color about 10% shorter in wavelength, about 570 nm, a yellowish green.</p> <p>MAKING A TRIETHANLOAMINE PALETTE: Lay out bottles of different concentrations of TEA; usually a series of 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0 per cent solutions will span the visible and maybe even into the ultraviolet in some cases with a sensible division of the spectrum. Soak a plate or two in each concentration for two to five minutes, the soaking time is not as critical as the time spent exposed to your &quot;safe&quot;light.</p> <p>The truly critical step in triethanolamining is the elimination of streaking. The viscous TEA flows at a different rate than water if the plate is held vertically, and dries in messy streaks over the plate. The original practitioners, Lon Moore and John Kaufmann, used windshield wiper blades to squeegee most of the syrup out of the emulsion, eliminating streaks and quickening drying times. However this technique requires a knack which needs to be mastered, applying even pressure from edge to edge during the wipe and being able to do it consistently from plate to plate otherwise your calibration palette is worthless.</p> <p>I have heard that Edwina Orr of Richmond Holographic Studios uses an air knife which blows a concentrated stream of air across the plate as it is conveyed below it on a sliding drawer type arrangement to standardize production.</p> <p>Greg Cherry and Nancy Gorglione have described<ref>Greg Cherry, Spin Coater for Triethanolamine Pretreatment, L.A.S.E.R. News, vol 5, #2, 1989</ref> their spin coating apparatus, and thanks to a donation to the Holography Dep't @ SAIC by Weston Morris of his Swirl Art machine we have our own. This is the most fun way of TEAing, plus it is consistent, no streaks, and the plate is dry enough to shoot most assuredly after 5 minutes on the machine, but usually two minutes suffices for the lower concentrations in most cases.</p> <p>After a plate is soaked and dried for each concentration, they should be exposed for one half the normal exposure they would get for processing in CWC2 and copper sulfate bleach (or your favorite rehalogenator). The pre-soak in water dissolves out the excess bromine put in during manufacture to extend the shelf life of the plates, so there is an increase in sensitivity of about one stop. Before processing, rinse the plates in water to remove the TEA so that it won't pollute the developer. The CWC2 developer followed by a rehalogenating bleach type of processing is chosen for its non-shrinking virtue. After gentle air drying, the different concentrations can be sorted by their replay colors.</p> <p><strong>QUESTION?</strong> What has happened to the reference angle?</p> <p><strong>FOR DUO COLOR HOLOGRAMS:</strong> Usually the practice is to pre-soak for the highest concentration you want to use. Wash the plate after the first color's exposure, soak in the second color's TEA bath, or plain Kodak Photo-Flo if the second color is to be laser red. You could start with both exposures being equal between the two at first, but may have to tweak one or the other up or down for color blending.</p> <p><strong>POSTSCRIPT 10/13/11:</strong> I wrote this in the '80's, but the technique should work well with the current crop of emulsions like Slavich PFG-01, BB-640, and Harman. One of these days I will post a picture of my Palette.</p> == Notes and References == <references /> b04da8d8f7e594cbf2478db1a5989d1a62130b36 6 1078 2369 2014-01-03T00:07:42Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1079 2370 2014-01-03T00:07:47Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1080 2371 2014-01-03T00:07:51Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1081 2372 2014-01-03T00:07:55Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1082 2373 2014-01-03T00:08:00Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1083 2374 2014-01-03T00:08:06Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1084 2375 2014-01-03T00:08:09Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 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519c08da88276b2f47bc6fb30637d415fd0d804e 0 1189 2480 2014-01-03T00:16:12Z Jsfisher 1 Created page with "<gallery> Image:_1100501231.jpg Image:_1040141440.jpg Image:_1030810021.jpg Image:_1014702244.jpg Image:_1010720061.jpg Image:_0922383004.jpg Image:_0658096756.jpg Image:_040..." wikitext text/x-wiki <gallery> Image:_1100501231.jpg Image:_1040141440.jpg Image:_1030810021.jpg Image:_1014702244.jpg Image:_1010720061.jpg Image:_0922383004.jpg Image:_0658096756.jpg Image:_0401323841.jpg Image:_0301181007.jpg Image:_0216321002.jpg Image:_0135203801.jpg Image:_0180238110.jpg Image:_9967859588.jpg Image:_9877788915.jpg Image:_9776667877.jpg Image:_9669569686.jpg Image:_9665681676.jpg Image:_9433122769.jpg Image:_9365366897.jpg Image:_9098585975.jpg Image:_8969888188.jpg Image:_8966890566.jpg Image:_8966211830.jpg Image:_8806766872.jpg Image:_8797675468.jpg Image:_8689779786.jpg Image:_8566658590.jpg Image:_8559669699.jpg Image:_8556695858.jpg Image:_8375928868.jpg Image:_7936786973.jpg Image:_7898550768.jpg Image:_7897897854.jpg Image:_7886857585.jpg Image:_7865888585.jpg Image:_7795686754.jpg Image:_7686879788.jpg Image:_7628772022.jpg Image:_7344900931.jpg Image:_7301802383.jpg Image:_7285805610.jpg Image:_7048122688.jpg Image:_6998798979.jpg Image:_6964977898.jpg Image:_6917980658.jpg Image:_6886778768.jpg Image:_6857395588.jpg Image:_6676556775.jpg Image:_6577997818.jpg Image:_6168628659.jpg Image:_6031012412.jpg Image:_5982766779.jpg Image:_5896896878.jpg Image:_5887279976.jpg Image:_5813402111.jpg Image:_5769619788.jpg Image:_5679697557.jpg Image:_5598937595.jpg Image:_5555997505.jpg Image:_5397965695.jpg Image:_5230840130.jpg Image:_5202534312.jpg Image:_4989258979.jpg Image:_4798375367.jpg Image:_4491018310.jpg Image:_4446342804.jpg Image:_4445241011.jpg Image:_4381147213.jpg Image:_4334413223.jpg Image:_4333150115.jpg Image:_4230361302.jpg Image:_4222203169.jpg Image:_4208144834.jpg Image:_4142123020.jpg Image:_4107001732.jpg Image:_4105421441.jpg Image:_4101104143.jpg Image:_4020354321.jpg Image:_3503184291.jpg Image:_3423803472.jpg Image:_3340040030.jpg Image:_3322208443.jpg Image:_3262211318.jpg Image:_3240344441.jpg Image:_3213207244.jpg Image:_3201343141.jpg Image:_3106320831.jpg Image:_3060318303.jpg Image:_3024322240.jpg Image:_2933120332.jpg Image:_2504132239.jpg Image:_2461325223.jpg Image:_2413204214.jpg Image:_2392310111.jpg Image:_2304094416.jpg Image:_2183228336.jpg Image:_2144023701.jpg Image:_2133577056.jpg Image:_2040434233.jpg Image:_2032741081.jpg Image:_1930461421.jpg Image:_1520212141.jpg Image:_1441070312.jpg Image:_1432481432.jpg Image:_1431146004.jpg Image:_1412035567.jpg Image:_1332755825.jpg Image:_1323415004.jpg Image:_1223223012.jpg Image:_1221460314.jpg Image:_1210024472.jpg </gallery> 150654031f1cbcec9632fd5abf5b00a8bd6c82bc 2483 2480 2014-01-03T03:25:46Z Jsfisher 1 wikitext text/x-wiki This content was derived from [http://nlutie.com/ewesly/Plateboxes Ed Wesly's website]. There, the images are presented as a slide show, organized by brand. Click on any image below for a full-size version of the picture. <gallery> Image:_1100501231.jpg Image:_1040141440.jpg Image:_1030810021.jpg Image:_1014702244.jpg Image:_1010720061.jpg Image:_0922383004.jpg Image:_0658096756.jpg Image:_0401323841.jpg Image:_0301181007.jpg Image:_0216321002.jpg Image:_0135203801.jpg Image:_0180238110.jpg Image:_9967859588.jpg Image:_9877788915.jpg Image:_9776667877.jpg Image:_9669569686.jpg Image:_9665681676.jpg Image:_9433122769.jpg Image:_9365366897.jpg Image:_9098585975.jpg Image:_8969888188.jpg Image:_8966890566.jpg Image:_8966211830.jpg Image:_8806766872.jpg Image:_8797675468.jpg Image:_8689779786.jpg Image:_8566658590.jpg Image:_8559669699.jpg Image:_8556695858.jpg Image:_8375928868.jpg Image:_7936786973.jpg Image:_7898550768.jpg Image:_7897897854.jpg Image:_7886857585.jpg Image:_7865888585.jpg Image:_7795686754.jpg Image:_7686879788.jpg Image:_7628772022.jpg Image:_7344900931.jpg Image:_7301802383.jpg Image:_7285805610.jpg Image:_7048122688.jpg Image:_6998798979.jpg Image:_6964977898.jpg Image:_6917980658.jpg Image:_6886778768.jpg Image:_6857395588.jpg Image:_6676556775.jpg Image:_6577997818.jpg Image:_6168628659.jpg Image:_6031012412.jpg Image:_5982766779.jpg Image:_5896896878.jpg Image:_5887279976.jpg Image:_5813402111.jpg Image:_5769619788.jpg Image:_5679697557.jpg Image:_5598937595.jpg Image:_5555997505.jpg Image:_5397965695.jpg Image:_5230840130.jpg Image:_5202534312.jpg Image:_4989258979.jpg Image:_4798375367.jpg Image:_4491018310.jpg Image:_4446342804.jpg Image:_4445241011.jpg Image:_4381147213.jpg Image:_4334413223.jpg Image:_4333150115.jpg Image:_4230361302.jpg Image:_4222203169.jpg Image:_4208144834.jpg Image:_4142123020.jpg Image:_4107001732.jpg Image:_4105421441.jpg Image:_4101104143.jpg Image:_4020354321.jpg Image:_3503184291.jpg Image:_3423803472.jpg Image:_3340040030.jpg Image:_3322208443.jpg Image:_3262211318.jpg Image:_3240344441.jpg Image:_3213207244.jpg Image:_3201343141.jpg Image:_3106320831.jpg Image:_3060318303.jpg Image:_3024322240.jpg Image:_2933120332.jpg Image:_2504132239.jpg Image:_2461325223.jpg Image:_2413204214.jpg Image:_2392310111.jpg Image:_2304094416.jpg Image:_2183228336.jpg Image:_2144023701.jpg Image:_2133577056.jpg Image:_2040434233.jpg Image:_2032741081.jpg Image:_1930461421.jpg Image:_1520212141.jpg Image:_1441070312.jpg Image:_1432481432.jpg Image:_1431146004.jpg Image:_1412035567.jpg Image:_1332755825.jpg Image:_1323415004.jpg Image:_1223223012.jpg Image:_1221460314.jpg Image:_1210024472.jpg </gallery> a2f28cc126b6680a871a23a61692dc5ff65c440c 2484 2483 2014-01-03T03:26:50Z Jsfisher 1 wikitext text/x-wiki This content was derived from [http://nlutie.com/ewesly/PlateBoxes Ed Wesly's website]. There, the images are presented as a slide show, organized by brand. Click on any image below for a full-size version of the picture. <gallery> Image:_1100501231.jpg Image:_1040141440.jpg Image:_1030810021.jpg Image:_1014702244.jpg Image:_1010720061.jpg Image:_0922383004.jpg Image:_0658096756.jpg Image:_0401323841.jpg Image:_0301181007.jpg Image:_0216321002.jpg Image:_0135203801.jpg Image:_0180238110.jpg Image:_9967859588.jpg Image:_9877788915.jpg Image:_9776667877.jpg Image:_9669569686.jpg Image:_9665681676.jpg Image:_9433122769.jpg Image:_9365366897.jpg Image:_9098585975.jpg Image:_8969888188.jpg Image:_8966890566.jpg Image:_8966211830.jpg Image:_8806766872.jpg Image:_8797675468.jpg Image:_8689779786.jpg Image:_8566658590.jpg Image:_8559669699.jpg Image:_8556695858.jpg Image:_8375928868.jpg Image:_7936786973.jpg Image:_7898550768.jpg Image:_7897897854.jpg Image:_7886857585.jpg Image:_7865888585.jpg Image:_7795686754.jpg Image:_7686879788.jpg Image:_7628772022.jpg Image:_7344900931.jpg Image:_7301802383.jpg Image:_7285805610.jpg Image:_7048122688.jpg Image:_6998798979.jpg Image:_6964977898.jpg Image:_6917980658.jpg Image:_6886778768.jpg Image:_6857395588.jpg Image:_6676556775.jpg Image:_6577997818.jpg Image:_6168628659.jpg Image:_6031012412.jpg Image:_5982766779.jpg Image:_5896896878.jpg Image:_5887279976.jpg Image:_5813402111.jpg Image:_5769619788.jpg Image:_5679697557.jpg Image:_5598937595.jpg Image:_5555997505.jpg Image:_5397965695.jpg Image:_5230840130.jpg Image:_5202534312.jpg Image:_4989258979.jpg Image:_4798375367.jpg Image:_4491018310.jpg Image:_4446342804.jpg Image:_4445241011.jpg Image:_4381147213.jpg Image:_4334413223.jpg Image:_4333150115.jpg Image:_4230361302.jpg Image:_4222203169.jpg Image:_4208144834.jpg Image:_4142123020.jpg Image:_4107001732.jpg Image:_4105421441.jpg Image:_4101104143.jpg Image:_4020354321.jpg Image:_3503184291.jpg Image:_3423803472.jpg Image:_3340040030.jpg Image:_3322208443.jpg Image:_3262211318.jpg Image:_3240344441.jpg Image:_3213207244.jpg Image:_3201343141.jpg Image:_3106320831.jpg Image:_3060318303.jpg Image:_3024322240.jpg Image:_2933120332.jpg Image:_2504132239.jpg Image:_2461325223.jpg Image:_2413204214.jpg Image:_2392310111.jpg Image:_2304094416.jpg Image:_2183228336.jpg Image:_2144023701.jpg Image:_2133577056.jpg Image:_2040434233.jpg Image:_2032741081.jpg Image:_1930461421.jpg Image:_1520212141.jpg Image:_1441070312.jpg Image:_1432481432.jpg Image:_1431146004.jpg Image:_1412035567.jpg Image:_1332755825.jpg Image:_1323415004.jpg Image:_1223223012.jpg Image:_1221460314.jpg Image:_1210024472.jpg </gallery> 6a033fecf6f435df2e7de58b50923e8a248ea13e 2485 2484 2014-01-03T03:27:36Z Jsfisher 1 wikitext text/x-wiki This content was derived from '''[http://nlutie.com/ewesly/PlateBoxes Ed Wesly's website]'''. There, the images are presented as a slide show, organized by brand. Click on any image below for a full-size version of the picture. <gallery> Image:_1100501231.jpg Image:_1040141440.jpg Image:_1030810021.jpg Image:_1014702244.jpg Image:_1010720061.jpg Image:_0922383004.jpg Image:_0658096756.jpg Image:_0401323841.jpg Image:_0301181007.jpg Image:_0216321002.jpg Image:_0135203801.jpg Image:_0180238110.jpg Image:_9967859588.jpg Image:_9877788915.jpg Image:_9776667877.jpg Image:_9669569686.jpg Image:_9665681676.jpg Image:_9433122769.jpg Image:_9365366897.jpg Image:_9098585975.jpg Image:_8969888188.jpg Image:_8966890566.jpg Image:_8966211830.jpg Image:_8806766872.jpg Image:_8797675468.jpg Image:_8689779786.jpg Image:_8566658590.jpg Image:_8559669699.jpg Image:_8556695858.jpg Image:_8375928868.jpg Image:_7936786973.jpg Image:_7898550768.jpg Image:_7897897854.jpg Image:_7886857585.jpg Image:_7865888585.jpg Image:_7795686754.jpg Image:_7686879788.jpg Image:_7628772022.jpg Image:_7344900931.jpg Image:_7301802383.jpg Image:_7285805610.jpg Image:_7048122688.jpg Image:_6998798979.jpg Image:_6964977898.jpg Image:_6917980658.jpg Image:_6886778768.jpg Image:_6857395588.jpg Image:_6676556775.jpg Image:_6577997818.jpg Image:_6168628659.jpg Image:_6031012412.jpg Image:_5982766779.jpg Image:_5896896878.jpg Image:_5887279976.jpg Image:_5813402111.jpg Image:_5769619788.jpg Image:_5679697557.jpg Image:_5598937595.jpg Image:_5555997505.jpg Image:_5397965695.jpg Image:_5230840130.jpg Image:_5202534312.jpg Image:_4989258979.jpg Image:_4798375367.jpg Image:_4491018310.jpg Image:_4446342804.jpg Image:_4445241011.jpg Image:_4381147213.jpg Image:_4334413223.jpg Image:_4333150115.jpg Image:_4230361302.jpg Image:_4222203169.jpg Image:_4208144834.jpg Image:_4142123020.jpg Image:_4107001732.jpg Image:_4105421441.jpg Image:_4101104143.jpg Image:_4020354321.jpg Image:_3503184291.jpg Image:_3423803472.jpg Image:_3340040030.jpg Image:_3322208443.jpg Image:_3262211318.jpg Image:_3240344441.jpg Image:_3213207244.jpg Image:_3201343141.jpg Image:_3106320831.jpg Image:_3060318303.jpg Image:_3024322240.jpg Image:_2933120332.jpg Image:_2504132239.jpg Image:_2461325223.jpg Image:_2413204214.jpg Image:_2392310111.jpg Image:_2304094416.jpg Image:_2183228336.jpg Image:_2144023701.jpg Image:_2133577056.jpg Image:_2040434233.jpg Image:_2032741081.jpg Image:_1930461421.jpg Image:_1520212141.jpg Image:_1441070312.jpg Image:_1432481432.jpg Image:_1431146004.jpg Image:_1412035567.jpg Image:_1332755825.jpg Image:_1323415004.jpg Image:_1223223012.jpg Image:_1221460314.jpg Image:_1210024472.jpg </gallery> 417c29f7ba98300c354c75167625adcf34eac744 0 1 2481 2199 2014-01-03T00:19:32Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Images of [[Ed Wesly's Plate Boxes]], many, many plate boxes. * [[DCG Color Tuning]] guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the [[Gallery]]. * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the [[Reading Room]]. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 64b5a2316e7557c566c34cb2ae71259ad4c8922d 2482 2481 2014-01-03T00:20:32Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} http://holoforum.org/forum is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Images of '''[[Ed Wesly's Plate Boxes]]''', many, many plate boxes. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the '''[[Reading Room]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] ed99dcd27d655444823db0f2d59ff87725b917d1 2488 2482 2014-01-04T01:42:00Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Images of '''[[Ed Wesly's Plate Boxes]]''', many, many plate boxes. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the '''[[Reading Room]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] b05d2695d4086fa4ab431b4669968ecaea12896d 2491 2488 2014-01-27T03:36:22Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note| '''''The Holoforum site is temporarily unavailable. Hopefully, the problem will be remedied quickly.'''''| Gotcha}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Images of '''[[Ed Wesly's Plate Boxes]]''', many, many plate boxes. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the '''[[Reading Room]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] f8eef6f15018fc3f897ef5071d88fa4f4e6eaef0 2492 2491 2014-01-27T03:37:03Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note| '''''The Holoforum site is temporarily unavailable. Hopefully, the problem will be remedied quickly.'''''| error}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Images of '''[[Ed Wesly's Plate Boxes]]''', many, many plate boxes. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the '''[[Reading Room]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 2a9f73ed73bfbc978f85636f272c0ec5f1b0e0c5 2493 2492 2014-01-29T17:04:05Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Images of '''[[Ed Wesly's Plate Boxes]]''', many, many plate boxes. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. * Ed Wesly's ''The Seven Deadly Aberrations'' paper has been added to the '''[[Reading Room]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] b05d2695d4086fa4ab431b4669968ecaea12896d 2521 2493 2014-02-19T02:46:54Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * Images of '''[[Ed Wesly's Plate Boxes]]''', many, many plate boxes. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 18eacbcc6e5a984bfcf68139849c49f476a6b1ce 0 952 2486 2320 2014-01-03T03:31:17Z Jsfisher 1 wikitext text/x-wiki The following pages were derived from Ed Wesly's web pages at http://nlutie.net/ewesly. = Hologrammy = {| |- | * [[Ewesly / Holographic Pedagogy | Holographic Pedagogy]] * [[Ewesly / Holographic R&D | Holographic R&D]] * [[Ewesly / Holographic Artwork | Holographic Artwork]] * [[Ewesly / Holographic Formulae | Holographic Formulae]] * [[Ewesly / Publications | Publications]] * [[Ewesly / Holographic Consumer Reports | Holographic Consumer Reports]] | [[Image:WinterWonderlandCsm.jpg|right]] |} 445c3faad9431ff968b9875e7c49de2ccb300a35 0 1063 2487 2336 2014-01-03T03:38:05Z Jsfisher 1 /* Notes and References */ wikitext text/x-wiki == Developer == <p><u>PART A<strong></strong></u><br /> 20 g&nbsp; Catechol<br /> 10 g&nbsp; Ascorbic Acid&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br /> 10 g&nbsp; Sodium Sulfite&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br /> 50 g&nbsp; Urea<br /> One litre water</p> <p><u>PART B</u><br /> 60 g&nbsp; Sodium Carbonate<br /> One litre water</p> <p>Mix equal parts together before use.</p> === Development time === Reflection holograms: One minute for films, two for plates.<br /> Transmission holograms: Two to four minutes. <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<u>&nbsp;Agitation:</u>&nbsp; Constant</p> === Primary recommendation === For developing the discontinued Agfa Holotest 8E56HD and 8E75HD films and plates.&nbsp; Follow with a rehalogenating/diffusing bleach for no emulsion shrinkage, or 'Chrome bleach for change of replay wavelength in the reflection mode.&nbsp; Works well on Slavich PFG-01 plates and Fuji films.&nbsp; Also useful for processing Bulgarian Academy of Sciences HP-490 Holographic plates. === Shelf life === Part A can last a month in a tightly stoppered bottle; Part B can last indefinitely.&nbsp; The combined solutions can last at least a day in a covered tray.</p> == Notes and References == <p>[[Media:CWC2.PDF | D. J. Cooke and A. A. Ward, "Reflection-Hologram Processing for High Efficiency in Silver-Halide Emulsions," Applied Optics 23, 973 (1984)]].</p> <p>Although '''[[Media:CWC2g.pdf | I wrote this]]''' a long time ago, I just recently illustrated it with examples of the test strips. The Agfa 8E75HD plates mentioned are long gone, but the developer is still used, and the descriptions of the process and the methodology of testing are still sound. It's a 14 page PDF, so it will take a while to download, but worth it. Some of the stuff mentioned in the footnotes might pop up on this site in the future. bc2ecb665802b055df29d567b0a88888d466db0c 0 845 2489 1781 2014-01-05T03:39:32Z Jsfisher 1 wikitext text/x-wiki ==Phase materials for HOE applications== Richard D. Rallison<br>Ralcon Development Lab, Box 142, Paradise UT, 84328<br>ph (435) 245 4623, fax 6672, e/mail rdr@ralcon.com The choice of a phase recording material strongly affects the utility of the final recording. For display holograms properties like brightness, contrast, color range and color saturation might dominate and the choices are part art and part science. For HOEs, the extended range of properties that may require manipulation and the choices of materials to obtain each property in the required quantity, makes a working knowledge of what can be done extremely useful. This paper presents the fundamental properties of phase recordings and the fundamental properties of many phase materials so that a choice that will get a person from plan to product can be more readily made. Recipes are not given but references to recipes are and modifications or procedures that can modify a well known material may be described. The object of this paper is to make the reader aware of both the strong functions of these materials and the weak or subtle properties so that a design may be reviewed for feasibility a little more thoroughly and hopefully the route to a functioning product will be shorter and less costly. ==Introduction== The phase recordings we will consider are the simple transmissive sinusoidal volume plane grating, the powered or focusing volume grating, the general reflective volume grating with the two special cases of a conformal reflection recording and a strong spherical wave recording and finally the large class of surface phase gratings so popular because of the supposed ease of fabrication. We first identify as many of the properties of these phase structures as we can, then discuss the variations and mix of these properties that may be required in a well functioning final copy. At this point we define the minimum performance required of the end product and then list some popular media to choose from. In order to make a good first choice we need to know the intrinsic properties of these materials and their limitations, strong and weak points, cost, availability and perhaps what would be termed their "nuisance factor". This last factor is the reason I end up with plenty of work to keep me busy. Very often the art gets in the way of the science, the recipe has too many variables, the learning curve is a little too long and the literature a little too short and probably ambiguous and contradictory. We will use unscaled illustrations as much as possible and keep things as simple as possible, steering clear of any exhaustive validations of claims made for different materials or the chemistry involved. The reference material can be used to satisfy these other needs. Only simple algebraic equations or approximations are used without formal justification. ==Basic phase diffracting structures== Each of the figures 1 through 5 represent a common spatial phase modulator. The simple plane grating covers a wide terrain, wide enough to include transmissive display holograms made in bleached silver grain films which can be thought of as being made up of very many superposed plane gratings or as many tiny spatially multiplexed gratings. The reflective grating covers just about everything else that could be made but we have to consider the subtleties of various configurations and some special cases. Surface phase gratings are not just thin volume gratings, they have become a large class of optics themselves, referred to as diffractive optics (DOEs) and they enjoy considerable popularity at the present time. Some materials in common use today can be used to fabricate all of these diffraction structures, but none will cover all possible constructions within every class. Within the description of the properties of the HOE that is to be fabricated is the description of the material that will have to exist to make it. In most cases the material does exist and may be available in some form, but not always on the right substrate and in the right thickness. In real materials the direction that light transits through the HOE makes a difference, sometimes a large difference, the efficiency of a grating can actually be greater in one direction because of gradients in the modulation and holographic mirrors often reflect different spectra on each side with different intensities. ===Basic transmissive volume holographic gratings.=== Fig 1. Depicts an edge view of a section of a plane grating of thickness (T) of fringe spacing (d), at the surface and of fringe tilt or Brag tilt (B). The fringes themselves are regions of hi and low index (n) with the differences referred to as (Δn). The product of ΔnT is the total modulation of the grating but the diffracted light in each order also depends on angles a and b and wavelength (λ) which together define d. The change in index is usually not uniform through the film. It is common wisdom that the thicker the grating, the narrower is the angular bandwidth and the better is the suppression of higher orders, if they can exist. The other half of that assumption is that the value of Δn is small enough to make the product of ΔnT just large enough to diffract all of the light. If in fact the product is 2 or 3 times that high, the grating will behave as a 3 or 4 times thinner grating. Materials that require wet processing almost always have a gradient in index that can be very high, further reducing the effective thickness of the grating. Even real time recording materials, including photorefractive crystals have a gradient in index from absorption and behave as if they were much thinner than they are. The power lost to higher orders is proportional to Δn² so if modulation is excessive then not only is a thick grating rendered thin but it may diffract most of the incident power into useless orders. Another gotcha in dealing with thick gratings is the wandering Brag tilt B. Whenever wet processing is used there is a high probability that the original tilt made during exposure will play back at some other angle. In very thick gratings this error can exceed the angular bandwidth of the grating and render a non uniform grating that is useless. Thick gratings made in low shrinkage photopolymers and photocrosslinkers that require no processing seem to work well enough. If the intended use of the grating requires a thin structure with a broad angular and spectral response then the angles must be chosen so that higher orders cannot exist. This can begin when a and b both equal 30 degrees and the 2nd order becomes evanescent at 90 degrees (in air). The -1 order may still exist but is not entitled to receive much power at modulation levels near optimum for 99% diffraction efficiency (DE). When any of these gratings show excessive B error there is usually a preexposure fix that can be done to compensate or a post processing bake down or swell up for each material. A special case of this grating is the total internal reflection (TIR) geometry that requires extreme control over fringe tilt error. It should also be remembered that TIR gratings will not diffract P polarized light very well or at all for the same reason that Brewster's angle works. [[File:phasefig1.gif|Figure 1 Image]] '''Figure 1.''' The simple plane volume phase grating with properties: # sin a + sin b = λ/d # DE is proportional to sin²(ΔnT) and to 1/λ cos a + cos b) # Power lost to higher orders is proportional to Δn² # Fringe or Brag tilt B is proportional to T and n Figure 2 shows a common variance on a plane grating, a grating with a spatially varying spatial frequency such that rays of a certain λ and a common input direction will be diffracted to a common point on the output side. We may have seen this in text books as an off axis equivalent lens which is generally assumed to be a practical application of holography. For the fast optic shown, the output could be a family of points, half of them virtual and half real and all related geometrically to the fundamental focal length. Note that from top to bottom the spatial frequency (f₀ = 1/d) varies from very low, perhaps 200 l/mm to very high, perhaps 2000 l/mm. In the plane grating we only had to consider the modulation product of nT but now we have to add the term f₀ which also modifies DE. Note also that higher orders are nearly impossible to suppress at the top of this HOE and are nonexistent at the bottom. How would you ever make this design work? What material could be used? The difference in spatial frequencies could be compensated for in most materials by adjusting exposure energies in some way so that the lower end received less exposure and so create lower modulation than the top. This would solve the modulation balance except that now even more energy will be lost in the higher orders for only a small gain in the +1 because the losses at the top are proportional Δn², which just went up. Then perhaps the better fix is to try to keep n constant and vary the T from top to bottom such that the product of ΔnTf₀ is everywhere the same. Obviously you cannot buy such a material commercially so this special coating is very experimental. The processing will also have to be tailored because it is not likely that the thicker portions can be processed in the same time frames as the thinner portions. What about real time materials that saturate? Perhaps if available in liquid form, this HOE could be made. As the f# goes to 2.5 or higher this lens becomes a fairly good performer in most materials, only the really fast f#1 and lower optics are an art to construct and are probably best made in pieces if possible. An on axis lens made in any volume material at any f# will have a dead zone in the middle where almost no light can be diffracted because the spatial frequency falls to zero. One way around this dilemma is to work with a material that forms a surface phase structure at low spatial frequencies so that the HOE transitions from a surface phase HOE in the center to a thin and then thick phase HOE as the radial distance increases. A few materials will do this to some degree. [[File:phasefig2.gif|Figure 2 Image]] '''Figure 2.''' The case of a fast off axis focusing HOE with these additional properties: # DE varies from top to bottom if ΔnT is a constant. # Bragg or fringe tilt error is typically not uniform. # Higher orders often rob power from regions of large d spacing such as near the top. # S + P (random polarization) efficiencies cannot be as high at the bottom as in the middle. Figure 3 depicts a simple slanted reflection grating, if it were unslanted we would call it a conformal mirror with about the same properties found in dielectric stack mirrors. All reflection HOEs share one advantage over all transmission HOEs, the efficiency just keeps going up with increasing modulation rather than cycling up and down. The suppression of higher orders is also better at high n but the fringe spacing is a new variable affecting color and fringe tilt and it is nearly impossible to record an off axis reflection HOE without also recording a fairly strong transmission HOE. The idea of suppressing the unwanted transmission HOE by somehow index matching it out is only wishful thinking. The plane where the fringes meet the substrate must necessarily contain the same periodic changes in index that makes the HOE efficient, so the only case where a transmission HOE is not formed is the special case of the conformal reflector. This effect is of course minimized in materials of low n that rely on significant T to get sufficient modulation. In an HUD design the surface grating produces serious flare light when flying at certain angles to the sun, for that reason alone, practically all holographic HUDs are conformal reflectors. [[File:phasefig3.gif|Figure 3 Image]] '''Figure 3.''' The simple reflection grating with the properties: # DE is proportional to ΔnT. # λ is proportional to nT + any gradient in d spacing. # Δλ is proportional to Δn + any gradient in d spacing. # Surface grating strength is always non zero except for a conformal reflector. # power lost to -1 and higher orders is usually negligible even at high Δn Figure 4 is an illustration of a fast focusing reflection HOE. In this case the surface grating changes from high to low frequency but the reflection grating is more or less constant everywhere so that the efficiency is high every where. The efficiency falls off for P polarized light when the internal angle of diffraction or reflection approaches 90 degrees so if this is important to the design a denser material would be better than a less dense material. As the average n (roughly equivalent to density) of the film falls to low values the internal diffraction angles grow larger and account for many HOE failures. One of the errors this geometry is prone to is a variable fringe spacing and tilt induced by processing. Occasionally the distortion in the fringe structure is so large that constructive wave coupling fails and the HOE loses nearly all efficiency in spite of a large modulation level. Often the color is variable across the surface indicating a non uniform internal d spacing or average n. Hoes exhibit more severe aberrations in the reflection mode compared to the transmission mode, much like conventional optics. The choice of materials and processes to control them is particularly important when designing reflection optics or reflection art work. Full color display films have to have the required sensitometric characteristics as well as true reconstruction characteristics and only a few do. There are none that do it all with high efficiency but that is not a show stopper for anything but multi-wavelength notch filters and such which can usually be made with some other material. [[File:phasefig4.gif|Figure 4 Image]] '''Figure 4.''' The very fast non conformal reflection HOE with the properties: # DE is proportional to ΔnT # λ may vary with position from process induced distortions. # Surface grating can be very intense, producing a "transflection hologram." # Higher orders are suppressed much better than in transmission equivalent with mirror backing. ===Surface phase recordings.=== Figure 5 is a representation of the surface profiles common to diffractive optics, each has been recorded in one or more phase materials and copied in many more phase materials. The single biggest advantage of surface phase structures is that they can be replicated in a dozen or more ways that do not involve the use of lasers. In fact many are made as originals without laser light or at least without interference effects. Since they can often be made optically with lasers we have to consider them and mention the common materials with their properties and uses. The three most common surface profiles are shown as sinusoidal, square and sawtooth. The sinusoidal are natural continuous phase interference patterns, the square waves could be made by interfering a lot of odd harmonics in phase but are better copied from masks generated in typeset machines or on chrome masks exposed to E-beams. The sawtooth is deeper and is sort of the equivalent to a single side band transmitter with a suppressed carrier. This shape or its interferometric equivalent which appears more rounded is the only one that puts nearly all the light into one order. An exception to this is the deep square or sinusoidal grating that is high enough in spatial frequency to have no possible higher orders and is deep enough to have some volume type wave coupled interaction that results in high efficiency. The sawtooth shape has long been machined into materials to form blazed gratings for spectroscopy and now diamond turned blazed zone plates have become common on plastic lenses where the hybrid is effectively color corrected and has reduced spherical aberration. The blazed zone plate may also be made with a single exposure through a gray scale mask in photo-resist, in some photopolymers and with lesser performance in silver grain and DCG films. It is also made in the stepped mask manner where a multilevel stair case approximation to a blaze is achieve by using from 2 to 4 masks in sequence to expose the resist. This method is limited by mask resolution and alignment and by the wavelength of light used. If the grey scale mask or its binary equivalent can be used then it is only a one step exposure limited only by the mask resolution. This general class of optics includes binary optics, embossed rainbow holograms, embossed full parallax holograms, kinoforms and all other DOEs that are not volume HOEs (VHOES). [[File:phasefig5.gif|Figure 5 Image]] '''Figure 5.''' The general surface phase structure with the properties: # Angular bandwidth (Δθ) is much larger than in volume holograms or VHOEs. # Power distribution in higher orders is a strong function of fringe shape and depth T. # T is roughly equivalent to Δn and depends on n, except for metalized reflective shapes where air is the phase shifter. # Computer generated DOEs, lithographic or machined, are now common and practical, HOEs still rule at high f₀,(pun intended). ==Matching materials== The broadest class of phase recording materials would fill a book or two so we only want to consider generic silver grain films, DCG, Polaroid photopolymers, Dupont photopolymers, PVA, PVK and Shipley photo-resist. Reference texts and papers are listed in the bibliography for recipes and other details. The new book edited by Hans Bjelkagen entitled Holographic Recording Materials is the most comprehensive single source for valuable practical material information. It is a milestone series containing 676 previously published papers covering all but PVK and PVA. Many of the papers listed separately in my bibliography are in his book. ===Silver-Halide in gelatin=== By far the most popular materials to work in are products from Agfa, Kodak and a handful of smaller producers around the world. Some are panchromatic, some have extremely fine grains, all are comparatively fast and a few have been made to work in the near IR. They are the first choice of most artists because of the sensitivity to commonly available lasers of all colors and because they may be repeatably exposed and processed to produce the widest range of visual effects. The upper range of n is on the order of .1 and the grain size varies from a low of about 10 nm to over 100 nm. Grains are a significant source of scatter and therefore produce noise in the recordings, especially at short wavelengths. This is a major consideration for most applications and for all but the smallest grain films. Just about any HOE and some DOEs may be made in silver films but they will rarely be optimized for any enough properties and if they are bleached to get the highest efficiency then other sources of noise begin contributing and grain size may grow as well. A well worked out plan for a product may utilize the speed and panchromatic properties to produce a master HOE that can then be contact copied into a material with appropriate final properties. These films can be left as clean amplitude holograms or converted to "no silver halide in gelatin" (SHG) with simple chemistry and the resultant optic will be free from scatter caused by the grains of silver. The SHG masters are especially good when copying in the blue region where the lower n works well and silver grains often produce excessive noise. A good example is the making of a HOE like figure 2 that must perform well at 680 nm. If it were made at any other wavelength than 680 it would play back with aberrations so we either have to precompensate for those aberrations or make a master at 680 nm. Both Agfa and Kodak make films that are sensitive to 680 nm and that can also readily be processed into SHG masters with a simple weak chrome bleach followed by a fix and some hot alcohol baths. Then the master can be copied at 488 into DCG or a suitable photopolymer or the much slower photo-resist. Display masters may also be made this way, taking advantage of the speed of silver (as low as 3 µj/cm²) and then creating a photo-resist submaster in a more stable set up using 442 nm light. Contact copies of even a weak hologram can be very bright when transferred to DCG provided that the ratio of reference to object light is no less than 10:1 at the bright points and the scatter from all sources is very low. We highly recommend this general procedure for any exposures that have to be made at wavelengths longer than 514 nm to about 750 nm. Diode lasers can easily be made to operate in a single mode for long enough to make a good recording and Ion lasers or cadmium lasers can do all the copying. ===DCG (dichromated gelatin)=== By far the most versatile of the phase materials, DCG in its simplest form can be used to create almost any type of HOE as long as the exposure is allowed to be done at blue green or shorter wavelengths. A few people have even made good quality HOEs with dye sensitized DCG aka DSDCG, using krypton red or big HeNe lasers. The disadvantage there is the low sensitivity of the material and low availability of strong red sources. DSDCG may require from 50 to 1000 mj/cm² @ 647 nm while DCG can be used with as little as 4 mj/cm² @ 442 nm to about 100 mj/cm² @ 514 nm. In general all the photopolymers and all the photocrosslinkers are at least 1000 times less sensitive than silver halide products. We are fortunate that low scatter can be had from both mediums or else copying from one to the other would be useless. The intrinsic noise from a highly efficient DCG HOE of moderate thickness in the 5 to 8 micron range is 1 or 2%, a very low number. The sources of noise can be controlled to that level for simple grating like structures but surface noise from dirty beams, intermodulation noise found in multi-beam or diffuse object recordings, dust on and in the film and nonlinearity noise through the bulk can all contribute to the best of the materials and not all noise sources can be eliminated. The two greatest advantages of using DCG are the intrinsic low scatter, (if hardened sufficiently), and the tolerance for many reprocessing or post processing steps to fine tune the end product. The biggest disadvantage is that you have to devote time and space to a clean coating facility and the end product is extremely sensitive to high humidity. Some products require a careful tailoring of the thickness and juggling of the sensitizer and in those cases the requirement to coat your own is a big advantage. We work with standardized mixtures and coating methods that produce 5, 8, 10 and 25 micron thick coatings that have been sufficient to make almost any HOE for the visible and near IR regions, from 450 to 1500 nm. When the material is used without much hardening it produces hazy holograms that exhibit broad spectral and angular bands but as it is hardened it also narrows and at some point it crosses into the no scatter zone quite suddenly, with no attendant change in other properties. This point is where even unexposed gelatin can no longer be dissolved out with warm water, leaving scattering centers behind. At all levels of hardness the Δn near the surface can be pushed to .25 but as in most other media that number can not be extrapolated to thicker films. Films as thick as 100 microns have been made and processed but they behave no differently than 50 micron films which in turn behave thicker than 25 micron films but have a ΔnT product that is actually lower than what is achievable at 25 microns. We think 25 to 30 microns is about the practical limit for HOEs made in DCG, which means notch filters made in DCG can trade off bandwidth for density up to that thickness but top out at a ΔnT product of about 2.5, no matter how thick or thin the film is. DMP-128 from Polaroid tops out at about 2 also, bleached silver film is about .7, PVA is about .8 after wet processing and dupont products go to at least to 1. DCG has been used successfully with all the basic configurations, including the surface relief structures. For spatial frequencies below 500 l/mm DCG and silver halide films both form efficient surface relief profiles. This works best with softer gelatin and in silver film is enhanced by repeated bleach and develop steps. In DCG the effect is enhanced by using thick film and a longer soak in a .86 SG alcohol and water mixture before final dehydration in straight alcohol. Fixing after the first processing can improve the gel hardness without destroying the relief image and then the gel can be used as an embossing master with solvent softened plastics. Hardened silver halide films work about as well. The problems related to non uniform spatial frequencies or just non uniform exposures can be fixed if they are only off by 10 or 20% by post processing DCG in baths of hot soapy water and in fixer where areas that require more modulation are dipped in hot water and areas that are too well done can be brought down with fixer. Local zones may be repeatedly painted with fixer or a 5% solution of TEA and then reprocessed in water and alcohol to balance out the plate. If an area is known to be over exposed before processing, it may be effectively unexposed with an ordinary incandescent light bulb held close to it for a few minutes. All of these manipulation methods are experimental and the rules are loose and vary greatly from thick to thin in time and intensity. Baking at about 150 C will cause the gelatin to densify and if tilted fringes are present they will appear to lay down, baking also makes the gel much more stable and a little less hygroscopic. While it is still hot a glass cap or at least an epoxy coating can be applied without trapping too much moisture in the film. Trapped moisture can become active upon heating and cause the gel to collapse here and there and everywhere. Mysterious color shifts in capped reflection holograms can be explained by the action of trapped moisture and lack of 150 bake down. The sensitivity to moisture is not the only drawback to using DCG. It will easily distort in thick films and in large area recordings in thin films it is very difficult to process uniformly. The processing leaves the fringe planes at slightly random positions and usually the film expands so that the fringes stand up while the bulk n goes down. In gratings made at near 64 degrees in and out for either reflection or transmission the diffraction efficiency for incident P polarized light is near zero, because n has dropped to about 1.3. Unless you were building a polarization separator you would not find this desirable. In fact the low n means that the difference between S and P efficiencies is always larger than in more dense media. DMP-128 also has a low average n for about the same reason, the Δn is created by producing low density voids in the film during dehydration, much like the making of aerogels. ===DMP-128 photopolymer from Polaroid=== This film has enjoyed success as a flexible film used for great looking reflection and transmission display holograms. It is also useful for making high density reflectors and because of the unique open structure it can be filled with liquid crystals to make disappearing HOEs and DFB lasers and narrowband filters. It is easier to stabilize than DCG and has about the same high modulation in films of 7 to 15 microns. All of the wet processed films seem to work best in the thickness range of from 5 to 15 microns, probably owing to limited diffusion rates in DCG and in DMP-128. This material is used mostly with red light but can be made panchromatic more easily than DCG and is much more sensitive, requiring only about 25 mj/cm² to fully expose. This material is saturable, once the polymerizeable material is used up the effects of exposure are nil. This is a great advantage in production because over exposure has almost no effect, except to maybe compress the contrast range a little. This is true of all the migratory photopolymer systems, including all of Dupont's photopolymer products. The light used to expose the hologram need not be perfectly uniform to get a uniform copy. The ratio of the reference to object wave is the primary determinant of how much modulation an area will have after an over exposure. It is a sort of self "dodging" film with a hard limit on modulation related to beam ratio. This implies that to get maximum performance a reflection or transmission master has to be as bright in its hot spots as the reference. One disadvantage of this material is that it is on a substrate that has a higher index than the unexposed film so that all recordings have a mirror in them and the film is not generally available in liquid form as of this writing. Environmental controls are important at the exposure station, because the film has to be activated by a fairly precise percentage of water or it will produce noisy holograms. The low average n may be a disadvantage for some HOES and the material tends to shrink during or after processing and needs to be babied a little to get it to reconstruct with perfect fidelity. The display holograms are the best and brightest among the mass produced products and last a very long time. Polaroid has announced the introduction of another photopolymer that also has a high n but needs no wet processing and therefore is much more suitable for precision HOE making. It will be a great boon to some of us if they market the film as Dupont does, coated and in liquid form. I don't have a clue about how it is used or how well it performs. Photopolymers, because of the dynamics of monomer migration, may make pretty poor sequential hologram recordings, each successive shot adds noise to the previous shot, and if angles are not changed sufficiently between shots in a real time material then more than one recording will be made at a time as previous recordings reconstruct and rerecord with new ones. Latent image recordings do not have this problem and some real time materials do not have migration occurring. The little things can get you. ===Dupont Photopolymers=== These are all real time recording materials with migration of monomer. They work as is or may be enhanced with post exposure baking and with the addition of a monomer to swell them to a thicker state. Swelling shifts playback color and angle in reflection holograms. The sensitivity of some films is down to a few mj/cm² but as with DMP-128 they cannot be over exposed. Some films are panchromatic and good full color holograms can be made in them. The available Δn is about .06 on a good day in the best of films so to get good brightness the films are over 8 microns thick, more typically about 20 microns. They play back with smaller bandwidths but look clear in about any light. The normal backing is mylar and is birefringent causing some problems with production and making it difficult to make HOEs with high integrity. The liquid film has been made available so that it can go on glass and then good quality HOEs are possible. A very large number of display holograms have been produced in this material, which is sold in sheets and rolls with machines to expose and process it. The limited modulation prevents this material from being used in some tasks, but it is a big plus for others. When high angular selectivity or a narrow notch filter is needed it is the material of choice, especially if you can get coatings of 50 microns or more. Optical memories have been made with it and could flourish. We made diffraction limited gratings with it. The dye never bleaches all the way out of some of their films so it is useless at short wavelengths, as is DCG and PVK. Most if not all holographic recording materials naturally absorb strongly in the UV region both long and shortwave. One of Dupont's materials forms an excellent embossed surface upon exposure and is great for copying binary or possibly shaded masks. The shading may copy with poor linearity depending on light intensities, spatial frequencies and migration rates and distances, all considerations that could spoil your day. We copied a binary mask in non embossing material and found that it was self guiding because of the real time formation of the higher index light fringes. The first light through the slits forms a guide for the rest and the usual diffractive spreading does not occur and the copied HOE is excellent except for the plastic substrate it is usually on. This is very easily used material, and stores for years in a fridge. ===PVA and PVK=== PVA (polyvinyl alcohol) has been dichromated and used as a real time material fixed with heat for many years. It is easy to get, mix, coat and use this way. It is also possible to enhance the modulation greatly by dipping it in water and alcohol, similar to DCG processes. It can also serve as a binder for a monomer and act more like other photopolymers. In its dichromated form it is a photocrosslinker like DCG and as such has no migration but the latent image in PVA is many times better than the latent image in DCG. Images and HOES are easily seen as they form in films as thin as 5 microns. The integrity of the recordings is very high with very little damage done by overwriting multiple times. As a crosslinker it is not a saturable media and can be overexposed, however it requires about a 100 mJ/cm² to form a strong recording and about 1000 more to begin to undo it. One disadvantage is that it does not adhere well to glass or plastic which makes it a perfect candidate for a transfer hologram. It is possible to form a conformal mirror in it on flat glass or plastic in a production environment and then lift it off and transfer it to a spherical surface in another off line process. It is soluble in water and unstable at high humidity but it may be possible to stabilize chemically by converting at least some of its molecules back into polyvinyl acetate or by adding crosslinking agents to a last bath. Borax is used to crosslink PVA and form "slime", baking a wet processed PVA hologram causes it to return to its original latent image state and stabilizes it somewhat against moisture. Other uses include protecting and cleaning optics and it is a common mold release agent. PVK (polyvinyl carbazole) is not soluble in water but dissolves in chloroform and in sensitized by halogens to become a photocrosslinker. It is processed in xylene and hexanes or a mono bath of miscible but differentially volatile solvents. It should only be used where maximum resistance to water is needed. It will work well in 5 micron layers, has a short shelf life and a high Δn but is hard to process uniformly. It is sensitive to blue green light and requires only a few mJ/cm². It requires the use of noxious chemicals, some of which are known carcinogens. PVK is also a commonly used photoconductor which could be used to form relief holograms in thermoplastics and for light intensifiers. If used for holography it has to be sensitized at the same time it is dissolved or it will not work, the fastest sensitizer is carbon tetra iodide and it is extremely unstable. ===Shipley Photo-resist=== Many of us use this as a standard for embossing masters. It can be obtained on plates commercially from several sources, has a long shelf life, and reasonable sensitivity to blue and UV light. We have jars of material that are 20 years old and still work about as well as they ever did. This is the most common material used to make binary optics from metal masks and it is easily metalized for production of embossing shims. We make masters from epoxy molds lifted from the resist and then mold copies in other epoxies and plastics. It is possible to make features as deep as 4 or 5 microns with little effort and resist masters may be directly converted to glass masters with reactive ion etching or with diluted HF. Some people are able to get very high aspect ratios in it and form high frequency high efficiency gratings in it. The integrity of the recording is rarely compromised in processing, but very high frequency gratings may close over at the top if the are exposed to common organic solvent fumes. Resist is user friendly and you never have to even dim the lights while working with it. All surface phase DOEs and HOEs are readily made in this material. It is often advisable to make a clean master in DCG to copy from because the exposures for reasonable sizes copies can run from several minutes to an hour, during which time a contact copy on three legs may not move but most optical setups of any size will. The required exposure is on the order of 2000 mJ/cm² @ 488 nm. Clean glass and primers and bakeouts are sometimes necessary to keep the resist on the glass and since most resists used are positive, exposure to UV after processing will break bonds and leave the material prone to falling off when you least want it to. There is a lot more to be said about designs and materials but no more room or time to say it. ==Relative material sensitivities== [[File:delta_n.gif|Average Delta n 8 microns vs. Exposure Energy in mJ/cm²]] ==References== # H. Kogelnik, "Coupled wave theory for thick hologram gratings" <em>Bell Syst Tech J. </em> <strong>48</strong>:2909-2947 (1969) # T. K. Gaylord and M. G. Moharam, "Analysis and applications of Optical Diffraction by Gratings" <em>Proc. of IEEE</em>, <strong>73,</strong> (5) (May 1985). # J.N. Cederquist and J.R. Fienup,"Analytic Design of Optimum Holographic Optical Elements" <em>J Opt Soc Am A</em><strong>4</strong>:699-705 (April 1987) # E. Hasman and A.A. Friesem, "Analytic Optimization for Holographic Optical Elements". <em>J Opt Soc Am A</em><strong>6</strong>:62-72 (Jan 1989) # F. T. S. Yu. "Effect of Emulsion Thickness Variations on Wavefront Reconstruction". <em>App Optics</em><strong>10</strong>:1324-1328 (June 1971) # R. D. Rallison "Incoherent Multifocus Hololens design and fabrication", <em>Proc. SPIE </em><strong>1183</strong>:663-668 (1989) # M. Chang and N. George, "Holographic Dielectric Grating; Theory and Practice" bibliog diags <em>Ap Optics</em><strong>9</strong>:713-719 (March 1970) # T.K. Gaylord and F. K. Tittel, "Angular Selectivity of Lithium Niobate Volume Holograms",<em> J. App Phys</em> <strong>44</strong>: 4771-4773 (Oct 1973) # J.N. Latta, "Computer-Based Analysis of Hologram Imagery and Aberrations", <em>Ap Optics</em> <strong>10</strong>:599-618 (Mar 1971) # Y. Amitai et al "Holographic Elements with High Efficiency and Low Aberrations for Helmet Displays", <em>Appl Opt </em><strong>28</strong>:3405-3416 (Aug 15 1989) # Y. Ono and N. Nishida "Holographic Zone Plates for f'0 and Collimating Lenses", <em>Appl Opt</em> <strong>25</strong>:794-797 (Mar. 1986) # J.R. Fienup "Iterative Method Applied to Image Reconstruction and to Computer-Generated Holograms", <em>Opt Eng</em> <strong>19</strong>:297-305 (May 1980) # M.R. Latta and R.V. Pole "Design Techniques for Forming 488-nm Holographic lenses with Reconstruction at 633 nm", <em>App Opt </em><strong>18</strong>:2418-2421 (July 15 1979) # E. Wihardjo, et al "Compensation of Wavelength-Shift Aberrations in an off-axis Holographic Zone Plate", <em>Opt Eng</em> <strong>25</strong>:871-874 (July 1986) # <em>Holographic Optics: Design &amp; Applications. </em>Cindrich, ed<em>. SPIE press</em> (1988). # R.C. Fairchild and J.R. Fienup, "Computer Originated Aspheric Holographic Optical Elements", <em>Opt Eng</em> <strong>21</strong>:133-140 (Jan/Feb 1982) # D. A.Winick, "Thick Phase Holograms", Environmental Research institute of Michigan, Level, (January 1981). # L. Solymar &amp; D.J. Cooke , <em>Volume Holography and Volume Gratings</em>, Academic Press, (1981). # Felix P. Shvartsman and Moshe Oren, "Photo-lithographic imaging of computer generated holographic optical elements" <em>Proc. SPIE <strong>1555</strong></em>:71-78, (1991). # A.J. Lee and D. P. Casasent,"Computer-Generated Hologram Recording Using a Laser Printer", <em>Appl Opt</em><strong>26</strong>:136-138 (Jan 1 1987) # Steven M. Arnold, "Desktop computer encoding of electron-beam written holograms" <em>Proc. SPIE </em><strong>884:</strong>23-27 1988. # R. D. Rallison , "Wavelength compensation by time reverse ray tracing", <em>Proc. SPIE </em><strong>2404</strong>: 217-225 (1995) # G. D. Mintz, D.K. Morland &amp; W.M. Boerner, "Holographic Simulation of Parabolic Mirrors", <em>Applied Optics,</em> <strong>14</strong> (3):564-570 (March 1975). # Hans Dieter Tholl "Polarization properties of volume phase gratings", Optical Engineering, <strong>34</strong>(10)2879-2885 (Oct 1995) # W. S. Colburn &amp; B. J. Chang "Holographic Combiners for Head-Up Displays", <em>Technical Report AFAL-TR-77-110</em> (Jan 1977). # Ryszard Gajewski "Holographic Technology for Solar Energy Concentration" <em>Technical Report No. 87-1479</em> (July 1984). # Jose R. Margarinos &amp;Daniel J Coleman "Holographic Mirrors" <em>Proc. SPIE </em> <strong>523</strong>:203-218 (1985). # Richard D.Rallison, "Holographic Optical Elements (HOES) in Dichromated Gelatin (DCG)", <em>Proc. SPIE</em> <strong> 523</strong>:292-295 (1985). # Jon D. Masso "Multilayer Thin Film Simulation of Volume Holograms" <em>Proc. SPIE</em> <strong>883</strong>:68-72 (1988). # H. M. Smith, <em>Holographic Recording Materials</em> Springer Verlag, 1977 # H. I. Bjelkhagen, <em>Silver-Halide Recording Materials for Holography</em>, Springer Verlag, 1995 # R. D. Rallison, "Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug.(1987) # T. A. Shankoff, "Phase holograms in dichromated gelatin" Appl. Opt. <strong>7:</strong>2101-2105 (1968) # Hans I Bjelkhagen, <em>Holographic Recording Materials</em>, SPIE publications, 1996. # R. D. Rallison "Survey of properties of volume holographic materials", <em>Proc. SPIE</em> <strong>1051</strong>:68-75 (1989) # J. L. Salter and M. F. Loeffler, "Comparison of dichromated gelatin and dupont HRF-700 photopolymer as media for holographic notch filters" <em>Proc. SPIE </em> <strong>1555</strong>:268-278 (July 1991) # R.A. Bartolini, "Characteristics of Relief Phase Holograms Recorded in Photoresists"<em>App Optics</em> <strong>13</strong>:129-139 (Jan 1974) # Tung H. Jeong, <em>Proceedings of the International Symposium on display holography,</em> Vol I (1983) # Tung H. Jeong, P<em>roceedings of the International Symposium on display holography</em> Vol II (1986) # D.J. Lanteigne and T.D. Hudson, "The DMP-128 Holographic Cookbook" Technical Report RD-RE-86-14 U.S. Army Missile Command, Nov. 1986. # J. C. Kirsch, D. J. Lanteigne and Don Gregory, "An investigation into DMP-128 Holographic Recording Material" Technical report RD-RE-87-1 U.S. Army Missile Command, Feb 1987. # D.H. Close and A. Graube, "Materials for Holographic Optical Elements", Technical Report AFML-TR-73-267, Oct. 1973. # B.J. Chang, "Post Processing of Developed Dichromated Gelatin Holograms", Opt Comm, <strong>17</strong> (3): 270-271 (June 1976). # T. Kubota, T. Ose, M. Sasake and K. Honda "Hologram Formation with Red Light in Methylene Blue Sensitized Dichromated Gelatin" <em>Applied Optics,</em> <strong>15</strong>(2):556-558 (Feb. 1976). # S.P. McGrew, "Color Control in Dichromated Gelatin Reflection Holograms", <em>Proc. SPIE </em><strong> 215</strong>:24-31 (1980). # R. T Ingwall, M Troll and W. T. Vetterling "Properties of Reflection Holograms Recorded in Polaroid's DMP-128 Plotopolymer" <em>Proc SPIE</em> <strong>747</strong>:67-73 (1987). # R. D. Rallison, "Control of DCG and non silver holographic materials" <em>Proc SPIE </em> <strong>1600</strong>: 26-37 (1991). ''Last modified on 9/16/97'' [[Category:Rallison]] 52dc35e740acfb808bd826eabb7368ff86ff059f 0 489 2490 2133 2014-01-05T04:13:52Z Jsfisher 1 wikitext text/x-wiki <DirList>docs</dirlist> http://abc.def.com/asdf Text <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} [[Sandbox / Subsandbox]] This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== [[User:Jsfisher|/jsfisher]] ([[User talk:Jsfisher|talk]]) 23:19, 25 June 2013 (EDT) ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y} scriptscriptstyle</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> 9b71779e86d1152866e58e33a745ceb8a566c0a6 0 1024 2494 2368 2014-02-19T01:51:03Z Jsfisher 1 /* Bleaches */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-1 Kit | JD-1 Kit]] * [[Ewesly / Holographic Formulae / JD-2 Kit | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Type listing == ==== Rehalogenating ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / JD-1 Kit | JD-1 Kit]] * [[Ewesly / Holographic Formulae / JD-2 Kit | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] </div> ==== Stain Remover ==== KODAK S-13 <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] d10ff451c103181df7896d899e51ff7f623bfd63 2495 2494 2014-02-19T01:51:46Z Jsfisher 1 /* Type listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-1 Kit | JD-1 Kit]] * [[Ewesly / Holographic Formulae / JD-2 Kit | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / JD-1 Kit | JD-1 Kit]] * [[Ewesly / Holographic Formulae / JD-2 Kit | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] </div> ==== Stain Remover ==== KODAK S-13 <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] b608307c40323f250979f01cc2207fed698c094b 2506 2495 2014-02-19T02:12:54Z Jsfisher 1 /* Bleaches */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pychrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / JD-2 Kit | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pychrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / JD-2 Kit | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] </div> ==== Stain Remover ==== KODAK S-13 <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 971fbf27fcaf61ff0495a2b689ad31708b834fae 2507 2506 2014-02-19T02:13:44Z Jsfisher 1 /* Bleaches */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / JD-2 Kit | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / JD-2 Kit | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] </div> ==== Stain Remover ==== KODAK S-13 <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 55e62a28e98d9676225f44c399cd0cb877a1ec50 2508 2507 2014-02-19T02:15:35Z Jsfisher 1 /* Bleaches */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Reversal | Reversal]] </div> ==== Stain Remover ==== KODAK S-13 <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] d769b948788d476936a5230f2ec967d4a02661fb 2519 2508 2014-02-19T02:28:05Z Jsfisher 1 /* Bleaches */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] </div> ==== Stain Remover ==== KODAK S-13 <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 4515d133d71952ae039ba891b774734c74b97955 2520 2519 2014-02-19T02:40:05Z Jsfisher 1 /* Stain Remover */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] </div> ==== Stain Remover ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] f2e7eaf0ebc3a0ac42e94f0b2e6ff879c9495e41 2522 2520 2014-02-19T02:48:14Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] </div> ==== Stain Remover ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] f9ac13e861e70b187ea47a28b7945f991fb4b9f7 0 1190 2496 2014-02-19T01:57:29Z Jsfisher 1 Created page with "== Bleach solution == === Original formula === 30 g&nbsp; Ferric Sulfate<br /> 30 g&nbsp; di-Sodium EDTA<br /> 30 g&nbsp; Potassium Bromide<br /> 10 ml Sulfuric Acid (..." wikitext text/x-wiki == Bleach solution == === Original formula === 30 g&nbsp; Ferric Sulfate<br /> 30 g&nbsp; di-Sodium EDTA<br /> 30 g&nbsp; Potassium Bromide<br /> 10 ml Sulfuric Acid (Conc.)<br /> One litre water === Revised formula === 30 g&nbsp; Ferric Sodium-EDTA<br /> 30 g&nbsp; Potassium Bromide<br /> 30 g&nbsp; Sodium Bisulfate<br /> One litre water === Processing === <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p><u>Shelf life:</u>&nbsp; Possibly years, as long as the plate is well-washed of developer before bleaching to avoid contamination.</p> <p>Less hazardous to work with than the dreaded PBQ.&nbsp; Either version of the recipe gives the same result, the choice depending on the price and availability of the ingredients.&nbsp; Leaving the solution exposed to air (uncovered tray) will extend the lifetime of the oxidizer.</p> <p><u>Source:</u>&nbsp; Nicholas Phillips, &quot;Benign Bleaching for Healthy Holography&quot;, holosphere, Volume 14, Number 4, p.21, (1986)</p> 535042deef3eae90b43d1b698c0f74bba35843ea 2498 2496 2014-02-19T02:01:33Z Jsfisher 1 wikitext text/x-wiki == Bleach solution == === Original formula === <p> 30 g&nbsp; Ferric Sulfate<br /> 30 g&nbsp; di-Sodium EDTA<br /> 30 g&nbsp; Potassium Bromide<br /> 10 ml Sulfuric Acid (Conc.)<br /> One litre water</p> === Revised formula === <p> 30 g&nbsp; Ferric Sodium-EDTA<br /> 30 g&nbsp; Potassium Bromide<br /> 30 g&nbsp; Sodium Bisulfate<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p><u>Shelf life:</u>&nbsp; Possibly years, as long as the plate is well-washed of developer before bleaching to avoid contamination.</p> <p>Less hazardous to work with than the dreaded PBQ.&nbsp; Either version of the recipe gives the same result, the choice depending on the price and availability of the ingredients.&nbsp; Leaving the solution exposed to air (uncovered tray) will extend the lifetime of the oxidizer.</p> <p><u>Source:</u>&nbsp; Nicholas Phillips, &quot;Benign Bleaching for Healthy Holography&quot;, holosphere, Volume 14, Number 4, p.21, (1986)</p> 99f41fc6b7901331d7372ae67e764a6af87bee9b 0 1191 2497 2014-02-19T02:00:41Z Jsfisher 1 Created page with "== Bleach solution == <p>4 g Potassium Dichromate<br /> 4mL Sulfuric Acid (or 12 g Sodium Bisulfate)<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u>Ti..." wikitext text/x-wiki == Bleach solution == <p>4 g Potassium Dichromate<br /> 4mL Sulfuric Acid (or 12 g Sodium Bisulfate)<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u>Time it takes to clear plus 15 seconds, not to exceed 2 minutes.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Constant</p> <p>Distilled water is recommended otherwise white scum may collect in the emulsion. First hologram in the bath may take a long time to clear. When clearing time exceeds two minutes the bath is becoming saturated with silver salts and needs to be replaced. Hanging the plate vertically in a tank or with emulsion side down in a tray during bleaching speeds the exit of the soluble silver salts from the emulsion.</p> <p> <u>Shelf life:</u> This solution stores indefinitely, but should be dumped when it takes longer than a couple of minutes to clear. Ilford SP679C is a packaged, concentrated version of this bleach.</p> <p><u>Source:</u>&nbsp;Walter Spierings, "'Pyrochrome' Processing Yields Color-Controlled Results with Silver-Halide Materials", holosphere Volume 10, Numbers 7 and 8, p.1, (1981)</p> <p><a href="../Developers/PYROAB.pdf" title="A revolution in its day!" target="_new">My ramble on The Process</a>.</p> 69dafd42559ca1a945b4f5a1f0b6bd0992635a07 0 1192 2499 2014-02-19T02:04:30Z Jsfisher 1 Created page with "== Bleach solution == <p>15 g Citric Acid<br /> 50 g Potassium Bromide<br /> 2 g p-Benzoquinone (PBQ) added just before use.<br /> One litre water</p> == Processing == <p>..." wikitext text/x-wiki == Bleach solution == <p>15 g Citric Acid<br /> 50 g Potassium Bromide<br /> 2 g p-Benzoquinone (PBQ) added just before use.<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<u>&nbsp;Agitation:</u>&nbsp; Intermittent<br /> </p> <p>Introduced with CWC2 developer. If you do not have good ventilation or a respirator, use one of the other rehalogenating formulas as the PBQ has a rather pungent odor. But if you take the proper precautions you will be rewarded.<br /> </p> <p><u>Primary recommendation</u> for bleaching the discontinued Agfa Holotest 8E56HD and 8E75HD films and plates.&nbsp; as there is no emulsion shrinkage, thanks to the tanning effect of the PBQ. Works well on Slavich PFG-01 plates and Fuji films.&nbsp; Also useful for processing Bulgarian Academy of Sciences HP-490 Holographic plates.</p> <p><u>Shelf life:</u>&nbsp; The acidified salt solution alone will last indefinitely; with PBQ added the bleach will need to be discarded at the end of the day. Keeping a lid on the developing tank or tray will extend the working life.</p> <p><u>Source:</u>&nbsp; D. J. Cooke and A. A. Ward, "Reflection-Hologram Processing for High Efficiency in Silver-Halide Emulsions," Applied Optics 23, 973 (1984).</p> <p>Although I wrote <a href="../Developers/CWC2g.pdf" title="CWC2 Reigns Supreme! (Back then)" target="_new">this</a> a long time ago, I just recently illustrated it with examples of the test strips. The Agfa 8E75HD plates mentioned are long gone, but the developer is still used, and the descriptions of the process and the methodology of testing are still sound. It's a 14 page PDF, so it will take a while to download, but worth it. Some of the stuff mentioned in the footnotes might pop up on this site in the future.</p> d498f16aadb571d2da25d5a3ff50beb60a44c6c7 0 1193 2500 2014-02-19T02:06:07Z Jsfisher 1 Created page with "== Bleach solution == <p>20 g Glycerol<br /> 500 ml Deionized Water<br /> 500 ml Isopropyl Alcohol<br /> 300 mg Phenosafranine<br /> 150 g Ferric Nitrate<br /> 33 g Pot..." wikitext text/x-wiki == Bleach solution == <p>20 g Glycerol<br /> 500 ml Deionized Water<br /> 500 ml Isopropyl Alcohol<br /> 300 mg Phenosafranine<br /> 150 g Ferric Nitrate<br /> 33 g Potassium Bromide<br /> One litre water</p> <p>Dilute 1 to 4 with water before use.</p> == Processing = <p><u>Bleaching time: </u>One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p>For rehalogenation after fixing. Hans Bjelkhagen prefers this over the simpler GP 431 formulation for pulsed masters developed in Neofin Blau diluted 1:1.<br /> </p> <p> <u>Shelf life:</u>&nbsp;This stock solution lasts indefinitely, working solution about one week. </p> <p><u>Source:</u>&nbsp;N. J. Phillips and D. Porter, &quot;An Advance in the Processing of Holograms,&quot; Journal of Physics E: Scientific Instruments 9, 631 (1976). </p> <p><a href="AgfaBrochure.PDF" title="More uselessness!" target="_self"></a></p> f40ef6d0a257917a7495f968abc5b9cb41f9864c 2501 2500 2014-02-19T02:06:21Z Jsfisher 1 wikitext text/x-wiki == Bleach solution == <p>20 g Glycerol<br /> 500 ml Deionized Water<br /> 500 ml Isopropyl Alcohol<br /> 300 mg Phenosafranine<br /> 150 g Ferric Nitrate<br /> 33 g Potassium Bromide<br /> One litre water</p> <p>Dilute 1 to 4 with water before use.</p> == Processing == <p><u>Bleaching time: </u>One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p>For rehalogenation after fixing. Hans Bjelkhagen prefers this over the simpler GP 431 formulation for pulsed masters developed in Neofin Blau diluted 1:1.<br /> </p> <p> <u>Shelf life:</u>&nbsp;This stock solution lasts indefinitely, working solution about one week. </p> <p><u>Source:</u>&nbsp;N. J. Phillips and D. Porter, &quot;An Advance in the Processing of Holograms,&quot; Journal of Physics E: Scientific Instruments 9, 631 (1976). </p> <p><a href="AgfaBrochure.PDF" title="More uselessness!" target="_self"></a></p> ee5b87c410e358b40821887eee97721898ac455b 0 1194 2502 2014-02-19T02:07:57Z Jsfisher 1 Created page with "== Bleach solution == <p> 300 mg Phenosafranine<br /> 150 g Ferric Nitrate<br /> 33 g Potassium Bromide<br /> One litre water</p> <p>Dilute 1 to 4 with water before..." wikitext text/x-wiki == Bleach solution == <p> 300 mg Phenosafranine<br /> 150 g Ferric Nitrate<br /> 33 g Potassium Bromide<br /> One litre water</p> <p>Dilute 1 to 4 with water before use.</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p>For rehalogenation after fixing. Hans Bjelkhagen prefers this over the simpler GP 431 formulation for pulsed masters developed in Neofin Blau diluted 1:1.<br /> </p> <p> <u>Shelf life:</u>&nbsp;This stock solution lasts indefinitely, working solution about one week. </p> <p><u>Source:</u> <a href="NickAdvances.PDF" title="The Origins of the Dreaded PBQ" target="_new">N. J. Phillips, A. A. Ward, R. Cullen, D. Porter, "Advances in Holographic Bleaches," Photographic Science and Engineering 24, 120 (1980). </a></p> <p>Also: <a href="../Developers/AgfaBrochure.PDF" title="Second Edition of the brochure" target="_new">Agfa Gevaert Technical Information Bulletin 21.7271(480).</a></p> <p><a href="AgfaBrochure.PDF" title="More uselessness!" target="_self"></a></p> d48efd27d29b51b672f96b6ab7c17ff70898d403 0 1195 2503 2014-02-19T02:08:59Z Jsfisher 1 Created page with "== Bleach solution == <p>50 g&nbsp; Potassium Bromide<br /> 1.5 g&nbsp; Boric Acid<br /> 2 g&nbsp; p-Benzoquinone added just before use.<br /> One litre water</p> == Pro..." wikitext text/x-wiki == Bleach solution == <p>50 g&nbsp; Potassium Bromide<br /> 1.5 g&nbsp; Boric Acid<br /> 2 g&nbsp; p-Benzoquinone added just before use.<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p><u>Shelf life:</u>&nbsp; Not long with the PBQ added.</p> <p>This bleach never seemed to work for me.&nbsp; Don't even bother.</p> <p>Source:&nbsp; <a href="NickAdvances.PDF" title="The Origins of the Dreaded PBQ" target="_new">N. J. Phillips, A. A. Ward, R. Cullen, D. Porter, "Advances in Holographic Bleaches," Photographic Science and Engineering 24, 120 (1980). </a> </p> <p>Also<a href="../Developers/AgfaBrochure.PDF" title="A useless formula!" target="_new"> Agfa Gevaert Technical Information Bulletin 21.7271(480).</a></p> 428bbabac09c812dcf4dea76ace62764eccde8df 0 1196 2504 2014-02-19T02:10:00Z Jsfisher 1 Created page with "== Bleach solution == <p>30 g&nbsp; Potassium Iodide<br /> 3 g&nbsp; Boric Acid<br /> 2 g&nbsp; p-Benzoquinone added just before use.<br /> One litre water</p> == Proces..." wikitext text/x-wiki == Bleach solution == <p>30 g&nbsp; Potassium Iodide<br /> 3 g&nbsp; Boric Acid<br /> 2 g&nbsp; p-Benzoquinone added just before use.<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p><u>Shelf life:</u>&nbsp; Probably not too long after the PBQ is added.</p> <p>This bleach is supposed to upshift the replay color to longer wavelength, although I've never seen it work.&nbsp; Another one not to bother with in my book.</p> <p><u>Source: </u><a href="NickAdvances.PDF" title="The Origins of the Dreaded PBQ" target="_new">N. J. Phillips, A. A. Ward, R. Cullen, D. Porter, "Advances in Holographic Bleaches," Photographic Science and Engineering 24, 120 (1980). </a> </p> &nbsp;Also: <a href="../Developers/AgfaBrochure.PDF" title="More uselessness!" target="_self">Agfa Gevaert Technical Information Bulletin 21.7271(480)</a></p> e7904fbfee6ee2ba4b9ee32cf14a286a3bb8c091 0 1197 2505 2014-02-19T02:11:23Z Jsfisher 1 Created page with "== Bleach solution == <p>100 g Ferric Sodium-EDTA<br />10 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> A bleach that does not seem ..." wikitext text/x-wiki == Bleach solution == <p>100 g Ferric Sodium-EDTA<br />10 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> A bleach that does not seem to clear the plate at all. Don't even bother. It seems that they left out the necessary acid.</p> <p><u>Source:</u>&nbsp;Ilford Technical Information Publication 15717.GB. </p> <p><a href="AgfaBrochure.PDF" title="More uselessness!" target="_self"></a></p> dc75b1622438f404e3e90adc59105caf866592b9 0 1198 2509 2014-02-19T02:16:45Z Jsfisher 1 Created page with "== Bleach solution == <p>17 g Copper Sulfate<br /> 2 g Succinic Acid<br /> 55 g Potassium Bromide<br /> One litre water</p> = Processing == <p><u>Bleaching time:</u> One a..." wikitext text/x-wiki == Bleach solution == <p>17 g Copper Sulfate<br /> 2 g Succinic Acid<br /> 55 g Potassium Bromide<br /> One litre water</p> = Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<u>&nbsp;Agitation:</u>&nbsp; Intermittent</p> <p>A diluted version of Jeff Blyth's original Copper Sulfate Bleach. Succinic Acid is a dry powder to save on hazardous shipping charges of liquid acetic acid.<br /> </p> <p><u>Shelf life:</u>&nbsp;Pleasant blue-green color when mixed, dirty green when exhausted. Not prone to oxidation like PBQ.</p> <p><u>Source:</u>&nbsp;<a href="04-3020.pdf" target="_new">Photographers' Formulary JD-3 Holography Processing Kit Instructions</a></p> a65e85752d929d8915d06f3e30c9354b62b2036f 0 1199 2510 2014-02-19T02:18:01Z Jsfisher 1 Created page with "== Bleach solution == <p>35 g Copper Sulfate<br /> 5 g Sodium Bisulfate<br /> 100 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u..." wikitext text/x-wiki == Bleach solution == <p>35 g Copper Sulfate<br /> 5 g Sodium Bisulfate<br /> 100 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<u>&nbsp;Agitation:</u>&nbsp; Intermittent</p> <p>More or less the same as the original Jeff Blyth's original Copper Sulfate Bleach, again subbing a dry powder to save on hazardous shipping charges of liquid acetic acid.<br /> </p> <p><u>Shelf life:</u>&nbsp;Pleasant blue-green color when mixed, dirty green when exhausted. Not prone to oxidation like PBQ.</p> <p><u>Source:</u>&nbsp;<a href="04-3040.pdf" title="JARB" target="_new">Photographers' Formulary JD-4 (JARB) Holography Processing Kit Instructions</a></p> e97f757bbb25df1754bf1f2f6f242844d8a572d8 0 1200 2511 2014-02-19T02:19:03Z Jsfisher 1 Created page with "== Bleach solution == <p>35 g Copper Sulfate<br /> 10 ml Acetic Acid<br /> 110 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One..." wikitext text/x-wiki == Bleach solution == <p>35 g Copper Sulfate<br /> 10 ml Acetic Acid<br /> 110 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<u>&nbsp;Agitation:</u>&nbsp; Intermittent<br /> </p> <p>One of the best &quot;Cures for PBQ&quot;. Identical results to the PBQ, less costly than Fe EDTA. Unfortunately the original article did not disclose the strength of the Acetic Acid, whether it should be Glacial or 28%. It seems to work fine with the 28%.</p> <p><u>Shelf life:</u>&nbsp;Pleasant blue-green color when mixed, dirty green when exhausted. Not prone to oxidation like PBQ.</p> <p><u>Source:</u>&nbsp;Jeff Blythe, &quot;A Novel Approach to Colour Processing&quot;, <a href="JBCuSO4Wvfrnt.pdf" title="The first Copper Suphate Recipe I had ever seen" target="_new">Wavefront Volume 2 Number 3, p.23 (1987)</a></p> c8adcb8a9daf3c80886dc7f0c2c0550c66200f77 0 1201 2512 2014-02-19T02:20:27Z Jsfisher 1 Created page with "== Bleach solution == <p>9.5 g Potassium Dichromate<br /> 8 mL Sulfuric Acid (or 24 g Sodium Bisulfate)<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u..." wikitext text/x-wiki == Bleach solution == <p>9.5 g Potassium Dichromate<br /> 8 mL Sulfuric Acid (or 24 g Sodium Bisulfate)<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> Time it takes to clear plus 15 seconds, not to exceed 2 minutes.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Constant</p> <p>Distilled water is recommended otherwise white scum may collect in the emulsion. First hologram in the bath may take a long time to clear. When clearing time exceeds two minutes the bath is becoming saturated with silver salts and needs to be replaced. Hanging the plate vertically in a tank or with emulsion side down in a tray during bleaching speeds the exit of the soluble silver salts from the emulsion.</p> <p>This was Kodak's bleach for reversal processing of direct positive black and white transparency or movie films.</p> <p> <u>Shelf life:</u>&nbsp;This solution stores indefinitely, should be dumped when it takes longer than a couple of minutes to clear. </p> <p><u>Source:</u>&nbsp;<a href="ReversalBleaching.PDF" title="Predates Pyrochrome" target="_new">R. L. Lamberts and C. N. Kurtz, "Reversal Bleaching for Low Flare Light In Holograms", Applied Optics 10, 1342 (1971</a>)</p> ab3322d644d8215e2ee001ae1c92d1a0dcafe6e6 0 1202 2513 2014-02-19T02:21:35Z Jsfisher 1 Created page with "== Bleach solution == <p><strong>Part A:</strong><br /> 2.5 g Potassium Permanganate<br /> 8 mL Sulfuric Acid or 24 g Sodium Bisulfate<br /> One litre water</p> <p><stron..." wikitext text/x-wiki == Bleach solution == <p><strong>Part A:</strong><br /> 2.5 g Potassium Permanganate<br /> 8 mL Sulfuric Acid or 24 g Sodium Bisulfate<br /> One litre water</p> <p><strong>Part B:</strong><br /> 10 g Sodium Bisulfite<br /> One litre water</p> == Processing == <p>Don't mix the two together. Immerse the plate for one minute in Part A, then one minute in Part B, followed by a five to ten minute wash. The sodium bisulfite gives off quite a strong effluvia, respirators mandatory. It will remove the pyrogallol or pyrocatechol stain from holograms, or most any stain in the holographic darkroom's trays.</p> <p>These baths can also be used as a reversal bleach, but they are temperamental.</p> <p><u>Bleaching time:</u> One and a half times the time it takes to clear if used as a reversal bleach.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p> <u>Shelf life:</u>&nbsp;This stock solution lasts practically indefinitely.</p> <p><u>Source:</u><a href="ReversalBleaching.PDF" title="Predates Pyrochrome" target="_new">R. L. Lamberts and C. N. Kurtz, "Reversal Bleaching for Low Flare Light In Holograms", Applied Optics 10, 1342 (1971)</a></p> 9afe125a2007dde0c67ddba4eaecc8dd3519817d 0 1203 2514 2014-02-19T02:22:29Z Jsfisher 1 Created page with "== Bleach solution == <p> 20 g Mercuric Chloride<br /> 20 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times t..." wikitext text/x-wiki == Bleach solution == <p> 20 g Mercuric Chloride<br /> 20 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p>Although some people swear by it in a develop-wash-fix-wash-bleach in mercuric chloride-wash-refix-wash-rebleach in the ferricyanide 30-wash-photo-flo regime, it offers no improvement over anything else listed in this formulary. It is poisonous, and permanence of the holograms is questionable</p> <p> <u>Shelf life:</u>&nbsp;This stock solution lasts practically indefinitely.</p> <p><u>Source:</u> Integraf Handout, circa late 1970's.</p> 91e20a0e7628c6b8e8f1dcbad80d2a5fc9db19f8 0 1204 2515 2014-02-19T02:24:18Z Jsfisher 1 Created page with "== Bleach solution == <p>12 g Ferric Sulfate<br /> 12 g di-Sodium EDTA<br /> 30 g Potassium Bromide<br /> 50 g Sodium Bisulfate)<br /> One litre water</p> == Proces..." wikitext text/x-wiki == Bleach solution == <p>12 g Ferric Sulfate<br /> 12 g di-Sodium EDTA<br /> 30 g Potassium Bromide<br /> 50 g Sodium Bisulfate)<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> To clear plus one minute. (Usually in excess of six minutes!)</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<u>&nbsp;Agitation:</u>&nbsp; None<br /> </p> <p>A slow, diluted Fe EDTA bleach which eliminates non-uniform scattering patches throughout the emulsion. The key to success is to avoid the urge to agitate, as this one can take up to fifteen minutes to clear a well-exposed plate.</p> <p><u>Shelf life:</u>&nbsp;Leaving the solution exposed to air (uncovered tray) will extend the lifetime of the oxidizer. It has run its useful course when it takes very long to completely clear, like over 5 minutes.</p> <p><u>Source:</u>&nbsp;Nicholas Phillips, &quot;New Recommendations for the Processing of Ilford Plates&quot;, handout at Lake Forest College Holography Workshop II, July 1989.</p> e4c3e422a76e92d01f5959dd9d0a5d96ce9ffd7e 0 1205 2516 2014-02-19T02:25:17Z Jsfisher 1 Created page with "== Bleach solution == <p>30 g&nbsp; Potassium Iodide<br /> 15 g&nbsp; Borax<br /> 2 g&nbsp; Potassium Dichromate<br /> 2 g p-Benzoquinone added just before use.<br /> ..." wikitext text/x-wiki == Bleach solution == <p>30 g&nbsp; Potassium Iodide<br /> 15 g&nbsp; Borax<br /> 2 g&nbsp; Potassium Dichromate<br /> 2 g p-Benzoquinone added just before use.<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p><u>Shelf life:</u>&nbsp; Probably not too long after the PBQ is added.</p> <p><u>Source:</u>&nbsp;<a href="NickAdvances.PDF" title="The Origins of the Dreaded PBQ" target="_new">N. J. Phillips, A. A. Ward, R. Cullen, D. Porter, "Advances in Holographic Bleaches," Photographic Science and Engineering 24, 120 (1980). </a></p> 7876384e0171fb043e519667b2538521367a7523 0 1206 2517 2014-02-19T02:26:10Z Jsfisher 1 Created page with "== Bleach solution == <p> 30 g Potassium Ferricyanide<br /> 30 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half ti..." wikitext text/x-wiki == Bleach solution == <p> 30 g Potassium Ferricyanide<br /> 30 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p>For rehalogenation after fixing. The first transmission bleach I was introduced to, however it's best not to bother with because it prints out almost immediately.<br /> </p> <p> <u>Shelf life:</u>&nbsp;This stock solution lasts practically indefinitely.</p> <p><u>Source:</u> Integraf Handout, circa late 1970's.</p> af08cb1e692f1ee3d9cb1331f5cd4893e0a9f97d 0 1207 2518 2014-02-19T02:27:16Z Jsfisher 1 Created page with "== Bleach solution == <p>2 g Potassium Dichromate<br />2 mL Sulfuric Acid (or 6 g Sodium Bisulfate)<br /> 30 g Potassium Bromide<br /> One litre water</p> == Processing =..." wikitext text/x-wiki == Bleach solution == <p>2 g Potassium Dichromate<br />2 mL Sulfuric Acid (or 6 g Sodium Bisulfate)<br /> 30 g Potassium Bromide<br /> One litre water</p> == Processing == <p><u>Bleaching time:</u> One and a half times the time it takes to clear.</p> <p><u>Temperature:</u>&nbsp; 20C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <u>Agitation:</u>&nbsp; Intermittent</p> <p>The first bleach that I saw that worked with the Agfa HD series of emulsions when they came out, in conjunction with Kodak D-8 as the developer. It is a bit noisier than current formulations, but just as bright. It is a variation of the Kodak R-10 formula.</p> <p><u>Source:</u>&nbsp;<a href="TJBleach.PDF" title="Wish it were dated!" target="_new">Integraf Handout, circa 1982?</a></p> 050bb09e4099912a9c5c729018013a95ea628a47 0 1024 2523 2522 2014-02-19T02:50:31Z Jsfisher 1 wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] </div> ==== Stain Remover ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] eccdaa067ad3cd6371837e2ce56f440e9746a2a1 2524 2523 2014-02-19T02:51:09Z Jsfisher 1 /* Ascorbic acid */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] </div> ==== Stain Remover ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 741b4e803e71ee905c426ca8886b9ed350120111 2525 2524 2014-02-19T02:52:34Z Jsfisher 1 /* Developers */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] </div> ==== Stain Remover ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] f4937a332bc7685c5628c5c4daa709935768b422 2526 2525 2014-02-19T02:59:54Z Jsfisher 1 Undo revision 2525 by [[Special:Contributions/Jsfisher|Jsfisher]] ([[User talk:Jsfisher|talk]]) wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] </div> ==== Stain Remover ==== <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 741b4e803e71ee905c426ca8886b9ed350120111 2527 2526 2014-02-19T03:02:09Z Jsfisher 1 Undo revision 2523 by [[Special:Contributions/Jsfisher|Jsfisher]] ([[User talk:Jsfisher|talk]]) wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] </div> ==== Stain Remover ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] 9a42987de4eea3b5b40bfb5304f83211b8b7417a 2528 2527 2014-02-19T03:02:32Z Jsfisher 1 /* Alphabetical listing */ wikitext text/x-wiki == Developers == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> === Developing agent listing === ===== Ascorbic acid ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Catechol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Chlorohydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] </div> ===== Hydroquinone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] </div> ===== Metol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Phenidone ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Pyrogallol ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> === Developer type === ===== Colloidal ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / GP-2 | GP-2]] </div> ===== General Holographic ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | BBAA]] * [[Ewesly / Holographic Formulae / GP 61 | GP 61]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | JD-4]] * [[Ewesly / Holographic Formulae / Kodak D-8 | Kodak D-8]] * [[Ewesly / Holographic Formulae / Kodak D-11 | Kodak D-11]] * [[Ewesly / Holographic Formulae / Kodak D-19 | Kodak D-19]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | LN-7]] * [[Ewesly / Holographic Formulae / Nick's No. 5 | Nick's #5]] * [[Ewesly / Holographic Formulae / LN-7, Nick's No. 7 | Nick's #7]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / BBAA, JD-4, TJ-1 | TJ-1]] </div> ===== Photographic Film ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-76 | Kodak D-76]] </div> ===== Photographic Paper ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak D-72 | Kodak D-72]] </div> ===== Pulsed (Extremely Short Exposures) ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / SM-6 | SM-6]] </div> ===== Tanning ===== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | CWC2]] * [[Ewesly / Holographic Formulae / GP 62 | GP 62]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | JD-1]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-2]] * [[Ewesly / Holographic Formulae / CWC2, JD-2, JD-3 | JD-3]] * [[Ewesly / Holographic Formulae / Nick's No. 6 | Nick's #6]] * [[Ewesly / Holographic Formulae / JD-1, Pyrochrome | Pyrochrome]] </div> == Bleaches == === Alphabetical listing === <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> === Oxidizer listing === ==== Copper Sulfate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] </div> ==== Ferric EDTA ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] </div> ==== Ferric Nitrate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] </div> ==== Mercuric Chloride ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] </div> ==== PBQ (para-benzoquinone) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] </div> ==== Potassium Dichromate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Potassium Ferricyanide ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] </div> ==== Potassium Permanganate ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> === Type listing === ==== Rehalogenating ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Benign Ferric EDTA | Benign Ferric EDTA]] * [[Ewesly / Holographic Formulae / CWPBQ2 | CWPBQ2]] * [[Ewesly / Holographic Formulae / Ferric Nitrate | Ferric Nitrate]] * [[Ewesly / Holographic Formulae / GP 431 | GP 431]] * [[Ewesly / Holographic Formulae / GP 432 | GP 432]] * [[Ewesly / Holographic Formulae / GP 433 | GP 433]] * [[Ewesly / Holographic Formulae / Ilford EDTA | Ilford EDTA]] * [[Ewesly / Holographic Formulae / JD-3 Kit | JD-3 Kit]] * [[Ewesly / Holographic Formulae / JD-4 Kit | JD-4 Kit]] * [[Ewesly / Holographic Formulae / Jeff Blyth's Copper Sulphate | Jeff Blyth's Copper Sulphate]] * [[Ewesly / Holographic Formulae / Kodak R-10 | Kodak R-10]] * [[Ewesly / Holographic Formulae / Mercuric Chloride | Mercuric Chloride]] * [[Ewesly / Holographic Formulae / No Patchy Haze | No Patchy Haze]] * [[Ewesly / Holographic Formulae / PBQ #3 | PBQ #3]] * [[Ewesly / Holographic Formulae / Potassium Ferricyanide | Potassium Ferricyanide]] * [[Ewesly / Holographic Formulae / TJ | TJ]] </div> ==== Reversal (Silver Solvent) ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Pyrochrome | Chrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Dichromate]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-1 Kit]] * [[Ewesly / Holographic Formulae / Pyrochrome | JD-2 Kit]] * [[Ewesly / Holographic Formulae / Kodak R-9 | Kodak R-9]] * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] * [[Ewesly / Holographic Formulae / Pyrochrome | Pyrochrome]] * [[Ewesly / Holographic Formulae / Pyrochrome | Reversal]] </div> ==== Stain Remover ==== <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> * [[Ewesly / Holographic Formulae / Kodak S-13 | Kodak S-13]] </div> == Fixers == (one of these years) == Colorful chemical Techniques == * [[Ewesly / Holographic Formulae / Triethanolamining | Triethanolamining]] a8ff35839edb9af9e40205cd4fdd7e12757012ea 0 952 2529 2486 2014-02-23T22:56:38Z Jsfisher 1 wikitext text/x-wiki The following pages were derived from Ed Wesly's web pages at http://nlutie.com/ewesly. = Hologrammy = {| |- | * [[Ewesly / Holographic Pedagogy | Holographic Pedagogy]] * [[Ewesly / Holographic R&D | Holographic R&D]] * [[Ewesly / Holographic Artwork | Holographic Artwork]] * [[Ewesly / Holographic Formulae | Holographic Formulae]] * [[Ewesly / Publications | Publications]] * [[Ewesly / Holographic Consumer Reports | Holographic Consumer Reports]] | [[Image:WinterWonderlandCsm.jpg|right]] |} f13068511f9d02232302699a06aa606531ef2a5e 6 1208 2530 2014-03-20T18:35:47Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1209 2531 2014-03-20T18:35:48Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1210 2532 2014-03-20T18:35:49Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1211 2533 2014-03-20T18:35:49Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1212 2534 2014-03-20T18:35:50Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1213 2535 2014-03-20T18:35:50Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1214 2536 2014-03-20T18:35:51Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1215 2537 2014-03-20T18:35:51Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1216 2538 2014-03-20T18:35:52Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 1217 2539 2014-03-20T18:43:51Z Jsfisher 1 Created page with "''by Ed Wesly'' <p>There has been some lively discussion as to how to process the great new holographic recording material from Russia, the Sphere-S brand of plates distribut..." wikitext text/x-wiki ''by Ed Wesly'' <p>There has been some lively discussion as to how to process the great new holographic recording material from Russia, the Sphere-S brand of plates distributed by Geola of Lithuania, affectionately called GEO-3. It is an ultra-fine grained panchromatic emulsion, similar to the Slavich PFG series of -03C and -03M.</p> <p>I had told Hans that I did not succeed with that emulsion until I followed TJ&rsquo;s (Dr. Tung Jeong) processing scheme which starts with a 30&rdquo; immersion in cold running water, like only the cold side of the faucet turned on, which in Chicago is about 50F (10C). (Sorry my metric colleagues, I myself am metrified, but my trusty Weston Dial Thermometer which I have used since the &lsquo;70&rsquo;s is calibrated in Fahrenheit only.) Then 30&rdquo; only in the JD-4 developer, more cold water for 2-3&rsquo;, bleach until clear in a Kodak R-10 derivative that I call TJ bleach since I first saw it on an Integraf mimeographed handout when 8E75HD first came out. (2 g Potassium Dichromate, 2 mL Sulfuric Acid, 30 g Potassium Bromide) Another cold water wash 3 – 5&rsquo;, Photo-Flo and air dry.</p> <p>I told Hans that this really works, and although not skeptical, like a good holographer he wanted to see it for himself. So on his latest excursion from the UK to the US, we tried it.</p> <p>Set up the classic waffle iron standard object, used 532 nm from my cherry Compass 315M, got 180 microWatts per square centimeter (μW/cm2) flux, and exposed some 62 mm square plates for 3000, 4200, 6000, 8400 and 12,000 microJoules per square centimeter (μJ/cm2) exposure doses. (This was a series of exposures where they were differed by half-stops.) Processed exactly as described above. Results below.</p> [[image:Cold5Up.jpg|750px]] <p>They were all great, but it seemed that the 6000 μJ/cm2 was the best for brightness and signal to noise when looking at the holograms in person. The 8400 μJ/cm2 appears a bit brighter in the photo, probably due to some extra developed noise. The 12,000 μJ/cm2 seems dimmer because it’s on the downhill side of the curve. Hans was nicely surprised! Especially when it was proven that there was no emulsion shrinkage as the plate was replaced on the object and illuminated with laser light and got a nice shadow on the object from the plate stealing the beam from the object and turning it in to a reconstructed wavefront, plus it was nano-positioned manually until we got real-time fringes! This was the first time that I had shot this material in the green, having proven to myself that the cold water processing worked well with the material using He-Ne red previously, and I was amazed again, since the shorter wavelength recordings are more difficult. (One of these days I will get some blue photons!)</p> <p> Then we tried the processing scheme that he was most comfortable with, the traditional CWC2 developer but with a hardening step before it. Shot 3000, 6000, and 12,000 μJ/cm2 exposure doses, and pre-hardened with formaldehyde, (per the Slavich instructions, 10 mL of 37% Formalin solution, 2 g potassium bromide, 5 g sodium carbonate), a quick rinse to remove the formaldehyde, and then into the catechol and ascorbic acid stew at room temperature, 70F (21C), same bleach as above, and air dried. One other plate had been exposed at 6000 μJ/cm2, and slipped in along with its brethren in the developer but without having been pre-hardened.</p> <p>While they were pre-hardening for 6 minutes I was complaining that this was such a nasty step, the typical bargain basement holographer like myself doesn’t want to have formaldehyde around, how do you get it unless you are an undertaker (and I do have an undertaker friend who was a former holography student, so that’s how I have it), and so on about this stuff. So why would first Slavich and now Sphere-S want to have to include this nasty step in their scheme?</p> <p>Hans took credit along with Dalibor Vukicevic in implementing the formaldehyde pre-hardening step for this class of materials, the PFG-03M, -03C and now GEO-3. There is a very real need for this nasty step because the gelatin needs to be softer than typical photographic products to let the silver halide crystals precipitate to the ultra-fine grains in these emulsions. They had tried various other pre-hardening formulations, without the embalming fluid, but they did not work as well as this stuff.</p> <p>This trio held their own brightness-wise with the first set of 5, however they were noisier. Here are the 3 pre-hardened CWC2 holograms. Anyone would certainly be happy with these!</p> [[image:CWC23Up.jpg|750px]] <p>Checking out the same exposure doses but different processing side by side, the CWC2 replays noisier. </p> [[File:SideBySide.jpg|750px]] <p>Because of the longer development time film grain noise could come up spontaneously, so this picture below compares the CWC2 3000 μJ/cm2 exposure dose to the cold JD-4 6000 μJ/cm2 and the CWC2 is still noisier. Inspect the shadows and the dark areas in the ball bearings that hold up the plate. Possible further exploration would be to try the CWC2 developer either cold, and/or shorter immersion times.</p> [[File:CUPrevsCold.jpg|750px]] <p>But what was proven conclusively is that this material really does need the hardening step! The holo on the left was not pre-hardened, but processed in the same batch as the others that had received pre-hardening. There is a shift to shorter wavelengths, the shift is random, and it seems like the gelatin distortion made the image less sharp! (Both 6000 microjoules per square centimeter exposure.)</p> [[File:PrevsNot.jpg|750px]] <p>Another plate was exposed at the 3000 μJ/cm2 exposure dose and soaked in cold water before the CWC2 room temperature baths, and although it didn’t shrink as badly as the untreated plate, it still had some unacceptable flaws. </p> [[File:CldvsPre.jpg|750px]] <p>Perhaps a longer soak in the cold could have helped, and/or the process continued at the same lower temperature like the first set.</p> <p>Conclusions: The Sphere-S GEO-3 is my emulsion of choice, in spite of its low sensitivity. Its soft gelatin, necessary for precipitating the ultra-fine grains, needs something to harden it so that it doesn’t distort under the duress of development.</p> <p>The formaldehyde hardening step introduced by Hans and Dalibor really is necessary. But TJ came up with a much more palatable solution, possibly inspired by the fact that gelatin desserts need to be refrigerated to become solid, with the cold water pre-hardening step toughening up the protein strands so that the coating thickness doesn’t change between the exposure and replay steps.</p> <p>Another advantage of the cold process with its developer temperature of 65F along with the short immersion is that the random development of grains that contribute to noise is suppressed, making the shadow areas nice and dark, for higher contrast and signal to noise ratio. Look at the same shadow areas in the JD-4 developed and CWC2 areas; the ball bearings should have no haze in their images. </p> <p>These short developing times and the low processing temperature run counter-intuitive to previous photographic printing experience. If a photographic print is developed in too cold of a solution, the blacks in the shadows never reach a decent density. Short times of immersion would not allow the density to build up properly, either.</p> <p>But this type of silver halide material is an altogether different beast, and it looks like I have finally found a way to process it to get the best results!</p> <p>Embarrassing Postscript: Looking at the photos on the monitor at bigger than life exposes some blemishes like the blue spots at the edges caused by my sweaty paws during handling, plus my inconsistent cutting of a large plate into the 63 mm chunks. Cleanliness is next to godliness in the image-making world! Hopefully the reader will be more careful than myself when making their final display hologram on what appears to be the silver halide holographic record material we have been waiting for!</p> 600b7c5a544ba30fabfc68693086ef3c7166c6c3 0 1 2540 2521 2014-03-20T18:45:10Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] d28d7fc11c30f1b14e3f26a2ef2a349036d5bfa3 2543 2540 2014-03-27T19:52:57Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note|The hologforum.org site may be unreachable from some Internet locations. There appears to be a routing issue in Austria. 27 March 2014|error}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 36f67e934b2f441e83db71f466501f28c1f05a3b 2544 2543 2014-03-27T19:53:56Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note|The hologforum.org site may be unreachable from some Internet locations. There appears to be a routing issue in Austria.<br>27 March 2014|error}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 95cf26c345a641236c40d4f8212d751968be533c 2545 2544 2014-03-27T19:54:28Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note|27 March 2014: The hologforum.org site may be unreachable from some Internet locations. There appears to be a routing issue in Austria.|error}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 60249601f8e1b9f22238d673ccc55b7e62934cdf 2546 2545 2014-03-28T18:33:02Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note|27 March 2014: The holoforum.org site may be unreachable from some Internet locations. <br>28 March 2014: '''Update:''' Although holoforum.org may still be unreachable, http://a2.no-ip.org/forum is working.}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 3e0eea703684ed9bcbac931bce5d05cc0765ed41 2547 2546 2014-03-28T18:34:06Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note|27 March 2014: The holoforum.org site may be unreachable from some Internet locations. <br>28 March 2014: '''Update:''' Although holoforum.org may still be unreachable, http://a2.no-ip.org/forum is working.|reminder}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 1c4e0002edd8d24e22f75c6ef5e90e465bc70679 2548 2547 2014-03-30T00:21:15Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note|27 March 2014: The holoforum.org site may be unreachable from some Internet locations. <br>28 March 2014: Update: Although holoforum.org may still be unreachable, http://a2.no-ip.org/forum is working. <br>29 March 2014: '''Update:''' Issues with holoforum.org have been resolved.|reminder}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 84c4f4e855433d9c7a1cd73b14bf254081ac7b2e 2549 2548 2014-03-30T00:22:45Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note|27 March 2014: The holoforum.org site may be unreachable from some Internet locations.<br>28 March 2014: Update: Although holoforum.org may still be unreachable, http://a2.no-ip.org/forum is working.<br>29 March 2014: '''Update: Issues with holoforum.org have been resolved.'''}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] b802d7a989ce62f08baccc172e64edac037f2801 2556 2549 2014-04-08T02:24:43Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note|27 March 2014: The holoforum.org site may be unreachable from some Internet locations.<br>28 March 2014: Update: Although holoforum.org may still be unreachable, http://a2.no-ip.org/forum is working.<br>29 March 2014: '''Update: Issues with holoforum.org have been resolved.'''}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * '''[[Experimenter's Corner#Albumen Emulsions Plates | plates]]''' * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 311b2018d9ec2b372706031d620afb14c7b1f147 2557 2556 2014-04-08T02:26:24Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{Note|27 March 2014: The holoforum.org site may be unreachable from some Internet locations.<br>28 March 2014: Update: Although holoforum.org may still be unreachable, http://a2.no-ip.org/forum is working.<br>29 March 2014: '''Update: Issues with holoforum.org have been resolved.'''}} [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 7f62505b0e34748f594530827fd8b5520084f7cb 2561 2557 2014-04-09T18:54:40Z Jsfisher 1 wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 1b6a63d9504cca16af3693c84c4f0234ce96575b 2564 2561 2014-04-20T19:22:20Z Jsfisher 1 wikitext text/x-wiki <seo description="Master resource for all things holographic."></seo> '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] e51abb08b30955d786685f67db60bf5ac8a5033a 2565 2564 2014-04-20T19:24:08Z Jsfisher 1 Undo revision 2564 by [[Special:Contributions/Jsfisher|Jsfisher]] ([[User talk:Jsfisher|talk]]) wikitext text/x-wiki '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 1b6a63d9504cca16af3693c84c4f0234ce96575b 2566 2565 2014-04-20T19:27:20Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 042044bb0bda9f5e8261df73064018d53b54fa57 0 501 2541 1809 2014-03-20T20:07:29Z Jsfisher 1 wikitext text/x-wiki Silver Halide is one of the most popular recording materials. The historical and available commercially available films properties are listed here: *[[Silver Halide Film]] *[[DIY Silver Halide Film]] *[[Silver Halide Processing Chemistry]] *Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''' with comments *[[Silver Halide Film vs Chemistry vs Hologram Type]] *[[Cold Water Processing]] *[[Silver Halide Sensitized Gelatin]] SHSG *[[Index Matching]] *[[Pre-Swelling]] *[[Post-Swelling]] *[[Squeegee Technique]] *[[Fringe Photos]] *[[Painting Holograms]] *[[Exposure Tests]] *[[Hardening Holograms to Fix the Color]] *[[Psuedocolor Processing]] *[[Laminating Film to Glass]] b034319c1d16e14a4d9750757a132a3689effb2b 0 274 2542 1711 2014-03-25T17:44:41Z Jsfisher 1 /* Film and Chemistry */ wikitext text/x-wiki Please add any links you have found useful. Try to alphabatize by Site title. '''[[Books]]''' can be found [[Books|here]]. ===Links to Holography Instruction=== *[http://home.comcast.net/~gakall/holopg/ Amateur Holography] Simple & Low Budget *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.nobel.se/physics/laureates/1971/gabor-lecture.pdf Dennis Gabor's Nobel Lecture, December 11, 1971] *[http://www.holographer.org The Holographer] *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] *[http://amasci.com/amateur/hand1.html Hand Drawn Holograms] *[http://www.holoworld.com/holoportraits/index.html Hand Made Hologram Portraits] An Amateur/Hobbyist Guide *[http://www.holostudios.com/holohelper/index.html Hologram Basic Principles] by Jason Sapan *[http://www.holokits.com/newsarticles.htm Integraf's Articles] *[http://www.focalimage.com/public/kaveh-PhD.pdf Kaveh's Thesis] *[http://www.buildcoolstuff.com/gallery/holograms.html Laser Pointer Holograms] *[http://www.repairfaq.org/sam/lasersam.htm Laser Sam's FAQ] The best source of laser related information on the net. *[http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html MIT Spring 2002 Holography course] *[http://www.holo.com/holo/book/book.html Practical Holography] by Christopher Outwater & Van Hamersveld *[http://www.holography.ru/techeng.htm Russion Holography 25 Holography Lessons] *[http://www.dragonseye.com/blog/categories/2-Tutorials Holography Tutorials] by Michael Harrison *[http://www.physics.ohio-state.edu/~kagan/holography/index.html Holography course at Ohio State] *[http://teched.vt.edu/gcc/CurriculumMaterials/HoloProject/HTML/index.html Virtual Holography course at Virginia Tech] *[http://www.ph.ed.ac.uk/~wjh/teaching/mo/holography.html University of Edinburgh] *[http://www.3dimagery.com Nuts to bolts online descriptions for hobbyist] *[http://geola.lt/download/synfography_virtual_scene_setup.pdf Synfography basics - virtual scene setup for Geola's colour holographic printing] ===Links to Holography Supplies and Tools=== ====Turnkey Equipment==== *[http://www.myholostudio.com/ Analogue holography] {Complete holography studios} *[http://geola.lt/show.php?lang=eng&cont=holo_index&lside=holo_index_left Digital holographic printing - Synfography] {Complete digital solutions} ====Electronics==== *[http://www.digikey.com DigiKey] {Electronics} *[http://www.goldmine-elec.com Gold Mine Electronics] *[http://www.allelectronics.com/ All Electronics] {Electronics} *[http://www.alltronics.com Alltronics] {Electronics} *[http://www.oatleyelectronics.com/ Oatley Electronics] {Electronics} *[http://www.mouser.com/Mouser Mouser] {Electronics} ====Film and Chemistry==== *[http://www.integraf.com Integraf] Film, Kits and Books *[http://www.laserreflections.com Laser Reflections] Film *[http://www.slavich.com Slavich] Film, Plates and Chemistry *[http://www.geola.lt/eshop/index.htm Geola] Certified Slavich film and plates made for Geola distribution network, Chemistry *[http://www.ilfordphoto.com/holofx/holofx.asp Ilford] Harman HoloFX fine-grain red and green sensitive plates *[http://www.adorama.com Adorama] Supplier of Harman HoloFX plates *[http://www.forthdimension.net Forth Dimension] Film and Supplies *[http://www.photoformulary.com Photographer's Formulary] Chemistry *[http://www.sigmaaldrich.com/ Sigma Aldrich] Chemicals *[http://perso.wanadoo.fr/holographie/GB/index.html Ultimate Film] Film *[http://www.abra-electronics.com Abra Electronics] Isopropyl Alcohol *[http://www.colourholographic.com Colour Holographics] BB Plates - Red, Green, Blue, Pan *[http://www.filmotec.de/Produkte/produkte.html Filmotec] ORWO - Red, Green, Pan in works *[http://www.fujihunt.com/fuji/fhweb2004.nsf/pagesbykey/Holo%20products?OpenDocument Fuji] Pan said to be discontinued ====Kits==== *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.geola.lt/show.php?lang=eng&cont=phot_en_kit&lside=phot_index_left Geola] {Holography supply refill kit} ====Lasers, Parts and Supplies==== *[http://www.optima-optics.com Optima] {Laser Diode Parts} *[http://www.nvginc.com NVG Inc.] {Laser Diode Parts} *[http://www.mi-lasers.com/index1.html Meredith Instruments] {Used Gas Lasers} *[http://www.roithner-laser.com/ Roithner] {Lasers and diodes} *[http://www.cnilaser.com/ CNI Laser] {DPSS Lasers}] *[http://www.lasersurplus.com/ Laser Surplus Sales] {Used Lasers} *[http://www.innolas.co.uk/ Innovative Laser Technology] {Lasers and parts} *[http://www.geola.com/ Geola] {High energy pulsed lasers, Holographic studios} ====Optics and Table Supplies==== *[http://www.thorlabs.com Thor Labs] {Optics} *[http://www.edmundoptics.com/us/onlinecatalog/browse.cfm Edmund Optics] {Optics} *[http://www.imagesco.com ImagesCo] {Supplies and inexpensive optics} *[http://www.surplusshed.com Surplus Shed] {Surplus Optics} *[http://www.murni.com/kit_0.htm Coulter Telescopes] {Inexpensive Collimating Mirrors} *[http://www.abrisa.com/index.asp Abrisa] {Glass Products, Dichroic Mirrors} *[http://www.lenoxlaser.com/ Lenox Laser] {Piinholes} *[http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=5646 Harbor Freight] {Magnetic Bases} *[http://www.use-enco.com/CGI/INSRIT?PMAKA=625-0300&PMPXNO=946102&PARTPG=INLMK3 ENCO] {Magnetic Bases} *[http://www.geola.com/ Geola] {Optics for pulsed holography} ====Robotics==== *[http://www.solarbotics.com SolarBotics] {Robot Technology} ====Surplus and Other Stuff==== *[http://www.sciplus.com American Science Surplus] {Surplus Parts and Cool Stuff} *[http://www.spsenergy.com/index.htm SPS Energy] {Solar Cells as Light Meter Probes} *[http://www.fgsi.com/oracal.htm Oracal] {instead of black paint for reflection holos #651} ====Tooling and Machining==== *[http://www.reidtool.com Reid Tool] {Tooling supplies} *[http://www.mscindustrial.com MSC Industrial] {Raw Metal and Machining Supplies} *[http://www.mcmaster.com McMaster Carr] {Raw Metal and Machining Supplies} ====Tools==== *[http://www.use-enco.com Enco] {Tools} ====Technical==== *[http://www.moshier.net/rtd-readme.html Thermistor calibration] ===Links to Amateur/Individual Holographers=== *[http://www.techsoft.no/holography/ronny_anderassen.htm Ronnie Anderassen] *[http://www.anait.com/ Anait] *[http://members.shaw.ca/holopix/My_holograms.html TomB] *[http://www.holography.demon.co.uk/ Margaret Benyon] *[http://rudieberkhout.home.mindspring.com/ Rudie Berkhout] *[http://cabd0.tripod.com/holograms/ Jeff Blyth] *[http://universal-hologram.com/index.htm Greg Cherry] *[http://web.mit.edu/museum/lightforest/lightforest.html Betsy Connors] *[http://www.holoworld.com/ Frank Defreitas] *[http://www.jfairstein.com/holoindex.html Jon Fairstein] *[http://www.hologramm.ch.vu/ Floh] *[http://webhome.idirect.com/~hgdesign Howard Gerry] *[http://www.ghisays.net Andres Ghisays] *[http://universal-hologram.com/nini%20gorglione.htm Nancy Gorglione] *[http://www.dragonseye.com/blog Michael Harrison] *[http://www.techsoft.no/holography Vidar Hegdal] *[http://www.pearljohn.co.uk/ Pearl John] [http://pearljohn.blogspot.com/ her Blog] *[http://www.bobdbob.com/~protius Tommy Johnson] *[http://www.designerinlight.com Colin Kaminski] *[http://www.holocenter.or.kr/ Juyong Lee] *[http://www.lucente.biz/index.html Mark Lucente] *[http://www.indimensionn.com/page3.html Bill McGarvin] *[http://www.holography.nl/ Kris Meerlo] *[http://www.rotorwave.com/holography.htm Ron Michael] *[http://www.3dimagery.com Steve Michael] *[http://holographics.com.au/ Martina Mrongovius] *[http://www.lasart.com/ August Muth] *[http://www.hololab.com/ Ikuo Nakamura] *[http://www.anamarianicholson.com/ Ana Maria Nicholson] *[http://www.holograms3d.com/ John Pecora] *[http://www.apepper.com/ Andrew Pepper] *[http://www.alchemists.com/visual_alchemy/holography.html Al Razutis] *[http://www.vilamedia.com/gallery.html Doris Vila] *[http://wengam.com/ Wenyon & Gamble] *[http://perso.wanadoo.fr/redlum.xohp/argonlaser.html W's Laser Projects Page] *[http://www.martymouse.net/happyfeet/ Danny Bruza (Danny Bee)] ===Links to Holograms For Sale=== *[http://www.holography.ru/maineng.htm Beautiful Russian Holograms] *[http://www.holograms.bc.ca Royal Holographic Art Gallery] *[http://holographiccenter.com/ Holographic Center] *[http://www.triple-take.com Triple-Take] *[http://www.hologramstore.biz Dragon's Eye Creations] *[http://www.holoshop.nl HoloShop.nl] *[http://www.holoshop.com Holograms & Lasers Intl] *[http://www.geola.lt/show.php?lang=eng&cont=holoindex&lside=holo_index_left Geola - Digital holographic prints - Synfograms - Colour and movement in one] *[http://universal-hologram.com/ Hologram Art] *[http://www.rabbitholes.com/art-gallery/ Holographic Art Prints from Computer 3D and Animation from Leading 3D Artists] *[http://www.rabbitholes.com/order-samples/ Samples kits of Rabbitholes Holograms] ===Links to Professional Holographers=== *[http://www.3dimagery.com Three Dimensional Imagery] Hologram Production Lab *[http://universal-hologram.com/index.htm Cherry Optical] Hologram Production Lab *[http://www.forthdimension.net Forth Dimension] Hologram Production Lab *[http://www.holonorth.com/main.html Holographics North] Hologram Production Lab *[http://www.holographsonmain.com Holographs on Main] Portrait Studio *[http://www.laserreflections.com Laser Reflections] Pulsed Holography Lab *[http://www.zebraimaging.com Zebra Imaging] Hologram Production Lab *[http://www.geola.lt Geola] Synfograms (Geola's digital holograms) - life scene colour imaging with animation *[http://www.rabbitholes.com RabbitHoles Media] Full color digital hologram production ===Organizations=== *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.holography.co.uk/index.shtml Royal Photographic Society] *[http://www.spie.org The International Society for Optical Engineering] *[http://www.IHMA.org International Hologram Manufacturers Association] *[http://www.holographynews.info Holography News - Industry information] b6190b584a18820cfc53531e35b95c75973116bb 6 1218 2550 2014-04-08T01:49:46Z Jsfisher 1 Filipe Alves tries his hand at experimenting with an albumen emulsion. wikitext text/x-wiki Filipe Alves tries his hand at experimenting with an albumen emulsion. c338ec21d46d8064f17be76e34431b5893e5a12c 2560 2550 2014-04-08T02:53:45Z Jsfisher 1 Jsfisher uploaded a new version of &quot;[[File:Holograms made with albumen emulsion.mp4]]&quot; wikitext text/x-wiki Filipe Alves tries his hand at experimenting with an albumen emulsion. c338ec21d46d8064f17be76e34431b5893e5a12c 0 489 2551 2490 2014-04-08T01:51:11Z Jsfisher 1 wikitext text/x-wiki <DirList>docs</dirlist> http://abc.def.com/asdf Text [[Image:Holograms made with albumen emulsion.mp4]] <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} [[Sandbox / Subsandbox]] This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== [[User:Jsfisher|/jsfisher]] ([[User talk:Jsfisher|talk]]) 23:19, 25 June 2013 (EDT) ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y} scriptscriptstyle</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> 4a6d62403e63942b2bc7f297674b000403d8e4db 2552 2551 2014-04-08T02:14:51Z Jsfisher 1 wikitext text/x-wiki <DirList>docs</dirlist> http://abc.def.com/asdf Text <html5media height="360" width="640">File:Holograms made with albumen emulsion.mp4</html5media> <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} [[Sandbox / Subsandbox]] This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== [[User:Jsfisher|/jsfisher]] ([[User talk:Jsfisher|talk]]) 23:19, 25 June 2013 (EDT) ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y} scriptscriptstyle</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> fc4afb556b17a660a7b7db00e100b90c07254ca7 2563 2552 2014-04-20T14:27:53Z Jsfisher 1 wikitext text/x-wiki <DirList>docs</dirlist> http://abc.def.com/asdf Text <html5media height="180" width="320">File:Holograms made with albumen emulsion.mp4</html5media> <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} [[Sandbox / Subsandbox]] This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== [[User:Jsfisher|/jsfisher]] ([[User talk:Jsfisher|talk]]) 23:19, 25 June 2013 (EDT) ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y} scriptscriptstyle</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> c87073386431ce381523bbd9532efbb71963dbd4 0 866 2553 2130 2014-04-08T02:19:15Z Jsfisher 1 wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Albumen Emulsion Plates == Filipe Alves has a go at making albumen emulsion plates. See http://www.holoforum.org/forum/viewtopic.phpt=831 <html5media height="360" width="640">File:Holograms made with albumen emulsion.mp4</html5media> == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in three Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 , http://holoforum.org/forum/viewtopic.php?f=7&t=497 , http://holoforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} 7296b1d90963aceb723d6153121eb9506b9ce7a6 2554 2553 2014-04-08T02:19:59Z Jsfisher 1 /* Albumen Emulsion Plates */ wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Albumen Emulsion Plates == Filipe Alves has a go at making albumen emulsion plates. See http://www.holoforum.org/forum/viewtopic.php&t=831 <html5media height="360" width="640">File:Holograms made with albumen emulsion.mp4</html5media> == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in three Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 , http://holoforum.org/forum/viewtopic.php?f=7&t=497 , http://holoforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} ca29dba3186fdc6272abb788907f5ff328abf804 2555 2554 2014-04-08T02:20:37Z Jsfisher 1 /* Albumen Emulsion Plates */ wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Albumen Emulsion Plates == Filipe Alves has a go at making albumen emulsion plates. See http://www.holoforum.org/forum/viewtopic.php?t=831 <html5media height="360" width="640">File:Holograms made with albumen emulsion.mp4</html5media> == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in three Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 , http://holoforum.org/forum/viewtopic.php?f=7&t=497 , http://holoforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} d3d70686c137d4fddca34fd67a0b2029b26d8148 2558 2555 2014-04-08T02:30:26Z Jsfisher 1 /* Albumen Emulsion Plates */ wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Albumen Emulsion Plates == Filipe Alves has a go at making albumen emulsion plates. See http://www.holoforum.org/forum/viewtopic.php?t=831 Click on the ''play button'' to start the video: <html5media height="360" width="640">File:Holograms made with albumen emulsion.mp4</html5media> == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in three Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 , http://holoforum.org/forum/viewtopic.php?f=7&t=497 , http://holoforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} 6518a961c10c64492578eddb7af64032ecd3776b 2559 2558 2014-04-08T02:30:57Z Jsfisher 1 /* Albumen Emulsion Plates */ wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Albumen Emulsion Plates == Filipe Alves has a go at making albumen emulsion plates. See http://www.holoforum.org/forum/viewtopic.php?t=831 Click on the '''play button''' to start the video: <html5media height="360" width="640">File:Holograms made with albumen emulsion.mp4</html5media> == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in three Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 , http://holoforum.org/forum/viewtopic.php?f=7&t=497 , http://holoforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-bloom pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} d6b0a30f4b1917df44ac0804648f32f81e9ebaf7 0 820 2562 2142 2014-04-19T16:36:21Z Jsfisher 1 /* Basics */ wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right|Hologram by John Fisher]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques, John Fisher. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. They are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if the hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. A common method to seal the hologram is to epoxy a second glass plate to the back of the hologram plate, thereby protecting it from moisture. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html [[Category:DCG]] [[Category:Beginner]] c9fdb13a50d34c0f0a7b156fd1ab4dc29f0504b8 0 808 2567 2189 2014-04-20T19:28:56Z Jsfisher 1 wikitext text/x-wiki {{#seo:|description=Holography for the newcomer}} [[Image:Sandbox_Kit.jpg|right]]The "original" hobbyist's approach to holography was described in the May 1979 issue of ''Physics Education'' as the aptly named ''Sandbox Holography''. Metrologic produced and sold an identically named kit. The kit included some holographic film, chemicals for processing the film, and few lenses and mirrors. Not included were the laser (and at the time, that meant a moderately pricey helium-neon gas laser) nor the sandbox. Holography is extremely sensitive to movement, even microscopic movement, during the exposure. In conventional photography, movement will blur the image. With a hologram, since movement would completely alter the interference pattern between the direct and reflected laser light, the image can be lost completely. The sandbox was used to help eliminate vibration. In the late 1970's and early 1980's, the Metrologic Instruments Sandbox Holography kit might have cost you $150(US). A suitable laser, another $400 or so, and by the time you had the sandbox set up, you would be out $600 to $700 in 1980 dollars. For the curious, an updated version of the kit is still available from [http://i-fiberoptics.com/laser-kits-projects-detail.php?id=2140 Industrial Fiber Optics]. Industrial Fiber Optics purchased the educational laser and kit product line from Metrologic Instruments in November 2004. Although the [http://i-fiberoptics.com/pdf/45-733a_manual-revc.pdf Sandbox Holography] manual has details specific to the sandbox kit, it still provides a general introduction to holography for the beginner. == Modern Beginner's Kit == [[Image:Integraf_kit.jpg|right]]Diode lasers, like the ones found in common laser pointers, have completely changed what is needed for a suitable beginner's kit. You still need film and processing chemicals, but your first hologram can be made with no additional lenses or mirrors (because the diode laser beam naturally spreads), and there are some simple techniques developed over the years since the Sandbox kit was first introduced to eliminate the sandbox. In the new era, sandbox holography has evolved into [http://www.holoworld.com/shoebox/ Shoebox Holography], and there are now three, relatively economic ways for novice holographers to begin their hobby. #Buy the ''Shoebox Holography'' book. With that as a guide (or the equivalent information scoured from the Internet) acquire a suitable laser, holographic film, and chemicals and have at it. #Acquire one of the kits available from [http://www.integraf.com/holography_kit.htm Integraf]. (Film is more difficult to work with than glass plates, so the Standard or Student Kit is much preferred over the Budget Kit.) #Acquire a different type of kit from [http://www.litiholo.com Litiholo]. For the truly novice holographer, the Litiholo kit is a a bit of an oddity. With it, you can produce your first, interesting hologram. The kit comes with 20 plates, so there is plenty of opportunity for experimentation and the inevitable failure. Be aware, though, it is a self-contained unit. The holographic plates are self-developing, and the configuration is limited to the setups the kit intended. For the mildly curious individual or the elementary school aged child, the Litiholo kit is fabulous. For the slightly experienced holographer, it is good, if for nothing else than the exposure to polymer photo-materials. For the true beginner, though, it is a little like buying a TV dinner because you wanted to learn to cook. There is not enough "participation" to engage the beginner. Of the remaining two choices, simply buying a kit from Integraf saves you all the hassle of acquiring the parts individually. Plus you end up with a higher quality laser than what you would get from an ordinary laser pointer. Some laser pointers have stability issues that may be unnoticeable in normal use, but disastrous in holography. The information that comes with the Integraf kit, or the identical [http://www.integraf.com/a-simple_holography.htm material available from the Integraf web site], or similar articles online, or from texts like the ''Shoebox Holography'' book, covers what to do next. Not much to it, really. == Beginner's FAQ == ; What is a hologram? : Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ; How little money/bother do I need to make one? : You can make your first hologram with about 2 hours of set up and about $100. ; What is the cheapest way to make a hologram? : [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ; Are the chemicals dangerous? : While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ; What sort of time commitment is there for making a hologram? : You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ; When can I have the lights 'on' during the procedure of making a hologram? : Once the emulsion has become insensitive to to light. For silver-halide holograms this is after the hologram is bleached. For dichromated gelatin holograms this is after the fixing and rinsing steps. ; What are the different kinds of holograms? : [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ; What is the single most important factor when making a hologram? : ''Stability!'' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ; How Does a LASER work? : For a simple introduction to lasers read [[How Do LASERs work?]]. ; Can I use a cheap red laser pointer to make holograms? : Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ; Can I use a Green Laser Pointer to make holograms? : So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ; Where are the Reference and Object beams in a Single Beam Reflection Hologram? : Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ; Some uses for [[Everyday Items]] in holography : Click here for [[Everyday Items]] that can save you money in holography! ; What is a [[Scratch-O-Gram]]? : A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and focusing it from a curved scratch to a point. ; What Books are Available for Holography? : See the [[Books]] section. [[Category:Beginner]] 540a6b836ce4e90f3498895bdaa8969186cafa8e 2568 2567 2014-04-20T22:30:38Z Jsfisher 1 wikitext text/x-wiki {{#seo:|description=How to get started making your own holograms}} [[Image:Sandbox_Kit.jpg|right]]The "original" hobbyist's approach to holography was described in the May 1979 issue of ''Physics Education'' as the aptly named ''Sandbox Holography''. Metrologic produced and sold an identically named kit. The kit included some holographic film, chemicals for processing the film, and few lenses and mirrors. Not included were the laser (and at the time, that meant a moderately pricey helium-neon gas laser) nor the sandbox. Holography is extremely sensitive to movement, even microscopic movement, during the exposure. In conventional photography, movement will blur the image. With a hologram, since movement would completely alter the interference pattern between the direct and reflected laser light, the image can be lost completely. The sandbox was used to help eliminate vibration. In the late 1970's and early 1980's, the Metrologic Instruments Sandbox Holography kit might have cost you $150(US). A suitable laser, another $400 or so, and by the time you had the sandbox set up, you would be out $600 to $700 in 1980 dollars. For the curious, an updated version of the kit is still available from [http://i-fiberoptics.com/laser-kits-projects-detail.php?id=2140 Industrial Fiber Optics]. Industrial Fiber Optics purchased the educational laser and kit product line from Metrologic Instruments in November 2004. Although the [http://i-fiberoptics.com/pdf/45-733a_manual-revc.pdf Sandbox Holography] manual has details specific to the sandbox kit, it still provides a general introduction to holography for the beginner. == Modern Beginner's Kit == [[Image:Integraf_kit.jpg|right]]Diode lasers, like the ones found in common laser pointers, have completely changed what is needed for a suitable beginner's kit. You still need film and processing chemicals, but your first hologram can be made with no additional lenses or mirrors (because the diode laser beam naturally spreads), and there are some simple techniques developed over the years since the Sandbox kit was first introduced to eliminate the sandbox. In the new era, sandbox holography has evolved into [http://www.holoworld.com/shoebox/ Shoebox Holography], and there are now three, relatively economic ways for novice holographers to begin their hobby. #Buy the ''Shoebox Holography'' book. With that as a guide (or the equivalent information scoured from the Internet) acquire a suitable laser, holographic film, and chemicals and have at it. #Acquire one of the kits available from [http://www.integraf.com/holography_kit.htm Integraf]. (Film is more difficult to work with than glass plates, so the Standard or Student Kit is much preferred over the Budget Kit.) #Acquire a different type of kit from [http://www.litiholo.com Litiholo]. For the truly novice holographer, the Litiholo kit is a a bit of an oddity. With it, you can produce your first, interesting hologram. The kit comes with 20 plates, so there is plenty of opportunity for experimentation and the inevitable failure. Be aware, though, it is a self-contained unit. The holographic plates are self-developing, and the configuration is limited to the setups the kit intended. For the mildly curious individual or the elementary school aged child, the Litiholo kit is fabulous. For the slightly experienced holographer, it is good, if for nothing else than the exposure to polymer photo-materials. For the true beginner, though, it is a little like buying a TV dinner because you wanted to learn to cook. There is not enough "participation" to engage the beginner. Of the remaining two choices, simply buying a kit from Integraf saves you all the hassle of acquiring the parts individually. Plus you end up with a higher quality laser than what you would get from an ordinary laser pointer. Some laser pointers have stability issues that may be unnoticeable in normal use, but disastrous in holography. The information that comes with the Integraf kit, or the identical [http://www.integraf.com/a-simple_holography.htm material available from the Integraf web site], or similar articles online, or from texts like the ''Shoebox Holography'' book, covers what to do next. Not much to it, really. == Beginner's FAQ == ; What is a hologram? : Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ; How little money/bother do I need to make one? : You can make your first hologram with about 2 hours of set up and about $100. ; What is the cheapest way to make a hologram? : [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ; Are the chemicals dangerous? : While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ; What sort of time commitment is there for making a hologram? : You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ; When can I have the lights 'on' during the procedure of making a hologram? : Once the emulsion has become insensitive to to light. For silver-halide holograms this is after the hologram is bleached. For dichromated gelatin holograms this is after the fixing and rinsing steps. ; What are the different kinds of holograms? : [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ; What is the single most important factor when making a hologram? : ''Stability!'' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ; How Does a LASER work? : For a simple introduction to lasers read [[How Do LASERs work?]]. ; Can I use a cheap red laser pointer to make holograms? : Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ; Can I use a Green Laser Pointer to make holograms? : So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ; Where are the Reference and Object beams in a Single Beam Reflection Hologram? : Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ; Some uses for [[Everyday Items]] in holography : Click here for [[Everyday Items]] that can save you money in holography! ; What is a [[Scratch-O-Gram]]? : A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and focusing it from a curved scratch to a point. ; What Books are Available for Holography? : See the [[Books]] section. [[Category:Beginner]] cf748e394b9c75a28a1acbc60c791e8c046383bf 4 1219 2569 2014-04-22T00:37:08Z Jsfisher 1 Created page with "==General Scope== This policy covers personally identifiable information collected or stored by the server for the Holowiki web site. Consistent with the site's purpose, the l..." wikitext text/x-wiki ==General Scope== This policy covers personally identifiable information collected or stored by the server for the Holowiki web site. Consistent with the site's purpose, the least amount of personally identifiable information needed to fulfill the site's operational needs is collected. ==The public and collaborative nature of the site== All content of the Holowiki web site were collaboratively developed or provided by its users using the MediaWiki software. Anyone with Internet access (and not otherwise restricted from doing so) may view the publicly available pages with or without logging in as a registered user. However, users must log in to edit the Holowiki content. By editing existing or entering new content, editors create a published document, and a public record of every word added, subtracted, or changed. This is a public act, and editors are identified publicly as the author of such changes. All contributions made to Holowiki, and all publicly available information about those contributions, are irrevocably licensed and may be freely copied, quoted, reused and adapted by third parties with few restrictions. ==Activities on Holowiki== In general, this Policy only applies to private information stored or held by the Holowiki server which is not publicly available. Interactions with the Holowiki site not covered by this Policy include, but are not limited to, aspects of browsing and editing pages and use of the wiki "email user" function. These interactions may reveal a contributor's IP address, and possibly other personal information, indiscriminately to the general public. ==User accounts and authorship== The Holowiki site does require editors to register with the site. Editors are identified by their chosen username. Users select a password, which is confidential and used to verify the integrity of their account. Except insofar as it may be required by law, no person should disclose, or knowingly expose, either user passwords or cookies generated to identify a user. Once created, user accounts will not be removed except under rare circumstances involving disruptive behvior. It may be possible for a username to be changed, but there is no guarantee that a username will be changed on request. ==Purpose of the collection of private information== The Holowiki limits the collection of personally identifiable user data to purposes which serve the well-being of the site and its purpose, including but not limited to the following: * '''To enhance the public accountability of the projects.''' It is recognized that any system that is open enough to allow the participation of the general public will also be vulnerable to certain kinds of abuse and counterproductive behavior. The Holowiki site has established a number of mechanisms to prevent or remedy abusive activities. For example, when investigating abuse on a project, including the suspected use of malicious “sockpuppets” (duplicate accounts), vandalism, harassment of other users, or disruptive behavior, the IP addresses of users (derived either from those logs or from records in the database) may be used to identify the source(s) of the abusive behavior. This information may be shared with Internet Service Providers and possibly law enforcement agencies. * '''To provide site statistics.''' The Holowiki administrator statistically samples raw log data from users' visits. These logs may be used to produce site statistics pages; the raw log data is not made public. * '''To solve technical problems.''' Log data may be examined in the course of solving technical problems and in tracking down badly-behaved web spiders that overwhelm the site. ==Details of data retention== ===General expectations=== ;IP and other technical information :When a visitor requests or reads a page, or sends email via the Holowiki server, no more information is collected than is typically collected by web sites. Logs may be kept of such transactions, but these will not be published or used to track legitimate users. ;Cookies :The sites set a temporary session cookie on a visitor's computer whenever a Holowiki page is visited. Readers who do not intend to log in or edit may deny this cookie; it will be deleted at the end of the browser's session. More cookies may be set when one logs in to maintain logged-in status. If one saves a user name or password in one's browser, that information will be saved for up to 30 days, and this information will be resent to the server on every visit to the same Project. ;Page history :Edits or other contributions to the Holowiki on its articles, user pages and talk pages are generally retained forever. Removing text does not permanently delete it. Normally, anyone can look at a previous version of an article and see what was there. Even if an article is "deleted", a user entrusted with higher level of access may still see what was removed from public view. Information can be permanently deleted by individuals with access to the Holowiki server, but aside from the rare circumstance when it is required that editing-history material be deleted in response to a court order or equivalent legal process, there is no guarantee any permanent deletion will happen. ;User contribution :User contributions are also aggregated and publicly available. User contributions are aggregated according to their registration and login status. Data on user contributions, such as the times at which users edited and the number of edits they have made, are publicly available via user contributions lists, and in aggregated forms published by other users. ;Reading content :No more information on users and other visitors reading pages is collected than is typically collected in server logs by web sites. Aside from the above raw log data collected for general purposes, page visits do not expose a visitor's identity publicly. Sampled raw log data may include the IP address of any user, but it is not reproduced publicly. ;Editing content :Edits to Holowiki pages are identified with the username of the editor, and editing history is aggregated by author in a contribution list. Such information will be available permanently on the projects. Logged in users do not expose their IP address to the public except in cases of abuse, including vandalism of a Holowiki page by the user or by another user with the same IP address. A user's IP address is stored on the Holowiki server for a period of time, during which it can be seen by server administrators and by users who have been granted CheckUser access. IP address information, and its connection to any usernames that share it, may be released under certain circumstances (see below). ;Discussions :''On wiki discussion pages:'' Any editable page can theoretically be the location of a discussion. In general, discussions on Holowiki occur on user talk pages (associated with particular users) or on article talk pages (associated with particular articles). Privacy expectations apply to discussion pages in the same way as they do elsewhere. ''Via email:'' Users are not required to list an email address when registering. Users who provide a valid email address can enable other logged-in users to send email to them through Holowiki. When receiving an email from other users through this system, one's email address is not revealed to them. When choosing to send an email to other users, one's email is displayed as the sender. The email address put into one's user preferences may be used by the Holowiki administration for communication. Users whose accounts do not have a valid email address will not be able to reset their password if it is lost. In such a situation, however, users may be able to contact the Holowiki administration to enter a new e-mail address. A user can remove the account's email address from his preferences at any time to prevent it from being used. Private correspondence between users may be saved at those users' discretion and is not subject to Holowiki policy. ==Release of personally identifiable information== It is the policy of Holowiki that personally identifiable data collected in the server logs, or through records in the database via the CheckUser feature, or through other non-publicly-available methods, may be released by Holowiki administration in any of the following situations: * In response to a valid subpoena or other compulsory request from law enforcement, * With permission of the affected user, * When necessary for investigation of abuse complaints, * Where the information pertains to page views generated by a spider or bot and its dissemination is necessary to illustrate or resolve technical issues, * Where the user has been vandalizing articles or persistently behaving in a disruptive way, data may be released to a service provider, carrier, or other third-party entity to assist in the targeting of IP blocks, or to assist in the formulation of a complaint to relevant Internet Service Providers, * Where it is reasonably necessary to protect the rights, property or safety of the Holowiki, its users or the public. Except as described above, Holowiki policy does not permit distribution of personally identifiable information under any circumstances. ===Third-party access and notifying registered users when receiving legal process=== As a general principle, the access to, and retention of, personally identifiable data should be minimal and should be used only internally to serve the well-being of Holowiki. Occasionally, however, the Holowiki administration may receive a subpoena or other compulsory request from a law-enforcement agency or a court or equivalent government body that requests the disclosure of information about a registered user, and may be compelled by law to comply with the request. In the event of such a legally compulsory request, the Foundation will attempt to notify the affected user within three business days after the arrival of such subpoena by sending a notice by email to the email address (if any) that the affected user has listed in his or her user preferences. The administration cannot advise a user receiving such a notification regarding the law or an appropriate response to a subpoena. The administration does note, however, that such users may have the legal right to resist or limit that information in court by filing a motion to quash the subpoena. Users who wish to oppose a subpoena or other compulsory request should seek legal advice concerning applicable rights and procedures that may be available. If the Holowiki administration receives a court-filed motion to quash or otherwise limit the subpoena as a result of action by a user or their lawyer, the Holowiki administration will not disclose the requested information until it receives an order from the court to do so. Registered users are not required to provide an email address. However, when an affected registered user does not provide an email address, the Holowiki administration will not be able to notify the affected user in private email messages when it receives requests from law enforcement to disclose personally identifiable information about the user. ==Disclaimer== The Holowiki administration believes that maintaining and preserving the privacy of user data is an important value. This Privacy Policy, together with other policies, resolutions, and actions by Holowiki, represents a committed effort to safeguard the security of the limited user information that is collected and retained on our servers. Nevertheless, the Holowiki cannot guarantee that user information will remain private. We acknowledge that, in spite of our committed effort to protect private user information, determined individuals may still develop data-mining and other methods to uncover such information and disclose it. For this reason, the Holowiki can make no guarantee against unauthorized access to information provided in the course of participating in Holowiki activities. a9d30171e5a93d2e709ee3a5abf68edc4f8d40fd 2570 2569 2014-04-22T00:38:55Z Jsfisher 1 /* General expectations */ wikitext text/x-wiki ==General Scope== This policy covers personally identifiable information collected or stored by the server for the Holowiki web site. Consistent with the site's purpose, the least amount of personally identifiable information needed to fulfill the site's operational needs is collected. ==The public and collaborative nature of the site== All content of the Holowiki web site were collaboratively developed or provided by its users using the MediaWiki software. Anyone with Internet access (and not otherwise restricted from doing so) may view the publicly available pages with or without logging in as a registered user. However, users must log in to edit the Holowiki content. By editing existing or entering new content, editors create a published document, and a public record of every word added, subtracted, or changed. This is a public act, and editors are identified publicly as the author of such changes. All contributions made to Holowiki, and all publicly available information about those contributions, are irrevocably licensed and may be freely copied, quoted, reused and adapted by third parties with few restrictions. ==Activities on Holowiki== In general, this Policy only applies to private information stored or held by the Holowiki server which is not publicly available. Interactions with the Holowiki site not covered by this Policy include, but are not limited to, aspects of browsing and editing pages and use of the wiki "email user" function. These interactions may reveal a contributor's IP address, and possibly other personal information, indiscriminately to the general public. ==User accounts and authorship== The Holowiki site does require editors to register with the site. Editors are identified by their chosen username. Users select a password, which is confidential and used to verify the integrity of their account. Except insofar as it may be required by law, no person should disclose, or knowingly expose, either user passwords or cookies generated to identify a user. Once created, user accounts will not be removed except under rare circumstances involving disruptive behvior. It may be possible for a username to be changed, but there is no guarantee that a username will be changed on request. ==Purpose of the collection of private information== The Holowiki limits the collection of personally identifiable user data to purposes which serve the well-being of the site and its purpose, including but not limited to the following: * '''To enhance the public accountability of the projects.''' It is recognized that any system that is open enough to allow the participation of the general public will also be vulnerable to certain kinds of abuse and counterproductive behavior. The Holowiki site has established a number of mechanisms to prevent or remedy abusive activities. For example, when investigating abuse on a project, including the suspected use of malicious “sockpuppets” (duplicate accounts), vandalism, harassment of other users, or disruptive behavior, the IP addresses of users (derived either from those logs or from records in the database) may be used to identify the source(s) of the abusive behavior. This information may be shared with Internet Service Providers and possibly law enforcement agencies. * '''To provide site statistics.''' The Holowiki administrator statistically samples raw log data from users' visits. These logs may be used to produce site statistics pages; the raw log data is not made public. * '''To solve technical problems.''' Log data may be examined in the course of solving technical problems and in tracking down badly-behaved web spiders that overwhelm the site. ==Details of data retention== ===General expectations=== ;IP and other technical information :When a visitor requests or reads a page, or sends email via the Holowiki server, no more information is collected than is typically collected by web sites. Logs may be kept of such transactions, but these will not be published or used to track legitimate users. ;Cookies :The sites set a temporary session cookie on a visitor's computer whenever a Holowiki page is visited. Readers who do not intend to log in or edit may deny this cookie; it will be deleted at the end of the browser's session. More cookies may be set when one logs in to maintain logged-in status. If one saves a user name or password in one's browser, that information will be saved for up to 30 days, and this information will be resent to the server on every visit to the same Project. ;Page history :Edits or other contributions to the Holowiki on its articles, user pages and talk pages are generally retained forever. Removing text does not permanently delete it. Normally, anyone can look at a previous version of an article and see what was there. Even if an article is "deleted", a user entrusted with higher level of access may still see what was removed from public view. Information can be permanently deleted by individuals with access to the Holowiki server, but aside from the rare circumstance when it is required that editing-history material be deleted in response to a court order or equivalent legal process, there is no guarantee any permanent deletion will happen. ;User contribution :User contributions are also aggregated and publicly available. User contributions are aggregated according to their registration and login status. Data on user contributions, such as the times at which users edited and the number of edits they have made, are publicly available via user contributions lists, and in aggregated forms published by other users. ;Reading content :No more information on users and other visitors reading pages is collected than is typically collected in server logs by web sites. Aside from the above raw log data collected for general purposes, page visits do not expose a visitor's identity publicly. Sampled raw log data may include the IP address of any user, but it is not reproduced publicly. ;Editing content :Edits to Holowiki pages are identified with the username of the editor, and editing history is aggregated by author in a contribution list. Such information will be available permanently on the projects. Logged in users do not expose their IP address to the public except in cases of abuse, including vandalism of a Holowiki page by the user or by another user with the same IP address. A user's IP address is stored on the Holowiki server for a period of time, during which it can be seen by server administrators and by users who have been granted CheckUser access. :IP address information, and its connection to any usernames that share it, may be released under certain circumstances (see below). ;Discussions :''On wiki discussion pages:'' Any editable page can theoretically be the location of a discussion. In general, discussions on Holowiki occur on user talk pages (associated with particular users) or on article talk pages (associated with particular articles). Privacy expectations apply to discussion pages in the same way as they do elsewhere. :''Via email:'' Users are not required to list an email address when registering. Users who provide a valid email address can enable other logged-in users to send email to them through Holowiki. When receiving an email from other users through this system, one's email address is not revealed to them. When choosing to send an email to other users, one's email is displayed as the sender. The email address put into one's user preferences may be used by the Holowiki administration for communication. Users whose accounts do not have a valid email address will not be able to reset their password if it is lost. In such a situation, however, users may be able to contact the Holowiki administration to enter a new e-mail address. A user can remove the account's email address from his preferences at any time to prevent it from being used. Private correspondence between users may be saved at those users' discretion and is not subject to Holowiki policy. ==Release of personally identifiable information== It is the policy of Holowiki that personally identifiable data collected in the server logs, or through records in the database via the CheckUser feature, or through other non-publicly-available methods, may be released by Holowiki administration in any of the following situations: * In response to a valid subpoena or other compulsory request from law enforcement, * With permission of the affected user, * When necessary for investigation of abuse complaints, * Where the information pertains to page views generated by a spider or bot and its dissemination is necessary to illustrate or resolve technical issues, * Where the user has been vandalizing articles or persistently behaving in a disruptive way, data may be released to a service provider, carrier, or other third-party entity to assist in the targeting of IP blocks, or to assist in the formulation of a complaint to relevant Internet Service Providers, * Where it is reasonably necessary to protect the rights, property or safety of the Holowiki, its users or the public. Except as described above, Holowiki policy does not permit distribution of personally identifiable information under any circumstances. ===Third-party access and notifying registered users when receiving legal process=== As a general principle, the access to, and retention of, personally identifiable data should be minimal and should be used only internally to serve the well-being of Holowiki. Occasionally, however, the Holowiki administration may receive a subpoena or other compulsory request from a law-enforcement agency or a court or equivalent government body that requests the disclosure of information about a registered user, and may be compelled by law to comply with the request. In the event of such a legally compulsory request, the Foundation will attempt to notify the affected user within three business days after the arrival of such subpoena by sending a notice by email to the email address (if any) that the affected user has listed in his or her user preferences. The administration cannot advise a user receiving such a notification regarding the law or an appropriate response to a subpoena. The administration does note, however, that such users may have the legal right to resist or limit that information in court by filing a motion to quash the subpoena. Users who wish to oppose a subpoena or other compulsory request should seek legal advice concerning applicable rights and procedures that may be available. If the Holowiki administration receives a court-filed motion to quash or otherwise limit the subpoena as a result of action by a user or their lawyer, the Holowiki administration will not disclose the requested information until it receives an order from the court to do so. Registered users are not required to provide an email address. However, when an affected registered user does not provide an email address, the Holowiki administration will not be able to notify the affected user in private email messages when it receives requests from law enforcement to disclose personally identifiable information about the user. ==Disclaimer== The Holowiki administration believes that maintaining and preserving the privacy of user data is an important value. This Privacy Policy, together with other policies, resolutions, and actions by Holowiki, represents a committed effort to safeguard the security of the limited user information that is collected and retained on our servers. Nevertheless, the Holowiki cannot guarantee that user information will remain private. We acknowledge that, in spite of our committed effort to protect private user information, determined individuals may still develop data-mining and other methods to uncover such information and disclose it. For this reason, the Holowiki can make no guarantee against unauthorized access to information provided in the course of participating in Holowiki activities. f636347094955436f3cf8f54e6c308575cb100fe 2571 2570 2014-04-22T00:39:49Z Jsfisher 1 /* General expectations */ wikitext text/x-wiki ==General Scope== This policy covers personally identifiable information collected or stored by the server for the Holowiki web site. Consistent with the site's purpose, the least amount of personally identifiable information needed to fulfill the site's operational needs is collected. ==The public and collaborative nature of the site== All content of the Holowiki web site were collaboratively developed or provided by its users using the MediaWiki software. Anyone with Internet access (and not otherwise restricted from doing so) may view the publicly available pages with or without logging in as a registered user. However, users must log in to edit the Holowiki content. By editing existing or entering new content, editors create a published document, and a public record of every word added, subtracted, or changed. This is a public act, and editors are identified publicly as the author of such changes. All contributions made to Holowiki, and all publicly available information about those contributions, are irrevocably licensed and may be freely copied, quoted, reused and adapted by third parties with few restrictions. ==Activities on Holowiki== In general, this Policy only applies to private information stored or held by the Holowiki server which is not publicly available. Interactions with the Holowiki site not covered by this Policy include, but are not limited to, aspects of browsing and editing pages and use of the wiki "email user" function. These interactions may reveal a contributor's IP address, and possibly other personal information, indiscriminately to the general public. ==User accounts and authorship== The Holowiki site does require editors to register with the site. Editors are identified by their chosen username. Users select a password, which is confidential and used to verify the integrity of their account. Except insofar as it may be required by law, no person should disclose, or knowingly expose, either user passwords or cookies generated to identify a user. Once created, user accounts will not be removed except under rare circumstances involving disruptive behvior. It may be possible for a username to be changed, but there is no guarantee that a username will be changed on request. ==Purpose of the collection of private information== The Holowiki limits the collection of personally identifiable user data to purposes which serve the well-being of the site and its purpose, including but not limited to the following: * '''To enhance the public accountability of the projects.''' It is recognized that any system that is open enough to allow the participation of the general public will also be vulnerable to certain kinds of abuse and counterproductive behavior. The Holowiki site has established a number of mechanisms to prevent or remedy abusive activities. For example, when investigating abuse on a project, including the suspected use of malicious “sockpuppets” (duplicate accounts), vandalism, harassment of other users, or disruptive behavior, the IP addresses of users (derived either from those logs or from records in the database) may be used to identify the source(s) of the abusive behavior. This information may be shared with Internet Service Providers and possibly law enforcement agencies. * '''To provide site statistics.''' The Holowiki administrator statistically samples raw log data from users' visits. These logs may be used to produce site statistics pages; the raw log data is not made public. * '''To solve technical problems.''' Log data may be examined in the course of solving technical problems and in tracking down badly-behaved web spiders that overwhelm the site. ==Details of data retention== ;IP and other technical information :When a visitor requests or reads a page, or sends email via the Holowiki server, no more information is collected than is typically collected by web sites. Logs may be kept of such transactions, but these will not be published or used to track legitimate users. ;Cookies :The sites set a temporary session cookie on a visitor's computer whenever a Holowiki page is visited. Readers who do not intend to log in or edit may deny this cookie; it will be deleted at the end of the browser's session. More cookies may be set when one logs in to maintain logged-in status. If one saves a user name or password in one's browser, that information will be saved for up to 30 days, and this information will be resent to the server on every visit to the same Project. ;Page history :Edits or other contributions to the Holowiki on its articles, user pages and talk pages are generally retained forever. Removing text does not permanently delete it. Normally, anyone can look at a previous version of an article and see what was there. Even if an article is "deleted", a user entrusted with higher level of access may still see what was removed from public view. Information can be permanently deleted by individuals with access to the Holowiki server, but aside from the rare circumstance when it is required that editing-history material be deleted in response to a court order or equivalent legal process, there is no guarantee any permanent deletion will happen. ;User contribution :User contributions are also aggregated and publicly available. User contributions are aggregated according to their registration and login status. Data on user contributions, such as the times at which users edited and the number of edits they have made, are publicly available via user contributions lists, and in aggregated forms published by other users. ;Reading content :No more information on users and other visitors reading pages is collected than is typically collected in server logs by web sites. Aside from the above raw log data collected for general purposes, page visits do not expose a visitor's identity publicly. Sampled raw log data may include the IP address of any user, but it is not reproduced publicly. ;Editing content :Edits to Holowiki pages are identified with the username of the editor, and editing history is aggregated by author in a contribution list. Such information will be available permanently on the projects. Logged in users do not expose their IP address to the public except in cases of abuse, including vandalism of a Holowiki page by the user or by another user with the same IP address. A user's IP address is stored on the Holowiki server for a period of time, during which it can be seen by server administrators and by users who have been granted CheckUser access. :IP address information, and its connection to any usernames that share it, may be released under certain circumstances (see below). ;Discussions :''On wiki discussion pages:'' Any editable page can theoretically be the location of a discussion. In general, discussions on Holowiki occur on user talk pages (associated with particular users) or on article talk pages (associated with particular articles). Privacy expectations apply to discussion pages in the same way as they do elsewhere. :''Via email:'' Users are not required to list an email address when registering. Users who provide a valid email address can enable other logged-in users to send email to them through Holowiki. When receiving an email from other users through this system, one's email address is not revealed to them. When choosing to send an email to other users, one's email is displayed as the sender. The email address put into one's user preferences may be used by the Holowiki administration for communication. Users whose accounts do not have a valid email address will not be able to reset their password if it is lost. In such a situation, however, users may be able to contact the Holowiki administration to enter a new e-mail address. A user can remove the account's email address from his preferences at any time to prevent it from being used. Private correspondence between users may be saved at those users' discretion and is not subject to Holowiki policy. ==Release of personally identifiable information== It is the policy of Holowiki that personally identifiable data collected in the server logs, or through records in the database via the CheckUser feature, or through other non-publicly-available methods, may be released by Holowiki administration in any of the following situations: * In response to a valid subpoena or other compulsory request from law enforcement, * With permission of the affected user, * When necessary for investigation of abuse complaints, * Where the information pertains to page views generated by a spider or bot and its dissemination is necessary to illustrate or resolve technical issues, * Where the user has been vandalizing articles or persistently behaving in a disruptive way, data may be released to a service provider, carrier, or other third-party entity to assist in the targeting of IP blocks, or to assist in the formulation of a complaint to relevant Internet Service Providers, * Where it is reasonably necessary to protect the rights, property or safety of the Holowiki, its users or the public. Except as described above, Holowiki policy does not permit distribution of personally identifiable information under any circumstances. ===Third-party access and notifying registered users when receiving legal process=== As a general principle, the access to, and retention of, personally identifiable data should be minimal and should be used only internally to serve the well-being of Holowiki. Occasionally, however, the Holowiki administration may receive a subpoena or other compulsory request from a law-enforcement agency or a court or equivalent government body that requests the disclosure of information about a registered user, and may be compelled by law to comply with the request. In the event of such a legally compulsory request, the Foundation will attempt to notify the affected user within three business days after the arrival of such subpoena by sending a notice by email to the email address (if any) that the affected user has listed in his or her user preferences. The administration cannot advise a user receiving such a notification regarding the law or an appropriate response to a subpoena. The administration does note, however, that such users may have the legal right to resist or limit that information in court by filing a motion to quash the subpoena. Users who wish to oppose a subpoena or other compulsory request should seek legal advice concerning applicable rights and procedures that may be available. If the Holowiki administration receives a court-filed motion to quash or otherwise limit the subpoena as a result of action by a user or their lawyer, the Holowiki administration will not disclose the requested information until it receives an order from the court to do so. Registered users are not required to provide an email address. However, when an affected registered user does not provide an email address, the Holowiki administration will not be able to notify the affected user in private email messages when it receives requests from law enforcement to disclose personally identifiable information about the user. ==Disclaimer== The Holowiki administration believes that maintaining and preserving the privacy of user data is an important value. This Privacy Policy, together with other policies, resolutions, and actions by Holowiki, represents a committed effort to safeguard the security of the limited user information that is collected and retained on our servers. Nevertheless, the Holowiki cannot guarantee that user information will remain private. We acknowledge that, in spite of our committed effort to protect private user information, determined individuals may still develop data-mining and other methods to uncover such information and disclose it. For this reason, the Holowiki can make no guarantee against unauthorized access to information provided in the course of participating in Holowiki activities. a83038037d2c5bacc447dab1062d0c9c687d0a3d 4 1220 2572 2014-04-22T00:44:05Z Jsfisher 1 Created page with "Holowiki is the knowledge base wiki form for its sister operation, http:Holoforum.org/forum. The latter is a bulletin board discussion forum for holography professionals, hob..." wikitext text/x-wiki Holowiki is the knowledge base wiki form for its sister operation, http:Holoforum.org/forum. The latter is a bulletin board discussion forum for holography professionals, hobbyists, and innocent by-standers. Holowiki is much of the collected wisdom and accomplishments posted on the forum along with other information collected from a variety of public sources. The administrator for Holowiki is John Fisher. 6c1eeb73f17e7a7a01910823f204f20c45354483 4 1219 2573 2571 2014-04-22T00:44:37Z Jsfisher 1 Protected "[[Holowiki - A Holography FAQ:Privacy policy]]" ([Edit=Allow only administrators] (indefinite) [Move=Allow only administrators] (indefinite)) wikitext text/x-wiki ==General Scope== This policy covers personally identifiable information collected or stored by the server for the Holowiki web site. Consistent with the site's purpose, the least amount of personally identifiable information needed to fulfill the site's operational needs is collected. ==The public and collaborative nature of the site== All content of the Holowiki web site were collaboratively developed or provided by its users using the MediaWiki software. Anyone with Internet access (and not otherwise restricted from doing so) may view the publicly available pages with or without logging in as a registered user. However, users must log in to edit the Holowiki content. By editing existing or entering new content, editors create a published document, and a public record of every word added, subtracted, or changed. This is a public act, and editors are identified publicly as the author of such changes. All contributions made to Holowiki, and all publicly available information about those contributions, are irrevocably licensed and may be freely copied, quoted, reused and adapted by third parties with few restrictions. ==Activities on Holowiki== In general, this Policy only applies to private information stored or held by the Holowiki server which is not publicly available. Interactions with the Holowiki site not covered by this Policy include, but are not limited to, aspects of browsing and editing pages and use of the wiki "email user" function. These interactions may reveal a contributor's IP address, and possibly other personal information, indiscriminately to the general public. ==User accounts and authorship== The Holowiki site does require editors to register with the site. Editors are identified by their chosen username. Users select a password, which is confidential and used to verify the integrity of their account. Except insofar as it may be required by law, no person should disclose, or knowingly expose, either user passwords or cookies generated to identify a user. Once created, user accounts will not be removed except under rare circumstances involving disruptive behvior. It may be possible for a username to be changed, but there is no guarantee that a username will be changed on request. ==Purpose of the collection of private information== The Holowiki limits the collection of personally identifiable user data to purposes which serve the well-being of the site and its purpose, including but not limited to the following: * '''To enhance the public accountability of the projects.''' It is recognized that any system that is open enough to allow the participation of the general public will also be vulnerable to certain kinds of abuse and counterproductive behavior. The Holowiki site has established a number of mechanisms to prevent or remedy abusive activities. For example, when investigating abuse on a project, including the suspected use of malicious “sockpuppets” (duplicate accounts), vandalism, harassment of other users, or disruptive behavior, the IP addresses of users (derived either from those logs or from records in the database) may be used to identify the source(s) of the abusive behavior. This information may be shared with Internet Service Providers and possibly law enforcement agencies. * '''To provide site statistics.''' The Holowiki administrator statistically samples raw log data from users' visits. These logs may be used to produce site statistics pages; the raw log data is not made public. * '''To solve technical problems.''' Log data may be examined in the course of solving technical problems and in tracking down badly-behaved web spiders that overwhelm the site. ==Details of data retention== ;IP and other technical information :When a visitor requests or reads a page, or sends email via the Holowiki server, no more information is collected than is typically collected by web sites. Logs may be kept of such transactions, but these will not be published or used to track legitimate users. ;Cookies :The sites set a temporary session cookie on a visitor's computer whenever a Holowiki page is visited. Readers who do not intend to log in or edit may deny this cookie; it will be deleted at the end of the browser's session. More cookies may be set when one logs in to maintain logged-in status. If one saves a user name or password in one's browser, that information will be saved for up to 30 days, and this information will be resent to the server on every visit to the same Project. ;Page history :Edits or other contributions to the Holowiki on its articles, user pages and talk pages are generally retained forever. Removing text does not permanently delete it. Normally, anyone can look at a previous version of an article and see what was there. Even if an article is "deleted", a user entrusted with higher level of access may still see what was removed from public view. Information can be permanently deleted by individuals with access to the Holowiki server, but aside from the rare circumstance when it is required that editing-history material be deleted in response to a court order or equivalent legal process, there is no guarantee any permanent deletion will happen. ;User contribution :User contributions are also aggregated and publicly available. User contributions are aggregated according to their registration and login status. Data on user contributions, such as the times at which users edited and the number of edits they have made, are publicly available via user contributions lists, and in aggregated forms published by other users. ;Reading content :No more information on users and other visitors reading pages is collected than is typically collected in server logs by web sites. Aside from the above raw log data collected for general purposes, page visits do not expose a visitor's identity publicly. Sampled raw log data may include the IP address of any user, but it is not reproduced publicly. ;Editing content :Edits to Holowiki pages are identified with the username of the editor, and editing history is aggregated by author in a contribution list. Such information will be available permanently on the projects. Logged in users do not expose their IP address to the public except in cases of abuse, including vandalism of a Holowiki page by the user or by another user with the same IP address. A user's IP address is stored on the Holowiki server for a period of time, during which it can be seen by server administrators and by users who have been granted CheckUser access. :IP address information, and its connection to any usernames that share it, may be released under certain circumstances (see below). ;Discussions :''On wiki discussion pages:'' Any editable page can theoretically be the location of a discussion. In general, discussions on Holowiki occur on user talk pages (associated with particular users) or on article talk pages (associated with particular articles). Privacy expectations apply to discussion pages in the same way as they do elsewhere. :''Via email:'' Users are not required to list an email address when registering. Users who provide a valid email address can enable other logged-in users to send email to them through Holowiki. When receiving an email from other users through this system, one's email address is not revealed to them. When choosing to send an email to other users, one's email is displayed as the sender. The email address put into one's user preferences may be used by the Holowiki administration for communication. Users whose accounts do not have a valid email address will not be able to reset their password if it is lost. In such a situation, however, users may be able to contact the Holowiki administration to enter a new e-mail address. A user can remove the account's email address from his preferences at any time to prevent it from being used. Private correspondence between users may be saved at those users' discretion and is not subject to Holowiki policy. ==Release of personally identifiable information== It is the policy of Holowiki that personally identifiable data collected in the server logs, or through records in the database via the CheckUser feature, or through other non-publicly-available methods, may be released by Holowiki administration in any of the following situations: * In response to a valid subpoena or other compulsory request from law enforcement, * With permission of the affected user, * When necessary for investigation of abuse complaints, * Where the information pertains to page views generated by a spider or bot and its dissemination is necessary to illustrate or resolve technical issues, * Where the user has been vandalizing articles or persistently behaving in a disruptive way, data may be released to a service provider, carrier, or other third-party entity to assist in the targeting of IP blocks, or to assist in the formulation of a complaint to relevant Internet Service Providers, * Where it is reasonably necessary to protect the rights, property or safety of the Holowiki, its users or the public. Except as described above, Holowiki policy does not permit distribution of personally identifiable information under any circumstances. ===Third-party access and notifying registered users when receiving legal process=== As a general principle, the access to, and retention of, personally identifiable data should be minimal and should be used only internally to serve the well-being of Holowiki. Occasionally, however, the Holowiki administration may receive a subpoena or other compulsory request from a law-enforcement agency or a court or equivalent government body that requests the disclosure of information about a registered user, and may be compelled by law to comply with the request. In the event of such a legally compulsory request, the Foundation will attempt to notify the affected user within three business days after the arrival of such subpoena by sending a notice by email to the email address (if any) that the affected user has listed in his or her user preferences. The administration cannot advise a user receiving such a notification regarding the law or an appropriate response to a subpoena. The administration does note, however, that such users may have the legal right to resist or limit that information in court by filing a motion to quash the subpoena. Users who wish to oppose a subpoena or other compulsory request should seek legal advice concerning applicable rights and procedures that may be available. If the Holowiki administration receives a court-filed motion to quash or otherwise limit the subpoena as a result of action by a user or their lawyer, the Holowiki administration will not disclose the requested information until it receives an order from the court to do so. Registered users are not required to provide an email address. However, when an affected registered user does not provide an email address, the Holowiki administration will not be able to notify the affected user in private email messages when it receives requests from law enforcement to disclose personally identifiable information about the user. ==Disclaimer== The Holowiki administration believes that maintaining and preserving the privacy of user data is an important value. This Privacy Policy, together with other policies, resolutions, and actions by Holowiki, represents a committed effort to safeguard the security of the limited user information that is collected and retained on our servers. Nevertheless, the Holowiki cannot guarantee that user information will remain private. We acknowledge that, in spite of our committed effort to protect private user information, determined individuals may still develop data-mining and other methods to uncover such information and disclose it. For this reason, the Holowiki can make no guarantee against unauthorized access to information provided in the course of participating in Holowiki activities. a83038037d2c5bacc447dab1062d0c9c687d0a3d 4 1220 2574 2572 2014-04-22T00:45:11Z Jsfisher 1 Protected "[[Holowiki - A Holography FAQ:About]]" ([Edit=Allow only administrators] (indefinite) [Move=Allow only administrators] (indefinite)) wikitext text/x-wiki Holowiki is the knowledge base wiki form for its sister operation, http:Holoforum.org/forum. The latter is a bulletin board discussion forum for holography professionals, hobbyists, and innocent by-standers. Holowiki is much of the collected wisdom and accomplishments posted on the forum along with other information collected from a variety of public sources. The administrator for Holowiki is John Fisher. 6c1eeb73f17e7a7a01910823f204f20c45354483 2576 2574 2014-04-22T01:24:40Z Jsfisher 1 wikitext text/x-wiki Holowiki is the knowledge base in wiki form for its sister operation, http:Holoforum.org/forum. The latter is a bulletin board discussion forum for holography professionals, hobbyists, and innocent by-standers. Holowiki is much of the collected wisdom and accomplishments posted on the forum along with other information collected from a variety of public sources. The administrator for Holowiki is John Fisher. d5a142ac8957f6b83c8fcb3f8640c0f7000005a8 0 501 2575 2541 2014-04-22T01:18:35Z Jsfisher 1 wikitext text/x-wiki Silver Halide is one of the most popular recording materials. The historical and available commercially available films properties are listed here: *[[Silver Film Comparison Chart]] *[[DIY Silver Halide Film]] *[[Silver Halide Processing Chemistry]] *Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''' with comments *[[Silver Halide Film vs Chemistry vs Hologram Type]] *[[Cold Water Processing]] *[[Silver Halide Sensitized Gelatin]] SHSG *[[Index Matching]] *[[Pre-Swelling]] *[[Post-Swelling]] *[[Squeegee Technique]] *[[Fringe Photos]] *[[Painting Holograms]] *[[Exposure Tests]] *[[Hardening Holograms to Fix the Color]] *[[Psuedocolor Processing]] *[[Laminating Film to Glass]] 7a1653bdbfa5599273f5d3e0da70d819ff5cdc62 2 1221 2577 2014-04-23T02:36:48Z Jsfisher 1 Created page with "JSFisher is the username for John Fisher, the adminstrator for this Holowiki site. His qualifications for having full authority over this compendium of all things holographic..." wikitext text/x-wiki JSFisher is the username for John Fisher, the adminstrator for this Holowiki site. His qualifications for having full authority over this compendium of all things holographic are minimal. In fact, he is the self-proclaimed World's Worst Holographer. You may contact him via gmail. Remarkably, holographyforum was unclaimed as a username. The prior two sentences contain all the information needed for a human to send email to JSFisher; hopefully, spam bots will still be in the dark. 66beb71c2198aa784d6de90954cf2f1dcbf2430f 0 1 2578 2566 2014-04-23T02:41:20Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:Battin 215M.JPG|right|400px|Hologram by Dave Battin]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 13c3ae81e1c08236ca2828fa25e7045ecc087fa5 2580 2578 2014-04-24T02:21:12Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:3framewiggle.gif|right|400px|Animated GIF of three views of one hologram by dannybee]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] e47fbd8fe8875c378cb62ac1a0e0e82c3174272d 2581 2580 2014-04-24T17:30:51Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:HOLO 1.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 37eee446908015332aa5c65d381ca9c00599ff58 2585 2581 2014-05-03T01:32:12Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. {{note | 02 May 2014 -- The Holography Forum is experiencing temporary technical difficulties. The site administrator has been informed | error}} You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:HOLO 1.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 36655535a73f1bab19e1b885140f43842558d0c6 2586 2585 2014-05-06T21:18:38Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. {{note | * 06 May 2014 -- Not sure what the situation is with ''www.holoforum.org/forum''. I will update the status, here, as information becomes available. * 02 May 2014 -- The Holography Forum is experiencing temporary technical difficulties. The site administrator has been informed | error}} You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:HOLO 1.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 98c865dcf2d7690c2abd5dec7809ba0cc8b4c697 2587 2586 2014-05-09T01:01:39Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holowiki.nss.rpi.edu/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holowiki.nss.rpi.edu/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holowiki.nss.rpi.edu/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. {{note | * 08 May 2014 -- Still no response from the site administrator of www.holoforum.org/forum. However, to get things back online, a copy of the forum has been installed on the wiki site. ''HOLOWIKI.NSS.RPI.EDU/forum'' is the current site for the holography forum. * 06 May 2014 -- Not sure what the situation is with ''www.holoforum.org/forum''. I will update the status, here, as information becomes available. * 02 May 2014 -- The Holography Forum is experiencing temporary technical difficulties. The site administrator has been informed }} You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:HOLO 1.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 0f605385f7086b862146ef3310f59dce3705339b 2588 2587 2014-05-10T01:24:54Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. {{note | * 09 May 2014 -- Hurray!! The original forum site has returned. Many thanks to the forum administrator for remedying the database problem. Meanwhile, the short-lived forum replica built at the holowiki site will be decommissioned now that the original has returned. * 08 May 2014 -- Still no response from the site administrator of www.holoforum.org/forum. However, to get things back online, a copy of the forum has been installed on the wiki site. ''HOLOWIKI.NSS.RPI.EDU/forum'' is the current site for the holography forum. * 06 May 2014 -- Not sure what the situation is with ''www.holoforum.org/forum''. I will update the status, here, as information becomes available. * 02 May 2014 -- The Holography Forum is experiencing temporary technical difficulties. The site administrator has been informed | reminder }} You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:HOLO 1.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] f11ea4ceb9bd77924928c0b3e645204420220edf 2590 2588 2014-05-24T15:14:16Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:HOLO 1.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. * A new ''My First...'' entry in the DCG section of the '''[[Gallery]]'''. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 9b1d36fdd486fb861d5d9ac005113d31692fad9b 2597 2590 2014-08-04T14:42:04Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 94fc3231c9985b9e92d8283104c84ef015a2afdd 6 1222 2579 2014-04-24T02:19:49Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 193 2582 1980 2014-04-25T14:09:50Z Jsfisher 1 wikitext text/x-wiki [[Image:Colink.jpg]] Colin Kaminski is an amateur holographer who in a state of extreme frustration and needing advice started the forum that has become the [http://www.holoforum.org/forum Holography Forum] and then this Wiki. He really has no other holography related accomplishments other than about 100 or so 4x5" and smaller holograms given to children. He has worked as an Assembly Language Programmer, Motorcycle Mechanic, Luthier, Theatrical Lighting Designer, Product Designer and now he is the Master Brewer at [http://www.downtownjoes.com Downtown Joe's] in Napa, CA. [http://www.designerinlight.com Colin Kaminski's Web Site] [[Image:Colinemail.gif]] 57e8f2464d494874847ec91cb7ab20eb0350990d 0 159 2583 1563 2014-04-25T20:36:45Z Jsfisher 1 wikitext text/x-wiki [[Category:DCG]] [[Category:Beginner]] [[Category:Farina]] ==Here's my two cents:== From Joe Farina: Mix dichromate, gelatin, and water using some kind of double-boiler method, and keep it under 60C. Coat plates using whatever method you prefer. Let them dry under a gentle air flow for 4 hours. Store your plates in the refrigerator (use lock & lock or some other kind of airtight container). Make as many plates as possible to enable lots of tests. Do not desiccate or do anything else to them. (By the way, use Knox gelatin from the grocery store.) Now, do tests at your lesiure. Just take your container out of the fridge, let it get up to room temperature, and take a plate out (or you can immediately take it out if you hit the surface of the gelatin hard with warm air from a hairdryer to prevent excess condensation). Expose Denisyuk style with 100mW at 532. (I would say 2.5" X 2.5" plates would be good.) Let them set in the dark for 5 minutes after exposure. Rinse under cold tap water for a minute until the yellowness goes away. Soak in room-temperature water for a minute. Soak in 91% for a minute with agitation (room-temperature). Soak in 99% for three minutes with agitation (room-temperature). Then dry with hot air. If there is milkiness, you will need to harden the gelatin more after the dark reaction. You can user fixer or a 100W light bulb 6 inches away (for varying time periods) to do this. I prefer the light bulb method. See how your plates age, and how they perform over time. Change variables to see different results (well, I don't need to tell you this, since you probably know better than I do about trial-and-error work in holography). Just use the same principles you use to get such good silver halide holograms. One last word: don't try to pre-plan things too much. Just use the simplest DCG technique possible (it is really very simple if you have blue or green light). Don't make it any more complex than it has to be. End of lecture. * With a C315M (532nm) at 100mw start with a 1 to 3 minute exposure and adjust by factors of two to find the right exposure range. ie. 45 seconds, 90 seconds, 180 seconds. f4397d7e3e179fbf96865491d840d1500c5d7da1 0 892 2584 2111 2014-04-25T21:35:30Z Jsfisher 1 /* Silver-halide */ wikitext text/x-wiki This is a collection of simple tips and techniques worth sharing. == Darkroom == == Optics == === Rotating Polarization with Mirrors === {| | [[Image:PolarizRotateWMirrors.jpg | right]] This image is self explanitory on how to rotate the polarization of the laser beam with two front surface steerable mirrors. This was taken directly from [[Media:kaveh-PhD.pdf | Kaveh's Thesis]] with his permission. |} == Silver-halide == === Defogging PFG-03 === I have successfully killed bad fogging on Slavich plates (without also killing the photosensitivity) by soaking them for exactly 60 seconds in a solution of: * 20 g Ferric EDTA * 10 g KBr * Water to make 1,000 ml This solution keeps for years. Ferric EDTA is ethylenediaminetetraacetic acid ferric sodium salt. What amazed me was that the photosensitivity of the plates did not drop noticeably afterwards without my needing to resensitise them in say 2% ascorbic acid (vitamin C) at pH ~6. ~Jeff Blythe === Defogger === adapted from the thread http://holoforum.org/forum/viewtopic.php?f=9&t=215 PBU (Phillips - Bjelkhagen Ultimate) bleach makes a good film defogger * 10 g Potassium persulfate * 10 g Sodium bisulfate (or citric acid) * 20 g Potassium bromite * 1 g Cupric bromide * 1 g Amidol (or Metol) To use it as defogging solution, pH must be raised first, otherwise the sensitizing dyes will be deactivated. (This is true at least for the PFG-03C dyes.) Diluted it 1:10 parts water, then raise the pH to 5.6 by adding drops of 10% sodium hydroxide. Soak the plates for 1 minute in the solution, then rinse and allow to dry. == DCG == ==== Effect of Overexposure ==== {| | [[Image:DCGdiffeff.jpg | 400px | right]] adapted from a post by Joe Farina, http://holoforum.org/forum/viewtopic.php?f=7&t=652 Overexposure can have a drastic effect on dichromated gelatin. Test strips early and often are well advised. The graph is from ''Lasers and Holography'' by Mehta and Rampal, 1993. It was reprinted from a paper by Chang and Leonard, "Dichromated gelatin for the fabrication of holographic optical elements," ''Applied Optics'', 1979. |} ==== Boiling holograms ==== {| | {| style="float: right;" | [[Image:bb1.jpg | 250px | Buddha before boiling]] |- | [[Image:bb2.jpg | 250px | Buddha after boiling]] |} adapted from a post by manalokos, http://holoforum.org/forum/viewtopic.php?f=7&t=138 I was frustrated with a hologram of a tiny buddha statue because it was dim and narrow-band, shifting a bit too much to the blue. I heated water until it boiled, took it out of the heat source, and then dropped the plate inside, left it there for 60 seconds, and put it into ambient temp water. I re-developed it, and I got a much more broadband and brighter result. |} 228887e7e1fa1f2e0fcd5f2b7443c959cbb1af39 0 818 2589 1629 2014-05-12T00:06:57Z Jsfisher 1 /* Additional selected DCG related publications (to 1996) */ wikitext text/x-wiki === Early researchers (to 1974) === *T. A. Shankoff, "Phase holograms in dichromated gelatin" ''Appl. Opt.'' '''7:'''2101-2105, 1968 *T A Shankoff and R K Curran "Efficient, high resolution, phase gratings", ''App Physics Letters'' 13:pp239-241, 1968 *L.H. Lin, "Hologram Formation in Hardened Dichromated Gelatin Films." il ''Ap Optics'' 8:963-6 My, 1969 *H. Kogelnik, "Coupled wave theory for thick hologram gratings" ''Bell Syst Tech J.'' '''48''':2909-2947, 1969 *R.G. Brandes and others, "Preparation of Dichromated Gelatin Films for Holography." ''Ap Optics'' 8:2346-8 N, 1969 *R.K. Curran and T.A. Shankoff, "Mechanism of Hologram Formation in Dichromated Gelatin." ''Ap Optics'' 9:1651-7 Jl, 1970 *T.P. Sosnowski and H. Kogelnik, "Ultraviolet Hologram Recording in Dichromated Gelatin." ''Ap Optics'' 9:2186-7 S, 1970 *M. Chang and N. George, "Holographic Dielectric Grating; Theory and Practice" ''Ap Optics'' '''9''':713-719, March 1970 *L.H. Lin, "Method of Characterizing Hologram-Recording Materials." ''Opt Soc Am J.'' 61:203-8 F ,1971 *Milton Chang, "Dichromated Gelatin of improved optical quality", ''App Optics'', 10&nbsp;: p2550-2551, Nov 1971 *D. Meyerhofer, "Spatial Resolution of Relief Holograms in Dichromated Gelatin." ''App Optics'' 10:416-21 F, 1971 *Gary Fillmore, Richard Tynan, "Sensitometric characteristics of hardened dichromated gelatin films" ''J of Op Soc,'' 61:pp199-202, 1971 *K S Pennington, J S Harper, "New photo technology suitable for recording phase holograms and similar information in hardened gelatin", ''App Phys Lett'' 18: pp80-84, 1971 *W. S. Colburn, "Holographic Optical Elements", ''Technical Report, contract F33615-72-C-1156'', 1973 *F. T. S. Yu. "Effect of Emulsion Thickness Variations on Wavefront Reconstruction". ''App Optics'' '''10''':1324-1328 June 1971 *D. Meyerhofer, "Phase Holograms in Dichromated Gelatin.". ''RCA R.'' 33:110-030 Mr, 1972 *D. H. Close, A. Graube, "Materials for Holographic Optical Elements", ''Technical Report AFML-TR-73-267'', Oct. 1973. *A. Graube, "Holograms recorded with red light in Dye sensitized dichromated gelatin", Optics Comm.8:251-253 *D G McCauley, "Holographic Optical Element for visual display applications", App Optics, 12: 232-241, 1973 *D.H.Close, A. Graube, "Holographic Lens For Pilot's head up display", ''Techmical report, contract# N62269-73-C-0388'', 1974 *R D Rallison, "DCG applied with a record player and broadband processed in 2 minutes" ''Hughes Aircraft'', Jan 1974 (never published, just bragged a lot) === Additional selected DCG related publications (to 1996) === *S. K. Case. "Coupled Wave Theory for Multiple Exposed Thick Holographic Gratings". ''Opt Soc Am J.'' 65: 724-9 Je, 1975 *A.Alferness, S.K. Case, "Coupling in Doubly Exposed, Thick Holographic Gratings" ''Opt Soc Am J.''65:730-9 Je 1975 *R.V. Pole and H.P. Wollenmann, "Holographic Laser Beam Deflector". ''App Optics'' 14:976-80 Ap 1975 *S. K. Case, "Multiple exposure holography in Volume Materials", ''Doctoral Dissertation'', U of Michigan, 1976 *B.J. Chang, "Post Processing of Developed Dichromated Gelatin Holograms", ''Optics Communications'', '''17''' (3): 270-271, June 1976. *T. Kubota, T. Ose, M. Sasake and K. Honda "Hologram Formation with Red Light in Methylene Blue Sensitized Dichromated Gelatin" ''Applied Optics,'' '''15'''(2):556-558, Feb. 1976. *W. S. Colburn &amp; B. J. Chang "Holographic Combiner for Head-Up Displays", ''Technical Report AFAL-TR-77-110'' , Jan 1977 *H. M. Smith, ''Holographic Recording Materials,'' Springer Verlag, 1977 *A. Graube, "Dye Sensitized dichromated gelatin for holographic optical element fabrication" Photographic Sci and Eng, 22: pp37-41, 1978 *A. Graube, "Holographic optical element materials research", ''Technical report, Air Force contract # F44620-76-C-0064,'' 1978 *S.K. Case and W.J. Dallas, "Volume Holograms Constructed from Computer Generated Masks." ''App Opt'' 17:2537-40 Ag 15, 1978 *R D Rallison, "Fabrication of a holographic scanning disc" ''Technical report to IBM'', Raleigh NC, 1979 *R D Rallison, "Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)."''SPIE Proceedings'' 212:22, 1979 *B.J. Chang and C. D. Leonard, "Dichromated Gelatin for the Fabrication of Holographic Optical Elements", ''App Opt'' 18:2407-17 Jl 15, 1979 *S.P. McGrew, "Color Control in Dichromated Gelatin Reflection Holograms", ''Proc. SPIE'' '''215''':24-31, 1980. *B.J. Chang, " Dichromated Gelatin Holograms and Their Applications". ''Opt Eng'' 19:642-8 S/O, 1980 *W.R. Graver et al, "Phase Holograms Formed by Silver Halide Sensitized Gelatin Processing" ''App Opt'' 19:1529-36 My 1, 1980 *S.K. Case et al, "Multi facet Holographic Optical Elements for Wave Front Transformations". ''App Opt'' 20:2670-5 Ag 1 1981 *Sven Sjolinder, "Dichromated Gelatin and the Mechanism of hologram formation", ''Photo Sci and Eng'', 25: pp 112-117, 1981 *D. A.Winick, "Thick Phase Holograms", Environmental Research institute of Michigan, Level, January 1981 *L. Solymar &amp; D.J. Cooke , ''Volume Holography and Volume Gratings'', Academic Press, 1981. *J. Oliva et al, "Diffuse-Object Holograms in Dichromated Gelatin." ''App Opt'' 21:2891-3 Ag 15, 1982 *H. Bartelt, S.K. Case, "High-Efficiency Hybrid Computer-Generated Holograms." ''Appl Opt'' 21:2886-90 Ag 15,1982 *R D Rallison, "Hologram Scanner Design and Fabrication in Dichromated Gelatin (DCG)." Proc SPIE, August, 1982 *R D Rallison, "Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College First International Symposium on Display Holography, July 1982 *L.D. Dickson, "Holography in the IBM 3687 Supermarket Scanner", ''IBM J. Res &amp; Devel'' 26:228-34 Mr 1982 *.J.E. Ludman, "Approximate Bandwidth and Diffraction Efficiency in Thick Holograms." ''Am J. Physis'' 50:244-6 Mr.1982 *Tung H. Jeong, ''Proceedings of the International Symposium on display holography,'' Vol I 1983 *Y.-Z Liang, "Multifocus Dichromated Gelatin Hololens". ''Appl Opt'' 22:3451-6 N 1 1983 *A. Fimia, "Noise Reduction in Holographic Images Reconstructed with Blue Light". ''Appl Opt'' 22:3318 N. 1, 1983 *J. Oliva et al, "Dichromated Gelatin Holograms Derived from Agfa 8E75 HD Plates" ''Appl Opt'' 23:196-7 Ja 15 1984 *R D Rallison, "Characteristics of Dichromated Gelatin (DCG) Scanners for Printing Applications"''Proc. SPIE''. 498: 199, 1984 *R D Rallison,"Applications of Holographic Optical Elements" Lasers and Applications,pp61-64 December 1984, *S. Calixto and R.A. Lessard, "Real-Time Holography with Undeveloped Dichromated Gelatin Films" ''Appl Opt'' 23:1989-94 Je 15, 1984 *Ryszard Gajewski "Holographic Technology for Solar Energy Concentration" ''Technical Report No. 87-1479'', 1984. *C. Solano, Lessard et al, "Red Sensitivity of Dichromated Gelatin Films".''Appl Opt'' 24:1189-92 Ap 15 1985 *J. C. Newell et al, "Holograms in Dichromated Gelatin: Real-Time Effects" ''Appl Opt'' 24:4460-6 D 15 1985 *Jose R. Margarinos &amp;Daniel J Coleman "Holographic Mirrors" ''Proc. SPIE'' '''523''':203-218, 1985. *C. Solano and R.A. Lessard, "Phase Gratings Formed by Induced Anisotropy in Dyed Gelatin Plates" ''Appl Opt'' 24:1776-9 Je 15 1985 *Richard D. Rallison, "Holographic Optical Elements (HOES) in Dichromated Gelatin (DCG)", ''Proc. SPIE'' '''523''':292-295 (1985). *S. Calixto et al "Real-Time Optical Image Processing and Polarization Holography with Dyed Gelatin". ''Appl Opt'' 24:2941-7 S 15 1985 *Tung H. Jeong, P''roceedings of the International Symposium on display holography'' Vol II 1986 *T. Kubota, "Recording of High Quality Color Holograms" ''Appl Opt'' 25:4141-5 N 15 1986 *P. Hariharan, "Silver Halide Sensitized Gelatin Holograms: Mechanism of Hologram Formation." ''Appl Opt'' 25:2040-2 Jl 1, 1986 *R. Changkakoti and S.V. Pappu, "Study on the pH Dependence of Diffraction Efficiency of Phase Holograms in Dye Sensitized Dichromated Gelatin." ''Appl Opt'' 25:798-801 Mr 1 1986 *C. Solano et al Methylene Blue Sensitized Gelatin as a Photosensitive Medium for Conventional and Polarizing Holography" ''Appl Opt'' 26:1989-97 My 15 1987 *Daniel K. Angell, "Improved diffraction efficiency of silver halide (sensitized) gelatin", ''Appl Opt'', 26:4692-4701,1987 *R D Rallison,"Holographic Scanners for Machine Vision, Printing, and Bar Code Applications." Proc. SPIE 747:pp 1987 *H K Liu, "Simplified dichromated gelatin hologram recording process", ''App Optics'', 26:372-376, 1987 *D.J. Jacobs and M. G. Marsland, "Reduction of Sensitizer Concentration Gradients in Dichromated Gelatin Films" ''J Phys E''. 20:899-901 Jl 1987 *R. D. Rallison, "Materials for Volume Phase Holographic Notch Filters" ''SBIR #A 86-68 Final Report'', U.S. Army CECOM, Ft. Monmouth, N.J. Aug.1987 *Jon D. Masso "Multilayer Thin Film Simulation of Volume Holograms" ''Proc. SPIE'' '''883''':68-72, 1988 *R D Rallison, "Cascaded Transmission Holograms for Head-Up Displays". ''Proc. SPIE'' 883: pp 1988 *N. Capolla and R.A. Lessard, "Processing of Holograms Recorded in Methylene Blue Sensitized Gelatin" ''Appl Opt'' 27:3008-12 Jl 15, 1988 *R. D. Rallison "Incoherent Multifocus Hololens design and fabrication", ''Proc. SPIE'' '''1183''':663-668 1989 *R. D. Rallison "Survey of properties of volume holographic materials", ''Proc. SPIE'' '''1051''':68-75 1989 *James M Tedesco, "Holographic laser -protective filters and eye-wear" Opt Eng 28:p609-615, 1989 *Y. Amitai et al "Holographic Elements with High Efficiency and Low Aberrations for Helmet Displays", ''Appl Opt'' '''28''':3405-3416 Aug 15 1989 *J. L. Salter and M. F. Loeffler, "Comparison of dichromated gelatin and Dupont HRF-700 photopolymer as media for holographic notch filters" ''Proc. SPIE'' '''1555''':268-278 (July 1991) *Chris Rich, David Cook, "Lippman volume holographic filters for Rayleigh Line rejection in Raman Spectroscopy", Proc. SPIE 1461:2-7, 1991 *R. D. Rallison, "Control of DCG and non silver holographic materials" ''Proc. SPIE'' '''1600''': 26-37 1991. *R D Rallison,"Polarization properties of gelatin holograms" ''Proc''''. SPIE'' 1667:pp 1992. *R D Rallison, "Using Thick DCG, 30 to 100 microns" Proc. SPIE 1914:pp 1993. *L D Dickson, R D Rallison et al, "Holographic polarization-separation elements" ''Appl Opt''. 33:5378-5385, 1994 *R. D. Rallison and S. R. Schicker, "Wavelength compensation by time reverse ray tracing", ''Proc. SPIE'' '''2404''': 217-225 1995 *Hans Dieter Tholl, "Polarization properties of volume phase gratings", ''Optical Engineering'', '''34'''(10)2879-2885 Oct 1995 *Hans I Bjelkhagen, ''Holographic Recording Materials'', SPIE publications, 1996. *R D Rallison, Steve Arnold, "Wavelength compensation at 1.064 microns using hybrid optics" Proc SPIE 2689, 1996 [[Category:Rallison]] [[Category:DCG]] 31e745586d715fb83d44f97161257f8247e63d53 6 1223 2591 2014-06-18T13:11:46Z Jsfisher 1 wikitext text/x-wiki da39a3ee5e6b4b0d3255bfef95601890afd80709 0 222 2592 1669 2014-06-27T23:12:00Z Jsfisher 1 wikitext text/x-wiki [[Image:Edwesley.jpg]] Ed Wesly Website: http://edweslystudio.com/ Ruby Pulsed Hologram - Fermilab PROFESSIONAL OBJECTIVE: To continue to share my wealth of knowledge and experience with more students in the fields of lasers, optics, holography and photography. TEACHING EXPERIENCE: Full-Time Faculty, Harrington College of Design, teaching Physics of Light (Optics), Photo-History, and College Math in the Digital Photography Department, January 2005 to present. Adjunct Assistant Professor, teaching a variety of classes in the Art and Technology and Liberal Arts Departments at the School of the Art Institute of Chicago, including the Beginning and Intermediate/Advanced Holography Studio, Optics for Artists, 3-D Hard Copy, and The Physics of Everyday Objects, January 1986 to present, with a couple of hiatuses. Instructor, Columbia College, Chicago, for the courses, "The Physics of Lasers, Holograms, and Modern Optics", "Photographic Theory/Laboratory Practice for Cinematographers", and "Imaging Optics", February 1985 to June 1997. Teacher, Cicero School, Cicero, IL, 7th and 8th grade Math Classes, September 1981 to June 1982. Director of Education for the Fine Arts Research and Holographic Center, Chicago, IL, June 1980 to May 1981. Teacher, Hardey Preparatory School, Chicago, 6th, 7th, and 8th grade Math Classes, September 1977 to June 1980. TECHNICAL EXPERIENCE: Production Holographer, CFC International, Countryside, IL, laboratory technician preparing holographic images for mass production, October 1998 to November 2004. Sales Engineer, BEA electro-optics, Des Plaines, IL, manufacturer's representative for a variety of electro-optical companies, June 1997 to October 1998. Research Associate at Lake Forest College, Lake Forest, IL, supported by a grant from a manufacturer of medical equipment to test the feasibility of replacing conventional optics in some of their equipment with Holographic Optical Elements, October 1987 to February 1993. Holographic Engineer for Northwestern University, Evanston, IL, researching holographic endoscopes using Ruby laser light piped through fiber optics, May 1986 to May 1987. Holographic Engineer for Holicon Corporation, Evanston, IL, setting up a studio to record holographic portraits using a Ruby laser, May 1986 to May 1987. Holographer for the 15 foot Bubble Chamber at Fermilab, Batavia, IL. Part of a team using a Ruby laser to make holograms of atomic particle tracks, March 1985 to April 1986. Optical Engineer for Magnaflux Corporation, Chicago, IL. Designed and built an 8 by 8 foot isolation table equipped with an Argon laser for real time interferometry of large objects, October 1983 to September 1984. EDUCATIONAL BACKGROUND: University of Illinois at Urbana, Bachelor's of Science Degree in the Teaching of Mathematics, January 1976. PROFESSIONAL ORGANIZATIONS: Member of the Optical Society of America, (OSA), and the Society of Photo-Instrumentation Engineers (SPIE). Councillor for Chicago Chapter of SPIE/Optical Society of Chicago Featured Speaker at the June, 1997 meeting of the Optical Society of Chicago. PUBLICATIONS TEXTBOOKS (self-published): INSTRUCTION MANUAL FOR THE HOLOGRAPHY STUDIO AT SAIC, September 1995 OPTICS FOR ARTISTS, September 1995 (e-version on-line Fall 2003) PHOTOGRAPHIC THEORY/LABORATORY PRACTICE For Cinematographers, September 1995 IMAGING OPTICS, February 1996 VIDEOS: "Ruby Laser Guts", 1996, and "Gaseous Lasers", 1996 SELECTED ARTICLES: "Inside-Out Engineering: Characterizing the Holographic Stereogram Printer at The School of the Art Institute of Chicago", Proceedings of the SPIE, 1997. "A Toast to Nick Phillips", Leonardo, Volume X, Number 3, 1992. "A Proposal for a National Space Monument", Proceedings of the SPIE, Vol. 1600, 1991. "Holography of Particle Tracks in the Fermilab 15-Foot Bubble Chamber," with W. Smart et al., Nuclear Instruments and Methods in Physics Research A297, 1990, p.364-389. "Teaching Holography in an Art School Environment," Proceedings of the SPIE, Vol. 1396, 1990. "Progress in True Color Holography", with T. Jeong, Proceedings of the SPIE, Vol. 1211, 1990. "Recycling Holographic Plates", Proceedings of the Third International Symposium on Display Holography, Lake Forest College, 1988. "Exploring Personal Holography", Darkroom and Creative Camera Techniques, Nov/Dec. 1986. "Seven Single Beam Projects", Proceedings of the Second International Symposium on Display Holography, Lake Forest College, 1985. Technical Editor for holosphere, the Advocate of Holographic Art, Science, and Technology, 1985 to 1991. REFERENCES: Dr. Tung Jeong, emeritus, Lake Forest College, Lake Forest, IL (Tjeong@aol.com) Dr. Hans Bjelkhagen, DeMontfort University, Leicester, England (Hansholo@aol.com) Dr. Manfred Stelter, PTI, Oak Creek, WI (pti@execpc.com) Dr. Gerald Cohn, Cyber-Tech, Evanston, IL (cybertek@megsinet.net) Dr. Elizabeth Wright, School of the Art Institute of Chicago, Chicago, IL (ewright@artic.edu) Dr. Pan Papacosta, Columbia College, Chicago, IL EXHIBITIONS: GROUP SHOWS Untitled, Richard Hunt Art Center, Benton Harbor Michigan, November 1996. Candy for the Eyes, Mind and Sol Gallery, Chicago, IL, September 1995. Unknown Chicago, Gallery 312, Chicago, IL, July 1995. The Fourth International Exhibition of Display Holography, Lake Forest College, July 1991. Matter Over Mind Sculpture Conference, Fermilab, Batavia, IL, May 1991. Diorama Wonderama, Gallery 836, Chicago, IL, November 1990. L.A.S.E.R. Members Show, Holos Gallery, San Francisco, CA, Summer 1990. New Media, New Directions, Northern Indiana Arts Association, Munster, IN, August, 1990. International Congress on Art in Holography, May - July 1990. The One-Liner Show, Gallery F-XU, Chicago, IL, February 1990. Visual Perceptions: Color, Light and Space, Gallery of Design of the Merchandise Mart, Chicago, IL, February 1989. The Third International Exhibition of Display Holography, Lake Forest College, July 1988. Visions in Light, Museum of Holography, Summer 1988. Images in Time and Space, Montreal, Canada, May 1987 to June 1989. The Holographic Instant: Pulse Laser Holograms, at the Museum of Holography, New York, May to October 1987. A.I.R. Waves at the Museum of Holography, New York, January to May 1987. 2 X 2 Show at the School of the Art Institute of Chicago, May 1986. Holography Group Show at the Limelight, Chicago, February 1986. Holography Exhibition at the School of the Art Institute of Chicago, November 1985. The Second International Exhibition of Display Holography, Lake Forest College, July 1985. New Light, Chicago Public Library Cultural Center, July 1984. The Connie Show, W.P.A. Gallery, Chicago, IL, April 1984. Stare Magazine Fifth Anniversary Show, at Word City, Chicago, June 1982. Post-Mortem Moderne, at the House o' Beauty, Chicago, IL, July 1980. First Contact, Chicago, IL, February, 1979. Illinois Photographers' Lottery, De Kalb, IL, May, 1978. EXHIBITIONS: ONE MAN SHOWS Down in the Basement, Artigliography, Indianapolis, IN, September - October, 1990. Doodles, Atlanta Gallery of Holography, Atlanta, GA, April 1990 Recent Pulsed Stuff and Other Delights at Benny's CASINO, Chicago IL, August 1986. AWARDS: Artist in Residence Direct Grant, from the Museum of Holography, New York, October 1984. Participant in the International Congress on Art in Holography, St. Mary's College, South Bend, IN, July 1990. COLLECTIONS: Global Images, Vancouver, British Columbia, Canada. Museum of Holography Collection, MIT Museum, Cambridge, MS. Dimensional Imaging Consultants, Niles, MI. Hans Bjelkhagen, Leicester, England 8872c6cf7b43a593110be6c1de8a65e56604908f 2593 2592 2014-06-27T23:12:23Z Jsfisher 1 wikitext text/x-wiki [[Image:Edwesley.jpg]] Ed Wesly Website: http://edweslystudio.com/ Ruby Pulsed Hologram - Fermilab PROFESSIONAL OBJECTIVE: To continue to share my wealth of knowledge and experience with more students in the fields of lasers, optics, holography and photography. TEACHING EXPERIENCE: Full-Time Faculty, Harrington College of Design, teaching Physics of Light (Optics), Photo-History, and College Math in the Digital Photography Department, January 2005 to present. Adjunct Assistant Professor, teaching a variety of classes in the Art and Technology and Liberal Arts Departments at the School of the Art Institute of Chicago, including the Beginning and Intermediate/Advanced Holography Studio, Optics for Artists, 3-D Hard Copy, and The Physics of Everyday Objects, January 1986 to present, with a couple of hiatuses. Instructor, Columbia College, Chicago, for the courses, "The Physics of Lasers, Holograms, and Modern Optics", "Photographic Theory/Laboratory Practice for Cinematographers", and "Imaging Optics", February 1985 to June 1997. Teacher, Cicero School, Cicero, IL, 7th and 8th grade Math Classes, September 1981 to June 1982. Director of Education for the Fine Arts Research and Holographic Center, Chicago, IL, June 1980 to May 1981. Teacher, Hardey Preparatory School, Chicago, 6th, 7th, and 8th grade Math Classes, September 1977 to June 1980. TECHNICAL EXPERIENCE: Production Holographer, CFC International, Countryside, IL, laboratory technician preparing holographic images for mass production, October 1998 to November 2004. Sales Engineer, BEA electro-optics, Des Plaines, IL, manufacturer's representative for a variety of electro-optical companies, June 1997 to October 1998. Research Associate at Lake Forest College, Lake Forest, IL, supported by a grant from a manufacturer of medical equipment to test the feasibility of replacing conventional optics in some of their equipment with Holographic Optical Elements, October 1987 to February 1993. Holographic Engineer for Northwestern University, Evanston, IL, researching holographic endoscopes using Ruby laser light piped through fiber optics, May 1986 to May 1987. Holographic Engineer for Holicon Corporation, Evanston, IL, setting up a studio to record holographic portraits using a Ruby laser, May 1986 to May 1987. Holographer for the 15 foot Bubble Chamber at Fermilab, Batavia, IL. Part of a team using a Ruby laser to make holograms of atomic particle tracks, March 1985 to April 1986. Optical Engineer for Magnaflux Corporation, Chicago, IL. Designed and built an 8 by 8 foot isolation table equipped with an Argon laser for real time interferometry of large objects, October 1983 to September 1984. EDUCATIONAL BACKGROUND: University of Illinois at Urbana, Bachelor's of Science Degree in the Teaching of Mathematics, January 1976. PROFESSIONAL ORGANIZATIONS: Member of the Optical Society of America, (OSA), and the Society of Photo-Instrumentation Engineers (SPIE). Councillor for Chicago Chapter of SPIE/Optical Society of Chicago Featured Speaker at the June, 1997 meeting of the Optical Society of Chicago. PUBLICATIONS TEXTBOOKS (self-published): INSTRUCTION MANUAL FOR THE HOLOGRAPHY STUDIO AT SAIC, September 1995 OPTICS FOR ARTISTS, September 1995 (e-version on-line Fall 2003) PHOTOGRAPHIC THEORY/LABORATORY PRACTICE For Cinematographers, September 1995 IMAGING OPTICS, February 1996 VIDEOS: "Ruby Laser Guts", 1996, and "Gaseous Lasers", 1996 SELECTED ARTICLES: "Inside-Out Engineering: Characterizing the Holographic Stereogram Printer at The School of the Art Institute of Chicago", Proceedings of the SPIE, 1997. "A Toast to Nick Phillips", Leonardo, Volume X, Number 3, 1992. "A Proposal for a National Space Monument", Proceedings of the SPIE, Vol. 1600, 1991. "Holography of Particle Tracks in the Fermilab 15-Foot Bubble Chamber," with W. Smart et al., Nuclear Instruments and Methods in Physics Research A297, 1990, p.364-389. "Teaching Holography in an Art School Environment," Proceedings of the SPIE, Vol. 1396, 1990. "Progress in True Color Holography", with T. Jeong, Proceedings of the SPIE, Vol. 1211, 1990. "Recycling Holographic Plates", Proceedings of the Third International Symposium on Display Holography, Lake Forest College, 1988. "Exploring Personal Holography", Darkroom and Creative Camera Techniques, Nov/Dec. 1986. "Seven Single Beam Projects", Proceedings of the Second International Symposium on Display Holography, Lake Forest College, 1985. Technical Editor for holosphere, the Advocate of Holographic Art, Science, and Technology, 1985 to 1991. REFERENCES: Dr. Tung Jeong, emeritus, Lake Forest College, Lake Forest, IL (Tjeong@aol.com) Dr. Hans Bjelkhagen, DeMontfort University, Leicester, England (Hansholo@aol.com) Dr. Manfred Stelter, PTI, Oak Creek, WI (pti@execpc.com) Dr. Gerald Cohn, Cyber-Tech, Evanston, IL (cybertek@megsinet.net) Dr. Elizabeth Wright, School of the Art Institute of Chicago, Chicago, IL (ewright@artic.edu) Dr. Pan Papacosta, Columbia College, Chicago, IL EXHIBITIONS: GROUP SHOWS Untitled, Richard Hunt Art Center, Benton Harbor Michigan, November 1996. Candy for the Eyes, Mind and Sol Gallery, Chicago, IL, September 1995. Unknown Chicago, Gallery 312, Chicago, IL, July 1995. The Fourth International Exhibition of Display Holography, Lake Forest College, July 1991. Matter Over Mind Sculpture Conference, Fermilab, Batavia, IL, May 1991. Diorama Wonderama, Gallery 836, Chicago, IL, November 1990. L.A.S.E.R. Members Show, Holos Gallery, San Francisco, CA, Summer 1990. New Media, New Directions, Northern Indiana Arts Association, Munster, IN, August, 1990. International Congress on Art in Holography, May - July 1990. The One-Liner Show, Gallery F-XU, Chicago, IL, February 1990. Visual Perceptions: Color, Light and Space, Gallery of Design of the Merchandise Mart, Chicago, IL, February 1989. The Third International Exhibition of Display Holography, Lake Forest College, July 1988. Visions in Light, Museum of Holography, Summer 1988. Images in Time and Space, Montreal, Canada, May 1987 to June 1989. The Holographic Instant: Pulse Laser Holograms, at the Museum of Holography, New York, May to October 1987. A.I.R. Waves at the Museum of Holography, New York, January to May 1987. 2 X 2 Show at the School of the Art Institute of Chicago, May 1986. Holography Group Show at the Limelight, Chicago, February 1986. Holography Exhibition at the School of the Art Institute of Chicago, November 1985. The Second International Exhibition of Display Holography, Lake Forest College, July 1985. New Light, Chicago Public Library Cultural Center, July 1984. The Connie Show, W.P.A. Gallery, Chicago, IL, April 1984. Stare Magazine Fifth Anniversary Show, at Word City, Chicago, June 1982. Post-Mortem Moderne, at the House o' Beauty, Chicago, IL, July 1980. First Contact, Chicago, IL, February, 1979. Illinois Photographers' Lottery, De Kalb, IL, May, 1978. EXHIBITIONS: ONE MAN SHOWS Down in the Basement, Artigliography, Indianapolis, IN, September - October, 1990. Doodles, Atlanta Gallery of Holography, Atlanta, GA, April 1990 Recent Pulsed Stuff and Other Delights at Benny's CASINO, Chicago IL, August 1986. AWARDS: Artist in Residence Direct Grant, from the Museum of Holography, New York, October 1984. Participant in the International Congress on Art in Holography, St. Mary's College, South Bend, IN, July 1990. COLLECTIONS: Global Images, Vancouver, British Columbia, Canada. Museum of Holography Collection, MIT Museum, Cambridge, MS. Dimensional Imaging Consultants, Niles, MI. Hans Bjelkhagen, Leicester, England ff07943571904f3461bb7cec338f196ec08f604b 0 489 2594 2563 2014-07-21T18:30:43Z Jsfisher 1 /* Heading3 */ wikitext text/x-wiki <DirList>docs</dirlist> http://abc.def.com/asdf Text <html5media height="180" width="320">File:Holograms made with albumen emulsion.mp4</html5media> <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} [[Sandbox / Subsandbox]] This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== [[User:Jsfisher|/jsfisher]] ([[User talk:Jsfisher|talk]]) 23:19, 25 June 2013 (EDT) ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y} scriptscriptstyle + 1</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> b8e0bdda598c3c6fd764caa0f566c0deef639aa2 2595 2594 2014-07-21T18:31:38Z Jsfisher 1 /* Heading3 */ wikitext text/x-wiki <DirList>docs</dirlist> http://abc.def.com/asdf Text <html5media height="180" width="320">File:Holograms made with albumen emulsion.mp4</html5media> <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} [[Sandbox / Subsandbox]] This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== [[User:Jsfisher|/jsfisher]] ([[User talk:Jsfisher|talk]]) 23:19, 25 June 2013 (EDT) ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y} scriptscriptstyle</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> f13e8f56ac3ae2a7fd2a97d9765a67beae39b9d7 2596 2595 2014-07-21T18:45:20Z Jsfisher 1 /* Heading3 */ wikitext text/x-wiki <DirList>docs</dirlist> http://abc.def.com/asdf Text <html5media height="180" width="320">File:Holograms made with albumen emulsion.mp4</html5media> <br>[http://abc.def.com/asdf Text] <br>[[http://abc.def.com/asdf Text]] <br>[[[http://abc.def.com/asdf Text]]] {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} [[Sandbox / Subsandbox]] This is what I have to say on this.<ref>sadf</ref> <references /> blah '''Bold text''' ''Italic text'' ===Heading=== ===Heading2=== ====Heading2a==== [[User:Jsfisher|/jsfisher]] ([[User talk:Jsfisher|talk]]) 23:19, 25 June 2013 (EDT) ===Heading3=== <math>z=x+y</math> <math>\displaystyle \frac{x}{y} displaystyle</math> <math>\textstyle \frac{x}{y} textstyle</math> <math>\scriptstyle \frac{x}{y} scriptstyle</math> <math>\scriptscriptstyle \frac{x}{y+1} scriptscriptstyle</math> ==Gallery== <gallery> File:Citric.jpg | Not fred.JPG File:Bulbgraph.png | Miscellaneous caption for bulb-graph png file. File:AStephens.jpg|Caption1 File:CIMG8817.JPG|Caption2 </gallery> d601a805e4668ff7f4ae4ac486f4a36094b1e3e7 0 820 2598 2562 2014-08-04T19:12:06Z Jsfisher 1 /* Overview of the Process */ wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right|Hologram by John Fisher]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques, John Fisher. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == {{note | Chemical safety is always important. In DCG-based holography, the gelatin and water used are completely safe; isopropyl alcohol and dichromates are not. Alcohol is highly flammable, especially at the higher concentrations used in drying a hologram; dichromate is a strong skin irritant and a known carcinogen. Treat them both with the respect they deserve. | gotcha }} Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. They are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if the hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. A common method to seal the hologram is to epoxy a second glass plate to the back of the hologram plate, thereby protecting it from moisture. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> Bloom (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html [[Category:DCG]] [[Category:Beginner]] 722776827c37442c505c0392c71f1ac6fc2f628f 2617 2598 2014-11-11T00:25:22Z Jsfisher 1 /* Gelatin */ wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right|Hologram by John Fisher]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image on the right was created by a newcomer to DCG techniques, John Fisher. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == {{note | Chemical safety is always important. In DCG-based holography, the gelatin and water used are completely safe; isopropyl alcohol and dichromates are not. Alcohol is highly flammable, especially at the higher concentrations used in drying a hologram; dichromate is a strong skin irritant and a known carcinogen. Treat them both with the respect they deserve. | gotcha }} Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. They are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if the hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. A common method to seal the hologram is to epoxy a second glass plate to the back of the hologram plate, thereby protecting it from moisture. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> [[Bloom value|Bloom]] (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the sample a distance of 4 mm. The more rigid the sample the higher the [[Bloom value|bloom]]. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html [[Category:DCG]] [[Category:Beginner]] 19d792785006b3a30cdd2ff3dd6d98c495321a5f 0 441 2599 1033 2014-08-31T21:25:56Z Jsfisher 1 wikitext text/x-wiki There are many published ways to coat a surface with a Meyer bar but most describe coating just a small area on the surface. Here is describe two methods for coating entire surfaces beneficial for holographic emulsion coating. ===Method 1=== This method does the best job that I have found and is depicted in the diagram below. *Take a glass size and determine what size plates you wish to coat. *Clean and sub the entire glass sheet so that it is ready to coat. In the drawing below we are doing 4 - 4inch by 5inch plates. *Make the full size glass 2 inches larger in width(1 inch on each side) and 4 inches larger in length (3 inches at top and 1 inch at bottom). *Score the glass with a glass cutter as shown but do not break any of the scores. This needs to be done on a very flat, clean and rigid surface. *Now clean the scored side from all glass chips. A wet paper towel will do nicely. TURN THE PLATE OVER. It is recommended to perform the following procedure in 80F to 90F ambient temperature or heat the glass and rod with a warm air blower (hair dryer) until warm to the touch. Also, the surface should be level in both directions. *Place the Meyer bar (ROD) at the top of the pre-scored plate. *Pour a puddle of heated emulsion across the top as shown and immediately draw the Meyer bar down the length of the plate with an even pressure and speed. You will notice the puddle stay in front of the bar and continue util you are off the bottom of the plate. *Wait until the emulsion is dry (this can be tested at any four of the discard ends). *Take a razor blade and score (cut) the emulsion down each of the scores (the scores are still on the bottom and you are cutting the emulsion on the top). *TURN THE PLATE OVER and break the scores as you would with any scored glass keeping care to not let the emulsion surface touch anything. This becomes easy with practice by keeping the end your are breaking in you hand and keeping the fixed end remain on the glass cutter knob (see [[Glass Cutter|Glass Cutting]]). Break all the longest lenghts first (top, bottom, two sides then the plates). This gives very even and uniform coatings for each glass. [[Image:PreScoredCoatAtOnce2.JPG]] ===Method 2=== In the next technique, which can be modified for more plates, we will coat 4 - 4inch by 5inch plates. *Take the 4 cleaned glass plates and place them in a rectanglur fashion such that the rectangle is 8 inches across and 10inches down on a level surface. *Now take two additional cleaned 4x5 plates (puddle plates) and lay then such that they are 10 inches across at the top of the rectangle. They will overhang the rectangle 1 inch on each side. *Now use thin clear gift tape (Scotch brand works well) to tape aound the rectangle of plates (not the top two, they will be used to pour the puddle onto) and where each plate meet another plate. Each of the four plates will have tape around all four of their sides. Make sure the tape is flattened nicely to the plate with your finger. Again use the same temperature restraints as described above (ambient or blow heater). *Place the Meyer bar at the top of the puddle plates. *Pour the heated emulsion across the center of the top two puddle plates and immediately draw the Meyer bar down the plates and off the end of the plate as described above. *Let the plates set for only one hour, then remove the tape. Allow the plates to continue to dry lying horizontally. This too yields very consistant results. This method uses the tape for some of the emulsion thickness (the Meyer bar is off the glass by the thickness of tape) so the Meyer bar should be finer the in the above proceedure. Notes: *Plate, emulsion and Meyer bar temperatures affect coating thickness to a small extent but if the temperature is too low on any of these, gelation may occure and quality compromised. *Meyer bars come in different gauges which is the thickness of the wire that is wound. Usually a #40 is .04", a #25 is a .025 inch etc.. I have found a #25 to #40 works very well in either case with the #40 producing thicker emulsion. *Meyer bars should be soaked immediately in warm water to keep the gelatin from hardening on the bar, then washed with hot water and dried. Meyer Bar Selection - [http://www.rdspecialties.com/techinfo.html] 6e548cb32ceed79dc37ae8b27faa6b2feb7e1d1c 2600 2599 2014-08-31T21:26:46Z Jsfisher 1 Jsfisher moved page [[Myer Bar Coating]] to [[Meyer Bar Coating]]: correct misspelling wikitext text/x-wiki There are many published ways to coat a surface with a Meyer bar but most describe coating just a small area on the surface. Here is describe two methods for coating entire surfaces beneficial for holographic emulsion coating. ===Method 1=== This method does the best job that I have found and is depicted in the diagram below. *Take a glass size and determine what size plates you wish to coat. *Clean and sub the entire glass sheet so that it is ready to coat. In the drawing below we are doing 4 - 4inch by 5inch plates. *Make the full size glass 2 inches larger in width(1 inch on each side) and 4 inches larger in length (3 inches at top and 1 inch at bottom). *Score the glass with a glass cutter as shown but do not break any of the scores. This needs to be done on a very flat, clean and rigid surface. *Now clean the scored side from all glass chips. A wet paper towel will do nicely. TURN THE PLATE OVER. It is recommended to perform the following procedure in 80F to 90F ambient temperature or heat the glass and rod with a warm air blower (hair dryer) until warm to the touch. Also, the surface should be level in both directions. *Place the Meyer bar (ROD) at the top of the pre-scored plate. *Pour a puddle of heated emulsion across the top as shown and immediately draw the Meyer bar down the length of the plate with an even pressure and speed. You will notice the puddle stay in front of the bar and continue util you are off the bottom of the plate. *Wait until the emulsion is dry (this can be tested at any four of the discard ends). *Take a razor blade and score (cut) the emulsion down each of the scores (the scores are still on the bottom and you are cutting the emulsion on the top). *TURN THE PLATE OVER and break the scores as you would with any scored glass keeping care to not let the emulsion surface touch anything. This becomes easy with practice by keeping the end your are breaking in you hand and keeping the fixed end remain on the glass cutter knob (see [[Glass Cutter|Glass Cutting]]). Break all the longest lenghts first (top, bottom, two sides then the plates). This gives very even and uniform coatings for each glass. [[Image:PreScoredCoatAtOnce2.JPG]] ===Method 2=== In the next technique, which can be modified for more plates, we will coat 4 - 4inch by 5inch plates. *Take the 4 cleaned glass plates and place them in a rectanglur fashion such that the rectangle is 8 inches across and 10inches down on a level surface. *Now take two additional cleaned 4x5 plates (puddle plates) and lay then such that they are 10 inches across at the top of the rectangle. They will overhang the rectangle 1 inch on each side. *Now use thin clear gift tape (Scotch brand works well) to tape aound the rectangle of plates (not the top two, they will be used to pour the puddle onto) and where each plate meet another plate. Each of the four plates will have tape around all four of their sides. Make sure the tape is flattened nicely to the plate with your finger. Again use the same temperature restraints as described above (ambient or blow heater). *Place the Meyer bar at the top of the puddle plates. *Pour the heated emulsion across the center of the top two puddle plates and immediately draw the Meyer bar down the plates and off the end of the plate as described above. *Let the plates set for only one hour, then remove the tape. Allow the plates to continue to dry lying horizontally. This too yields very consistant results. This method uses the tape for some of the emulsion thickness (the Meyer bar is off the glass by the thickness of tape) so the Meyer bar should be finer the in the above proceedure. Notes: *Plate, emulsion and Meyer bar temperatures affect coating thickness to a small extent but if the temperature is too low on any of these, gelation may occure and quality compromised. *Meyer bars come in different gauges which is the thickness of the wire that is wound. Usually a #40 is .04", a #25 is a .025 inch etc.. I have found a #25 to #40 works very well in either case with the #40 producing thicker emulsion. *Meyer bars should be soaked immediately in warm water to keep the gelatin from hardening on the bar, then washed with hot water and dried. Meyer Bar Selection - [http://www.rdspecialties.com/techinfo.html] 6e548cb32ceed79dc37ae8b27faa6b2feb7e1d1c 0 1224 2601 2014-08-31T21:26:46Z Jsfisher 1 Jsfisher moved page [[Myer Bar Coating]] to [[Meyer Bar Coating]]: correct misspelling wikitext text/x-wiki #REDIRECT [[Meyer Bar Coating]] bb5c756a1693e6a5765778883de04f6ad0fd4c7c 1 537 2602 2082 2014-08-31T21:26:46Z Jsfisher 1 Jsfisher moved page [[Talk:Myer Bar Coating]] to [[Talk:Meyer Bar Coating]]: correct misspelling wikitext text/x-wiki Colin, I don't know how to delete and uploaded file. So I had to re-upload this one and named it "PreScoredCoatAtOnce2.JPG". Could you delete the original named "PreScoredCoatAtOnce.JPG" and explain how to delete an uploaded file. I do not want to waste space on the server. John P. ---- Hi John, if you have the image showing, click on the image. There is a button for deleting it. I don't really know why we can save a new image to an old name, it is not a reported bug with this version. It likely has to do with the security settings... BTW, nice work! I deleted it... 8fd0ecdfa8831496503b7b7dec89087278d16294 1 1225 2603 2014-08-31T21:26:46Z Jsfisher 1 Jsfisher moved page [[Talk:Myer Bar Coating]] to [[Talk:Meyer Bar Coating]]: correct misspelling wikitext text/x-wiki #REDIRECT [[Talk:Meyer Bar Coating]] a5dc234d4ea4b1aaa9f9426158accbd54d819eda 0 192 2604 232 2014-08-31T21:28:03Z Jsfisher 1 wikitext text/x-wiki Coating a plate with gelatin of even thickness is a demanding task. It is quite important that the coating be of a uniform thickness. There are many methods for coating a plate listed below: [[Veil Coating (with Spin or Lean)]] [[Meyer Bar Coating]] [[Spin Coating]] [[Mold Coating]] [[Coating Machines]] [[Prepping Glass]] for coating. 9463c3d95402afb35fa268fe8465fc84b4255480 0 1226 2605 2014-11-10T03:26:48Z Jsfisher 1 Created page with "The Bloom value or Bloom strength of gelatin is a measure of its hardness. For photographic and holographic purposes, a Bloom value in the range of 200-300 is common. Anythi..." wikitext text/x-wiki The Bloom value or Bloom strength of gelatin is a measure of its hardness. For photographic and holographic purposes, a Bloom value in the range of 200-300 is common. Anything less than 200 tends to be too soft, and over 300, too hard. Most amateur holographers in the US use Knox brand gelatin (available at most grocery store) with good results. The following table gives the Bloom value for some readily available gelatins. {| class="wikitable" |- ! Product !! Bloom |- | Great Lakes (bovine) || 225 |- | Great Lakes (porcine)|| ? |- | Knox || 225 |} e33a22aa2dadd4896b024ce02d78788cb2796652 2606 2605 2014-11-10T03:35:03Z Jsfisher 1 wikitext text/x-wiki The Bloom value or Bloom strength of gelatin is a measure of its hardness. For photographic and holographic purposes, a Bloom value in the range of 200-300 is common. Anything less than 200 tends to be too soft, and over 300, too hard. Most amateur holographers in the US use Knox brand gelatin (available at most grocery store) with good results. The following table gives the Bloom value for some readily available gelatins. {| class="wikitable" |- ! Product !! Bloom |- | Great Lakes (bovine) || 225 seems to be the most commonly sold. |- | Great Lakes (porcine)|| ? |- | Knox || 225 - 235 |} 0971cf2114995801fe1d3bbc803de89d049e37f6 2607 2606 2014-11-10T03:48:51Z Jsfisher 1 wikitext text/x-wiki The Bloom value or Bloom strength of gelatin is a measure of its hardness. For photographic and holographic purposes, a Bloom value in the range of 200-300 is common. Anything less than 200 tends to be too soft, and over 300, too hard. Most amateur holographers in the US use Knox brand gelatin (available at most grocery store) with good results. The following table gives the Bloom value for some readily available gelatins. {| class="wikitable" |- ! Product !! Bloom |- | Great Lakes (bovine) || 225 |- | Great Lakes (porcine)|| 225 |- | Knox || 225 - 235 |} 708eade62ed1ea893005ebf45d342dfb4f25e00e 2608 2607 2014-11-10T04:02:49Z Jsfisher 1 wikitext text/x-wiki The bloom value or bloom strength of gelatin is a measure of its hardness. For photographic and holographic purposes, a bloom value in the range of 200-300 is common. Anything less than 200 tends to be too soft, and over 300, too hard. Many holographers in the US start with Knox brand gelatin (available at most grocery store) and get good results. The following table summarizes the bloom value for some readily available gelatins. {| class="wikitable" |- ! Product !! Bloom |- | Great Lakes (bovine) || 225 |- | Great Lakes (porcine)|| 225 |- | Knox || 225 - 235 |} Consumer-grade gelatin can vary from lot to lot. The 1-oz. box of Knox gelatin is handy for the random experiment, and it is readily available, but it may not have the consistency from box to box needed for controlled results. Moreover, small quantity purchases get expensive. The 1-oz. box may case around $3.00 US, while a full pound of either Knox or Great Lakes gelatin is less than $20.00 US. Any good baking supply shop should carry the bulk sizes at reasonable prices. a0c4aceccd838feb77de6c017dd37fec14ef0436 2613 2608 2014-11-11T00:11:58Z Jsfisher 1 wikitext text/x-wiki The bloom value or bloom strength of gelatin is a measure of its hardness. For photographic and holographic purposes, a bloom value in the range of 200-300 is common. Anything less than 200 tends to be too soft, and over 300, too hard. Many holographers in the US start with Knox brand gelatin (available at most grocery store) and get good results. The following table summarizes the bloom value for some readily available gelatins. {| class="wikitable" |- ! Product !! Bloom |- | Great Lakes (bovine) || 225 |- | Great Lakes (porcine)|| 225 |- | Knox || 225 - 235 |} Consumer-grade gelatin can vary from lot to lot. The 1-oz. box of Knox gelatin is handy for the random experiment, and it is readily available, but it may not have the consistency from box to box needed for controlled results. Moreover, small quantity purchases get expensive. The 1-oz. box may case around $3.00 US, while a full pound of either Knox or Great Lakes gelatin is less than $20.00 US over the counter. Any good baking supply shop should carry the bulk sizes at reasonable prices. <gallery> File:81Qk0XqN3JL._SL1500_.jpg File:91VwSwbY+GL._SL1500_.jpg File:91IvIbLz-DL._SL1500_.jpg </gallery> 9237354ead69cd99e9fed7094efc378f70e07cfc 6 1227 2609 2014-11-11T00:10:20Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1228 2610 2014-11-11T00:10:22Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1229 2611 2014-11-11T00:10:23Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1230 2612 2014-11-11T00:10:25Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 426 2614 1003 2014-11-11T00:19:37Z Jsfisher 1 /* STOCK SOLUTIONS for mixing: */ wikitext text/x-wiki == A simple improvement for MBDCG == The original formula for MBDCG as invented by Jeff Blyth can be found on this page: [http://http://cabd0.tripod.com/holograms/id4.html] This procedure works really well, except that in cold environments often the Methylene blue crystallizes out before the holographic plate can be used. This is likely due to the fact that Methylene Blue (MB) will not stay in a solution with Potassium Chromate when the PH is below 8. In the original formula the PH is prevented from being too high by the addition of Acetic Acid. If the plate is left to dry in a cold environment, the Acetic Acid evaporates more slowly than the water in the plate and the PH drops below this value. A more stable plate can be made with the following procedure: ===STOCK SOLUTIONS for mixing:=== * TMG: 25ml TMG + 75ml DeIonized water (1,1,3,3-tetramethylguanidine). (Be careful because TMG is a very strong alkali. Use gloves, a protective breathing mask with Carbon Filter and eye protection. Or better, use a fume cupboard.) * Potassium Chromate: 4g in 100ml DeIonized water. * Methylene Blue: 4g in 1L DeIonized water. * Boric Acid: 100g crystals in a bottle. * Gelatin: Almost any gelatin with [[Bloom value|bloom strength]] of around 220 will do here. Best results are with Bovine Alkaline gelatin, but I have had good results with pig skin gelatin from the supermarket. ===HOW TO MIX THE STOCK MBDCG SOLUTION:=== # 100ml DeIonized water. Heated to 45C. # Add 12g gelatin. # Stir until all gelatin is dissolved completely. # Optionally, the solution can now be filtered through a fine coffee filter. # Add 0.77g of Boric Acid. Crystals until all are dissolved. # Now turn on your green safe light. Add 1ml of Potassium Chromate (4% solution) # Add 4.8ml of TMG (25% solution in DI water) # Check PH of the solution. If too high, add small amount of Boric Acid and check PH again. If too low, add a drop of TMG (25% in DI water) and check PH again. The optiumum PH is between 9 and 10. Use an electronic PH meter. They cost about 40 USD. # Add 6ml of MB (0.4% in DI water). ===A SIMPLE WAY TO COAT YOUR PLATES WITH AN EXTREMELY FLAT COATING IS AS FOLLOWS (MOLD COATING):=== # Clean two glass plates with normal dish washing detergent (for hand wash). # Clean both plates with Glassex (Windex in USA), or other Ammonia based window cleaner. # Treat one glass plate with Rain-X to make it water repellent. # Stick Scotch tape to two opposite sides on the other glass plate. # Heat both glass plates with a hair drier. # Put a small amount of stock MBDCG on the Rain-X treated glass plate and gently lower the other plate (the one with the Scotch Tape on the two edges) on top of it. # Allow this sandwich to rest for about two hours. # After two hours the plates can be separated by holding them vertically and gently wedging a sharp knife in between them. # If all went well, the glass plate that was not treated with Rain-X will now have a perfectly flat coating left on it. Leave this plate to dry for a few hours. After that it is ready to by cut to smaller pieces and to be used. ===OTHER WAYS TO COAT:=== * A Coating Rod can be used (Meyer Bar). This requires some practice. Both the plate and the coating rod need to be heated. It is essential that the coating rod is drawn over the plate at a very constant speed. * The Victorian Curtain methot. Hold a pre-heated and cleaned plate at an angle and pour the MBDCG solution along the edges and along the top. Steeper angles make thinner coatings. This method works well, but the top of the plate will have a thinner coating than the bottom. MBDCG is very sensitive to variations in thickness of the coatings. If this becomes a problem, try the above method (Mold Coating). ===HOW TO USE THE PLATES:=== The plates can be exposed just like any other holographic plate. They are somewhat less sensitive than silver halide plates though. They need about 30mJ per square centimeter. Thicker coatings are less sensitive due to the fact that they are less transparent. Perhaps using less MB in thick coatings will compensate for this. After holographic exposure, the following counter intuitive trick will greatly improve your hologram: during a period of one seventh of your exposure time, expose the plate in diffuse laser light (ie just wobble the plate in your expanded laser beam). This will greatly reduce noise in your hologram. Also, the hologram will be less sensitive to variations in processing temperature. ===Next, process as follows:=== # Leave the plate several minutes in a tray with water. Do this until all MB has dissolved out. The lights may be turned on now as the plate has lost it's sensitivity. It is a good idea to give the plate an additional rinse under cold running water now to ensure removal of the last traces of TMG from the emulsion as TMG can contaminate the subsequent alcohol baths and reduce their effectiveness. # Dip the plate in a tray with warm water, about 30 seconds. First try a temperature of 25C. More about this later. # Very quickly transfer the plate in a bath of 70% Isopropylalcohol and 30% water. Leave it in there about two minutes. This must be done in one smooth and fast movement because no water is allowed to dry or flow off the plate in between the water bath and the first alcohol bath. # Dip the plate in a bath of 100% Isopropylalcohol. (about two minutes) # Dip the plate in a second bath of 100% Isopropylalcohol. (about two minutes) # Put the plate on a dry towel (emulsion up), and dry it with a hair dryer set to HOT. If all went well, you will see an image slowly appear. If you see some crystalline structures appear on the plate, continue to blow dry. They will disappear again. (This is an indication that the optimum temperature for step 2 has been reached.) # If the hologram looks blue or dark green and is very dim, it can be re-processed. Starting at step 2. But this time at a slightly higher temperature. The hologram will come out brighter this time. At a certain temperature, the hologram will finish at a very pretty golden colour. It will be broadband now and not have so much depth. If processed at a higher temperature than the one that results in the golden colour, the hologram will be noisy and milky. Low temperatures in step 2 make very sharp narrow band holograms. Higher temperatures make less sharp broad-band holograms. ===Cristiano posted this recipie=== Hi, MBDCG is a tricky job. In my experience many variables should be tuned in order to get good repeatable results. For example, gelatine strength has a great impact on the warm water bath temperature. Coating drying time, as well as room RH, influences sensitivity. MB concentration, coating thikness, gelatine/TMG ratio, IPA baths temperature and so on make the situation more complex. Speaking about MB concentration, more MB dissolved in the emulsion makes the emulsion more sensitive but, as MB adsorbs red laser light a Denisyuk hologram will result dim. There are infinite scenarios. Here is my definitive MBDCG formulation *Pig gelatine 280 Bloom 10 g *Potassium chromate 1 ml (5% water sln) *TMGA 6 ml (25% water sln) *TMG 1.5 ml (25% water sln) *Methylene blue 2.5 ml (0.4% water sln) *Water 80 ml Adjust pH to 9.3 with 25% TMG sln Emulsion preparation * swell 10 g of gelatine in 80ml if cold water * heat to 40-45C to dissolve gelatine -never exceed 45C otherwise gelatine strength migth be altered- Stirring continuosly @40C: * slowly add 6ml of 25% TMGA (~ 1ml/sec) * add 1.5ml 25% TMG very slowly (~0.1ml/sec) constantly checking the pH that never should rise above 9.5. Correct the pH with 10% acetic acid. * slowly add 1ml of 5% Potassium chromate solution (~ 1ml/sec) * slowly add 2.5ml of 0.4% Methylene blue solution (~ 1ml/sec) * stirr for 3-5 minutes the whole mixing process should require about 10 minutes. Coating * Mold coating technique using 80um spacers (3.1mils) * 6 hours @ 28C gelling time * before detaching the glass sandwich chill it for 1 hour @5C (this step helps to get a defects free coating) * dry in steady environment (air stream free) for 12hrs @28-30C 60-70% RH. Drying temperature and RH seems to have great influence on coating characteristics. Exposure * Once the holographic setup is ready, wait for about 30 minute to allow all components to stabilize * Expose for 20minutes with a power density of 20uW/cm^2 for a 200x200mm plate. NOTE: I'm using a 20mW He-Ne laser (JDS 1145-P) warmed for 3 hours. Development and finishing * After exposure wait for 15 minutes * Wash in cold water (10C) for 5 minutes * Gently immerge the plate in water @ 19 to 25C (this step must be accurately tuned in according to your gelatine characteristics) for 30 seconds * Dry in 95% IPA @ 20-25 degrees for 1 minute * Dry in 97% IPA @ 20-25 degrees for 1 minute * Dry in 99-100% IPA @ 20-25 degrees for 5 minutes * Force quick IPA evaporation with hairdrier * Finish the hologram in pre-heated oven @125C for 10minutes I hope this helps you. Cristiano ===THINGS THAT CAN GO WRONG:=== * Be careful with chemicals and read the relevant MSDS (Material Safety Data Sheets) each time before using. * If there are random variations in brightness across the processed plate, it has not stabilized to the ambient humidity yet, or it has not dried long enough. Drying can be accellerated with a hair drier set to cool. This can cause some dust to adhere to the plate though. * If the gelatin detaches from the glass plate during processing (usually happens during the washing bath in step 1), don't be tempted to take it out of this bath before all the MB has washed out. Putting a plate in Isopropylalcohol that is not clean, will contaminate this bath and make it useless. If you only use clean plates in the alcohol baths, these baths can be used many times. Detachment can be prevented with an extra pre-processing step during the cleaning of the glass plate as follows: Make the following mix: 40ml 3-amino-propyltriethoxysilane + 45ml IsopropylAlcohol + 5ml DeIonized water. After 24 hours, take 1ml of this stock solution and add 20ml IsopropylAlcohol. Rub a cleaned glass plate with this solution. A white haze will appear across the glass. Leave the plate for about two hours and clean again with Glassex (Windex in USA). The glass is now sticky to gelatin forever. Gelatin will not detach anymore from this glass. Mark the glass with a small dot of a black waterproof CD marker so you can tell the difference between a silanated glass and a Rain-X treated glass. * Plate is insensitive/very dark blue before exposure and takes more than 5 minutes to become transparent in the washing bath. This happens when the coating is too thick. Try a lower concentration of gelatin or less Methylene Blue in the stock solution. * There is foam on the gelatin solution before coating it on the glass. This results in ugly tiny air bubbles in the coating. Allow the MBDCG stock solution to cool and gell before using. When it has gelled, the bubbles are on top of the gelatin. They can now be cut out with a small plastic spoon. * Random colorations appear across the plate. This happens when you don't transfer the plate from the warm water bath quickly enough into the first alcohol bath. Try to cover the gelatin side with a cover glass or plastic sheet (while in the warm water bath) before moving it into the alcohol bath. Once fully submerged in the alcohol bath, remove the cover. * Random spots of Pretty Golden Area's appear across the plate (usually at the sides of the plate): Hah, you have found the threshold temperature in your warm water bath, above which the hologram becomes a golden colour. Re-process with the warm water bath one degree Celsius higher. ===USEFUL TIPS:=== * A great way to measure small amounts of liquids is to use a 10ml syringe. Use the type with rubber seals because they operate more smoothly. * A great way to measure small amounts of solids is to use a digital scale used to measure the weight of letters. Make sure that they have a resolution of one gram or less. * Stock solution stays usable a very long time. Do not allow it to freeze though. I haev re-used stock MBDCG six months after first mixing it. * Plates stay usable a very long time. I have exposed a plate that was two weeks old with no difference in sensitivity. * Unlike silver halide plates, MBDCG plates are very resistant against accidental exposure to light. In fact, I keep my ready-made plates in my house. Before exposure I quickly walk with them in broad-daylight to my garage and use them. Use a green light as a safe light. Don't worry if there is a small amount of red left in your safe light. MBDCG is not sensitive enough to be problematic with small amounts of red light. You can check the spectrum of your safe light by looking at it's reflection in a dvd. If you see only green, perfect!!! If you see some red, no big deal for MBDCG. * Unlike silver halide plates, MBDCG plates are very VERY SUPER resistant against accidental exposure to light. I think this is because of non-linear behaviour of the plates. I once tried to expose a plate that had been in my house uncovered for two days. Sure enough, a dim hologram could be made with it. :) * Don't be satisfied with a dim hologram. MBDCG holograms can be very bright. So bright in fact that you don't have to paint them black on the back side. You will not be able to see through a good MBDCG hologram when it is properly illuminated. * MBDCG holograms are somewhat sensitive to moisture. If you want to keep your hologram in good condition a long time, it has to be covered with a protective glass plate and sealed on the sides. If you don't do this, the plate will fade over time. The good news is though that you can re-process the plate. It will look as pretty again as when you processed it the first time. * Stock MBDCG solutions last virutally forever. You need about 2 ml to cover a 10x15cm plate. So you can make about 50 plates from 100ml of stock. You can make about a liter of stock MBDCG from the pre-mixing solutions above. * A 10x15cm plate needs about 3 minutes of exposure time at 50mW. And about 25 seconds of diffuse post exposure to harden the plate. * If you are in a real big hurry to mix MBDCG stock and don't worry about small lumps in the solution, the following procedure works well (I have never seen the small lumps, but some people have had them with certain types of gelatin): -100ml DeIonized Water -4.8ml TMG -Add small amounts of Boric Acid crystals until the PH drops to about 10. (about 0.77 gram total). -1ml Potassium Chromate (4%solution in DI water) -6ml Methylene Blue (Diluted to 0.4% in DI water) -Add 10g gelatin. -Check PH again. This has the added advantage that the gelatin dissolves much faster due to the higher PH and no air bubbles form in the solution. * If you store your plates in another location than the one where you expose them, they need some time to adjust to the temperature and humidity of the location where you expose. A quick way to adjust the plate is to blow it with a hair drier set to COLD for a few minutes. * You don't need a magnetic stirrer to mix MBDCG. Simply use a cheap hot plate. Put a pan with sufficient water on the hot plate and set the plate to a temperature of about 40C. Then place the glass container in which you mix the chemicals in the pan. The water in the pan now functions as a temperature buffer and will react more slowly to too high or too low settings of the hot plate. This also has the added benefit that PH meter and plastic spoons can be cleaned in the water that is in the pan. Don't allow the temperature to go over 50C. * Use plastic trowaway spoons for mixing and measuring chemicals. That way you (or your better half) will never make the mistake of putting them in the dishwasher or with the spoons that you use for eating. * Clearly mark all glassware and pots and pans that you use for MBDCG with a scary looking skull and write poisonous on them. Then store them in a place where children cannot touch. * Instruct family that ARE qualified and able to be close to the chemicals and equipment: If anything falls over or is noticed to be leaking..... WALK AWAY AND CLOSE THE DOOR!!! Then tell you what happened. ====Tips from Cristiano Perrucci:==== I would like to emphasize this method requires a few little adjustements: * MB concentration SHOULD be tuned for optimum results depending of gelatine hardness and tape you are using (mine is 3.1 mils) * Gelatine concentration MUST be tuned for differents kinds of gelatine and TMG concentration. * During gelatine pouring, glass plates SHOULD be controlled for better results, and kept closely to emulsion temp. * Traces of water repellent (I'm using Rain Clear as Rain X is unknown here in Italy) on glass surface helps to get a really smooth coating. ====SO-DCG for Green Lasers==== You can substitute MB with Safranine "O" and shoot with a 532nm laser and keep everything including concentrations just the same as with MBDCG). Safranine "O" is fully compatible with MB so you can do 2 colour ones. Exposures are the same as G307, however G307 can not be made panchromatic. 619e6c500c2cf3e68a5a07b38d27ee3ea68b45d4 0 571 2615 1837 2014-11-11T00:20:45Z Jsfisher 1 /* Gelatin */ wikitext text/x-wiki ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and Dichromated Gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300nm long and 1.5nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape(2,3,4,5,19). If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties(6,7). These two images were taken from source (16). [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion(6,8,9). Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions(13,14). [[Bloom value|Bloom]] (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the samplee a distance of 4 mm. The more rigid the sample the higher the bloom(13,14). This image was taken from source (16). [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them(10,12). Research is needed using vitamin C with CrVI(11). ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII (15). During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram(15). The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://en.wikipedia.org/wiki/Collagen # http://www.britannica.com/eb/article-72553/protein # http://www.lsbu.ac.uk/water/hygel.html # http://www.stanford.edu/~spark7/ # http://en.wikipedia.org/wiki/Gelatin # http://www.lsbu.ac.uk/water/hygel.html # http://albumen.stanford.edu/library/c20/kozlov1983.html # http://www.greatlakesgelatin.com/gelatin%20information.htm # http://www.cdc.gov/niosh/topics/hexchrom/ # http://en.wikipedia.org/wiki/Hexavalent_chromium # http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/ # http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf # http://www.gelatin-gmia.com/index.htm # Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora # http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html # http://sandwalk.blogspot.com/2007/02/collagen.html af1f4ae6db829cad38f07cada910c4395cebef5a 0 816 2616 1974 2014-11-11T00:23:33Z Jsfisher 1 /* FILM PREPARATION */ wikitext text/x-wiki == ABSTRACT == We review the properties and relative usefulness of 3 non silver Volume holographic recording materials that are available today. Dichromated Gelatin (DCG) will receive the most attention followed by Dupont Omnidex products and a light treatment of Polyvinyl Carbazole (PVK). Enhancement and control of color, bandwidth and diffraction efficiency of volume reflection holograms recorded in DCG and photopolymers is discussed. Methods of increasing the bandwidth while shifting the center frequency toward the red is given for photopolymers. Red pseudo color will be covered thoroughly so that the practitioner will have all the elementary tools to make full color and broadband DCG holograms from scratch. The entire DCG technology is disclosed as it relates to production of high quality display holograms that span the spectrum and may be narrowband and very deep or shallow and broadband. == MATERIAL == The list of volume holographic recording materials includes the silver halide films, photopolymers, photocrosslinkers, photochromics, ferroelectric crystals and a few less well known oddities. While useful devices may be made in all these materials only a few will provide a holographer with a sufficiently high index modulation, resolution, signal to noise ratio, spectral response, and archival properties. The silver halide films have grain size limited resolution, scatter short wavelengths excessively, have only a moderate index modulation and tend to print out in UV light. They are popular for many applications because they can be made panchromatic, are much more sensitive than any other materials and are commercially available. We ocassionally use silver halide films to make master holograms and we reduce the blue scatter by converting them to a gelatin hologram (SHG). Used in this manner they are nearly equivalent to dichromated gelatin (DCG). They enable the production of DCG masters shot with red light at silver speeds that can be copied with green light in DCG and reconstructed finally at the original red color. SHG processes are covered in previous publications. The three materials detailed in this paper were chosen because they each have more or less all the properties needed for the construction of high quality or high efficiency broadband or narrowband color controlled holograms. They are not without faults however and the purpose of this work is to provide information to a holographer to assist him to make a better material choice for a particular task or to set up for production in DCG. Some information is given relating to the peculiar drop in average index in DCG, PVK and DMP128 due to the nature of the index modulation in these materials. Very thick coatings, up to about 50 microns are also dealt with in a special section. Comments made about preparation, processing, fine tuning, protection and applications are based on many years of working with DCG and many months of working with the other two materials, Dupont's Omnidex materials and Polyvinyl Carbazole (PVK). DMP 128 is another well documented material. It is a proprietary Polaroid formulation of lithium acrylate in combination with a branched polyethylenimine. Although it is not generally available commercially Polaroid has allowed laboratory evaluations and it is now quite common to get holograms mass produced in the material at Polaroid. Several other photopolymer systems are possibilities for holographic work but these 3 represent the readily available and practical recording materials of the day. == REFLECTION HOLOGRAM FABRICATION STEPS == === Mixing and coating === DCG is a mixture of Ammonium dichromate, gelatin and water. It is stirred together, heated, filtered and spun on or drawn down with a bar. Drying with or without heat from gel or liquid states makes little difference. Bright yellow lights are permissable. A 10 micron film can be made by mixing one gram dichromate with 3 grams of gelatin and 20 grams of water and spinning a flooded 8x10 glass plate at about 80 RPM. The solution and the coated plate is useful for about 3 days, much longer with refrigeration. PVK is dissolved in chlorobenzene along with Carbon tetraiodide, it is difficult to get into solution even with heat and agitation. It is also very unstable and may gel in as little as 15 minutes after mixing. The solution may be further thinned for convenient spinning but is easily applied with a bar. A number 28 bar will yield a 5 - 7 micron coating when 2 grams of PVK are dissolved in 25 grams of chlorobenzene. The patent disclosure mentions nothing about mixing the sensitizer with the PVK while still dry but if this is not done the solution will likely not be photosensitive. The solution will usually remain stable enough for coating for about 1 hour after mixing. The coated substrate is good for at least 8 hours. Dupont's materials can be purchased already to use on plastic substrates or may be obtained in liquid form for coating by any of the techniques covered here. === Storage after coating === DCG stores well at low humidity in a refrigerator or freezer but containers must prevent contamination, condensation, freezer burn and frost which can all destroy surface quality. Film of 10 to 20 microns or more store best and are good for at least a year. At room temperature and 50% RH, thin films are good for a few hours, thick films typically last a week or more. The addition of a small quantity of TMG to the mixture will greatly increase storage time at room temperature by increasing the PH. PVK does not store well as a rule, sometimes it has lasted a week in the refrigerator. Typically it moves suddenly to insensitivity within 24 hours and it does not seem to age gradually. The instabilities in coating and storing could be alleviated by adding more antioxidants to retard the spontaneous formation of free radicals but at the cost of reduced photo sensitivity. Dupont's materials seem to store well under refrigeration for a year or more depending on type, their newest film is also very sensitive, requiring only a few mj/cm*cm to expose in red or green. === Exposure characteristics === DCG is most sensitive in a hot moist environment. At 50% RH and 68 degrees F it may require 60 mj/cm*cm of 488 nm light, while at 75% RH and 80° F 4mJ/cm² will do the same job. At 441 nm less than 1 mJ is enough and at 514 or 532, 50 to 100 may be necessary. The percentage of dichromate affects speed more or less linearly, a 25% mixture is typical but mixtures of from 10 to 30 percent are necessary to control color. Gross overexposure will cause a decrease in efficiency all the way to zero. Overexposure causes an initial increase then a decrease in bandwidth and a blue shift plus a compression of contrast or dynamic range. PVK is totally insensitive to moisture, water can be used as an index matching fluid with no effect on the hologram. It requires about 20 mj/cm*cm at 488 nm to make a good single beam reflection hologram and because it is a cross linker it can be overexposed. Over exposure also results in a blue shift, a wider, then narrower bandwidth and loss of contrast. The Dupont material is a real time material and as a result can interfere with itself during an exposure. As the hologram is forming it is also reconstructing and making small dimensional changes. The results can be that at some time during an exposure the reconstruction could be out of phase with the construction momentarily. The energy required varies from about 8 mJ/cm² to a 100 or so mJ. It has good resistance to water and readable holograms have been made by us in 100ms. === Processing procedures === DCG is hardened briefly in Kodak Fixer with hardener then rinsed and plunged into several hot or cool alcohol baths. Cool baths produce better uniformity and lower noise, hot baths can yield tremendous index modulations with large chirps in Bragg spacing but often with increased noise. Depending on the mixtures, temperatures and times spent in each bath, a wide range of effects can be had. Processing and reprocessing affects bandwidth and center frequency over 100 nm or more and index modulation can be varied from near nothing to .25. If the first pass in the baths produces a shift to red, a second pass can shift it to blue and a 100 nm bandwidth can be reprocessed to yield a 30 nm bandwidth. Typically "master" holograms are processed to construct near the recording wavelength but processing and dichromate content allow the control of color to range from 650 to 450 nm for a straight on exposure at 488 nm. This much versatility in color control is certainly useful and will be covered in more detail. Conformal mirrors on flat substrates can be color shifted easily with angle but more complex shapes must be tuned with processing and film formula juggling. As an example of a reprocessing procedure, a red shifted broadband mirror may be narrowed and blue shifted by agitation for 30 seconds in a room temp 50:50 mixture of water and alcohol then plunged into 99% hot alcohol with agitation for 30 seconds and pulled slowly from the hot bath. The direction of the shift can be controlled by the ratio of alcohol and water in the first bath and the amount of shift can be controlled by the time in the same bath. A near ideal tuning bath has a specific gravity of .86 when it is warmed to about 55 degrees C. This process can be repeated many times if necessary, especially if the last hot bath is not hot enough to cause excessive scattering center buildup. Multiple buffer baths between the first color control bath and the last dehydration bath help to keep the last bath clean. PVK is swollen in Xylene or Toluene for a few seconds then dried in warm Hexanes or Hexanes mixed with alcohols. Like DCG the latent image must be enhanced by swelling in the first solvent and then replacing that solvent with a miscible but nonswelling solvent. Again, color and modulation control is by temperature and time. Color control is similar to DCG methods and either broadband red shifts or narrowband blue shifts are possible by altering time and temperature. Reprocessing is possible but scattering centers build up rather quickly in this material. The first solvent probably dissolves away material as it causes swelling. Signal to noise is usually good in narrow band processing but not so good for broadband reconstructions. A recent proprietary improvement in processing involves the use of a clever monobath made up of two miscible solvents. One of the solvents will swell the PVK and is more volatile than the other solvent which will not soften or swell the PVK. The most volatile solvent evaporates first and leaves the hologram structure in rigid uniform shape while the second solvent is driven out with warm dry air. Dupont films are developed with UV light and heat. They may then be brightened and color shifted by the addition of monomers and or solvents. It is common practice to laminate a cover glass over gelatin holograms to protect them from moisture, abrasion and chemicals. Many common epoxies have been identified as safe for this purpose as well as a broad class of adhesives described as UV polymerizable substances,( monomers, epoxies, resins, adhesives, etc). I accidentally caused an enhancement of several photopolymer holograms while attempting to laminate them. In one case the bandwidth widened from 40 nm to 150 nm and the optical density remained almost as high as the original structure. The photopolymers behave a little like sponges that can be dampened and swollen or alternatively soaked and saturated while the shock dried DCG and PVK structures are more like a stack of Ruffles potato chips that get damp, go limp and then collapse. Enhancement of Dupont photopolymer is the easiest and most reliable. The holograms produced from blue exposures originally playback blue but the enhanced holograms playback at a longer wavelength and are noticeably brighter. Solvents alone brighten and shift the reconstructions to the red but they are temporary treatments and not generally as effective as UV curable monomer type adhesives. A Dupont product is now available to make predictable shifts in playback color. They provide a monomer on a cover sheet that will diffuse into the exposed film where it causes swelling and can then be fixed by polymerization under a UV source. Some Dupont film reflection holograms will respond to the following recipe with a red shift and increase in total diffracted energy. Apply Lightweld 401 evenly and cover then wait for a color change and cure with strong UV source. If this substance is left uncured it may destroy the original structure. It is also anaerobic and therefore requires a cover to cure. === Protection === DCG is notoriously bad at remaining stable in normal environments. Moisture will cause the Bragg structure to collapse and the gelatin grabs moisture easily from the air right through most plastics and glue. This material usually requires lamination between glass with enough gelatin removed around the edges to form an "O" ring seal. Thick plastics, such as 30 mil mylar, will also work and certain fluorinated plastics such as "Aclar" in thin 5 mill layers are satisfactory provided that the edges have been cleared of gelatin before laminating. PVK needs protection from abrasion but it stands alone as the only holographic material we ever worked with that is completely waterproof. It requires only a 4 mil mylar laminate for adequate abrasion protection from the environment. Dupont's materials may be used as is or uncovered and rolled down onto a glass substrate. They need very little protection after being fully polymerized with UV light but a stiff flat backing helps with image distortion. Water can affect them temporarily but the structure is essentially humidity proof. == APPLICATION NOTES == DCG is easily the most versatile material, just about any kind of HOE or hologram can be made in it. Unfortunately it has poor environmental stability and must be well protected or it may not be intact when you need it. As long as glass or thick plastic is acceptable in the finished product DCG is the number one choice. With some difficulty it can be made panchromatic for full color work and under warm moist conditions it is a little more sensitive than the other two in the blue-green region. The SHG versions are much more sensitive and represent the only fast "non silver" medium useful for pulse holography applications. PVK is not so pleasant to work with as DCG but it goes onto plastic substrates easily, has a high delta n and needs only minimal protection. It should be very good for such things as eyewear, solar collection and other outdoor applications or anyplace where superb environmental stability is required. Dupont's materials come with an ever wider range of properties. They are durable and panchromatic but lack a little in dynamic range. The maximum available index modulation is lower than the other two materials and display holograms are typically less bright. Initially we tried to determine the index modulation of simple reflectors made in each material by fitting them to the simple one dimensional Kogelnick expression for diffraction efficiency (D.E.) of reflection volume holograms. {| border="1" |- ! colspan="2" | Kogelnick Expression |- | <math> DE = \tanh^2 \, {{\pi\Delta n T} \over {\lambda\sin\Theta}} </math> | Where *T = thickness of material in microns *λ = .5 microns (typical) *sin θ = 1 (for conformal mirror) |} This relationship seldom describes real reflection structures because it does not describe the effects of a gradient on the index modulation (delta n) or a chirp in the grating spacing (d). A gradient in delta n such as is caused by the absorption of light by the sensitizing dye results in a smooth broadening of the angular and spectral bandwidths and a smoothing of sideband peaks (when DE is held constant.) A chirp in the Bragg plane spacing also broadens the bandwidth though not so smoothly and the combination produces a highly asymmetric spectral bandwidth. The data and a description of the computer model is given in a previous publication. All three materials exhibit a useful range of index modulation and color control and each has found multiple commercial uses. The differences lie mainly in sensitometric characteristics, environmental stability and in the degree of difficulty to obtain or use. The balance of this paper will detail the use of DCG. We will try to give instructions that can be followed by anyone that is already familiar with more conventional holographic fabrication techniques and materials. Some details are left out for the sake of brevity but can be found elsewhere in the references or other literature. == SPIN COATING APPARATUS == A variable speed turntable capable of 50 to 100 RPM will coat films of gelatin or PVK from 4 to 50 microns on 8 x 10 inch glass or plastic substrates. Plates as small as 3 inch diameter or as large as 16 x 16 inches have also been successfully coated with this range and technique. The turntable should be equipped with a surface or arms that will mate to a removable tray that is one or two inches larger than the substrates being coated. We have used ordinary variable speed phonograph players with pie tins turned upside down and glued to the turntables and we have used Dayton variable speed gear motors with heavy duty arms attached. Both devices worked very well. Trays have been made up of stainless steel, plexiglass, polyethylene dishpans or modified from aluminum cake and pizza pans. The best trays have straight sides measuring 2 1/2 to 4 inches high and are fitted with 3 rubber posts inside and outside. The posts inside hold the substrate an inch or so off the bottom of the tray and the outside posts serve to level the tray during pouring of solutions and to center the tray during spinning. The spinning tray and substrate may generate useful turbulence that aids in drying and distributing the solution. Excess solution is caught in the tray and emptied between substrates then is easily soaked clean in hot water after a days activities. An important component that augments drying and uniformity is the blower-heater. It hangs off center and above the whirling tray. Turbulence and heat combine to make uniform coatings in about five minutes. We recommend the use of a variable temperature 600 watt blower such as might be found in the ceilings of some bathrooms. A little experimenting with angle and position will quickly determine the best place to hang this unit in your clean hood or bench area. Coat and examine uniformity by looking for local fringe patterns under a fluorescent lamp or better yet a fluorescent long wave black light. == BAR COATING APPARATUS == Lab coating bars are available from R.D. Specialty Co. in Webster N.Y. Ph (716)265-0220. A selection of bar types may be purchased for about $ 50.00. We have used bars of 3/8" diameter wound with # 24 wire as a standard but we have other windings and diameters on hand for special applications and recommend you do the same. These bars are also useful for applying strippable coatings for anti halo backings, and have been used for coating photopolymers and protective epoxy layers etc. Jigging for bar coating can be as simple as a clipboard with lint free paper placed under the substrate. A better jig is one that holds the plate above a trough that can catch run-off. The whole thing can be plexiglass which is particularly easy to get gelatin off of and it also preferentially over glass attracts dust particles. Bar or spin coating is done in a class 100 environment and is accomplished by pouring out a line of solution and pulling it down with a uniform pressure and velocity. A little practice will determine correct amount of solution, speed and pressure. The bar is not rotated as it is pulled and a new location or freshly cleaned and dried bar is used on each new substrate. Variations in thickness may be accomplished by changing wire size or viscosity or both. Precautions must be taken to keep the bars clean and undamaged. We place used bars in warm water and rinse and dry them before each use. A rack that holds them suspended above any surfaces is useful for storage, cleaning and serial use. It can be made from plastics or metals. Coated plates need to be placed in a level position where they can air dry in a few minutes. The coating jig should be nominally level. Cronar, (polyester) substrates are easily coated with these bars. Cronar is a Dupont product. One source is Farrest Chemical &amp; Supply, 680 Toland St., San Francisco, CA (415)8241400. It is available in sheets (C-42) or rolls (C-41) in a variety of sizes. Exposure of Cronar is done with a thick glass vacuum chuck or by humidifying the gelatin and rolling it against a clean glass plate. It is optically active and you may need to identify its neutral optical axis before exposure. Processing is best done by stretching it in a frame for dipping and agitation or by clipping it flush to a glass substrate fitted with a handle on one side. == FILM PREPARATION == Many factors need to be considered when mixing DCG for holographic film. === Jelly strength === The jelly strength, measured with the Bloom Gelometer, is an important consideration. The current gelatin being used by us for film production is either MCB brand (Mattheson, Coleman, and Bell Manufacturing Chemists, Norwood, OH 45212 # GX-45' OH 45212) # GX-45. Grayslake Type B USP XXIII Box 248 Grayslake,IL . 60030 Phone (312) 223-8141 Contact Bob Buscher. Both gelatins have [[Bloom value|bloom strengths]] from 215-235. Comparable with the jelly strength is the rated solubility of the gelatin, and the mode of manufacturing. (Acid or Alkaline processed.) These can each make a considerable difference in the quality for each lot. It is best to test every specific lot before final acceptance of a gelatin. Perhaps the best rating for gelatin to be used for DCG is the jelly strength-to-viscosity ratio. A ratio of at least 4 or 5 to 1 is considered good. Our current batch has a [[Bloom value|bloom]] of 232 grams, a viscosity of 42 mps and a ph of 5.1. === Heating === One important caution when preparing the DCG film mixture is the destabilization of the gelatin at high temperature. When heated for an excessive period of time, the film breaks up, causing what we term as film "pits" in the final emulsion. These "pits" have the appearance of small circles of various sizes and scatter themselves throughout the plate. When the film is processed, the final image has small voids where the "pits" were. So far, the length of the heating time and the peak temperature that cause this have not been determined. In the past, temperature and heating time causing this have fluctuated. But the safe method is to heat the film mixture at the shortest possible heating time to dissolve the gelatin content completely. 130 F to 150 F (60 C.) is usually a high enough temperature to dissolve without cooking. Gelatin "melts" around 40 to 45 C. The causes of film "pitting" are still unknown to us as well as what the "pits" really are. But their characteristics (and that of gelatin) can give us some ideas. It is important to take all known preventative measures for keeping them off the emulsion. Triple filtering helps and avoiding hot spots while mixing helps. We use a standard mag stir hot plate and glass flasks which are heated slowly while stirring or heated in a water bath, a microwave oven has also worked well using plastic bottles . Film "pitting", or destabilization, in the past, has seemed to be affected by the solubility of the gelatin. The higher the solubility, the less likely film "pits" occurred. The solubility, of course, is slightly affected by jelly strength and impurities. Literature within the gelatin film industry indicates temperature separation may occur, partly due to the polysaccharide content of the gelatin. There is one speculation of film pits which involves the crystallinity function in drying films. (And this is a function of film temperature.) The other theory for film "pits" is the presence of insoluble impurities (such as arsenic, grease, etc.) on the surface of the film. These substances probably conglomerate during mixing and heating to make larger hydrophobic areas on the glass. Surfactants would alleviate this but they aggravate adhesion problems as well. === Water === Use deionized water for the DCG film mixture. It eliminates certain salts which have produced inconsistencies in film behavior. Distilled water is also acceptable. Any water should be funnel filtered through a 5 micron or smaller filter and be free of oil, grease, and bacteria that thrive on gelatin. === Storage === Film mixtures may be stored in a refrigerator for a week or two and reheated in water or a microwave oven as needed. When stored longer the become less and less likely to flow when warmed. === Film codes === The film mixtures vary in dichromate and gelatin percentages. The variations depend on the specific use that a DCG film plate has. The film code currently used contains three numbers. The first being the gram-weight of the ammonium dichromate, the second being the gram-weight of the gelatin, and the third being the gram-weight (mls) of the water to be used in the film mixture. (Usually mixed in a 500 ml poly bottle.) The code for film used in broadband image holograms is 8-30-350. Thus, 8 grams dichromate, 30 grams gelatine, and 350 grams (mls) of water are mixed together. The mixture code for "red" holograms is 3-30-200. Most holographic optics are made in 10-30-250 to 8-30-150. Very thick coatings of 30 to 50 microns can be made using a 3-30-125 mixture but special fixturing may have to be made to get the gelatin to flow uniformly and the dried film may come off the substrate unless it is baked on at high humidity. We find adhesion is enhanced by cleaning the substrate in clorox and then baking the coated plate at 130 degree F in the presense of water at saturation. In using the film code for a variety of mixtures, the 30-gram gelatin weight number always remains constant. Thus, when a thicker emulsion is desired, the water number decreases. And when more absorption is desired, the dichromate number increases, an increase in thickness narrows the bandwidth and an increase in dichromate shifts the color toward the blue. As a general rule, thicker emulsions require longer process times but are easier to make uniform. The dichromate concentration determines light absorption and the center reconstruction wavelength of the hologram. For higher dichromate concentrations, the increased absorption produces larger gradients of index modulation. Lower the dichromate concentrations produce more uniform index modulations. Larger gradients yield slightly larger bandwidths and the removal of higher percentages of dichromate during processing results in thinner and thus bluer holograms. When a specific bandwidth is desired, along with a specific reconstruction wavelength; it is best to experiment with various film mixtures. Usually starting with a standard mixture and then adjusting the thickness, and dichromate content to achieve the desired results. The color controllability and uniformity of DCG film improves with thicker film emulsions. Consequently, they are more forgiving in their exposing and developing parameters. Extremely thick (25 micron or more) emulsions ( X-30-150, a 5 to 1 water-to-gel ratio) are difficult to use. They are prone to excess bubbles, pre-mature jelling, film pits, low viscous flow, increased impurities and during processing sometimes pull up off the substrate if not annealed in a wet oven. Processing of these thick films is often done with room temperature baths, or slightly elavated temperatures, over several minutes in each bath. === Sensitizer === We use ammonium dichromate crystals or for redder reds Potassium dichromate but the most sensitive of the dichromates is Pyridine dichromate. We don't use it because of it's shorter life and difficult preparation. The addition of ammonium nitrate can make the dichromate several times more sensitive, but decreases the useful life and blue shifts the image. Approximate ammonium nitrate concentrations are usually in a ratio of 1 to 5 by weight to ammonium dichromate up to a maximum of 1 to 1. When the additional substance is washed out of the gelatin a net shrinkage occurs which amounts to a blue shift in reflection holograms and lays down Bragg planes in transmission holograms. === Filtering === At a minimum, filter the heated mixture through two coffee filters (Mr. Coffee) for a standard 8-30-350 film. For 6-30-200 and thicker emulsions, use one coffee filter. Run the filtered mix into the pouring container. When necessary, a finer grade lab filter may be used, we have forced warm gelatin through a 1 micron filter using a gear pump and also using a peristaltic pump. The use of a peristaltic pump makes metering and filtering possible at the same time. A simple syringe with a 2 micron filter is very effective and may double as a way to meter out a fixed amount onto a plate. === Applicator === The pouring container (with the film) is kept on an electric warming plate. The temperature of the plate should be carefully controlled to provide only enough warmth to prevent jelling (50-60 degrees C). We like to use a lab hot plate and water bath, the pouring container is a tea pot like bottle modified from a lab wash bottle. Any poly bottle that empties from the bottom will do. Some custom shaping of the "spout" may be necessary to prevent the formation of bubbles. == COATING TECHNIQUES == The coating station consists of a class 100 cleanhood or laminar flow bench, a dryer-heater unit and the turntable. The clean hood should be large enough to fit the turntable and two plate racks inside. (About 2 1/2' x 3 1/2' or larger.) A yellow safelight may also be mounted inside. Air flow should be 200 cfm or higher for this size hood. === Cleaning glass === There is a bit of an art to coating and it takes a little practice to become good at it. The first step is to prepare the plates by soaking over night in a soapy solution that contains some chlorine. The plates also need scrubbing and a rinse in deionized water. The final rinse should be done in or in front of the clean hood used for drying the plates. The chlorine soak has been found to aid in adhesion of the gel to the glass. The glass may be soda lime plate or float glass or any most any other kind but it has to be thick enough to withstand the shrinking forces generated during exposure. This means that it should be double strength or thicker(3 to 6 mm) for 8 x 10 shots, single strength (2 to 3 mm) for 4 x 5 and 5 x 7, and may be picture glass or as thin as 1 mm for 2 x 2 exposures. === Coating glass === The gelatin is poured over the dried plate in such a way that no gel spills off the edge and no bubbles are formed. This is accomplished by pouring a large puddle and gently rocking the tray till all edges are wet. The turntable is then turned on with the blower/heater for about 5 minutes. If the plate was uniformly wet and had no contaminants then the coating is likely to be uniform using these techniques. The range of RPM we found useful runs from 65 to 100, speeds outside this range failed to be uniform. Start with a rotation speed of about 80 RPM and position the heater-blower about 6 inches above and to one side of center of the coating tray. For 8 by 10 plates this offset is about 3 inches. The fine tuning of the position of the blower will greatly improve the uniformity of your coatings. === Ageing and thickness === The film is ready for exposure after it has been aged an hour or so for a 350 mixture or a day later for a 150 mixture. The addition of 1 or 2 ml of TMG will extend the useful room temp life of 350 film to a day or two and will make 150 film last for several weeks in a 21 degree C, 50% RH environment. The thicknesses of the commonly used mixtures after spinning at 80 RPM and after processing are as follows: 350 yields 5-6 microns, 250 yields 8-9 microns, 200 yields 10-12 microns, 150 yields 20-24 microns and 125 yields 25 to 50 microns depending on speed. === Bandwidths and color === The relative bandwidths run from 50 to 150 nm for 350 film, depending on processing used. 250 and 200 film make 10 to 50 nm bandwidths depending on processing and 150 film can get down to 8 nm but also runs as high as 30 nm. Very thick film can have bandwidths of less than 8 nm. The color of a film made from a 3-30-200 mixture is around 630 nm when shot at 514 nm. The color of 6- 30 film is around 590 for a 514 shot and a 10-30 mixture will easily be tuned to play back at the same wavelength it was shot at. Methods of planning and controlling color in display holograms are discussed below, similar but more precise methods are used for HOEs. == COLOR DICHROMATE OBJECT PREPARATION == The two color method produces rich red-orange and bright clean blue-green colors that mix to a creamy white. Color coding of the object is optional but helpful in most cases and production is done from two masters in two different films. The three color system requires color coding for red at the mastering stage but no coding for blue or green, which are mastered first. Both systems are part natural, part pseudo color and require only two laser lines and two film formulations. Blue is obtained naturally by using the 458 argon line and green or red are derived from the 514 line. In production the two color system is identical to current master/copy methods in that batches are shot at 458 or at 514 and later registered and laminated together. The three color system requires blue and green exposures in the same emulsion and red in a second batch. The laser must then be operated multiline or be switched constantly or a second laser introduced. The preferred method is multiline operation with independent shuttering except that max power in each line is reduced because several lines compete for available energy. The two color, two plate system makes very satisfying flesh tones and color balance is fairly easy to maintain because it can be done by mixing and matching batches and or individual holograms at the laminating stage. The two color single plate method has the obvious advantage of no registration problems but it has a limited color range because there are only 56 nm between 458 and 514nm. === Object preparation === Blue-green areas should be overcoated lightly with a bright blue pigment such as Liquitex Brilliant Blue #20002-381 or Pelikan Deep Blue #39. This will effectively inhibit refection at 514. The red-orange areas must be touched up with yellow pigment such as Liquitex #1002-411 or Pelikan Yellow #10 both of which absorb 458 but reflect 514. At this stage H1 masters or correctly colored copies can be made, the Blue-Green master may be made to reconstruct at 488 so that production copies can be done using only 488 and 514. The 514 exposure is done with the film side facing the reference beam and the 458 exposure is done the other way around with a spacer between the object and film having the same optical thickness as the 514 substrate. === Film preparations === A good blue or green production film can be made by mixing the 8-30-250 formulae with or without a ml of TMG. A good red or yellow film is made by reducing the amount of dichromate to 2 or 3 grams. The plates are ready to use after standing at room temp for an hour and they may be stored in a refrigerator for months on end. Better results may be obtained from some softer gelatins by ageing films for a few days. === Exposure procedures === Blue holograms may be made by exposing in a Denisyuk fashion @ 458, 441, 476 nm or some other line bluer than 488. The energy required is about 20 mj/cm*cm and it helps to do it with the reference at 50 degrees from the normal and with the E vector perpendicular to the plate to reduce noise from mirroring. Green holograms may be similarly produced by using the 514 line, again near Brewster's angle. This time it may pay to try 55 degrees because absorption is much lower @ 514 so "Newton's wood" type noise is more likely to show up.The energy required is about 90 mj/cm*cm. Red holograms result from using the red film formula and exposing @ 514 close to Brewster's angle. The fringe structure is expanded to red or yellow reconstruction because less material is washed out during development. If the master has been made in SHG using a HeNe then this copy will be a correct color reproduction. === Processing procedures === The film of gelatin is about 8 or 9 microns thick and requires much longer processing times than 4 or 5 micron broadband films. Development takes 3 to 5 minutes in kodak fixer, followed by a 1 minute rinse in tap water. Dehydration is done in warm isopropyl alcohol (48 to 55 degrees C) using at least 2 baths after the tuning bath and agitating mildly in each for about 30 seconds. Drying is most easily done by removing the plate very slowly from the last and driest bath. If it does not look uniform try soaking in warm water for 10 minutes and then dehydrate with more agitation. Fine tuning of the color may be done by soaking in the tuning bath. This is the way that we get the center reconstruction frequency to match the copy wavelength. Start with a master that is a little too red and gradually tune it to the correct color by repeated passes through the tuning bath and the last hot dry bath. 350, 250, and even 200 mixtures all respond to this method. A hydrometer is necessary to monitor the specific gravity of the tuning bath and maintain it at or near .86. Processing 350 film for masters is done this way but the same film can be processed for broadband reconstruction by using a shorter development time and skipping the tuning bath. Experimenting is the only way to get the desired results. Some guides to broadband techniques can be found in the proceedings of the first Lake Forest symposium in 1982. An alternative to multiple bath processing has been proposed by workers at IBM. They suggest that for thin films, on the order of our 350 or 400 mixtures, spinning the plate while spraying a series of fluids works best. Thin films are not easy to process in baths because of the fast diffusion of solvents in and out of the rather porous gelatin. In the IBM method, all of the regular baths are sprayed progressively for only a few seconds each onto the spinning plate. They felt that the spray system would be a superior way to automate processing techniques, we experimented with spraying many years ago but did not have the success that IBM has had. == HAZARDS == Dichromate powder is dangerous if inhaled and the liquid mixture may irritate some people if left on the skin. Dust masks and rubber gloves are therefore recommended whenever film is being made. Isopropyl alcohol has low toxicity but is quite flammable and must always be heated in a safe manner such as in a water bath. Alcohol fires may be extinguished with water, dry chemical, Halon or CO₂. Glass must be handled carefully and whenever possible the edges should be ground before handling. == REFERENCES == These references are all by the same author and may be useful to the holographer that tries to apply the methods detailed in this paper. A design guide and brochure for HOE's is available on request. A video tape demonstrating this technology is also conditionally available from the author. *"Devices, Tuning and Quality Control in Dichromated Gelatin (DCG)." S.P.I.E. Proceedings, Volume 212, pp. 22, 1979 *"Notes and Considerations for the Dichromated Gelatin (DCG) Holographer." Lake Forest College Holography Workshop and First International Symposium on Display Holography, July 1982. Lake Forest, IL. *"Practical Polymers for Holography", Second International Symposium on Display Holography, Lake Forest College, IL. *"Materials for Volume Phase Holographic Notch Filters" SBIR #A 86-68 Final Report, U.S. Army CECOM, Ft. Monmouth, N.J. Aug. 1987. *"Alternative Volume Recording Media, A Qualitative Comparison" Third International Symposium on Display Holography, Lake Forest College, IL 1988 *"Survey of properties of volume holographic materials", SPIE vol. 1051, Practicle Holography III, 1989 p. 68 - LA, CA. *"Novel Enhancement of Photopolymers", SPIE vol 1212, Practical Holography IV, 1990 LA, CA. '''''Last modified on 4/8/99''''' [[Category:Rallison]] 0708c390c6466bcfe6dc74a67daa2ed26ce468cb 0 826 2618 2194 2014-11-11T00:26:45Z Jsfisher 1 /* My First 4" X 5" DCG Hologram */ wikitext text/x-wiki == Silver Halide Films and Plates == === Workin' out with Irena === {| |- | Tom B.: Same plates and technique as usual (BB-640, 6% TEA, lit for photo with OptiLed amber from about 1.5 m). The pics didn't come out as well this time, but good enough. The fringe pattern under the models is intentional - I calculated a mickey-mouse model of spherical wavefront interference and printed it out on cardstock as a background, but alas it moved a bit so it's dark under Irena's hand. [[File:Olympic.jpg|400px]] Here is a stereoscopic pair photographed from the hologram. Look through the image to get the two halves to merge into a single image. [[File:Olympic_stereo.jpg|400px]] More of Tom B.'s work is show-cased at http://members.shaw.ca/holopix/My_holograms.html, complete with a chronology of his ever-improving efforts. |} === My First... === {| | PeterZ: This is my first reflection hologram using Integraf holokit, with PFG-01. Exposure time was 25s, distance between laser and plate 37 cm. Not very good photo. I'll do another one using polarizing filter and camera with manual focus. [[File:PeterZ_first.jpg|400px]] |} == Litiholo Kit == === Simple Transmission of Car === {| |- | Transmission hologram by Arturo with Litiholo kit. [[File:Arturo_Liti_car1.jpg|250px]] [[File:Arturo_Liti_car2.jpg|250px]] |} == Dichromated Gelatin == === My First 4" X 5" DCG Hologram === http://holoforum.org/forum/viewtopic.php?f=7&t=764 {| | Stephen: Mold-coated with 240 [[Bloom value|bloom]] skin gelatin brought from eBay. Dissolved 7.5 g of gelatin in 50 ml deionized water heated to 40-45° C, then filtered the gelatin using filter paper and small funnel. I used 60 μm shims and 6 mm thick 15" x 4" float glass for the mold. Mold was treated with Rain-X and then heated with hair dryer prior to pouring gelatin. I soaked 2 mm x 15" x 4" float glass in a 5% hydrochloric acid solution (concrete path cleaner) for 24 hours. The glass was then scrubbed under running water, and then rinsed with deionized water. Finally, I treated the 2 mm float glass with silane, TOTALSEAL 7016 (used for epoxying glass). After pouring the gelatin and clamping the mold, I waited until the mold had cooled to the ambient temperature, then placed in the mold into the refrigerator for five hours. [Note: 30 minutes would have been sufficient for the gelatin to set.] Then the mold was removed from the refrigerator and the parted the plates. The gelatin-coated plate was allowed to air-dry at ambient temperature for 24 hours. The plate was then cut into three 5" sections. The plates were then dip coated in a 3% solution of Ammonium Dichromate (15 g AmDi dissolved in 500 ml deionized water and 5 ml Ilford Ilfotol). The plates air dried at ambient room temperature for 5 hours. The platers were exposed at 532 nm with a ref power density at the center of the plate measured as 432 mJ. My measured power takes into consideration the loss due to Brewster's angle, but no measurement of object beam power. I gave five minutes for dark reaction, then proceeded with the following development steps. All baths at ambient. * Kodak Rapid Fixer (diluted as per paper processing) until clear + 15 seconds. * Rinse in water. * Water tuning bath for three minutes. * Dehydration in 50%, 70%, and 91% IPA, three minutes in each bath. * Dehydration in 100% until diffraction was visible + 15 seconds. The plates were then reprocessed with the following steps. The first bath at 32° C and the others at ambient room temperature. * Water tuning bath for three minutes. * 70% and 91% IPA each for 15 seconds. * 100% IPA until diffraction visible + 15 seconds. The plates were then dried with a hot hair drier followed by 20 minutes on a hotplate at 100° C. The plates were then sealed with cover glass. Notes to self: * Don't get the mold too hot. * Double check which is the emulsion side before placing the plate in processing tray. * Don't dry dipped coated plate vertically. [[File:Test fixture.jpg|400px]] [[File:HOLO 1.jpg|400px]] |} === Mermaid === {| | Colin Kaminski: This is a 4x5" dichromated geletin reflection H2 hologram that Dinesh, Joy and I made at their lab in San Diego. Here is a link to their work: http://www.tripletake.com. I helped a little but really the success of this image was the result of their skills which they were very generous about teaching me. [[File:Kaminski_mermaid.jpg|400px]] |} === Musical Angel === {| |- | John Pecora: On the left, 488 nm, 30 second exposure, fixer, water, alcohol. On the right, also 488 nm and 30 second exposure, then water for 25 seconds, then fixer, water, alcohol. Both exactly the same except the water prior to fixer soak. If you look on the right near the head in the white hologram you will see a type of whiteness and it starts to blur into the angels head on the white hologram. It seems to be where the emulsion is thin. The emulsion actually seemed to crystalized. It's not that is it cloudy but it reflects the light off the emulsion like a white haze. The more more of an angle the replay light the more diffusely reflecting the haze is and the further into the hologram it moves (all the way over to about half way across the head where it is blurry). Also what I noticed is the hologram on the left, when dried with the hot air just dried and got brighter and shifted colors. The one on the right exhibited that white crystalization (not cloudy) that then cleared up and went away to yield the hologram. [[File:JohnFP_AngelMusic.jpg|400px]] |} === Compass 215M Test === {| |- | Dave Battin plays with his Coherent 215M running at just under 30 mW. This hologram was a 6 minute exposure using one concave mirror, rapid fix. and ''dip sensitizing method''. The dip sensitizing method involves the following: * Coat gelatin onto glass and allow to harden. * Dip hardened plates into solution of AmDi (15 g), H₂O (500 ml), and soapy water (10ml). * Allow to '''air dry'''. * Expose. [[File:Battin_215M.JPG|400px]] |} === Two Color Test === {| |- | Combined red and green beams by Joe Farina. [[File:Farina_DCG_marbles.JPG|400px]] |} === Two Color Figures === {| |- | Joe Farina: These were done with Jeff's MBDCG formula, except that boric acid was used to adjust the pH, and Rhodamine 6G was used as the additional green sensitizer. The exposure was a combined 532/633 beam, with 14mW for 532 and 20mW for 633, measured after the spatial filter, the holograms are simple SBR Denisyuk. Plates are about 5 X 5 inches, and the exposures were around 20 minutes. One of the figures was painted with a few colors (very crudely), and the other figure was painted silver. The silver-painted figure helps me to get a better grip on whether the hologram (as a whole) is more narrowband or broadband. The plate on the right has a serious flaw (but also the best color reproduction) because there is a patch across the lower faces and upper chests of the two figures. This seems to be where the emulsion overheated in the oven. (I made a mistake by laving the glass directly on the inner floor of a homemade oven, I will correct that next time.) The colors came out fine. The outer robe is green, the inner garment is red, the scroll is white, the skin tone is tan, the hair is dark brown, with some lighter brown areas. I'm surprised the scroll came out so white. These two wavelengths (532 and 633) seem to be capable of reproducing a great many colors, but of course anything containing blue won't show up. I'm confident that this exact system will work very well if blue is added, for full color. [[File:Farina_DCG_figures1.jpg|400px]] [[File:Farina_DCG_figures2.jpg|400px]] [[File:Farina_DCG_figures3.jpg|400px]] |} === Little MBDCG Holo === {| |- | Hans: Here is a sample of a MBDCG that I just made with my adjustments to the original MBDCG. Due to temperature/moisture in my garage, I would never have been able to do this in my garage with classical MBDCG as was invented by Jeff Blyth because of fading (crystallizing) of the MB in the plate. Exposure time was 5 minutes with a TEC controlled laser diode. The plate was processed as follows: * First a long wash (10 minutes) in cold water to wash out the chemicals. * A swelling bath at 26C. I found that for thick coatings, this bath needs to be at least one minute. Otherwise, dim areas will appear on the hologram. * 35% IPA at 25C, two minutes * 70% IPA at 25C, two minutes * 99% IPA at 25C, three minutes I use no fixer. Remember that in classic DCG, the fixer is needed to convert the Cr(V) to Cr(III). It is the Cr(III) that hardens the fringes in the gelatin. With MBDCG it is the Methylene Blue that does that job. Cr(VI) is converted directly to Cr(III) upon illumination, and thus eliminating the need for a fixer. In previous experiments I found a great benefit in using a hardener before the swelling baths. But because my hardener was getting old so fast, I started to experiment with post exposures. I found the effect to be similar. I prefer the post exposure method over a hardening bath because it cancels out two big variables: Temperature of the hardening bath and age of the hardening chemicals. With a post exposure there is only one variable: Post exposure time. Experimentally, a post exposure time of 1/7 of the normal exposure time seems to work fine. I just wiggle the plate in the expanded laser beam at about the same distance where the plate was when the hologram was exposed. I have not found a little difference in bandwidth between post exposed plates and chemically hardened plates. Post exposed plates indeed are a little bit more broadband. But that to me is a benefit. [[File:Hans_NewFormula1.jpg|400px]] |} 6319af147069187eded95dbe241a5f9b6e94e45f 0 835 2619 1721 2014-11-11T00:27:45Z Jsfisher 1 /* Materials */ wikitext text/x-wiki Jeff Blyth This is a remarkably simple way of making a holographic recording material. This is the way that we make a lot of holograms in our lab, and we find it to be by far the easiest method for making holographic plates. In essence, we treat a glass surface to make it chemically 'sticky', we coat that with gelatin, and harden the gelatin with chromium or formaldehyde. Once we have the gelatin film we then soak into it a silver salt, and subsequently soak in potassium or lithium bromide to precipitate an ultra-fine grain precipitate of silver bromide. The bromide solution also incorporates a dye to make the plate photo-sensitive in the required wavelength range, and with addition of a little sensitiser we can produce by this method a holographic plate of quite high standard. A worksheet (dated Nov 2000) is given below. It gives results which have good diffraction efficiency and photosensitivity compared to ultrafine grain proprietary material. But this is for the fun of doing it all yourself and getting bright results. If you are particularly concerned about marks from bubbles, dust and blemishes then you may prefer to use the proprietary material. The material on this page is based on the following article, with some changes that we have made to our protocols since publication, and any differences between the original article and the text below are solely due to those differences. == A simple way to make silver halide hologram recording plates by Diffusion == By Jeff Blyth Institute of Biotechnology University of Cambridge Tennis Court Rd. Cambridge CB2 1QT Tel: 01223 334152 (fax: 334162) email: jeff@biotech.cam.ac.uk What follows is in the form of a worksheet based on the paper published in ''The Imaging Science Journal'', Vol. 47, pp 87-91, 1999. A text only version of the paper can be found on the Internet at http://www.holoworld.com/holo/paper.html or at http://www.holografie.com/paper.html. === The Basic principle === A coating of pure gelatin on a glass plate is treated with silver nitrate. The coating is then immersed in a bath of bromide ion and dye. This then precipitates extremely fine grains of silver bromide in the gelatin layer. === Materials === # Presubbed glass plates. You can use old holographic plates with the gelatin removed with the aid of household bleach. # Gelatin of [[Bloom value|bloom strength]] between 250 and 300 (e.g. 300 [[Bloom value|bloom]] from Aldrich cat no. 27,162-4). You can use culinary gelatin without any sugar or flavourings. # Ascorbic acid or Vitamin C. # Silver-nitrate. A 1N volumetric standard solution is a useful form. # Potassium Bromide # Chromium acetate. You can use chrome alum instead. # Dye(s) #* Pinacyanol Chloride for HeNe 633 nm exposure. #* 1,1-diethyl-2,2 cyanine iodide for 532 nm exposure. # Sodium hydroxide # 3-amino-propyltriethoxysilane (for new glass plates). === Concentration of Solutions === Quantities will need to be judged by you to suit your requirements. * Silver nitrate: 6% w/v in (DI) water (or the 1N volumetric standard solution diluted by 1 volume to 2 volumes DI water). * Stock dye solutions. (In practice, you would probably only need one hundredth of a gram to make up a few ml of these somewhat expensive dyes.) ** for 633 nm: 1 g / 1000 ml Methanol. ** for 532 nm: 1 g / 500 ml Methanol. * Potassium bromide: 4% w/v in 3 / 2 methanol / water (3% lithium bromide gives a finer grained hologram than the equivalent concentration of potassium bromide, however 4% potassium bromide works well). * Chromium acetate solution: 1% or Chrome Alum, 2% * Gelatin solution: 15% (see 2 paragraphs down). * Ascorbic acid: 1% solution in water, adjusted to around pH 5 with any alkali. === Preparation of plates === Glass plates usually need a pre-treatment step or the gelatin coating will peal off. You can use old holographic plates by simply giving them a 10 min. soak in neat domestic bleach solution and then rub off the old gelatin layer under tap water. After a final rinse in distilled water, no further subbing step may be required. However with new glass plates, I leave them soaking overnight in a 100% bleach (Domestos or Parazone). After the plates are dry I rub them over with a 1% solution of 3-amino-propyltriethoxysilane in acetone on a tissue until it has evaporated, and leave them in air to interact with the silane for at least two hours before coating. (The silane solution has to be freshly prepared for each batch of plates). === Preparation of coating solution for a 10 x 8 plate === Add 30 g gelatin to 170 ml cold distilled water and mark the liquid level on the beaker. Place beaker in a water bath and heat while stirring constantly until gelatin solution is between 60 and 70o C. Stir until all granules have cleared. Top up level to the mark. To remove skin and surface foam, pour through a fine mesh (nylon stocking works fine) into a preheated beaker. Then immediately proceed to next step: === Coating (by the old Victorian curtain method) === Hold the beaker in your right hand and with you left incline the presubbed glass plate (preheated to around 70oC) at an angle of about 30o to the vertical with its bottom edge in a clean tray. Pour the gelatin in a line about 1 cm from the top of the plate. The pouring rate must be continuous until the furthest edge of the plate is reached. (You may have to accept the tendency of the coating to not completely cover the lower part closest to the furthest edge.) Lean plate against something for a few minutes while coating gels. Run a knife along thick layer at the bottom to free plate rather than risk tearing the delicate coating. (Since no hardener is involved yet the gel can be readily scooped up and re-coated if you are not satisfied.). Put plate in cold solution of chromium acetate for 1 minute. Shake off drips and then (without washing away that salt) blow plate with cold air until dry. Once the layer is dry leave the plate to complete the chrome hardening effect overnight in a warmer. (Preferably at around 60oC for several hours). Rinse the hardened plate in DI water and dry in a warm air flow. If you want to cut plate up for the next step then after scoring the glass on the back and cracking it, it is best not to pull sections apart before running a scalpel blade along the gelatin side first so that it is cut and not torn apart. Alternatively a Meyer bar can be used. About 7 turns per cm. === AgBr loading operation === # For a 5 x 4 plate place approx 3 ml 6% silver nitrate solution in the centre and at once squash it with a clean flat cover plate (preferably transparent plastic so that you can see the air bubbles are squeezed out). Leave for 3 minutes. Safelighting is not strictly necessary here but white lighting should be subdued. # Remove cover plate and immediately remove the excess silver solution on its surface by gently brushing over the plate with a soft squeegee (windscreen wiper blade). # Blow dry plate with cool air. Once dried, the plates can be stored for a short while in a cool, dry, dark location until needed. # Under safelight conditions, add 2.5 ml of dye solution per 100 ml of potassium bromide solution, add about 0.5 ml of 1% ascorbic acid solution (this is the same solution as is used in the final sensitizing bath) agitate the bath and plunge plate in while maintaining the agitation for about 2 minutes (although with softer gelatin this could be reduced to 60 seconds, otherwise unacceptable grain growth can occur. Expect to spend a little time optimising this step for your own application). This solution can be re-used a number of times, until such a point as the dye starts to come out of solution or the brightness of the resultant holograms seems to be diminished; the dye used for 532nm exposures (see above) is far more re-usable. # Rinse well under running tap water (any AgBr only on the surface can be removed by gently rubbing with ungloved finger.) Plates usually come out this bath beautifully clear under the green safe light, without any surface deposit. # Sensitizing bath step #: The plate can be immersed for 1 minute in 1% ascorbic acid solution adjusted to pH 5 using a little sodium carbonate or hydroxide. Alternatively, the well known triethanolamine pre-swelling technique can be used with the advantage of increased brightness at a shorter wavelength. (Prolonged settling period may then be necessary however to avoid creep while the exposure is being made). After exposure the plate is then developed as per the first part above. 1626e057e898453195938dfe742506c1d7c25e93 0 866 2620 2559 2014-11-11T00:28:46Z Jsfisher 1 /* Ferric Ammonium Oxalate */ wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Albumen Emulsion Plates == Filipe Alves has a go at making albumen emulsion plates. See http://www.holoforum.org/forum/viewtopic.php?t=831 Click on the '''play button''' to start the video: <html5media height="360" width="640">File:Holograms made with albumen emulsion.mp4</html5media> == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in three Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 , http://holoforum.org/forum/viewtopic.php?f=7&t=497 , http://holoforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-[[Bloom value|bloom]] pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} 94ab6aefca3e589564c7b6e9dc38766635ec4734 0 178 2621 1938 2014-11-11T00:33:51Z Jsfisher 1 wikitext text/x-wiki The backgrounds of holographers are extremely varied, as can be seen below. Without these people's tireless efforts, holography would have remained a mere laboratory curiosity, rarely to be seen elsewhere. As a result of their work, holographic techniques are more and more frequently used in science, technology, medicine, measurement and art. With the advent of lower cost lasers and recording materials, and also due to the work of the dedicated holographic popularizers among those listed below, there is a small but growing international community of amateur holographers, and it is not uncommon to have hands-on holography courses presented in elementary schools. This project is designed to collect in one place biographical info on all of the people who have made holography possible. Please feel free to post your biographies here. If you know a name but don't know the details, just add the name and we will work on getting a biography. <div style="column-count:3;-moz-column-count:3;-webkit-column-count:3"> *[[Dave Battin]] *[[Paul D. Barefoot]] *[[Kaveh Bazargan]] *[[Margaret Benyon]] *[[Steve Benton]] *[[Rudie Berkhout]] *[[Hans Bjelkhagen]] *[[Jeff Blyth]] *[[Patrick Boyd]] *[[Pam Brasier]] *[[Harriet Casdin-Silver]] *[[Greg Cherry]] *[[Melissa Crenshaw]] *[[Cross, Lloyd | Lloyd Cross]] *[[Salvador Dali]] *[[Rebecca Deem]] *[[Frank DeFreitas]] *[[Yuri Denisyuk]] *[[Georges Dyens]] *[[Phil Edelbrock]] *[[Gregg E. Favalora]] *[[Dennis Gabor]] *[[Yves Gentet]] *[[Andres Ghisays]] *[[Nancy J. Gorglione]] *[[Michael Harrison]] *[[Dr. Jeong]] T. J. *[[Frithioff Johansen]] *[[Pearl John]] *[[Colin Kaminski]] *[[John Kaufman]] *[[Roderic Lakes]] *[[Emmett Leith]] *[[Sharon McCormack]] *[[Mike Medora]] *[[Ronnie Michael]] *[[Lon Moore]] *[[Martin Mueller]] *[[Rob Munday]] *[[August Muth]] *[[Ikuo Nakamura]] *[[Anna Maria Nicholson]] *[[Caroline Palmer]] *[[Dinesh Padiyar]] *[[Joy Padiyar]] *[[John Pecora]] *[[Andrew Pepper]] *[[Hart Perry]] *[[Jerry Pethick]] *[[Nicholas Phillips]] *[[Greg Quinn]] * [[Rallison, Richard | Richard Rallison]] *[[Al Razutis]] *[[Jonathan Ross]] *[[Graham Saxby]] *[[Dan Schweitzer]] *[[Mark Segal]] *[[Walter Spierings]] *[[Anait Stephens]] *[[Fred Unterseher]] *[[Juris Upatnieks]] *[[Doris Vila]] *[[John Webster]] *[[Edward Wesly]] *[[Mieczyslaw Wolfke]] *[[Sergey Vorobyov]] *[[Sergey Zharkiy]] </div> bf71b24c57eeea666c43e4c5f92de9a75b2b3100 0 869 2622 2110 2014-11-11T00:37:13Z Jsfisher 1 /* People */ wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.gif | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Kaveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:RudieBerkhout.jpg | [[Rudie Berkhout]] File:HBjelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:HSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | [[Bernard Cole]] File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Cross, Lloyd | Lloyd Cross]] File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavalora.jpg | [[Gregg E. Favalora]] File:RDRMikef.jpg | [[Mike Foster]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:MichaelHDag.jpg | [[Michael Harrison]] File:RDRJerry83.jpg | [[Jerry Heidt]] File:RDRPosyoffice76.jpg | [[Rosemary Jackson]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:Kaufmna.jpg | [[John Kaufman]] File:RLakes.jpg | [[Roderic Lakes]] File:RDRHarry.jpg | [[Harry Knowles]] File:Leith.jpg | [[Emmett Leith]] File:GLippmann.jpg | Jonas Ferdinand [[Gabriel Lippmann]] File:RDRRick.jpg | [[Rick Lowe]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | [[Martin Mueller]] File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:FB_Rallison.jpg | [[Rallison, Richard | Richard D. Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody H Silver File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] File:RDRSpike.jpg | [[Spike Stewart]] File:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | [[Jack Worthington]] File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> 6b934788c047f53aa96dd7d3a2e50b64f8e988fe 0 869 2623 2622 2014-11-11T00:39:21Z Jsfisher 1 /* People */ wikitext text/x-wiki ===People=== <gallery> File:DBattin.jpg | [[Dave Battin]] File:PaulDBarefoot.gif | [[Paul D. Barefoot]] File:KBazargan.jpg | [[Kaveh Bazargan]] File:Benton.jpg | [[Stephen Benton]] File:Mbenyon.gif | [[Margaret Benyon]] File:RudieBerkhout.jpg | [[Rudie Berkhout]] File:HBjelkhagen.jpg | [[Hans Bjelkhagen]] File:JBlyth.jpg | [[Jeff Blyth]] File:Boyd.jpg | [[Patrick Boyd]] File:Brasier.jpg | [[Pam Brasier]] File:HSilver.jpg | [[Harriet Casdin-Silver]] File:Cherry.jpg | [[Greg Cherry]] File:Pchristie.jpg | [[Paul Christie]], founder of LitiHolo File:BCole.jpg | [[Bernard Cole]] File:Crenshaw | [[Melissa Crenshaw]] File:Lcross.jpg | [[Cross, Lloyd | Lloyd Cross]] File:Dali.jpg | [[Salvador Dali]] File:Deem.jpg | [[Rebecca Deem]] File:FDeFreitas 2.jpg | [[Frank DeFreitas]] File:FDeFreitas.jpg | [[Frank DeFreitas]] File:RDRUri.jpg | [[Yuri Denisyuk]] File:YDenisyuk2.jpg | [[Yuri Denisyuk]] File:Dyens.jpg | [[Georges Dyens]] File:Edelbrock.jpg | [[Phil Edelbrock]] File:GFavalora.jpg | [[Gregg E. Favalora]] File:RDRMikef.jpg | [[Mike Foster]] File:Gabor.gif | [[Dennis Gabor]], the father of Holography File:Gentet.jpg | [[Yves Gentet]] File:Ghisays.jpg | [[Andres Ghisays]] File:Gorglione.jpg | [[Nancy J. Gorglione]] File:MichaelHDag.jpg | [[Michael Harrison]] File:RDRJerry83.jpg | [[Jerry Heidt]] File:RDRPosyoffice76.jpg | [[Rosemary Jackson]] File:Jeong.jpg | [[Dr. Jeong T. J.]] File:Johansen.jpg | [[Frithioff Johansen]] File:PJohn.jpg | [[Pearl John]] File:Colink.jpg | [[Colin Kaminski]] File:Kaufmna.jpg | [[John Kaufman]] File:RLakes.jpg | [[Roderic Lakes]] File:RDRHarry.jpg | [[Harry Knowles]] File:Leith.jpg | [[Emmett Leith]] File:GLippmann.jpg | [[Gabriel Lippmann|Jonas Ferdinand Gabriel Lippmann]] File:RDRRick.jpg | [[Rick Lowe]] File:McCormack.jpg | [[Sharon McCormack]] File:Medora.jpg | [[Mike Medora]] File:Michael.jpg | [[Ronnie Michael]] File:Moore.jpg | [[Lon Moore]] File:Mmueller.jpg | [[Martin Mueller]] File:Munday.jpg | [[Rob Munday]] File:Muth.jpg | [[August Muth]] File:Nakamura.jpg | [[Ikuo Nakamura]] File:Nicholson.jpg | [[Anna Maria Nicholson]] File:Palmer.jpg | [[Caroline Palmer]] File:DPadiyar.jpg | [[Dinesh Padiyar]] File:JPadiyar.jpg | [[Joy Padiyar]] File:Pecora.jpg | [[John Pecora]] File:Pepper.jpg | [[Andrew Pepper]] File:Perry.jpg | [[Hart Perry]] File:Pethick.jpg | [[Jerry Pethick]] File:Phillips.jpg | [[Nicholas Phillips]] File:Quinn.jpg | [[Greg Quinn]] File:FB_Rallison.jpg | [[Rallison, Richard | Richard D. Rallison]] File:Razutis.jpg | [[Al Razutis]] File:Jross.jpg | [[Jonathan Ross]] File:Saxby.jpg | [[Graham Saxby]], author of ''Practical Holography'' File:Schweitzer.jpg | [[Dan Schweitzer]] File:Segal.jpg | [[Mark Segal]] File:HSilver.jpg | Somebody H Silver File:Spierings.jpg | [[Walter Spierings]] File:AStephens.jpg | [[Anait Stephens]] File:RDRSpike.jpg | [[Spike Stewart]] File:Unterseher.jpg | {{Fred Unterseher}] File:JUpatnieks.jpg | [[Juris Upatnieks]] File:Vila.jpg | [[Doris Vila]] File:Webster.jpg | [[John Webster]] File:Ed_Wesly.jpg | [[Edward Wesly]] File:Wolfke.jpg | [[Mieczyslaw Wolfke]] File:RDRJack84.jpg | [[Jack Worthington]] File:SVorobyov.jpg | [[Sergey Vorobyov]] File:SZharkiy.jpg | [[Sergey Zharkiy]] </gallery> 0fe10fa274cd4d9fb86effe7facbb170c2d4517c 0 176 2624 200 2014-11-11T00:46:02Z Jsfisher 1 /* Beams that Represent a Safety Hazard */ wikitext text/x-wiki ===Blocking Un-Wanted Beams and Stray Light=== Stray light becomes an ever more complicated problem as the setups contain more optics. Blocking unwanted light is a requirement of making good holograms. There are many kinds of unwanted light. ====Stray Light from Optics==== Stray light from optics comes in many forms. Painting the edges of lenses with black paint is a good start at taking care of un-wanted light. The best way to stop unwanted light is to look through the plate holder and place a black card in the way of any light getting to the plate that is not from the main beams. There are special papers available but black poster board will work in a pinch. It is important to pay special attention to the collimation mirror. ====Back-Reflections Re-Entering the Laser==== Back-reflections into a laser can be a problem, as the reflecting surface can form together with the laser cavity mirrors an unstable resonator configuration. This can lead to a chaotically fluctuating laser output with many extra unwanted [[Equipment#Longitudinal_Modes_and_Coherence_Length|longitudinal modes]] und intermittend [[Equipment#mode_jumps|mode jumps]], which can easily ruin a hologram. Particularly prone to generate such effects are [[Equipment#Spatial_Filters|spatial filters]], even more so if they use metallic and not blackened pinholes. Especially [[Types_of_Lasers#Diode_Lasersdiodes|laser diodes]] are very sensitive to even minute back reflection. The least expensive solution is to slightly mis-allign all lenses and other reflecting surfaces so their backscatter misses the laser. A more expensive solution is to pass the light through a polarizing cube beam splitter followed by a [[Equipment#Wave_Plates|1/4 wave plate]]. Any light that is reflected back towards the laser will then be deflected 90 degrees off the polarizing cube beam splitter and so won't enter the laser any more. However, this involves [[Equipment#Polarization|circularly polarized]] light and this is often not desirable in holographic applications. The most expensive solution to avoid back reflections is to use a [[Equipment#Faraday_Isolator|Faraday Isolator]]. ====Beams that Represent a Safety Hazard==== Building your optical bench either above or below eye level is the best way to keep the beam safe. Also building side above the laser plane can add a level of safety. Having a laser with adjustable power allows you to lower the power for alignment and raise the power for exposures is also possible. For very high power lasers that have no adjustable power, using a variable beam splitter to a beam dump can be used. For pulsed lasers a alignment laser can be aimed to be co-incident with the pulsed beam for alignment. If this laser is chosen as a color the film is not sensitive to, it can also be used as a safe light for loading film. ====Beams Dumps==== A beam dump allows one to dispose of the beam without any back reflections and without having it go somewhere that might fog the film. A beam dump consists of a black box with a small opening. Inside the box is a cone that diffuses the light to the sides. When designing your own make sure that the power density on the face of the cone (laser power/area) does not exceed the threshold of damage of the material of the cone. A different beam dump can be made from a glass shade 12 welding filter cut it in half lengthwise. Bounce the beam into the middle of the two plates mounted in parallel so it enters at a 45 degree angle. At each point the glass absorbs much of the light and after only a few bounces the beam is dissipated. ba2e6623827d83faa5fde1c27fc411ae422c7c83 0 1 2625 2597 2014-12-11T20:44:41Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br />'''<big>holoforum.org</big>'''<br />A place to discuss holography |} '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. {{note | The Holography Forum will soon be moving to a new location. The current site hosting the forum, http://holoforum.org, will cease operation by the end of January, 2015. Things will be relocated to a new site in the very near future, so no posts will be lost, but it will be a different location with a different URL. More information to follow.... | gotcha}} Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] d121af9c06d39a86b99ddb45cb957a137f163b46 2626 2625 2014-12-31T02:51:45Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br /> '''<big>Holoforum.org</big>'''<br />A place to discuss holography |} <big>{{note | The Holography Forum is moving. After a productive nearly half-decade at holoforum.org, the old site will dim its lights by the end January. To avoid any loss of continuity or (more importantly) content, the forum will relocate sometime on January 5, 2015 to its new home at http://holographyforum.org/forum. All the current forum's content will be carried over along with the forum archive (the "old forum") and the Lippmann Collection. Everything should look very familiar. The only speed-bump is that you will need to re-register at the new home, but that should be a simple process. January 5 is the date. It does require the coordination of three individuals' efforts to bring everything together, so an exact time is uncertain. Posts announcing the availability of the new forum will be made to Holoforum and to the Facebook group, "Holography Forum", as soon as everything is in place. | gotcha}}</big> '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 06c4f46aceb5c501e26907c8e8a17feb1cf3fc95 2627 2626 2015-01-06T03:20:13Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br /> '''<big>Holoforum.org</big>'''<br />A place to discuss holography |} <big>{{note | The Holography Forum is moving. After a productive nearly half-decade at holoforum.org, the old site will dim its lights by the end January. To avoid any loss of continuity or (more importantly) content, the forum will relocate sometime on January 5, 2015 to its new home at http://holographyforum.org/forum. All the current forum's content will be carried over along with the forum archive (the "old forum") and the Lippmann Collection. Everything should look very familiar. The only speed-bump is that you will need to re-register at the new home, but that should be a simple process. January 5 is the date. It does require the coordination of three individuals' efforts to bring everything together, so an exact time is uncertain. Posts announcing the availability of the new forum will be made to Holoforum and to the Facebook group, "Holography Forum", as soon as everything is in place. ''Update:'' Ok, well, January 5 may have been a little too ambitious. The new forum site is ready to go, but there domain name system (DNS) still needs to be updated to make the new site accessible. | gotcha}}</big> '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 115db11276af03ab6f2b5418c0996d2212b33821 2629 2627 2015-01-06T03:26:56Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holoforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://holoforum.org/forum]] <br /> '''<big>Holoforum.org</big>'''<br />A place to discuss holography |} <big>{{note | ''Update, 2015-01-05:'' Ok, well, January 5 may have been a little too ambitious. The new forum site is ready to go, but the domain name system (DNS) still needs to be updated to make the new site accessible. ''Announcement:'' The Holography Forum is moving. After a productive nearly half-decade at holoforum.org, the old site will dim its lights by the end January. To avoid any loss of continuity or (more importantly) content, the forum will relocate sometime on January 5, 2015 to its new home at http://holographyforum.org/forum. All the current forum's content will be carried over along with the forum archive (the "old forum") and the Lippmann Collection. Everything should look very familiar. The only speed-bump is that you will need to re-register at the new home, but that should be a simple process. January 5 is the date. It does require the coordination of three individuals' efforts to bring everything together, so an exact time is uncertain. Posts announcing the availability of the new forum will be made to Holoforum and to the Facebook group, "Holography Forum", as soon as everything is in place. | gotcha}}</big> '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] ea566e44f9d0b004179156e32ec7b6bd8e8f1611 2630 2629 2015-01-07T03:17:06Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org</big>'''<br />A place to discuss holography |} <big>{{note | ''Update, 2015-01-06:'' '''The new Holography Forum is up and running.''' Since updates to the Internet's domain name system (DNS) take a while to propagate, so the new link above (click on the image), may not work yet for you. It may take as long as 24 hours, but then should be just fine. ''Update, 2015-01-05:'' Ok, well, January 5 may have been a little too ambitious. The new forum site is ready to go, but the domain name system (DNS) still needs to be updated to make the new site accessible. ''Announcement:'' The Holography Forum is moving. After a productive nearly half-decade at holoforum.org, the old site will dim its lights by the end January. To avoid any loss of continuity or (more importantly) content, the forum will relocate sometime on January 5, 2015 to its new home at http://holographyforum.org/forum. All the current forum's content will be carried over along with the forum archive (the "old forum") and the Lippmann Collection. Everything should look very familiar. The only speed-bump is that you will need to re-register at the new home, but that should be a simple process. January 5 is the date. It does require the coordination of three individuals' efforts to bring everything together, so an exact time is uncertain. Posts announcing the availability of the new forum will be made to Holoforum and to the Facebook group, "Holography Forum", as soon as everything is in place. | gotcha}}</big> '''http://holoforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 36e79f9d66b914f33dfaedd5370236a5b1f874b1 2631 2630 2015-01-08T03:55:56Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org</big>'''<br />A place to discuss holography |} '''http://holographyforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 2de67657b12ea07884f7a4d62c14a77c7ccd9950 2632 2631 2015-01-16T04:19:19Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org</big>'''<br />A place to discuss holography |} '''http://holographyforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Holography Forum as moved back to its original home at holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 2b1d9ec9d0d8ff6e8686c5afaa006de81e2bd57b 2633 2632 2015-01-16T04:19:54Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org</big>'''<br />A place to discuss holography |} '''http://holographyforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * '''Holography Forum''' as moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 2529bb9c179eff77426a3743d332b3a788587c47 2634 2633 2015-01-16T04:20:20Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org</big>'''<br />A place to discuss holography |} '''http://holographyforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] e638e7b2ea89e941ac27a75099f25d0bb2542d15 2 1221 2628 2577 2015-01-06T03:23:38Z Jsfisher 1 wikitext text/x-wiki JSFisher is the username for John Fisher, the adminstrator for this Holowiki site. His qualifications for having full authority over this compendium of all things holographic are minimal. In fact, he is the self-proclaimed World's Worst Holographer. You may contact him via gmail. Remarkably, holographyforum was unclaimed as a username. The prior two sentences contain all the information needed for a human to send email to JSFisher; hopefully, spam bots will still be in the dark. Or, to be more obvious while still spam-bot resistant, '''holographyforum''' followed by an '''@''' sign followed by '''gmail.com''' is a fine address for email. 2104d167418db27cec8f9fe1bddb49d353e603a0 1 535 2635 1221 2015-05-08T01:12:54Z Colin Kaminski 2 wikitext text/x-wiki I'm inspired by the work being done here. Thank you Colin for putting up such a great wiki system! That said, the main page is a little weak right now. Especially after Technology gets broken out, this page should be a little less than line-items down a page. Perhaps groupings and more utilization of the unused real estate of the page. See my toyings on the [[sandbox]] page for some style examples which control layout (experiements to see how much I could control on a page). -Phil ------ Phil, All of the changes you have made on other pages have made things look better and made it more clear and easier to read. I trust your judgment. Please feel free to edit, move, split or rename pages at will, remember if we get somewhere we don't like we can revert. Colin ---- OK, thanks. I wasn't sure where the line was drawn for major changes/moves. I'll start digging a little deeper. -Phil ---- I will try to keep the '''''Recent changes''''' to a minimum but I was playing with changes to an existing format and wanted to embed images and do it on a linked page. JohnFP ---- What does the bold '''m''' and '''N''' stand for on the Recent changes page? JohnFP ---- '''m''' is a minor edit, meaning you checked the box. '''N''' is a new page or file addition. Don't worry about the amount of recent changes. :-) ---- OK, I put up a new main page. I'm not stuck on it, so rip it apart or whatever, it won't hurt my ego. ;') Keep in mind, that the styles define where (physically on the page) the links and text are. So, moving them into a different order does nothing. You have to tweak pixel offsets if you want BTW- The image was created using my red diode, DPSS green, and DPSS blue lasers... ha! yeah right. It's really from three seperate photos, all done with the same ancient HeNe laser. Each was turned into grayscale and colorized R,G, & B (I tried to eyeball reasonable laser colors). When layered together, the lightbulb became a very convincing white all by its self. I basicly blurred the crap out of the background, foreground, and bulb, removed 'stuck' pixels from my crappy dig camera, and added a slight embelishment from the reflected rays off the lightbulb. But, those highlights on the counter are untouched. -Phil ---- Ah, another important note is: I tried to order the topic for newbies (obviously) to the upper left, and then informational links down the left. Users in unfamiliar web pages tend to start upper left and work down. Hard core technical info goes down the right side (i.e. stuff for people who MAKE holograms). People looking for info browse the left, producers of holograms the right. It helps keep the people hitting the page for the first time in an area that they are likely to be most interested in. And, users who are familiar shouldn't have any problem looking to the right for the links they want. -Phil ---- I like the new page. I made it a little smaller to fit in one screen view for most monitors. I don't know haw to change the link colors on one page only. I know how to set them for the whole wiki. I am afraid the the blue visited link is too dark. ---- Phil that is great and amazing. I like it. John ---- I don't like the darkened image, but I total agree that the links aren't bright enough. Hummm. Overriding that style w/i the wiki is a bit of a problem. I'll ponder and play some more. Another random thought is that the 'main' page could be a static page outside of the wiki, but that might be a bit premature since things are still in major flux. At some point the main page might benefit from the added customization and control of being static. TTYL, and have a good weekend, guys! -Phil ---- I did not delete some of the older revisions of the file, I just renamed them. Play with the brighter ones. If you find one that the writing is not overwhelmed by the light bulb I am cool with having a brighter image. I like how the lasers bounce throough the lightbuld and illuminate spots on the table. ---- I am trying to change the links to a bright green for this page only. I don't quite understand this article: [http://meta.wikimedia.org/wiki/User_styles#CSS_selectors] Can we do it with this? Colin ---- I don't quite understand that page either. Can you include a css style sheet just for the main page? If so, then I think we can just create a style for bodyContent.a {color:green} (Or something like that) -Phil ---- OK, take a look at my personal page for a possible work around: http://www.holographyforum.org/HoloWiki/index.php/User:Phil_Edelbrock -Phil ---- I like that solution. Good Idea! I would prefer the words to be 532nm green. Then we could brighten up the image again. The old image was tough to view on LCD monitors as it was a little overwhelming. Colin ---- I assume you've got photoshop, right? I'll attach the PSD here. I started with a light green color, but Lippman got hard to read with the lighter image. BTW- Lippman Photography seems to be a rather odd topic to throw on the main page. It seems like it should belong to another broader category like under Technology? (edit: oops, I can't upload the file here. I emailed it to you Colin.) -Phil ---- Tweaked home page after chatting w/ Colin. Centered the light bulb (I wish it were straighter). I swapped Recording Tech and Technology, too, so they were more readable. Please email me if you want the photoshop file (phil (at) philedelbrock.com) -Phil ---- I moved the "obtaining Login" information to the footer. I also moved the What is a wiki to the about article. I then changed the page naming so it adds "A Holography Database". I think this will help us target the search engines better. ---- I reduced some wordiness on the bylines to one-liners. I think it looks and reads a bit better, but feel free to edit/revert. -Phil ---- I like the look and feel of the one liners. I would like so text for the google bots to find. Now that the text is in the image there is very little for gogle to search. Do you have any ideas? -Colin ---- Here are the original descriptions I chose them to be searchable. Perhaps we can imbed the text invisably into the main page? Welcome to the [http://www.holographyforum.org Holography Forum's] Holography Wiki. The goal of this wiki is to create a knowledge base for the holographic arts. It is divided into sections as follows: *'''[[Holography for Beginners]].''' A FAQ for beginning holographers. *'''[[Holography Technology]].''' The hardware and setups for making holograms. *'''[[Hologram Recording Materials]].''' *'''[[Holography Theory]].''' The Mathematics of Holography. *'''[[History of Holography]].''' A project to document the people and events before we grow old and forget how exciting this last 60 years has been. *'''[[Holography Safety]].''' Knowledge and practices. *'''[[Biographies of Holographers]].''' The people who have made the magical world of holography posible. *'''[[Holography Links]].''' The World Wide Web for Holography. *'''[[Holography Glossary]].''' A Glossary of holography releated terms. ---- Ok, that still needs lots of work, but I have to run to work. ---- Yeah, they could just be under the image. Google will see them and others won't. (edit: lol, I was thinking under the image literally as a style layer underneith, but a text summary at the bottom of the page works great, too. Probably better since we can see and edit it.) -Phil ---- I revised the footer nav. Colin, if you have the psd file that made the current image handy, center up the light bulb (say 10 pixels to the left, from eyeballing it). That will help make Lippmann a little easier to read and center up the image. This is really great stuff on the wiki. I'm glad to be a part of it, I just wish I had more time/money to help. ;') -Phil ---- I made a new logo for the holography forum link in the footer. It is much sharper. I tried to move the bulb around but I am not skilled enough. I was creating problems on the right edge and then I was loosing some of the laser light bouncing down from the bulb under some of the words. :-( -Colin Feel free to clean up the Hologram Recording Materials section on the main page. I tried to add (& Chemistry) which is in the code but could not get it to show up on the Main Page. So I modified the description underneath. I believe we need this as it is hard to find where chemistry is discussed on the main page. JohnFP Never mind. I found that what I tried to alter in the titles ended up breaking the links, so I just added to the discription of each on the main page to include chemistry. JohnFP --------------------------------------------------------------------------------- Do you think we should have a "Suppliers" section? I was thinking of purchasing some of those magnetic mount bases and could not find the thread on the forum. I know as time goes on it may become outdated but it would be a good reference for things like Pinholes, bases, chemicals etc.. John Pecora --------------------------------------------------------------------------------------------- I wonder if we want a manuals section. I have found that to be the hardest thing to locate when a used piece of equipment is purchased. Augie sent me a copy of his for my Ion laser. And I was reading a laser forum and someone else was looking for that same manual, whick I will copy for him. Are their any legalities associated with posting manuals here? John Pecora --------------------------------------------- If we have a disclaimer that we contacted (a person's name) and recieved permission to publish it here. This is not the easiest thing to aquire. Without it I would advise you to make a section on your own site and post a link in the links section. Oh, yeah the supplier for magnetic baes is Enco.- ---------------------------------------------------------------------------------------------- What happened to all the developing and processing formulas? Do they survive? Colin abd874fc969c7a071df84bc52ee5d00b69f66367 2636 2635 2015-05-08T01:20:30Z Colin Kaminski 2 wikitext text/x-wiki I'm inspired by the work being done here. Thank you Colin for putting up such a great wiki system! That said, the main page is a little weak right now. Especially after Technology gets broken out, this page should be a little less than line-items down a page. Perhaps groupings and more utilization of the unused real estate of the page. See my toyings on the [[sandbox]] page for some style examples which control layout (experiements to see how much I could control on a page). -Phil ------ Phil, All of the changes you have made on other pages have made things look better and made it more clear and easier to read. I trust your judgment. Please feel free to edit, move, split or rename pages at will, remember if we get somewhere we don't like we can revert. Colin ---- OK, thanks. I wasn't sure where the line was drawn for major changes/moves. I'll start digging a little deeper. -Phil ---- I will try to keep the '''''Recent changes''''' to a minimum but I was playing with changes to an existing format and wanted to embed images and do it on a linked page. JohnFP ---- What does the bold '''m''' and '''N''' stand for on the Recent changes page? JohnFP ---- '''m''' is a minor edit, meaning you checked the box. '''N''' is a new page or file addition. Don't worry about the amount of recent changes. :-) ---- OK, I put up a new main page. I'm not stuck on it, so rip it apart or whatever, it won't hurt my ego. ;') Keep in mind, that the styles define where (physically on the page) the links and text are. So, moving them into a different order does nothing. You have to tweak pixel offsets if you want BTW- The image was created using my red diode, DPSS green, and DPSS blue lasers... ha! yeah right. It's really from three seperate photos, all done with the same ancient HeNe laser. Each was turned into grayscale and colorized R,G, & B (I tried to eyeball reasonable laser colors). When layered together, the lightbulb became a very convincing white all by its self. I basicly blurred the crap out of the background, foreground, and bulb, removed 'stuck' pixels from my crappy dig camera, and added a slight embelishment from the reflected rays off the lightbulb. But, those highlights on the counter are untouched. -Phil ---- Ah, another important note is: I tried to order the topic for newbies (obviously) to the upper left, and then informational links down the left. Users in unfamiliar web pages tend to start upper left and work down. Hard core technical info goes down the right side (i.e. stuff for people who MAKE holograms). People looking for info browse the left, producers of holograms the right. It helps keep the people hitting the page for the first time in an area that they are likely to be most interested in. And, users who are familiar shouldn't have any problem looking to the right for the links they want. -Phil ---- I like the new page. I made it a little smaller to fit in one screen view for most monitors. I don't know haw to change the link colors on one page only. I know how to set them for the whole wiki. I am afraid the the blue visited link is too dark. ---- Phil that is great and amazing. I like it. John ---- I don't like the darkened image, but I total agree that the links aren't bright enough. Hummm. Overriding that style w/i the wiki is a bit of a problem. I'll ponder and play some more. Another random thought is that the 'main' page could be a static page outside of the wiki, but that might be a bit premature since things are still in major flux. At some point the main page might benefit from the added customization and control of being static. TTYL, and have a good weekend, guys! -Phil ---- I did not delete some of the older revisions of the file, I just renamed them. Play with the brighter ones. If you find one that the writing is not overwhelmed by the light bulb I am cool with having a brighter image. I like how the lasers bounce throough the lightbuld and illuminate spots on the table. ---- I am trying to change the links to a bright green for this page only. I don't quite understand this article: [http://meta.wikimedia.org/wiki/User_styles#CSS_selectors] Can we do it with this? Colin ---- I don't quite understand that page either. Can you include a css style sheet just for the main page? If so, then I think we can just create a style for bodyContent.a {color:green} (Or something like that) -Phil ---- OK, take a look at my personal page for a possible work around: http://www.holographyforum.org/HoloWiki/index.php/User:Phil_Edelbrock -Phil ---- I like that solution. Good Idea! I would prefer the words to be 532nm green. Then we could brighten up the image again. The old image was tough to view on LCD monitors as it was a little overwhelming. Colin ---- I assume you've got photoshop, right? I'll attach the PSD here. I started with a light green color, but Lippman got hard to read with the lighter image. BTW- Lippman Photography seems to be a rather odd topic to throw on the main page. It seems like it should belong to another broader category like under Technology? (edit: oops, I can't upload the file here. I emailed it to you Colin.) -Phil ---- Tweaked home page after chatting w/ Colin. Centered the light bulb (I wish it were straighter). I swapped Recording Tech and Technology, too, so they were more readable. Please email me if you want the photoshop file (phil (at) philedelbrock.com) -Phil ---- I moved the "obtaining Login" information to the footer. I also moved the What is a wiki to the about article. I then changed the page naming so it adds "A Holography Database". I think this will help us target the search engines better. ---- I reduced some wordiness on the bylines to one-liners. I think it looks and reads a bit better, but feel free to edit/revert. -Phil ---- I like the look and feel of the one liners. I would like so text for the google bots to find. Now that the text is in the image there is very little for gogle to search. Do you have any ideas? -Colin ---- Here are the original descriptions I chose them to be searchable. Perhaps we can imbed the text invisably into the main page? Welcome to the [http://www.holographyforum.org Holography Forum's] Holography Wiki. The goal of this wiki is to create a knowledge base for the holographic arts. It is divided into sections as follows: *'''[[Holography for Beginners]].''' A FAQ for beginning holographers. *'''[[Holography Technology]].''' The hardware and setups for making holograms. *'''[[Hologram Recording Materials]].''' *'''[[Holography Theory]].''' The Mathematics of Holography. *'''[[History of Holography]].''' A project to document the people and events before we grow old and forget how exciting this last 60 years has been. *'''[[Holography Safety]].''' Knowledge and practices. *'''[[Biographies of Holographers]].''' The people who have made the magical world of holography posible. *'''[[Holography Links]].''' The World Wide Web for Holography. *'''[[Holography Glossary]].''' A Glossary of holography releated terms. ---- Ok, that still needs lots of work, but I have to run to work. ---- Yeah, they could just be under the image. Google will see them and others won't. (edit: lol, I was thinking under the image literally as a style layer underneith, but a text summary at the bottom of the page works great, too. Probably better since we can see and edit it.) -Phil ---- I revised the footer nav. Colin, if you have the psd file that made the current image handy, center up the light bulb (say 10 pixels to the left, from eyeballing it). That will help make Lippmann a little easier to read and center up the image. This is really great stuff on the wiki. I'm glad to be a part of it, I just wish I had more time/money to help. ;') -Phil ---- I made a new logo for the holography forum link in the footer. It is much sharper. I tried to move the bulb around but I am not skilled enough. I was creating problems on the right edge and then I was loosing some of the laser light bouncing down from the bulb under some of the words. :-( -Colin Feel free to clean up the Hologram Recording Materials section on the main page. I tried to add (& Chemistry) which is in the code but could not get it to show up on the Main Page. So I modified the description underneath. I believe we need this as it is hard to find where chemistry is discussed on the main page. JohnFP Never mind. I found that what I tried to alter in the titles ended up breaking the links, so I just added to the discription of each on the main page to include chemistry. JohnFP --------------------------------------------------------------------------------- Do you think we should have a "Suppliers" section? I was thinking of purchasing some of those magnetic mount bases and could not find the thread on the forum. I know as time goes on it may become outdated but it would be a good reference for things like Pinholes, bases, chemicals etc.. John Pecora --------------------------------------------------------------------------------------------- I wonder if we want a manuals section. I have found that to be the hardest thing to locate when a used piece of equipment is purchased. Augie sent me a copy of his for my Ion laser. And I was reading a laser forum and someone else was looking for that same manual, whick I will copy for him. Are their any legalities associated with posting manuals here? John Pecora --------------------------------------------- If we have a disclaimer that we contacted (a person's name) and recieved permission to publish it here. This is not the easiest thing to aquire. Without it I would advise you to make a section on your own site and post a link in the links section. Oh, yeah the supplier for magnetic baes is Enco.- ---------------------------------------------------------------------------------------------- What happened to all the developing and processing formulas? Do they survive? Colin Never Mind, I found it hee: http://holowiki.nss.rpi.edu/wiki/Ewesly_/_Holographic_Formulae 1b8261fee627bdbf1c1844c4f4427d69826ac01e 1 1231 2637 2015-05-08T01:26:56Z Colin Kaminski 2 Created page with "My Laptop that had the equation editing software on it is long gone. Perhaps we can finis up the equations for Ed's great work here. Colin" wikitext text/x-wiki My Laptop that had the equation editing software on it is long gone. Perhaps we can finis up the equations for Ed's great work here. 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519c08da88276b2f47bc6fb30637d415fd0d804e 6 1280 2686 2015-07-19T04:07:02Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1281 2687 2015-07-19T04:07:29Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1282 2688 2015-07-19T04:08:04Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1283 2689 2015-07-19T04:08:41Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1284 2690 2015-07-19T04:10:18Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1285 2691 2015-07-19T04:11:41Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1286 2692 2015-07-19T04:12:08Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 1287 2693 2015-07-19T11:53:47Z Jsfisher 1 Created page with "<big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> <p>The list below is a copy from the <a href="http://isdh2015.ifmo.ru/docs/ISDH2015_program.pd..." wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> <p>The list below is a copy from the <a href="http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf">final program</a> available at <a href="http://isdh2015.ifmo.ru">ISDH 2015 web page</a>. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation.</p> <p>This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i></p> <h2>Plenary Session</h2> ;HOLOGRAPHY: CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) <h3>DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE?</h3> <p>by Ian M. Lancaster (UK) (invited)</p> <h2>Session 1. History, Culture, and Education</h2> <h3><a href="ISDH2015Pombo.pdf">HOLOGRAPHY FOR ALL</a></h3> <p>by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal)</p> <h3>ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION</h3> <p>by Leonid V. Tanin (Belarus) (invited)</p> <h3><a href="ISDH2015Gulyaev.pdf">IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY</a></h3> <p>by Sergey Gulyaev (Russia)</p> <h3><a href="ISDH2015Ross.pdf">COLLECTING AND EXHIBITING HOLOGRAMS</a></h3> <p>by Jonathan Ross (UK)</p> <h3>OPAL: THE NATURAL PHOTONIC CRYSTAL</h3> <p>by Francesco Mazzero</p> <h2>Session 2. Art Concepts & Techniques</h2> <h3>REFLECTIVE HOLOGRAPHY</h3> <p>by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal)</p> <h3>RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY</h3> <p>by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK)</p> <h3>MERGING THE MATERIAL WITH THE IMMATERIAL</h3> <p>by Richard Bruck (USA)</p> <h3>COMMUNICATING IN 3D VISIBLE LANGUAGE</h3> <p>by Yin-Ren Chang, Martin Richardson (UK)</p> <h3>HOLOGRAPHY AS AN ARCHITECTURAL DECORATION</h3> <p>by Setsuko Ishii (Japan)</p> <h3><a href="ISDH2015John.pdf">AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?</a></h3> <p>by Pearl John (UK)</p> <h3><a href="ISDH2015Vorzobova_Bulgakova.pdf">HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS</a></h3> <p>by Nadezda Vorzobova, Vera Bulgakova (Russia)</p> <h3>WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA</h3> <p>by John August Muth (USA)</p> <h3>HOLOGRAPHY IN DESIGN</h3> <p>by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea)</p> <h3><a href="ISDH2015Richardson.pdf">AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM</a></h3> <p>by Martin Richardson, Vivian Suresh Kumar Amos (UK)</p> <h3>HOLOGRAMS IN CAVES</h3> <p>by Julio Ruiz, Luis Roves (Spain)</p> <h3><a href="ISDH2015Khan.pdf">MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY</a></h3> <p>by Javid Khan (UK)</p> <h3>CREATING STEREOGRAMS ON AN iPhone</h3> <p>by Patrick Boyd (UK)</p> <h3><a href="ISDH2015Janardo.pdf">ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS</a></h3> <p>by Nuno Miguel José Janardo (Portugal)</p> <h2>Session 3. Recording Materials & Processing</h2> <h3><a href="ISDH2015Andreeva.pdf">DISPLAY HOLOGRAPHY AND NANOPLASMONICS</a></h3> <p>by Olga Andreeva (Russia)</p> <h3><a href="ISDH2015Banyasz.pdf">EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE</a></h3> <p>by István Bányász (Hungary)</p> <h3><a href="ISDH2015Ganzherli.pdf">HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS</a></h3> <p>by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia)</p> <h3><a href="ISDH2015Kutanov.pdf">DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM</a></h3> <p>by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan)</p> <h3><a href="ISDH2015Vorzobova_Ryabova.pdf">CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING</a></h3> <p>by Nadezda Vorzobova, Roze Ryabova (Russia)</p> <h3><a href="ISDH2015Gentet.pdf">RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's</a></h3> <p>by Yves Gentet (France)</p> <h2>Session 4. Electronic, Digital & CGH</h2> <h3><a href="ISDH2015Brotherton-Ratcliffe.pdf">A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS</a></h3> <p>by David Brotherton-Ratcliffe (UK) (invited)</p> <h3><a href="ISDH2015Page.pdf">VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES</a></h3> <p>by Michael Page (Canada) (invited)</p> <h3><a href="ISDH2015Bove.pdf">PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS</a></h3> <p>by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA)</p> <h3><a href="ISDH2015Cheng.pdf">IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE</a></h3> <p>by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan)</p> <h3><a href="ISDH2015Jia.pdf">A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY</a></h3> <p>by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China)</p> <h3><a href="ISDH2015Morozov.pdf">INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER</a></h3> <p>by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia)</p> <h3><a href="ISDH2015Kang.pdf">COLOR HOLOGRAPHIC WAVEFRONT PRINTER</a></h3> <p>by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea)</p> <h3><a href="ISDH2015Kazempourradi.pdf">HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS</a></h3> <p>by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey)</p> <h3><a href="ISDH2015Khan2.pdf">A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS</a></h3> <p>by Javid Khan (UK)</p> <h3><a href="ISDH2015Kim.pdf">FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD</a></h3> <p>by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea)</p> <h3><a href="ISDH2015Kolyuchkin.pdf">THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS</a></h3> <p>by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia)</p> <h3><a href="ISDH2015Zlokazov.pdf">COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION</a></h3> <p>by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia)</p> <h3><a href="ISDH2015Paraschou.pdf">EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION</a></h3> <p>by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece)</p> <h3><a href="ISDH2015Lobaz.pdf">DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS</a></h3> <p>by Petr Lobaz (Czech Republic)</p> <h3><a href="ISDH2015Matsushima.pdf">NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY</a></h3> <p>by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan)</p> <h3><a href="ISDH2015Sakamoto.pdf">FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL</a></h3> <p>by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan)</p> <h3><a href="ISDH2015Yoshikawa.pdf">IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM</a></h3> <p>by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan)</p> <h3><a href="ISDH2015Zhang.pdf">COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM</a></h3> <p>by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China)</p> <h3><a href="ISDH2015Zhao.pdf">DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY</a></h3> <p>by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China)</p> <h2>Session 5. Technical Applications</h2> <h3><a href="ISDH2015GaoHongyue.pdf">REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV</a></h3> <p>by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited)</p> <h3><a href="ISDH2015Parker.pdf">HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY"</a></h3> <p>by William Parker, Julie Parker (USA) (invited)</p> <h3><a href="ISDH2015Rastogi.pdf">ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY</a></h3> <p>by Pramod Rastogi (Switzerland) (invited)</p> <h3>HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS</h3> <p>by Turukhano B., Turukhano N. (Russia)</p> <h3><a href="ISDH2015Wesly.pdf">PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY</a></h3> <p>by Ed Wesly (USA)</p> <h3><a href="ISDH2015Chiu.pdf">HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE</a></h3> <p>by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan)</p> <h3>IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS</h3> <p>by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan)</p> <h3><a href="ISDH2015Tornari.pdf">HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART</a></h3> <p>by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece)</p> <h3><a href="ISDH2015Dyomin.pdf">AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES</a></h3> <p>by Victor Dyomin, Denis Kamenev (Russia)</p> <h3><a href="ISDH2015Burunkova.pdf">GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING</a></h3> <p>by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia)</p> <h3><a href="ISDH2015Osanlou.pdf">HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES</a></h3> <p>by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK)</p> <h3><a href="ISDH2015Ryu.pdf">OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES</a></h3> <p>by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia)</p> <h3><a href="ISDH2015Druzhin.pdf">HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY</a></h3> <p>by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia)</p> <h3><a href="ISDH2015Zherdev.pdf">PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES</a></h3> <p>by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia)</p> <h3><a href="ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS</a></h3> <p>by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China)</p> <h2>Session 6. Color Holography</h2> <h3><a href="ISDH2015Bjelkhagen.pdf">ULTRA-REALISTIC IMAGING AND OPTOCLONES</a></h3> <p>by Hans Bjelkhagen (UK)</p> <h3>ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY</h3> <p>by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland)</p> <h3><a href="ISDH2015Lembessis.pdf">THE "F" ADVENTURE</a></h3> <p>by Alkis Lembessis, Andreas Sarakinos (Greece)</p> <h3><a href="ISDH2015Odinokov.pdf">EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION</a></h3> <p>by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia)</p> <h3>METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA</h3> <p>by Natalith Palacios Ortega, Daniel Velasquez (Colombia)</p> <h3><a href="ISDH2015Shevtsov_Gentet.pdf">20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY</a></h3> <p>by Michael Shevtsov, Yves Gentet (Russia)</p> <h3><a href="ISDH2015Sarakinos.pdf">IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS</a></h3> <p>by Andreas Sarakinos, Alkis Lembessis (Greece)</p> <h3><a href="ISDH2015Stock.pdf">NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY</a></h3> <p>by Michelle Stock, Peter Andersen, Peter Skovgaard (USA)</p> <h3><a href="ISDH2015Shevtsov.pdf">MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION</a></h3> <p>by Michael Shevtsov (Russia)</p> <h3><a href="ISDH2015Yuan.pdf">MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS</a></h3> <p>by Quan Yuan (China)</p> <h2>Session 7. The Business of Holography</h2> <h3><a href="ISDH2015Fan.pdf">DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER</a></h3> <p>by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited)</p> <h3>STRIVING TO MAKE A LIVING WITH 3D IMAGES: QUITE A CHALLENGE...</h3> <p>by Pascal Gauchet (France)</p> <h3><a href="ISDH2015Beryozkina.pdf">SLAVICH HOLOGRAPHIC MATERIALS</a></h3> <p>by Juliay Beryozkina (Russia)</p> <h3><a href="ISDH2015Souparis1.pdf">FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES</a></h3> <p>by Hugues Souparis (France)</p> <h3><a href="ISDH2015Souparis2.pdf">THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART</a></h3> <p>by Hugues Souparis (France)</p> <h3>REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL</h3> <p>by Tim Sandford</p> <h3>SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS</h3> <p>by Leonid Tanin</p> <h2>Youth Session, Workshop</h2> <h3>RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD</h3> <p>by Nataliy Andreeva (Russia)</p> <h3><a href="ISDH2015Escarguel.pdf">UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT</a></h3> <p>by Alexandre Escarguel (France)</p> <h3>DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON</h3> <p>by Victor Dyomin (Russia)</p> <h3>HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES</h3> <p>by Boris Manukhin (Russia)</p> <h3>RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT</h3> <p>by Paramonov Alexandr (Russia)</p> <h3>SIMULATION OF WAVEFRONT PROPAGATION</h3> <p>by Nikolay Petrov (Russia)</p> 5c2da2e9784ef635ac9b1f2c33480c5ce603eea2 2694 2693 2015-07-19T12:04:49Z Jsfisher 1 wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the <a href="http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf">final program</a> available at <a href="http://isdh2015.ifmo.ru">ISDH 2015 web page</a>. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY: CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == Session 1. History, Culture, and Education == [[ media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL ]] by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION by Leonid V. Tanin (Belarus) (invited) [[ media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY ]] by Sergey Gulyaev (Russia) [[ media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] by Jonathan Ross (UK) OPAL: THE NATURAL PHOTONIC CRYSTAL by Francesco Mazzero == Session 2. Art Concepts & Techniques == <h3>REFLECTIVE HOLOGRAPHY</h3> <p>by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal)</p> <h3>RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY</h3> <p>by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK)</p> <h3>MERGING THE MATERIAL WITH THE IMMATERIAL</h3> <p>by Richard Bruck (USA)</p> <h3>COMMUNICATING IN 3D VISIBLE LANGUAGE</h3> <p>by Yin-Ren Chang, Martin Richardson (UK)</p> <h3>HOLOGRAPHY AS AN ARCHITECTURAL DECORATION</h3> <p>by Setsuko Ishii (Japan)</p> <h3><a href="ISDH2015John.pdf">AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?</a></h3> <p>by Pearl John (UK)</p> <h3><a href="ISDH2015Vorzobova_Bulgakova.pdf">HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS</a></h3> <p>by Nadezda Vorzobova, Vera Bulgakova (Russia)</p> <h3>WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA</h3> <p>by John August Muth (USA)</p> <h3>HOLOGRAPHY IN DESIGN</h3> <p>by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea)</p> <h3><a href="ISDH2015Richardson.pdf">AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM</a></h3> <p>by Martin Richardson, Vivian Suresh Kumar Amos (UK)</p> <h3>HOLOGRAMS IN CAVES</h3> <p>by Julio Ruiz, Luis Roves (Spain)</p> <h3><a href="ISDH2015Khan.pdf">MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY</a></h3> <p>by Javid Khan (UK)</p> <h3>CREATING STEREOGRAMS ON AN iPhone</h3> <p>by Patrick Boyd (UK)</p> <h3><a href="ISDH2015Janardo.pdf">ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS</a></h3> <p>by Nuno Miguel José Janardo (Portugal)</p> <h2>Session 3. Recording Materials & Processing</h2> <h3><a href="ISDH2015Andreeva.pdf">DISPLAY HOLOGRAPHY AND NANOPLASMONICS</a></h3> <p>by Olga Andreeva (Russia)</p> <h3><a href="ISDH2015Banyasz.pdf">EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE</a></h3> <p>by István Bányász (Hungary)</p> <h3><a href="ISDH2015Ganzherli.pdf">HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS</a></h3> <p>by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia)</p> <h3><a href="ISDH2015Kutanov.pdf">DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM</a></h3> <p>by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan)</p> <h3><a href="ISDH2015Vorzobova_Ryabova.pdf">CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING</a></h3> <p>by Nadezda Vorzobova, Roze Ryabova (Russia)</p> <h3><a href="ISDH2015Gentet.pdf">RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's</a></h3> <p>by Yves Gentet (France)</p> <h2>Session 4. Electronic, Digital & CGH</h2> <h3><a href="ISDH2015Brotherton-Ratcliffe.pdf">A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS</a></h3> <p>by David Brotherton-Ratcliffe (UK) (invited)</p> <h3><a href="ISDH2015Page.pdf">VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES</a></h3> <p>by Michael Page (Canada) (invited)</p> <h3><a href="ISDH2015Bove.pdf">PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS</a></h3> <p>by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA)</p> <h3><a href="ISDH2015Cheng.pdf">IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE</a></h3> <p>by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan)</p> <h3><a href="ISDH2015Jia.pdf">A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY</a></h3> <p>by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China)</p> <h3><a href="ISDH2015Morozov.pdf">INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER</a></h3> <p>by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia)</p> <h3><a href="ISDH2015Kang.pdf">COLOR HOLOGRAPHIC WAVEFRONT PRINTER</a></h3> <p>by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea)</p> <h3><a href="ISDH2015Kazempourradi.pdf">HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS</a></h3> <p>by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey)</p> <h3><a href="ISDH2015Khan2.pdf">A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS</a></h3> <p>by Javid Khan (UK)</p> <h3><a href="ISDH2015Kim.pdf">FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD</a></h3> <p>by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea)</p> <h3><a href="ISDH2015Kolyuchkin.pdf">THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS</a></h3> <p>by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia)</p> <h3><a href="ISDH2015Zlokazov.pdf">COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION</a></h3> <p>by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia)</p> <h3><a href="ISDH2015Paraschou.pdf">EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION</a></h3> <p>by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece)</p> <h3><a href="ISDH2015Lobaz.pdf">DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS</a></h3> <p>by Petr Lobaz (Czech Republic)</p> <h3><a href="ISDH2015Matsushima.pdf">NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY</a></h3> <p>by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan)</p> <h3><a href="ISDH2015Sakamoto.pdf">FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL</a></h3> <p>by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan)</p> <h3><a href="ISDH2015Yoshikawa.pdf">IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM</a></h3> <p>by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan)</p> <h3><a href="ISDH2015Zhang.pdf">COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM</a></h3> <p>by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China)</p> <h3><a href="ISDH2015Zhao.pdf">DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY</a></h3> <p>by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China)</p> <h2>Session 5. Technical Applications</h2> <h3><a href="ISDH2015GaoHongyue.pdf">REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV</a></h3> <p>by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited)</p> <h3><a href="ISDH2015Parker.pdf">HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY"</a></h3> <p>by William Parker, Julie Parker (USA) (invited)</p> <h3><a href="ISDH2015Rastogi.pdf">ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY</a></h3> <p>by Pramod Rastogi (Switzerland) (invited)</p> <h3>HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS</h3> <p>by Turukhano B., Turukhano N. (Russia)</p> <h3><a href="ISDH2015Wesly.pdf">PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY</a></h3> <p>by Ed Wesly (USA)</p> <h3><a href="ISDH2015Chiu.pdf">HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE</a></h3> <p>by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan)</p> <h3>IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS</h3> <p>by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan)</p> <h3><a href="ISDH2015Tornari.pdf">HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART</a></h3> <p>by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece)</p> <h3><a href="ISDH2015Dyomin.pdf">AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES</a></h3> <p>by Victor Dyomin, Denis Kamenev (Russia)</p> <h3><a href="ISDH2015Burunkova.pdf">GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING</a></h3> <p>by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia)</p> <h3><a href="ISDH2015Osanlou.pdf">HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES</a></h3> <p>by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK)</p> <h3><a href="ISDH2015Ryu.pdf">OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES</a></h3> <p>by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia)</p> <h3><a href="ISDH2015Druzhin.pdf">HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY</a></h3> <p>by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia)</p> <h3><a href="ISDH2015Zherdev.pdf">PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES</a></h3> <p>by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia)</p> <h3><a href="ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS</a></h3> <p>by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China)</p> <h2>Session 6. Color Holography</h2> <h3><a href="ISDH2015Bjelkhagen.pdf">ULTRA-REALISTIC IMAGING AND OPTOCLONES</a></h3> <p>by Hans Bjelkhagen (UK)</p> <h3>ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY</h3> <p>by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland)</p> <h3><a href="ISDH2015Lembessis.pdf">THE "F" ADVENTURE</a></h3> <p>by Alkis Lembessis, Andreas Sarakinos (Greece)</p> <h3><a href="ISDH2015Odinokov.pdf">EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION</a></h3> <p>by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia)</p> <h3>METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA</h3> <p>by Natalith Palacios Ortega, Daniel Velasquez (Colombia)</p> <h3><a href="ISDH2015Shevtsov_Gentet.pdf">20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY</a></h3> <p>by Michael Shevtsov, Yves Gentet (Russia)</p> <h3><a href="ISDH2015Sarakinos.pdf">IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS</a></h3> <p>by Andreas Sarakinos, Alkis Lembessis (Greece)</p> <h3><a href="ISDH2015Stock.pdf">NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY</a></h3> <p>by Michelle Stock, Peter Andersen, Peter Skovgaard (USA)</p> <h3><a href="ISDH2015Shevtsov.pdf">MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION</a></h3> <p>by Michael Shevtsov (Russia)</p> <h3><a href="ISDH2015Yuan.pdf">MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS</a></h3> <p>by Quan Yuan (China)</p> <h2>Session 7. The Business of Holography</h2> <h3><a href="ISDH2015Fan.pdf">DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER</a></h3> <p>by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited)</p> <h3>STRIVING TO MAKE A LIVING WITH 3D IMAGES: QUITE A CHALLENGE...</h3> <p>by Pascal Gauchet (France)</p> <h3><a href="ISDH2015Beryozkina.pdf">SLAVICH HOLOGRAPHIC MATERIALS</a></h3> <p>by Juliay Beryozkina (Russia)</p> <h3><a href="ISDH2015Souparis1.pdf">FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES</a></h3> <p>by Hugues Souparis (France)</p> <h3><a href="ISDH2015Souparis2.pdf">THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART</a></h3> <p>by Hugues Souparis (France)</p> <h3>REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL</h3> <p>by Tim Sandford</p> <h3>SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS</h3> <p>by Leonid Tanin</p> <h2>Youth Session, Workshop</h2> <h3>RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD</h3> <p>by Nataliy Andreeva (Russia)</p> <h3><a href="ISDH2015Escarguel.pdf">UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT</a></h3> <p>by Alexandre Escarguel (France)</p> <h3>DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON</h3> <p>by Victor Dyomin (Russia)</p> <h3>HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES</h3> <p>by Boris Manukhin (Russia)</p> <h3>RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT</h3> <p>by Paramonov Alexandr (Russia)</p> <h3>SIMULATION OF WAVEFRONT PROPAGATION</h3> <p>by Nikolay Petrov (Russia)</p> 7ebbb66733d77573b31de4d74add9149f7042697 2695 2694 2015-07-19T12:09:27Z Jsfisher 1 /* Session 1. History, Culture, and Education */ wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the <a href="http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf">final program</a> available at <a href="http://isdh2015.ifmo.ru">ISDH 2015 web page</a>. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY: CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[ media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL ]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[ media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY ]] : by Sergey Gulyaev (Russia) ;[[ media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Session 2. Art Concepts & Techniques == <h3>REFLECTIVE HOLOGRAPHY</h3> <p>by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal)</p> <h3>RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY</h3> <p>by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK)</p> <h3>MERGING THE MATERIAL WITH THE IMMATERIAL</h3> <p>by Richard Bruck (USA)</p> <h3>COMMUNICATING IN 3D VISIBLE LANGUAGE</h3> <p>by Yin-Ren Chang, Martin Richardson (UK)</p> <h3>HOLOGRAPHY AS AN ARCHITECTURAL DECORATION</h3> <p>by Setsuko Ishii (Japan)</p> <h3><a href="ISDH2015John.pdf">AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?</a></h3> <p>by Pearl John (UK)</p> <h3><a href="ISDH2015Vorzobova_Bulgakova.pdf">HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS</a></h3> <p>by Nadezda Vorzobova, Vera Bulgakova (Russia)</p> <h3>WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA</h3> <p>by John August Muth (USA)</p> <h3>HOLOGRAPHY IN DESIGN</h3> <p>by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea)</p> <h3><a href="ISDH2015Richardson.pdf">AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM</a></h3> <p>by Martin Richardson, Vivian Suresh Kumar Amos (UK)</p> <h3>HOLOGRAMS IN CAVES</h3> <p>by Julio Ruiz, Luis Roves (Spain)</p> <h3><a href="ISDH2015Khan.pdf">MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY</a></h3> <p>by Javid Khan (UK)</p> <h3>CREATING STEREOGRAMS ON AN iPhone</h3> <p>by Patrick Boyd (UK)</p> <h3><a href="ISDH2015Janardo.pdf">ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS</a></h3> <p>by Nuno Miguel José Janardo (Portugal)</p> <h2>Session 3. Recording Materials & Processing</h2> <h3><a href="ISDH2015Andreeva.pdf">DISPLAY HOLOGRAPHY AND NANOPLASMONICS</a></h3> <p>by Olga Andreeva (Russia)</p> <h3><a href="ISDH2015Banyasz.pdf">EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE</a></h3> <p>by István Bányász (Hungary)</p> <h3><a href="ISDH2015Ganzherli.pdf">HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS</a></h3> <p>by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia)</p> <h3><a href="ISDH2015Kutanov.pdf">DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM</a></h3> <p>by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan)</p> <h3><a href="ISDH2015Vorzobova_Ryabova.pdf">CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING</a></h3> <p>by Nadezda Vorzobova, Roze Ryabova (Russia)</p> <h3><a href="ISDH2015Gentet.pdf">RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's</a></h3> <p>by Yves Gentet (France)</p> <h2>Session 4. Electronic, Digital & CGH</h2> <h3><a href="ISDH2015Brotherton-Ratcliffe.pdf">A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS</a></h3> <p>by David Brotherton-Ratcliffe (UK) (invited)</p> <h3><a href="ISDH2015Page.pdf">VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES</a></h3> <p>by Michael Page (Canada) (invited)</p> <h3><a href="ISDH2015Bove.pdf">PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS</a></h3> <p>by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA)</p> <h3><a href="ISDH2015Cheng.pdf">IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE</a></h3> <p>by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan)</p> <h3><a href="ISDH2015Jia.pdf">A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY</a></h3> <p>by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China)</p> <h3><a href="ISDH2015Morozov.pdf">INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER</a></h3> <p>by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia)</p> <h3><a href="ISDH2015Kang.pdf">COLOR HOLOGRAPHIC WAVEFRONT PRINTER</a></h3> <p>by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea)</p> <h3><a href="ISDH2015Kazempourradi.pdf">HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS</a></h3> <p>by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey)</p> <h3><a href="ISDH2015Khan2.pdf">A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS</a></h3> <p>by Javid Khan (UK)</p> <h3><a href="ISDH2015Kim.pdf">FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD</a></h3> <p>by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea)</p> <h3><a href="ISDH2015Kolyuchkin.pdf">THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS</a></h3> <p>by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia)</p> <h3><a href="ISDH2015Zlokazov.pdf">COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION</a></h3> <p>by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia)</p> <h3><a href="ISDH2015Paraschou.pdf">EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION</a></h3> <p>by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece)</p> <h3><a href="ISDH2015Lobaz.pdf">DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS</a></h3> <p>by Petr Lobaz (Czech Republic)</p> <h3><a href="ISDH2015Matsushima.pdf">NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY</a></h3> <p>by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan)</p> <h3><a href="ISDH2015Sakamoto.pdf">FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL</a></h3> <p>by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan)</p> <h3><a href="ISDH2015Yoshikawa.pdf">IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM</a></h3> <p>by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan)</p> <h3><a href="ISDH2015Zhang.pdf">COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM</a></h3> <p>by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China)</p> <h3><a href="ISDH2015Zhao.pdf">DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY</a></h3> <p>by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China)</p> <h2>Session 5. Technical Applications</h2> <h3><a href="ISDH2015GaoHongyue.pdf">REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV</a></h3> <p>by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited)</p> <h3><a href="ISDH2015Parker.pdf">HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY"</a></h3> <p>by William Parker, Julie Parker (USA) (invited)</p> <h3><a href="ISDH2015Rastogi.pdf">ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY</a></h3> <p>by Pramod Rastogi (Switzerland) (invited)</p> <h3>HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS</h3> <p>by Turukhano B., Turukhano N. (Russia)</p> <h3><a href="ISDH2015Wesly.pdf">PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY</a></h3> <p>by Ed Wesly (USA)</p> <h3><a href="ISDH2015Chiu.pdf">HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE</a></h3> <p>by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan)</p> <h3>IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS</h3> <p>by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan)</p> <h3><a href="ISDH2015Tornari.pdf">HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART</a></h3> <p>by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece)</p> <h3><a href="ISDH2015Dyomin.pdf">AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES</a></h3> <p>by Victor Dyomin, Denis Kamenev (Russia)</p> <h3><a href="ISDH2015Burunkova.pdf">GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING</a></h3> <p>by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia)</p> <h3><a href="ISDH2015Osanlou.pdf">HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES</a></h3> <p>by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK)</p> <h3><a href="ISDH2015Ryu.pdf">OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES</a></h3> <p>by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia)</p> <h3><a href="ISDH2015Druzhin.pdf">HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY</a></h3> <p>by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia)</p> <h3><a href="ISDH2015Zherdev.pdf">PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES</a></h3> <p>by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia)</p> <h3><a href="ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS</a></h3> <p>by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China)</p> <h2>Session 6. Color Holography</h2> <h3><a href="ISDH2015Bjelkhagen.pdf">ULTRA-REALISTIC IMAGING AND OPTOCLONES</a></h3> <p>by Hans Bjelkhagen (UK)</p> <h3>ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY</h3> <p>by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland)</p> <h3><a href="ISDH2015Lembessis.pdf">THE "F" ADVENTURE</a></h3> <p>by Alkis Lembessis, Andreas Sarakinos (Greece)</p> <h3><a href="ISDH2015Odinokov.pdf">EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION</a></h3> <p>by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia)</p> <h3>METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA</h3> <p>by Natalith Palacios Ortega, Daniel Velasquez (Colombia)</p> <h3><a href="ISDH2015Shevtsov_Gentet.pdf">20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY</a></h3> <p>by Michael Shevtsov, Yves Gentet (Russia)</p> <h3><a href="ISDH2015Sarakinos.pdf">IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS</a></h3> <p>by Andreas Sarakinos, Alkis Lembessis (Greece)</p> <h3><a href="ISDH2015Stock.pdf">NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY</a></h3> <p>by Michelle Stock, Peter Andersen, Peter Skovgaard (USA)</p> <h3><a href="ISDH2015Shevtsov.pdf">MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION</a></h3> <p>by Michael Shevtsov (Russia)</p> <h3><a href="ISDH2015Yuan.pdf">MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS</a></h3> <p>by Quan Yuan (China)</p> <h2>Session 7. The Business of Holography</h2> <h3><a href="ISDH2015Fan.pdf">DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER</a></h3> <p>by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited)</p> <h3>STRIVING TO MAKE A LIVING WITH 3D IMAGES: QUITE A CHALLENGE...</h3> <p>by Pascal Gauchet (France)</p> <h3><a href="ISDH2015Beryozkina.pdf">SLAVICH HOLOGRAPHIC MATERIALS</a></h3> <p>by Juliay Beryozkina (Russia)</p> <h3><a href="ISDH2015Souparis1.pdf">FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES</a></h3> <p>by Hugues Souparis (France)</p> <h3><a href="ISDH2015Souparis2.pdf">THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART</a></h3> <p>by Hugues Souparis (France)</p> <h3>REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL</h3> <p>by Tim Sandford</p> <h3>SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS</h3> <p>by Leonid Tanin</p> <h2>Youth Session, Workshop</h2> <h3>RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD</h3> <p>by Nataliy Andreeva (Russia)</p> <h3><a href="ISDH2015Escarguel.pdf">UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT</a></h3> <p>by Alexandre Escarguel (France)</p> <h3>DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON</h3> <p>by Victor Dyomin (Russia)</p> <h3>HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES</h3> <p>by Boris Manukhin (Russia)</p> <h3>RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT</h3> <p>by Paramonov Alexandr (Russia)</p> <h3>SIMULATION OF WAVEFRONT PROPAGATION</h3> <p>by Nikolay Petrov (Russia)</p> 73210053b841bf4fc387a7f7c21362b057964be6 2696 2695 2015-07-19T12:21:03Z Jsfisher 1 wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the <a href="http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf">final program</a> available at <a href="http://isdh2015.ifmo.ru">ISDH 2015 web page</a>. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY: CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[ media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL ]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[ media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY ]] : by Sergey Gulyaev (Russia) ;[[ media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Art Concepts & Techniques == ;REFLECTIVE HOLOGRAPHY : by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal) ;RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY : by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK) ;MERGING THE MATERIAL WITH THE IMMATERIAL : by Richard Bruck (USA) ;COMMUNICATING IN 3D VISIBLE LANGUAGE : by Yin-Ren Chang, Martin Richardson (UK) ;HOLOGRAPHY AS AN ARCHITECTURAL DECORATION : by Setsuko Ishii (Japan) ;[[ media:ISDH2015John.pdf | AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK? ]] : by Pearl John (UK) ;[[ media:ISDH2015Vorzobova_Bulgakova.pdf | HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS ]] : by Nadezda Vorzobova, Vera Bulgakova (Russia) ;WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA : by John August Muth (USA) ;HOLOGRAPHY IN DESIGN : by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea) ;[[ media:ISDH2015Richardson.pdf | AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM : by Martin Richardson, Vivian Suresh Kumar Amos (UK) ;HOLOGRAMS IN CAVES : by Julio Ruiz, Luis Roves (Spain) ;[[ media:ISDH2015Khan.pdf | MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY ]] : by Javid Khan (UK) ;CREATING STEREOGRAMS ON AN iPhone : by Patrick Boyd (UK) ;[[media:ISDH2015Janardo.pdf | ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS]] : by Nuno Miguel José Janardo (Portugal) == Recording Materials & Processing ;[[media:ISDH2015Andreeva.pdf | DISPLAY HOLOGRAPHY AND NANOPLASMONICS]] : by Olga Andreeva (Russia) ;[[media:ISDH2015Banyasz.pdf | EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE]] : by István Bányász (Hungary) ;[[mediaISDH2015Ganzherli.pdf | HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS : by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia) ;[[media:ISDH2015Kutanov.pdf | DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM]] : by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan) ;[[media:ISDH2015Vorzobova_Ryabova.pdf | CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING]] : by Nadezda Vorzobova, Roze Ryabova (Russia) ;[[media:ISDH2015Gentet.pdf | RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's]] : by Yves Gentet (France) == Session 4. Electronic, Digital & CGH == <h3><a href="ISDH2015Brotherton-Ratcliffe.pdf">A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS</a></h3> <p>by David Brotherton-Ratcliffe (UK) (invited)</p> <h3><a href="ISDH2015Page.pdf">VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES</a></h3> <p>by Michael Page (Canada) (invited)</p> <h3><a href="ISDH2015Bove.pdf">PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS</a></h3> <p>by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA)</p> <h3><a href="ISDH2015Cheng.pdf">IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE</a></h3> <p>by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan)</p> <h3><a href="ISDH2015Jia.pdf">A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY</a></h3> <p>by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China)</p> <h3><a href="ISDH2015Morozov.pdf">INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER</a></h3> <p>by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia)</p> <h3><a href="ISDH2015Kang.pdf">COLOR HOLOGRAPHIC WAVEFRONT PRINTER</a></h3> <p>by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea)</p> <h3><a href="ISDH2015Kazempourradi.pdf">HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS</a></h3> <p>by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey)</p> <h3><a href="ISDH2015Khan2.pdf">A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS</a></h3> <p>by Javid Khan (UK)</p> <h3><a href="ISDH2015Kim.pdf">FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD</a></h3> <p>by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea)</p> <h3><a href="ISDH2015Kolyuchkin.pdf">THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS</a></h3> <p>by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia)</p> <h3><a href="ISDH2015Zlokazov.pdf">COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION</a></h3> <p>by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia)</p> <h3><a href="ISDH2015Paraschou.pdf">EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION</a></h3> <p>by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece)</p> <h3><a href="ISDH2015Lobaz.pdf">DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS</a></h3> <p>by Petr Lobaz (Czech Republic)</p> <h3><a href="ISDH2015Matsushima.pdf">NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY</a></h3> <p>by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan)</p> <h3><a href="ISDH2015Sakamoto.pdf">FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL</a></h3> <p>by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan)</p> <h3><a href="ISDH2015Yoshikawa.pdf">IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM</a></h3> <p>by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan)</p> <h3><a href="ISDH2015Zhang.pdf">COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM</a></h3> <p>by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China)</p> <h3><a href="ISDH2015Zhao.pdf">DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY</a></h3> <p>by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China)</p> <h2>Session 5. Technical Applications</h2> <h3><a href="ISDH2015GaoHongyue.pdf">REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV</a></h3> <p>by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited)</p> <h3><a href="ISDH2015Parker.pdf">HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY"</a></h3> <p>by William Parker, Julie Parker (USA) (invited)</p> <h3><a href="ISDH2015Rastogi.pdf">ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY</a></h3> <p>by Pramod Rastogi (Switzerland) (invited)</p> <h3>HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS</h3> <p>by Turukhano B., Turukhano N. (Russia)</p> <h3><a href="ISDH2015Wesly.pdf">PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY</a></h3> <p>by Ed Wesly (USA)</p> <h3><a href="ISDH2015Chiu.pdf">HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE</a></h3> <p>by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan)</p> <h3>IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS</h3> <p>by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan)</p> <h3><a href="ISDH2015Tornari.pdf">HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART</a></h3> <p>by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece)</p> <h3><a href="ISDH2015Dyomin.pdf">AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES</a></h3> <p>by Victor Dyomin, Denis Kamenev (Russia)</p> <h3><a href="ISDH2015Burunkova.pdf">GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING</a></h3> <p>by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia)</p> <h3><a href="ISDH2015Osanlou.pdf">HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES</a></h3> <p>by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK)</p> <h3><a href="ISDH2015Ryu.pdf">OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES</a></h3> <p>by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia)</p> <h3><a href="ISDH2015Druzhin.pdf">HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY</a></h3> <p>by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia)</p> <h3><a href="ISDH2015Zherdev.pdf">PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES</a></h3> <p>by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia)</p> <h3><a href="ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS</a></h3> <p>by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China)</p> <h2>Session 6. Color Holography</h2> <h3><a href="ISDH2015Bjelkhagen.pdf">ULTRA-REALISTIC IMAGING AND OPTOCLONES</a></h3> <p>by Hans Bjelkhagen (UK)</p> <h3>ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY</h3> <p>by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland)</p> <h3><a href="ISDH2015Lembessis.pdf">THE "F" ADVENTURE</a></h3> <p>by Alkis Lembessis, Andreas Sarakinos (Greece)</p> <h3><a href="ISDH2015Odinokov.pdf">EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION</a></h3> <p>by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia)</p> <h3>METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA</h3> <p>by Natalith Palacios Ortega, Daniel Velasquez (Colombia)</p> <h3><a href="ISDH2015Shevtsov_Gentet.pdf">20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY</a></h3> <p>by Michael Shevtsov, Yves Gentet (Russia)</p> <h3><a href="ISDH2015Sarakinos.pdf">IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS</a></h3> <p>by Andreas Sarakinos, Alkis Lembessis (Greece)</p> <h3><a href="ISDH2015Stock.pdf">NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY</a></h3> <p>by Michelle Stock, Peter Andersen, Peter Skovgaard (USA)</p> <h3><a href="ISDH2015Shevtsov.pdf">MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION</a></h3> <p>by Michael Shevtsov (Russia)</p> <h3><a href="ISDH2015Yuan.pdf">MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS</a></h3> <p>by Quan Yuan (China)</p> <h2>Session 7. The Business of Holography</h2> <h3><a href="ISDH2015Fan.pdf">DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER</a></h3> <p>by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited)</p> <h3>STRIVING TO MAKE A LIVING WITH 3D IMAGES: QUITE A CHALLENGE...</h3> <p>by Pascal Gauchet (France)</p> <h3><a href="ISDH2015Beryozkina.pdf">SLAVICH HOLOGRAPHIC MATERIALS</a></h3> <p>by Juliay Beryozkina (Russia)</p> <h3><a href="ISDH2015Souparis1.pdf">FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES</a></h3> <p>by Hugues Souparis (France)</p> <h3><a href="ISDH2015Souparis2.pdf">THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART</a></h3> <p>by Hugues Souparis (France)</p> <h3>REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL</h3> <p>by Tim Sandford</p> <h3>SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS</h3> <p>by Leonid Tanin</p> <h2>Youth Session, Workshop</h2> <h3>RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD</h3> <p>by Nataliy Andreeva (Russia)</p> <h3><a href="ISDH2015Escarguel.pdf">UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT</a></h3> <p>by Alexandre Escarguel (France)</p> <h3>DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON</h3> <p>by Victor Dyomin (Russia)</p> <h3>HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES</h3> <p>by Boris Manukhin (Russia)</p> <h3>RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT</h3> <p>by Paramonov Alexandr (Russia)</p> <h3>SIMULATION OF WAVEFRONT PROPAGATION</h3> <p>by Nikolay Petrov (Russia)</p> 68a59c870b7638395a7a078173431351f1c0e42b 2697 2696 2015-07-19T12:25:44Z Jsfisher 1 /* Art Concepts & Techniques */ wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the <a href="http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf">final program</a> available at <a href="http://isdh2015.ifmo.ru">ISDH 2015 web page</a>. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY: CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[ media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL ]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[ media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY ]] : by Sergey Gulyaev (Russia) ;[[ media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Art Concepts & Techniques == ;REFLECTIVE HOLOGRAPHY : by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal) ;RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY : by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK) ;MERGING THE MATERIAL WITH THE IMMATERIAL : by Richard Bruck (USA) ;COMMUNICATING IN 3D VISIBLE LANGUAGE : by Yin-Ren Chang, Martin Richardson (UK) ;HOLOGRAPHY AS AN ARCHITECTURAL DECORATION : by Setsuko Ishii (Japan) ;[[media:ISDH2015John.pdf | AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?]] : by Pearl John (UK) ;[[media:ISDH2015Vorzobova_Bulgakova.pdf | HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS]] : by Nadezda Vorzobova, Vera Bulgakova (Russia) ;WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA : by John August Muth (USA) ;HOLOGRAPHY IN DESIGN : by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea) ;[[media:ISDH2015Richardson.pdf | AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM]] : by Martin Richardson, Vivian Suresh Kumar Amos (UK) ;HOLOGRAMS IN CAVES : by Julio Ruiz, Luis Roves (Spain) ;[[media:ISDH2015Khan.pdf | MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY]] : by Javid Khan (UK) ;CREATING STEREOGRAMS ON AN iPhone : by Patrick Boyd (UK) ;[[media:ISDH2015Janardo.pdf | ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS]] : by Nuno Miguel José Janardo (Portugal) == Recording Materials & Processing == ;[[media:ISDH2015Andreeva.pdf | DISPLAY HOLOGRAPHY AND NANOPLASMONICS]] : by Olga Andreeva (Russia) ;[[media:ISDH2015Banyasz.pdf | EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE]] : by István Bányász (Hungary) ;[[mediaISDH2015Ganzherli.pdf | HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS]] : by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia) ;[[media:ISDH2015Kutanov.pdf | DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM]] : by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan) ;[[media:ISDH2015Vorzobova_Ryabova.pdf | CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING]] : by Nadezda Vorzobova, Roze Ryabova (Russia) ;[[media:ISDH2015Gentet.pdf | RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's]] : by Yves Gentet (France) == Session 4. Electronic, Digital & CGH == <h3><a href="ISDH2015Brotherton-Ratcliffe.pdf">A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS</a></h3> <p>by David Brotherton-Ratcliffe (UK) (invited)</p> <h3><a href="ISDH2015Page.pdf">VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES</a></h3> <p>by Michael Page (Canada) (invited)</p> <h3><a href="ISDH2015Bove.pdf">PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS</a></h3> <p>by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA)</p> <h3><a href="ISDH2015Cheng.pdf">IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE</a></h3> <p>by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan)</p> <h3><a href="ISDH2015Jia.pdf">A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY</a></h3> <p>by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China)</p> <h3><a href="ISDH2015Morozov.pdf">INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER</a></h3> <p>by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia)</p> <h3><a href="ISDH2015Kang.pdf">COLOR HOLOGRAPHIC WAVEFRONT PRINTER</a></h3> <p>by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea)</p> <h3><a href="ISDH2015Kazempourradi.pdf">HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS</a></h3> <p>by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey)</p> <h3><a href="ISDH2015Khan2.pdf">A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS</a></h3> <p>by Javid Khan (UK)</p> <h3><a href="ISDH2015Kim.pdf">FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD</a></h3> <p>by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea)</p> <h3><a href="ISDH2015Kolyuchkin.pdf">THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS</a></h3> <p>by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia)</p> <h3><a href="ISDH2015Zlokazov.pdf">COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION</a></h3> <p>by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia)</p> <h3><a href="ISDH2015Paraschou.pdf">EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION</a></h3> <p>by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece)</p> <h3><a href="ISDH2015Lobaz.pdf">DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS</a></h3> <p>by Petr Lobaz (Czech Republic)</p> <h3><a href="ISDH2015Matsushima.pdf">NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY</a></h3> <p>by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan)</p> <h3><a href="ISDH2015Sakamoto.pdf">FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL</a></h3> <p>by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan)</p> <h3><a href="ISDH2015Yoshikawa.pdf">IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM</a></h3> <p>by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan)</p> <h3><a href="ISDH2015Zhang.pdf">COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM</a></h3> <p>by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China)</p> <h3><a href="ISDH2015Zhao.pdf">DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY</a></h3> <p>by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China)</p> <h2>Session 5. Technical Applications</h2> <h3><a href="ISDH2015GaoHongyue.pdf">REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV</a></h3> <p>by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited)</p> <h3><a href="ISDH2015Parker.pdf">HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY"</a></h3> <p>by William Parker, Julie Parker (USA) (invited)</p> <h3><a href="ISDH2015Rastogi.pdf">ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY</a></h3> <p>by Pramod Rastogi (Switzerland) (invited)</p> <h3>HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS</h3> <p>by Turukhano B., Turukhano N. (Russia)</p> <h3><a href="ISDH2015Wesly.pdf">PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY</a></h3> <p>by Ed Wesly (USA)</p> <h3><a href="ISDH2015Chiu.pdf">HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE</a></h3> <p>by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan)</p> <h3>IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS</h3> <p>by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan)</p> <h3><a href="ISDH2015Tornari.pdf">HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART</a></h3> <p>by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece)</p> <h3><a href="ISDH2015Dyomin.pdf">AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES</a></h3> <p>by Victor Dyomin, Denis Kamenev (Russia)</p> <h3><a href="ISDH2015Burunkova.pdf">GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING</a></h3> <p>by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia)</p> <h3><a href="ISDH2015Osanlou.pdf">HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES</a></h3> <p>by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK)</p> <h3><a href="ISDH2015Ryu.pdf">OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES</a></h3> <p>by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia)</p> <h3><a href="ISDH2015Druzhin.pdf">HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY</a></h3> <p>by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia)</p> <h3><a href="ISDH2015Zherdev.pdf">PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES</a></h3> <p>by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia)</p> <h3><a href="ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS</a></h3> <p>by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China)</p> <h2>Session 6. Color Holography</h2> <h3><a href="ISDH2015Bjelkhagen.pdf">ULTRA-REALISTIC IMAGING AND OPTOCLONES</a></h3> <p>by Hans Bjelkhagen (UK)</p> <h3>ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY</h3> <p>by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland)</p> <h3><a href="ISDH2015Lembessis.pdf">THE "F" ADVENTURE</a></h3> <p>by Alkis Lembessis, Andreas Sarakinos (Greece)</p> <h3><a href="ISDH2015Odinokov.pdf">EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION</a></h3> <p>by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia)</p> <h3>METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA</h3> <p>by Natalith Palacios Ortega, Daniel Velasquez (Colombia)</p> <h3><a href="ISDH2015Shevtsov_Gentet.pdf">20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY</a></h3> <p>by Michael Shevtsov, Yves Gentet (Russia)</p> <h3><a href="ISDH2015Sarakinos.pdf">IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS</a></h3> <p>by Andreas Sarakinos, Alkis Lembessis (Greece)</p> <h3><a href="ISDH2015Stock.pdf">NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY</a></h3> <p>by Michelle Stock, Peter Andersen, Peter Skovgaard (USA)</p> <h3><a href="ISDH2015Shevtsov.pdf">MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION</a></h3> <p>by Michael Shevtsov (Russia)</p> <h3><a href="ISDH2015Yuan.pdf">MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS</a></h3> <p>by Quan Yuan (China)</p> <h2>Session 7. The Business of Holography</h2> <h3><a href="ISDH2015Fan.pdf">DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER</a></h3> <p>by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited)</p> <h3>STRIVING TO MAKE A LIVING WITH 3D IMAGES: QUITE A CHALLENGE...</h3> <p>by Pascal Gauchet (France)</p> <h3><a href="ISDH2015Beryozkina.pdf">SLAVICH HOLOGRAPHIC MATERIALS</a></h3> <p>by Juliay Beryozkina (Russia)</p> <h3><a href="ISDH2015Souparis1.pdf">FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES</a></h3> <p>by Hugues Souparis (France)</p> <h3><a href="ISDH2015Souparis2.pdf">THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART</a></h3> <p>by Hugues Souparis (France)</p> <h3>REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL</h3> <p>by Tim Sandford</p> <h3>SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS</h3> <p>by Leonid Tanin</p> <h2>Youth Session, Workshop</h2> <h3>RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD</h3> <p>by Nataliy Andreeva (Russia)</p> <h3><a href="ISDH2015Escarguel.pdf">UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT</a></h3> <p>by Alexandre Escarguel (France)</p> <h3>DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON</h3> <p>by Victor Dyomin (Russia)</p> <h3>HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES</h3> <p>by Boris Manukhin (Russia)</p> <h3>RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT</h3> <p>by Paramonov Alexandr (Russia)</p> <h3>SIMULATION OF WAVEFRONT PROPAGATION</h3> <p>by Nikolay Petrov (Russia)</p> b3e66afd80bc5b5b0b7ec8d900e3490e341c242c 2698 2697 2015-07-19T12:56:43Z Jsfisher 1 wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the <a href="http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf">final program</a> available at <a href="http://isdh2015.ifmo.ru">ISDH 2015 web page</a>. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY: CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[ media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL ]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[ media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY ]] : by Sergey Gulyaev (Russia) ;[[ media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Art Concepts & Techniques == ;REFLECTIVE HOLOGRAPHY : by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal) ;RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY : by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK) ;MERGING THE MATERIAL WITH THE IMMATERIAL : by Richard Bruck (USA) ;COMMUNICATING IN 3D VISIBLE LANGUAGE : by Yin-Ren Chang, Martin Richardson (UK) ;HOLOGRAPHY AS AN ARCHITECTURAL DECORATION : by Setsuko Ishii (Japan) ;[[media:ISDH2015John.pdf | AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?]] : by Pearl John (UK) ;[[media:ISDH2015Vorzobova_Bulgakova.pdf | HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS]] : by Nadezda Vorzobova, Vera Bulgakova (Russia) ;WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA : by John August Muth (USA) ;HOLOGRAPHY IN DESIGN : by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea) ;[[media:ISDH2015Richardson.pdf | AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM]] : by Martin Richardson, Vivian Suresh Kumar Amos (UK) ;HOLOGRAMS IN CAVES : by Julio Ruiz, Luis Roves (Spain) ;[[media:ISDH2015Khan.pdf | MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY]] : by Javid Khan (UK) ;CREATING STEREOGRAMS ON AN iPhone : by Patrick Boyd (UK) ;[[media:ISDH2015Janardo.pdf | ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS]] : by Nuno Miguel José Janardo (Portugal) == Recording Materials & Processing == ;[[media:ISDH2015Andreeva.pdf | DISPLAY HOLOGRAPHY AND NANOPLASMONICS]] : by Olga Andreeva (Russia) ;[[media:ISDH2015Banyasz.pdf | EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE]] : by István Bányász (Hungary) ;[[mediaISDH2015Ganzherli.pdf | HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS]] : by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia) ;[[media:ISDH2015Kutanov.pdf | DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM]] : by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan) ;[[media:ISDH2015Vorzobova_Ryabova.pdf | CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING]] : by Nadezda Vorzobova, Roze Ryabova (Russia) ;[[media:ISDH2015Gentet.pdf | RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's]] : by Yves Gentet (France) == Electronic, Digital & CGH == ;[[media:ISDH2015Brotherton-Ratcliffe.pdf | A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS]] : by David Brotherton-Ratcliffe (UK) (invited) ;[[media : ISDH2015Page.pdf | VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES]] : by Michael Page (Canada) (invited) ;[[media:ISDH2015Bove.pdf | PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS]] : by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA) ;[[media:ISDH2015Cheng.pdf | IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE]] : by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan) ;[[media:ISDH2015Jia.pdf | A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY]] : by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China) ;[[media:ISDH2015Morozov.pdf | INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER]] : by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia) ;[[media:ISDH2015Kang.pdf | COLOR HOLOGRAPHIC WAVEFRONT PRINTER]] : by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea) ;[[media:ISDH2015Kazempourradi.pdf | HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS]] : by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey) ;[[media:ISDH2015Khan2.pdf | A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS]] : by Javid Khan (UK) ;[[media:ISDH2015Kim.pdf | FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD]] : by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea) ;[[media:ISDH2015Kolyuchkin.pdf | THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS]] : by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia) ;[[media:ISDH2015Zlokazov.pdf | COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION]] : by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia) ;[[media:ISDH2015Paraschou.pdf | EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION]] : by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece) ;[[media:ISDH2015Lobaz.pdf | DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS]] : by Petr Lobaz (Czech Republic) ;[[media:ISDH2015Matsushima.pdf | NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY]] : by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan) ;[[media:ISDH2015Sakamoto.pdf | FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL]] : by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan) ;[[media:ISDH2015Yoshikawa.pdf | IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM : by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan) ;[[media:ISDH2015Zhang.pdf : COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM]] : by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China) ;[[media:ISDH2015Zhao.pdf | DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY]] : by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China) == Technical Applications == ;[[media:ISDH2015GaoHongyue.pdf | REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV]] : by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited) ;[[media:ISDH2015Parker.pdf | HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY]] : by William Parker, Julie Parker (USA) (invited) ;[[media:ISDH2015Rastogi.pdf | ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY]] : by Pramod Rastogi (Switzerland) (invited) ;HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS : by Turukhano B., Turukhano N. (Russia) ;[[media:ISDH2015Wesly.pdf | PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY]] : by Ed Wesly (USA) ;[[media:ISDH2015Chiu.pdf | HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE]] : by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan) ;IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS : by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan) ;[[media:ISDH2015Tornari.pdf | HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART]] : by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece) ;[[media:ISDH2015Dyomin.pdf |AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES]] : by Victor Dyomin, Denis Kamenev (Russia) ;[[media:ISDH2015Burunkova.pdf | GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING]] : by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia) ;[[media:ISDH2015Osanlou.pdf | HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES]] : by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK) ;[[media:ISDH2015Ryu.pdf | OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES]] : by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia) ;[[media:ISDH2015Druzhin.pdf | HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY]] : by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia) ;[[media:ISDH2015Zherdev.pdf | PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES ]] : by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia) ;[[media:ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS]] : by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China) == Color Holography == ;[[media:ISDH2015Bjelkhagen.pdf | ULTRA-REALISTIC IMAGING AND OPTOCLONES]] : by Hans Bjelkhagen (UK) ;ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY : by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland) ;[[media:ISDH2015Lembessis.pdf | THE "F" ADVENTURE]] : by Alkis Lembessis, Andreas Sarakinos (Greece) ;[[media:ISDH2015Odinokov.pdf | EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION]] : by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia) ;METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA : by Natalith Palacios Ortega, Daniel Velasquez (Colombia) ;[[media:ISDH2015Shevtsov_Gentet.pdf | 20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY]] : by Michael Shevtsov, Yves Gentet (Russia) ;[[media:ISDH2015Sarakinos.pdf | IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS]] : by Andreas Sarakinos, Alkis Lembessis (Greece) ;[[media:ISDH2015Stock.pdf | NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY]] : by Michelle Stock, Peter Andersen, Peter Skovgaard (USA) ;[[media:ISDH2015Shevtsov.pdf | MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION]] : by Michael Shevtsov (Russia) ;[[media:ISDH2015Yuan.pdf | MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS]] : by Quan Yuan (China) == The Business of Holography == ;[[media:ISDH2015Fan.pdf | DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER]] : by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited) ;STRIVING TO MAKE A LIVING WITH 3D IMAGES: QUITE A CHALLENGE... : by Pascal Gauchet (France) ;[[media:ISDH2015Beryozkina.pdf | SLAVICH HOLOGRAPHIC MATERIALS]] : by Juliay Beryozkina (Russia) ;[[media:ISDH2015Souparis1.pdf | FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES]] : by Hugues Souparis (France) ;[[media:ISDH2015Souparis2.pdf | THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART]] : by Hugues Souparis (France) ;REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL : by Tim Sandford ;SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS : by Leonid Tanin == Youth Session, Workshop == ;RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD : by Nataliy Andreeva (Russia) ;[[media:ISDH2015Escarguel.pdf | UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT]] : by Alexandre Escarguel (France) ;DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON : by Victor Dyomin (Russia) ;HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES : by Boris Manukhin (Russia) ;RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT : by Paramonov Alexandr (Russia) ;SIMULATION OF WAVEFRONT PROPAGATION : by Nikolay Petrov (Russia) a4abb55e345699ea369b7b0a082ddb52395ee207 2699 2698 2015-07-19T13:00:52Z Jsfisher 1 wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the [http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf final program] available at [http://isdh2015.ifmo.ru ISDH 2015 web page]. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY<nowiki>:</nowiki> CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY]] : by Sergey Gulyaev (Russia) ;[[media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Art Concepts & Techniques == ;REFLECTIVE HOLOGRAPHY : by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal) ;RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY : by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK) ;MERGING THE MATERIAL WITH THE IMMATERIAL : by Richard Bruck (USA) ;COMMUNICATING IN 3D VISIBLE LANGUAGE : by Yin-Ren Chang, Martin Richardson (UK) ;HOLOGRAPHY AS AN ARCHITECTURAL DECORATION : by Setsuko Ishii (Japan) ;[[media:ISDH2015John.pdf | AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?]] : by Pearl John (UK) ;[[media:ISDH2015Vorzobova_Bulgakova.pdf | HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS]] : by Nadezda Vorzobova, Vera Bulgakova (Russia) ;WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA : by John August Muth (USA) ;HOLOGRAPHY IN DESIGN : by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea) ;[[media:ISDH2015Richardson.pdf | AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM]] : by Martin Richardson, Vivian Suresh Kumar Amos (UK) ;HOLOGRAMS IN CAVES : by Julio Ruiz, Luis Roves (Spain) ;[[media:ISDH2015Khan.pdf | MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY]] : by Javid Khan (UK) ;CREATING STEREOGRAMS ON AN iPhone : by Patrick Boyd (UK) ;[[media:ISDH2015Janardo.pdf | ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS]] : by Nuno Miguel José Janardo (Portugal) == Recording Materials & Processing == ;[[media:ISDH2015Andreeva.pdf | DISPLAY HOLOGRAPHY AND NANOPLASMONICS]] : by Olga Andreeva (Russia) ;[[media:ISDH2015Banyasz.pdf | EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE]] : by István Bányász (Hungary) ;[[mediaISDH2015Ganzherli.pdf | HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS]] : by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia) ;[[media:ISDH2015Kutanov.pdf | DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM]] : by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan) ;[[media:ISDH2015Vorzobova_Ryabova.pdf | CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING]] : by Nadezda Vorzobova, Roze Ryabova (Russia) ;[[media:ISDH2015Gentet.pdf | RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's]] : by Yves Gentet (France) == Electronic, Digital & CGH == ;[[media:ISDH2015Brotherton-Ratcliffe.pdf | A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS]] : by David Brotherton-Ratcliffe (UK) (invited) ;[[media : ISDH2015Page.pdf | VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES]] : by Michael Page (Canada) (invited) ;[[media:ISDH2015Bove.pdf | PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS]] : by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA) ;[[media:ISDH2015Cheng.pdf | IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE]] : by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan) ;[[media:ISDH2015Jia.pdf | A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY]] : by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China) ;[[media:ISDH2015Morozov.pdf | INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER]] : by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia) ;[[media:ISDH2015Kang.pdf | COLOR HOLOGRAPHIC WAVEFRONT PRINTER]] : by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea) ;[[media:ISDH2015Kazempourradi.pdf | HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS]] : by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey) ;[[media:ISDH2015Khan2.pdf | A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS]] : by Javid Khan (UK) ;[[media:ISDH2015Kim.pdf | FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD]] : by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea) ;[[media:ISDH2015Kolyuchkin.pdf | THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS]] : by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia) ;[[media:ISDH2015Zlokazov.pdf | COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION]] : by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia) ;[[media:ISDH2015Paraschou.pdf | EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION]] : by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece) ;[[media:ISDH2015Lobaz.pdf | DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS]] : by Petr Lobaz (Czech Republic) ;[[media:ISDH2015Matsushima.pdf | NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY]] : by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan) ;[[media:ISDH2015Sakamoto.pdf | FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL]] : by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan) ;[[media:ISDH2015Yoshikawa.pdf | IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM : by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan) ;[[media:ISDH2015Zhang.pdf : COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM]] : by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China) ;[[media:ISDH2015Zhao.pdf | DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY]] : by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China) == Technical Applications == ;[[media:ISDH2015GaoHongyue.pdf | REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV]] : by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited) ;[[media:ISDH2015Parker.pdf | HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY]] : by William Parker, Julie Parker (USA) (invited) ;[[media:ISDH2015Rastogi.pdf | ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY]] : by Pramod Rastogi (Switzerland) (invited) ;HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS : by Turukhano B., Turukhano N. (Russia) ;[[media:ISDH2015Wesly.pdf | PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY]] : by Ed Wesly (USA) ;[[media:ISDH2015Chiu.pdf | HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE]] : by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan) ;IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS : by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan) ;[[media:ISDH2015Tornari.pdf | HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART]] : by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece) ;[[media:ISDH2015Dyomin.pdf |AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES]] : by Victor Dyomin, Denis Kamenev (Russia) ;[[media:ISDH2015Burunkova.pdf | GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING]] : by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia) ;[[media:ISDH2015Osanlou.pdf | HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES]] : by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK) ;[[media:ISDH2015Ryu.pdf | OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES]] : by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia) ;[[media:ISDH2015Druzhin.pdf | HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY]] : by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia) ;[[media:ISDH2015Zherdev.pdf | PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES ]] : by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia) ;[[media:ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS]] : by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China) == Color Holography == ;[[media:ISDH2015Bjelkhagen.pdf | ULTRA-REALISTIC IMAGING AND OPTOCLONES]] : by Hans Bjelkhagen (UK) ;ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY : by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland) ;[[media:ISDH2015Lembessis.pdf | THE "F" ADVENTURE]] : by Alkis Lembessis, Andreas Sarakinos (Greece) ;[[media:ISDH2015Odinokov.pdf | EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION]] : by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia) ;METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA : by Natalith Palacios Ortega, Daniel Velasquez (Colombia) ;[[media:ISDH2015Shevtsov_Gentet.pdf | 20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY]] : by Michael Shevtsov, Yves Gentet (Russia) ;[[media:ISDH2015Sarakinos.pdf | IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS]] : by Andreas Sarakinos, Alkis Lembessis (Greece) ;[[media:ISDH2015Stock.pdf | NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY]] : by Michelle Stock, Peter Andersen, Peter Skovgaard (USA) ;[[media:ISDH2015Shevtsov.pdf | MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION]] : by Michael Shevtsov (Russia) ;[[media:ISDH2015Yuan.pdf | MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS]] : by Quan Yuan (China) == The Business of Holography == ;[[media:ISDH2015Fan.pdf | DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER]] : by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited) ;STRIVING TO MAKE A LIVING WITH 3D IMAGES: QUITE A CHALLENGE... : by Pascal Gauchet (France) ;[[media:ISDH2015Beryozkina.pdf | SLAVICH HOLOGRAPHIC MATERIALS]] : by Juliay Beryozkina (Russia) ;[[media:ISDH2015Souparis1.pdf | FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES]] : by Hugues Souparis (France) ;[[media:ISDH2015Souparis2.pdf | THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART]] : by Hugues Souparis (France) ;REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL : by Tim Sandford ;SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS : by Leonid Tanin == Youth Session, Workshop == ;RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD : by Nataliy Andreeva (Russia) ;[[media:ISDH2015Escarguel.pdf | UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT]] : by Alexandre Escarguel (France) ;DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON : by Victor Dyomin (Russia) ;HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES : by Boris Manukhin (Russia) ;RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT : by Paramonov Alexandr (Russia) ;SIMULATION OF WAVEFRONT PROPAGATION : by Nikolay Petrov (Russia) 9d9a9be4eaa3aa27962704a5e1d44ae81674e761 2700 2699 2015-07-19T13:02:36Z Jsfisher 1 /* Recording Materials & Processing */ wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the [http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf final program] available at [http://isdh2015.ifmo.ru ISDH 2015 web page]. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY<nowiki>:</nowiki> CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY]] : by Sergey Gulyaev (Russia) ;[[media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Art Concepts & Techniques == ;REFLECTIVE HOLOGRAPHY : by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal) ;RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY : by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK) ;MERGING THE MATERIAL WITH THE IMMATERIAL : by Richard Bruck (USA) ;COMMUNICATING IN 3D VISIBLE LANGUAGE : by Yin-Ren Chang, Martin Richardson (UK) ;HOLOGRAPHY AS AN ARCHITECTURAL DECORATION : by Setsuko Ishii (Japan) ;[[media:ISDH2015John.pdf | AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?]] : by Pearl John (UK) ;[[media:ISDH2015Vorzobova_Bulgakova.pdf | HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS]] : by Nadezda Vorzobova, Vera Bulgakova (Russia) ;WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA : by John August Muth (USA) ;HOLOGRAPHY IN DESIGN : by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea) ;[[media:ISDH2015Richardson.pdf | AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM]] : by Martin Richardson, Vivian Suresh Kumar Amos (UK) ;HOLOGRAMS IN CAVES : by Julio Ruiz, Luis Roves (Spain) ;[[media:ISDH2015Khan.pdf | MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY]] : by Javid Khan (UK) ;CREATING STEREOGRAMS ON AN iPhone : by Patrick Boyd (UK) ;[[media:ISDH2015Janardo.pdf | ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS]] : by Nuno Miguel José Janardo (Portugal) == Recording Materials & Processing == ;[[media:ISDH2015Andreeva.pdf | DISPLAY HOLOGRAPHY AND NANOPLASMONICS]] : by Olga Andreeva (Russia) ;[[media:ISDH2015Banyasz.pdf | EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE]] : by István Bányász (Hungary) ;[[media:ISDH2015Ganzherli.pdf | HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS]] : by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia) ;[[media:ISDH2015Kutanov.pdf | DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM]] : by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan) ;[[media:ISDH2015Vorzobova_Ryabova.pdf | CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING]] : by Nadezda Vorzobova, Roze Ryabova (Russia) ;[[media:ISDH2015Gentet.pdf | RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's]] : by Yves Gentet (France) == Electronic, Digital & CGH == ;[[media:ISDH2015Brotherton-Ratcliffe.pdf | A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS]] : by David Brotherton-Ratcliffe (UK) (invited) ;[[media : ISDH2015Page.pdf | VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES]] : by Michael Page (Canada) (invited) ;[[media:ISDH2015Bove.pdf | PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS]] : by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA) ;[[media:ISDH2015Cheng.pdf | IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE]] : by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan) ;[[media:ISDH2015Jia.pdf | A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY]] : by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China) ;[[media:ISDH2015Morozov.pdf | INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER]] : by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia) ;[[media:ISDH2015Kang.pdf | COLOR HOLOGRAPHIC WAVEFRONT PRINTER]] : by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea) ;[[media:ISDH2015Kazempourradi.pdf | HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS]] : by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey) ;[[media:ISDH2015Khan2.pdf | A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS]] : by Javid Khan (UK) ;[[media:ISDH2015Kim.pdf | FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD]] : by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea) ;[[media:ISDH2015Kolyuchkin.pdf | THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS]] : by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia) ;[[media:ISDH2015Zlokazov.pdf | COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION]] : by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia) ;[[media:ISDH2015Paraschou.pdf | EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION]] : by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece) ;[[media:ISDH2015Lobaz.pdf | DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS]] : by Petr Lobaz (Czech Republic) ;[[media:ISDH2015Matsushima.pdf | NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY]] : by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan) ;[[media:ISDH2015Sakamoto.pdf | FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL]] : by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan) ;[[media:ISDH2015Yoshikawa.pdf | IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM : by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan) ;[[media:ISDH2015Zhang.pdf : COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM]] : by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China) ;[[media:ISDH2015Zhao.pdf | DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY]] : by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China) == Technical Applications == ;[[media:ISDH2015GaoHongyue.pdf | REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV]] : by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited) ;[[media:ISDH2015Parker.pdf | HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY]] : by William Parker, Julie Parker (USA) (invited) ;[[media:ISDH2015Rastogi.pdf | ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY]] : by Pramod Rastogi (Switzerland) (invited) ;HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS : by Turukhano B., Turukhano N. (Russia) ;[[media:ISDH2015Wesly.pdf | PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY]] : by Ed Wesly (USA) ;[[media:ISDH2015Chiu.pdf | HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE]] : by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan) ;IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS : by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan) ;[[media:ISDH2015Tornari.pdf | HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART]] : by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece) ;[[media:ISDH2015Dyomin.pdf |AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES]] : by Victor Dyomin, Denis Kamenev (Russia) ;[[media:ISDH2015Burunkova.pdf | GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING]] : by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia) ;[[media:ISDH2015Osanlou.pdf | HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES]] : by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK) ;[[media:ISDH2015Ryu.pdf | OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES]] : by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia) ;[[media:ISDH2015Druzhin.pdf | HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY]] : by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia) ;[[media:ISDH2015Zherdev.pdf | PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES ]] : by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia) ;[[media:ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS]] : by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China) == Color Holography == ;[[media:ISDH2015Bjelkhagen.pdf | ULTRA-REALISTIC IMAGING AND OPTOCLONES]] : by Hans Bjelkhagen (UK) ;ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY : by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland) ;[[media:ISDH2015Lembessis.pdf | THE "F" ADVENTURE]] : by Alkis Lembessis, Andreas Sarakinos (Greece) ;[[media:ISDH2015Odinokov.pdf | EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION]] : by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia) ;METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA : by Natalith Palacios Ortega, Daniel Velasquez (Colombia) ;[[media:ISDH2015Shevtsov_Gentet.pdf | 20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY]] : by Michael Shevtsov, Yves Gentet (Russia) ;[[media:ISDH2015Sarakinos.pdf | IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS]] : by Andreas Sarakinos, Alkis Lembessis (Greece) ;[[media:ISDH2015Stock.pdf | NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY]] : by Michelle Stock, Peter Andersen, Peter Skovgaard (USA) ;[[media:ISDH2015Shevtsov.pdf | MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION]] : by Michael Shevtsov (Russia) ;[[media:ISDH2015Yuan.pdf | MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS]] : by Quan Yuan (China) == The Business of Holography == ;[[media:ISDH2015Fan.pdf | DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER]] : by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited) ;STRIVING TO MAKE A LIVING WITH 3D IMAGES: QUITE A CHALLENGE... : by Pascal Gauchet (France) ;[[media:ISDH2015Beryozkina.pdf | SLAVICH HOLOGRAPHIC MATERIALS]] : by Juliay Beryozkina (Russia) ;[[media:ISDH2015Souparis1.pdf | FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES]] : by Hugues Souparis (France) ;[[media:ISDH2015Souparis2.pdf | THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART]] : by Hugues Souparis (France) ;REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL : by Tim Sandford ;SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS : by Leonid Tanin == Youth Session, Workshop == ;RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD : by Nataliy Andreeva (Russia) ;[[media:ISDH2015Escarguel.pdf | UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT]] : by Alexandre Escarguel (France) ;DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON : by Victor Dyomin (Russia) ;HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES : by Boris Manukhin (Russia) ;RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT : by Paramonov Alexandr (Russia) ;SIMULATION OF WAVEFRONT PROPAGATION : by Nikolay Petrov (Russia) b8afe16de9a287bcbe3c8abc1d928f3a5eaa681f 2701 2700 2015-07-19T13:05:39Z Jsfisher 1 /* Electronic, Digital & CGH */ wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the [http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf final program] available at [http://isdh2015.ifmo.ru ISDH 2015 web page]. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY<nowiki>:</nowiki> CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY]] : by Sergey Gulyaev (Russia) ;[[media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Art Concepts & Techniques == ;REFLECTIVE HOLOGRAPHY : by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal) ;RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY : by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK) ;MERGING THE MATERIAL WITH THE IMMATERIAL : by Richard Bruck (USA) ;COMMUNICATING IN 3D VISIBLE LANGUAGE : by Yin-Ren Chang, Martin Richardson (UK) ;HOLOGRAPHY AS AN ARCHITECTURAL DECORATION : by Setsuko Ishii (Japan) ;[[media:ISDH2015John.pdf | AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?]] : by Pearl John (UK) ;[[media:ISDH2015Vorzobova_Bulgakova.pdf | HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS]] : by Nadezda Vorzobova, Vera Bulgakova (Russia) ;WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA : by John August Muth (USA) ;HOLOGRAPHY IN DESIGN : by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea) ;[[media:ISDH2015Richardson.pdf | AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM]] : by Martin Richardson, Vivian Suresh Kumar Amos (UK) ;HOLOGRAMS IN CAVES : by Julio Ruiz, Luis Roves (Spain) ;[[media:ISDH2015Khan.pdf | MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY]] : by Javid Khan (UK) ;CREATING STEREOGRAMS ON AN iPhone : by Patrick Boyd (UK) ;[[media:ISDH2015Janardo.pdf | ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS]] : by Nuno Miguel José Janardo (Portugal) == Recording Materials & Processing == ;[[media:ISDH2015Andreeva.pdf | DISPLAY HOLOGRAPHY AND NANOPLASMONICS]] : by Olga Andreeva (Russia) ;[[media:ISDH2015Banyasz.pdf | EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE]] : by István Bányász (Hungary) ;[[media:ISDH2015Ganzherli.pdf | HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS]] : by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia) ;[[media:ISDH2015Kutanov.pdf | DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM]] : by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan) ;[[media:ISDH2015Vorzobova_Ryabova.pdf | CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING]] : by Nadezda Vorzobova, Roze Ryabova (Russia) ;[[media:ISDH2015Gentet.pdf | RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's]] : by Yves Gentet (France) == Electronic, Digital & CGH == ;[[media:ISDH2015Brotherton-Ratcliffe.pdf | A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS]] : by David Brotherton-Ratcliffe (UK) (invited) ;[[media : ISDH2015Page.pdf | VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES]] : by Michael Page (Canada) (invited) ;[[media:ISDH2015Bove.pdf | PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS]] : by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA) ;[[media:ISDH2015Cheng.pdf | IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE]] : by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan) ;[[media:ISDH2015Jia.pdf | A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY]] : by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China) ;[[media:ISDH2015Morozov.pdf | INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER]] : by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia) ;[[media:ISDH2015Kang.pdf | COLOR HOLOGRAPHIC WAVEFRONT PRINTER]] : by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea) ;[[media:ISDH2015Kazempourradi.pdf | HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS]] : by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey) ;[[media:ISDH2015Khan2.pdf | A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS]] : by Javid Khan (UK) ;[[media:ISDH2015Kim.pdf | FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD]] : by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea) ;[[media:ISDH2015Kolyuchkin.pdf | THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS]] : by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia) ;[[media:ISDH2015Zlokazov.pdf | COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION]] : by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia) ;[[media:ISDH2015Paraschou.pdf | EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION]] : by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece) ;[[media:ISDH2015Lobaz.pdf | DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS]] : by Petr Lobaz (Czech Republic) ;[[media:ISDH2015Matsushima.pdf | NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY]] : by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan) ;[[media:ISDH2015Sakamoto.pdf | FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL]] : by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan) ;[[media:ISDH2015Yoshikawa.pdf | IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM]] : by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan) ;[[media:ISDH2015Zhang.pdf : COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM]] : by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China) ;[[media:ISDH2015Zhao.pdf | DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY]] : by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China) == Technical Applications == ;[[media:ISDH2015GaoHongyue.pdf | REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV]] : by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited) ;[[media:ISDH2015Parker.pdf | HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY]] : by William Parker, Julie Parker (USA) (invited) ;[[media:ISDH2015Rastogi.pdf | ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY]] : by Pramod Rastogi (Switzerland) (invited) ;HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS : by Turukhano B., Turukhano N. (Russia) ;[[media:ISDH2015Wesly.pdf | PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY]] : by Ed Wesly (USA) ;[[media:ISDH2015Chiu.pdf | HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE]] : by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan) ;IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS : by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan) ;[[media:ISDH2015Tornari.pdf | HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART]] : by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece) ;[[media:ISDH2015Dyomin.pdf |AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES]] : by Victor Dyomin, Denis Kamenev (Russia) ;[[media:ISDH2015Burunkova.pdf | GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING]] : by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia) ;[[media:ISDH2015Osanlou.pdf | HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES]] : by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK) ;[[media:ISDH2015Ryu.pdf | OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES]] : by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia) ;[[media:ISDH2015Druzhin.pdf | HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY]] : by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia) ;[[media:ISDH2015Zherdev.pdf | PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES ]] : by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia) ;[[media:ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS]] : by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China) == Color Holography == ;[[media:ISDH2015Bjelkhagen.pdf | ULTRA-REALISTIC IMAGING AND OPTOCLONES]] : by Hans Bjelkhagen (UK) ;ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY : by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland) ;[[media:ISDH2015Lembessis.pdf | THE "F" ADVENTURE]] : by Alkis Lembessis, Andreas Sarakinos (Greece) ;[[media:ISDH2015Odinokov.pdf | EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION]] : by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia) ;METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA : by Natalith Palacios Ortega, Daniel Velasquez (Colombia) ;[[media:ISDH2015Shevtsov_Gentet.pdf | 20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY]] : by Michael Shevtsov, Yves Gentet (Russia) ;[[media:ISDH2015Sarakinos.pdf | IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS]] : by Andreas Sarakinos, Alkis Lembessis (Greece) ;[[media:ISDH2015Stock.pdf | NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY]] : by Michelle Stock, Peter Andersen, Peter Skovgaard (USA) ;[[media:ISDH2015Shevtsov.pdf | MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION]] : by Michael Shevtsov (Russia) ;[[media:ISDH2015Yuan.pdf | MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS]] : by Quan Yuan (China) == The Business of Holography == ;[[media:ISDH2015Fan.pdf | DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER]] : by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited) ;STRIVING TO MAKE A LIVING WITH 3D IMAGES: QUITE A CHALLENGE... : by Pascal Gauchet (France) ;[[media:ISDH2015Beryozkina.pdf | SLAVICH HOLOGRAPHIC MATERIALS]] : by Juliay Beryozkina (Russia) ;[[media:ISDH2015Souparis1.pdf | FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES]] : by Hugues Souparis (France) ;[[media:ISDH2015Souparis2.pdf | THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART]] : by Hugues Souparis (France) ;REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL : by Tim Sandford ;SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS : by Leonid Tanin == Youth Session, Workshop == ;RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD : by Nataliy Andreeva (Russia) ;[[media:ISDH2015Escarguel.pdf | UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT]] : by Alexandre Escarguel (France) ;DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON : by Victor Dyomin (Russia) ;HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES : by Boris Manukhin (Russia) ;RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT : by Paramonov Alexandr (Russia) ;SIMULATION OF WAVEFRONT PROPAGATION : by Nikolay Petrov (Russia) 2cc901bf16defef11ca6b8428bdb368e4857aad1 2702 2701 2015-07-19T13:07:10Z Jsfisher 1 /* Electronic, Digital & CGH */ wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the [http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf final program] available at [http://isdh2015.ifmo.ru ISDH 2015 web page]. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY<nowiki>:</nowiki> CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY]] : by Sergey Gulyaev (Russia) ;[[media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Art Concepts & Techniques == ;REFLECTIVE HOLOGRAPHY : by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal) ;RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY : by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK) ;MERGING THE MATERIAL WITH THE IMMATERIAL : by Richard Bruck (USA) ;COMMUNICATING IN 3D VISIBLE LANGUAGE : by Yin-Ren Chang, Martin Richardson (UK) ;HOLOGRAPHY AS AN ARCHITECTURAL DECORATION : by Setsuko Ishii (Japan) ;[[media:ISDH2015John.pdf | AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?]] : by Pearl John (UK) ;[[media:ISDH2015Vorzobova_Bulgakova.pdf | HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS]] : by Nadezda Vorzobova, Vera Bulgakova (Russia) ;WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA : by John August Muth (USA) ;HOLOGRAPHY IN DESIGN : by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea) ;[[media:ISDH2015Richardson.pdf | AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM]] : by Martin Richardson, Vivian Suresh Kumar Amos (UK) ;HOLOGRAMS IN CAVES : by Julio Ruiz, Luis Roves (Spain) ;[[media:ISDH2015Khan.pdf | MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY]] : by Javid Khan (UK) ;CREATING STEREOGRAMS ON AN iPhone : by Patrick Boyd (UK) ;[[media:ISDH2015Janardo.pdf | ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS]] : by Nuno Miguel José Janardo (Portugal) == Recording Materials & Processing == ;[[media:ISDH2015Andreeva.pdf | DISPLAY HOLOGRAPHY AND NANOPLASMONICS]] : by Olga Andreeva (Russia) ;[[media:ISDH2015Banyasz.pdf | EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE]] : by István Bányász (Hungary) ;[[media:ISDH2015Ganzherli.pdf | HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS]] : by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia) ;[[media:ISDH2015Kutanov.pdf | DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM]] : by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan) ;[[media:ISDH2015Vorzobova_Ryabova.pdf | CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING]] : by Nadezda Vorzobova, Roze Ryabova (Russia) ;[[media:ISDH2015Gentet.pdf | RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's]] : by Yves Gentet (France) == Electronic, Digital & CGH == ;[[media:ISDH2015Brotherton-Ratcliffe.pdf | A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS]] : by David Brotherton-Ratcliffe (UK) (invited) ;[[media : ISDH2015Page.pdf | VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES]] : by Michael Page (Canada) (invited) ;[[media:ISDH2015Bove.pdf | PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS]] : by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA) ;[[media:ISDH2015Cheng.pdf | IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE]] : by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan) ;[[media:ISDH2015Jia.pdf | A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY]] : by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China) ;[[media:ISDH2015Morozov.pdf | INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER]] : by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia) ;[[media:ISDH2015Kang.pdf | COLOR HOLOGRAPHIC WAVEFRONT PRINTER]] : by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea) ;[[media:ISDH2015Kazempourradi.pdf | HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS]] : by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey) ;[[media:ISDH2015Khan2.pdf | A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS]] : by Javid Khan (UK) ;[[media:ISDH2015Kim.pdf | FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD]] : by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea) ;[[media:ISDH2015Kolyuchkin.pdf | THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS]] : by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia) ;[[media:ISDH2015Zlokazov.pdf | COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION]] : by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia) ;[[media:ISDH2015Paraschou.pdf | EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION]] : by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece) ;[[media:ISDH2015Lobaz.pdf | DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS]] : by Petr Lobaz (Czech Republic) ;[[media:ISDH2015Matsushima.pdf | NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY]] : by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan) ;[[media:ISDH2015Sakamoto.pdf | FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL]] : by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan) ;[[media:ISDH2015Yoshikawa.pdf | IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM]] : by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan) ;[[media:ISDH2015Zhang.pdf | COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM]] : by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China) ;[[media:ISDH2015Zhao.pdf | DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY]] : by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China) == Technical Applications == ;[[media:ISDH2015GaoHongyue.pdf | REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV]] : by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited) ;[[media:ISDH2015Parker.pdf | HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY]] : by William Parker, Julie Parker (USA) (invited) ;[[media:ISDH2015Rastogi.pdf | ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY]] : by Pramod Rastogi (Switzerland) (invited) ;HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS : by Turukhano B., Turukhano N. (Russia) ;[[media:ISDH2015Wesly.pdf | PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY]] : by Ed Wesly (USA) ;[[media:ISDH2015Chiu.pdf | HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE]] : by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan) ;IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS : by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan) ;[[media:ISDH2015Tornari.pdf | HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART]] : by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece) ;[[media:ISDH2015Dyomin.pdf |AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES]] : by Victor Dyomin, Denis Kamenev (Russia) ;[[media:ISDH2015Burunkova.pdf | GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING]] : by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia) ;[[media:ISDH2015Osanlou.pdf | HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES]] : by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK) ;[[media:ISDH2015Ryu.pdf | OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES]] : by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia) ;[[media:ISDH2015Druzhin.pdf | HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY]] : by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia) ;[[media:ISDH2015Zherdev.pdf | PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES ]] : by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia) ;[[media:ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS]] : by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China) == Color Holography == ;[[media:ISDH2015Bjelkhagen.pdf | ULTRA-REALISTIC IMAGING AND OPTOCLONES]] : by Hans Bjelkhagen (UK) ;ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY : by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland) ;[[media:ISDH2015Lembessis.pdf | THE "F" ADVENTURE]] : by Alkis Lembessis, Andreas Sarakinos (Greece) ;[[media:ISDH2015Odinokov.pdf | EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION]] : by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia) ;METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA : by Natalith Palacios Ortega, Daniel Velasquez (Colombia) ;[[media:ISDH2015Shevtsov_Gentet.pdf | 20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY]] : by Michael Shevtsov, Yves Gentet (Russia) ;[[media:ISDH2015Sarakinos.pdf | IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS]] : by Andreas Sarakinos, Alkis Lembessis (Greece) ;[[media:ISDH2015Stock.pdf | NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY]] : by Michelle Stock, Peter Andersen, Peter Skovgaard (USA) ;[[media:ISDH2015Shevtsov.pdf | MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION]] : by Michael Shevtsov (Russia) ;[[media:ISDH2015Yuan.pdf | MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS]] : by Quan Yuan (China) == The Business of Holography == ;[[media:ISDH2015Fan.pdf | DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER]] : by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited) ;STRIVING TO MAKE A LIVING WITH 3D IMAGES: QUITE A CHALLENGE... : by Pascal Gauchet (France) ;[[media:ISDH2015Beryozkina.pdf | SLAVICH HOLOGRAPHIC MATERIALS]] : by Juliay Beryozkina (Russia) ;[[media:ISDH2015Souparis1.pdf | FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES]] : by Hugues Souparis (France) ;[[media:ISDH2015Souparis2.pdf | THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART]] : by Hugues Souparis (France) ;REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL : by Tim Sandford ;SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS : by Leonid Tanin == Youth Session, Workshop == ;RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD : by Nataliy Andreeva (Russia) ;[[media:ISDH2015Escarguel.pdf | UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT]] : by Alexandre Escarguel (France) ;DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON : by Victor Dyomin (Russia) ;HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES : by Boris Manukhin (Russia) ;RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT : by Paramonov Alexandr (Russia) ;SIMULATION OF WAVEFRONT PROPAGATION : by Nikolay Petrov (Russia) 210ec96d0ab5d6b84d84567b630b8caee4575c6d 2703 2702 2015-07-19T13:08:18Z Jsfisher 1 /* The Business of Holography */ wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the [http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf final program] available at [http://isdh2015.ifmo.ru ISDH 2015 web page]. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY<nowiki>:</nowiki> CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY]] : by Sergey Gulyaev (Russia) ;[[media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Art Concepts & Techniques == ;REFLECTIVE HOLOGRAPHY : by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal) ;RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY : by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK) ;MERGING THE MATERIAL WITH THE IMMATERIAL : by Richard Bruck (USA) ;COMMUNICATING IN 3D VISIBLE LANGUAGE : by Yin-Ren Chang, Martin Richardson (UK) ;HOLOGRAPHY AS AN ARCHITECTURAL DECORATION : by Setsuko Ishii (Japan) ;[[media:ISDH2015John.pdf | AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?]] : by Pearl John (UK) ;[[media:ISDH2015Vorzobova_Bulgakova.pdf | HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS]] : by Nadezda Vorzobova, Vera Bulgakova (Russia) ;WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA : by John August Muth (USA) ;HOLOGRAPHY IN DESIGN : by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea) ;[[media:ISDH2015Richardson.pdf | AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM]] : by Martin Richardson, Vivian Suresh Kumar Amos (UK) ;HOLOGRAMS IN CAVES : by Julio Ruiz, Luis Roves (Spain) ;[[media:ISDH2015Khan.pdf | MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY]] : by Javid Khan (UK) ;CREATING STEREOGRAMS ON AN iPhone : by Patrick Boyd (UK) ;[[media:ISDH2015Janardo.pdf | ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS]] : by Nuno Miguel José Janardo (Portugal) == Recording Materials & Processing == ;[[media:ISDH2015Andreeva.pdf | DISPLAY HOLOGRAPHY AND NANOPLASMONICS]] : by Olga Andreeva (Russia) ;[[media:ISDH2015Banyasz.pdf | EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE]] : by István Bányász (Hungary) ;[[media:ISDH2015Ganzherli.pdf | HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS]] : by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia) ;[[media:ISDH2015Kutanov.pdf | DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM]] : by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan) ;[[media:ISDH2015Vorzobova_Ryabova.pdf | CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING]] : by Nadezda Vorzobova, Roze Ryabova (Russia) ;[[media:ISDH2015Gentet.pdf | RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's]] : by Yves Gentet (France) == Electronic, Digital & CGH == ;[[media:ISDH2015Brotherton-Ratcliffe.pdf | A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS]] : by David Brotherton-Ratcliffe (UK) (invited) ;[[media : ISDH2015Page.pdf | VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES]] : by Michael Page (Canada) (invited) ;[[media:ISDH2015Bove.pdf | PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS]] : by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA) ;[[media:ISDH2015Cheng.pdf | IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE]] : by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan) ;[[media:ISDH2015Jia.pdf | A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY]] : by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China) ;[[media:ISDH2015Morozov.pdf | INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER]] : by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia) ;[[media:ISDH2015Kang.pdf | COLOR HOLOGRAPHIC WAVEFRONT PRINTER]] : by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea) ;[[media:ISDH2015Kazempourradi.pdf | HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS]] : by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey) ;[[media:ISDH2015Khan2.pdf | A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS]] : by Javid Khan (UK) ;[[media:ISDH2015Kim.pdf | FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD]] : by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea) ;[[media:ISDH2015Kolyuchkin.pdf | THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS]] : by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia) ;[[media:ISDH2015Zlokazov.pdf | COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION]] : by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia) ;[[media:ISDH2015Paraschou.pdf | EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION]] : by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece) ;[[media:ISDH2015Lobaz.pdf | DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS]] : by Petr Lobaz (Czech Republic) ;[[media:ISDH2015Matsushima.pdf | NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY]] : by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan) ;[[media:ISDH2015Sakamoto.pdf | FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL]] : by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan) ;[[media:ISDH2015Yoshikawa.pdf | IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM]] : by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan) ;[[media:ISDH2015Zhang.pdf | COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM]] : by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China) ;[[media:ISDH2015Zhao.pdf | DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY]] : by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China) == Technical Applications == ;[[media:ISDH2015GaoHongyue.pdf | REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV]] : by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited) ;[[media:ISDH2015Parker.pdf | HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY]] : by William Parker, Julie Parker (USA) (invited) ;[[media:ISDH2015Rastogi.pdf | ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY]] : by Pramod Rastogi (Switzerland) (invited) ;HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS : by Turukhano B., Turukhano N. (Russia) ;[[media:ISDH2015Wesly.pdf | PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY]] : by Ed Wesly (USA) ;[[media:ISDH2015Chiu.pdf | HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE]] : by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan) ;IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS : by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan) ;[[media:ISDH2015Tornari.pdf | HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART]] : by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece) ;[[media:ISDH2015Dyomin.pdf |AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES]] : by Victor Dyomin, Denis Kamenev (Russia) ;[[media:ISDH2015Burunkova.pdf | GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING]] : by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia) ;[[media:ISDH2015Osanlou.pdf | HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES]] : by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK) ;[[media:ISDH2015Ryu.pdf | OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES]] : by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia) ;[[media:ISDH2015Druzhin.pdf | HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY]] : by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia) ;[[media:ISDH2015Zherdev.pdf | PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES ]] : by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia) ;[[media:ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS]] : by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China) == Color Holography == ;[[media:ISDH2015Bjelkhagen.pdf | ULTRA-REALISTIC IMAGING AND OPTOCLONES]] : by Hans Bjelkhagen (UK) ;ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY : by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland) ;[[media:ISDH2015Lembessis.pdf | THE "F" ADVENTURE]] : by Alkis Lembessis, Andreas Sarakinos (Greece) ;[[media:ISDH2015Odinokov.pdf | EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION]] : by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia) ;METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA : by Natalith Palacios Ortega, Daniel Velasquez (Colombia) ;[[media:ISDH2015Shevtsov_Gentet.pdf | 20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY]] : by Michael Shevtsov, Yves Gentet (Russia) ;[[media:ISDH2015Sarakinos.pdf | IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS]] : by Andreas Sarakinos, Alkis Lembessis (Greece) ;[[media:ISDH2015Stock.pdf | NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY]] : by Michelle Stock, Peter Andersen, Peter Skovgaard (USA) ;[[media:ISDH2015Shevtsov.pdf | MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION]] : by Michael Shevtsov (Russia) ;[[media:ISDH2015Yuan.pdf | MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS]] : by Quan Yuan (China) == The Business of Holography == ;[[media:ISDH2015Fan.pdf | DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER]] : by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited) ;STRIVING TO MAKE A LIVING WITH 3D IMAGES<nowiki>:</nowiki> QUITE A CHALLENGE... : by Pascal Gauchet (France) ;[[media:ISDH2015Beryozkina.pdf | SLAVICH HOLOGRAPHIC MATERIALS]] : by Juliay Beryozkina (Russia) ;[[media:ISDH2015Souparis1.pdf | FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES]] : by Hugues Souparis (France) ;[[media:ISDH2015Souparis2.pdf | THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART]] : by Hugues Souparis (France) ;REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL : by Tim Sandford ;SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS : by Leonid Tanin == Youth Session, Workshop == ;RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD : by Nataliy Andreeva (Russia) ;[[media:ISDH2015Escarguel.pdf | UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT]] : by Alexandre Escarguel (France) ;DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON : by Victor Dyomin (Russia) ;HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES : by Boris Manukhin (Russia) ;RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT : by Paramonov Alexandr (Russia) ;SIMULATION OF WAVEFRONT PROPAGATION : by Nikolay Petrov (Russia) 7d4eabebf9fc60b03081d5c75aedca2bc92433cd 2710 2703 2015-07-19T15:17:32Z Jsfisher 1 wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the [http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf final program] available at [http://isdh2015.ifmo.ru ISDH 2015 web page]. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <br><i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY<nowiki>:</nowiki> CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY: A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY]] : by Sergey Gulyaev (Russia) ;[[media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Art Concepts & Techniques == ;REFLECTIVE HOLOGRAPHY : by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal) ;RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY : by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK) ;MERGING THE MATERIAL WITH THE IMMATERIAL : by Richard Bruck (USA) ;COMMUNICATING IN 3D VISIBLE LANGUAGE : by Yin-Ren Chang, Martin Richardson (UK) ;HOLOGRAPHY AS AN ARCHITECTURAL DECORATION : by Setsuko Ishii (Japan) ;[[media:ISDH2015John.pdf | AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?]] : by Pearl John (UK) ;[[media:ISDH2015Vorzobova_Bulgakova.pdf | HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS]] : by Nadezda Vorzobova, Vera Bulgakova (Russia) ;WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA : by John August Muth (USA) ;HOLOGRAPHY IN DESIGN : by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea) ;[[media:ISDH2015Richardson.pdf | AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM]] : by Martin Richardson, Vivian Suresh Kumar Amos (UK) ;HOLOGRAMS IN CAVES : by Julio Ruiz, Luis Roves (Spain) ;[[media:ISDH2015Khan.pdf | MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY]] : by Javid Khan (UK) ;CREATING STEREOGRAMS ON AN iPhone : by Patrick Boyd (UK) ;[[media:ISDH2015Janardo.pdf | ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS]] : by Nuno Miguel José Janardo (Portugal) == Recording Materials & Processing == ;[[media:ISDH2015Andreeva.pdf | DISPLAY HOLOGRAPHY AND NANOPLASMONICS]] : by Olga Andreeva (Russia) ;[[media:ISDH2015Banyasz.pdf | EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE]] : by István Bányász (Hungary) ;[[media:ISDH2015Ganzherli.pdf | HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS]] : by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia) ;[[media:ISDH2015Kutanov.pdf | DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM]] : by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan) ;[[media:ISDH2015Vorzobova_Ryabova.pdf | CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING]] : by Nadezda Vorzobova, Roze Ryabova (Russia) ;[[media:ISDH2015Gentet.pdf | RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's]] : by Yves Gentet (France) == Electronic, Digital & CGH == ;[[media:ISDH2015Brotherton-Ratcliffe.pdf | A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS]] : by David Brotherton-Ratcliffe (UK) (invited) ;[[media : ISDH2015Page.pdf | VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES]] : by Michael Page (Canada) (invited) ;[[media:ISDH2015Bove.pdf | PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS]] : by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA) ;[[media:ISDH2015Cheng.pdf | IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE]] : by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan) ;[[media:ISDH2015Jia.pdf | A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY]] : by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China) ;[[media:ISDH2015Morozov.pdf | INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER]] : by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia) ;[[media:ISDH2015Kang.pdf | COLOR HOLOGRAPHIC WAVEFRONT PRINTER]] : by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea) ;[[media:ISDH2015Kazempourradi.pdf | HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS]] : by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey) ;[[media:ISDH2015Khan2.pdf | A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS]] : by Javid Khan (UK) ;[[media:ISDH2015Kim.pdf | FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD]] : by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea) ;[[media:ISDH2015Kolyuchkin.pdf | THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS]] : by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia) ;[[media:ISDH2015Zlokazov.pdf | COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION]] : by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia) ;[[media:ISDH2015Paraschou.pdf | EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION]] : by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece) ;[[media:ISDH2015Lobaz.pdf | DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS]] : by Petr Lobaz (Czech Republic) ;[[media:ISDH2015Matsushima.pdf | NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY]] : by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan) ;[[media:ISDH2015Sakamoto.pdf | FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL]] : by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan) ;[[media:ISDH2015Yoshikawa.pdf | IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM]] : by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan) ;[[media:ISDH2015Zhang.pdf | COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM]] : by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China) ;[[media:ISDH2015Zhao.pdf | DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY]] : by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China) == Technical Applications == ;[[media:ISDH2015GaoHongyue.pdf | REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV]] : by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited) ;[[media:ISDH2015Parker.pdf | HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY]] : by William Parker, Julie Parker (USA) (invited) ;[[media:ISDH2015Rastogi.pdf | ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY]] : by Pramod Rastogi (Switzerland) (invited) ;HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS : by Turukhano B., Turukhano N. (Russia) ;[[media:ISDH2015Wesly.pdf | PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY]] : by Ed Wesly (USA) ;[[media:ISDH2015Chiu.pdf | HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE]] : by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan) ;IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS : by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan) ;[[media:ISDH2015Tornari.pdf | HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART]] : by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece) ;[[media:ISDH2015Dyomin.pdf |AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES]] : by Victor Dyomin, Denis Kamenev (Russia) ;[[media:ISDH2015Burunkova.pdf | GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING]] : by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia) ;[[media:ISDH2015Osanlou.pdf | HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES]] : by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK) ;[[media:ISDH2015Ryu.pdf | OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES]] : by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia) ;[[media:ISDH2015Druzhin.pdf | HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY]] : by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia) ;[[media:ISDH2015Zherdev.pdf | PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES ]] : by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia) ;[[media:ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS]] : by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China) == Color Holography == ;[[media:ISDH2015Bjelkhagen.pdf | ULTRA-REALISTIC IMAGING AND OPTOCLONES]] : by Hans Bjelkhagen (UK) ;ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY : by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland) ;[[media:ISDH2015Lembessis.pdf | THE "F" ADVENTURE]] : by Alkis Lembessis, Andreas Sarakinos (Greece) ;[[media:ISDH2015Odinokov.pdf | EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION]] : by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia) ;METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA : by Natalith Palacios Ortega, Daniel Velasquez (Colombia) ;[[media:ISDH2015Shevtsov_Gentet.pdf | 20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY]] : by Michael Shevtsov, Yves Gentet (Russia) ;[[media:ISDH2015Sarakinos.pdf | IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS]] : by Andreas Sarakinos, Alkis Lembessis (Greece) ;[[media:ISDH2015Stock.pdf | NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY]] : by Michelle Stock, Peter Andersen, Peter Skovgaard (USA) ;[[media:ISDH2015Shevtsov.pdf | MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION]] : by Michael Shevtsov (Russia) ;[[media:ISDH2015Yuan.pdf | MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS]] : by Quan Yuan (China) == The Business of Holography == ;[[media:ISDH2015Fan.pdf | DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER]] : by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited) ;STRIVING TO MAKE A LIVING WITH 3D IMAGES<nowiki>:</nowiki> QUITE A CHALLENGE... : by Pascal Gauchet (France) ;[[media:ISDH2015Beryozkina.pdf | SLAVICH HOLOGRAPHIC MATERIALS]] : by Juliay Beryozkina (Russia) ;[[media:ISDH2015Souparis1.pdf | FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES]] : by Hugues Souparis (France) ;[[media:ISDH2015Souparis2.pdf | THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART]] : by Hugues Souparis (France) ;REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL : by Tim Sandford ;SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS : by Leonid Tanin == Youth Session, Workshop == ;RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD : by Nataliy Andreeva (Russia) ;[[media:ISDH2015Escarguel.pdf | UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT]] : by Alexandre Escarguel (France) ;DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON : by Victor Dyomin (Russia) ;HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES : by Boris Manukhin (Russia) ;RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT : by Paramonov Alexandr (Russia) ;SIMULATION OF WAVEFRONT PROPAGATION : by Nikolay Petrov (Russia) dd263f734fabe1a9a78d81856ddb3e6a6eecaa4f 2711 2710 2015-07-19T15:38:56Z Jsfisher 1 /* Plenary Session */ wikitext text/x-wiki <big>'''10th International Symposium on Display Holography (ISDH-2015)'''</big> The list below is a copy from the [http://isdh2015.ifmo.ru/docs/ISDH2015_program.pdf final program] available at [http://isdh2015.ifmo.ru ISDH 2015 web page]. I took many photographs of the slides, especially ones based on text information. Artistic presentations are mostly missing, as they usually contained just images and the slides alone are hardly useful; moreover, quality of photographs is acceptable for text and graphs, not for image reproduction. Sometimes I did not catch all slides, but the PDF's below contain substantial part of the presentation. This page is meant as a temporary substitute of proper conference proceedings. Enjoy! <br><i>Petr Lobaz</i> == Plenary Session == ;HOLOGRAPHY<nowiki>:</nowiki> CULTURE, ART AND INFORMATION TECHNOLOGY :by Alec Jeong (USA) (invited) ;FROM WAVE PHOTOGRAPHY TO 3D HOLOGRAPHY AND BEYOND :by Vladimir Markov (USA) (invited) ;DISPLAY HOLOGRAPHY<nowiki>:</nowiki> A DISAPPOINTING HISTORY BUT A BRIGHT FUTURE? :by Ian M. Lancaster (UK) (invited) == History, Culture, and Education == ;[[media:ISDH2015Pombo.pdf | HOLOGRAPHY FOR ALL]] : by Pedro Pombo, Emanuel Santos, Carolina Magalhaes (Portugal) ;ADVANCE IN HOLOGRAPHY FIELD IN THE TERRITORY OF THE FORMER SOVIET UNION : by Leonid V. Tanin (Belarus) (invited) ;[[media:ISDH2015Gulyaev.pdf | IMAGE HOLOGRAPHY IN THE EDUCATIONAL PROCESS OF SAINTPETERSBURG POLYTECHNICAL UNIVERSITY]] : by Sergey Gulyaev (Russia) ;[[media:ISDH2015Ross.pdf | COLLECTING AND EXHIBITING HOLOGRAMS]] : by Jonathan Ross (UK) ;OPAL<nowiki>:</nowiki> THE NATURAL PHOTONIC CRYSTAL : by Francesco Mazzero == Art Concepts & Techniques == ;REFLECTIVE HOLOGRAPHY : by Maria Isabel Azevedo (Portugal), Martin Richardson (UK), Elizabeth Sandford-Richardson (UK), Luís Miguel Bernardo (Portugal), Helder Crespo (Portugal) ;RECOVERY OF EXCAVATION SCENE OF YUAN BLUE AND WHITE PORCELAIN THROUGH DIGITAL HOLOGRAPHY : by Shuo Wang, Ardeshir Osanlou, Peter Excell (UK) ;MERGING THE MATERIAL WITH THE IMMATERIAL : by Richard Bruck (USA) ;COMMUNICATING IN 3D VISIBLE LANGUAGE : by Yin-Ren Chang, Martin Richardson (UK) ;HOLOGRAPHY AS AN ARCHITECTURAL DECORATION : by Setsuko Ishii (Japan) ;[[media:ISDH2015John.pdf | AN EVALUATION OF AN ART HOLOGRAPHY EXHIBITION: SHOULD ARTISTS CARE WHAT PEOPLE THINK?]] : by Pearl John (UK) ;[[media:ISDH2015Vorzobova_Bulgakova.pdf | HOLOGRAPHIC 3-D PRINTING IN POLYMERIC MATERIALS]] : by Nadezda Vorzobova, Vera Bulgakova (Russia) ;WHAT WAS I THINKING WHEN I THOUGHT PRODUCING FOUR BY FIVE FOOT DENISYUK DCG HOLOGRAMS WAS A GOOD IDEA : by John August Muth (USA) ;HOLOGRAPHY IN DESIGN : by Ray Park, Elena Stoykova, Hoonjong Kang (South Korea) ;[[media:ISDH2015Richardson.pdf | AN INTERACTIVE HOLOGRAPHIC DISPLAY SYSTEM]] : by Martin Richardson, Vivian Suresh Kumar Amos (UK) ;HOLOGRAMS IN CAVES : by Julio Ruiz, Luis Roves (Spain) ;[[media:ISDH2015Khan.pdf | MEDICAL 3D DIGITAL HOLOGRAPHIC IMAGING FROM INDIVIDUAL ORGANS TO THE WHOLE HUMAN ANATOMY]] : by Javid Khan (UK) ;CREATING STEREOGRAMS ON AN iPhone : by Patrick Boyd (UK) ;[[media:ISDH2015Janardo.pdf | ARTISTIC HOLOGRAPHY AS A TYPOLOGY BELONGING TO THE VIRTUALLY THREE-DIMENSIONAL ARTS]] : by Nuno Miguel José Janardo (Portugal) == Recording Materials & Processing == ;[[media:ISDH2015Andreeva.pdf | DISPLAY HOLOGRAPHY AND NANOPLASMONICS]] : by Olga Andreeva (Russia) ;[[media:ISDH2015Banyasz.pdf | EFFECTS OF NONLINEARITY AND FINITE SPATIAL RESOLUTION OF SILVER HALIDE RECORDING MATERIALS ON THE RECONSTRUCTED HOLOGRAPHIC IMAGE]] : by István Bányász (Hungary) ;[[media:ISDH2015Ganzherli.pdf | HOLOGRAPHIC METHODS OF DIFFUSERS FORMATION ON SILVER HALIDE PHOTOGRAPHIC EMULSIONS]] : by Nina Ganzherli, Sergey Gulyaev, Irina Maurer, Dmitriy Chernykh (Russia) ;[[media:ISDH2015Kutanov.pdf | DIRECT LASER RECORDING OF DOT HOLOGRAMS ON AMORPHOUS SILICON FILM]] : by Askar Kutanov, Zamirgul Kazakbaeva (Kyrgyzstan) ;[[media:ISDH2015Vorzobova_Ryabova.pdf | CHARACTERISTICS OF NRC "KURCHATOV INSTITUTE" MATERIALS FOR COLOR HOLOGRAPHIC RECORDING]] : by Nadezda Vorzobova, Roze Ryabova (Russia) ;[[media:ISDH2015Gentet.pdf | RECORDING MATERIAL "ULTIMATE" FOR DISPLAY HOLOGRAPHY AND HOE's]] : by Yves Gentet (France) == Electronic, Digital & CGH == ;[[media:ISDH2015Brotherton-Ratcliffe.pdf | A MORE INTUITIVE APPROACH TO DIFFRACTION IN VOLUME OPTICAL GRATINGS AND HOLOGRAMS]] : by David Brotherton-Ratcliffe (UK) (invited) ;[[media : ISDH2015Page.pdf | VISUALIZATION OF COMPLEX MEDICAL DATA USING NEXTGENERATION HOLOGRAPHIC TECHNIQUES]] : by Michael Page (Canada) (invited) ;[[media:ISDH2015Bove.pdf | PROGRESS IN FULL-COLOR HOLOGRAPHIC DISPLAYS BASED AROUND ANISOTROPIC LEAKY-MODE MODULATORS]] : by V. Michael Bove Jr., Sundeep Jolly, Ermal Dreshaj, Nickolaos Savidis and Daniel Smalley (USA) ;[[media:ISDH2015Cheng.pdf | IMAGE FORMATION OF HOLOGRAM RECONSTRUCTION BY LIQUID CRYSTAL ON SILICON DEVICE]] : by Chau-Jern Cheng, Chung-Hsin Wu, Han-Yen Tu, Junchang Li, Jinbin Gui (Taiwan) ;[[media:ISDH2015Jia.pdf | A FAST OCCLUSION EFFECT CACULATION METHOD BY MULTIVIEW INVERSE ORTHOGRAPHIC PROJECTION IN 3D HOLOGRAPHIC DISPLAY]] : by Jia Jia, Juan Liu, Guofan Jin, Yongtian Wang (China) ;[[media:ISDH2015Morozov.pdf | INTEGRATED SOLUTION FOR HOE BASED HOLOGRAPHIC PRINTER]] : by Alexander Morozov, Andrew Putilin, Hong-Seok Lee, Vladislav Druzhin, German Dubinin, Sergey Kopenkin, Yuriy Borodin, SunIl Kim, ChilSung Choi (Russia) ;[[media:ISDH2015Kang.pdf | COLOR HOLOGRAPHIC WAVEFRONT PRINTER]] : by Hoonjong Kang, Elena Stoykova, Youngmin Kim, Sunghee Hong, Joosup Park, Jisoo Hong (South Korea) ;[[media:ISDH2015Kazempourradi.pdf | HOLOGRAPHIC IMAGE PROJECTION WITH DOUBLED FIELD OF VIEW BY HALF-PIXEL SHIFT ALIGNMENT OF TWO SPATIAL LIGHT MODULATORS]] : by Seyedmahdi Kazempourradi, Deniz Mengu, Kivanc Hedili, Erdem Ulusoy, Hakan Urey (Turkey) ;[[media:ISDH2015Khan2.pdf | A REVIEW OF DESIGN CONSIDERATIONS AND PRACTICAL IMPLEMENTATION OF 3D ELECTRO-HOLOGRAPHIC DISPLAYS]] : by Javid Khan (UK) ;[[media:ISDH2015Kim.pdf | FOURIER ZOOM-IN AND WIDE RANGE ANGULAR SPECTRUM METHOD]] : by Yong-Hae Kim, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Chi-Sun Hwang (South Korea) ;[[media:ISDH2015Kolyuchkin.pdf | THE QUALITY INSPECTION METHOD OF SECURITY HOLOGRAMS]] : by Vasily Kolyuchkin, Sergey Odinokov, Yevgeny Talalaev, Ivan Tsyganov (Russia) ;[[media:ISDH2015Zlokazov.pdf | COMPUTER-GENERATED FOURIER HOLOGRAM IN OPTICAL DEVICE OF VISUAL OBSERVATION]] : by Evgenii Zlokazov, Sergey Odinokov, Aleksandr Betin, Sergey Donchenko, Mikhail Kovalev, Vladimir Talalaev (Russia) ;[[media:ISDH2015Paraschou.pdf | EXPLOITATION OF DISPLAY HOLOGRAPHY IN MAPPING, FACING NEW CHALLENGES IN THE FIELD OF ENVIROMMENTAL PROTECTION]] : by Ch. Paraschou, A. Sarakinos, T. Alexandridis, G. Zalidis (Greece) ;[[media:ISDH2015Lobaz.pdf | DOUBLE LOOKUP TABLE METHOD FOR FAST LIGHT PROPAGATION CALCULATIONS]] : by Petr Lobaz (Czech Republic) ;[[media:ISDH2015Matsushima.pdf | NEW TECHNIQUES IN HIGH-DEFINITION COMPUTER HOLOGRAPHY]] : by Kyoji Matsushima, Yasuhiro Tsuchiyama, Noriaki Sonobe, Sumio Nakahara (Japan) ;[[media:ISDH2015Sakamoto.pdf | FAST CALCULATION OF CGH FOR RECTANGULAR PATCH MODEL]] : by Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara (Japan) ;[[media:ISDH2015Yoshikawa.pdf | IMAGE QUALITY EVALUATION OF A COMPUTER-GENERATED PHASE HOLOGRAM]] : by Hiroshi Yoshikawa, Takeshi Yamaguchi (Japan) ;[[media:ISDH2015Zhang.pdf | COMPUTER-GENERATED HOLOGRAM BASED ON LAYERED HOLOGRAPHIC STEREOGRAM]] : by Hao Zhang , Yan Zhao, Liangcai Cao, Guofan Jin (China) ;[[media:ISDH2015Zhao.pdf | DISPLAY AND MEASUREMENT OF COMPLEX FLOW FIELDS BY USING DIGITAL HOLOGRAPHIC INTERFEROMETRY]] : by Jianlin Zhao, Jianglei Di, Jun Wang, Bingjing Wu (China) == Technical Applications == ;[[media:ISDH2015GaoHongyue.pdf | REAL-TIME DYNAMIC HOLOGRAPHIC DISPLAY IN SUPER-FAST LIQUID CRYSTALS TO FUTURE HOLOGRAPHIC 3D TV]] : by Hongyue Gao, Jicheng Liu, Chao Zeng, Yingjie Yu, Huadong Zheng (China) (invited) ;[[media:ISDH2015Parker.pdf | HOLOGRAPHIC PHOTOMASKS FOR "GREEN" MICROLITHOGRAPHY]] : by William Parker, Julie Parker (USA) (invited) ;[[media:ISDH2015Rastogi.pdf | ADVANCES IN MULTI-DIMENSIONAL DISPLACEMENT MEASUREMENT USING HOLOGRAPHIC INTERFEROMETRY]] : by Pramod Rastogi (Switzerland) (invited) ;HOLOGRAPHIC LINEAR ANGLE NANO MEASURING SYSTEMS : by Turukhano B., Turukhano N. (Russia) ;[[media:ISDH2015Wesly.pdf | PULSED LASER HOLOGRAPHY SIMPLIFIED BY DIGITAL PHOTOGRAPHY]] : by Ed Wesly (USA) ;[[media:ISDH2015Chiu.pdf | HOLOGRAPHIC FLOATING IMAGING SYSTEM WITH LCOS SLM AND LED RECONSTRUCTION LIGHT SOURCE]] : by Po-Sheng Chiu, Cheng-Huan Chen (Taiwan) ;IMPROVING THE RECORDING CHARACTERISTICS OF DIFFRACTION GRATINGS IN THE DOT MATRIX HOLOGRAMS : by Akylbek Jeenbekov, K. Zhumaliev, V.Redkorechev (Kyrgyzstan) ;[[media:ISDH2015Tornari.pdf | HOLOGRAPHY FRINGE PATTERNS: SYSTEMS AND APPLICATIONS IN THE STRUCTURAL DIAGNOSIS, DOCUMENTATION AND DISPLAY OF WORKS OF ART]] : by Vivi Tornari, Anastasia Tsigarida, Varvara Ziampaka (Greece) ;[[media:ISDH2015Dyomin.pdf |AUTOMATION THE PROCESS OF CREATION A VIDEO FROM A TIME SEQUENCE OF DIGITAL HOLOGRAMS OF PARTICLES]] : by Victor Dyomin, Denis Kamenev (Russia) ;[[media:ISDH2015Burunkova.pdf | GOLD - ACRYLATE NANOCOMPOSITE AS MATERIAL FOR HOLOGRAPHIC RECORDING]] : by Julia Burunkova, Igor Denisyuk, Dmitry Zhuk (Russia) ;[[media:ISDH2015Osanlou.pdf | HOLOGRAPHIC COLOUR IMAGES OF POTTED ANATOMICAL HUMAN SPECIMENS FOR MEDICAL STUDIES]] : by Ardeshir Osanlou, John Delieu, Peter Crosby, Rostam Osanlou, Emma Osanlou, Orod Osanlou (UK) ;[[media:ISDH2015Ryu.pdf | OPTICAL DESIGN OF HOLOGRAM OPTICAL ELEMENT-BASED SEETHROUGH GLASSES]] : by Jaeyeol Ryu, Dmitry Piskunov, Mikhail Popov, Nikolay Muravyev (Russia) ;[[media:ISDH2015Druzhin.pdf | HOLOGRAPHIC SEE-THROUGH HEAD-MOUNTED DISPLAY]] : by Vladislav Druzhin, Aleksander Morozov, Andrew Putilin, E.G. Malinovskaya (Russia) ;[[media:ISDH2015Zherdev.pdf | PLASMONIC SPECTRAL FILTERS BASED ON ONE-DIMENSIONAL PERIODIC STRUCTURES ]] : by Alexander Zherdev, Sergey Odinokov, Dmitriy Lushnikov, Maria Ruchkina, Evgeni Bezus, Leonid Doskolovich, Andrey Smirnov (Russia) ;[[media:ISDH2015GaoQiankun.pdf">3D OPTICAL INTENSITY MODULATION ON CURVED SURFACES BY OPTIMIZATION METHOD AND ITS APPLICATION TO FABRICATE ARBITRARY PATTERNS]] : by Qiankun Gao, Ran Tian, Xugang Wang, Juan Liu, Jian Han, Nannan Zhang, Xin Li, Bin Hu, Yongtian Wang (China) == Color Holography == ;[[media:ISDH2015Bjelkhagen.pdf | ULTRA-REALISTIC IMAGING AND OPTOCLONES]] : by Hans Bjelkhagen (UK) ;ULTIMATE FULL-PARALLAX NATURAL LIGHT HOLOGRAPHY : by Michael Finegan, Yves Gentet, Franck Randriamanana (Ireland) ;[[media:ISDH2015Lembessis.pdf | THE "F" ADVENTURE]] : by Alkis Lembessis, Andreas Sarakinos (Greece) ;[[media:ISDH2015Odinokov.pdf | EXPERIMENTAL STUDY OF THE METHOD OF RECORDING COLOR VOLUME HOLOGRAPHIC OF STEREOGRAMS ON DIFFERENT PHOTOSENSITIVE MATERIALS ON THE BASE OF THE DIFFUSER WITH A NARROW INDICATRIX OF LASER RADIATION]] : by Sergey Odinokov, Dmitry Lushnikov, Vladimir Markin, Alexander Zherdev, Ivan Tsyganov, Andrey Smirnov (Russia) ;METHOD TO MEASURE COLOR REPRODUCTION IN REFLECTION HOLOGRAMS BASED ON A CMOS RGB CAMERA : by Natalith Palacios Ortega, Daniel Velasquez (Colombia) ;[[media:ISDH2015Shevtsov_Gentet.pdf | 20-YEARS PATH TO PERFECTION: THE LATEST ACHIEVEMENTS IN COLOR HOLOGRAPHY]] : by Michael Shevtsov, Yves Gentet (Russia) ;[[media:ISDH2015Sarakinos.pdf | IN SITU RECORDING AND DISPLAYING TRUE COLOR HOLOGRAPHIC OPTICAL CLONES (OPTOCLONES©) OF CULTURAL ARTIFACTS IN MUSEUMS]] : by Andreas Sarakinos, Alkis Lembessis (Greece) ;[[media:ISDH2015Stock.pdf | NEXT-GENERATION VISIBLE LASERS FOR HOLOGRAPHY]] : by Michelle Stock, Peter Andersen, Peter Skovgaard (USA) ;[[media:ISDH2015Shevtsov.pdf | MOBILE PULSE HOLOGRAPHIC CAMERA GREEF AND ITS APPLICATION IN CULTURE AND EDUCATION]] : by Michael Shevtsov (Russia) ;[[media:ISDH2015Yuan.pdf | MAKING ANALOGUE COLOUR HOLOGRAMS AT HOME LABORATORY: LESSONS FROM FAILURE AND SUCCESS]] : by Quan Yuan (China) == The Business of Holography == ;[[media:ISDH2015Fan.pdf | DEMONSTRATION OF PERFECT HOLOGRAPHIC DISPLAY ON COMMERCIAL 4K PLANE DISPLAYER]] : by Frank Fan, Sam Choi, Chaochuan Jiang (China) (invited) ;STRIVING TO MAKE A LIVING WITH 3D IMAGES<nowiki>:</nowiki> QUITE A CHALLENGE... : by Pascal Gauchet (France) ;[[media:ISDH2015Beryozkina.pdf | SLAVICH HOLOGRAPHIC MATERIALS]] : by Juliay Beryozkina (Russia) ;[[media:ISDH2015Souparis1.pdf | FROM A START-UP OF THE 80’S TO A MATURE BUSINESS IN HOLOGRAPHY:THE STORY OF HOLOGRAM INDUSTRIES]] : by Hugues Souparis (France) ;[[media:ISDH2015Souparis2.pdf | THE HOLOGRAM FOUNDATION: PROMOTING HOLOGRAPHY AS A COLLECTABLE ART]] : by Hugues Souparis (France) ;REFLECTION VOLUME HOLOGRAPHY: WHERE THE BUSINESS OF BRAND AND PRODUCT SECURITY CAN BE BOTH POSITIVE AND BEAUTIFUL : by Tim Sandford ;SCIENCE-INTENSIVE, HIGH-TECH ENTERPRISE CJSC "HOLOGRAPHY INDUSTRY" - AN EXAMPLE OF PUBLIC AND PRIVATE PARTNERSHIP IN THE FIELD OF ANTI-COUNTERFEITING TECHNOLOGY OF DOCUMENTS, SECURITIES AND PRODUCTS BASED ON HOLOGRAPHY IN THE REPUBLIC OF BELARUS : by Leonid Tanin == Youth Session, Workshop == ;RECORDING OF DISPLAY HOLOGRAMS BY YU. N. DENISYUK'S METHOD : by Nataliy Andreeva (Russia) ;[[media:ISDH2015Escarguel.pdf | UPGRADE OF THE PEDAGOGIC/POPULAR SCIENCE TOOL FOR HOLOGRAPHY: THE COLOR HOLOGRAPHY KIT]] : by Alexandre Escarguel (France) ;DIGITAL HOLOGRAPHIC RECORDING OF PLANKTON : by Victor Dyomin (Russia) ;HOLOGRAPHIC INTERFEROMETRY OF TRANSPARENT MEDIA DURING THE ACTION OF HEAT SOURCES : by Boris Manukhin (Russia) ;RECORDING OF HIGH-SELECTIVITY HOLOGRAM OPTICAL ELEMENT : by Paramonov Alexandr (Russia) ;SIMULATION OF WAVEFRONT PROPAGATION : by Nikolay Petrov (Russia) 4976c06c92b6a1648330699eac89f57e9b410882 0 1 2704 2634 2015-07-19T13:14:26Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org</big>'''<br />A place to discuss holography |} '''http://holographyforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from '''[[ISDH 2015 | the 10th International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 252d7b6acaf5ca3debb4d05d3f62d24b5511b253 2707 2704 2015-07-19T15:15:27Z Jsfisher 1 /* New Stuff and Recent Additions */ wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://www.holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org</big>'''<br />A place to discuss holography |} '''http://holographyforum.org/forum''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 78ec16812247c4c85f85225da30b7be7a2444903 2712 2707 2015-08-08T20:53:26Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holowiki.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="400em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] be77edcabb25966668e84084c038f715038a113f 2713 2712 2015-08-08T20:53:51Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holowiki.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 1f623f40560799fccd59ee0999a2115f4f60445a 2714 2713 2015-08-09T15:05:37Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} {{note | If you are looking for the Holography Forum, click --> '''[http://holowiki.org/forum here]''' <-- | error}} '''<big>Welcome to the [http://holowiki.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] ad49110161a07371a0a6949728a99e261fc03585 2715 2714 2015-08-10T20:45:52Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} {{note | If you are looking for the Holography Forum, click --> '''[http://holowiki.org/forum here]''' <-- | error}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] be2bc9b2647d95961bdeed8e41a98a97923e9088 6 1288 2705 2015-07-19T15:13:33Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1289 2706 2015-07-19T15:14:43Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1290 2708 2015-07-19T15:15:47Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1291 2709 2015-07-19T15:17:17Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 279 2716 1945 2015-08-16T01:58:42Z Jsfisher 1 /* Spatial Frequency */ wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== <math>\displaystyle f = \frac{sin{\theta_1} - sin{\theta_2}}{\lambda}</math> Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: [[Image:SpatialEQ.gif]] (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say. (while I nodded off!) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html [[Image:DiffractionEQ.gif]] They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) [[Image:EdExample1.gif]] Just like it should. If we repeat the above but with m = 2, we get: [[Image:EdExample2.gif]] Unh-unh! sin of an angle can’t be >1! (This is called a [[http://en.wikipedia.org/wiki/Evanescent_wave evanescent]] wave and is not propegated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) [[Image:EdExample3.gif]] (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: [[Image:EdExample4.gif]] Replacing m by 2, [[Image:EdExample5.gif]] When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm [[Image:EdExample6.gif]] Replacing m by 2, [[Image:EdExample7.gif]] This time we can get away by replacing m by 3, [[Image:EdExample8.gif]] So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== f4dc55266312a3860c7299059ac6562c121b3f2e 2717 2716 2015-08-16T02:02:10Z Jsfisher 1 /* Spatial Frequency */ wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== <math>\displaystyle f = \frac{sin(\theta_1) - sin(\theta_2)}{\lambda}</math> Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: <math>\displaystyle d = \frac{\lambda}{sin(\theta_1) - sin(\theta_2)}</math> (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say. (while I nodded off!) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html [[Image:DiffractionEQ.gif]] They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) [[Image:EdExample1.gif]] Just like it should. If we repeat the above but with m = 2, we get: [[Image:EdExample2.gif]] Unh-unh! sin of an angle can’t be >1! (This is called a [[http://en.wikipedia.org/wiki/Evanescent_wave evanescent]] wave and is not propegated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) [[Image:EdExample3.gif]] (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: [[Image:EdExample4.gif]] Replacing m by 2, [[Image:EdExample5.gif]] When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm [[Image:EdExample6.gif]] Replacing m by 2, [[Image:EdExample7.gif]] This time we can get away by replacing m by 3, [[Image:EdExample8.gif]] So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== 644b0956942371bc8eef1c2d024b4975f9113a10 2718 2717 2015-08-16T02:38:01Z Jsfisher 1 /* Diffraction */ wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== <math>\displaystyle f = \frac{sin(\theta_1) - sin(\theta_2)}{\lambda}</math> Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: <math>\displaystyle d = \frac{\lambda}{sin(\theta_1) - sin(\theta_2)}</math> (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say. (while I nodded off!) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html :: <math>\sin{\theta_{out}} = \sin{\theta_{in}} + m \lambda f</math> They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) :: <math>\sin{\theta_{out}} = \sin{(-40)} + 1 (0.00033nm) (1805 c/mm)</math> :: <math>\sin{\theta_{out}} = -0.643 + 1.143</math> :: <math>\sin{\theta_{out}} = 0.500</math> :: <math>\theta_{out} = 30^\circ</math> Just like it should. If we repeat the above but with m = 2, we get: :: <math>\sin{\theta_{out}} = \sin{(-40)} + 2 (0.00033nm) (1805 c/mm)</math> :: <math>\sin{\theta_{out}} = -0.643 + 2.286</math> :: <math>\sin{\theta_{out}} = 1.643</math> Unh-unh! sin of an angle can’t be >1! (This is called a [http://en.wikipedia.org/wiki/Evanescent_wave evanescent] wave and is not propagated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) :: <math>f = \frac{\sin{10} - \sin{(-10)}}{633nm}</math> :: <math>f = 548.651...</math> (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: :: <math>\sin{\theta_{out}} = m \lambda f</math> :: <math>\sin{\theta_{out}} = 1 (.000633nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.34815</math> :: <math>\theta_{out} = 20.37^\circ</math> Replacing m by 2, :: <math>\sin{\theta_{out}} = 2 (.000633nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.6963</math> :: <math>\theta_{out} = 44.1^\circ</math> When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm :: <math>\sin{\theta_{out}} = 1 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.2413</math> :: <math>\theta_{out} = 14.0^\circ</math> Replacing m by 2, :: <math>\sin{\theta_{out}} = 2 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.4826</math> :: <math>\theta_{out} = 29^\circ</math> This time we can get away by replacing m by 3, :: <math>\sin{\theta_{out}} = 3 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.7293</math> :: <math>\theta_{out} = 46^\circ</math> So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== 937c0f4e0a861c07a1aa1519a4c50ee488451fc4 2719 2718 2015-08-16T02:38:38Z Jsfisher 1 /* Spatial Frequency */ wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== :: <math>\displaystyle f = \frac{sin(\theta_1) - sin(\theta_2)}{\lambda}</math> Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: :: <math>\displaystyle d = \frac{\lambda}{sin(\theta_1) - sin(\theta_2)}</math> (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say. (while I nodded off!) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html :: <math>\sin{\theta_{out}} = \sin{\theta_{in}} + m \lambda f</math> They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) :: <math>\sin{\theta_{out}} = \sin{(-40)} + 1 (0.00033nm) (1805 c/mm)</math> :: <math>\sin{\theta_{out}} = -0.643 + 1.143</math> :: <math>\sin{\theta_{out}} = 0.500</math> :: <math>\theta_{out} = 30^\circ</math> Just like it should. If we repeat the above but with m = 2, we get: :: <math>\sin{\theta_{out}} = \sin{(-40)} + 2 (0.00033nm) (1805 c/mm)</math> :: <math>\sin{\theta_{out}} = -0.643 + 2.286</math> :: <math>\sin{\theta_{out}} = 1.643</math> Unh-unh! sin of an angle can’t be >1! (This is called a [http://en.wikipedia.org/wiki/Evanescent_wave evanescent] wave and is not propagated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) :: <math>f = \frac{\sin{10} - \sin{(-10)}}{633nm}</math> :: <math>f = 548.651...</math> (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: :: <math>\sin{\theta_{out}} = m \lambda f</math> :: <math>\sin{\theta_{out}} = 1 (.000633nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.34815</math> :: <math>\theta_{out} = 20.37^\circ</math> Replacing m by 2, :: <math>\sin{\theta_{out}} = 2 (.000633nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.6963</math> :: <math>\theta_{out} = 44.1^\circ</math> When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm :: <math>\sin{\theta_{out}} = 1 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.2413</math> :: <math>\theta_{out} = 14.0^\circ</math> Replacing m by 2, :: <math>\sin{\theta_{out}} = 2 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.4826</math> :: <math>\theta_{out} = 29^\circ</math> This time we can get away by replacing m by 3, :: <math>\sin{\theta_{out}} = 3 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.7293</math> :: <math>\theta_{out} = 46^\circ</math> So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== f2c5529f9e3fe81bf491ee8ed51bb72887b93d16 6 1292 2720 2015-08-19T18:39:05Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 424 2721 1935 2015-08-19T18:39:41Z Jsfisher 1 wikitext text/x-wiki [[Image:Lcross.jpg]] Lloyd Gerald Cross, world-renowned physicist and holographer, died peacefully at his home in Point Arena, California on April 28, 2015 at the age of eighty. Lloyd was born in Flint, Michigan to a working class family of autoworkers and his life reflected in many ways the development of American society in the late 20th century. The first of his family to attend college, he became at a young age a leading member of teams designing and implementing innovative technology as a part of the Science push of the 1960s. His work with lasers led him to co-found Trion Instruments, one of the first companies commercially producing lasers for research and commercial use in the world. He was an early pioneer of laser light show technologies, claiming the world’s first laser light show performance in New York in the late sixties. However, rather than amass a fortune like latter-day entrepreneurs, Lloyd rejected the simplistic use of technology for military and purely commercial activities. Working with artists during the heyday of the counter-culture movement, he turned away from business to develop economically viable ways to use the new technologies that would be accessible to everyone. For example, in a period in which making holograms required massive steel beds for stability, both incredibly expensive and cumbersome to use, he co-developed a simple “sand box” design that floated a large wooden box filled with sand over inner tubes, creating a platform that was both economical and versatile. His designs, which he freely shared, allowed him to set up the School of Holography in San Francisco and helped a whole generation of scientists and artists to immerse themselves in this new medium. Lloyd also invented the technique of creating “multiplex” holograms that made moving three-dimensional images from movie reels, a technique used in the science fiction movie Logan’s Run. Continuing with the counter culture theme, Lloyd developed a number of innovative ways in which to harness solar power using inexpensive materials and tools. For example, he developed a powerful solar power concentrator using pine boards, paste, a kitchen roller, 6 inch nails, and aluminum foil that could turn water running through a pipe into steam within seconds. Another device using curved Plexiglas mirrors could focus solar power into a point capable of melting copper. In 1980, Lloyd moved to Point Arena, California, where he continued his innovative work, and where he became a beloved and respected member of the community. He is survived by his loving wife Cecil, children Lloyd, Elizabeth, John and Jennifer, grandson John Cuauhtemoc, great-granddaughters Xochitl and Elena, sister Arlene, and numerous friends and colleagues. Lloyd will always be remembered by those whose lives he touched for a mind that constantly brimmed, right up to his last days, with scientific, social, artistic, domestic and comedic creativity. [[File:olderLlyodCross.jpg|400px]] 32fc2f9321f8b8c4a9732f871a30dc8b65e847f1 2722 2721 2015-08-19T18:40:40Z Jsfisher 1 wikitext text/x-wiki [[Image:Lcross.jpg]] Lloyd Gerald Cross, world-renowned physicist and holographer, died peacefully at his home in Point Arena, California on April 28, 2015 at the age of eighty. Lloyd was born in Flint, Michigan to a working class family of autoworkers and his life reflected in many ways the development of American society in the late 20th century. The first of his family to attend college, he became at a young age a leading member of teams designing and implementing innovative technology as a part of the Science push of the 1960s. His work with lasers led him to co-found Trion Instruments, one of the first companies commercially producing lasers for research and commercial use in the world. He was an early pioneer of laser light show technologies, claiming the world’s first laser light show performance in New York in the late sixties. However, rather than amass a fortune like latter-day entrepreneurs, Lloyd rejected the simplistic use of technology for military and purely commercial activities. Working with artists during the heyday of the counter-culture movement, he turned away from business to develop economically viable ways to use the new technologies that would be accessible to everyone. For example, in a period in which making holograms required massive steel beds for stability, both incredibly expensive and cumbersome to use, he co-developed a simple “sand box” design that floated a large wooden box filled with sand over inner tubes, creating a platform that was both economical and versatile. His designs, which he freely shared, allowed him to set up the School of Holography in San Francisco and helped a whole generation of scientists and artists to immerse themselves in this new medium. Lloyd also invented the technique of creating “multiplex” holograms that made moving three-dimensional images from movie reels, a technique used in the science fiction movie Logan’s Run. Continuing with the counter culture theme, Lloyd developed a number of innovative ways in which to harness solar power using inexpensive materials and tools. For example, he developed a powerful solar power concentrator using pine boards, paste, a kitchen roller, 6 inch nails, and aluminum foil that could turn water running through a pipe into steam within seconds. Another device using curved Plexiglas mirrors could focus solar power into a point capable of melting copper. In 1980, Lloyd moved to Point Arena, California, where he continued his innovative work, and where he became a beloved and respected member of the community. He is survived by his loving wife Cecil, children Lloyd, Elizabeth, John and Jennifer, grandson John Cuauhtemoc, great-granddaughters Xochitl and Elena, sister Arlene, and numerous friends and colleagues. Lloyd will always be remembered by those whose lives he touched for a mind that constantly brimmed, right up to his last days, with scientific, social, artistic, domestic and comedic creativity. [[File:olderLlyodCross.jpg|400px]] 7f99b0c20628fd023e2115783a1d74db41c6c301 0 193 2723 2582 2015-08-19T18:41:58Z Jsfisher 1 wikitext text/x-wiki [[Image:Colink.jpg]] Colin Kaminski is an amateur holographer who in a state of extreme frustration and needing advice started the forum that has become the [http://www.holowiki.org/forum Holography Forum] and then this Wiki. He really has no other holography related accomplishments other than about 100 or so 4x5" and smaller holograms given to children. He has worked as an Assembly Language Programmer, Motorcycle Mechanic, Luthier, Theatrical Lighting Designer, Product Designer and now he is the Master Brewer at [http://www.downtownjoes.com Downtown Joe's] in Napa, CA. [http://www.designerinlight.com Colin Kaminski's Web Site] [[Image:Colinemail.gif]] 0374888db7234e6d3f49cf22e0c5c61f9ee4da6e 0 424 2724 2722 2015-08-19T18:43:27Z Jsfisher 1 wikitext text/x-wiki [[Image:Lcross.jpg]] == Obituary == Lloyd Gerald Cross, world-renowned physicist and holographer, died peacefully at his home in Point Arena, California on April 28, 2015 at the age of eighty. Lloyd was born in Flint, Michigan to a working class family of autoworkers and his life reflected in many ways the development of American society in the late 20th century. The first of his family to attend college, he became at a young age a leading member of teams designing and implementing innovative technology as a part of the Science push of the 1960s. His work with lasers led him to co-found Trion Instruments, one of the first companies commercially producing lasers for research and commercial use in the world. He was an early pioneer of laser light show technologies, claiming the world’s first laser light show performance in New York in the late sixties. However, rather than amass a fortune like latter-day entrepreneurs, Lloyd rejected the simplistic use of technology for military and purely commercial activities. Working with artists during the heyday of the counter-culture movement, he turned away from business to develop economically viable ways to use the new technologies that would be accessible to everyone. For example, in a period in which making holograms required massive steel beds for stability, both incredibly expensive and cumbersome to use, he co-developed a simple “sand box” design that floated a large wooden box filled with sand over inner tubes, creating a platform that was both economical and versatile. His designs, which he freely shared, allowed him to set up the School of Holography in San Francisco and helped a whole generation of scientists and artists to immerse themselves in this new medium. Lloyd also invented the technique of creating “multiplex” holograms that made moving three-dimensional images from movie reels, a technique used in the science fiction movie Logan’s Run. Continuing with the counter culture theme, Lloyd developed a number of innovative ways in which to harness solar power using inexpensive materials and tools. For example, he developed a powerful solar power concentrator using pine boards, paste, a kitchen roller, 6 inch nails, and aluminum foil that could turn water running through a pipe into steam within seconds. Another device using curved Plexiglas mirrors could focus solar power into a point capable of melting copper. In 1980, Lloyd moved to Point Arena, California, where he continued his innovative work, and where he became a beloved and respected member of the community. He is survived by his loving wife Cecil, children Lloyd, Elizabeth, John and Jennifer, grandson John Cuauhtemoc, great-granddaughters Xochitl and Elena, sister Arlene, and numerous friends and colleagues. Lloyd will always be remembered by those whose lives he touched for a mind that constantly brimmed, right up to his last days, with scientific, social, artistic, domestic and comedic creativity. [[File:olderLlyodCross.jpg|400px]] 82fdcabc281a2e2d69e774fd8454c6de770d4503 0 1 2725 2715 2015-08-31T23:53:55Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} {{note | Cecil Cross, wife to Lloyd Cross, invites everyone to a celebration of Lloyd's life and accomplishments Monday, September 7, 2015. As many of you know, Lloyd passed away April 28 of this year, leaving a legacy of achievement in laser physics and holography. A re-posting of his obituary can found here: http://holographyforum.org/forum/viewtopic.php?f=12&t=1046&p=67310#p67310. The celebration is from 3pm to 7pm at Cecil and Lloyd's home, 38991 Eureka Hill Road, Point Arena. The setting in Northern California is quite attractive, and an exploration of Lloyd's lab and his projects and the company of others in attendance will make it well worth the trip. All are welcome to attend -- family, friends, holographers, and even those just curious about holography. | error}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 7e94dd93db00b2460093a5d8c57d428534532d55 2726 2725 2015-09-01T00:05:24Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Special Announcement:</big>'''<br><big>Cecil Cross, wife to Lloyd Cross, invites everyone to a celebration of Lloyd's life and accomplishments Monday, September 7, 2015.</big> <big>As many of you know, Lloyd passed away April 28 of this year, leaving a legacy of achievement in laser physics and holography. A re-posting of his obituary can found here: http://holographyforum.org/forum/viewtopic.php?f=12&t=1046&p=67310#p67310.</big> <big>The celebration is from 3pm to 7pm at Cecil and Lloyd's home, 38991 Eureka Hill Road, Point Arena. The setting in Northern California is quite attractive, and an exploration of Lloyd's lab and his projects and the company of others in attendance will make it well worth the trip. All are welcome to attend -- family, friends, holographers, and even those just curious about holography.</big> <br> '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 43e2eb3b8b2d8ecc1b6150c0f16b0f40ab6c994c 2727 2726 2015-09-08T01:23:42Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 2d2a6e690b74d3abd5c28819e0b437da0c2c37d5 2747 2727 2016-05-17T02:03:02Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} {{note | '''Notice of temporary service interruptions''' <br> Beginning Tuesday, May 31, 2016, there will be a sequence of service interruptions. At approximately 5:00pm EDT (GMT - 5:00) on Tuesday, Wednesday, and Thursday, service will be interrupted each day for approximately 5 to 15 minutes. On Friday, June 3, 2016, the interruption will be substantially longer. The maintenance is scheduled to run from 1:00pm until 2:00am Saturday (13 hours). Both the Holography Forum and the Holo Wiki site are impacted. I apologize for any inconvenience this may cause. | gotcha }} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 7aef9db9ffbd5e8857078efb9011493cf306c114 2748 2747 2016-05-17T13:35:50Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} {{note | '''Notice of temporary service interruptions''' <br> Beginning Tuesday, May 31, 2016, there will be a sequence of service interruptions. At approximately 5:00pm EDT (GMT - 4:00) on Tuesday, Wednesday, and Thursday, service will be interrupted each day for approximately 5 to 15 minutes. On Friday, June 3, 2016, the interruption will be substantially longer. The maintenance is scheduled to run from 1:00pm until 2:00am Saturday (13 hours). Both the Holography Forum and the Holo Wiki site are impacted. I apologize for any inconvenience this may cause. | gotcha }} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 2a281ae8ba38a7546f947e95062641aac9f907f7 2750 2748 2016-06-04T02:04:27Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 2d2a6e690b74d3abd5c28819e0b437da0c2c37d5 2756 2750 2017-06-30T22:40:28Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} {{ Note | '''Notice: Scheduled Service Interruptions''' On each of July 5, 6, and 7 (Wednesday through Friday) there may be service interruptions to both the Holography Forum and the Wiki. The time scheduled for these interruptions is 4:30 pm - 9:30 pm Eastern Daylight Time (GMT - 4:00). I apologize for the inconvenience this may cause | error}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 4981173184dc1a17cf0b8922d4101742bccb620e 2757 2756 2017-07-07T16:30:40Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} {{ Note | '''UPDATED Notice: Scheduled Service Interruptions''' All necessary work was completed ahead of schedule. The service interruption planned for Friday, July 7 has been canceled. | error}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] ac60c55f155adf4716d222daafd18fab85ff6cd1 2758 2757 2017-07-07T16:30:57Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} {{ Note | '''UPDATED Notice: Scheduled Service Interruptions''' All necessary work was completed ahead of schedule. The service interruption planned for Friday, July 7 has been canceled. | error}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 34fc1605912872b9956964b5f75931b117c16f3b 2759 2758 2017-07-07T16:33:07Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic }} {{ Note | '''UPDATED Notice: Scheduled Service Interruptions''' <br> All necessary work was completed ahead of schedule. The service interruption planned for Friday, July 7 has been canceled. | error}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 085e1c3d6285773e11ff20655b7b6f2b35b0b58c 2760 2759 2017-07-08T02:12:26Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] dc9be7acaa8e989ab81d72704600e3f7b0248c8d 2761 2760 2018-06-27T13:41:12Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] {{note|'''Scheduled Service Interruptions''' Due to maintenance work scheduled for the first week of July, availability of both the Holography Forum and the Wiki may be interrupted. Here is the date, time, and likely duration for each the service interruption. July 2 between 4:00 and 6:00pm for somewhere between 5 and 60 minutes July 3 between 4:00 and 6:00pm for somewhere between 5 and 120 minutes July 5 between 4:00 and 6:00pm for somewhere between 5 and 60 minutes All times are US Eastern Daylight Time (UTC - 4:00).|gotcha}} == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 64e91dd9486ed690fc62441ba75f84c387550bed 2762 2761 2018-06-27T13:41:45Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] {{note|'''Scheduled Service Interruptions''' Due to maintenance work scheduled for the first week of July, availability of both the Holography Forum and the Wiki may be interrupted. Here is the date, time, and likely duration for each the service interruption. * July 2 between 4:00 and 6:00pm for somewhere between 5 and 60 minutes * July 3 between 4:00 and 6:00pm for somewhere between 5 and 120 minutes * July 5 between 4:00 and 6:00pm for somewhere between 5 and 60 minutes All times are US Eastern Daylight Time (UTC - 4:00).|gotcha}} == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] cafc4dbc6de4b8109757ca63907a12f9816c565f 2763 2762 2018-06-27T20:49:02Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] {{note|'''Scheduled Service Interruptions''' Due to maintenance work scheduled for the first week of July, availability of both the Holography Forum and the Wiki may be interrupted. Here are the dates, time, and likely durations of the service interruptions. * July 2 between 4:00 and 6:00pm for somewhere between 5 and 60 minutes * July 3 between 4:00 and 6:00pm for somewhere between 5 and 120 minutes * July 5 between 4:00 and 6:00pm for somewhere between 5 and 60 minutes All times are US Eastern Daylight Time (UTC - 4:00).|gotcha}} == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] e2c50abb921f1ff176aec4633f004d11894c3cc8 2764 2763 2018-07-03T00:47:16Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} {{note|'''Scheduled Service Interruptions''' Due to maintenance work scheduled for the first week of July, availability of both the Holography Forum and the Wiki may be interrupted. Here are the dates, time, and likely durations of the service interruptions. * July 2 between 4:00 and 6:00pm for somewhere between 5 and 60 minutes -- Done * July 3 between 4:00 and 6:00pm for somewhere between 5 and 120 minutes * July 5 between 4:00 and 6:00pm for somewhere between 5 and 60 minutes All times are US Eastern Daylight Time (UTC - 4:00).|gotcha}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 7d3c3fc9114a11c3985f25434b09dc21918962f0 2765 2764 2018-07-04T19:13:58Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} {{note|'''Scheduled Service Interruptions''' Due to maintenance work scheduled for the first week of July, availability of both the Holography Forum and the Wiki may be interrupted. Here are the dates, time, and likely durations of the service interruptions. * July 2 between 4:00 and 6:00pm for somewhere between 5 and 60 minutes -- Done * July 3 between 4:00 and 6:00pm for somewhere between 5 and 120 minutes -- Done * July 5 between 4:00 and 6:00pm for somewhere between 5 and 60 minutes All times are US Eastern Daylight Time (UTC - 4:00).|gotcha}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] e890fbf6c88994f74f06c67138d161e0a05837b4 2766 2765 2018-07-05T23:52:24Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [http://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=http://www.holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[http://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] dc9be7acaa8e989ab81d72704600e3f7b0248c8d 2768 2766 2018-07-18T01:45:29Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [https://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=https://holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} '''[https://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] d800b004d385d8edc9d26f63acd7cce1def170ed 2771 2768 2019-02-23T01:59:26Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [https://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=https://holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} {{note|'''Temporary Outage Scheduled:''' Saturday, March 2, 2019, the Holography Forum and the Wiki will be unavailable beginning approximately 8:00am EST (1:00pm UTC) for up to 16 hours. This is due to some overdue electrical work. (While my hosting provider for the forum and wiki has been very generous over the years providing Internet connectivity at no cost, the generosity never included backup power.) I apologize for the inconvenience this outage may cause.|gotcha}} '''[https://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 57c06b1347c53ca0d6c1a264dc19af3801a1a064 2772 2771 2019-03-03T03:14:12Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [https://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=https://holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} <!--{{note|'''Temporary Outage Scheduled:''' Saturday, March 2, 2019, the Holography Forum and the Wiki will be unavailable beginning approximately 8:00am EST (1:00pm UTC) for up to 16 hours. This is due to some overdue electrical work. (While my hosting provider for the forum and wiki has been very generous over the years providing Internet connectivity at no cost, the generosity never included backup power.) I apologize for the inconvenience this outage may cause.|gotcha}}--> '''[https://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] d87c12ed9d13b48973991e42c3780470f6c6956c 0 279 2728 2719 2015-10-31T21:01:35Z Jsfisher 1 /* Introduction */ wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. ('''Update:''' Courtesy of the author, Stephen McGrew: [http://nli-ltd.com/publications/graphical_method.php]) Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== :: <math>\displaystyle f = \frac{sin(\theta_1) - sin(\theta_2)}{\lambda}</math> Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: :: <math>\displaystyle d = \frac{\lambda}{sin(\theta_1) - sin(\theta_2)}</math> (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say. (while I nodded off!) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html :: <math>\sin{\theta_{out}} = \sin{\theta_{in}} + m \lambda f</math> They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) :: <math>\sin{\theta_{out}} = \sin{(-40)} + 1 (0.00033nm) (1805 c/mm)</math> :: <math>\sin{\theta_{out}} = -0.643 + 1.143</math> :: <math>\sin{\theta_{out}} = 0.500</math> :: <math>\theta_{out} = 30^\circ</math> Just like it should. If we repeat the above but with m = 2, we get: :: <math>\sin{\theta_{out}} = \sin{(-40)} + 2 (0.00033nm) (1805 c/mm)</math> :: <math>\sin{\theta_{out}} = -0.643 + 2.286</math> :: <math>\sin{\theta_{out}} = 1.643</math> Unh-unh! sin of an angle can’t be >1! (This is called a [http://en.wikipedia.org/wiki/Evanescent_wave evanescent] wave and is not propagated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) :: <math>f = \frac{\sin{10} - \sin{(-10)}}{633nm}</math> :: <math>f = 548.651...</math> (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: :: <math>\sin{\theta_{out}} = m \lambda f</math> :: <math>\sin{\theta_{out}} = 1 (.000633nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.34815</math> :: <math>\theta_{out} = 20.37^\circ</math> Replacing m by 2, :: <math>\sin{\theta_{out}} = 2 (.000633nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.6963</math> :: <math>\theta_{out} = 44.1^\circ</math> When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm :: <math>\sin{\theta_{out}} = 1 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.2413</math> :: <math>\theta_{out} = 14.0^\circ</math> Replacing m by 2, :: <math>\sin{\theta_{out}} = 2 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.4826</math> :: <math>\theta_{out} = 29^\circ</math> This time we can get away by replacing m by 3, :: <math>\sin{\theta_{out}} = 3 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.7293</math> :: <math>\theta_{out} = 46^\circ</math> So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== a8790f6fdeea44c0b641561f667177bd84804cb2 2729 2728 2015-10-31T21:02:31Z Jsfisher 1 /* Introduction */ wikitext text/x-wiki '''THE Holographic Geometry Equations''' by: Ed Wesly ==Introduction== At the 1982 International Symposium on Display Holography, two seminal papers on the Mathematics of Holography were presented, both by Steves, namely Benton and McGrew. This was the first time I had seen any work like this in understandable form, not like the crazed couple of pages in Principles of Holography by Howard M. Smith. These two papers, plus a follow up in the succeeding 1985 ISDH proceedings by Benton, form the basis for computation of almost all the geometrical problems facing the display holographer. With these papers, the geometry of reference and object angles for pseudo-color holograms (multi-colored replay made with a single color laser) of the transmission and reflection configurations can be plotted. (I have also used them to successfully record HOE’s for a variety of applications.) Alas and alack, these papers as written are only available in the out of print and hard to find Symposia proceedings. But the equations are available in the sites below, hopefully into perpetuity, as they are the cornerstones of the mathematical foundations of holography, although diagonally opposite. ('''Update:''' Courtesy of the author, Stephen McGrew: [http://nli-ltd.com/publications/graphical_method.php ''Graphical Methods'']) Benton’s approach is a trigonometric one, and McGrew’s is a geometric one; they are equivalent, giving the same result, except with Benton you plug and chug through equations, then map out the results. McGrew is more Euclidean; the diagram is made with straightedge and compass. Benton is the master of the realm of the transmission hologram, and his equations are set up for reference and object beam coming from the same side. You can use them to find the alpha or tip angle of the master for registered multi-color rainbow holograms, along with where the RGB slits should be placed along it. This may come as a surprise for those used to having the master hologram parallel to the copy plate when making reflection image plane holograms. But you can see from the McGrew diagrams that the light diffracted out of the H2 not only is dispersed, but the focus lies along a line that points back to the reference source! An H1 for a white light transmission hologram, either achromatic or rainbow, or a Benton hologram, (as He would prefer), is not aligned parallel to the subject! There is another school of thought, where the master position is held constant, and the reference angle for the copy plate is varied, and you could get away with an H1 parallel to the copy. But then you have to kinematically reposition these H1s during recording, instead of all three slits on one plate, a much easier approach! In either case, these equations will solve that problem, too. ==Color Shifting== The usefulness of the McGrew diagrams comes about when trying to make two different colored objects in the same image planed reflection hologram, using a chemical shifting technique with the plumping agent, TriEthanolAmine (TEA). Before attempting any of this more complicated multi-color business, the holographer should make a palette using various concentrations of TEA, as outlined in one of my contributions on this forum. http://holographyforum.org/files/tea.htm If you do this, you would find that the unswelled sample, replaying in the original laser color, will reconstruct at the original reference angle. But you will also find that the shifted colors (I am assuming that the original color is in the red region, typically He-Ne 633 red, although this will work with any red. Starting in the green means you have to post-swell to get red, another, different, kind of headache!) as they go to shorter wavelength replay are not so bright at this same angle! If you would lay your palette on the floor or table top, and position your replay light on the ceiling so that it lights up your unshrunk red most favorably, you would put the rest of them on the table above the red in ascending order of TEA concentrations, to get their brightest replay. [[Image:TEAColor.jpg]] This picture is not intended to be accurate, it is only to illustrate the trend: as the TEA concentration gets higher, with shrinkage to the bluer regions, the reference angle gets smaller. The same fringe pattern is seen by the untreated control plate and the TEA-drenched plate to be shifted. If, after processing, the TEA treated one is resoaked in the same concentration, the fringes in the two holograms would be parallel. Without the expanding additive, the emulsion collapses down to its original out of the box thickness, not only compressing the spacing between the fringes to support a shorter wavelength, but changing their tilt. This tilt is in the direction of making the angle between the reconstructing (or illuminating) beam and the reconstructed beam smaller, as in the illustration above. McGrew’s graphical reconstruction will allow the holographer to compensate for this change in replay conditions. In a nutshell, what needs to be done is to use larger reference angles during recording for the higher concentrations of TEA so that all images will replay with the same illumination angle after the shrinkage. Both Lon Moore and John Kaufman, pioneers of this technique, give their prop’s to Professor McGrew (although that term hadn’t come into usage in that pre-rapper era) in their papers in the same ISDH volume. The only thing that these papers don’t predict is the loss of brightness with the change of angle. The holographer needs to tweak things by trial and error to balance colors properly. But the quasi-thick/thin behavior of the typical 6-7 micron emulsion of the commercial silver halide products is quite forgiving for most applications. ==The Equations== Let’s go through these equations with Adjunct Assistant Professor Ed Wesly as your guide. It would be a good idea to conjure up another instance of your browser to go to these sites and jump back and forth between the two. The Benton equations are presented as part of one of his MIT courses, so let’s take a trip to Cambridge, Mass! (You may have to cut and paste these links into your second browser, as I am not so sure how successfully they will work.) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html Here are the angle conventions used in this article: [[Image:AngleConv.gif]] ==Spatial Frequency== :: <math>\displaystyle f = \frac{sin(\theta_1) - sin(\theta_2)}{\lambda}</math> Frequency, how often something happens, the frequencies most often coming to mind are the 20 to 20,000 cycles per second (abbreviated as Hertz) of good human hearing (not mine, for sure!) or the radio frequencies of 550 kiloHertz to 1800 kHZ of the AM band, or the GigaHertz processing speed of computer chips. But Hertz, (named after Heinrich Hertz, the dude who proved the existence of radio waves after James Clerk Maxwell predicted them) involve changes or cycles per second, or units of time. For holographers, we are interested in units of space, hence spatial frequency. Notice the units they are using: cycles per millimeter. Cycles because we are measuring complete phase changes, from a bright fringe to a dark fringe and back to the next bright fringe. Not individual fringes. Millimeter because it is a convenient metric unit. If it’s not familiar to you, you’d better get on the stick. What will cause some confusion in solving the upcoming equations is that because the units of spatial frequency are in cycles per mm, and our laser wavelengths are in nanometers, the latter have to be changed to the former. Milli- = thousandths, nano- = billionths, (micro- = millionths, inbetween) then there are a million nanometers in a millimeter. So the 633 nm of the He-Ne becomes .000633 mm in the equations, 515 nm Argon = .000515 mm, etc. Makes it much easier to use these decimal equivalents on the calculator than the scientific notation used in the examples. Cycles per millimeter is roughly equivalent to the line pairs per millimeter figure of merit used in evaluating photographic objectives. (The difference is that the fringe cycle is a sinusoidal variation in intensity versus the high contrast of the test target.) A very decent normal lens as made in the heyday of 35 mm film photography by Nikon or Canon could resolve 100 line pairs per millimeter on a good day. This number would be found by photographing a standard test target, usually the 1951 USAF test target, which has a variety of black and white bars of varying sizes and spacings. Google it if unfamiliar with it. Notice their sign convention: measured from the normal, with positive and negative angles. If you are not used to measuring from the normal, get with it! It is the standard of the optical industry. Not everything in optics is flat like a holo-plate; how can you measure an angle between a light ray and a convex lens or mirror surface? The normal is used, as you can generate a line that is at right angles to a circular surface at that point. Remember, there is that high school geometry saying, “a radius is at right angles to the circumference of a circle.” I used to work with a pinhead who insisted on measuring the angles from the plate surface. Even though he had been one of my grad students at one time and should have known better, he had become perverted by working for a couple of schlockmeisters who did it the lazy way, and this bozo caused us some almost catastrophic failures by not following convention! Another observation is that if you were making an unslanted grating (the fringes are at right angles to the holoplate, without a tilt) as they more or less show, with thetas 1 and 2 = 22.5 degrees, the fringe spacing would calculate differently than if you plugged in a reference theta of 45 and object theta of 0, even though there is an intra-beam angle of 45 degrees. What gives? [[Image:moire.gif]] If you would make a moiré pattern using a pair of sheets of transparency material with parallel lines ruled on them (see the above image), and set a certain angle between them (45 degrees would make the spatial frequency too high to see) and counted the fringes per inch, you would get different counts depending on how you held the ruler. If the ruler were held perpendicular to the angle bisector of the sheets (Huh? Oh, like in the MIT illustration, the unslanted fringe case!) you would get a certain count. But if you held the ruler parallel to one of the rulings, you would get a lower count over the same distance from the same fringe system! The way this equation is set up takes into account the angle of the plate with respect to the incoming waves. Related to this equation is finding the distance between fringes; instead of fringes per mm, how big is a fringe cycle? (= the distance from the center of one bright fringe to the next.) It is simply the inverse of the spatial frequency equation: :: <math>\displaystyle d = \frac{\lambda}{sin(\theta_1) - sin(\theta_2)}</math> (And don’t forget theta 2 is a negative angle, otherwise you will have an error!) (Or to make life easier, forget about the sign convention, and just add the sines of the two angles as positives together! But watch your step when getting too far off the track!) Alternatively, to find the fringe spacing distance, you could simply use the 1/x button on the calculator once you have your spatial frequency. In either case the distance will be in millimeters, and the digits will usually all pop up behind the decimal point, so if you want to convert to microns, move the decimal point over three places to the right. Onward and upward, as my Abstract Algebra teacher used to say. (while I nodded off!) http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/equations/thin-holo-eqns.pdf ==Diffraction== We just went through Interference in the section above, next on this page is Diffraction. The way that this equation is written is asking the question “what is the output angle for a given grating with a particular input angle and wavelength?” It is derived from the Interference equation by solving for the sine of one of the angles, but an extra term, m (an integer called order) pops up in this one. Let’s investigate how the two relate. Looking at the MIT diagram for calculating spatial frequency, http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html :: <math>\sin{\theta_{out}} = \sin{\theta_{in}} + m \lambda f</math> They plug in the angles, and if you are doing this at home you end up with 1805 lines per mm, which they had rounded to 1800. Substituting 40 degrees for theta in (a top lit holo in their diagram) and 1805 for f, lambda = 633 nm, same as we made it, that mysterious m set to 1 for right now, we get: (Notice that although I am considering this holo to be top referenced, this goofy MIT sign convention considers it a negative angle!) :: <math>\sin{\theta_{out}} = \sin{(-40)} + 1 (0.00033nm) (1805 c/mm)</math> :: <math>\sin{\theta_{out}} = -0.643 + 1.143</math> :: <math>\sin{\theta_{out}} = 0.500</math> :: <math>\theta_{out} = 30^\circ</math> Just like it should. If we repeat the above but with m = 2, we get: :: <math>\sin{\theta_{out}} = \sin{(-40)} + 2 (0.00033nm) (1805 c/mm)</math> :: <math>\sin{\theta_{out}} = -0.643 + 2.286</math> :: <math>\sin{\theta_{out}} = 1.643</math> Unh-unh! sin of an angle can’t be >1! (This is called a [http://en.wikipedia.org/wiki/Evanescent_wave evanescent] wave and is not propagated.) So what is the role of m? Let’s make a grating with a lower spatial frequency. (an unslanted grating with beams at a small angle to the plate) :: <math>f = \frac{\sin{10} - \sin{(-10)}}{633nm}</math> :: <math>f = 548.651...</math> (Damn, why can’t you cut and paste numbers from the Windows calculator into a document! And why does it disappear when I start typing!) Anyhow, let’s just round our spatial frequency to 550 cycles per mm. Let’s do something different when interrogating this grating this time: after processing for ultimate efficiency, let’s hit the grating with a raw, undiverged He-Ne beam along the normal, so that way sin theta in disappears (sin 0 = 0) and our output equation becomes: :: <math>\sin{\theta_{out}} = m \lambda f</math> :: <math>\sin{\theta_{out}} = 1 (.000633nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.34815</math> :: <math>\theta_{out} = 20.37^\circ</math> Replacing m by 2, :: <math>\sin{\theta_{out}} = 2 (.000633nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.6963</math> :: <math>\theta_{out} = 44.1^\circ</math> When m = 3, we get a sine > 1, so we’re out of luck. But we could also replace m by -1 and -2, getting -20.4 and -44.1 degrees as more output angles. This is the mathematics of low frequency gratings, kind of like those found in the diffraction grating goggles popular at fireworks displays etc., where you get multiple rainbows around sources of light. To see where the other end of the rainbow comes out, let’s replace lambda by another popular Helium atmosphere laser, Helium-Cadmium, at 442 nm :: <math>\sin{\theta_{out}} = 1 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.2413</math> :: <math>\theta_{out} = 14.0^\circ</math> Replacing m by 2, :: <math>\sin{\theta_{out}} = 2 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.4826</math> :: <math>\theta_{out} = 29^\circ</math> This time we can get away by replacing m by 3, :: <math>\sin{\theta_{out}} = 3 (.000442nm) (550 c/mm)</math> :: <math>\sin{\theta_{out}} = 0.7293</math> :: <math>\theta_{out} = 46^\circ</math> So if we hit this grating with the He-Cd, dead nuts on at a right angle, we would see 7 beams: the straight through zero order, (see what happens when m = 0 in the above), two beams on either side of the normal at 14, 29 and 46 degrees (corresponding to m=-3,-2,-1,0,1,2 and 3)! The red beams come out at 20 and 44 degrees. Need a picture? Either draw it yourself, or wait until I figure out how to upload! [[Image:HeCadDiffraction.gif]] Ed-click on that link to upload your file. If it is not a gif we need to edit the tag in this page. It does not matter what the original name is. If you have a diffraction grating, look at a light, and you will see, no matter what the spatial frequency, the blue or short wavelength end of the spectrum is closer to the light source than the red. The best picture of the origin of the multiple orders is to be found in The Universe of Light, by Sir William Bragg. I have a 1963 Dover reprint which is pre-ISBN number, Google or Amazon.com it yourself. Pic is on p. 131 and 133. (Now out of print.) ==Angle Equation== [[Image:AngleEq.gif]] This equation looks pretty imposing, but f in the above Diffraction Equation is replaced by the right hand side of the Interference Equation. It is used to describe the output angle of a point on an object when either the reference angle or the color of the reference beam is changed. Instead of looking at an unslanted grating, for this equation, let’s look at a single point on a traditional transmission hologram. Reference angle is 45 degree from above, (-45 in this system) and the object point is right in the center of the hologram. Preserving the recording parameters (putting the holo back in its plateholder and lighting it up under the exposure conditions): [[Image:AngleEqEx1.gif]] Which is what we started with. Moving the reference beam 5 degrees upward to 50 degrees: [[Image:AngleEqEx2.gif]] We moved the reference beam upward 5 degrees, but the object only responded with a 3+ degree upward movement. This is the nature of relationships founded on sine curves. Moving the reference beam 5 degrees downward to 40 degrees: [[Image:AngleEqEx3.gif]] We moved the reference beam downward 5 degrees, and again the object only responded with a 3+ degree movement, this time down below the centerline we had established. [[Image:EdAngleEq1.jpg]] Little m, the order number, pops up in this equation again, but it is a rare contemporary hologram that exhibits higher order images. I have an early laser transmission hologram paper in my collection that boasts about a “Single Side Band Hologram” (sorry, need to find!) But even earlier, the original Gabor style holograms had lots of extra image orders or sidebands. Some holograms in my collection are late ‘60’s/early 70’s Holex Holos. These exhibit sidebands. What happens is that when viewing these images, recorded with a shallow reference angle, there is the image that is immediately apparent in the center of the hologram, but moving off to either side of center there are higher order twin images that are visible, symmetric to the reference beam. This is analogous to the higher orders that were examined in the diffraction grating scenario above. Let’s go back to those thrilling days of yesteryear when the modulation transfer function of recording materials (the ability to render higher spatial frequencies) may have been a concern and the reference angle was smaller, like 30 degrees from the normal and see what happens when m is increased. Looking at an object point that is aligned along the normal, with a shallow ref angle: [[Image:AngleEqEx4.gif]] Which is what we started with. All is well and good. Searching for higher orders or sidebands: [[Image:AngleEqEx5.gif]] This means that if this is a top lit holo, (ref angle negative in this nomenclature) we would not only see the image along the normal as expected, but another one when we stood on tippy-toes, coming up at 30 degrees from the normal. [[Image:EdAngleEq2.jpg]] Putting -1 and -2 into the above equation gives sines of angles = or > 1, so they don’t exist. But if the reference angle is less than 30, then there could be more images! But this means that you would most likely be looking at the reference beam while enjoying the first order object beam! Let’s look at what happens when the illuminating or replay wavelength is different from the recording one. We will look at the hologram of the first example made with our He-Ne and reconstruct it with our frequency doubled YAG, 532 nm, going through the same optics. [[Image:AngleEqEx6.gif]] Meaning the green image is above the red. What the heck, let’s pretend we have a full-color set up. My favorite candidate for the blue primary is 476 nm of the Argon. [[Image:AngleEqEx7.gif]] Meaning the blue image is above the green above the red, in other words closer to the reference source, as was noted in the diffraction grating examples. [[Image:EdAngleEq3.jpg]] When viewing a laser hologram with a white light, you can see a continuous spectral spread of objects, the blue part closer to the illuminating beam. If this hologram is illuminated with a mercury vapor street lamp, you can see several images displaced from each other, reconstructed by each of the major lines of the Mercury spectrum. Many antique laser transmission hologram displays used these kinds of light with a filter instead of (at that time more costly) laser. An interesting lack of diffraction would occur when trying to illuminate H1’s for embossed rainbow holograms recorded at 458 nm with a 633 He-Ne. The geometry for this set up may be foreign for some, but it is standard operating procedure for registered color in the white light transmission mode. (The H1 plate was not parallel to the object, but tipped at the alpha or achromatic angle, and the collimated reference beam was at normal incidence to the plate!) [[Image:AngleEqEx8.gif]] theta out = taboo! So we get no image! ==Horizontal Focus (1/R)== [[Image:HorFocusEq.gif]] This is the most daunting of the equations we have seen so far; a fourth grader’s math nightmare; adding and subtracting fractions with unlike denominators. There are 4 R’s to be reckoned with; Radius of curvatures of reference wave, object point wave, illumination or replay light, and the output wave. Together with the previous Angle Equation, we can find the location of any object point when any of the recording or replaying parameters are transformed. This equation is analogous to two lens equations, the first being the Lensmaker’s Equation, which takes into account the radius of curvature of both the front and back lens surfaces, their separation (or thickness of the lens) and the index of refraction of the material of the lens. In the holographic case, the (1/R obj - 1/R ref) term sets up what is known in Bentonese as the lambda focus. (It is not represented in this set of equations, but does pop up in his 1982 ISDH paper.) [[Image:LamdaFocusEq.gif]] The other lens equation incorporated into this holographic one is the Simple Lens Equation, which predicts the image position based on the object position and the intrinsic focal length of the lens. 1/focal length -1/object distance = 1/ image distance [[Image:SimpleLensEq.gif]] Let’s run through an example with a collimated reference beam so that the 1/Rref drops out! (1/infinity = 0.) The object point will be placed 100 mm behind the holo plate, and we will start with a 633 nm He-Ne exposure. Since our reference angle will be 45 degrees, we won’t be seeing any second orders, so m will also disappear. [[Image:HorFocusEq1.gif]] Like it should. This is what happens when we put the exposed holo back in the plateholder and illuminate it with the recording wavelength, 633 in this case. Now let’s introduce the 532 nm beam into the set up like we did above: [[Image:HorFocusEq2.gif]] Let’s just call it 119 mm. So we are seeing the green image move back from the holo plate! We will couple that the results from the Angle Equation in a diagram below after doing the calculation for the blue. Introducing the 476 nm beam into the set up like we did above: [[Image:HorFocusEq3.gif]] Even further back! Combining these results with the angular displacements of the previous examples: [[Image:EdHorizontalFocus1.jpg]] Putting all three into one picture: [[Image:EdHorizontalFocus2.jpg]] A light gray is used for the reference path because the combined RGB beams would look white. Another case where this equation is useful is in locating an object point’s position when the reference distance is changed. Using the hologram recorded above, 633 nm, 45 degree reference from infinity, and moving the reference in to 10 meters, the 100 mm object distance becomes: [[Image:HorFocusEq4.gif]] If we get closer: [[Image:Horfocus4a.gif]] Even closer: [[Image:HorFocus4b.gif]] The object distance doesn’t change that dramatically when starting off with a collimated beam, but typical sandbox imagery has usually only about a meter or two for a reference beam path, let’s use a meter for ease of computation, 100 mm for object distance, and bringing the holo in to half a meter. [[Image:HorFocusEq5.gif]] A quarter meter replay reference distance: [[Image:HorFocusEq6.gif]] ==Continued in [[Holography Transmission Equations Part II]]== 99d0f35011ed7d45255b0e284d28f8941b47d2d4 0 820 2730 2617 2016-02-08T18:05:13Z Jsfisher 1 /* Basics */ wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right|Hologram by John Fisher]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more at 532 nm. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image shown here was created by a newcomer to DCG techniques, John Fisher. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == {{note | Chemical safety is always important. In DCG-based holography, the gelatin and water used are completely safe; isopropyl alcohol and dichromates are not. Alcohol is highly flammable, especially at the higher concentrations used in drying a hologram; dichromate is a strong skin irritant and a known carcinogen. Treat them both with the respect they deserve. | gotcha }} Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. They are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if the hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. A common method to seal the hologram is to epoxy a second glass plate to the back of the hologram plate, thereby protecting it from moisture. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> [[Bloom value|Bloom]] (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the sample a distance of 4 mm. The more rigid the sample the higher the [[Bloom value|bloom]]. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html [[Category:DCG]] [[Category:Beginner]] d7894c3502c1587726a2948b84be52fd26a5bd78 2731 2730 2016-02-08T18:05:58Z Jsfisher 1 /* Basics */ wikitext text/x-wiki Gelatin is the common base for photographic film and plates, including holographic materials. Polyester film or glass plates are coated with a thin layer of gelatin infused with silver halide and other chemicals that give the film its light-sensitive properties. The gelatin is the vehicle to carry the silver halide in place during film storage, exposure, and development. Otherwise, it is inert. However, when ammonium or potassium dichromate is mixed with the gelatin, the gelatin becomes weakly light-sensitive. This opens a door to another arena for the holographer, entirely different from the more traditional silver-halide process. The grossly simplified explanation is that light in the presence of dichromate molecules cause hardening of the gelatin. The hardened gelatin diffracts light differently from unhardened gelatin, so the gelatin can record a diffraction pattern necessary for a hologram. An exposed dichromated gelatin plate is "developed" by first removing the dichromate in a water rinse, then removing the water through a sequence of alcohol baths. == Basics == [[file:10mW_DCG.jpg|400px|right|Hologram by John Fisher]] Dichromated gelatin, or DCG, holograms are phenomenally bright. Unfortunately, gelatin is hygroscopic, meaning it has a tendancy to absorb water, and as the gelatin reabsorbs the water removed by the alcohol baths, the hologram will fade away. To preserve the hologram, it must be sealed from moisture, usually with some type of epoxy. Dichromated gelatin is roughly 1,000 times less sensitive to light than the typical silver halide film, and even then it is most sensitive at the short end of the light spectrum (blues and violets), moderately sensitive to greens, and virtually blind to reds without some complicated chemical treatment to improve its red sensitivity. Most DCG holograms are produced using green or blue lasers at the higher end of the power scale, 100 mW or more at 532 nm. A serviceable 100 mW green laser suitable for holography may be out of reach of the hobbyist wanting to just give DCG a try. Nonetheless, modest sized holograms can be produced with modest power lasers. The image shown here is of a hologram created by a newcomer to DCG techniques, John Fisher. A handful of 1/4"-20 socket-head screws were the subject; the glass plates, 2 x 3" large microscope slides, and the laser used was a Coherent C215M-10 operating at a lowly 10 mW. == Overview of the Process == {{note | Chemical safety is always important. In DCG-based holography, the gelatin and water used are completely safe; isopropyl alcohol and dichromates are not. Alcohol is highly flammable, especially at the higher concentrations used in drying a hologram; dichromate is a strong skin irritant and a known carcinogen. Treat them both with the respect they deserve. | gotcha }} Conceptually, making dichromated gelatin plates then processing them after exposure is fundamentally simple. The emulsion is made from ammonium or potassium dichromate, gelatin, and water. Often the formula used is expressed as a series of three numbers, where the numbers represent the ratio of the three components. The recipe, 5-30-250, means 5 grams of dichromate to 30 grams of gelatin to 250 milliliters of water (also grams). The gelatin is first added to cold water and allowed to swell, the mixture is heated while stirred continually until the gelatin is completely dissolved. The dichromate is then added with continued stirring until completely dissolved. The mixture of water, gelatin, and dichromate, still warm, is applied to glass plates. The simplest method is called veil coating in which the mixture is poured onto an angled plate and allowed to flow over it. Other methods include first pouring a line of mixture at one end of a plate then using a Meyer bar or doctor's blade to drag the mixture across the plate. Spin coating is possible, but at much lower rotational speeds then is used for, say, integrated circuit production, and tends to be very wasteful of mixture. Low-speed spinning can be used after any of the other coating methods to get a more even distribution. Coated plates are then allowed to dry. They are usually ready for exposure 4 to 12 hours later. Since dichromated gelatin can be 1,000 times less sensitive to light at 532 nm (for example) than silver halide emulsions, exposures may take a while. After exposure, the plate is left to sit in the dark for a few minutes before processing begins. Fixing is first, and this can be done either chemically with a standard photographic fixer or optically with a few seconds exposure under intense white light. Washing is next to remove the dichromate from the gelatin. Finally comes the drying step, and this involves a sequence of progressively more concentrated isopropyl alcohol baths, the last bath being 99% alcohol. Hot air drying is next to remove the alcohol. Once completely dry, the DCG hologram can be quite spectacular. The diffraction efficiency can be over 90% with no noticeable grain, and the hologram itself is very bright. Unfortunately, it will not last if the hologram is not sealed. Gelatin is hydroscopic, and therefore absorbs water. As water returns to the gelatin matrix, the hologram disappears. A common method to seal the hologram is to epoxy a second glass plate to the back of the hologram plate, thereby protecting it from moisture. == More Information == * [[A Beginner's Approach to DCG Holography]] has a more detailed and complete description of the whole process. * [[A Simple DCG Recipe]] delivers a simple, just-do-this explanation. * [[Dichromated Gelatin Chemistry]] has pointers to several DCG-related topics. ==The Mechanics of Gelatin in the Dichromated Holography Process== By John Pecora There is a lot of information available on collagen, gelatin and dichromated gelatin (DCG) holography but a paper that ties together these facets and can be understood by the amateur holographer is simply hard if not impossible to find. The scope of this paper is to finally bring together a concise understanding of what is happening in the DCG process. As it is impossible to footnote exact portions studied from other works because I intend to combine all research, I will simply put the credit due to the works I studied at the bottom of this paper and leave it up to the reader to research the individual papers for verification of the information I found. ===Collagen=== Collagen is a protein found in the skin, bones, tendons, cartilage, teeth, ligaments and connective tissue. It is the supporting structure for most body tissue. The collagen molecule is about 300 nm long and 1.5 nm in diameter. It is made up of three polypeptide strands, each of which is a left handed helix. These three left handed helices are wound together into a right handed triple helix. The strands are stabilized by hydrogen bonds. The sequence of the protein in the helical region consists of multiple repeats of the form –Gly–X–Y–, where X is often proline and Y is often a modified proline called 4-hydroxyproline. The glycine residues are located along the central axis of the triple helix, where tight packing of the protein strands can accommodate no other residue. For each –Gly–X–Y– triplet, one hydrogen bond forms between the amide hydrogen atom of glycine in one chain and the carbonyl oxygen atom of residue X in an adjacent chain. Hydrogen bonds involving the hydroxyl group of hydroxyproline may also stabilize the collagen triple helix. Unlike the more common α helix, the collagen helix has no intrachain hydrogen bonds. There is also some covalent crosslinking within the collagen molecule and crosslinking between molecules. In addition to hydroxyproline, collagen contains an additional modified amino acid residue called 5-hydroxylysine. Some hydroxylysine residues are covalently bonded to carbohydrate residues, making collagen a glycoprotein. The role of this glycosylation is not known. The more crosslinking the less soluble to water the collagen is. The smallest amino acid is Glycine and it is this amino acid that resides on the inside of the triple helix structure with its hydrogen atom facing inward. Two more common amino acids are Proline and Hydroxyproline and face outward. This gives the polypeptide chain its characteristic helical shape. <ref name="r2">http://en.wikipedia.org/wiki/Collagen</ref> <ref name="r3">http://www.britannica.com/eb/article-72553/protein</ref> <ref name="r4">http://www.lsbu.ac.uk/water/hygel.html</ref> <ref name="r5">http://www.stanford.edu/~spark7/</ref> <ref name="r19">http://sandwalk.blogspot.com/2007/02/collagen.html</ref> If collagen is hydrolyzed, the three amino chains are separated into a random glob, while still being bonded to adjacent chains with a peptide bonds and some hydrogen bonding. This is now the nature of gelatin. Because the structured arrangement has been broken down, the gelatin will have partial triple helices with loose ends bonded to other polypeptide strands and loose polypeptide strands bonded to other loose polypeptide strands forming a matrix of connected fully and partially broken down collagen molecules. It is this Random Coil that give gelatin its springy properties. <ref name="r6">http://en.wikipedia.org/wiki/Gelatin</ref> <ref name="r7">http://www.lsbu.ac.uk/water/hygel.html</ref> These two images were taken from source. <ref name="r16">http://aic.stanford.edu/sg/bpg/annual/v10/bp10-09.html</ref> [[Image:collagen1.gif]] Triple helix of collagen (crosslinked to another molecule from peptides at end of molecule) [[Image:collagen2.gif]] Collagen molecules line-up to form a fibril in "quarter staggered" array. ===Gelatin=== Gelatin is made by using the Hydrolysis process to get water to react with the Collagen. The Collagen undergoes partial hydrolysis and is broken down into the Random Coil Globs. The intermolecular and intramolecular bonds that render collagen insoluble to water has to be broken as well as the hydrogen bonds holding the triple helix together has to be broken. The amount of water bonded directly to the gelatin is about 12% - 14% after hydrolysis and after the gelatin is allowed to dry. As the newly formed gelatin cools, hydrogen bonds reform, forming the Random Coil Globs. Gelatin dehydrated to 2% water becomes insoluble in water because of the extensive crosslinking and is achieved by dehydraion. It is this water bonding to the polypeptide chains that keeps the chains from crosslinking. Crosslinking is the covalent (sharing of 1 or more electrons) bonding of the polypeptide chains. This gelatin can be reheated in water to break down the hydrogen bonds again and then redried. It is this latter part that we use to make emulsion. <ref name="r6" /> <ref name="r8">http://albumen.stanford.edu/library/c20/kozlov1983.html</ref> <ref name="r9">http://www.greatlakesgelatin.com/gelatin%20information.htm</ref> Gel Strength of gelatin is a measure of the rigidity of a gel formed from a 6.67% solution and prepared according to certain arbitrary prescribed conditions. <ref name="r13">http://www.gelatin-gmia.com/PDFs/2.1%20Gel%20Strength.pdf</ref> <ref name="r14">http://www.gelatin-gmia.com/index.htm</ref> [[Bloom value|Bloom]] (named after Mr Bloom whom invented the measuring device) is a measure of force (weight) required to depress a prescribed area of the surface of the sample a distance of 4 mm. The more rigid the sample the higher the [[Bloom value|bloom]]. <ref name="r13" /> <ref name="r14" /> This image was taken from source. <ref name="r16" /> [[Image:gelatin1.gif]] Denaturation of collagen ===CrVI=== Hexavalent chromium CrVI compounds are a group of chemical substances that contain the metallic element chromium in its positive-6 valence (hexavalent) state and can be found naturally in rocks but is most commonly produced by industrial processes. It has the ability to gain electrons from other elements (a strong oxidizer), which means it can react easily with them. <ref name="r10">http://www.cdc.gov/niosh/topics/hexchrom/</ref> <ref name="r12">http://solutions.3m.com/wps/portal/3M/en_US/OH-ESHexChrom/Hexavalent_Chromium/</ref> Research is needed using vitamin C with CrVI. <ref name="r11">http://en.wikipedia.org/wiki/Hexavalent_chromium</ref> ===DCG=== When Dichromate is added to a gelatin emulsion and then dried the compound is in a clear dissolved up state in a gelled solution. The Chromium is still in the CrVI state. On exposure to the appropriate light source (actinic radiation) the Chromium gains an electron by oxidizing some of the amino acid groups (Where from and how does it gain this electron?) and becomes CrV very quickly and easily. This CrV is bound more tightly then CrVI to the gelatin and cannot be easily washed away with just water. With continued exposure some of the CrV gains more electrons and becomes CrIII but this happens much more slowly then the creation of CrV from CrVI. After exposure the, in the light struck areas, there is a large amount of semi-strong bounded CrV and traces of CrIII causing crosslinking. If this latent hologram is allowed to sit in the dark, the CrV continues to gain electrons (from where?) and converts to CrIII causing additional crosslinking. Because the dark reaction of CrVI to CrV is also slow, more CrIII and more crosslinking in formed in the light struck areas CrV to CrIII, then in the non light struck areas, CrVI to CrV to CrIII. <ref name="r15">[http://www.researchgate.net/publication/235992174_Improving_the_remarkable_photosensitivity_of_dichromated_gelatin_for_hologram_recording_in_green_laser_light/file/60b7d5154907cd9f58.pdf Improving the remarkable photosensitivity of dichromated gelatin for hologram recording in green laser light. Jeff Blyth, Christopher R. Lowe, John F. Pecora]</ref> During the first step of processing (reducing agent: Fixer or Sodium Metabisulfite) the CrV is very quickly changed to CrIII and ultimately causes more crosslinking in the light struck areas of the gelatin. The CrVI is washed out as the reducing agent works much more slowly on CrVI to CrV to CrIII. So we have now just increased the crosslinking much more in the light struck areas then in the non light struck areas. And it is this highly crosslinked area of the gelatin that has a higher index of refraction then the uncrosslinked areas yielding us our phase hologram. <ref name="r15" /> The DCG hologram is then washed to remove all traces of the reducing agent, unbound Cr. and any loose gelatin. Remember, gelatin is soluble in water unless it is crosslinked. The water also has the effect of swelling the gelatin and thus the fringes so a hologram is still not visible until the gelatin and fringes have been shrunk back to their original size or at least shrunk to a size able to replay the visible wavelengths. The Hologram is then put into an alcohol bath. Many techniques have yielded good results in varying the temperature, duration, concentration and the number of these alcohol baths with each variable changing the final appearance of the hologram. The goal of the alcohol is to remove the water bound in the gelatin structure without allowing a collapse of the delicate fringe lattice structure. (Does alcohol bond where the water was bonded?) (How does alcohol absorb water?) Once the water has been unbound the hologram can be dried with forced or latent heat thus evaporating the alcohol and more of the now scarce water. Again, the more moisture that is taken out of the emulsion, the more crosslinking there is (even in unexposed regions) and the more insoluble the emulsion is. When taken below 2% water content the emulsion is insoluble at room temperature due to being fully crosslinked. ===Footnotes=== <references /> ===Additional References=== # Dark self-enhancement in dichromated-gelatin grating: a detailed study. Roma Grzymala and Tuula Keinonen # http://www.pslc.ws/mactest/gel.htm # http://www.polymerexpert.biz/PolymersandComposites.html [[Category:DCG]] [[Category:Beginner]] 40f5ef4436c9a59e04405fb9da1e70cf75e84af1 6 1293 2732 2016-05-01T00:53:53Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1294 2733 2016-05-01T00:53:54Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 1295 2734 2016-05-01T01:00:59Z Jsfisher 1 Created page with "This is the Blyth diffusion method for making silver halide holograms on glass plates and wine glasses. [[File:JBWGphoto1.jpg|400px]] Jeff Blyth with horse hologram in wine g..." wikitext text/x-wiki This is the Blyth diffusion method for making silver halide holograms on glass plates and wine glasses. [[File:JBWGphoto1.jpg|400px]] Jeff Blyth with horse hologram in wine glass == Introduction == This method is an advancement on my original system[i] where I first coated gelatin onto a glass surface and then diffused in silver salt to make it photosensitive. (This idea was then also found to be very useful to use on other pre-coated polymers). Now a real effort has been made here to make this method useable for the home-based amateur using only items purchased from the Internet or from local shops. The new “age of terrorism” has now blocked the availability of chemicals from the large manufacturers to the private addresses of peace-loving DIYers . The silver concentration used here is now three times higher than that used previously and this has raised the diffraction efficiency and much increased the photosensitivity. Previously it was found that pushing the silver concentration up to such a high level caused severe grain growth and grain growth has always been the bane of all silver halide holographic emulsion makers and even a century before them, for all emulsion makers for making Lippmann colour photographs. Here I have made 3 break-throughs in this new system. No.1: I discovered that I could greatly increase the concentration of silver ion without causing the dreaded severe grain growth phenomenon, provided that even the lowest levels of chloride ion residing in the pre-coated gelatin film could be first removed and that this could be simply done by first soaking the gelatin coating in a concentrated solution (soln) of potassium or sodium nitrate causing an ion exchange mechanism. No.2: I found that if I made my gelatin “emulsion” with silver chloride (AgCl) rather than the conventional silver bromide (AgBr), I was able to increase the photosensitivity by a factor of 3. The hologram still finishes up made in the conventional higher diffracting AgBr because I use a conventional bleach formula containing bromide ions. No.3: there is usually something present in shop-bought culinary gelatin which causes a degree of chemical fogging in the development step and that this could be prevented by simply adding a small quantity of copper sulphate to the gelatin soln prior to coating the film. [[File:JBWGphoto2.jpg|400px]] By pre-swelling before the exposure is made with a HeNe red laser, the holographic horse is yellow rather than red. By preswelling still more the horse image is green as in above photo == Chemicals available from the Internet == The first 2 on this list are especially important to be the purest you can get off the Internet. The rest are less critical but should be better than 90% pure if possible. Some of these chemicals will be used for making up the developer and bleaching solution later after the plates are made. The chemistry there will be dealt with in a separate section. '''Silver nitrate (AgNO3)''' This is available in 10g quantities. It needs to be as pure as possible via AMAZON or eBay. '''Potassium Nitrate''' “Food Grade” via eBay or AMAZON. “Food Grade” has worked OK. But it does have the disadvantage of containing an anti-caking agent. When a 10% solution is initially made up, this agent causes haziness instead of making a completely clear solution (soln). This haze will also stain the finished gelatin film. So one must make up the soln well in advance before use, then allow the agent to settle out and then carefully decant off the upper clear soln into another bottle. High purity sodium nitrate would be best but most offers are of lower purity than the food grade potassium salt, the offers also are confused with the completely unsuitable sodium nitrite. '''Sodium Chloride.''' Normal supermarket grade seems to be OK here. Even though it may contain small amounts of an anti-caking agent such as sodium ferrocyanide. '''Chromium Potassium Sulphate (or Sulfate)''' via AMAZON or eBay. This should be a purple powder . It is also called Chrome Alum. The green powder sold as Chromium sulfate (basic) is not suitable. Straightforward “Alum” or aluminium potassium sulphate is apparently useless as a gelatin hardener for us here. '''Acridine Orange''' via eBay (but not AMAZON). This is listed as “microbiological stain”. A bottle of 5g listed as “50%” from APC has worked well for use with a 532nm laser pointer .(Unfortunately the dye needed for red lasers I have only managed to get direct from Sigma-Aldrich or other big chemical companies , see section 19). '''Methanol''' 1 litre via AMAZON or eBay. '''Copper sulphate or sulfate.''' The blue crystals are easier to obtain than the white anhydrous compound, so my formulations are based on using the blue pentahydrate from eBay or AMAZON. === Developer chemicals. === '''Ascorbic acid (pure vitamin C powder).''' Ubiquitously available. '''Metol''' From eBay '''Sodium Carbonate anhydrous.''' From eBay, (this must not be the very impure “washing soda” crystals). '''Sodium Hydroxide''' from eBay. A quite good grade is needed, (not the one sold just for clearing drains). === Bleach Chemicals === '''Copper sulphate (sulfate)''' (already listed above) '''Acetic acid''' from eBay Potassium Bromide 200g analytical grade, available via AMAZON 3fb06c87ef17b50904b5fad3e24770c834cb256b 2740 2734 2016-05-01T01:13:05Z Jsfisher 1 /* Bleach Chemicals */ wikitext text/x-wiki This is the Blyth diffusion method for making silver halide holograms on glass plates and wine glasses. [[File:JBWGphoto1.jpg|400px]] Jeff Blyth with horse hologram in wine glass == Introduction == This method is an advancement on my original system[i] where I first coated gelatin onto a glass surface and then diffused in silver salt to make it photosensitive. (This idea was then also found to be very useful to use on other pre-coated polymers). Now a real effort has been made here to make this method useable for the home-based amateur using only items purchased from the Internet or from local shops. The new “age of terrorism” has now blocked the availability of chemicals from the large manufacturers to the private addresses of peace-loving DIYers . The silver concentration used here is now three times higher than that used previously and this has raised the diffraction efficiency and much increased the photosensitivity. Previously it was found that pushing the silver concentration up to such a high level caused severe grain growth and grain growth has always been the bane of all silver halide holographic emulsion makers and even a century before them, for all emulsion makers for making Lippmann colour photographs. Here I have made 3 break-throughs in this new system. No.1: I discovered that I could greatly increase the concentration of silver ion without causing the dreaded severe grain growth phenomenon, provided that even the lowest levels of chloride ion residing in the pre-coated gelatin film could be first removed and that this could be simply done by first soaking the gelatin coating in a concentrated solution (soln) of potassium or sodium nitrate causing an ion exchange mechanism. No.2: I found that if I made my gelatin “emulsion” with silver chloride (AgCl) rather than the conventional silver bromide (AgBr), I was able to increase the photosensitivity by a factor of 3. The hologram still finishes up made in the conventional higher diffracting AgBr because I use a conventional bleach formula containing bromide ions. No.3: there is usually something present in shop-bought culinary gelatin which causes a degree of chemical fogging in the development step and that this could be prevented by simply adding a small quantity of copper sulphate to the gelatin soln prior to coating the film. [[File:JBWGphoto2.jpg|400px]] By pre-swelling before the exposure is made with a HeNe red laser, the holographic horse is yellow rather than red. By preswelling still more the horse image is green as in above photo == Chemicals available from the Internet == The first 2 on this list are especially important to be the purest you can get off the Internet. The rest are less critical but should be better than 90% pure if possible. Some of these chemicals will be used for making up the developer and bleaching solution later after the plates are made. The chemistry there will be dealt with in a separate section. '''Silver nitrate (AgNO3)''' This is available in 10g quantities. It needs to be as pure as possible via AMAZON or eBay. '''Potassium Nitrate''' “Food Grade” via eBay or AMAZON. “Food Grade” has worked OK. But it does have the disadvantage of containing an anti-caking agent. When a 10% solution is initially made up, this agent causes haziness instead of making a completely clear solution (soln). This haze will also stain the finished gelatin film. So one must make up the soln well in advance before use, then allow the agent to settle out and then carefully decant off the upper clear soln into another bottle. High purity sodium nitrate would be best but most offers are of lower purity than the food grade potassium salt, the offers also are confused with the completely unsuitable sodium nitrite. '''Sodium Chloride.''' Normal supermarket grade seems to be OK here. Even though it may contain small amounts of an anti-caking agent such as sodium ferrocyanide. '''Chromium Potassium Sulphate (or Sulfate)''' via AMAZON or eBay. This should be a purple powder . It is also called Chrome Alum. The green powder sold as Chromium sulfate (basic) is not suitable. Straightforward “Alum” or aluminium potassium sulphate is apparently useless as a gelatin hardener for us here. '''Acridine Orange''' via eBay (but not AMAZON). This is listed as “microbiological stain”. A bottle of 5g listed as “50%” from APC has worked well for use with a 532nm laser pointer .(Unfortunately the dye needed for red lasers I have only managed to get direct from Sigma-Aldrich or other big chemical companies , see section 19). '''Methanol''' 1 litre via AMAZON or eBay. '''Copper sulphate or sulfate.''' The blue crystals are easier to obtain than the white anhydrous compound, so my formulations are based on using the blue pentahydrate from eBay or AMAZON. === Developer chemicals. === '''Ascorbic acid (pure vitamin C powder).''' Ubiquitously available. '''Metol''' From eBay '''Sodium Carbonate anhydrous.''' From eBay, (this must not be the very impure “washing soda” crystals). '''Sodium Hydroxide''' from eBay. A quite good grade is needed, (not the one sold just for clearing drains). === Bleach Chemicals === '''Copper sulphate (sulfate)''' (already listed above) '''Acetic acid''' from eBay Potassium Bromide 200g analytical grade, available via AMAZON === Anti-Printout chemicals === (“Print-out” is an old term used by photographers. It means a darkening occurs in the finished photograph (or hologram) in sunshine or bright lighting. AgCl exhibits the effect more strongly than AgBr. Here holograms made from emulsions that originally contained AgCl rather than AgBr are more liable to print-out even though they finish up being made mostly of AgBr, they still retain some AgCl. So an anti print-out step is important.) '''Sodium persulfate (or ammonium or potassium)''' from eBay. '''Sodium hydrogen sulfate (sulphate)''' from eBay '''Glass sheets.''' These are referred to here as “sheets” when buying the glass and “plates” when being turned into hologram recording material. It is convenient to use thin glass sheets of 2mm thickness for making small holograms up to say 5 x 4 inches for ease of cutting. However thicker glass is probably necessary for larger ambitious holograms because thin sheets can bow during exposure in a horizontal set-up. I find it very convenient to use those 10 cm square disposable laboratory weigh boats (from the Internet) as dishes to hold the solutions needed to process an exposed hologram. The great feature of these boats is that when they contain about 60 ml (but not more) of developer, another boat can float on top and this can effectively keep the developer active for many hours whereas in an open uncovered dish oxygen absorption will exhaust the developer in about half an hour. Also although the other dishes needed are not all affected by oxygen, they can be affected by evaporation, so such lids are used on them too. [[File:JBWPDishes.jpg|400px]] Disposable 10 cm square weigh-boats used as trays to hold developer and bleach. A second tray acts as a floating lid to delay oxidation and evaporation. To accommodate to these dishes I have been purchasing plates 2mm x 240mm x 160 mm. This is a convenient size for the gelatin coating procedure and is convenient for cutting into six 80 mm square plates that are a nice size for fingers to place in, and then take out of the dishes. Of course those fingers should be rubber-glove-covered. I also purchased 1 or more “carrier” sheets . These sheets were 4 mm x 270mm x 190mm. These thicker glass sheets allowed one to place the thinner glass on top with a 3 cm. border all round. “Subbing” the glass. Failure of gelatin film to adhere reliably to the glass surface can be a major problem. A common way to get adhesion is to use certain silane compounds which cause attraction chemically to the silica constituent of ordinary glass. However I have tried 3 different brands of “silane” off the Internet which were sold as aids to help bonding when using epoxy resins. These were not fully satisfactory as they frequently failed to do the job. I found a better answer to this problem was as follows. I leave the glass sheets for half an hour or more in 100% domestic bleach. I then rinse them in running tap water while wiping them well with a cloth. I then mark the back of the 2 mm glass sheet with a black “permanent” marker pen with say a “B”. (If there happened to be a scratch on one side of the glass then that should be the side that will be gelatin coated, as the gelatin film will later hide the scratch). I then hold the sheet at an angle of about 45degrees and place a clean collecting tray at the bottom end. I then pour a very dilute solution of gelatin and chromium potassium sulphate (detailed below) all over the front of the tilted plate. Although quite dilute, the gelatin content in the soln is sufficient to reduce the surface tension enough to allow a film to form, rather than form droplets. This plate is then left to dry leaving a very thin film of gelatin and chromium salt. Once dry, the sheet was placed with the treated side face-up into a preheated oven at 190-200C for about half an hour. The gelatin soln for this subbing was a diluted form of the gelatin soln used to make the main coating soln detailed below. So 5 ml of the soln detailed below was added to 100 ml of warm water and then 5 ml of stock chromium potassium sulfate soln. was added. This stock chromium soln was 4% soln. of chromium potassium sulfate and 4% glycerol. Stock Gelatin coating solution 1) I prepare a stock solution of shop-bought leaf gelatin of 12 g. in 100ml of cold deionized water. This is then placed in a water bath to prevent the gelatin getting over-heated. A thermometer is used in the inner gelatin bath to check that the temperature does not rise above 51 oC , while being constantly stirred for about 20 minutes or more. This is then filtered through a cotton handkerchief or nylon stocking to remove any froth from the surface About 0.5g copper sulphate CuSO4.5H2O is then added to about 3 ml deionized or distilled water, (DI) and the soln is then stirred into the gelatin soln. (There is often something in the shop bought gelatin that is inclined to cause mild chemical fogging. Also if the gelatin soln is over-heated this chemical fogging can become severe. This term “fogging “ is not related to the terms “haziness” or “scatter” mentioned later. “Chemical fogging” is a term used in photography to mean a degree of darkening (caused by fine silver metal grains) in developer not caused by light. 2) About 4ml of glycerol is then stirred in. I then pour it all into a clean bottle with a screw cap. Prior to coating I heat this stock solution up to 50 oC max. in a warmer. 3) I then take 2 glass sheets , one is 2mm x 240mm x 160 mm. (This size is convenient for cutting into six 80 mm square plates that will fit into those disposable 10 cm square weigh boats) . I use a 4mm thick glass sheet to act as a carrier sheet. The carrier sheet is 4 mm x 270mm x 190mm and the first glass sheet is placed on it, to make a margin of about 3 cm all the way round. Using PVC insulation tape, the thinner glass sheet is then taped down onto the carrier sheet with about 3mm of tape covering the perimeter of the thin sheet. I then place both this sheet combination and a clean plastic tray in the warmer together with the gelatin solution so that everything gets to 50 oC [[File:JBWPb3.jpg|400px]] A 2mm thick glass sheet is taped onto a larger 4mm thick "carrier" sheet. 4) I then take out the warmed sheets and put them in the tray on a horizontal surface . Then working quickly I pour roughly 20 ml of the gelatin soln. onto the centre of the thin glass sheet and quickly spread the gelatin puddle all over the sheet by hand so that the whole area of the sheet is wetted by the gelatin soln. I then quickly lift up one end of the sheet pair leaving the other end in in the warmed plastic tray and incline the sheet at an angle of about 45 degrees and pour the rest of the gelatin across the top end so that it all runs down smoothly as I move the bottle across the top. I then lift the sheets up off the tray so that excess gelatin drips off the bottom for no more than 15 sec. (If the initial wetting with the gelatin solution had not been carried out then the poured film would not have properly covered the sheet evenly). 5) I then quickly place the sheets on a cool flat horizontally correct surface, free from strong air currents. 6) I then pour the remaining gelatin in the tray back into the bottle, screw on the lid lightly and put the bottle back in the oven at 50oC. for about 5 minutes before screwing on the lid tightly and storing the bottle at room temperature for re-use at a later date. (So far I have had no sign of any moulds growing after leaving the gelatin soln. at room temperature for 6 months like this). 7) When the gelatin film has gelled, I then remove most of its water content by leaving the sheet in a good flow of room temperature air from a fan. 8) When the gelatin film is touch dry I run a scalpel blade around the tape border to avoid any gelatin being torn off the glass when I remove the tape before the next step. 9) With the tape peeled off, and the gelatin touch dry I then place just the coated sheet in a clean tray, and pour over its surface a chilled soln (at~5oC) of previously made 4% chromium potassium sulfate with 4% glycerol. After about a minute, I remove the sheet and shake it, the sheet is very soft and vulnerable at this point, so I very gently touch any droplets still on the gelatin face with a tissue, and also wipe off the back of the sheet. I then stand the sheet up and leave it drying in front of a fan with a good air flow. Meanwhile I pour the chromium soln in the tray back into its storage bottle and keep it in a fridge for further use. (If the chromium soln later loses its purple colour and starts to look greenish then it should not be re-used). It is then left in a cold airflow overnight. (The gelatin hardening by the chromium salt only really takes place when the gelatin film is in a relatively dry and unswollen state. An oven or warmer at 50 oC could be used instead to speed the slow process up to about an hour, but the gelatin film MUST firstly be made dry under a cold blower before being put in a warmer). If the room is below 20 oC it is best to use the warmer anyway, otherwise the slow hardening process may still be incomplete after 12 hours. 10) I then rinse the sheet front and back in running tap water and then with 3 changes of DI water. (Unlike the notorious dichromate which is (CrVI), it is OK here to let a small amount of this form of chromium (CrIII) go down the drain). 11) The sheets are then left in a bath of 0.10% sodium carbonate for about 2 minutes only and then briefly rinsed in DI. (Making the gelatin slightly alkaline contributes greatly to its ability to bind silver ions later). 12) The sheets are then left for several hours or overnight in a 10% soln. of pure sodium or potassium nitrate for the essential process of removing any chloride ions by a slow ion exchange mechanism. This time can be cut down to about an hour if the solution can be continuously mechanically agitated. The soln can be reused a number of times, depending on the amount of Cl ion it has exchanged for NO3 ion. Note that if the nitrate is from “food grade” potassium nitrate it should be a clear solution that has been decanted off from a whitish precipitate of anti-caking agent that has been allowed to settle out from an initially hazy solution. 13) The sheet is then rinsed well in DI and dried in a cold air flow so that it will be ready to allow silver nitrate to diffuse in. N.B. I have to be very careful to avoid any contamination from traces of chloride ions on the wet gelatin at this point. e.g. from tap water splashes, fingers, sneezing over it or forcefully pronouncing words with the letter “P”!!! (Otherwise tiny amounts of AgCl produced from stray Cl ions will grow into horrible big white grains in step 20 later.) 14) A concentrated stock soln. of silver nitrate (AgNO3) is prepared by making a solution of 10g of silver nitrate crystals to 50 ml of DI water in an ultra-clean bottle with lid. (This relatively expensive solution is very vulnerable to contamination. As well as any chloride or bromide traces, I am very careful not to allow any paper tissue particles to get into the stock bottle as such organic stuff can cause the soln to go brown due to colloidal silver formation, which can cause bad fogging during the development of the plates. ). 15) I then use the thick glass carrier sheet (carefully cleaned and free from halide traces) as a flat surface to coat the gelatin film with the silver nitrate solution by a puddle method . The room lighting does not need to be at a low traditional darkroom “safelight” level at this point. A low wattage tungsten filament bulb (eg. around 15W) is OK but not fluorescent “daylight” lighting. Using a clean syringe or pipette, I deposit a certain sized blob of silver nitrate soln. close to an edge of the carrier sheet. I then carefully place a cut piece of the gelatin coated sheet on top of the blob so that about a half to one cm. of the sheet protrudes over the edge of the carrier glass. The blob of silver nitrate soln then spreads evenly and easily over the gelatin film by capillary action except of course for the bit protruding over the edge of the thick carrier sheet. This overhang bit is useful for handling the sheet without touching the silver nitrate. The AgNO3 is allowed to soak in for about 2 minutes only. The size of the blob is roughly as follows; for an 8 cm square plate, my blob is made from about 0.8ml of the Ag solution. (Remembering that each 1ml blob will perhaps have cost you nearly a dollar in 2016). The puddle coating system usually works particularly well if the carrier sheet is first treated with “Rain-X” which is obtainable from suppliers of automobile sundries. This stuff makes the carrier glass water-repellent and helps to restrict the silver nitrate solution from straying beyond the thin glass sheet boundary). 16) The gelatin film then needs to have any AgNO3 soln. on the surface to be wiped off with care. A small car windshield wiper blade can be used as a squeegee and the rubber washed clean in DI after each use. Alternatively a clean doubly folded tissue folded over a ruler can be used as the wiper blade but using only one quick single wipe per tissue. (The tissue may contain low amounts of Cl- which could flow into the gelatin if more than a quick single wipe is used). 17) The plate is finally dried in a cool air flow, I check to see that there is no scatter at this point. If there is just the slightest mild scatter over the plate at this point then the plate should be discarded, (unless it was just caused by that anti-caking agent in KNO3). Because it means there was still some chloride ion contamination in there and the scatter will get much amplified in the step using a chloride and dye bath in section 20. If there is scatter in just a small part of the plate area then that probably means some chloride or bromide contamination from handling fingers that had been in tap-water, but it may be worth continuing by ignoring a small scattery area around the edge. Preparation of stock sodium chloride and dye solutions. 18) I prepare a 1 litre soln as follows. I add 41g. sodium chloride (NaCl) to a 1 litre bottle and add 334 ml of water, then after it has dissolved, I pour in 666 ml of ethanol or methanol. This makes a 2:1 alcohol : water soln. (These quantities do not have to be that precise, even a 10% error will probably be OK). 19) For the 8cm square plates, I take a 100ml of the stock NaCl soln. and add 2 ml of stock dye soln , then I use about 70 ml of this soln in one of those 10cm square dishes . The stock dye solutions are made as follows. For green lasers I prepare 0.5g of Acridine Orange (A.O.) per 100 ml of a 2:1 ratio of alcohol :water. The A.O. I got off the Internet is described as “50%” acridine orange.—It has worked well. For red lasers I use pinacyanol chloride, (its old name was “quinaldine blue” ). I prepare a stock soln of 0.3g of pinacyanol chloride in 100ml ethanol or methanol, (pinacyanol bromide or iodide can be used instead). It is most regrettable that I have not managed to buy this dye on the Internet as an ordinary citizen yet. This is the one item that I have had trouble with. A Chinese company does offer pinacyanol iodide on the Internet but the shipping costs quoted for just 1 gram are utterly ridiculous. So my dye had to be bought professionally from Sigma-Aldrich). 20) So to make my plate photosensitive I now have to work under an appropriate safelight; dim green for making red sensitive plates and dim red for making green sensitive plates. The safelight does not need to be as dim as was used for traditional photographic darkrooms where much more photosensitive material was used. One can get an idea of how much light of the wrong colour is coming out from your safelight from looking at the rainbow spectrum you get off the surface of any DVD held in the area of the room where you are working. I find that the “REMOTE CONTROLLED AUROGLOW” bulbs obtainable via AMAZON are excellent as safelights as they have instantly selectable colour and brightness . 21) I take the dried plate containing the AgNO3 and plunge it quickly into the chloride/dye bath for 45 seconds , agitating it constantly. (The time in this bath governs the grain growth. If it is too long the grain growth can get unacceptable, whereas if it is too short then a lot of silver nitrate could remain unconverted to silver chloride). After the 45 seconds I then without delay plunge the plate into a dish under cold running tap water and I leave it in for at least a couple of minutes or more. 22) Then the plate is inspected under reflected safelight. It must look scatter free or at least only show a very slight haziness . If there is bad scatter then the probable cause is a failure to remove traces of chloride ion effectively from the gelatin before the silver nitrate soln was applied. If the scatter is slight then it may be worth continuing anyway. Scatter just around some of the edges is quite likely to occur due to increased thickness and handling. The edges should not be included in the final holographic image anyway. Accidental areas of much greater thickness may also still contain unconverted silver nitrate. Such areas will turn rapidly black due to a deposit of silver metal when they meet the sensitizing bath of 2% ascorbic acid discussed in the next paragraph. They would also fog badly in the final development step of course. If one tries to eliminate any unconverted silver nitrate in accidentally thick areas around the edges by prolonging the time spent in the halide/dye bath, then an increased level of grain growth occurs in the thinner areas that are OK after just 45sec. of immersion only. The best one can do if unconverted AgNO3 is still thought to be lingering in thickly coated areas is to prolong the time in the running tap water, e.g. for 10 minutes, (the water should be as cold as possible). To maintain a final replay colour close to that of the laser wavelength, I then put the plate in a bath of 2% ascorbic acid (vitamin C) that has been taken to a pH of between 5 and 6 with sodium hydroxide. (If you have not got pH paper available then carefully weigh out 2.0 g vitamin C and dissolve it in 100 ml of DI. Then add 0.38g sodium hydroxide). Without this vitamin C treatment the light sensitivity of the plate is very low. I then wipe off the droplets with a tissue or give the plate the briefest rinse in DI. (I like to leave a trace of ascorbate in the plate as it helps to maintain its photosensitivity). 23) If I want to make bright green holograms from a red laser, then I must not use the ascorbate bath but instead I immerse the plate in a bath of 15% triethanolamine or ”TEA” for about a minute. (Treating with both ascorbate and TEA causes chemical fogging or darkening without light involvement). 24) I then carefully wipe the surface free of droplets using either a wiper-blade squeegee or doubly folded tissue over a ruler similar to that used for the earlier AgNO3 treatment, (but now I do not have to worry about any contamination from chloride ions). 25) I then leave the plate under a cold air blower for 20 minutes to acclimatize with ambient humidity. It is then best to leave the plate in a cardboard dark box until the next day when you are making larger holograms because the gelatin surface is probably not going to be stable enough for longer exposure times of more than say 4 seconds. However you will probably want to at least make some necessary exposure tests on small plate pieces before that. I find it best to do initial tests on a glass top table with the spread laser beam coming up from underneath the table or any frame able to hold a horizontal glass sheet. Initially it is best just to make a photographic exposure test. With the beam shuttered I place a piece of my recording plate on top of some masked off area , such as the piece of negative with lettering on it in the image below hat had been put in the beam before it was shuttered. The laser exposure times need to be sufficient to give a development time of about half a minute or less at 22C (see below under “Development Time” discussion). The “photographed” unmasked off area should look quite dark whereas the masked off area should be no more than slightly dark, ( if it is nearly as dark as the unmasked area than that means that I have a fog problem either caused by stray light or chemistry in the gelatin). [[File:JBWPb1.jpg|400px]] This is the rig I use for initially testing newly made hologram recording plate. A sheet of 5mm thick glass rests over a frame of a stool. Under the glass sheet I have a 4 mw red laser pointer sitting in a glass jar. The laser has been treated as per the images below. The beam is shuttered off with a piece of black card stuck to an upturned plastic beaker. On top of the glass are various objects for making exposure tests. I often start with making just a photographic image of a piece of film negative with lettering by placing the lettering in the centre of the beam and then with the beam shuttered I put a piece of plate ontop of the negative for an exposure test. To make holographic tests I place objects ontop of a piece of plate and give them time to settle before exposing. The aluminium cups are useful for putting over objects so that more laser light can be used to illuminate the sides of an object provided the laser has enough coherence length (see final section "Lasers"). This simple set-up is very good for making simple holograms in unstable environments. For a holographic test, the beam needs to be almost but not exactly perpendicular to the plate to make the traditional test with polished coins. With the beam shuttered, the coins are placed on top of the recording plate preferably on the glass side of the plate, and left for at least 10 minutes to settle. A newly made gelatin film may contract by a nanometre or two during exposure while it is thus sandwiched between the 2 glass sheets but simple coin holograms can still be obtainable because the coin to “emulsion” distance should stay the same at least for most of the emulsion attached to the plate’s glass. The important point about this test is to see how quickly the exposed hologram takes to darken in a developer such as TJ1 (see below). This glass table top system is excellent for making holograms in an unstable environment because the plate and object can “ride the storm” together. == Coating Curved glass surfaces such as wine glasses. == [[File:JBWGphoto3.jpg|400px]] Martini glass with cut-off stem to afford possibility of constrcting a hologram with an all-round view Wine-glasses have the very convenient property of being able to act as their own processing baths. It is best to do several glasses at the same time. I recommend getting 2 packs of 4 cheap plain wine glasses of about 250 ml (cc.) capacity. I first fill the glasses to the rim with either undiluted or 50% diluted domestic bleach solution. The bleach is left in each glass for about 15 minutes or longer. The bleach is then poured back into a bottle for re-use, and the glasses are rinsed well in running tap water and wiped around with a cloth before being given a rinse in DI. Each glass is then coated with the subbing layer described above under the title “Subbing the glass” but this time more conveniently, the subbing solution is poured into the glass and the glass is then tilted so that the soln wets the side of the glass up to the rim and the glass is then rotated so that the whole glass is wetted, the soln is then poured into the next warmed glass and so on. The treated glasses are then left standing in an airflow so that the very thin subbing film gets dry. The glasses are then placed in a preheated oven at 190-200C for about a half-hour. They are then allowed to cool and are given a rinse in DI. The glasses are then placed in a warmer at 50 C to dry. The bottle of stock gelatin solution should also be in the warmer and also a plastic or glass beaker with a spout. A typical wine glass holds about 250 ml. of soln. So I take 100 ml (or it can be less) of the 50 oC gelatin stock solution prepared as previously described and I pour it carefully and slowly into the warm beaker while trying to avoid creating any bubbles. The beaker is then used to carefully pour the gelatin soln into the wine glass without creating bubbles, (the spout makes this requirement easier than pouring straight from the warm stock bottle). The wineglass is then tilted and rotated so that the inside is all wetted by the soln up to the rim of the glass. The gelatin is then poured slowly from the glass back into the beaker trying to again avoid creating bubbles. The glass is then upturned and placed on a clean surface allowing the gelatin solution to flow down to the rim before gelling at room temperature. Meanwhile the beaker of gelatin soln is poured into the next glass at 50 oC and so on. The soln in the beaker should not be allowed to drop below say 40 oC or it may get too viscous to coat properly. (I do not recommend using a few seconds in a microwave oven to reheat it as I find that it can damage the gelatin and cause fogging later). Once the glass is cold and the gelatin film has gelled, then just the rim of each glass is carefully dipped into a bath of warm water to remove that thick gelatin layer around the rim. I try to not let this water level go higher than about 3 mm up from the rim. The glass is then still held in an upturned position and just the rim is wiped free of water droplets so that these droplets will not run down into the glass when it is placed upright. The upright glasses are then placed in a strong cool air current to remove the excess water in the gelatin. Once the gelatin film is unswollen (except for the partial swelling caused by the glycerol present), it is ready for the hardening solution to be poured in. The hardening soln is as described previously. Namely 4% chromium potassium sulfate soln with 4% glycerol chilled to about 5 oC. This solution is swirled around the wineglass so that it wets all the gelatin film and is then emptied into the next wineglass and so on. If the chromium soln has not run down the sides of the glass evenly when the glass is stood upright then any droplets should be gently removed by just touching with a paper tissue (do not wipe as the gelatin is very soft at this point), as only the absorbed chromium solution is wanted and droplets can cause a mark on the surface later. The wineglasses are then left upright in a cool airflow for several hours to harden. This hardening process is slow and if the room is particularly cold overnight say then it is best in the morning to warm the glass in a warmer at 50 oC for 20 minutes or more, or with a hairdryer at about 50 oC for a few minutes to finish off the hardening process. Any excess chromium salt is then removed under cold running tap water. [Unlike the notorious dichromate which is (CrVI), it is OK to let a small amount of this form of chromium (CrIII) go down the drain]. The glass is then shaken free of tap water droplets and rinsed at least three times with DI. Each glass in turn is then filled to the brim with a 0.1% solution of sodium carbonate for about 1 to 2 minutes and is then rinsed briefly in DI. Now follows the vital step of removing traces of chloride ions from the gelatin film. Each glass is filled to the brim with about a 10% solution of potassium or sodium nitrate. They are then left for several hours for the ion exchange process to occur. (Cl exchanged for NO3). The nitrate solution is then poured back into a bottle where it is probably reusable several times more. The glasses are then rinsed in DI three times and left in a warm air-flow. When dry they are ready for loading up with the silver soln. Diffusing in silver nitrate solution For your first wine-glass experiments it is best to only expose one side of the wine glass and therefore you should only put your expensive silver solution on one side of the glass. Covering the whole glass with silver causes real complications for an object such as a model figurine, because it will record a photographic shadow on the opposite side of the glass. It will also record spurious rainbow coloured effects due to transmission type gratings . However, it is worth covering the whole glass with silver solution if you want to just do a simple hologram of the glass filled to the brim with say coins. Then 2 exposures can be made 180 degrees apart and each exposure will not be affected by an exposure on the opposite side of the glass. So for making a reflexion hologram on one side of the glass only, you need to first decide which half of the coating looks the best to use and then use a marker pen to put a cross on the other side that you do not want to use. To put the silver solution into one half of the gelatin film you need a new disposable rubber glove at least on one hand. Using a 1 ml clean plastic syringe take 0.5 ml of the silver nitrate solution, and holding the glass horizontally with the future image side down, gently empty the syringe onto that concave surface. Then use your gloved forefinger to wipe the silver solution only over that designated half of the glass. Spend at least 2 minutes gently wiping that solution over just that half of the glass. At first it might seem that the solution is not wetting the film surface well and is forming droplets. However as you work at rubbing it into the gelatin, the gelatin’s surfactant properties start to kick in and the silver soln spreads more easily. This operation can be done in subdued ambient lighting such as that from a 25W or 15W tungsten filament bulb, there is no need for a proper safelight at this stage but it is vulnerable to fluorescent or blue-rich lighting. Once the gelatin layer has absorbed the silver solution, it is important to remove any excess solution off the surface or it will scar the finished hologram. I use a folded tissue to gently wipe the gelatin surface free of solution. Only use the tissue for one single quick wipe then throw it away and use another clean tissue if needed. If you plan to use the whole glass for 2 images on opposite sides then you will need to use 1.0 ml of silver nitrate soln and spend at least 3 minutes rubbing the solution over the whole surface before wiping off the excess with tissues. The glass should now look clear and scatter-free at this point, a hairdryer is now needed to dry it in a tepid airflow because it must be fairly dry for the next step, but a hot blow must not be used. Sensitizing the gelatin film. Suitable safe lighting is now needed for the next steps. The average wine-glass will take 250 ml of liquid. So it can be convenient to pour say 300 ml of the stock sodium chloride (section 18 above) into a beaker and add about 6ml of the stock dye solution (section 19). Then about 250 ml of it can be rapidly poured into the wineglass and left in for only 45 seconds and then quickly poured back into the beaker and the glass then put into running tap water with minimal delay. A beaker should be used each time for each glass rather than pouring from one glass to the next. The timing here is important because if it is too short , not all the silver nitrate in the gelatin will be able to be converted to silver chloride and if it is too long there will be quite rapid grain growth. The thickness of the gelatin layer is also a factor in determining the optimum time. To stop the reaction of the sodium chloride solution, the glass is filled rapidly with running tap water and left in the water for several minutes. It is then shaken free of tap water and given a brief rinse in de-ionized water and then filled with about 3% vitamin C solution that has been taken to a pH of between 4.5 and 5 with sodium hydroxide or with sodium carbonate (a pH of over 7 acts as a developer and will cause chemical fogging) the glass is then given a brief DI rinse and left to dry in a good cool air flow. If you wish to use a red laser to make bright yellow-green holograms then the ascorbic acid treatment should not be used and should be substituted with a soln of 12% TEA. After a minute or two in this TEA solution, the gelatin surface should be gently wiped with tissues so that no droplets or rivulets remain. The outside of the glass should be wiped too of course so that it is smear free. The photosensitive glasses should then be dried in a good air flow and left to equilibrate in a light-tight cardboard box or cupboard. They should not be used till at least a day has passed because the gelatin layer will probably be quite unstable for many hours. The Developer It is most convenient to have a 2 part developer in two one litre bottles labelled A and B. The developer can keep indefinitely in these separate bottles. They are then used by mixing equal volumes. The developer below has been christened “TJ1” developer. (In honor of the late Tung Jeong who asked me to make a suitable developer some years ago for teaching his students). Part A 6g Metol (4-methylaminophenol sulfate) 1 litre deionized water Dissolve up first then add: 40g. Ascorbic acid (vitamin "C") (Without the Metol, the developer will still work but is slower to act and the results may be less good.) Part B 100g sodium carbonate anhydrous 30g sodium hydroxide 1 litre deionized water. (This one should be labelled "very caustic" use rubber gloves and eye protection --guard against splashing it around.) Just use equal volumes of A and B. For the 8 cm square flat glass plates, use the "floating dish" method. Two close-fitting plastic dishes are arranged so that one floats on top of the other. The volume in the lower dish should be just enough (50-60 ml) to give a minimal air gap so that the uptake of oxygen is minimised and the top dish can be used as a rocker to agitate developer over a plate. In the case of wine glasses, they can be rapidly filled to the brim with developer but because the development time needed may be only a fraction of a minute, I find it best to first wet the exposed glass with DI and then rapidly pour in roughly 60 ml of developer and then twirl the glass around while looking through it at the safelight with one eye closed to judge when the amount of darkening is sufficient as described in the next paragraph. The development does not stop by emptying the developer out into a beaker and will continue on while you are inspecting the darkening. It is stopped by giving the briefest rinse under running tap water and then pouring in the bleach solution. Development Time Developer TJ1 is intended to react quickly (to keep the silver grains spheroidal rather than filamentary, and to minimize damage to the gelatin in the strongly alkaline solution). So sufficient exposure level to give a development time of only 15-30 seconds should be aimed for. To judge when the time is enough if you have not had previous experience is a little tricky because it is rather subjective. Here is my method for beginners:- Take a small sample of the holographic recording material you will be using and totally expose it to bright daylight for at least 5 minutes. Then put it in developer for a minute. Then wash it well in a bowl of tap water and dry it . Now keep that piece of plate or film as a reference for your dark room. With your eyes adapted to your darkroom safelight, shut one eye and look through that piece of reference plate at your safelight.( Holographic recording material is never completely opaque). The degree of transparency or optical density of your reference plate tells you that the darkest parts of your developing hologram must never get as dark as that reference plate as judged with one eye shut. I just go for a “half as dark” subjective estimate, while holding the developing plate up to see the safelight through it. I then plunge plate into a dish under running tap water and then into a “stop bath” of 5% acetic acid, or straight into a dish of bleach solution which also contains a lot of acetic acid and oxidant which rapidly stops the development process in the plate. Ordinary room lighting can then be switched on. It is best to first wet your plate in DI before putting it in developer because it helps to even out the development over the plate area when the development is going to be rapid. If the plate in the white dish of developer appears to go black in only about 5 seconds then that means the development should be brought to a halt within about 15 seconds (allowing for that very rapid one eye inspection of the safelight). In that case do not carry on developing for a minute just because that is a more conventional developer time. More often than not, a rapid development and rapid stop in a bleach bath give the brightest results. However, if the film only starts to darken after about 15 seconds then about a 1 minute development time is probably about right in TJ1 developer but it may still need to be longer. Ideally the laser exposure times need to be sufficient to give a development time of not more than half a minute at 22C . A room temperature below 20C will however slow the whole process down. The development is stopped by first rapidly plunging plate into a big tap water bath for a second and then into a bath of the recommended bleach soln. The developer's useful lifetime with the floating dish method can be days, depending on usage. A yellow or mild brown colour means the developer is still good. When the developer is very dark brown it should be discarded. (It is the Metol constituent that is causing the brown colour when it is oxidised and it acts as a helpful indicator of exhaustion). Bleaching solution For reflection holograms, I find the most easily obtainable bleach is made as follows:- 20g. Copper sulphate (CuSO4. 5H2O) 80g. Potassium bromide (or sodium bromide) 70 ml Acetic acid DI to 1 litre. This is known as a rehalogenating bleach. (This is not the best for transmission holograms however). The bleach does promote grain growth, so the time in the bleach should be minimized. The bleach process should not be allowed to take much longer than about a minute. If there is a very dark area (due to over-developed up silver) that has not gone after about a minute and a half , it is best to stop the bleaching reaction anyway and wash the plate under running tap water . That still dark part will clear in the final bath used next. As this bath does not contain a lot of bromide ions there is no tendency for it to encourage more grain growth. After rinsing well under tap water, a final bath to prevent “Print Out” is needed. Anti-Printout stock solution “Print-out” Is an old term used in photography . It means a darkening occurs in the finished photograph (hologram) in ambient lighting , particularly in sunshine. 40 g. Sodium persulfate (or ammonium or potassium persulfate) 40g. Sodium hydrogen sulfate DI to 1 litre. 3 minutes in this bath followed by a very brief rinse in DI gives good print-out resistance. (Always make sure that your final rinse water is free from any traces of developer ). Bleach for transmission holograms. The anti-printout solution above will also work as a bleach for transmission holograms. This type of bleach is known as a “solvent bleach” which means that all the developed-up silver goes into solution and the final hologram will be made only from the original silver halide in the dark fringes that did not develop up, leaving the light fringes as just gelatin. It is very important in this type of bleach to have the developed-up plate well washed in DI before going into the bleach bath. This is because the plate has to be free of soluble bromide salt as does the bath itself. Then after the bleaching process is complete the plate should again first be rinsed in DI water before being given a final tap water rinse. The reason for this requirement is as follows. A final hologram’s diffractive efficiency relies on the refractive index difference between its light and dark fringes i.e. its fringe contrast. In the solvent bleach system the fringe contrast is got from silver halide left in the dark fringes against just gelatin in the now emptied-out light fringes. The removed dark silver metal is now ideally all in solution as soluble silver sulfate. However if any soluble halide ions were still present in the gelatin then these will combine at once with the developed-up silver as it is being oxidized to silver sulfate and the silver will be deposited back in the light fringes as silver halide where it will spoil the fringe contrast because the light fringes will not be just emptied out gelatin. In case you are wondering where soluble halide ions in the gelatin have come from, the answer is that they are always going to be produced by the developer---as the silver bromide gets converted to dark silver metal and the bromide goes into solution as sodium bromide salt. [[File:JBWGphoto3B.jpg|400px]] The set-up for exposing the horse hologram is shown here under HeNe light. The horse is suspended half way down the wine glass by means of a screw that passes through a metal bar which lies across the rim of the glass where it is fixed with glue-gun adhesive. The screw is made invisible by wrapping it with black flock paper. Ideally one needs to use a laser with a good coherence length. What this means in simple terms for making holograms using one beam is as follows. The diverged laser beam has to pass through the recording plate and illuminate a stable object on the other side of the plate, and then the light from the object has to pass back through the plate and form standing waves with the incoming light. These are recorded as “fringes” running inside the gelatin like the pages of a book. This forms a reflection hologram also known as a Denisyuk hologram. If the laser light were made of just one single wavelength that would be perfect because the standing wave pattern would be continuous from the plate to the object regardless of how far away the object was, provided that enough light comes back from it to form recordable light and dark fringes. However lasers are rarely so perfect and the light is usually made of a very narrow spread of wavelengths. If the object is too far back then the returning light gets out of step with the incoming light and instead of the crests and troughs of the waves coinciding they clash and fail to form the standing wave pattern. (But, at a still greater distance they do come back into step again). From the earliest days of holography, the main workhorse laser was the Helium-Neon or HeNe laser. This can give a depth of over 20 cm. in a hologram using the red 632.8 nm wavelength. However in recent years compared to the cost of a HeNe laser, incredibly cheap red laser pointers have become available and I have found that in the case of the cheapest small ones (~5 mw) I can get a surprising depth of several cm. operating in the correct mode. (A wrong mode causes striped patterns in the hologram but this effect can be temporary). The much more powerful red laser pointers with powers around 50 and 100mw., I found quite useless for holography unfortunately. 9b144ef33aee4d2dfe7d0e715e059b75ff86a1c9 2744 2740 2016-05-01T01:28:31Z Jsfisher 1 /* Coating Curved glass surfaces such as wine glasses. */ wikitext text/x-wiki This is the Blyth diffusion method for making silver halide holograms on glass plates and wine glasses. [[File:JBWGphoto1.jpg|400px]] Jeff Blyth with horse hologram in wine glass == Introduction == This method is an advancement on my original system[i] where I first coated gelatin onto a glass surface and then diffused in silver salt to make it photosensitive. (This idea was then also found to be very useful to use on other pre-coated polymers). Now a real effort has been made here to make this method useable for the home-based amateur using only items purchased from the Internet or from local shops. The new “age of terrorism” has now blocked the availability of chemicals from the large manufacturers to the private addresses of peace-loving DIYers . The silver concentration used here is now three times higher than that used previously and this has raised the diffraction efficiency and much increased the photosensitivity. Previously it was found that pushing the silver concentration up to such a high level caused severe grain growth and grain growth has always been the bane of all silver halide holographic emulsion makers and even a century before them, for all emulsion makers for making Lippmann colour photographs. Here I have made 3 break-throughs in this new system. No.1: I discovered that I could greatly increase the concentration of silver ion without causing the dreaded severe grain growth phenomenon, provided that even the lowest levels of chloride ion residing in the pre-coated gelatin film could be first removed and that this could be simply done by first soaking the gelatin coating in a concentrated solution (soln) of potassium or sodium nitrate causing an ion exchange mechanism. No.2: I found that if I made my gelatin “emulsion” with silver chloride (AgCl) rather than the conventional silver bromide (AgBr), I was able to increase the photosensitivity by a factor of 3. The hologram still finishes up made in the conventional higher diffracting AgBr because I use a conventional bleach formula containing bromide ions. No.3: there is usually something present in shop-bought culinary gelatin which causes a degree of chemical fogging in the development step and that this could be prevented by simply adding a small quantity of copper sulphate to the gelatin soln prior to coating the film. [[File:JBWGphoto2.jpg|400px]] By pre-swelling before the exposure is made with a HeNe red laser, the holographic horse is yellow rather than red. By preswelling still more the horse image is green as in above photo == Chemicals available from the Internet == The first 2 on this list are especially important to be the purest you can get off the Internet. The rest are less critical but should be better than 90% pure if possible. Some of these chemicals will be used for making up the developer and bleaching solution later after the plates are made. The chemistry there will be dealt with in a separate section. '''Silver nitrate (AgNO3)''' This is available in 10g quantities. It needs to be as pure as possible via AMAZON or eBay. '''Potassium Nitrate''' “Food Grade” via eBay or AMAZON. “Food Grade” has worked OK. But it does have the disadvantage of containing an anti-caking agent. When a 10% solution is initially made up, this agent causes haziness instead of making a completely clear solution (soln). This haze will also stain the finished gelatin film. So one must make up the soln well in advance before use, then allow the agent to settle out and then carefully decant off the upper clear soln into another bottle. High purity sodium nitrate would be best but most offers are of lower purity than the food grade potassium salt, the offers also are confused with the completely unsuitable sodium nitrite. '''Sodium Chloride.''' Normal supermarket grade seems to be OK here. Even though it may contain small amounts of an anti-caking agent such as sodium ferrocyanide. '''Chromium Potassium Sulphate (or Sulfate)''' via AMAZON or eBay. This should be a purple powder . It is also called Chrome Alum. The green powder sold as Chromium sulfate (basic) is not suitable. Straightforward “Alum” or aluminium potassium sulphate is apparently useless as a gelatin hardener for us here. '''Acridine Orange''' via eBay (but not AMAZON). This is listed as “microbiological stain”. A bottle of 5g listed as “50%” from APC has worked well for use with a 532nm laser pointer .(Unfortunately the dye needed for red lasers I have only managed to get direct from Sigma-Aldrich or other big chemical companies , see section 19). '''Methanol''' 1 litre via AMAZON or eBay. '''Copper sulphate or sulfate.''' The blue crystals are easier to obtain than the white anhydrous compound, so my formulations are based on using the blue pentahydrate from eBay or AMAZON. === Developer chemicals. === '''Ascorbic acid (pure vitamin C powder).''' Ubiquitously available. '''Metol''' From eBay '''Sodium Carbonate anhydrous.''' From eBay, (this must not be the very impure “washing soda” crystals). '''Sodium Hydroxide''' from eBay. A quite good grade is needed, (not the one sold just for clearing drains). === Bleach Chemicals === '''Copper sulphate (sulfate)''' (already listed above) '''Acetic acid''' from eBay Potassium Bromide 200g analytical grade, available via AMAZON === Anti-Printout chemicals === (“Print-out” is an old term used by photographers. It means a darkening occurs in the finished photograph (or hologram) in sunshine or bright lighting. AgCl exhibits the effect more strongly than AgBr. Here holograms made from emulsions that originally contained AgCl rather than AgBr are more liable to print-out even though they finish up being made mostly of AgBr, they still retain some AgCl. So an anti print-out step is important.) '''Sodium persulfate (or ammonium or potassium)''' from eBay. '''Sodium hydrogen sulfate (sulphate)''' from eBay '''Glass sheets.''' These are referred to here as “sheets” when buying the glass and “plates” when being turned into hologram recording material. It is convenient to use thin glass sheets of 2mm thickness for making small holograms up to say 5 x 4 inches for ease of cutting. However thicker glass is probably necessary for larger ambitious holograms because thin sheets can bow during exposure in a horizontal set-up. I find it very convenient to use those 10 cm square disposable laboratory weigh boats (from the Internet) as dishes to hold the solutions needed to process an exposed hologram. The great feature of these boats is that when they contain about 60 ml (but not more) of developer, another boat can float on top and this can effectively keep the developer active for many hours whereas in an open uncovered dish oxygen absorption will exhaust the developer in about half an hour. Also although the other dishes needed are not all affected by oxygen, they can be affected by evaporation, so such lids are used on them too. [[File:JBWPDishes.jpg|400px]] Disposable 10 cm square weigh-boats used as trays to hold developer and bleach. A second tray acts as a floating lid to delay oxidation and evaporation. To accommodate to these dishes I have been purchasing plates 2mm x 240mm x 160 mm. This is a convenient size for the gelatin coating procedure and is convenient for cutting into six 80 mm square plates that are a nice size for fingers to place in, and then take out of the dishes. Of course those fingers should be rubber-glove-covered. I also purchased 1 or more “carrier” sheets . These sheets were 4 mm x 270mm x 190mm. These thicker glass sheets allowed one to place the thinner glass on top with a 3 cm. border all round. “Subbing” the glass. Failure of gelatin film to adhere reliably to the glass surface can be a major problem. A common way to get adhesion is to use certain silane compounds which cause attraction chemically to the silica constituent of ordinary glass. However I have tried 3 different brands of “silane” off the Internet which were sold as aids to help bonding when using epoxy resins. These were not fully satisfactory as they frequently failed to do the job. I found a better answer to this problem was as follows. I leave the glass sheets for half an hour or more in 100% domestic bleach. I then rinse them in running tap water while wiping them well with a cloth. I then mark the back of the 2 mm glass sheet with a black “permanent” marker pen with say a “B”. (If there happened to be a scratch on one side of the glass then that should be the side that will be gelatin coated, as the gelatin film will later hide the scratch). I then hold the sheet at an angle of about 45degrees and place a clean collecting tray at the bottom end. I then pour a very dilute solution of gelatin and chromium potassium sulphate (detailed below) all over the front of the tilted plate. Although quite dilute, the gelatin content in the soln is sufficient to reduce the surface tension enough to allow a film to form, rather than form droplets. This plate is then left to dry leaving a very thin film of gelatin and chromium salt. Once dry, the sheet was placed with the treated side face-up into a preheated oven at 190-200C for about half an hour. The gelatin soln for this subbing was a diluted form of the gelatin soln used to make the main coating soln detailed below. So 5 ml of the soln detailed below was added to 100 ml of warm water and then 5 ml of stock chromium potassium sulfate soln. was added. This stock chromium soln was 4% soln. of chromium potassium sulfate and 4% glycerol. Stock Gelatin coating solution 1) I prepare a stock solution of shop-bought leaf gelatin of 12 g. in 100ml of cold deionized water. This is then placed in a water bath to prevent the gelatin getting over-heated. A thermometer is used in the inner gelatin bath to check that the temperature does not rise above 51 oC , while being constantly stirred for about 20 minutes or more. This is then filtered through a cotton handkerchief or nylon stocking to remove any froth from the surface About 0.5g copper sulphate CuSO4.5H2O is then added to about 3 ml deionized or distilled water, (DI) and the soln is then stirred into the gelatin soln. (There is often something in the shop bought gelatin that is inclined to cause mild chemical fogging. Also if the gelatin soln is over-heated this chemical fogging can become severe. This term “fogging “ is not related to the terms “haziness” or “scatter” mentioned later. “Chemical fogging” is a term used in photography to mean a degree of darkening (caused by fine silver metal grains) in developer not caused by light. 2) About 4ml of glycerol is then stirred in. I then pour it all into a clean bottle with a screw cap. Prior to coating I heat this stock solution up to 50 oC max. in a warmer. 3) I then take 2 glass sheets , one is 2mm x 240mm x 160 mm. (This size is convenient for cutting into six 80 mm square plates that will fit into those disposable 10 cm square weigh boats) . I use a 4mm thick glass sheet to act as a carrier sheet. The carrier sheet is 4 mm x 270mm x 190mm and the first glass sheet is placed on it, to make a margin of about 3 cm all the way round. Using PVC insulation tape, the thinner glass sheet is then taped down onto the carrier sheet with about 3mm of tape covering the perimeter of the thin sheet. I then place both this sheet combination and a clean plastic tray in the warmer together with the gelatin solution so that everything gets to 50 oC [[File:JBWPb3.jpg|400px]] A 2mm thick glass sheet is taped onto a larger 4mm thick "carrier" sheet. 4) I then take out the warmed sheets and put them in the tray on a horizontal surface . Then working quickly I pour roughly 20 ml of the gelatin soln. onto the centre of the thin glass sheet and quickly spread the gelatin puddle all over the sheet by hand so that the whole area of the sheet is wetted by the gelatin soln. I then quickly lift up one end of the sheet pair leaving the other end in in the warmed plastic tray and incline the sheet at an angle of about 45 degrees and pour the rest of the gelatin across the top end so that it all runs down smoothly as I move the bottle across the top. I then lift the sheets up off the tray so that excess gelatin drips off the bottom for no more than 15 sec. (If the initial wetting with the gelatin solution had not been carried out then the poured film would not have properly covered the sheet evenly). 5) I then quickly place the sheets on a cool flat horizontally correct surface, free from strong air currents. 6) I then pour the remaining gelatin in the tray back into the bottle, screw on the lid lightly and put the bottle back in the oven at 50oC. for about 5 minutes before screwing on the lid tightly and storing the bottle at room temperature for re-use at a later date. (So far I have had no sign of any moulds growing after leaving the gelatin soln. at room temperature for 6 months like this). 7) When the gelatin film has gelled, I then remove most of its water content by leaving the sheet in a good flow of room temperature air from a fan. 8) When the gelatin film is touch dry I run a scalpel blade around the tape border to avoid any gelatin being torn off the glass when I remove the tape before the next step. 9) With the tape peeled off, and the gelatin touch dry I then place just the coated sheet in a clean tray, and pour over its surface a chilled soln (at~5oC) of previously made 4% chromium potassium sulfate with 4% glycerol. After about a minute, I remove the sheet and shake it, the sheet is very soft and vulnerable at this point, so I very gently touch any droplets still on the gelatin face with a tissue, and also wipe off the back of the sheet. I then stand the sheet up and leave it drying in front of a fan with a good air flow. Meanwhile I pour the chromium soln in the tray back into its storage bottle and keep it in a fridge for further use. (If the chromium soln later loses its purple colour and starts to look greenish then it should not be re-used). It is then left in a cold airflow overnight. (The gelatin hardening by the chromium salt only really takes place when the gelatin film is in a relatively dry and unswollen state. An oven or warmer at 50 oC could be used instead to speed the slow process up to about an hour, but the gelatin film MUST firstly be made dry under a cold blower before being put in a warmer). If the room is below 20 oC it is best to use the warmer anyway, otherwise the slow hardening process may still be incomplete after 12 hours. 10) I then rinse the sheet front and back in running tap water and then with 3 changes of DI water. (Unlike the notorious dichromate which is (CrVI), it is OK here to let a small amount of this form of chromium (CrIII) go down the drain). 11) The sheets are then left in a bath of 0.10% sodium carbonate for about 2 minutes only and then briefly rinsed in DI. (Making the gelatin slightly alkaline contributes greatly to its ability to bind silver ions later). 12) The sheets are then left for several hours or overnight in a 10% soln. of pure sodium or potassium nitrate for the essential process of removing any chloride ions by a slow ion exchange mechanism. This time can be cut down to about an hour if the solution can be continuously mechanically agitated. The soln can be reused a number of times, depending on the amount of Cl ion it has exchanged for NO3 ion. Note that if the nitrate is from “food grade” potassium nitrate it should be a clear solution that has been decanted off from a whitish precipitate of anti-caking agent that has been allowed to settle out from an initially hazy solution. 13) The sheet is then rinsed well in DI and dried in a cold air flow so that it will be ready to allow silver nitrate to diffuse in. N.B. I have to be very careful to avoid any contamination from traces of chloride ions on the wet gelatin at this point. e.g. from tap water splashes, fingers, sneezing over it or forcefully pronouncing words with the letter “P”!!! (Otherwise tiny amounts of AgCl produced from stray Cl ions will grow into horrible big white grains in step 20 later.) 14) A concentrated stock soln. of silver nitrate (AgNO3) is prepared by making a solution of 10g of silver nitrate crystals to 50 ml of DI water in an ultra-clean bottle with lid. (This relatively expensive solution is very vulnerable to contamination. As well as any chloride or bromide traces, I am very careful not to allow any paper tissue particles to get into the stock bottle as such organic stuff can cause the soln to go brown due to colloidal silver formation, which can cause bad fogging during the development of the plates. ). 15) I then use the thick glass carrier sheet (carefully cleaned and free from halide traces) as a flat surface to coat the gelatin film with the silver nitrate solution by a puddle method . The room lighting does not need to be at a low traditional darkroom “safelight” level at this point. A low wattage tungsten filament bulb (eg. around 15W) is OK but not fluorescent “daylight” lighting. Using a clean syringe or pipette, I deposit a certain sized blob of silver nitrate soln. close to an edge of the carrier sheet. I then carefully place a cut piece of the gelatin coated sheet on top of the blob so that about a half to one cm. of the sheet protrudes over the edge of the carrier glass. The blob of silver nitrate soln then spreads evenly and easily over the gelatin film by capillary action except of course for the bit protruding over the edge of the thick carrier sheet. This overhang bit is useful for handling the sheet without touching the silver nitrate. The AgNO3 is allowed to soak in for about 2 minutes only. The size of the blob is roughly as follows; for an 8 cm square plate, my blob is made from about 0.8ml of the Ag solution. (Remembering that each 1ml blob will perhaps have cost you nearly a dollar in 2016). The puddle coating system usually works particularly well if the carrier sheet is first treated with “Rain-X” which is obtainable from suppliers of automobile sundries. This stuff makes the carrier glass water-repellent and helps to restrict the silver nitrate solution from straying beyond the thin glass sheet boundary). 16) The gelatin film then needs to have any AgNO3 soln. on the surface to be wiped off with care. A small car windshield wiper blade can be used as a squeegee and the rubber washed clean in DI after each use. Alternatively a clean doubly folded tissue folded over a ruler can be used as the wiper blade but using only one quick single wipe per tissue. (The tissue may contain low amounts of Cl- which could flow into the gelatin if more than a quick single wipe is used). 17) The plate is finally dried in a cool air flow, I check to see that there is no scatter at this point. If there is just the slightest mild scatter over the plate at this point then the plate should be discarded, (unless it was just caused by that anti-caking agent in KNO3). Because it means there was still some chloride ion contamination in there and the scatter will get much amplified in the step using a chloride and dye bath in section 20. If there is scatter in just a small part of the plate area then that probably means some chloride or bromide contamination from handling fingers that had been in tap-water, but it may be worth continuing by ignoring a small scattery area around the edge. Preparation of stock sodium chloride and dye solutions. 18) I prepare a 1 litre soln as follows. I add 41g. sodium chloride (NaCl) to a 1 litre bottle and add 334 ml of water, then after it has dissolved, I pour in 666 ml of ethanol or methanol. This makes a 2:1 alcohol : water soln. (These quantities do not have to be that precise, even a 10% error will probably be OK). 19) For the 8cm square plates, I take a 100ml of the stock NaCl soln. and add 2 ml of stock dye soln , then I use about 70 ml of this soln in one of those 10cm square dishes . The stock dye solutions are made as follows. For green lasers I prepare 0.5g of Acridine Orange (A.O.) per 100 ml of a 2:1 ratio of alcohol :water. The A.O. I got off the Internet is described as “50%” acridine orange.—It has worked well. For red lasers I use pinacyanol chloride, (its old name was “quinaldine blue” ). I prepare a stock soln of 0.3g of pinacyanol chloride in 100ml ethanol or methanol, (pinacyanol bromide or iodide can be used instead). It is most regrettable that I have not managed to buy this dye on the Internet as an ordinary citizen yet. This is the one item that I have had trouble with. A Chinese company does offer pinacyanol iodide on the Internet but the shipping costs quoted for just 1 gram are utterly ridiculous. So my dye had to be bought professionally from Sigma-Aldrich). 20) So to make my plate photosensitive I now have to work under an appropriate safelight; dim green for making red sensitive plates and dim red for making green sensitive plates. The safelight does not need to be as dim as was used for traditional photographic darkrooms where much more photosensitive material was used. One can get an idea of how much light of the wrong colour is coming out from your safelight from looking at the rainbow spectrum you get off the surface of any DVD held in the area of the room where you are working. I find that the “REMOTE CONTROLLED AUROGLOW” bulbs obtainable via AMAZON are excellent as safelights as they have instantly selectable colour and brightness . 21) I take the dried plate containing the AgNO3 and plunge it quickly into the chloride/dye bath for 45 seconds , agitating it constantly. (The time in this bath governs the grain growth. If it is too long the grain growth can get unacceptable, whereas if it is too short then a lot of silver nitrate could remain unconverted to silver chloride). After the 45 seconds I then without delay plunge the plate into a dish under cold running tap water and I leave it in for at least a couple of minutes or more. 22) Then the plate is inspected under reflected safelight. It must look scatter free or at least only show a very slight haziness . If there is bad scatter then the probable cause is a failure to remove traces of chloride ion effectively from the gelatin before the silver nitrate soln was applied. If the scatter is slight then it may be worth continuing anyway. Scatter just around some of the edges is quite likely to occur due to increased thickness and handling. The edges should not be included in the final holographic image anyway. Accidental areas of much greater thickness may also still contain unconverted silver nitrate. Such areas will turn rapidly black due to a deposit of silver metal when they meet the sensitizing bath of 2% ascorbic acid discussed in the next paragraph. They would also fog badly in the final development step of course. If one tries to eliminate any unconverted silver nitrate in accidentally thick areas around the edges by prolonging the time spent in the halide/dye bath, then an increased level of grain growth occurs in the thinner areas that are OK after just 45sec. of immersion only. The best one can do if unconverted AgNO3 is still thought to be lingering in thickly coated areas is to prolong the time in the running tap water, e.g. for 10 minutes, (the water should be as cold as possible). To maintain a final replay colour close to that of the laser wavelength, I then put the plate in a bath of 2% ascorbic acid (vitamin C) that has been taken to a pH of between 5 and 6 with sodium hydroxide. (If you have not got pH paper available then carefully weigh out 2.0 g vitamin C and dissolve it in 100 ml of DI. Then add 0.38g sodium hydroxide). Without this vitamin C treatment the light sensitivity of the plate is very low. I then wipe off the droplets with a tissue or give the plate the briefest rinse in DI. (I like to leave a trace of ascorbate in the plate as it helps to maintain its photosensitivity). 23) If I want to make bright green holograms from a red laser, then I must not use the ascorbate bath but instead I immerse the plate in a bath of 15% triethanolamine or ”TEA” for about a minute. (Treating with both ascorbate and TEA causes chemical fogging or darkening without light involvement). 24) I then carefully wipe the surface free of droplets using either a wiper-blade squeegee or doubly folded tissue over a ruler similar to that used for the earlier AgNO3 treatment, (but now I do not have to worry about any contamination from chloride ions). 25) I then leave the plate under a cold air blower for 20 minutes to acclimatize with ambient humidity. It is then best to leave the plate in a cardboard dark box until the next day when you are making larger holograms because the gelatin surface is probably not going to be stable enough for longer exposure times of more than say 4 seconds. However you will probably want to at least make some necessary exposure tests on small plate pieces before that. I find it best to do initial tests on a glass top table with the spread laser beam coming up from underneath the table or any frame able to hold a horizontal glass sheet. Initially it is best just to make a photographic exposure test. With the beam shuttered I place a piece of my recording plate on top of some masked off area , such as the piece of negative with lettering on it in the image below hat had been put in the beam before it was shuttered. The laser exposure times need to be sufficient to give a development time of about half a minute or less at 22C (see below under “Development Time” discussion). The “photographed” unmasked off area should look quite dark whereas the masked off area should be no more than slightly dark, ( if it is nearly as dark as the unmasked area than that means that I have a fog problem either caused by stray light or chemistry in the gelatin). [[File:JBWPb1.jpg|400px]] This is the rig I use for initially testing newly made hologram recording plate. A sheet of 5mm thick glass rests over a frame of a stool. Under the glass sheet I have a 4 mw red laser pointer sitting in a glass jar. The laser has been treated as per the images below. The beam is shuttered off with a piece of black card stuck to an upturned plastic beaker. On top of the glass are various objects for making exposure tests. I often start with making just a photographic image of a piece of film negative with lettering by placing the lettering in the centre of the beam and then with the beam shuttered I put a piece of plate ontop of the negative for an exposure test. To make holographic tests I place objects ontop of a piece of plate and give them time to settle before exposing. The aluminium cups are useful for putting over objects so that more laser light can be used to illuminate the sides of an object provided the laser has enough coherence length (see final section "Lasers"). This simple set-up is very good for making simple holograms in unstable environments. For a holographic test, the beam needs to be almost but not exactly perpendicular to the plate to make the traditional test with polished coins. With the beam shuttered, the coins are placed on top of the recording plate preferably on the glass side of the plate, and left for at least 10 minutes to settle. A newly made gelatin film may contract by a nanometre or two during exposure while it is thus sandwiched between the 2 glass sheets but simple coin holograms can still be obtainable because the coin to “emulsion” distance should stay the same at least for most of the emulsion attached to the plate’s glass. The important point about this test is to see how quickly the exposed hologram takes to darken in a developer such as TJ1 (see below). This glass table top system is excellent for making holograms in an unstable environment because the plate and object can “ride the storm” together. == Coating Curved glass surfaces such as wine glasses. == [[File:JBWGphoto3.jpg|400px]] Martini glass with cut-off stem to afford possibility of constrcting a hologram with an all-round view Wine-glasses have the very convenient property of being able to act as their own processing baths. It is best to do several glasses at the same time. I recommend getting 2 packs of 4 cheap plain wine glasses of about 250 ml (cc.) capacity. I first fill the glasses to the rim with either undiluted or 50% diluted domestic bleach solution. The bleach is left in each glass for about 15 minutes or longer. The bleach is then poured back into a bottle for re-use, and the glasses are rinsed well in running tap water and wiped around with a cloth before being given a rinse in DI. Each glass is then coated with the subbing layer described above under the title “Subbing the glass” but this time more conveniently, the subbing solution is poured into the glass and the glass is then tilted so that the soln wets the side of the glass up to the rim and the glass is then rotated so that the whole glass is wetted, the soln is then poured into the next warmed glass and so on. The treated glasses are then left standing in an airflow so that the very thin subbing film gets dry. The glasses are then placed in a preheated oven at 190-200C for about a half-hour. They are then allowed to cool and are given a rinse in DI. The glasses are then placed in a warmer at 50 C to dry. The bottle of stock gelatin solution should also be in the warmer and also a plastic or glass beaker with a spout. A typical wine glass holds about 250 ml. of soln. So I take 100 ml (or it can be less) of the 50 oC gelatin stock solution prepared as previously described and I pour it carefully and slowly into the warm beaker while trying to avoid creating any bubbles. The beaker is then used to carefully pour the gelatin soln into the wine glass without creating bubbles, (the spout makes this requirement easier than pouring straight from the warm stock bottle). The wineglass is then tilted and rotated so that the inside is all wetted by the soln up to the rim of the glass. The gelatin is then poured slowly from the glass back into the beaker trying to again avoid creating bubbles. The glass is then upturned and placed on a clean surface allowing the gelatin solution to flow down to the rim before gelling at room temperature. Meanwhile the beaker of gelatin soln is poured into the next glass at 50 oC and so on. The soln in the beaker should not be allowed to drop below say 40 oC or it may get too viscous to coat properly. (I do not recommend using a few seconds in a microwave oven to reheat it as I find that it can damage the gelatin and cause fogging later). Once the glass is cold and the gelatin film has gelled, then just the rim of each glass is carefully dipped into a bath of warm water to remove that thick gelatin layer around the rim. I try to not let this water level go higher than about 3 mm up from the rim. The glass is then still held in an upturned position and just the rim is wiped free of water droplets so that these droplets will not run down into the glass when it is placed upright. The upright glasses are then placed in a strong cool air current to remove the excess water in the gelatin. Once the gelatin film is unswollen (except for the partial swelling caused by the glycerol present), it is ready for the hardening solution to be poured in. The hardening soln is as described previously. Namely 4% chromium potassium sulfate soln with 4% glycerol chilled to about 5 oC. This solution is swirled around the wineglass so that it wets all the gelatin film and is then emptied into the next wineglass and so on. If the chromium soln has not run down the sides of the glass evenly when the glass is stood upright then any droplets should be gently removed by just touching with a paper tissue (do not wipe as the gelatin is very soft at this point), as only the absorbed chromium solution is wanted and droplets can cause a mark on the surface later. The wineglasses are then left upright in a cool airflow for several hours to harden. This hardening process is slow and if the room is particularly cold overnight say then it is best in the morning to warm the glass in a warmer at 50 oC for 20 minutes or more, or with a hairdryer at about 50 oC for a few minutes to finish off the hardening process. Any excess chromium salt is then removed under cold running tap water. [Unlike the notorious dichromate which is (CrVI), it is OK to let a small amount of this form of chromium (CrIII) go down the drain]. The glass is then shaken free of tap water droplets and rinsed at least three times with DI. Each glass in turn is then filled to the brim with a 0.1% solution of sodium carbonate for about 1 to 2 minutes and is then rinsed briefly in DI. Now follows the vital step of removing traces of chloride ions from the gelatin film. Each glass is filled to the brim with about a 10% solution of potassium or sodium nitrate. They are then left for several hours for the ion exchange process to occur. (Cl exchanged for NO3). The nitrate solution is then poured back into a bottle where it is probably reusable several times more. The glasses are then rinsed in DI three times and left in a warm air-flow. When dry they are ready for loading up with the silver soln. === Diffusing in silver nitrate solution === For your first wine-glass experiments it is best to only expose one side of the wine glass and therefore you should only put your expensive silver solution on one side of the glass. Covering the whole glass with silver causes real complications for an object such as a model figurine, because it will record a photographic shadow on the opposite side of the glass. It will also record spurious rainbow coloured effects due to transmission type gratings. However, it is worth covering the whole glass with silver solution if you want to just do a simple hologram of the glass filled to the brim with say coins. Then 2 exposures can be made 180 degrees apart and each exposure will not be affected by an exposure on the opposite side of the glass. So for making a reflexion hologram on one side of the glass only, you need to first decide which half of the coating looks the best to use and then use a marker pen to put a cross on the other side that you do not want to use. To put the silver solution into one half of the gelatin film you need a new disposable rubber glove at least on one hand. Using a 1 ml clean plastic syringe take 0.5 ml of the silver nitrate solution, and holding the glass horizontally with the future image side down, gently empty the syringe onto that concave surface. Then use your gloved forefinger to wipe the silver solution only over that designated half of the glass. Spend at least 2 minutes gently wiping that solution over just that half of the glass. At first it might seem that the solution is not wetting the film surface well and is forming droplets. However as you work at rubbing it into the gelatin, the gelatin’s surfactant properties start to kick in and the silver soln spreads more easily. This operation can be done in subdued ambient lighting such as that from a 25W or 15W tungsten filament bulb, there is no need for a proper safelight at this stage but it is vulnerable to fluorescent or blue-rich lighting. Once the gelatin layer has absorbed the silver solution, it is important to remove any excess solution off the surface or it will scar the finished hologram. I use a folded tissue to gently wipe the gelatin surface free of solution. Only use the tissue for one single quick wipe then throw it away and use another clean tissue if needed. If you plan to use the whole glass for 2 images on opposite sides then you will need to use 1.0 ml of silver nitrate soln and spend at least 3 minutes rubbing the solution over the whole surface before wiping off the excess with tissues. The glass should now look clear and scatter-free at this point, a hairdryer is now needed to dry it in a tepid airflow because it must be fairly dry for the next step, but a hot blow must not be used. === Sensitizing the gelatin film. === '''Suitable safe lighting is now needed for the next steps.''' The average wine-glass will take 250 ml of liquid. So it can be convenient to pour say 300 ml of the stock sodium chloride (section 18 above) into a beaker and add about 6ml of the stock dye solution (section 19). Then about 250 ml of it can be '''''rapidly''''' poured into the wineglass and left in for only 45 seconds and then quickly poured back into the beaker and the glass then put into running tap water with minimal delay. A beaker should be used each time for each glass rather than pouring from one glass to the next. The timing here is important because if it is too short , not all the silver nitrate in the gelatin will be able to be converted to silver chloride and if it is too long there will be quite rapid grain growth. The thickness of the gelatin layer is also a factor in determining the optimum time. To stop the reaction of the sodium chloride solution, the glass is filled rapidly with running tap water and left in the water for several minutes. It is then shaken free of tap water and given a brief rinse in de-ionized water and then filled with about 3% vitamin C solution that has been taken to a pH of between 4.5 and 5 with sodium hydroxide or with sodium carbonate (a pH of over 7 acts as a developer and will cause chemical fogging) the glass is then given a brief DI rinse and left to dry in a good cool air flow. If you wish to use a red laser to make bright yellow-green holograms then the ascorbic acid treatment should not be used and should be substituted with a soln of 12% TEA. After a minute or two in this TEA solution, the gelatin surface should be gently wiped with tissues so that no droplets or rivulets remain. The outside of the glass should be wiped too of course so that it is smear free. The photosensitive glasses should then be dried in a good air flow and left to equilibrate in a light-tight cardboard box or cupboard. They should not be used till at least a day has passed because the gelatin layer will probably be quite unstable for many hours. ==== The Developer ==== It is most convenient to have a 2 part developer in two one litre bottles labelled A and B. The developer can keep indefinitely in these separate bottles. They are then used by mixing equal volumes. The developer below has been christened “TJ1” developer. (In honor of the late Tung Jeong who asked me to make a suitable developer some years ago for teaching his students). '''Part A''' * 6g Metol (4-methylaminophenol sulfate) * 1 litre deionized water Dissolve up first then add: * 40g. Ascorbic acid (vitamin "C") (Without the Metol, the developer will still work but is slower to act and the results may be less good.) '''Part B''' * 100g sodium carbonate anhydrous * 30g sodium hydroxide * 1 litre deionized water. (This one should be labelled "very caustic" use rubber gloves and eye protection --guard against splashing it around.) Just use equal volumes of A and B. For the 8 cm square flat glass plates, use the "floating dish" method. Two close-fitting plastic dishes are arranged so that one floats on top of the other. The volume in the lower dish should be just enough (50-60 ml) to give a minimal air gap so that the uptake of oxygen is minimised and the top dish can be used as a rocker to agitate developer over a plate. In the case of wine glasses, they can be rapidly filled to the brim with developer but because the development time needed may be only a fraction of a minute, I find it best to first wet the exposed glass with DI and then rapidly pour in roughly 60 ml of developer and then twirl the glass around while looking through it at the safelight with one eye closed to judge when the amount of darkening is sufficient as described in the next paragraph. The development does not stop by emptying the developer out into a beaker and will continue on while you are inspecting the darkening. It is stopped by giving the briefest rinse under running tap water and then pouring in the bleach solution. ==== Development Time ==== Developer TJ1 is intended to react quickly (to keep the silver grains spheroidal rather than filamentary, and to minimize damage to the gelatin in the strongly alkaline solution). So sufficient exposure level to give a development time of only 15-30 seconds should be aimed for. To judge when the time is enough if you have not had previous experience is a little tricky because it is rather subjective. Here is my method for beginners:- Take a small sample of the holographic recording material you will be using and totally expose it to bright daylight for at least 5 minutes. Then put it in developer for a minute. Then wash it well in a bowl of tap water and dry it . Now keep that piece of plate or film as a reference for your dark room. With your eyes adapted to your darkroom safelight, shut one eye and look through that piece of reference plate at your safelight.( Holographic recording material is never completely opaque). The degree of transparency or optical density of your reference plate tells you that the darkest parts of your developing hologram must never get as dark as that reference plate as judged with one eye shut. I just go for a “half as dark” subjective estimate, while holding the developing plate up to see the safelight through it. I then plunge plate into a dish under running tap water and then into a “stop bath” of 5% acetic acid, or straight into a dish of bleach solution which also contains a lot of acetic acid and oxidant which rapidly stops the development process in the plate. Ordinary room lighting can then be switched on. It is best to first wet your plate in DI before putting it in developer because it helps to even out the development over the plate area when the development is going to be rapid. If the plate in the white dish of developer appears to go black in only about 5 seconds then that means the development should be brought to a halt within about 15 seconds (allowing for that very rapid one eye inspection of the safelight). In that case do not carry on developing for a minute just because that is a more conventional developer time. More often than not, a rapid development and rapid stop in a bleach bath give the brightest results. However, if the film only starts to darken after about 15 seconds then about a 1 minute development time is probably about right in TJ1 developer but it may still need to be longer. Ideally the laser exposure times need to be sufficient to give a development time of not more than half a minute at 22C . A room temperature below 20C will however slow the whole process down. The development is stopped by first rapidly plunging plate into a big tap water bath for a second and then into a bath of the recommended bleach soln. The developer's useful lifetime with the floating dish method can be days, depending on usage. A yellow or mild brown colour means the developer is still good. When the developer is very dark brown it should be discarded. (It is the Metol constituent that is causing the brown colour when it is oxidised and it acts as a helpful indicator of exhaustion). ==== Bleaching solution ==== For reflection holograms, I find the most easily obtainable bleach is made as follows:- * 20g. Copper sulphate (CuSO4. 5H2O) * 80g. Potassium bromide (or sodium bromide) * 70 ml Acetic acid * DI to 1 litre. This is known as a rehalogenating bleach. (This is not the best for transmission holograms however). The bleach does promote grain growth, so the time in the bleach should be minimized. The bleach process should not be allowed to take much longer than about a minute. If there is a very dark area (due to over-developed up silver) that has not gone after about a minute and a half , it is best to stop the bleaching reaction anyway and wash the plate under running tap water . That still dark part will clear in the final bath used next. As this bath does not contain a lot of bromide ions there is no tendency for it to encourage more grain growth. After rinsing well under tap water, a final bath to prevent “Print Out” is needed. ==== Anti-Printout stock solution ==== “Print-out” is an old term used in photography. It means a darkening occurs in the finished photograph (hologram) in ambient lighting , particularly in sunshine. * 40 g. Sodium persulfate (or ammonium or potassium persulfate) * 40g. Sodium hydrogen sulfate * DI to 1 litre. 3 minutes in this bath followed by a very brief rinse in DI gives good print-out resistance. (Always make sure that your final rinse water is free from any traces of developer ). ==== Bleach for transmission holograms. ==== The anti-printout solution above will also work as a bleach for transmission holograms. This type of bleach is known as a “solvent bleach” which means that all the developed-up silver goes into solution and the final hologram will be made only from the original silver halide in the dark fringes that did not develop up, leaving the light fringes as just gelatin. It is very important in this type of bleach to have the developed-up plate well washed in DI before going into the bleach bath. This is because the plate has to be free of soluble bromide salt as does the bath itself. Then after the bleaching process is complete the plate should again first be rinsed in DI water before being given a final tap water rinse. The reason for this requirement is as follows. A final hologram’s diffractive efficiency relies on the refractive index difference between its light and dark fringes i.e. its fringe contrast. In the solvent bleach system the fringe contrast is got from silver halide left in the dark fringes against just gelatin in the now emptied-out light fringes. The removed dark silver metal is now ideally all in solution as soluble silver sulfate. However if any soluble halide ions were still present in the gelatin then these will combine at once with the developed-up silver as it is being oxidized to silver sulfate and the silver will be deposited back in the light fringes as silver halide where it will spoil the fringe contrast because the light fringes will not be just emptied out gelatin. In case you are wondering where soluble halide ions in the gelatin have come from, the answer is that they are always going to be produced by the developer---as the silver bromide gets converted to dark silver metal and the bromide goes into solution as sodium bromide salt. === Lasers === [[File:JBWGphoto3B.jpg|400px]] The set-up for exposing the horse hologram is shown here under HeNe light. The horse is suspended half way down the wine glass by means of a screw that passes through a metal bar which lies across the rim of the glass where it is fixed with glue-gun adhesive. The screw is made invisible by wrapping it with black flock paper. Ideally one needs to use a laser with a good coherence length. What this means in simple terms for making holograms using one beam is as follows. The diverged laser beam has to pass through the recording plate and illuminate a stable object on the other side of the plate, and then the light from the object has to pass back through the plate and form standing waves with the incoming light. These are recorded as “fringes” running inside the gelatin like the pages of a book. This forms a reflection hologram also known as a Denisyuk hologram. If the laser light were made of just one single wavelength that would be perfect because the standing wave pattern would be continuous from the plate to the object regardless of how far away the object was, provided that enough light comes back from it to form recordable light and dark fringes. However lasers are rarely so perfect and the light is usually made of a very narrow spread of wavelengths. If the object is too far back then the returning light gets out of step with the incoming light and instead of the crests and troughs of the waves coinciding they clash and fail to form the standing wave pattern. (But, at a still greater distance they do come back into step again). From the earliest days of holography, the main workhorse laser was the Helium-Neon or HeNe laser. This can give a depth of over 20 cm. in a hologram using the red 632.8 nm wavelength. However in recent years compared to the cost of a HeNe laser, incredibly cheap red laser pointers have become available and I have found that in the case of the cheapest small ones (~5 mw) I can get a surprising depth of several cm. operating in the correct mode. (A wrong mode causes striped patterns in the hologram but this effect can be temporary). The much more powerful red laser pointers with powers around 50 and 100mw., I found quite useless for holography unfortunately. [[File:JBWGhack.jpg|400px]] [[File:JBWGhack2.jpg|400px]] This shows the simple operation of hack-sawing off the lens of a small red laser pointer (~5mw) to give a very nice bar of clean light. For stability, the 3 button batteries needed to be replaced by the equivalent 4.5 volts from a large battery with the help of wired up and partially insulated croc clips. These little laser pointers operate at a much lower current than is the case for the cheap green laser pointers and therefore temperature stability is not much of a problem. With a cheap 532nm green laser pointer , I have managed to get a hologram depth of just over 3 cm once it had achieved temperature stability after a 10 minute warm-up period using the type shown below. This time after unscrewing all detachable bits and then sawing the lens off the end, I got a roughly circular spread beam, part of the other end of the barrel is also sawn off so that I could attach a variable 3 volt d.c. power supply using croc clips. It is a good idea to hold the laser in a lab clamp and stand with only bare metal on the clamps jaws (not cork or rubber) so that it will help conduct the heat away and reach an equilibrium temperature for stability. Green lasers in the photo seem to operate with a current around 0.6 amp. But if they get too hot the light output can suddenly drop very low. The original battery supplied was listed as 3.7 volts and so this value must not be exceeded and it is best to work below this voltage level. If a holographic image shows a weird stripey image, that means the laser was operating in an unfavourable mode. [[File:JBWG.jpg|400px]] Slightly changing the voltage can often make the mode O.K. but I am afraid one can be unlucky with these very cheap lasers. I am very pleased with the luck I have had so far with such cheap laser power. With the cheapest narrower pen-like green laser-pointers, operating with two AAA batteries I found I could only get a hologram depth of little more than 1 cm, but this was still enough for making gelatin holograms of coins or of slightly angled flat mirrors to make useful sensors for moisture[ii] or protease enzymes[iii]. However, for serious holographic imaging one must spend more serious money getting a laser with a guarantee that it will operate in what is known as TEM00 mode and a coherence length of over 20 cm. [i] Blyth J. et alia The Imaging Science Journal Vol 47. 87-91 (1999) [ii] Holographic Sensor for Water in Solvents Jeff Blyth · Roger B. Millington · Andrew G. Mayes · Emma R. Frears · Christopher R. Lowe Apr 1996 · Analytical Chemistry vol 68, 1089-1094 [iii] A Holographic Sensor for Proteases Roger B. Millington · Andrew G. Mayes · Jeff. Blyth · Christopher R. Lowe Dec 1995 · Analytical Chemistry vol 67 4229-4233 ee5cf3cacc62d6780dc650ffe5a698b4fe6d4e39 2745 2744 2016-05-01T02:31:23Z Jsfisher 1 /* Anti-Printout chemicals */ wikitext text/x-wiki This is the Blyth diffusion method for making silver halide holograms on glass plates and wine glasses. [[File:JBWGphoto1.jpg|400px]] Jeff Blyth with horse hologram in wine glass == Introduction == This method is an advancement on my original system[i] where I first coated gelatin onto a glass surface and then diffused in silver salt to make it photosensitive. (This idea was then also found to be very useful to use on other pre-coated polymers). Now a real effort has been made here to make this method useable for the home-based amateur using only items purchased from the Internet or from local shops. The new “age of terrorism” has now blocked the availability of chemicals from the large manufacturers to the private addresses of peace-loving DIYers . The silver concentration used here is now three times higher than that used previously and this has raised the diffraction efficiency and much increased the photosensitivity. Previously it was found that pushing the silver concentration up to such a high level caused severe grain growth and grain growth has always been the bane of all silver halide holographic emulsion makers and even a century before them, for all emulsion makers for making Lippmann colour photographs. Here I have made 3 break-throughs in this new system. No.1: I discovered that I could greatly increase the concentration of silver ion without causing the dreaded severe grain growth phenomenon, provided that even the lowest levels of chloride ion residing in the pre-coated gelatin film could be first removed and that this could be simply done by first soaking the gelatin coating in a concentrated solution (soln) of potassium or sodium nitrate causing an ion exchange mechanism. No.2: I found that if I made my gelatin “emulsion” with silver chloride (AgCl) rather than the conventional silver bromide (AgBr), I was able to increase the photosensitivity by a factor of 3. The hologram still finishes up made in the conventional higher diffracting AgBr because I use a conventional bleach formula containing bromide ions. No.3: there is usually something present in shop-bought culinary gelatin which causes a degree of chemical fogging in the development step and that this could be prevented by simply adding a small quantity of copper sulphate to the gelatin soln prior to coating the film. [[File:JBWGphoto2.jpg|400px]] By pre-swelling before the exposure is made with a HeNe red laser, the holographic horse is yellow rather than red. By preswelling still more the horse image is green as in above photo == Chemicals available from the Internet == The first 2 on this list are especially important to be the purest you can get off the Internet. The rest are less critical but should be better than 90% pure if possible. Some of these chemicals will be used for making up the developer and bleaching solution later after the plates are made. The chemistry there will be dealt with in a separate section. '''Silver nitrate (AgNO3)''' This is available in 10g quantities. It needs to be as pure as possible via AMAZON or eBay. '''Potassium Nitrate''' “Food Grade” via eBay or AMAZON. “Food Grade” has worked OK. But it does have the disadvantage of containing an anti-caking agent. When a 10% solution is initially made up, this agent causes haziness instead of making a completely clear solution (soln). This haze will also stain the finished gelatin film. So one must make up the soln well in advance before use, then allow the agent to settle out and then carefully decant off the upper clear soln into another bottle. High purity sodium nitrate would be best but most offers are of lower purity than the food grade potassium salt, the offers also are confused with the completely unsuitable sodium nitrite. '''Sodium Chloride.''' Normal supermarket grade seems to be OK here. Even though it may contain small amounts of an anti-caking agent such as sodium ferrocyanide. '''Chromium Potassium Sulphate (or Sulfate)''' via AMAZON or eBay. This should be a purple powder . It is also called Chrome Alum. The green powder sold as Chromium sulfate (basic) is not suitable. Straightforward “Alum” or aluminium potassium sulphate is apparently useless as a gelatin hardener for us here. '''Acridine Orange''' via eBay (but not AMAZON). This is listed as “microbiological stain”. A bottle of 5g listed as “50%” from APC has worked well for use with a 532nm laser pointer .(Unfortunately the dye needed for red lasers I have only managed to get direct from Sigma-Aldrich or other big chemical companies , see section 19). '''Methanol''' 1 litre via AMAZON or eBay. '''Copper sulphate or sulfate.''' The blue crystals are easier to obtain than the white anhydrous compound, so my formulations are based on using the blue pentahydrate from eBay or AMAZON. === Developer chemicals. === '''Ascorbic acid (pure vitamin C powder).''' Ubiquitously available. '''Metol''' From eBay '''Sodium Carbonate anhydrous.''' From eBay, (this must not be the very impure “washing soda” crystals). '''Sodium Hydroxide''' from eBay. A quite good grade is needed, (not the one sold just for clearing drains). === Bleach Chemicals === '''Copper sulphate (sulfate)''' (already listed above) '''Acetic acid''' from eBay Potassium Bromide 200g analytical grade, available via AMAZON === Anti-Printout chemicals === (“Print-out” is an old term used by photographers. It means a darkening occurs in the finished photograph (or hologram) in sunshine or bright lighting. AgCl exhibits the effect more strongly than AgBr. Here holograms made from emulsions that originally contained AgCl rather than AgBr are more liable to print-out even though they finish up being made mostly of AgBr, they still retain some AgCl. So an anti print-out step is important.) '''Sodium persulfate (or ammonium or potassium)''' from eBay. '''Sodium hydrogen sulfate (sulphate)''' from eBay '''Glass sheets.''' These are referred to here as “sheets” when buying the glass and “plates” when being turned into hologram recording material. It is convenient to use thin glass sheets of 2mm thickness for making small holograms up to say 5 x 4 inches for ease of cutting. However thicker glass is probably necessary for larger ambitious holograms because thin sheets can bow during exposure in a horizontal set-up. I find it very convenient to use those 10 cm square disposable laboratory weigh boats (from the Internet) as dishes to hold the solutions needed to process an exposed hologram. The great feature of these boats is that when they contain about 60 ml (but not more) of developer, another boat can float on top and this can effectively keep the developer active for many hours whereas in an open uncovered dish oxygen absorption will exhaust the developer in about half an hour. Also although the other dishes needed are not all affected by oxygen, they can be affected by evaporation, so such lids are used on them too. [[File:JBWPDishes.jpg|400px]] Disposable 10 cm square weigh-boats used as trays to hold developer and bleach. A second tray acts as a floating lid to delay oxidation and evaporation. To accommodate to these dishes I have been purchasing plates 2mm x 240mm x 160 mm. This is a convenient size for the gelatin coating procedure and is convenient for cutting into six 80 mm square plates that are a nice size for fingers to place in, and then take out of the dishes. Of course those fingers should be rubber-glove-covered. I also purchased 1 or more “carrier” sheets . These sheets were 4 mm x 270mm x 190mm. These thicker glass sheets allowed one to place the thinner glass on top with a 3 cm. border all round. “Subbing” the glass. Failure of gelatin film to adhere reliably to the glass surface can be a major problem. A common way to get adhesion is to use certain silane compounds which cause attraction chemically to the silica constituent of ordinary glass. However I have tried 3 different brands of “silane” off the Internet which were sold as aids to help bonding when using epoxy resins. These were not fully satisfactory as they frequently failed to do the job. I found a better answer to this problem was as follows. I leave the glass sheets for half an hour or more in 100% domestic bleach. I then rinse them in running tap water while wiping them well with a cloth. I then mark the back of the 2 mm glass sheet with a black “permanent” marker pen with say a “B”. (If there happened to be a scratch on one side of the glass then that should be the side that will be gelatin coated, as the gelatin film will later hide the scratch). I then hold the sheet at an angle of about 45degrees and place a clean collecting tray at the bottom end. I then pour a very dilute solution of gelatin and chromium potassium sulphate (detailed below) all over the front of the tilted plate. Although quite dilute, the gelatin content in the soln is sufficient to reduce the surface tension enough to allow a film to form, rather than form droplets. This plate is then left to dry leaving a very thin film of gelatin and chromium salt. Once dry, the sheet was placed with the treated side face-up into a preheated oven at 190-200C for about half an hour. The gelatin soln for this subbing was a diluted form of the gelatin soln used to make the main coating soln detailed below. So 5 ml of the soln detailed below was added to 100 ml of warm water and then 5 ml of stock chromium potassium sulfate soln. was added. This stock chromium soln was 4% soln. of chromium potassium sulfate and 4% glycerol. Stock Gelatin coating solution 1) I prepare a stock solution of shop-bought leaf gelatin of 12 g. in 100ml of cold deionized water. This is then placed in a water bath to prevent the gelatin getting over-heated. A thermometer is used in the inner gelatin bath to check that the temperature does not rise above 51 oC , while being constantly stirred for about 20 minutes or more. This is then filtered through a cotton handkerchief or nylon stocking to remove any froth from the surface About 0.5g copper sulphate CuSO4.5H2O is then added to about 3 ml deionized or distilled water, (DI) and the soln is then stirred into the gelatin soln. (There is often something in the shop bought gelatin that is inclined to cause mild chemical fogging. Also if the gelatin soln is over-heated this chemical fogging can become severe. This term “fogging “ is not related to the terms “haziness” or “scatter” mentioned later. “Chemical fogging” is a term used in photography to mean a degree of darkening (caused by fine silver metal grains) in developer not caused by light. 2) About 4ml of glycerol is then stirred in. I then pour it all into a clean bottle with a screw cap. Prior to coating I heat this stock solution up to 50 oC max. in a warmer. 3) I then take 2 glass sheets , one is 2mm x 240mm x 160 mm. (This size is convenient for cutting into six 80 mm square plates that will fit into those disposable 10 cm square weigh boats) . I use a 4mm thick glass sheet to act as a carrier sheet. The carrier sheet is 4 mm x 270mm x 190mm and the first glass sheet is placed on it, to make a margin of about 3 cm all the way round. Using PVC insulation tape, the thinner glass sheet is then taped down onto the carrier sheet with about 3mm of tape covering the perimeter of the thin sheet. I then place both this sheet combination and a clean plastic tray in the warmer together with the gelatin solution so that everything gets to 50 oC [[File:JBWPb3.jpg|400px]] A 2mm thick glass sheet is taped onto a larger 4mm thick "carrier" sheet. 4) I then take out the warmed sheets and put them in the tray on a horizontal surface . Then working quickly I pour roughly 20 ml of the gelatin soln. onto the centre of the thin glass sheet and quickly spread the gelatin puddle all over the sheet by hand so that the whole area of the sheet is wetted by the gelatin soln. I then quickly lift up one end of the sheet pair leaving the other end in in the warmed plastic tray and incline the sheet at an angle of about 45 degrees and pour the rest of the gelatin across the top end so that it all runs down smoothly as I move the bottle across the top. I then lift the sheets up off the tray so that excess gelatin drips off the bottom for no more than 15 sec. (If the initial wetting with the gelatin solution had not been carried out then the poured film would not have properly covered the sheet evenly). 5) I then quickly place the sheets on a cool flat horizontally correct surface, free from strong air currents. 6) I then pour the remaining gelatin in the tray back into the bottle, screw on the lid lightly and put the bottle back in the oven at 50oC. for about 5 minutes before screwing on the lid tightly and storing the bottle at room temperature for re-use at a later date. (So far I have had no sign of any moulds growing after leaving the gelatin soln. at room temperature for 6 months like this). 7) When the gelatin film has gelled, I then remove most of its water content by leaving the sheet in a good flow of room temperature air from a fan. 8) When the gelatin film is touch dry I run a scalpel blade around the tape border to avoid any gelatin being torn off the glass when I remove the tape before the next step. 9) With the tape peeled off, and the gelatin touch dry I then place just the coated sheet in a clean tray, and pour over its surface a chilled soln (at~5oC) of previously made 4% chromium potassium sulfate with 4% glycerol. After about a minute, I remove the sheet and shake it, the sheet is very soft and vulnerable at this point, so I very gently touch any droplets still on the gelatin face with a tissue, and also wipe off the back of the sheet. I then stand the sheet up and leave it drying in front of a fan with a good air flow. Meanwhile I pour the chromium soln in the tray back into its storage bottle and keep it in a fridge for further use. (If the chromium soln later loses its purple colour and starts to look greenish then it should not be re-used). It is then left in a cold airflow overnight. (The gelatin hardening by the chromium salt only really takes place when the gelatin film is in a relatively dry and unswollen state. An oven or warmer at 50 oC could be used instead to speed the slow process up to about an hour, but the gelatin film MUST firstly be made dry under a cold blower before being put in a warmer). If the room is below 20 oC it is best to use the warmer anyway, otherwise the slow hardening process may still be incomplete after 12 hours. 10) I then rinse the sheet front and back in running tap water and then with 3 changes of DI water. (Unlike the notorious dichromate which is (CrVI), it is OK here to let a small amount of this form of chromium (CrIII) go down the drain). 11) The sheets are then left in a bath of 0.10% sodium carbonate for about 2 minutes only and then briefly rinsed in DI. (Making the gelatin slightly alkaline contributes greatly to its ability to bind silver ions later). 12) The sheets are then left for several hours or overnight in a 10% soln. of pure sodium or potassium nitrate for the essential process of removing any chloride ions by a slow ion exchange mechanism. This time can be cut down to about an hour if the solution can be continuously mechanically agitated. The soln can be reused a number of times, depending on the amount of Cl ion it has exchanged for NO3 ion. Note that if the nitrate is from “food grade” potassium nitrate it should be a clear solution that has been decanted off from a whitish precipitate of anti-caking agent that has been allowed to settle out from an initially hazy solution. 13) The sheet is then rinsed well in DI and dried in a cold air flow so that it will be ready to allow silver nitrate to diffuse in. N.B. I have to be very careful to avoid any contamination from traces of chloride ions on the wet gelatin at this point. e.g. from tap water splashes, fingers, sneezing over it or forcefully pronouncing words with the letter “P”!!! (Otherwise tiny amounts of AgCl produced from stray Cl ions will grow into horrible big white grains in step 20 later.) 14) A concentrated stock soln. of silver nitrate (AgNO3) is prepared by making a solution of 10g of silver nitrate crystals to 50 ml of DI water in an ultra-clean bottle with lid. (This relatively expensive solution is very vulnerable to contamination. As well as any chloride or bromide traces, I am very careful not to allow any paper tissue particles to get into the stock bottle as such organic stuff can cause the soln to go brown due to colloidal silver formation, which can cause bad fogging during the development of the plates. ). 15) I then use the thick glass carrier sheet (carefully cleaned and free from halide traces) as a flat surface to coat the gelatin film with the silver nitrate solution by a puddle method . The room lighting does not need to be at a low traditional darkroom “safelight” level at this point. A low wattage tungsten filament bulb (eg. around 15W) is OK but not fluorescent “daylight” lighting. Using a clean syringe or pipette, I deposit a certain sized blob of silver nitrate soln. close to an edge of the carrier sheet. I then carefully place a cut piece of the gelatin coated sheet on top of the blob so that about a half to one cm. of the sheet protrudes over the edge of the carrier glass. The blob of silver nitrate soln then spreads evenly and easily over the gelatin film by capillary action except of course for the bit protruding over the edge of the thick carrier sheet. This overhang bit is useful for handling the sheet without touching the silver nitrate. The AgNO3 is allowed to soak in for about 2 minutes only. The size of the blob is roughly as follows; for an 8 cm square plate, my blob is made from about 0.8ml of the Ag solution. (Remembering that each 1ml blob will perhaps have cost you nearly a dollar in 2016). The puddle coating system usually works particularly well if the carrier sheet is first treated with “Rain-X” which is obtainable from suppliers of automobile sundries. This stuff makes the carrier glass water-repellent and helps to restrict the silver nitrate solution from straying beyond the thin glass sheet boundary). 16) The gelatin film then needs to have any AgNO3 soln. on the surface to be wiped off with care. A small car windshield wiper blade can be used as a squeegee and the rubber washed clean in DI after each use. Alternatively a clean doubly folded tissue folded over a ruler can be used as the wiper blade but using only one quick single wipe per tissue. (The tissue may contain low amounts of Cl- which could flow into the gelatin if more than a quick single wipe is used). 17) The plate is finally dried in a cool air flow, I check to see that there is no scatter at this point. If there is just the slightest mild scatter over the plate at this point then the plate should be discarded, (unless it was just caused by that anti-caking agent in KNO3). Because it means there was still some chloride ion contamination in there and the scatter will get much amplified in the step using a chloride and dye bath in section 20. If there is scatter in just a small part of the plate area then that probably means some chloride or bromide contamination from handling fingers that had been in tap-water, but it may be worth continuing by ignoring a small scattery area around the edge. Preparation of stock sodium chloride and dye solutions. 18) I prepare a 1 litre soln as follows. I add 41g. sodium chloride (NaCl) to a 1 litre bottle and add 334 ml of water, then after it has dissolved, I pour in 666 ml of ethanol or methanol. This makes a 2:1 alcohol : water soln. (These quantities do not have to be that precise, even a 10% error will probably be OK). 19) For the 8cm square plates, I take a 100ml of the stock NaCl soln. and add 2 ml of stock dye soln , then I use about 70 ml of this soln in one of those 10cm square dishes . The stock dye solutions are made as follows. For green lasers I prepare 0.5g of Acridine Orange (A.O.) per 100 ml of a 2:1 ratio of alcohol :water. The A.O. I got off the Internet is described as “50%” acridine orange.—It has worked well. For red lasers I use pinacyanol chloride, (its old name was “quinaldine blue” ). I prepare a stock soln of 0.3g of pinacyanol chloride in 100ml ethanol or methanol, (pinacyanol bromide or iodide can be used instead). It is most regrettable that I have not managed to buy this dye on the Internet as an ordinary citizen yet. This is the one item that I have had trouble with. A Chinese company does offer pinacyanol iodide on the Internet but the shipping costs quoted for just 1 gram are utterly ridiculous. So my dye had to be bought professionally from Sigma-Aldrich). 20) So to make my plate photosensitive I now have to work under an appropriate safelight; dim green for making red sensitive plates and dim red for making green sensitive plates. The safelight does not need to be as dim as was used for traditional photographic darkrooms where much more photosensitive material was used. One can get an idea of how much light of the wrong colour is coming out from your safelight from looking at the rainbow spectrum you get off the surface of any DVD held in the area of the room where you are working. I find that the “REMOTE CONTROLLED AUROGLOW” bulbs obtainable via AMAZON are excellent as safelights as they have instantly selectable colour and brightness . 21) I take the dried plate containing the AgNO3 and plunge it quickly into the chloride/dye bath for 45 seconds , agitating it constantly. (The time in this bath governs the grain growth. If it is too long the grain growth can get unacceptable, whereas if it is too short then a lot of silver nitrate could remain unconverted to silver chloride). After the 45 seconds I then without delay plunge the plate into a dish under cold running tap water and I leave it in for at least a couple of minutes or more. 22) Then the plate is inspected under reflected safelight. It must look scatter free or at least only show a very slight haziness . If there is bad scatter then the probable cause is a failure to remove traces of chloride ion effectively from the gelatin before the silver nitrate soln was applied. If the scatter is slight then it may be worth continuing anyway. Scatter just around some of the edges is quite likely to occur due to increased thickness and handling. The edges should not be included in the final holographic image anyway. Accidental areas of much greater thickness may also still contain unconverted silver nitrate. Such areas will turn rapidly black due to a deposit of silver metal when they meet the sensitizing bath of 2% ascorbic acid discussed in the next paragraph. They would also fog badly in the final development step of course. If one tries to eliminate any unconverted silver nitrate in accidentally thick areas around the edges by prolonging the time spent in the halide/dye bath, then an increased level of grain growth occurs in the thinner areas that are OK after just 45sec. of immersion only. The best one can do if unconverted AgNO3 is still thought to be lingering in thickly coated areas is to prolong the time in the running tap water, e.g. for 10 minutes, (the water should be as cold as possible). To maintain a final replay colour close to that of the laser wavelength, I then put the plate in a bath of 2% ascorbic acid (vitamin C) that has been taken to a pH of between 5 and 6 with sodium hydroxide. (If you have not got pH paper available then carefully weigh out 2.0 g vitamin C and dissolve it in 100 ml of DI. Then add 0.38g sodium hydroxide). Without this vitamin C treatment the light sensitivity of the plate is very low. I then wipe off the droplets with a tissue or give the plate the briefest rinse in DI. (I like to leave a trace of ascorbate in the plate as it helps to maintain its photosensitivity). 23) If I want to make bright green holograms from a red laser, then I must not use the ascorbate bath but instead I immerse the plate in a bath of 15% triethanolamine or ”TEA” for about a minute. (Treating with both ascorbate and TEA causes chemical fogging or darkening without light involvement). 24) I then carefully wipe the surface free of droplets using either a wiper-blade squeegee or doubly folded tissue over a ruler similar to that used for the earlier AgNO3 treatment, (but now I do not have to worry about any contamination from chloride ions). 25) I then leave the plate under a cold air blower for 20 minutes to acclimatize with ambient humidity. It is then best to leave the plate in a cardboard dark box until the next day when you are making larger holograms because the gelatin surface is probably not going to be stable enough for longer exposure times of more than say 4 seconds. However you will probably want to at least make some necessary exposure tests on small plate pieces before that. I find it best to do initial tests on a glass top table with the spread laser beam coming up from underneath the table or any frame able to hold a horizontal glass sheet. Initially it is best just to make a photographic exposure test. With the beam shuttered I place a piece of my recording plate on top of some masked off area , such as the piece of negative with lettering on it in the image below hat had been put in the beam before it was shuttered. The laser exposure times need to be sufficient to give a development time of about half a minute or less at 22C (see below under “Development Time” discussion). The “photographed” unmasked off area should look quite dark whereas the masked off area should be no more than slightly dark, ( if it is nearly as dark as the unmasked area than that means that I have a fog problem either caused by stray light or chemistry in the gelatin). [[File:JBWPb1.jpg|400px]] This is the rig I use for initially testing newly made hologram recording plate. A sheet of 5mm thick glass rests over a frame of a stool. Under the glass sheet I have a 4 mw red laser pointer sitting in a glass jar. The laser has been treated as per the images below. The beam is shuttered off with a piece of black card stuck to an upturned plastic beaker. On top of the glass are various objects for making exposure tests. I often start with making just a photographic image of a piece of film negative with lettering by placing the lettering in the centre of the beam and then with the beam shuttered I put a piece of plate ontop of the negative for an exposure test. To make holographic tests I place objects ontop of a piece of plate and give them time to settle before exposing. The aluminium cups are useful for putting over objects so that more laser light can be used to illuminate the sides of an object provided the laser has enough coherence length (see final section "Lasers"). This simple set-up is very good for making simple holograms in unstable environments. For a holographic test, the beam needs to be almost but not exactly perpendicular to the plate to make the traditional test with polished coins. With the beam shuttered, the coins are placed on top of the recording plate preferably on the glass side of the plate, and left for at least 10 minutes to settle. A newly made gelatin film may contract by a nanometre or two during exposure while it is thus sandwiched between the 2 glass sheets but simple coin holograms can still be obtainable because the coin to “emulsion” distance should stay the same at least for most of the emulsion attached to the plate’s glass. The important point about this test is to see how quickly the exposed hologram takes to darken in a developer such as TJ1 (see below). This glass table top system is excellent for making holograms in an unstable environment because the plate and object can “ride the storm” together. == Coating Curved glass surfaces such as wine glasses. == [[File:JBWGphoto3.jpg|400px]] Martini glass with cut-off stem to afford possibility of constrcting a hologram with an all-round view Wine-glasses have the very convenient property of being able to act as their own processing baths. It is best to do several glasses at the same time. I recommend getting 2 packs of 4 cheap plain wine glasses of about 250 ml (cc.) capacity. I first fill the glasses to the rim with either undiluted or 50% diluted domestic bleach solution. The bleach is left in each glass for about 15 minutes or longer. The bleach is then poured back into a bottle for re-use, and the glasses are rinsed well in running tap water and wiped around with a cloth before being given a rinse in DI. Each glass is then coated with the subbing layer described above under the title “Subbing the glass” but this time more conveniently, the subbing solution is poured into the glass and the glass is then tilted so that the soln wets the side of the glass up to the rim and the glass is then rotated so that the whole glass is wetted, the soln is then poured into the next warmed glass and so on. The treated glasses are then left standing in an airflow so that the very thin subbing film gets dry. The glasses are then placed in a preheated oven at 190-200C for about a half-hour. They are then allowed to cool and are given a rinse in DI. The glasses are then placed in a warmer at 50 C to dry. The bottle of stock gelatin solution should also be in the warmer and also a plastic or glass beaker with a spout. A typical wine glass holds about 250 ml. of soln. So I take 100 ml (or it can be less) of the 50 oC gelatin stock solution prepared as previously described and I pour it carefully and slowly into the warm beaker while trying to avoid creating any bubbles. The beaker is then used to carefully pour the gelatin soln into the wine glass without creating bubbles, (the spout makes this requirement easier than pouring straight from the warm stock bottle). The wineglass is then tilted and rotated so that the inside is all wetted by the soln up to the rim of the glass. The gelatin is then poured slowly from the glass back into the beaker trying to again avoid creating bubbles. The glass is then upturned and placed on a clean surface allowing the gelatin solution to flow down to the rim before gelling at room temperature. Meanwhile the beaker of gelatin soln is poured into the next glass at 50 oC and so on. The soln in the beaker should not be allowed to drop below say 40 oC or it may get too viscous to coat properly. (I do not recommend using a few seconds in a microwave oven to reheat it as I find that it can damage the gelatin and cause fogging later). Once the glass is cold and the gelatin film has gelled, then just the rim of each glass is carefully dipped into a bath of warm water to remove that thick gelatin layer around the rim. I try to not let this water level go higher than about 3 mm up from the rim. The glass is then still held in an upturned position and just the rim is wiped free of water droplets so that these droplets will not run down into the glass when it is placed upright. The upright glasses are then placed in a strong cool air current to remove the excess water in the gelatin. Once the gelatin film is unswollen (except for the partial swelling caused by the glycerol present), it is ready for the hardening solution to be poured in. The hardening soln is as described previously. Namely 4% chromium potassium sulfate soln with 4% glycerol chilled to about 5 oC. This solution is swirled around the wineglass so that it wets all the gelatin film and is then emptied into the next wineglass and so on. If the chromium soln has not run down the sides of the glass evenly when the glass is stood upright then any droplets should be gently removed by just touching with a paper tissue (do not wipe as the gelatin is very soft at this point), as only the absorbed chromium solution is wanted and droplets can cause a mark on the surface later. The wineglasses are then left upright in a cool airflow for several hours to harden. This hardening process is slow and if the room is particularly cold overnight say then it is best in the morning to warm the glass in a warmer at 50 oC for 20 minutes or more, or with a hairdryer at about 50 oC for a few minutes to finish off the hardening process. Any excess chromium salt is then removed under cold running tap water. [Unlike the notorious dichromate which is (CrVI), it is OK to let a small amount of this form of chromium (CrIII) go down the drain]. The glass is then shaken free of tap water droplets and rinsed at least three times with DI. Each glass in turn is then filled to the brim with a 0.1% solution of sodium carbonate for about 1 to 2 minutes and is then rinsed briefly in DI. Now follows the vital step of removing traces of chloride ions from the gelatin film. Each glass is filled to the brim with about a 10% solution of potassium or sodium nitrate. They are then left for several hours for the ion exchange process to occur. (Cl exchanged for NO3). The nitrate solution is then poured back into a bottle where it is probably reusable several times more. The glasses are then rinsed in DI three times and left in a warm air-flow. When dry they are ready for loading up with the silver soln. === Diffusing in silver nitrate solution === For your first wine-glass experiments it is best to only expose one side of the wine glass and therefore you should only put your expensive silver solution on one side of the glass. Covering the whole glass with silver causes real complications for an object such as a model figurine, because it will record a photographic shadow on the opposite side of the glass. It will also record spurious rainbow coloured effects due to transmission type gratings. However, it is worth covering the whole glass with silver solution if you want to just do a simple hologram of the glass filled to the brim with say coins. Then 2 exposures can be made 180 degrees apart and each exposure will not be affected by an exposure on the opposite side of the glass. So for making a reflexion hologram on one side of the glass only, you need to first decide which half of the coating looks the best to use and then use a marker pen to put a cross on the other side that you do not want to use. To put the silver solution into one half of the gelatin film you need a new disposable rubber glove at least on one hand. Using a 1 ml clean plastic syringe take 0.5 ml of the silver nitrate solution, and holding the glass horizontally with the future image side down, gently empty the syringe onto that concave surface. Then use your gloved forefinger to wipe the silver solution only over that designated half of the glass. Spend at least 2 minutes gently wiping that solution over just that half of the glass. At first it might seem that the solution is not wetting the film surface well and is forming droplets. However as you work at rubbing it into the gelatin, the gelatin’s surfactant properties start to kick in and the silver soln spreads more easily. This operation can be done in subdued ambient lighting such as that from a 25W or 15W tungsten filament bulb, there is no need for a proper safelight at this stage but it is vulnerable to fluorescent or blue-rich lighting. Once the gelatin layer has absorbed the silver solution, it is important to remove any excess solution off the surface or it will scar the finished hologram. I use a folded tissue to gently wipe the gelatin surface free of solution. Only use the tissue for one single quick wipe then throw it away and use another clean tissue if needed. If you plan to use the whole glass for 2 images on opposite sides then you will need to use 1.0 ml of silver nitrate soln and spend at least 3 minutes rubbing the solution over the whole surface before wiping off the excess with tissues. The glass should now look clear and scatter-free at this point, a hairdryer is now needed to dry it in a tepid airflow because it must be fairly dry for the next step, but a hot blow must not be used. === Sensitizing the gelatin film. === '''Suitable safe lighting is now needed for the next steps.''' The average wine-glass will take 250 ml of liquid. So it can be convenient to pour say 300 ml of the stock sodium chloride (section 18 above) into a beaker and add about 6ml of the stock dye solution (section 19). Then about 250 ml of it can be '''''rapidly''''' poured into the wineglass and left in for only 45 seconds and then quickly poured back into the beaker and the glass then put into running tap water with minimal delay. A beaker should be used each time for each glass rather than pouring from one glass to the next. The timing here is important because if it is too short , not all the silver nitrate in the gelatin will be able to be converted to silver chloride and if it is too long there will be quite rapid grain growth. The thickness of the gelatin layer is also a factor in determining the optimum time. To stop the reaction of the sodium chloride solution, the glass is filled rapidly with running tap water and left in the water for several minutes. It is then shaken free of tap water and given a brief rinse in de-ionized water and then filled with about 3% vitamin C solution that has been taken to a pH of between 4.5 and 5 with sodium hydroxide or with sodium carbonate (a pH of over 7 acts as a developer and will cause chemical fogging) the glass is then given a brief DI rinse and left to dry in a good cool air flow. If you wish to use a red laser to make bright yellow-green holograms then the ascorbic acid treatment should not be used and should be substituted with a soln of 12% TEA. After a minute or two in this TEA solution, the gelatin surface should be gently wiped with tissues so that no droplets or rivulets remain. The outside of the glass should be wiped too of course so that it is smear free. The photosensitive glasses should then be dried in a good air flow and left to equilibrate in a light-tight cardboard box or cupboard. They should not be used till at least a day has passed because the gelatin layer will probably be quite unstable for many hours. ==== The Developer ==== It is most convenient to have a 2 part developer in two one litre bottles labelled A and B. The developer can keep indefinitely in these separate bottles. They are then used by mixing equal volumes. The developer below has been christened “TJ1” developer. (In honor of the late Tung Jeong who asked me to make a suitable developer some years ago for teaching his students). '''Part A''' * 6g Metol (4-methylaminophenol sulfate) * 1 litre deionized water Dissolve up first then add: * 40g. Ascorbic acid (vitamin "C") (Without the Metol, the developer will still work but is slower to act and the results may be less good.) '''Part B''' * 100g sodium carbonate anhydrous * 30g sodium hydroxide * 1 litre deionized water. (This one should be labelled "very caustic" use rubber gloves and eye protection --guard against splashing it around.) Just use equal volumes of A and B. For the 8 cm square flat glass plates, use the "floating dish" method. Two close-fitting plastic dishes are arranged so that one floats on top of the other. The volume in the lower dish should be just enough (50-60 ml) to give a minimal air gap so that the uptake of oxygen is minimised and the top dish can be used as a rocker to agitate developer over a plate. In the case of wine glasses, they can be rapidly filled to the brim with developer but because the development time needed may be only a fraction of a minute, I find it best to first wet the exposed glass with DI and then rapidly pour in roughly 60 ml of developer and then twirl the glass around while looking through it at the safelight with one eye closed to judge when the amount of darkening is sufficient as described in the next paragraph. The development does not stop by emptying the developer out into a beaker and will continue on while you are inspecting the darkening. It is stopped by giving the briefest rinse under running tap water and then pouring in the bleach solution. ==== Development Time ==== Developer TJ1 is intended to react quickly (to keep the silver grains spheroidal rather than filamentary, and to minimize damage to the gelatin in the strongly alkaline solution). So sufficient exposure level to give a development time of only 15-30 seconds should be aimed for. To judge when the time is enough if you have not had previous experience is a little tricky because it is rather subjective. Here is my method for beginners:- Take a small sample of the holographic recording material you will be using and totally expose it to bright daylight for at least 5 minutes. Then put it in developer for a minute. Then wash it well in a bowl of tap water and dry it . Now keep that piece of plate or film as a reference for your dark room. With your eyes adapted to your darkroom safelight, shut one eye and look through that piece of reference plate at your safelight.( Holographic recording material is never completely opaque). The degree of transparency or optical density of your reference plate tells you that the darkest parts of your developing hologram must never get as dark as that reference plate as judged with one eye shut. I just go for a “half as dark” subjective estimate, while holding the developing plate up to see the safelight through it. I then plunge plate into a dish under running tap water and then into a “stop bath” of 5% acetic acid, or straight into a dish of bleach solution which also contains a lot of acetic acid and oxidant which rapidly stops the development process in the plate. Ordinary room lighting can then be switched on. It is best to first wet your plate in DI before putting it in developer because it helps to even out the development over the plate area when the development is going to be rapid. If the plate in the white dish of developer appears to go black in only about 5 seconds then that means the development should be brought to a halt within about 15 seconds (allowing for that very rapid one eye inspection of the safelight). In that case do not carry on developing for a minute just because that is a more conventional developer time. More often than not, a rapid development and rapid stop in a bleach bath give the brightest results. However, if the film only starts to darken after about 15 seconds then about a 1 minute development time is probably about right in TJ1 developer but it may still need to be longer. Ideally the laser exposure times need to be sufficient to give a development time of not more than half a minute at 22C . A room temperature below 20C will however slow the whole process down. The development is stopped by first rapidly plunging plate into a big tap water bath for a second and then into a bath of the recommended bleach soln. The developer's useful lifetime with the floating dish method can be days, depending on usage. A yellow or mild brown colour means the developer is still good. When the developer is very dark brown it should be discarded. (It is the Metol constituent that is causing the brown colour when it is oxidised and it acts as a helpful indicator of exhaustion). ==== Bleaching solution ==== For reflection holograms, I find the most easily obtainable bleach is made as follows:- * 20g. Copper sulphate (CuSO4. 5H2O) * 80g. Potassium bromide (or sodium bromide) * 70 ml Acetic acid * DI to 1 litre. This is known as a rehalogenating bleach. (This is not the best for transmission holograms however). The bleach does promote grain growth, so the time in the bleach should be minimized. The bleach process should not be allowed to take much longer than about a minute. If there is a very dark area (due to over-developed up silver) that has not gone after about a minute and a half , it is best to stop the bleaching reaction anyway and wash the plate under running tap water . That still dark part will clear in the final bath used next. As this bath does not contain a lot of bromide ions there is no tendency for it to encourage more grain growth. After rinsing well under tap water, a final bath to prevent “Print Out” is needed. ==== Anti-Printout stock solution ==== “Print-out” is an old term used in photography. It means a darkening occurs in the finished photograph (hologram) in ambient lighting , particularly in sunshine. * 40 g. Sodium persulfate (or ammonium or potassium persulfate) * 40g. Sodium hydrogen sulfate * DI to 1 litre. 3 minutes in this bath followed by a very brief rinse in DI gives good print-out resistance. (Always make sure that your final rinse water is free from any traces of developer ). ==== Bleach for transmission holograms. ==== The anti-printout solution above will also work as a bleach for transmission holograms. This type of bleach is known as a “solvent bleach” which means that all the developed-up silver goes into solution and the final hologram will be made only from the original silver halide in the dark fringes that did not develop up, leaving the light fringes as just gelatin. It is very important in this type of bleach to have the developed-up plate well washed in DI before going into the bleach bath. This is because the plate has to be free of soluble bromide salt as does the bath itself. Then after the bleaching process is complete the plate should again first be rinsed in DI water before being given a final tap water rinse. The reason for this requirement is as follows. A final hologram’s diffractive efficiency relies on the refractive index difference between its light and dark fringes i.e. its fringe contrast. In the solvent bleach system the fringe contrast is got from silver halide left in the dark fringes against just gelatin in the now emptied-out light fringes. The removed dark silver metal is now ideally all in solution as soluble silver sulfate. However if any soluble halide ions were still present in the gelatin then these will combine at once with the developed-up silver as it is being oxidized to silver sulfate and the silver will be deposited back in the light fringes as silver halide where it will spoil the fringe contrast because the light fringes will not be just emptied out gelatin. In case you are wondering where soluble halide ions in the gelatin have come from, the answer is that they are always going to be produced by the developer---as the silver bromide gets converted to dark silver metal and the bromide goes into solution as sodium bromide salt. === Lasers === [[File:JBWGphoto3B.jpg|400px]] The set-up for exposing the horse hologram is shown here under HeNe light. The horse is suspended half way down the wine glass by means of a screw that passes through a metal bar which lies across the rim of the glass where it is fixed with glue-gun adhesive. The screw is made invisible by wrapping it with black flock paper. Ideally one needs to use a laser with a good coherence length. What this means in simple terms for making holograms using one beam is as follows. The diverged laser beam has to pass through the recording plate and illuminate a stable object on the other side of the plate, and then the light from the object has to pass back through the plate and form standing waves with the incoming light. These are recorded as “fringes” running inside the gelatin like the pages of a book. This forms a reflection hologram also known as a Denisyuk hologram. If the laser light were made of just one single wavelength that would be perfect because the standing wave pattern would be continuous from the plate to the object regardless of how far away the object was, provided that enough light comes back from it to form recordable light and dark fringes. However lasers are rarely so perfect and the light is usually made of a very narrow spread of wavelengths. If the object is too far back then the returning light gets out of step with the incoming light and instead of the crests and troughs of the waves coinciding they clash and fail to form the standing wave pattern. (But, at a still greater distance they do come back into step again). From the earliest days of holography, the main workhorse laser was the Helium-Neon or HeNe laser. This can give a depth of over 20 cm. in a hologram using the red 632.8 nm wavelength. However in recent years compared to the cost of a HeNe laser, incredibly cheap red laser pointers have become available and I have found that in the case of the cheapest small ones (~5 mw) I can get a surprising depth of several cm. operating in the correct mode. (A wrong mode causes striped patterns in the hologram but this effect can be temporary). The much more powerful red laser pointers with powers around 50 and 100mw., I found quite useless for holography unfortunately. [[File:JBWGhack.jpg|400px]] [[File:JBWGhack2.jpg|400px]] This shows the simple operation of hack-sawing off the lens of a small red laser pointer (~5mw) to give a very nice bar of clean light. For stability, the 3 button batteries needed to be replaced by the equivalent 4.5 volts from a large battery with the help of wired up and partially insulated croc clips. These little laser pointers operate at a much lower current than is the case for the cheap green laser pointers and therefore temperature stability is not much of a problem. With a cheap 532nm green laser pointer , I have managed to get a hologram depth of just over 3 cm once it had achieved temperature stability after a 10 minute warm-up period using the type shown below. This time after unscrewing all detachable bits and then sawing the lens off the end, I got a roughly circular spread beam, part of the other end of the barrel is also sawn off so that I could attach a variable 3 volt d.c. power supply using croc clips. It is a good idea to hold the laser in a lab clamp and stand with only bare metal on the clamps jaws (not cork or rubber) so that it will help conduct the heat away and reach an equilibrium temperature for stability. Green lasers in the photo seem to operate with a current around 0.6 amp. But if they get too hot the light output can suddenly drop very low. The original battery supplied was listed as 3.7 volts and so this value must not be exceeded and it is best to work below this voltage level. If a holographic image shows a weird stripey image, that means the laser was operating in an unfavourable mode. [[File:JBWG.jpg|400px]] Slightly changing the voltage can often make the mode O.K. but I am afraid one can be unlucky with these very cheap lasers. I am very pleased with the luck I have had so far with such cheap laser power. With the cheapest narrower pen-like green laser-pointers, operating with two AAA batteries I found I could only get a hologram depth of little more than 1 cm, but this was still enough for making gelatin holograms of coins or of slightly angled flat mirrors to make useful sensors for moisture[ii] or protease enzymes[iii]. However, for serious holographic imaging one must spend more serious money getting a laser with a guarantee that it will operate in what is known as TEM00 mode and a coherence length of over 20 cm. [i] Blyth J. et alia The Imaging Science Journal Vol 47. 87-91 (1999) [ii] Holographic Sensor for Water in Solvents Jeff Blyth · Roger B. Millington · Andrew G. Mayes · Emma R. Frears · Christopher R. Lowe Apr 1996 · Analytical Chemistry vol 68, 1089-1094 [iii] A Holographic Sensor for Proteases Roger B. Millington · Andrew G. Mayes · Jeff. Blyth · Christopher R. Lowe Dec 1995 · Analytical Chemistry vol 67 4229-4233 bc70c426f5a987ac92fd2072a08c1ae2e47f324b 2746 2745 2016-05-01T02:32:47Z Jsfisher 1 /* Anti-Printout chemicals */ wikitext text/x-wiki This is the Blyth diffusion method for making silver halide holograms on glass plates and wine glasses. [[File:JBWGphoto1.jpg|400px]] Jeff Blyth with horse hologram in wine glass == Introduction == This method is an advancement on my original system[i] where I first coated gelatin onto a glass surface and then diffused in silver salt to make it photosensitive. (This idea was then also found to be very useful to use on other pre-coated polymers). Now a real effort has been made here to make this method useable for the home-based amateur using only items purchased from the Internet or from local shops. The new “age of terrorism” has now blocked the availability of chemicals from the large manufacturers to the private addresses of peace-loving DIYers . The silver concentration used here is now three times higher than that used previously and this has raised the diffraction efficiency and much increased the photosensitivity. Previously it was found that pushing the silver concentration up to such a high level caused severe grain growth and grain growth has always been the bane of all silver halide holographic emulsion makers and even a century before them, for all emulsion makers for making Lippmann colour photographs. Here I have made 3 break-throughs in this new system. No.1: I discovered that I could greatly increase the concentration of silver ion without causing the dreaded severe grain growth phenomenon, provided that even the lowest levels of chloride ion residing in the pre-coated gelatin film could be first removed and that this could be simply done by first soaking the gelatin coating in a concentrated solution (soln) of potassium or sodium nitrate causing an ion exchange mechanism. No.2: I found that if I made my gelatin “emulsion” with silver chloride (AgCl) rather than the conventional silver bromide (AgBr), I was able to increase the photosensitivity by a factor of 3. The hologram still finishes up made in the conventional higher diffracting AgBr because I use a conventional bleach formula containing bromide ions. No.3: there is usually something present in shop-bought culinary gelatin which causes a degree of chemical fogging in the development step and that this could be prevented by simply adding a small quantity of copper sulphate to the gelatin soln prior to coating the film. [[File:JBWGphoto2.jpg|400px]] By pre-swelling before the exposure is made with a HeNe red laser, the holographic horse is yellow rather than red. By preswelling still more the horse image is green as in above photo == Chemicals available from the Internet == The first 2 on this list are especially important to be the purest you can get off the Internet. The rest are less critical but should be better than 90% pure if possible. Some of these chemicals will be used for making up the developer and bleaching solution later after the plates are made. The chemistry there will be dealt with in a separate section. '''Silver nitrate (AgNO3)''' This is available in 10g quantities. It needs to be as pure as possible via AMAZON or eBay. '''Potassium Nitrate''' “Food Grade” via eBay or AMAZON. “Food Grade” has worked OK. But it does have the disadvantage of containing an anti-caking agent. When a 10% solution is initially made up, this agent causes haziness instead of making a completely clear solution (soln). This haze will also stain the finished gelatin film. So one must make up the soln well in advance before use, then allow the agent to settle out and then carefully decant off the upper clear soln into another bottle. High purity sodium nitrate would be best but most offers are of lower purity than the food grade potassium salt, the offers also are confused with the completely unsuitable sodium nitrite. '''Sodium Chloride.''' Normal supermarket grade seems to be OK here. Even though it may contain small amounts of an anti-caking agent such as sodium ferrocyanide. '''Chromium Potassium Sulphate (or Sulfate)''' via AMAZON or eBay. This should be a purple powder . It is also called Chrome Alum. The green powder sold as Chromium sulfate (basic) is not suitable. Straightforward “Alum” or aluminium potassium sulphate is apparently useless as a gelatin hardener for us here. '''Acridine Orange''' via eBay (but not AMAZON). This is listed as “microbiological stain”. A bottle of 5g listed as “50%” from APC has worked well for use with a 532nm laser pointer .(Unfortunately the dye needed for red lasers I have only managed to get direct from Sigma-Aldrich or other big chemical companies , see section 19). '''Methanol''' 1 litre via AMAZON or eBay. '''Copper sulphate or sulfate.''' The blue crystals are easier to obtain than the white anhydrous compound, so my formulations are based on using the blue pentahydrate from eBay or AMAZON. === Developer chemicals. === '''Ascorbic acid (pure vitamin C powder).''' Ubiquitously available. '''Metol''' From eBay '''Sodium Carbonate anhydrous.''' From eBay, (this must not be the very impure “washing soda” crystals). '''Sodium Hydroxide''' from eBay. A quite good grade is needed, (not the one sold just for clearing drains). === Bleach Chemicals === '''Copper sulphate (sulfate)''' (already listed above) '''Acetic acid''' from eBay Potassium Bromide 200g analytical grade, available via AMAZON === Anti-Printout chemicals === (“Print-out” is an old term used by photographers. It means a darkening occurs in the finished photograph (or hologram) in sunshine or bright lighting. AgCl exhibits the effect more strongly than AgBr. Here holograms made from emulsions that originally contained AgCl rather than AgBr are more liable to print-out even though they finish up being made mostly of AgBr, they still retain some AgCl. So an anti print-out step is important.) '''Sodium persulfate (or ammonium or potassium)''' from eBay. '''Sodium hydrogen sulfate (sulphate)''' from eBay '''Glass sheets.''' These are referred to here as “sheets” when buying the glass and “plates” when being turned into hologram recording material. It is convenient to use thin glass sheets of 2mm thickness for making small holograms up to say 5 x 4 inches for ease of cutting. However thicker glass is probably necessary for larger ambitious holograms because thin sheets can bow during exposure in a horizontal set-up. I find it very convenient to use those 10 cm square disposable laboratory weigh boats (from the Internet) as dishes to hold the solutions needed to process an exposed hologram. The great feature of these boats is that when they contain about 60 ml (but not more) of developer, another boat can float on top and this can effectively keep the developer active for many hours whereas in an open uncovered dish oxygen absorption will exhaust the developer in about half an hour. Also although the other dishes needed are not all affected by oxygen, they can be affected by evaporation, so such lids are used on them too. [[File:JBWPDishes.jpg|400px]] Disposable 10 cm square weigh-boats used as trays to hold developer and bleach. A second tray acts as a floating lid to delay oxidation and evaporation. To accommodate to these dishes I have been purchasing plates 2mm x 240mm x 160 mm. This is a convenient size for the gelatin coating procedure and is convenient for cutting into six 80 mm square plates that are a nice size for fingers to place in, and then take out of the dishes. Of course those fingers should be rubber-glove-covered. I also purchased 1 or more “carrier” sheets . These sheets were 4 mm x 270mm x 190mm. These thicker glass sheets allowed one to place the thinner glass on top with a 3 cm. border all round. “Subbing” the glass. Failure of gelatin film to adhere reliably to the glass surface can be a major problem. A common way to get adhesion is to use certain silane compounds which cause attraction chemically to the silica constituent of ordinary glass. However I have tried 3 different brands of “silane” off the Internet which were sold as aids to help bonding when using epoxy resins. These were not fully satisfactory as they frequently failed to do the job. I found a better answer to this problem was as follows. I leave the glass sheets for half an hour or more in 100% domestic bleach. I then rinse them in running tap water while wiping them well with a cloth. I then mark the back of the 2 mm glass sheet with a black “permanent” marker pen with say a “B”. (If there happened to be a scratch on one side of the glass then that should be the side that will be gelatin coated, as the gelatin film will later hide the scratch). I then hold the sheet at an angle of about 45degrees and place a clean collecting tray at the bottom end. I then pour a very dilute solution of gelatin and chromium potassium sulphate (detailed below) all over the front of the tilted plate. Although quite dilute, the gelatin content in the soln is sufficient to reduce the surface tension enough to allow a film to form, rather than form droplets. This plate is then left to dry leaving a very thin film of gelatin and chromium salt. Once dry, the sheet was placed with the treated side face-up into a preheated oven at 190-200C for about half an hour. The gelatin soln for this subbing was a diluted form of the gelatin soln used to make the main coating soln detailed below. So 5 ml of the soln detailed below was added to 100 ml of warm water and then 5 ml of stock chromium potassium sulfate soln. was added. This stock chromium soln was 4% soln. of chromium potassium sulfate and 4% glycerol. Stock Gelatin coating solution 1) I prepare a stock solution of shop-bought leaf gelatin of 12 g. in 100ml of cold deionized water. This is then placed in a water bath to prevent the gelatin getting over-heated. A thermometer is used in the inner gelatin bath to check that the temperature does not rise above 51 oC , while being constantly stirred for about 20 minutes or more. This is then filtered through a cotton handkerchief or nylon stocking to remove any froth from the surface About 0.5g copper sulphate CuSO4.5H2O is then added to about 3 ml deionized or distilled water, (DI) and the soln is then stirred into the gelatin soln. (There is often something in the shop bought gelatin that is inclined to cause mild chemical fogging. Also if the gelatin soln is over-heated this chemical fogging can become severe. This term “fogging “ is not related to the terms “haziness” or “scatter” mentioned later. “Chemical fogging” is a term used in photography to mean a degree of darkening (caused by fine silver metal grains) in developer not caused by light. 2) About 4ml of glycerol is then stirred in. I then pour it all into a clean bottle with a screw cap. Prior to coating I heat this stock solution up to 50 oC max. in a warmer. 3) I then take 2 glass sheets , one is 2mm x 240mm x 160 mm. (This size is convenient for cutting into six 80 mm square plates that will fit into those disposable 10 cm square weigh boats) . I use a 4mm thick glass sheet to act as a carrier sheet. The carrier sheet is 4 mm x 270mm x 190mm and the first glass sheet is placed on it, to make a margin of about 3 cm all the way round. Using PVC insulation tape, the thinner glass sheet is then taped down onto the carrier sheet with about 3mm of tape covering the perimeter of the thin sheet. I then place both this sheet combination and a clean plastic tray in the warmer together with the gelatin solution so that everything gets to 50 oC [[File:JBWPb3.jpg|400px]] A 2mm thick glass sheet is taped onto a larger 4mm thick "carrier" sheet. 4) I then take out the warmed sheets and put them in the tray on a horizontal surface . Then working quickly I pour roughly 20 ml of the gelatin soln. onto the centre of the thin glass sheet and quickly spread the gelatin puddle all over the sheet by hand so that the whole area of the sheet is wetted by the gelatin soln. I then quickly lift up one end of the sheet pair leaving the other end in in the warmed plastic tray and incline the sheet at an angle of about 45 degrees and pour the rest of the gelatin across the top end so that it all runs down smoothly as I move the bottle across the top. I then lift the sheets up off the tray so that excess gelatin drips off the bottom for no more than 15 sec. (If the initial wetting with the gelatin solution had not been carried out then the poured film would not have properly covered the sheet evenly). 5) I then quickly place the sheets on a cool flat horizontally correct surface, free from strong air currents. 6) I then pour the remaining gelatin in the tray back into the bottle, screw on the lid lightly and put the bottle back in the oven at 50oC. for about 5 minutes before screwing on the lid tightly and storing the bottle at room temperature for re-use at a later date. (So far I have had no sign of any moulds growing after leaving the gelatin soln. at room temperature for 6 months like this). 7) When the gelatin film has gelled, I then remove most of its water content by leaving the sheet in a good flow of room temperature air from a fan. 8) When the gelatin film is touch dry I run a scalpel blade around the tape border to avoid any gelatin being torn off the glass when I remove the tape before the next step. 9) With the tape peeled off, and the gelatin touch dry I then place just the coated sheet in a clean tray, and pour over its surface a chilled soln (at~5oC) of previously made 4% chromium potassium sulfate with 4% glycerol. After about a minute, I remove the sheet and shake it, the sheet is very soft and vulnerable at this point, so I very gently touch any droplets still on the gelatin face with a tissue, and also wipe off the back of the sheet. I then stand the sheet up and leave it drying in front of a fan with a good air flow. Meanwhile I pour the chromium soln in the tray back into its storage bottle and keep it in a fridge for further use. (If the chromium soln later loses its purple colour and starts to look greenish then it should not be re-used). It is then left in a cold airflow overnight. (The gelatin hardening by the chromium salt only really takes place when the gelatin film is in a relatively dry and unswollen state. An oven or warmer at 50 oC could be used instead to speed the slow process up to about an hour, but the gelatin film MUST firstly be made dry under a cold blower before being put in a warmer). If the room is below 20 oC it is best to use the warmer anyway, otherwise the slow hardening process may still be incomplete after 12 hours. 10) I then rinse the sheet front and back in running tap water and then with 3 changes of DI water. (Unlike the notorious dichromate which is (CrVI), it is OK here to let a small amount of this form of chromium (CrIII) go down the drain). 11) The sheets are then left in a bath of 0.10% sodium carbonate for about 2 minutes only and then briefly rinsed in DI. (Making the gelatin slightly alkaline contributes greatly to its ability to bind silver ions later). 12) The sheets are then left for several hours or overnight in a 10% soln. of pure sodium or potassium nitrate for the essential process of removing any chloride ions by a slow ion exchange mechanism. This time can be cut down to about an hour if the solution can be continuously mechanically agitated. The soln can be reused a number of times, depending on the amount of Cl ion it has exchanged for NO3 ion. Note that if the nitrate is from “food grade” potassium nitrate it should be a clear solution that has been decanted off from a whitish precipitate of anti-caking agent that has been allowed to settle out from an initially hazy solution. 13) The sheet is then rinsed well in DI and dried in a cold air flow so that it will be ready to allow silver nitrate to diffuse in. N.B. I have to be very careful to avoid any contamination from traces of chloride ions on the wet gelatin at this point. e.g. from tap water splashes, fingers, sneezing over it or forcefully pronouncing words with the letter “P”!!! (Otherwise tiny amounts of AgCl produced from stray Cl ions will grow into horrible big white grains in step 20 later.) 14) A concentrated stock soln. of silver nitrate (AgNO3) is prepared by making a solution of 10g of silver nitrate crystals to 50 ml of DI water in an ultra-clean bottle with lid. (This relatively expensive solution is very vulnerable to contamination. As well as any chloride or bromide traces, I am very careful not to allow any paper tissue particles to get into the stock bottle as such organic stuff can cause the soln to go brown due to colloidal silver formation, which can cause bad fogging during the development of the plates. ). 15) I then use the thick glass carrier sheet (carefully cleaned and free from halide traces) as a flat surface to coat the gelatin film with the silver nitrate solution by a puddle method . The room lighting does not need to be at a low traditional darkroom “safelight” level at this point. A low wattage tungsten filament bulb (eg. around 15W) is OK but not fluorescent “daylight” lighting. Using a clean syringe or pipette, I deposit a certain sized blob of silver nitrate soln. close to an edge of the carrier sheet. I then carefully place a cut piece of the gelatin coated sheet on top of the blob so that about a half to one cm. of the sheet protrudes over the edge of the carrier glass. The blob of silver nitrate soln then spreads evenly and easily over the gelatin film by capillary action except of course for the bit protruding over the edge of the thick carrier sheet. This overhang bit is useful for handling the sheet without touching the silver nitrate. The AgNO3 is allowed to soak in for about 2 minutes only. The size of the blob is roughly as follows; for an 8 cm square plate, my blob is made from about 0.8ml of the Ag solution. (Remembering that each 1ml blob will perhaps have cost you nearly a dollar in 2016). The puddle coating system usually works particularly well if the carrier sheet is first treated with “Rain-X” which is obtainable from suppliers of automobile sundries. This stuff makes the carrier glass water-repellent and helps to restrict the silver nitrate solution from straying beyond the thin glass sheet boundary). 16) The gelatin film then needs to have any AgNO3 soln. on the surface to be wiped off with care. A small car windshield wiper blade can be used as a squeegee and the rubber washed clean in DI after each use. Alternatively a clean doubly folded tissue folded over a ruler can be used as the wiper blade but using only one quick single wipe per tissue. (The tissue may contain low amounts of Cl- which could flow into the gelatin if more than a quick single wipe is used). 17) The plate is finally dried in a cool air flow, I check to see that there is no scatter at this point. If there is just the slightest mild scatter over the plate at this point then the plate should be discarded, (unless it was just caused by that anti-caking agent in KNO3). Because it means there was still some chloride ion contamination in there and the scatter will get much amplified in the step using a chloride and dye bath in section 20. If there is scatter in just a small part of the plate area then that probably means some chloride or bromide contamination from handling fingers that had been in tap-water, but it may be worth continuing by ignoring a small scattery area around the edge. Preparation of stock sodium chloride and dye solutions. 18) I prepare a 1 litre soln as follows. I add 41g. sodium chloride (NaCl) to a 1 litre bottle and add 334 ml of water, then after it has dissolved, I pour in 666 ml of ethanol or methanol. This makes a 2:1 alcohol : water soln. (These quantities do not have to be that precise, even a 10% error will probably be OK). 19) For the 8cm square plates, I take a 100ml of the stock NaCl soln. and add 2 ml of stock dye soln , then I use about 70 ml of this soln in one of those 10cm square dishes . The stock dye solutions are made as follows. For green lasers I prepare 0.5g of Acridine Orange (A.O.) per 100 ml of a 2:1 ratio of alcohol :water. The A.O. I got off the Internet is described as “50%” acridine orange.—It has worked well. For red lasers I use pinacyanol chloride, (its old name was “quinaldine blue” ). I prepare a stock soln of 0.3g of pinacyanol chloride in 100ml ethanol or methanol, (pinacyanol bromide or iodide can be used instead). It is most regrettable that I have not managed to buy this dye on the Internet as an ordinary citizen yet. This is the one item that I have had trouble with. A Chinese company does offer pinacyanol iodide on the Internet but the shipping costs quoted for just 1 gram are utterly ridiculous. So my dye had to be bought professionally from Sigma-Aldrich). 20) So to make my plate photosensitive I now have to work under an appropriate safelight; dim green for making red sensitive plates and dim red for making green sensitive plates. The safelight does not need to be as dim as was used for traditional photographic darkrooms where much more photosensitive material was used. One can get an idea of how much light of the wrong colour is coming out from your safelight from looking at the rainbow spectrum you get off the surface of any DVD held in the area of the room where you are working. I find that the “REMOTE CONTROLLED AUROGLOW” bulbs obtainable via AMAZON are excellent as safelights as they have instantly selectable colour and brightness . 21) I take the dried plate containing the AgNO3 and plunge it quickly into the chloride/dye bath for 45 seconds , agitating it constantly. (The time in this bath governs the grain growth. If it is too long the grain growth can get unacceptable, whereas if it is too short then a lot of silver nitrate could remain unconverted to silver chloride). After the 45 seconds I then without delay plunge the plate into a dish under cold running tap water and I leave it in for at least a couple of minutes or more. 22) Then the plate is inspected under reflected safelight. It must look scatter free or at least only show a very slight haziness . If there is bad scatter then the probable cause is a failure to remove traces of chloride ion effectively from the gelatin before the silver nitrate soln was applied. If the scatter is slight then it may be worth continuing anyway. Scatter just around some of the edges is quite likely to occur due to increased thickness and handling. The edges should not be included in the final holographic image anyway. Accidental areas of much greater thickness may also still contain unconverted silver nitrate. Such areas will turn rapidly black due to a deposit of silver metal when they meet the sensitizing bath of 2% ascorbic acid discussed in the next paragraph. They would also fog badly in the final development step of course. If one tries to eliminate any unconverted silver nitrate in accidentally thick areas around the edges by prolonging the time spent in the halide/dye bath, then an increased level of grain growth occurs in the thinner areas that are OK after just 45sec. of immersion only. The best one can do if unconverted AgNO3 is still thought to be lingering in thickly coated areas is to prolong the time in the running tap water, e.g. for 10 minutes, (the water should be as cold as possible). To maintain a final replay colour close to that of the laser wavelength, I then put the plate in a bath of 2% ascorbic acid (vitamin C) that has been taken to a pH of between 5 and 6 with sodium hydroxide. (If you have not got pH paper available then carefully weigh out 2.0 g vitamin C and dissolve it in 100 ml of DI. Then add 0.38g sodium hydroxide). Without this vitamin C treatment the light sensitivity of the plate is very low. I then wipe off the droplets with a tissue or give the plate the briefest rinse in DI. (I like to leave a trace of ascorbate in the plate as it helps to maintain its photosensitivity). 23) If I want to make bright green holograms from a red laser, then I must not use the ascorbate bath but instead I immerse the plate in a bath of 15% triethanolamine or ”TEA” for about a minute. (Treating with both ascorbate and TEA causes chemical fogging or darkening without light involvement). 24) I then carefully wipe the surface free of droplets using either a wiper-blade squeegee or doubly folded tissue over a ruler similar to that used for the earlier AgNO3 treatment, (but now I do not have to worry about any contamination from chloride ions). 25) I then leave the plate under a cold air blower for 20 minutes to acclimatize with ambient humidity. It is then best to leave the plate in a cardboard dark box until the next day when you are making larger holograms because the gelatin surface is probably not going to be stable enough for longer exposure times of more than say 4 seconds. However you will probably want to at least make some necessary exposure tests on small plate pieces before that. I find it best to do initial tests on a glass top table with the spread laser beam coming up from underneath the table or any frame able to hold a horizontal glass sheet. Initially it is best just to make a photographic exposure test. With the beam shuttered I place a piece of my recording plate on top of some masked off area , such as the piece of negative with lettering on it in the image below hat had been put in the beam before it was shuttered. The laser exposure times need to be sufficient to give a development time of about half a minute or less at 22C (see below under “Development Time” discussion). The “photographed” unmasked off area should look quite dark whereas the masked off area should be no more than slightly dark, ( if it is nearly as dark as the unmasked area than that means that I have a fog problem either caused by stray light or chemistry in the gelatin). [[File:JBWPb1.jpg|400px]] This is the rig I use for initially testing newly made hologram recording plate. A sheet of 5mm thick glass rests over a frame of a stool. Under the glass sheet I have a 4 mw red laser pointer sitting in a glass jar. The laser has been treated as per the images below. The beam is shuttered off with a piece of black card stuck to an upturned plastic beaker. On top of the glass are various objects for making exposure tests. I often start with making just a photographic image of a piece of film negative with lettering by placing the lettering in the centre of the beam and then with the beam shuttered I put a piece of plate ontop of the negative for an exposure test. To make holographic tests I place objects ontop of a piece of plate and give them time to settle before exposing. The aluminium cups are useful for putting over objects so that more laser light can be used to illuminate the sides of an object provided the laser has enough coherence length (see final section "Lasers"). This simple set-up is very good for making simple holograms in unstable environments. For a holographic test, the beam needs to be almost but not exactly perpendicular to the plate to make the traditional test with polished coins. With the beam shuttered, the coins are placed on top of the recording plate preferably on the glass side of the plate, and left for at least 10 minutes to settle. A newly made gelatin film may contract by a nanometre or two during exposure while it is thus sandwiched between the 2 glass sheets but simple coin holograms can still be obtainable because the coin to “emulsion” distance should stay the same at least for most of the emulsion attached to the plate’s glass. The important point about this test is to see how quickly the exposed hologram takes to darken in a developer such as TJ1 (see below). This glass table top system is excellent for making holograms in an unstable environment because the plate and object can “ride the storm” together. == Coating Curved glass surfaces such as wine glasses. == [[File:JBWGphoto3.jpg|400px]] Martini glass with cut-off stem to afford possibility of constrcting a hologram with an all-round view Wine-glasses have the very convenient property of being able to act as their own processing baths. It is best to do several glasses at the same time. I recommend getting 2 packs of 4 cheap plain wine glasses of about 250 ml (cc.) capacity. I first fill the glasses to the rim with either undiluted or 50% diluted domestic bleach solution. The bleach is left in each glass for about 15 minutes or longer. The bleach is then poured back into a bottle for re-use, and the glasses are rinsed well in running tap water and wiped around with a cloth before being given a rinse in DI. Each glass is then coated with the subbing layer described above under the title “Subbing the glass” but this time more conveniently, the subbing solution is poured into the glass and the glass is then tilted so that the soln wets the side of the glass up to the rim and the glass is then rotated so that the whole glass is wetted, the soln is then poured into the next warmed glass and so on. The treated glasses are then left standing in an airflow so that the very thin subbing film gets dry. The glasses are then placed in a preheated oven at 190-200C for about a half-hour. They are then allowed to cool and are given a rinse in DI. The glasses are then placed in a warmer at 50 C to dry. The bottle of stock gelatin solution should also be in the warmer and also a plastic or glass beaker with a spout. A typical wine glass holds about 250 ml. of soln. So I take 100 ml (or it can be less) of the 50 oC gelatin stock solution prepared as previously described and I pour it carefully and slowly into the warm beaker while trying to avoid creating any bubbles. The beaker is then used to carefully pour the gelatin soln into the wine glass without creating bubbles, (the spout makes this requirement easier than pouring straight from the warm stock bottle). The wineglass is then tilted and rotated so that the inside is all wetted by the soln up to the rim of the glass. The gelatin is then poured slowly from the glass back into the beaker trying to again avoid creating bubbles. The glass is then upturned and placed on a clean surface allowing the gelatin solution to flow down to the rim before gelling at room temperature. Meanwhile the beaker of gelatin soln is poured into the next glass at 50 oC and so on. The soln in the beaker should not be allowed to drop below say 40 oC or it may get too viscous to coat properly. (I do not recommend using a few seconds in a microwave oven to reheat it as I find that it can damage the gelatin and cause fogging later). Once the glass is cold and the gelatin film has gelled, then just the rim of each glass is carefully dipped into a bath of warm water to remove that thick gelatin layer around the rim. I try to not let this water level go higher than about 3 mm up from the rim. The glass is then still held in an upturned position and just the rim is wiped free of water droplets so that these droplets will not run down into the glass when it is placed upright. The upright glasses are then placed in a strong cool air current to remove the excess water in the gelatin. Once the gelatin film is unswollen (except for the partial swelling caused by the glycerol present), it is ready for the hardening solution to be poured in. The hardening soln is as described previously. Namely 4% chromium potassium sulfate soln with 4% glycerol chilled to about 5 oC. This solution is swirled around the wineglass so that it wets all the gelatin film and is then emptied into the next wineglass and so on. If the chromium soln has not run down the sides of the glass evenly when the glass is stood upright then any droplets should be gently removed by just touching with a paper tissue (do not wipe as the gelatin is very soft at this point), as only the absorbed chromium solution is wanted and droplets can cause a mark on the surface later. The wineglasses are then left upright in a cool airflow for several hours to harden. This hardening process is slow and if the room is particularly cold overnight say then it is best in the morning to warm the glass in a warmer at 50 oC for 20 minutes or more, or with a hairdryer at about 50 oC for a few minutes to finish off the hardening process. Any excess chromium salt is then removed under cold running tap water. [Unlike the notorious dichromate which is (CrVI), it is OK to let a small amount of this form of chromium (CrIII) go down the drain]. The glass is then shaken free of tap water droplets and rinsed at least three times with DI. Each glass in turn is then filled to the brim with a 0.1% solution of sodium carbonate for about 1 to 2 minutes and is then rinsed briefly in DI. Now follows the vital step of removing traces of chloride ions from the gelatin film. Each glass is filled to the brim with about a 10% solution of potassium or sodium nitrate. They are then left for several hours for the ion exchange process to occur. (Cl exchanged for NO3). The nitrate solution is then poured back into a bottle where it is probably reusable several times more. The glasses are then rinsed in DI three times and left in a warm air-flow. When dry they are ready for loading up with the silver soln. === Diffusing in silver nitrate solution === For your first wine-glass experiments it is best to only expose one side of the wine glass and therefore you should only put your expensive silver solution on one side of the glass. Covering the whole glass with silver causes real complications for an object such as a model figurine, because it will record a photographic shadow on the opposite side of the glass. It will also record spurious rainbow coloured effects due to transmission type gratings. However, it is worth covering the whole glass with silver solution if you want to just do a simple hologram of the glass filled to the brim with say coins. Then 2 exposures can be made 180 degrees apart and each exposure will not be affected by an exposure on the opposite side of the glass. So for making a reflexion hologram on one side of the glass only, you need to first decide which half of the coating looks the best to use and then use a marker pen to put a cross on the other side that you do not want to use. To put the silver solution into one half of the gelatin film you need a new disposable rubber glove at least on one hand. Using a 1 ml clean plastic syringe take 0.5 ml of the silver nitrate solution, and holding the glass horizontally with the future image side down, gently empty the syringe onto that concave surface. Then use your gloved forefinger to wipe the silver solution only over that designated half of the glass. Spend at least 2 minutes gently wiping that solution over just that half of the glass. At first it might seem that the solution is not wetting the film surface well and is forming droplets. However as you work at rubbing it into the gelatin, the gelatin’s surfactant properties start to kick in and the silver soln spreads more easily. This operation can be done in subdued ambient lighting such as that from a 25W or 15W tungsten filament bulb, there is no need for a proper safelight at this stage but it is vulnerable to fluorescent or blue-rich lighting. Once the gelatin layer has absorbed the silver solution, it is important to remove any excess solution off the surface or it will scar the finished hologram. I use a folded tissue to gently wipe the gelatin surface free of solution. Only use the tissue for one single quick wipe then throw it away and use another clean tissue if needed. If you plan to use the whole glass for 2 images on opposite sides then you will need to use 1.0 ml of silver nitrate soln and spend at least 3 minutes rubbing the solution over the whole surface before wiping off the excess with tissues. The glass should now look clear and scatter-free at this point, a hairdryer is now needed to dry it in a tepid airflow because it must be fairly dry for the next step, but a hot blow must not be used. === Sensitizing the gelatin film. === '''Suitable safe lighting is now needed for the next steps.''' The average wine-glass will take 250 ml of liquid. So it can be convenient to pour say 300 ml of the stock sodium chloride (section 18 above) into a beaker and add about 6ml of the stock dye solution (section 19). Then about 250 ml of it can be '''''rapidly''''' poured into the wineglass and left in for only 45 seconds and then quickly poured back into the beaker and the glass then put into running tap water with minimal delay. A beaker should be used each time for each glass rather than pouring from one glass to the next. The timing here is important because if it is too short , not all the silver nitrate in the gelatin will be able to be converted to silver chloride and if it is too long there will be quite rapid grain growth. The thickness of the gelatin layer is also a factor in determining the optimum time. To stop the reaction of the sodium chloride solution, the glass is filled rapidly with running tap water and left in the water for several minutes. It is then shaken free of tap water and given a brief rinse in de-ionized water and then filled with about 3% vitamin C solution that has been taken to a pH of between 4.5 and 5 with sodium hydroxide or with sodium carbonate (a pH of over 7 acts as a developer and will cause chemical fogging) the glass is then given a brief DI rinse and left to dry in a good cool air flow. If you wish to use a red laser to make bright yellow-green holograms then the ascorbic acid treatment should not be used and should be substituted with a soln of 12% TEA. After a minute or two in this TEA solution, the gelatin surface should be gently wiped with tissues so that no droplets or rivulets remain. The outside of the glass should be wiped too of course so that it is smear free. The photosensitive glasses should then be dried in a good air flow and left to equilibrate in a light-tight cardboard box or cupboard. They should not be used till at least a day has passed because the gelatin layer will probably be quite unstable for many hours. ==== The Developer ==== It is most convenient to have a 2 part developer in two one litre bottles labelled A and B. The developer can keep indefinitely in these separate bottles. They are then used by mixing equal volumes. The developer below has been christened “TJ1” developer. (In honor of the late Tung Jeong who asked me to make a suitable developer some years ago for teaching his students). '''Part A''' * 6g Metol (4-methylaminophenol sulfate) * 1 litre deionized water Dissolve up first then add: * 40g. Ascorbic acid (vitamin "C") (Without the Metol, the developer will still work but is slower to act and the results may be less good.) '''Part B''' * 100g sodium carbonate anhydrous * 30g sodium hydroxide * 1 litre deionized water. (This one should be labelled "very caustic" use rubber gloves and eye protection --guard against splashing it around.) Just use equal volumes of A and B. For the 8 cm square flat glass plates, use the "floating dish" method. Two close-fitting plastic dishes are arranged so that one floats on top of the other. The volume in the lower dish should be just enough (50-60 ml) to give a minimal air gap so that the uptake of oxygen is minimised and the top dish can be used as a rocker to agitate developer over a plate. In the case of wine glasses, they can be rapidly filled to the brim with developer but because the development time needed may be only a fraction of a minute, I find it best to first wet the exposed glass with DI and then rapidly pour in roughly 60 ml of developer and then twirl the glass around while looking through it at the safelight with one eye closed to judge when the amount of darkening is sufficient as described in the next paragraph. The development does not stop by emptying the developer out into a beaker and will continue on while you are inspecting the darkening. It is stopped by giving the briefest rinse under running tap water and then pouring in the bleach solution. ==== Development Time ==== Developer TJ1 is intended to react quickly (to keep the silver grains spheroidal rather than filamentary, and to minimize damage to the gelatin in the strongly alkaline solution). So sufficient exposure level to give a development time of only 15-30 seconds should be aimed for. To judge when the time is enough if you have not had previous experience is a little tricky because it is rather subjective. Here is my method for beginners:- Take a small sample of the holographic recording material you will be using and totally expose it to bright daylight for at least 5 minutes. Then put it in developer for a minute. Then wash it well in a bowl of tap water and dry it . Now keep that piece of plate or film as a reference for your dark room. With your eyes adapted to your darkroom safelight, shut one eye and look through that piece of reference plate at your safelight.( Holographic recording material is never completely opaque). The degree of transparency or optical density of your reference plate tells you that the darkest parts of your developing hologram must never get as dark as that reference plate as judged with one eye shut. I just go for a “half as dark” subjective estimate, while holding the developing plate up to see the safelight through it. I then plunge plate into a dish under running tap water and then into a “stop bath” of 5% acetic acid, or straight into a dish of bleach solution which also contains a lot of acetic acid and oxidant which rapidly stops the development process in the plate. Ordinary room lighting can then be switched on. It is best to first wet your plate in DI before putting it in developer because it helps to even out the development over the plate area when the development is going to be rapid. If the plate in the white dish of developer appears to go black in only about 5 seconds then that means the development should be brought to a halt within about 15 seconds (allowing for that very rapid one eye inspection of the safelight). In that case do not carry on developing for a minute just because that is a more conventional developer time. More often than not, a rapid development and rapid stop in a bleach bath give the brightest results. However, if the film only starts to darken after about 15 seconds then about a 1 minute development time is probably about right in TJ1 developer but it may still need to be longer. Ideally the laser exposure times need to be sufficient to give a development time of not more than half a minute at 22C . A room temperature below 20C will however slow the whole process down. The development is stopped by first rapidly plunging plate into a big tap water bath for a second and then into a bath of the recommended bleach soln. The developer's useful lifetime with the floating dish method can be days, depending on usage. A yellow or mild brown colour means the developer is still good. When the developer is very dark brown it should be discarded. (It is the Metol constituent that is causing the brown colour when it is oxidised and it acts as a helpful indicator of exhaustion). ==== Bleaching solution ==== For reflection holograms, I find the most easily obtainable bleach is made as follows:- * 20g. Copper sulphate (CuSO4. 5H2O) * 80g. Potassium bromide (or sodium bromide) * 70 ml Acetic acid * DI to 1 litre. This is known as a rehalogenating bleach. (This is not the best for transmission holograms however). The bleach does promote grain growth, so the time in the bleach should be minimized. The bleach process should not be allowed to take much longer than about a minute. If there is a very dark area (due to over-developed up silver) that has not gone after about a minute and a half , it is best to stop the bleaching reaction anyway and wash the plate under running tap water . That still dark part will clear in the final bath used next. As this bath does not contain a lot of bromide ions there is no tendency for it to encourage more grain growth. After rinsing well under tap water, a final bath to prevent “Print Out” is needed. ==== Anti-Printout stock solution ==== “Print-out” is an old term used in photography. It means a darkening occurs in the finished photograph (hologram) in ambient lighting , particularly in sunshine. * 40 g. Sodium persulfate (or ammonium or potassium persulfate) * 40g. Sodium hydrogen sulfate * DI to 1 litre. 3 minutes in this bath followed by a very brief rinse in DI gives good print-out resistance. (Always make sure that your final rinse water is free from any traces of developer ). ==== Bleach for transmission holograms. ==== The anti-printout solution above will also work as a bleach for transmission holograms. This type of bleach is known as a “solvent bleach” which means that all the developed-up silver goes into solution and the final hologram will be made only from the original silver halide in the dark fringes that did not develop up, leaving the light fringes as just gelatin. It is very important in this type of bleach to have the developed-up plate well washed in DI before going into the bleach bath. This is because the plate has to be free of soluble bromide salt as does the bath itself. Then after the bleaching process is complete the plate should again first be rinsed in DI water before being given a final tap water rinse. The reason for this requirement is as follows. A final hologram’s diffractive efficiency relies on the refractive index difference between its light and dark fringes i.e. its fringe contrast. In the solvent bleach system the fringe contrast is got from silver halide left in the dark fringes against just gelatin in the now emptied-out light fringes. The removed dark silver metal is now ideally all in solution as soluble silver sulfate. However if any soluble halide ions were still present in the gelatin then these will combine at once with the developed-up silver as it is being oxidized to silver sulfate and the silver will be deposited back in the light fringes as silver halide where it will spoil the fringe contrast because the light fringes will not be just emptied out gelatin. In case you are wondering where soluble halide ions in the gelatin have come from, the answer is that they are always going to be produced by the developer---as the silver bromide gets converted to dark silver metal and the bromide goes into solution as sodium bromide salt. === Lasers === [[File:JBWGphoto3B.jpg|400px]] The set-up for exposing the horse hologram is shown here under HeNe light. The horse is suspended half way down the wine glass by means of a screw that passes through a metal bar which lies across the rim of the glass where it is fixed with glue-gun adhesive. The screw is made invisible by wrapping it with black flock paper. Ideally one needs to use a laser with a good coherence length. What this means in simple terms for making holograms using one beam is as follows. The diverged laser beam has to pass through the recording plate and illuminate a stable object on the other side of the plate, and then the light from the object has to pass back through the plate and form standing waves with the incoming light. These are recorded as “fringes” running inside the gelatin like the pages of a book. This forms a reflection hologram also known as a Denisyuk hologram. If the laser light were made of just one single wavelength that would be perfect because the standing wave pattern would be continuous from the plate to the object regardless of how far away the object was, provided that enough light comes back from it to form recordable light and dark fringes. However lasers are rarely so perfect and the light is usually made of a very narrow spread of wavelengths. If the object is too far back then the returning light gets out of step with the incoming light and instead of the crests and troughs of the waves coinciding they clash and fail to form the standing wave pattern. (But, at a still greater distance they do come back into step again). From the earliest days of holography, the main workhorse laser was the Helium-Neon or HeNe laser. This can give a depth of over 20 cm. in a hologram using the red 632.8 nm wavelength. However in recent years compared to the cost of a HeNe laser, incredibly cheap red laser pointers have become available and I have found that in the case of the cheapest small ones (~5 mw) I can get a surprising depth of several cm. operating in the correct mode. (A wrong mode causes striped patterns in the hologram but this effect can be temporary). The much more powerful red laser pointers with powers around 50 and 100mw., I found quite useless for holography unfortunately. [[File:JBWGhack.jpg|400px]] [[File:JBWGhack2.jpg|400px]] This shows the simple operation of hack-sawing off the lens of a small red laser pointer (~5mw) to give a very nice bar of clean light. For stability, the 3 button batteries needed to be replaced by the equivalent 4.5 volts from a large battery with the help of wired up and partially insulated croc clips. These little laser pointers operate at a much lower current than is the case for the cheap green laser pointers and therefore temperature stability is not much of a problem. With a cheap 532nm green laser pointer , I have managed to get a hologram depth of just over 3 cm once it had achieved temperature stability after a 10 minute warm-up period using the type shown below. This time after unscrewing all detachable bits and then sawing the lens off the end, I got a roughly circular spread beam, part of the other end of the barrel is also sawn off so that I could attach a variable 3 volt d.c. power supply using croc clips. It is a good idea to hold the laser in a lab clamp and stand with only bare metal on the clamps jaws (not cork or rubber) so that it will help conduct the heat away and reach an equilibrium temperature for stability. Green lasers in the photo seem to operate with a current around 0.6 amp. But if they get too hot the light output can suddenly drop very low. The original battery supplied was listed as 3.7 volts and so this value must not be exceeded and it is best to work below this voltage level. If a holographic image shows a weird stripey image, that means the laser was operating in an unfavourable mode. [[File:JBWG.jpg|400px]] Slightly changing the voltage can often make the mode O.K. but I am afraid one can be unlucky with these very cheap lasers. I am very pleased with the luck I have had so far with such cheap laser power. With the cheapest narrower pen-like green laser-pointers, operating with two AAA batteries I found I could only get a hologram depth of little more than 1 cm, but this was still enough for making gelatin holograms of coins or of slightly angled flat mirrors to make useful sensors for moisture[ii] or protease enzymes[iii]. However, for serious holographic imaging one must spend more serious money getting a laser with a guarantee that it will operate in what is known as TEM00 mode and a coherence length of over 20 cm. [i] Blyth J. et alia The Imaging Science Journal Vol 47. 87-91 (1999) [ii] Holographic Sensor for Water in Solvents Jeff Blyth · Roger B. Millington · Andrew G. Mayes · Emma R. Frears · Christopher R. Lowe Apr 1996 · Analytical Chemistry vol 68, 1089-1094 [iii] A Holographic Sensor for Proteases Roger B. Millington · Andrew G. Mayes · Jeff. Blyth · Christopher R. Lowe Dec 1995 · Analytical Chemistry vol 67 4229-4233 cb5a41e5b28c60099d24e1efe1af728a44460ca4 6 1296 2735 2016-05-01T01:03:58Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1297 2736 2016-05-01T01:05:49Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1298 2737 2016-05-01T01:07:37Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1299 2738 2016-05-01T01:09:55Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1300 2739 2016-05-01T01:12:18Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1301 2741 2016-05-01T01:15:22Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1302 2742 2016-05-01T01:15:23Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 6 1303 2743 2016-05-01T01:15:24Z Jsfisher 1 MsUpload wikitext text/x-wiki MsUpload 519c08da88276b2f47bc6fb30637d415fd0d804e 0 945 2749 2198 2016-05-27T19:11:49Z Jsfisher 1 wikitext text/x-wiki Danny Bruza [http://www.holographyforum.org/forum/viewtopic.php?f=41&t=4078] was kind enough to share this chart he had made for his own use. The chart gives the playback Danny gets for a sequence of dichromate-to-gelatin concentrations at each of three recording wavelengths, 532nm, 514nm, and 405nm. {| class="wikitable" border="1" |- ! Di-gel ! 532nm ! 514nm ! 405nm |- | 10-30 || 532 || 514 || 405 |- | 09-30 || 552 || 533 || 424 |- | 08-30 || 571 || 552 || 443 |- | 07-30 || 590 || 571 || 462 |- | 06-30 || 609 || 590 || 481 |- | 05-30 || 628 || 609 || 500 |- | 04-30 || 647 || 628 || 519 |- | 03-30 || 666 || 647 || 538 |- | 02-30 || 685 || 666 || 557 |- | 01-30 || 704 || 685 || 576 |} Results can vary. Many, many factors come into play with dichromated gelatin. Gelatin bloom strength, humidity, temperature, exposure, and karma all have an effect. Nonetheless, the table provides some guidance. As another general guideline, bandwidth is affected by water concentration. Narrow band results are produced in the 150-250 range (meaning a 10-30-200 DCG formula, for example), and broader-band playback from the 300-350 range. c59f1ec04dc2e29d5e6e848b24a4e661a6768c38 0 866 2751 2620 2016-07-07T23:48:44Z Jsfisher 1 /* Albumen Emulsion Plates */ wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Albumen Emulsion Plates == Filipe Alves has a go at making albumen emulsion plates. See http://www.holographyforum.org/forum/viewtopic.php?t=831 Click on the '''play button''' to start the video: <html5media height="360" width="640">File:Holograms made with albumen emulsion.mp4</html5media> == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in three Holoforum threads: http://holoforum.org/forum/viewtopic.php?f=7&t=440 , http://holoforum.org/forum/viewtopic.php?f=7&t=497 , http://holoforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-[[Bloom value|bloom]] pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} a8db11479cad723d761e135345a72aeee4306c06 2754 2751 2016-10-05T20:07:43Z Jsfisher 1 /* Ferric Ammonium Oxalate */ wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Albumen Emulsion Plates == Filipe Alves has a go at making albumen emulsion plates. See http://www.holographyforum.org/forum/viewtopic.php?t=831 Click on the '''play button''' to start the video: <html5media height="360" width="640">File:Holograms made with albumen emulsion.mp4</html5media> == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in three Holoforum threads: http://holographyforum.org/forum/viewtopic.php?f=7&t=440 , http://holographyforum.org/forum/viewtopic.php?f=7&t=497 , http://holographyforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-[[Bloom value|bloom]] pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} a54247c8e0e3d4277604479c668f9466380e676e 2767 2754 2018-07-14T03:00:45Z Jsfisher 1 /* Albumen Emulsion Plates */ wikitext text/x-wiki [[http://en.wikipedia.org/wiki/Holography#Hobbyist_use From Wikipedia:]] Since the beginning of holography, experimenters have explored its uses. Starting in 1971, Lloyd Cross started the San Francisco School of Holography and started to teach amateurs the methods of making holograms with inexpensive equipment. This method relied on the use of a large table of deep sand to hold the optics rigid and damp vibrations that would destroy the image. Many of these holographers would go on to produce art holograms. In 1983, Fred Unterseher published the Holography Handbook, a remarkably easy-to-read description of making holograms at home. This brought in a new wave of holographers and gave simple methods to use the then-available AGFA silver halide recording materials. In 2000, Frank DeFreitas published the Shoebox Holography Book and introduced the use of inexpensive laser pointers to countless hobbyists. This was a very important development for amateurs, as the cost for a 5 mW laser dropped from $1200 to $5 as semiconductor laser diodes reached mass market. Now, there are hundreds to thousands of amateur holographers worldwide. In 2006, a large number of surplus Holography Quality Green Lasers (Coherent C315) became available and put Dichromated Gelatin (DCG) within the reach of the amateur holographer. The holography community was surprised at the amazing sensitivity of DCG to green light. It had been assumed that the sensitivity would be non-existent. Jeff Blyth responded with the G307 formulation of DCG to increase the speed and sensitivity to these new lasers. Many film suppliers have come and gone from the silver-halide market. While more film manufactures have filled in the voids, many amateurs are now making their own film. The favorite formulations are Dichromated Gelatin, Methylene Blue Sensitised Dichromated Gelatin and Diffusion Method Silver Halide preparations. Jeff Blyth has published very accurate methods for making film in a small lab or garage. A small group of amateurs are even constructing their own pulsed lasers to make holograms of moving objects. Holography kits with self-developing film plates have now entered the consumer market. The kits make holographs and have been found to be fairly error tolerant,and enable holograms to be made without any other specialized equipment. == Albumen Emulsion Plates == Filipe Alves has a go at making albumen emulsion plates. See http://www.holographyforum.org/forum/viewtopic.php?t=831 Click on the '''play button''' to start the video: [[File:Holograms made with albumen emulsion.mp4]] == Home-made Holographic Stereograms == A ''stereogram'' is an image that is able to convey a sense of depth to the viewer. Usually, two photographs of the same subject taken from two slightly different positions are used. A special viewer is used to present one photograph to the left eye and the other to the right to create the stereoscopic effect. Holography makes it possible to record a sequence of two or more photographs on a single hologram; the hologram requires no special viewer. The method presented here is by Holography Forum member, lobaz, in the thread http://holoforum.org/forum/viewtopic.php?f=11&t=718 ===Taking the pictures=== Point your camera to the subject, take picture 1. Move camera to the left/right, shoot another. ''Do not rotate the camera!'' It is much easier go get good results from a set of pictures with optical axes parallel to each other. The reason is simple: if you slightly rotate the camera so that it points to the subject, the background changes a lot. In stereograms, you need to keep disparity in some reasonable range, and keeping optical axes parallel helps to achieve it. Some people would argue that you are loosing resolution using this setup because the subject has to cover just a small part of the image. That's true. But you don't have to worry with many aspects of the crossed axes setup, this parallel setup just works. And with contemporary high resolution cameras there is room to sacrifice some pixels. How much to move the camera? It depends. If you want to display the subject in 1:1 scale, then about 60 mm (inter-ocular distance) is OK. I also assume the camera is in the same distance from the subject as the viewer, i.e. not too far and not too close. If you want to make e.g. macro photographs of a LEGO model of the house and want it to look like a real house, then the camera movement should be just several millimeters (i.e. the inter-ocular distance of a LEGO man). And so on. ===Editing the pictures=== Let us assume for simplicity you took just left and right pictures. If you display them simultaneously with e.g. anaglyph method, then points with zero disparity will lie in the plane of the display. Normally, with parallel axes setup, those would be points in the background. Everything else will be in front of the display plane. That's not very good. When you look at a stereoscopic point near an edge of the picture, there is a psychological conflict. Your eye axes try to cross somewhere in front of the display plane, but due to the proximity of the edge your eyes want also to focus and cross there. This problem is very serious if the stereoscopic point is in front of the display, not very serious if it is behind the display plane, and nonexistent if there is no content near the edges. So, what to do? Pick some point you would like to lie in the display plane. If you are shooting a portrait, then it is the best to pick the eye. Then most of the head will be behind the display plane and the nose will slightly go in front of it. So, load the pictures into different layers of a picture editor (e.g. PAINT.NET or Photoshop), make the layers semitransparent and move them so that the eyes are at the same location of the screen. Crop the picture so that every layer is fully covered by the particular image, make the layers opaque and print them. It is also important to choose the right size of the picture. As the printed pictures get bigger, then disparity also gets bigger and 3D effect is enhanced. If you want to control 3D effect precisely, then you have to take this into account when choosing inter-camera distance when shooting! I also recommend to do check your photographs with anaglyph. While in the editor, take the red channel from the left picture, the green and the blue channels from the right picture, and make a composite image. Put your anaglyph glasses on (red filter - left eye, cyan filter - right eye), display the picture in intended print size and check the 3D effect. ===Making H1=== I will describe the procedure for rainbow holograms but other hologram types are similar. Cut a strip of a holographic plate, put it into a holder. Make a screen that covers most of the strip except for the left part. Stick the "left" photograph to the picture holder and make a hologram. Then change the screen to the one that does not cover right part of the strip. Replace the photograph. Take care - left and right photographs have to be perfectly aligned! Do next holographic exposure. And so on, if you had just two photographs, you are done. If you had eight photographs, you have to imagine your H1 strip is split to eight parts, prepare eight screens that uncover just one part, and one by one carefully change the screens and the photographs. Very tedious! ===Making H2=== That's easy! Just make H2 the same way you would do common H2. For best results put your H2 plate to the same distance as was H1-photoholder distance. == Ferric Ammonium Oxalate == {| |- | [[File:FAO_TestGrating.JPG|400px|right]][[File:FAO_TestFigure.jpg|400px|right]] Ferric ammonium oxalate (FAO) and possibly ferric ammonium citrate (FAC) have possibilities as a substitute for ammonium or potassium dichromate in gelatin. Experimentation is chronicled in three Holoforum threads: http://holographyforum.org/forum/viewtopic.php?f=7&t=440 , http://holographyforum.org/forum/viewtopic.php?f=7&t=497 , http://holographyforum.org/oldforum/viewtopic.php?f=2&t=6553 . Test plates were fabricated using: * 30 g gelatin, 250-[[Bloom value|bloom]] pork * 6 g ferric ammonium oxalate * 300 ml water The coating thickness was estimated to be 7 to 9 microns. Plates were exposed three days after coating. Geometry was a two-beam transmission grating at zero degrees and 24 degrees (~900 l/mm) at 457 nm from a solid state Melles Griot laser. The pictured plate was a 60 mJ exposure (mJ/cm^2?). Processing was as follows: * 10 seconds in 1% Hydrogen Peroxide * 2 minutes water @ ~ 18 deg C * dehydration with IPA as per DCG processing The second picture is a single-beam reflection hologram take with a 25 minute exposure. |} ba1a37b4813d2309bc6739913d954ee14809bfb1 0 228 2752 1677 2016-07-13T13:44:02Z Jsfisher 1 wikitext text/x-wiki ==Some Uses for Everyday Items in Holography== by John Pecora Here are some tips for saving money on ‘lab’ equipment. It is surprising how many everyday objects can be used to good effect in holography. These are just suggestions. Please remember that it is your responsibility to pay attention to safety, and use common sense. *Heating pads used with three or more settings can be used as adjustable heaters for processing trays. Simply put the heating pad under the tray and turn the pad on to the desired setting. *Black foam board can be used for blocking stray light. The type that is black throughout is best as the edges stay black even when they are cut. This material can also be used for making an iris. *A shutter can be made from most old 8mmmovie cameras. They have a low voltage electric shutter. Remove this unit and set up a circuit with the original voltage of the camera, and a switch. *A thick piece of glass, 1/4 inch or thicker, can be used as a beam splitter. Using the thick piece of glass allows a small piece of electric tape to be placed over the glass to block the secondary reflection off the back. *Sandwich boxes can be use as processing trays and also as storage for the chemistry without having to pour the liquids back into bottles after each session. They come in many sizes and shapes with airtight lids. Store sealed containers with chemicals in a dark, dry, cool place when not being used. *Rubber inner tubes can be used as the dampening mechanism between a holographic table and the support legs. *A slab of granite can be used as a holographic table. *Most old overhead projectors contain large front surface mirrors and large Fresnel lenses. They can be purchased at yard sales and flea markets for just a few dollars. *Most photocopiers and fax machines contain front surface mirrors. *New Jefferson Nickels have a weight of 5 grams and new Lincoln Pennies have a weight of 2.5 grams. Standard paper clips have a weight of 1 gram. To verify the weight of the paper clips put a nickel on one side of the balance and find 5 paper clips of the same size that equals the nickel. These can be used on a balance for measuring out chemicals. *A hair dryer can be used to dry a piece of holographic film or plate after processing. Drying intensity and heat is variable with very inexpensive dryers. *Polarizers can be found in polarizing sun glasses. These can be used to adjust the intensity of polarized laser light by inserting the polarizer in the beam path and rotating. They can also be used to check the polarization of light at different locations in an optical set-up. *Two pieces of window pane glass and binder clips can be used to sandwich a piece of holographic film. This will hold the film rigid and flat. *A microwave can be used to warm the deionized or distilled water needed for mixing up processing chemistry. But please be careful to keep chemical-contaminated containers separate and secure. One method is to heat the water in a clean container in the microwave and then pour it into the chemical container for mixing, always keeping the clean container free of any chemicals. *Two-part, fast-hardening epoxy is great for securing two pieces of metal without the need for drilling and tapping. This also allows easy disassembly with just a small sharp blow to one of the pieces. *A pinhole can be made by sandwiching 5 or 10 pieces of aluminum foil together and poking with a pin while the pile is on a hard piece of rubber. Each piece of foil will have a slightly different size of pinhole. *Automobile windshield wiper blades can be used as a squeegee. If you epoxy two blades to a pair of scissors then, when the scissors are closed 3/4 of the way, you can squeegee both sides of the film at the same time. For plates this is not necessary as you can do one side at a time with a single blade. *Clothes pegs on a line can be used to hang up films to dry. After clamping the film at two corners with the pegs, clamp two more at the bottom corners as weights to keep the film straight while drying. *Dishwasher drying agent can be in place of PhotofloTM in the final rinsing bath. Use an agent that does not have fragrance and, preferably, one that is clear. *Sodium carbonate can be purchased cheaply as a chemical for increasing the pH of swimming pools and spas. *Sodium bisulfate can be purchased cheaply as a chemical for decreasing the pH of swimming pools and spas. *Sulfuric acid can be purchased as car battery acid. Most formulas call for concentrations that are lower than that sold as auto battery acid. *Black Sanford Sharpie markers, which come in different sizes, are ideal for blackening optics, mounts and anything small you want to reduce reflections on. They are permanent markers that write on almost anything. *Paper MateTM liquid paper correction is great for painting objects for holography. It dries to a flat white and diffuses the light very well. *A disposable shower curtian works well as a dust protector for a collimation mirror. c1f8b58fd7ebb5b2ae49091d07e1ba860336e54f 0 808 2753 2568 2016-09-23T01:04:11Z Jsfisher 1 /* Modern Beginner's Kit */ wikitext text/x-wiki {{#seo:|description=How to get started making your own holograms}} [[Image:Sandbox_Kit.jpg|right]]The "original" hobbyist's approach to holography was described in the May 1979 issue of ''Physics Education'' as the aptly named ''Sandbox Holography''. Metrologic produced and sold an identically named kit. The kit included some holographic film, chemicals for processing the film, and few lenses and mirrors. Not included were the laser (and at the time, that meant a moderately pricey helium-neon gas laser) nor the sandbox. Holography is extremely sensitive to movement, even microscopic movement, during the exposure. In conventional photography, movement will blur the image. With a hologram, since movement would completely alter the interference pattern between the direct and reflected laser light, the image can be lost completely. The sandbox was used to help eliminate vibration. In the late 1970's and early 1980's, the Metrologic Instruments Sandbox Holography kit might have cost you $150(US). A suitable laser, another $400 or so, and by the time you had the sandbox set up, you would be out $600 to $700 in 1980 dollars. For the curious, an updated version of the kit is still available from [http://i-fiberoptics.com/laser-kits-projects-detail.php?id=2140 Industrial Fiber Optics]. Industrial Fiber Optics purchased the educational laser and kit product line from Metrologic Instruments in November 2004. Although the [http://i-fiberoptics.com/pdf/45-733a_manual-revc.pdf Sandbox Holography] manual has details specific to the sandbox kit, it still provides a general introduction to holography for the beginner. == Modern Beginner's Kit == [[Image:Integraf_kit.jpg|right]]Diode lasers, like the ones found in common laser pointers, have completely changed what is needed for a suitable beginner's kit. You still need film and processing chemicals, but your first hologram can be made with no additional lenses or mirrors (because the diode laser beam naturally spreads), and there are some simple techniques developed over the years since the Sandbox kit was first introduced to eliminate the sandbox. In the new era, sandbox holography has evolved into [https://books.google.com/books/about/Shoebox_holography.html?id=BShRAAAAMAAJ Shoebox Holography], and there are now three, relatively economic ways for novice holographers to begin their hobby. #Buy the ''Shoebox Holography'' book. With that as a guide (or the equivalent information scoured from the Internet) acquire a suitable laser, holographic film, and chemicals and have at it. #Acquire one of the kits available from [http://www.integraf.com/holography_kit.htm Integraf]. (Film is more difficult to work with than glass plates, so the Standard or Student Kit is much preferred over the Budget Kit.) #Acquire a different type of kit from [http://www.litiholo.com Litiholo]. For the truly novice holographer, the Litiholo kit is a a bit of an oddity. With it, you can produce your first, interesting hologram. The kit comes with 20 plates, so there is plenty of opportunity for experimentation and the inevitable failure. Be aware, though, it is a self-contained unit. The holographic plates are self-developing, and the configuration is limited to the setups the kit intended. For the mildly curious individual or the elementary school aged child, the Litiholo kit is fabulous. For the slightly experienced holographer, it is good, if for nothing else than the exposure to polymer photo-materials. For the true beginner, though, it is a little like buying a TV dinner because you wanted to learn to cook. There is not enough "participation" to engage the beginner. Of the remaining two choices, simply buying a kit from Integraf saves you all the hassle of acquiring the parts individually. Plus you end up with a higher quality laser than what you would get from an ordinary laser pointer. Some laser pointers have stability issues that may be unnoticeable in normal use, but disastrous in holography. The information that comes with the Integraf kit, or the identical [http://www.integraf.com/a-simple_holography.htm material available from the Integraf web site], or similar articles online, or from texts like the ''Shoebox Holography'' book, covers what to do next. Not much to it, really. == Beginner's FAQ == ; What is a hologram? : Most commonly, a hologram is a 3-D Picture. It looks like a window into the original scene from which it was created. [http://en.wikipedia.org/wiki/Hologram Wikipedia's entry on Hologram/Holography] ; How little money/bother do I need to make one? : You can make your first hologram with about 2 hours of set up and about $100. ; What is the cheapest way to make a hologram? : [[Laser Pointer Holography]] is the cheapest way to make a hologram. Also check out [http://www.holokits.com/holography_tutorials.htm Integraf's Instructions] for making a hologram. ; Are the chemicals dangerous? : While some of the processing chemicals can be dangerous, processing schemes are available, such as JD-3, that can be used in elementary schools. If you want more information on the hazards of a particular chemical you can easily find it by Googling "MSDS" and the name of the chemical. This will provide you avenues to download the Material Safety Data Sheet for that particular chemical. (ie. MSDS Metol) Bear in mind that many of these sheets make slightly hazardous chemicals sound much more frightening than they really are. For practical recommendations on holographic chemical usage there's no substitute for asking on the Holography Forum. ; What sort of time commitment is there for making a hologram? : You can make a hologram in about 2 hours the first time. Once you have some experience you can set up, expose and develop in under an hour. ; When can I have the lights 'on' during the procedure of making a hologram? : Once the emulsion has become insensitive to to light. For silver-halide holograms this is after the hologram is bleached. For dichromated gelatin holograms this is after the fixing and rinsing steps. ; What are the different kinds of holograms? : [[Different kinds of holograms|Click here - for the differences in the kinds of holograms]] ; What is the single most important factor when making a hologram? : ''Stability!'' For simple holograms the required stability can be achieved by making sure that the plate and object touch and that there is no motion or vibration in the room during the exposure. For more complex set-ups involving a beamsplitter, all of the components after the beamsplitter need to be stable to within 1/4 of a fringe. Since fringe spacings range from about 600 to 2000 lines per mm the stability requirements can be quite high and involve building a Vibration Isolation Table/Bench. Pulse holography negates the need for stability but a suitable laser is expensive and dangerous to set up. ; How Does a LASER work? : For a simple introduction to lasers read [[How Do LASERs work?]]. ; Can I use a cheap red laser pointer to make holograms? : Yes! Almost any of them will work to some degree. If you take the beam and spread it through a lens (or remove the built-in collimating lens to produce a spread beam) and the illumination looks uniform and does not have black lines in it you can probably use it to make a hologram. The Infiniter 200 is a common choice because many have had success with it. The batteries in a red laser pointer don't last very long. It is quite common for holographers to cut the barrel off the pointer and wire up D-cell batteries in order for the laser to remain at full power longer. ; Can I use a Green Laser Pointer to make holograms? : So far they seem to be unusable. And, some can be damaged if left on too long. But, by all means give it a try. Red pointers were thought unstable for some time but everyone was proved wrong. ; Where are the Reference and Object beams in a Single Beam Reflection Hologram? : Single Beam Reflection (SBR) holograms are actually made with two beams. In a SBR Hologram the light travels to the film and we will call this light B1B2. Some of this light travels through the film. This is just the B2 part of the B1B2 light. It illuminates and reflects off the object back to the film. This is the object beam. This B2 light interferes with the B1 part of the original B1B2 within the film thickness. This creates a standing wave pattern thus the fringes or hologram. So there really are actually two beams used to create the hologram in a Single Beam Hologram. ; Some uses for [[Everyday Items]] in holography : Click here for [[Everyday Items]] that can save you money in holography! ; What is a [[Scratch-O-Gram]]? : A [[Scratch-O-Gram]] is a hand drawn hologram. It works by reflecting light and focusing it from a curved scratch to a point. ; What Books are Available for Holography? : See the [[Books]] section. [[Category:Beginner]] c4e3308d57b594baae19fb2c302420e9e9013591 0 432 2755 1755 2016-10-25T16:47:51Z Jsfisher 1 wikitext text/x-wiki [http://www.mbenyon.com Margaret Benyon's Website] [[Image:Mbenyon.gif]] Initially a painter, Margaret Benyon began to make holograms in 1968 when holography was available only to scientists. Her aim was to take holography out of the science lab, and to enlarge the boundaries of what was traditionally seen as fine art. Her early body of work with holography was an exploration of those aspects that were unique to it. Living in Australia with her partner and two small children in the 1970's led to work that was more humanist and cross-cultural. On returning to the UK in 1980 she began to use the human body exclusively, in a personal, partly therapeutic way. More recently she has been exploring the naturalisation of holography, and the female aesthetic. Her work with creative holography has been recognised with academic fellowships, artists' residencies, and a number of other art and holography related awards. She is currently listed in the International Who's Who, and in the millenium year she was awarded an MBE by HM the Queen in the New Year Honours List 2000 for services to art. Her work has been seen in a large number of exhibitions, in countries as far apart as the USA, Canada, Portugal, Italy, Australia, France, Germany, Japan, and China. Her works are in a number of public collections, including the Australian National Gallery and the Victoria and Albert Museum, London, and in an undocumented number of private collections world-wide. In 1994 she received a Ph.D. from the Royal College of Art, London, for her research and activities in art holography. Margaret Benyon made most of her holograms in her home studio on the south coast of England for 23 years. This was a basic, low-tech, non-commercial holographic studio, one of very few in existence. However, she also used more sophisticated international labs, and in 2005 moved to Sydney, Australia. She became an honorary Professorial Visiting Fellow at the College of Fine Art at the University of New South Wales, and continued to work internationally from Australia. Her health eventually decline in her latter years. She passed away October 21, 2016 at age 76. af328cc75edd68bf4987f986457f6cff4df71fa6 0 207 2769 1637 2018-11-18T02:07:03Z Jsfisher 1 wikitext text/x-wiki Jeff Blyth has online instructions for making Silver Halide Plates. *http://d-i-yscience.blogspot.co.uk/2016/04/holograms-on-wine-glasses-and-glass.html Jeff Blyth's recipe for making your own silver plates] ===Gelatin Film thickness=== In the case of MBDCG a thinner film can give a bit more sensitivity because you can have more MB dye in. If x % of dye is optimum for a dried film of 10 microns then for a dried film of say 40 microns you need to cut it down to 0.25x% and that is usually bad for sensitivity. If you leave it at x% then you kill too much object beam light. However you can get away with x% if you are able to do split beam reflection work (unlikely you have enough laser power with MBDCG unless you are making say 1 sq cm size images). Single beam transmission H’s could be OK though. ===Silver Halide=== If the diffusion method is tried on coatings much thicker than 7 microns it is troublesome. I have tried it on ~ 100 micron gelatin and decided that it was not viable. The problem being that the rate of diffusion decreases exponentially with time and AgNO3 can carry on diffusing into the thick film and away from the incoming bromide ions . If you leave it long enough (several minutes) for the bromide ions to catch up and combine with the furthest Ag ions near the glass then the front end may have already been in the Br bath too long and you start to get grain growth . If you don’t catch those unreacted Ag ions at the glass end then they quite rapidly develop up in the (ascorbic acid pH 6) sensitizer bath causing bad darkening or bad fog. You can stop this by giving the film a very prolonged soak in tap water (with its Cl- ions) after the Br bath before the sensitizer bath. What you get is then virtually all the silver bromide in the first few microns and none in the gelatin nearer to the glass , you might just as well have coated it thinner in the first place. However using the conventional process with AgBr precipitated in molten gelatin solution you still get fundamental problems if you try to coat ultra thick layers. The processing chemicals take much longer to migrate in and grain growth and unevenness is inevitable. I needed to make some experimental coatings about 1 mm thick and although I got gratings they were sadly dim. I struggled to get any grating at all. Once upon a time, Agfa produced an experimental 8E75’B’ coating that was twice as thick as usual but still only ~ 15 microns . Nobody found they could get a good result from it compared to their standard 7 micron. Jeff ===Hans' Diffusion Post=== As promised, here is a revision of Jeff Blyth's diffusion method that will allow you to make very bright holograms, and some theory as to why I think it works so well. When making your own holographic plates there are two requirements for bright results that work against one another: Lots of AgBr should be in the emulsion, and the AgBr crystals (grains) that are made up from all this AgBr should be as small as possible. It normally is very difficult to make an emulsion that complies to both these requirements and lots of articles have been written up about solving this problem. Lots of methods have been invented, but few are as reliable as Jeff's diffusion method. Why is it so difficult to make small grains: Imagine you have a gelatin solution into which you want to introduce AgBr grains. The traditional method would be to add to this gelatin solution a solution of AgNO3 and a solution of KBr. Both would be added at the same time at a certain rate. This method is called the double jet method. When the addition of the two solutions is started, at first nothing happens. Only the concentrations of both solutions slowly increase in the gelatin solution. Above a certain concentration, suddenly lots of Ag+ ions combine with lots of Br- ions to form very minute AgBr crystals. The formation of these crystals causes a fast decrease in concentration of both the AgNO3 and the KBr. As soon as the concentration drops below a certain value, any added AgNO3 + KBr will not create new grains (as we would like), but cause the grains that are already there to grow. This growing of the grains is not desirable. So, what I mean to say is that for new grains to form, the concentrations of the AgNO3 + KBr need to be above a certain critical value. Concentrations below this value cause grain growth and even lower concentrations do nothing at all. As you can see now the double jet method needs precisely controlled flows of liquids to allow for concentrations to be above this critical nucleation concentration to allow as many micrograins to form. Second problem is that if there are many small grains present, any newly added AgNO3+KBr prefers to settle onto those grains rather than forming new nuclei. And here lies the difficulty in making emulsions with both small grains and lots of grains at the same time. Most of the old recipes for making Lippmann emulsions are for making very fine grain emulsions, but with a very low amount of silver in them. Manufacturers of holographic film usually keep their methods for making their emulsions a secret just because of this reason. Now if there were a method of instant mixing a gelatin emulsion of very high concentration AgNO3 with a liquid of very high concentration of KBr (and very quickly after mixing both the excess AgNO3 and KBr could be removed), very small grains in high quantity would be virtually guaranteed. And this is where Jeff's brilliant diffusion strategy comes to the rescue: Imagine you had a very thin gelatin layer that was soaked with AgNO3 and this would be suddenly dunked into a solution of KBr, the KBr would be introduced to the AgNO3 throughout the surface of the gelatin as it diffuses into the layer. So a great many small grains of AgBr would form instantly everywhere inside the very thin layer of gelatin. If the layer is then quickly washed after this step, all excess AgNO3 and KBr are removed and thus further growing of the grains is no longer possible. This is not the whole story by a long shot though. In normal kitchen gelatin there are often left-over chemicals from the fabrication process that actually encourage grain growth. Any chlorides present in the gelatin would hamper the formation of small grains because AgCl is a lot more soluble than AgBr and also because when the AgNO3 is added to the gelatin, the first nuclei that are formed are AgCl nuclei and that's not what we want because we want the sudden process of virgin AgBr nucleation as the gelatin is dunked into the KBr solution. Any chemicals with Sulfides in them also cause grain growth. Luckily there is a way to clean your gelatin. More about this later. Just like there are chemicals that encourage grain growth, there are also chemicals that discourage grain growth. And that is where the second brilliant idea of Jeff comes to play. It just so happens that the dye used in the diffusion process (pinacyanol chloride) is one of those chemicals that help prevent grain growth. Adding this dye (that makes your emulsion sensitive to red laser light) to the KBr solution will help keep the grains small: as the gelatin is dunked into the KBr, the newly formed grains are quickly coated with dye molecules, preventing further settling of new AgBr onto them. One problem with the dye is that it does not like to be in water. That is why the KBr mixture is actually a mixture of water+methanol. The dye is very soluble of methanol and will stay even in solution if some water is present. Ok, so much for theory. Here is the procedure. Rather than writing up the differences from Jeff's original procedure I will now proceed and type the whole recipe. ====Washing the gelatin==== For this you need a small glass jar. Fill jar with 20ml of de-ionized (DI) water and add about 2.2 gram of gelatin. Next slowly warm this mixture to about 45C until the gelatin is completely dissolved. Take a plastic tupperware and pour this liquid into it and allow it to gel. When the solution has gelled, cut this gel up into small cubes with a plastic knife. Pour about 100ml of cold DI water into the tupperware tray, rock it a little and let it sit for about 30 minutes. (this step allows any contaminants in the gelatin to diffuse into the DI water). Pour off the DI water and add fresh DI water, rock and let it stand 30 minutes again. Repeat this procedure about 4 times. When you're done washing the gelatin, put it back into the glass jar and put it in the fridge (not the freezer) for later use. ====Preparing the glass==== When put into a alkaline developer, gelatin does not want to stick to glass anymore. So the glass needs to be prepared for holographic use. Firstly wash a piece of glass (say 20x30cm) with vinegar (this will remove some of the grease that is on the glass). After that, vigorously rub the glass with household ammonia and be very careful not to get any of this into your eye because it will make you blind forever. Now the glass will be very clean. The next step will be to chemically treat the glass to make it sticky. ====Making the glass sticky for gelatin==== Add about 0.5ml of 3-amino-propyltriethoxysilane (less is better than more) to 100ml of Acetone and rub this solution onto your cleaned glass plate. Let the plate sit for about one hour and then clean it again. This time with a Ammonia based glass cleaner. Your glass has now been coated with a very thin layer of molecules that on one side stick to the glass. The exposed sides of these silane molecules have -NH3+ endings that bond well with the gelatin. ====RainX==== You will need a second glass plate to be able to make a nice gelatin coating. Throughly clean a glass plate of the same size as the plate that was prepared from step [2] and rub it with an automotive anti rain agent such as Rain-X. And then rub it with a clean dry towel. On two opposing edges of this plate stick a long piece of Scotch tape. (During the coating step, gelatin will be poured onto this plate and the silane treated plate will be put on top of this gelatin puddle. The Scotch tape acts as a spacer and allows a perfect gelatin coating with just the right thickness when dried.) ====Preparing the chemicals==== * Mix 1g of pinacyanol chloride in 1000ml of methanol. This solution will last you a life time. * Mix 33ml of water with 66ml of Methanol. To this solution add 6 gram of LiBr and 2.5ml of the dye solution. Pour this liquid into a Tupperware tray that is big enough to hold your glass plate and close it. ====Wear Safety Glasses==== If you get AgNO3 in your eye you will be blind forever.:Take your washed gelatin from the fridge and warm it up to 45C again. When it has become completely liquid again, add 1.2 gram of AgNO3 to this solution. Often the solution becomes milky when you do this, but if you stir for about a minute, it will become transparent again. ====Coating the Plate==== Heat your Silane treated glass plate with a hair drier and while holding it level (USE KITCHEN GLOVES), pour a puddle of your gelatin on top of it. Quickly place the Rain-X treated glass plate on top of it and allow the gelatin to completely spread between the glass plates. After a few minutes the gelatin will gel and both plates will stick together. Now place this sandwich into the fridge and leave it there for a few hours. ====Washing Baths==== When doing the diffusion method it is important to stop the grain growth as soon as the grains are formed. Also it is preferable to remove any excess silver nitrate from the coating as soon as possible. So, prepare two trays of DI water to remove most of the AgNO3 and LiBr that is left over in the gelatin and one tray with tap water (most tap water contains some chloride that will precipitate with whatever Ag+ ions that are left after washing). To the tap water bath you should add a few drops of liquid dishwasher fluid. ====Diffusion Step==== After a few hours remove your glass sandwich from the fridge into your safe lighted room. With a plastic knife remove the Rain-X treated plate from your Silane treated plate. If all went well, the gelatin coating should stick to the Silane treated plate in a perfect smooth coating. Without waiting for the plate to dry or become warm, immediately drop this plate into the LiBr bath and leave it there for about 45 seconds. Then quickly take the plate out and transfer it to the first DI water bath for about 1 minute. Then the second DI water bath, then the tap water bath. Let the plate drip dry by setting it almost vertically against an object on your table. After about 15 minutes when most of the water has dripped from the plate you can use a cool hair drier to finish drying. ====Sensitizing==== Your freshly made plate will not be sensitive enough yet for practical use. Also the gamma of the emulsion will not be suitable yet for holography. Prepare a solution of 100ml water + 1.2 grams of Ascorbic Acid (=vitamin C) + 0.4 gram of NaCO3 + few drops of dishwasher liquid. Immerse your plate into this for about 2 minutes and dry again. When the plate is dry, it is ready for use and to be exposed for the brightest Denisyuk hologram you have ever made. Ok, so that's about it. It looks like a complicated and long procedure. But after you have done it a few times, you will find it easy and simple to do and reasonably fast. It is possible to make a number of plates in one day and store them in the fridge for later use. This procedure addresses a number of problems in the original procedure: * Lots more silver will be present in the gelatin. This will make your holograms a lot brighter. The original recipe calls for first coating the gelatin and afterwards introducing the AgNO3. This can certainly be done, but the gelatin needs to be very very hard and squeegeed well after adding the AgNO3. Otherwise AgNO3 will crystallize on the surface of the gelatin layer and prevent diffusion from taking place. * This method will allow for very soft gelatin layers to be made. This is interesting if you want to experiment in doing SHSG. * In the original method there is also some Ascorbic Acid in the LiBr+dye bath. This certainly does work, but you run the risk of developing out any AgNO3 that has not precipitated out. This causes some darkening of the plate. It is better to do the sensitizing afterwards. ====A SHORTCUT THAT IS ADVISABLE FOR FIRST TESTS==== * This adjustment will allow you to do the diffusion method very fast and still give the same brightness. * Skip steps [1] through [7] * Immerse a PFG-01 plate in a solution of 20% Sodium Thiosulfate (non hardening fixer) until it has become completely transparent. And rinse in DI water and dry. * Prepare a solution of 1 ml DI water + 0.18g AgNO3. * With a laser printer transparency spread a few drops of this solution over the surface of the fixed out plate and squeegie the plate very well. * Start from step 8 in the above procedure. * You have now upgraded your PFG-01 plate to a plate that competes well with the brightest plates in the world. I have done the original method, my adjusted method and the quicker method many times over and they give predictable results but have now switched to a completely different method (using double jet) that I don't want to write about just yet. ====INTERESTING EXPERIMENTS TO TRY==== *Gelatin at low concentration is much easier to coat than the 10% that is required for the above procedure. It would be interesting to try to make your fresh dry gelatin into a very fine powder in a kitchen slurpy mixer. Then load this fine powder in a very cold solution of AgNO3. The solution needs to be cold because otherwise the powder will become a sticky mass. Next run this mix through a coffee filter to drain off excess water+AgNO3. Then pour your LiBr+dye mixture over the powder that is still in the coffee filter (do catch what drips out of the filter because it can be used again). Next pour large amounts of DI water through the filter. If all liquids are rather cold during this procedure the gelatin will not clump up and it just might work. After this procedure you would have holographic gelatin that can dissolved when needed at concentrations of about 2% and coated by just pouring on a horizontal glass plate. I don't know if this procedure would work. But if it does work it would be very nice. I tried it once but made a mistake in the dark and made a mess of it. So I was not able to conclude if it is possible or not. *To coat a layer of 2% gelatin on glass to which some dichromate is added. Then make this layer really hard in an oven and use the shortcut method I wrote about above. The layer should be very smooth and hard enough to allow a good squeegee. I have not tried this, but if it works it will be a lot faster. Well, that's about all I know about the diffusion method. I very much enjoyed using it. Please understand that this is by no means the only way to do the diffusion method. If you want to have a go at it, try it this way first and then experiment with your own idea's. I am sure you will come up with idea's that will improve upon this method. 3d872ebdbeb95f999e59816f422f4a8b5a34eeb7 2770 2769 2018-11-18T02:07:45Z Jsfisher 1 wikitext text/x-wiki Jeff Blyth has online instructions for making Silver Halide Plates. *[http://d-i-yscience.blogspot.co.uk/2016/04/holograms-on-wine-glasses-and-glass.html Jeff Blyth's recipe for making your own silver plates] ===Gelatin Film thickness=== In the case of MBDCG a thinner film can give a bit more sensitivity because you can have more MB dye in. If x % of dye is optimum for a dried film of 10 microns then for a dried film of say 40 microns you need to cut it down to 0.25x% and that is usually bad for sensitivity. If you leave it at x% then you kill too much object beam light. However you can get away with x% if you are able to do split beam reflection work (unlikely you have enough laser power with MBDCG unless you are making say 1 sq cm size images). Single beam transmission H’s could be OK though. ===Silver Halide=== If the diffusion method is tried on coatings much thicker than 7 microns it is troublesome. I have tried it on ~ 100 micron gelatin and decided that it was not viable. The problem being that the rate of diffusion decreases exponentially with time and AgNO3 can carry on diffusing into the thick film and away from the incoming bromide ions . If you leave it long enough (several minutes) for the bromide ions to catch up and combine with the furthest Ag ions near the glass then the front end may have already been in the Br bath too long and you start to get grain growth . If you don’t catch those unreacted Ag ions at the glass end then they quite rapidly develop up in the (ascorbic acid pH 6) sensitizer bath causing bad darkening or bad fog. You can stop this by giving the film a very prolonged soak in tap water (with its Cl- ions) after the Br bath before the sensitizer bath. What you get is then virtually all the silver bromide in the first few microns and none in the gelatin nearer to the glass , you might just as well have coated it thinner in the first place. However using the conventional process with AgBr precipitated in molten gelatin solution you still get fundamental problems if you try to coat ultra thick layers. The processing chemicals take much longer to migrate in and grain growth and unevenness is inevitable. I needed to make some experimental coatings about 1 mm thick and although I got gratings they were sadly dim. I struggled to get any grating at all. Once upon a time, Agfa produced an experimental 8E75’B’ coating that was twice as thick as usual but still only ~ 15 microns . Nobody found they could get a good result from it compared to their standard 7 micron. Jeff ===Hans' Diffusion Post=== As promised, here is a revision of Jeff Blyth's diffusion method that will allow you to make very bright holograms, and some theory as to why I think it works so well. When making your own holographic plates there are two requirements for bright results that work against one another: Lots of AgBr should be in the emulsion, and the AgBr crystals (grains) that are made up from all this AgBr should be as small as possible. It normally is very difficult to make an emulsion that complies to both these requirements and lots of articles have been written up about solving this problem. Lots of methods have been invented, but few are as reliable as Jeff's diffusion method. Why is it so difficult to make small grains: Imagine you have a gelatin solution into which you want to introduce AgBr grains. The traditional method would be to add to this gelatin solution a solution of AgNO3 and a solution of KBr. Both would be added at the same time at a certain rate. This method is called the double jet method. When the addition of the two solutions is started, at first nothing happens. Only the concentrations of both solutions slowly increase in the gelatin solution. Above a certain concentration, suddenly lots of Ag+ ions combine with lots of Br- ions to form very minute AgBr crystals. The formation of these crystals causes a fast decrease in concentration of both the AgNO3 and the KBr. As soon as the concentration drops below a certain value, any added AgNO3 + KBr will not create new grains (as we would like), but cause the grains that are already there to grow. This growing of the grains is not desirable. So, what I mean to say is that for new grains to form, the concentrations of the AgNO3 + KBr need to be above a certain critical value. Concentrations below this value cause grain growth and even lower concentrations do nothing at all. As you can see now the double jet method needs precisely controlled flows of liquids to allow for concentrations to be above this critical nucleation concentration to allow as many micrograins to form. Second problem is that if there are many small grains present, any newly added AgNO3+KBr prefers to settle onto those grains rather than forming new nuclei. And here lies the difficulty in making emulsions with both small grains and lots of grains at the same time. Most of the old recipes for making Lippmann emulsions are for making very fine grain emulsions, but with a very low amount of silver in them. Manufacturers of holographic film usually keep their methods for making their emulsions a secret just because of this reason. Now if there were a method of instant mixing a gelatin emulsion of very high concentration AgNO3 with a liquid of very high concentration of KBr (and very quickly after mixing both the excess AgNO3 and KBr could be removed), very small grains in high quantity would be virtually guaranteed. And this is where Jeff's brilliant diffusion strategy comes to the rescue: Imagine you had a very thin gelatin layer that was soaked with AgNO3 and this would be suddenly dunked into a solution of KBr, the KBr would be introduced to the AgNO3 throughout the surface of the gelatin as it diffuses into the layer. So a great many small grains of AgBr would form instantly everywhere inside the very thin layer of gelatin. If the layer is then quickly washed after this step, all excess AgNO3 and KBr are removed and thus further growing of the grains is no longer possible. This is not the whole story by a long shot though. In normal kitchen gelatin there are often left-over chemicals from the fabrication process that actually encourage grain growth. Any chlorides present in the gelatin would hamper the formation of small grains because AgCl is a lot more soluble than AgBr and also because when the AgNO3 is added to the gelatin, the first nuclei that are formed are AgCl nuclei and that's not what we want because we want the sudden process of virgin AgBr nucleation as the gelatin is dunked into the KBr solution. Any chemicals with Sulfides in them also cause grain growth. Luckily there is a way to clean your gelatin. More about this later. Just like there are chemicals that encourage grain growth, there are also chemicals that discourage grain growth. And that is where the second brilliant idea of Jeff comes to play. It just so happens that the dye used in the diffusion process (pinacyanol chloride) is one of those chemicals that help prevent grain growth. Adding this dye (that makes your emulsion sensitive to red laser light) to the KBr solution will help keep the grains small: as the gelatin is dunked into the KBr, the newly formed grains are quickly coated with dye molecules, preventing further settling of new AgBr onto them. One problem with the dye is that it does not like to be in water. That is why the KBr mixture is actually a mixture of water+methanol. The dye is very soluble of methanol and will stay even in solution if some water is present. Ok, so much for theory. Here is the procedure. Rather than writing up the differences from Jeff's original procedure I will now proceed and type the whole recipe. ====Washing the gelatin==== For this you need a small glass jar. Fill jar with 20ml of de-ionized (DI) water and add about 2.2 gram of gelatin. Next slowly warm this mixture to about 45C until the gelatin is completely dissolved. Take a plastic tupperware and pour this liquid into it and allow it to gel. When the solution has gelled, cut this gel up into small cubes with a plastic knife. Pour about 100ml of cold DI water into the tupperware tray, rock it a little and let it sit for about 30 minutes. (this step allows any contaminants in the gelatin to diffuse into the DI water). Pour off the DI water and add fresh DI water, rock and let it stand 30 minutes again. Repeat this procedure about 4 times. When you're done washing the gelatin, put it back into the glass jar and put it in the fridge (not the freezer) for later use. ====Preparing the glass==== When put into a alkaline developer, gelatin does not want to stick to glass anymore. So the glass needs to be prepared for holographic use. Firstly wash a piece of glass (say 20x30cm) with vinegar (this will remove some of the grease that is on the glass). After that, vigorously rub the glass with household ammonia and be very careful not to get any of this into your eye because it will make you blind forever. Now the glass will be very clean. The next step will be to chemically treat the glass to make it sticky. ====Making the glass sticky for gelatin==== Add about 0.5ml of 3-amino-propyltriethoxysilane (less is better than more) to 100ml of Acetone and rub this solution onto your cleaned glass plate. Let the plate sit for about one hour and then clean it again. This time with a Ammonia based glass cleaner. Your glass has now been coated with a very thin layer of molecules that on one side stick to the glass. The exposed sides of these silane molecules have -NH3+ endings that bond well with the gelatin. ====RainX==== You will need a second glass plate to be able to make a nice gelatin coating. Throughly clean a glass plate of the same size as the plate that was prepared from step [2] and rub it with an automotive anti rain agent such as Rain-X. And then rub it with a clean dry towel. On two opposing edges of this plate stick a long piece of Scotch tape. (During the coating step, gelatin will be poured onto this plate and the silane treated plate will be put on top of this gelatin puddle. The Scotch tape acts as a spacer and allows a perfect gelatin coating with just the right thickness when dried.) ====Preparing the chemicals==== * Mix 1g of pinacyanol chloride in 1000ml of methanol. This solution will last you a life time. * Mix 33ml of water with 66ml of Methanol. To this solution add 6 gram of LiBr and 2.5ml of the dye solution. Pour this liquid into a Tupperware tray that is big enough to hold your glass plate and close it. ====Wear Safety Glasses==== If you get AgNO3 in your eye you will be blind forever.:Take your washed gelatin from the fridge and warm it up to 45C again. When it has become completely liquid again, add 1.2 gram of AgNO3 to this solution. Often the solution becomes milky when you do this, but if you stir for about a minute, it will become transparent again. ====Coating the Plate==== Heat your Silane treated glass plate with a hair drier and while holding it level (USE KITCHEN GLOVES), pour a puddle of your gelatin on top of it. Quickly place the Rain-X treated glass plate on top of it and allow the gelatin to completely spread between the glass plates. After a few minutes the gelatin will gel and both plates will stick together. Now place this sandwich into the fridge and leave it there for a few hours. ====Washing Baths==== When doing the diffusion method it is important to stop the grain growth as soon as the grains are formed. Also it is preferable to remove any excess silver nitrate from the coating as soon as possible. So, prepare two trays of DI water to remove most of the AgNO3 and LiBr that is left over in the gelatin and one tray with tap water (most tap water contains some chloride that will precipitate with whatever Ag+ ions that are left after washing). To the tap water bath you should add a few drops of liquid dishwasher fluid. ====Diffusion Step==== After a few hours remove your glass sandwich from the fridge into your safe lighted room. With a plastic knife remove the Rain-X treated plate from your Silane treated plate. If all went well, the gelatin coating should stick to the Silane treated plate in a perfect smooth coating. Without waiting for the plate to dry or become warm, immediately drop this plate into the LiBr bath and leave it there for about 45 seconds. Then quickly take the plate out and transfer it to the first DI water bath for about 1 minute. Then the second DI water bath, then the tap water bath. Let the plate drip dry by setting it almost vertically against an object on your table. After about 15 minutes when most of the water has dripped from the plate you can use a cool hair drier to finish drying. ====Sensitizing==== Your freshly made plate will not be sensitive enough yet for practical use. Also the gamma of the emulsion will not be suitable yet for holography. Prepare a solution of 100ml water + 1.2 grams of Ascorbic Acid (=vitamin C) + 0.4 gram of NaCO3 + few drops of dishwasher liquid. Immerse your plate into this for about 2 minutes and dry again. When the plate is dry, it is ready for use and to be exposed for the brightest Denisyuk hologram you have ever made. Ok, so that's about it. It looks like a complicated and long procedure. But after you have done it a few times, you will find it easy and simple to do and reasonably fast. It is possible to make a number of plates in one day and store them in the fridge for later use. This procedure addresses a number of problems in the original procedure: * Lots more silver will be present in the gelatin. This will make your holograms a lot brighter. The original recipe calls for first coating the gelatin and afterwards introducing the AgNO3. This can certainly be done, but the gelatin needs to be very very hard and squeegeed well after adding the AgNO3. Otherwise AgNO3 will crystallize on the surface of the gelatin layer and prevent diffusion from taking place. * This method will allow for very soft gelatin layers to be made. This is interesting if you want to experiment in doing SHSG. * In the original method there is also some Ascorbic Acid in the LiBr+dye bath. This certainly does work, but you run the risk of developing out any AgNO3 that has not precipitated out. This causes some darkening of the plate. It is better to do the sensitizing afterwards. ====A SHORTCUT THAT IS ADVISABLE FOR FIRST TESTS==== * This adjustment will allow you to do the diffusion method very fast and still give the same brightness. * Skip steps [1] through [7] * Immerse a PFG-01 plate in a solution of 20% Sodium Thiosulfate (non hardening fixer) until it has become completely transparent. And rinse in DI water and dry. * Prepare a solution of 1 ml DI water + 0.18g AgNO3. * With a laser printer transparency spread a few drops of this solution over the surface of the fixed out plate and squeegie the plate very well. * Start from step 8 in the above procedure. * You have now upgraded your PFG-01 plate to a plate that competes well with the brightest plates in the world. I have done the original method, my adjusted method and the quicker method many times over and they give predictable results but have now switched to a completely different method (using double jet) that I don't want to write about just yet. ====INTERESTING EXPERIMENTS TO TRY==== *Gelatin at low concentration is much easier to coat than the 10% that is required for the above procedure. It would be interesting to try to make your fresh dry gelatin into a very fine powder in a kitchen slurpy mixer. Then load this fine powder in a very cold solution of AgNO3. The solution needs to be cold because otherwise the powder will become a sticky mass. Next run this mix through a coffee filter to drain off excess water+AgNO3. Then pour your LiBr+dye mixture over the powder that is still in the coffee filter (do catch what drips out of the filter because it can be used again). Next pour large amounts of DI water through the filter. If all liquids are rather cold during this procedure the gelatin will not clump up and it just might work. After this procedure you would have holographic gelatin that can dissolved when needed at concentrations of about 2% and coated by just pouring on a horizontal glass plate. I don't know if this procedure would work. But if it does work it would be very nice. I tried it once but made a mistake in the dark and made a mess of it. So I was not able to conclude if it is possible or not. *To coat a layer of 2% gelatin on glass to which some dichromate is added. Then make this layer really hard in an oven and use the shortcut method I wrote about above. The layer should be very smooth and hard enough to allow a good squeegee. I have not tried this, but if it works it will be a lot faster. Well, that's about all I know about the diffusion method. I very much enjoyed using it. Please understand that this is by no means the only way to do the diffusion method. If you want to have a go at it, try it this way first and then experiment with your own idea's. I am sure you will come up with idea's that will improve upon this method. ba140652647bf4333e5ef97742da5792bde95f07 0 274 2773 2542 2019-11-28T23:36:18Z Jsfisher 1 wikitext text/x-wiki Please add any links you have found useful. Try to alphabatize by Site title. '''[[Books]]''' can be found [[Books|here]]. ===Links to Holography Instruction=== *[http://home.comcast.net/~gakall/holopg/ Amateur Holography] Simple & Low Budget *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.nobel.se/physics/laureates/1971/gabor-lecture.pdf Dennis Gabor's Nobel Lecture, December 11, 1971] *[http://www.holographer.org The Holographer] *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] *[http://amasci.com/amateur/hand1.html Hand Drawn Holograms] *[http://www.holoworld.com/holoportraits/index.html Hand Made Hologram Portraits] An Amateur/Hobbyist Guide *[http://www.holostudios.com/holohelper/index.html Hologram Basic Principles] by Jason Sapan *[http://www.holokits.com/newsarticles.htm Integraf's Articles] *[http://www.focalimage.com/public/kaveh-PhD.pdf Kaveh's Thesis] *[http://www.buildcoolstuff.com/gallery/holograms.html Laser Pointer Holograms] *[http://www.repairfaq.org/sam/lasersam.htm Laser Sam's FAQ] The best source of laser related information on the net. *[http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html MIT Spring 2002 Holography course] *[http://www.holo.com/holo/book/book.html Practical Holography] by Christopher Outwater & Van Hamersveld *[http://www.holography.ru/techeng.htm Russion Holography 25 Holography Lessons] *[http://www.dragonseye.com/blog/categories/2-Tutorials Holography Tutorials] by Michael Harrison *[http://www.physics.ohio-state.edu/~kagan/holography/index.html Holography course at Ohio State] *[http://teched.vt.edu/gcc/CurriculumMaterials/HoloProject/HTML/index.html Virtual Holography course at Virginia Tech] *[http://www.ph.ed.ac.uk/~wjh/teaching/mo/holography.html University of Edinburgh] *[http://www.3dimagery.com Nuts to bolts online descriptions for hobbyist] *[http://geola.lt/download/synfography_virtual_scene_setup.pdf Synfography basics - virtual scene setup for Geola's colour holographic printing] ===Links to Holography Supplies and Tools=== ====Turnkey Equipment==== *[http://www.myholostudio.com/ Analogue holography] {Complete holography studios} *[http://geola.lt/show.php?lang=eng&cont=holo_index&lside=holo_index_left Digital holographic printing - Synfography] {Complete digital solutions} ====Electronics==== *[http://www.digikey.com DigiKey] {Electronics} *[http://www.goldmine-elec.com Gold Mine Electronics] *[http://www.allelectronics.com/ All Electronics] {Electronics} *[http://www.alltronics.com Alltronics] {Electronics} *[http://www.oatleyelectronics.com/ Oatley Electronics] {Electronics} *[http://www.mouser.com/Mouser Mouser] {Electronics} ====Film and Chemistry==== *[http://www.litiholo.com LitiHolo] Film, holography kits, color holography kits, educational material. (Special discount available to members of [https://holographyforum.org Holography Forum].) *[http://www.integraf.com Integraf] Film, Kits and Books *[http://www.laserreflections.com Laser Reflections] Film *[http://www.slavich.com Slavich] Film, Plates and Chemistry *[http://www.geola.lt/eshop/index.htm Geola] Certified Slavich film and plates made for Geola distribution network, Chemistry *[http://www.ilfordphoto.com/holofx/holofx.asp Ilford] Harman HoloFX fine-grain red and green sensitive plates *[http://www.adorama.com Adorama] Supplier of Harman HoloFX plates *[http://www.forthdimension.net Forth Dimension] Film and Supplies *[http://www.photoformulary.com Photographer's Formulary] Chemistry *[http://www.sigmaaldrich.com/ Sigma Aldrich] Chemicals *[http://perso.wanadoo.fr/holographie/GB/index.html Ultimate Film] Film *[http://www.abra-electronics.com Abra Electronics] Isopropyl Alcohol *[http://www.colourholographic.com Colour Holographics] BB Plates - Red, Green, Blue, Pan *[http://www.filmotec.de/Produkte/produkte.html Filmotec] ORWO - Red, Green, Pan in works *[http://www.fujihunt.com/fuji/fhweb2004.nsf/pagesbykey/Holo%20products?OpenDocument Fuji] Pan said to be discontinued ====Kits==== *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.geola.lt/show.php?lang=eng&cont=phot_en_kit&lside=phot_index_left Geola] {Holography supply refill kit} ====Lasers, Parts and Supplies==== *[http://www.optima-optics.com Optima] {Laser Diode Parts} *[http://www.nvginc.com NVG Inc.] {Laser Diode Parts} *[http://www.mi-lasers.com/index1.html Meredith Instruments] {Used Gas Lasers} *[http://www.roithner-laser.com/ Roithner] {Lasers and diodes} *[http://www.cnilaser.com/ CNI Laser] {DPSS Lasers}] *[http://www.lasersurplus.com/ Laser Surplus Sales] {Used Lasers} *[http://www.innolas.co.uk/ Innovative Laser Technology] {Lasers and parts} *[http://www.geola.com/ Geola] {High energy pulsed lasers, Holographic studios} ====Optics and Table Supplies==== *[http://www.thorlabs.com Thor Labs] {Optics} *[http://www.edmundoptics.com/us/onlinecatalog/browse.cfm Edmund Optics] {Optics} *[http://www.imagesco.com ImagesCo] {Supplies and inexpensive optics} *[http://www.surplusshed.com Surplus Shed] {Surplus Optics} *[http://www.murni.com/kit_0.htm Coulter Telescopes] {Inexpensive Collimating Mirrors} *[http://www.abrisa.com/index.asp Abrisa] {Glass Products, Dichroic Mirrors} *[http://www.lenoxlaser.com/ Lenox Laser] {Piinholes} *[http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=5646 Harbor Freight] {Magnetic Bases} *[http://www.use-enco.com/CGI/INSRIT?PMAKA=625-0300&PMPXNO=946102&PARTPG=INLMK3 ENCO] {Magnetic Bases} *[http://www.geola.com/ Geola] {Optics for pulsed holography} ====Robotics==== *[http://www.solarbotics.com SolarBotics] {Robot Technology} ====Surplus and Other Stuff==== *[http://www.sciplus.com American Science Surplus] {Surplus Parts and Cool Stuff} *[http://www.spsenergy.com/index.htm SPS Energy] {Solar Cells as Light Meter Probes} *[http://www.fgsi.com/oracal.htm Oracal] {instead of black paint for reflection holos #651} ====Tooling and Machining==== *[http://www.reidtool.com Reid Tool] {Tooling supplies} *[http://www.mscindustrial.com MSC Industrial] {Raw Metal and Machining Supplies} *[http://www.mcmaster.com McMaster Carr] {Raw Metal and Machining Supplies} ====Tools==== *[http://www.use-enco.com Enco] {Tools} ====Technical==== *[http://www.moshier.net/rtd-readme.html Thermistor calibration] ===Links to Amateur/Individual Holographers=== *[http://www.techsoft.no/holography/ronny_anderassen.htm Ronnie Anderassen] *[http://www.anait.com/ Anait] *[http://members.shaw.ca/holopix/My_holograms.html TomB] *[http://www.holography.demon.co.uk/ Margaret Benyon] *[http://rudieberkhout.home.mindspring.com/ Rudie Berkhout] *[http://cabd0.tripod.com/holograms/ Jeff Blyth] *[http://universal-hologram.com/index.htm Greg Cherry] *[http://web.mit.edu/museum/lightforest/lightforest.html Betsy Connors] *[http://www.holoworld.com/ Frank Defreitas] *[http://www.jfairstein.com/holoindex.html Jon Fairstein] *[http://www.hologramm.ch.vu/ Floh] *[http://webhome.idirect.com/~hgdesign Howard Gerry] *[http://www.ghisays.net Andres Ghisays] *[http://universal-hologram.com/nini%20gorglione.htm Nancy Gorglione] *[http://www.dragonseye.com/blog Michael Harrison] *[http://www.techsoft.no/holography Vidar Hegdal] *[http://www.pearljohn.co.uk/ Pearl John] [http://pearljohn.blogspot.com/ her Blog] *[http://www.bobdbob.com/~protius Tommy Johnson] *[http://www.designerinlight.com Colin Kaminski] *[http://www.holocenter.or.kr/ Juyong Lee] *[http://www.lucente.biz/index.html Mark Lucente] *[http://www.indimensionn.com/page3.html Bill McGarvin] *[http://www.holography.nl/ Kris Meerlo] *[http://www.rotorwave.com/holography.htm Ron Michael] *[http://www.3dimagery.com Steve Michael] *[http://holographics.com.au/ Martina Mrongovius] *[http://www.lasart.com/ August Muth] *[http://www.hololab.com/ Ikuo Nakamura] *[http://www.anamarianicholson.com/ Ana Maria Nicholson] *[http://www.holograms3d.com/ John Pecora] *[http://www.apepper.com/ Andrew Pepper] *[http://www.alchemists.com/visual_alchemy/holography.html Al Razutis] *[http://www.vilamedia.com/gallery.html Doris Vila] *[http://wengam.com/ Wenyon & Gamble] *[http://perso.wanadoo.fr/redlum.xohp/argonlaser.html W's Laser Projects Page] *[http://www.martymouse.net/happyfeet/ Danny Bruza (Danny Bee)] ===Links to Holograms For Sale=== *[http://www.holography.ru/maineng.htm Beautiful Russian Holograms] *[http://www.holograms.bc.ca Royal Holographic Art Gallery] *[http://holographiccenter.com/ Holographic Center] *[http://www.triple-take.com Triple-Take] *[http://www.hologramstore.biz Dragon's Eye Creations] *[http://www.holoshop.nl HoloShop.nl] *[http://www.holoshop.com Holograms & Lasers Intl] *[http://www.geola.lt/show.php?lang=eng&cont=holoindex&lside=holo_index_left Geola - Digital holographic prints - Synfograms - Colour and movement in one] *[http://universal-hologram.com/ Hologram Art] *[http://www.rabbitholes.com/art-gallery/ Holographic Art Prints from Computer 3D and Animation from Leading 3D Artists] *[http://www.rabbitholes.com/order-samples/ Samples kits of Rabbitholes Holograms] ===Links to Professional Holographers=== *[http://www.3dimagery.com Three Dimensional Imagery] Hologram Production Lab *[http://universal-hologram.com/index.htm Cherry Optical] Hologram Production Lab *[http://www.forthdimension.net Forth Dimension] Hologram Production Lab *[http://www.holonorth.com/main.html Holographics North] Hologram Production Lab *[http://www.holographsonmain.com Holographs on Main] Portrait Studio *[http://www.laserreflections.com Laser Reflections] Pulsed Holography Lab *[http://www.zebraimaging.com Zebra Imaging] Hologram Production Lab *[http://www.geola.lt Geola] Synfograms (Geola's digital holograms) - life scene colour imaging with animation *[http://www.rabbitholes.com RabbitHoles Media] Full color digital hologram production ===Organizations=== *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.holography.co.uk/index.shtml Royal Photographic Society] *[http://www.spie.org The International Society for Optical Engineering] *[http://www.IHMA.org International Hologram Manufacturers Association] *[http://www.holographynews.info Holography News - Industry information] 80e54e4e8d1eece2b122de3ee17847afaababf4a 2774 2773 2019-11-28T23:38:21Z Jsfisher 1 wikitext text/x-wiki Please add any links you have found useful. Try to alphabatize by Site title. '''[[Books]]''' can be found [[Books|here]]. ===Links to Holography Instruction=== *[http://home.comcast.net/~gakall/holopg/ Amateur Holography] Simple & Low Budget *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.nobel.se/physics/laureates/1971/gabor-lecture.pdf Dennis Gabor's Nobel Lecture, December 11, 1971] *[http://www.holographer.org The Holographer] *[http://holography.co.uk/hcon1jb.pdf Jeff Blyth's recipe for making your own silver plates] *[http://amasci.com/amateur/hand1.html Hand Drawn Holograms] *[http://www.holoworld.com/holoportraits/index.html Hand Made Hologram Portraits] An Amateur/Hobbyist Guide *[http://www.holostudios.com/holohelper/index.html Hologram Basic Principles] by Jason Sapan *[http://www.holokits.com/newsarticles.htm Integraf's Articles] *[http://www.focalimage.com/public/kaveh-PhD.pdf Kaveh's Thesis] *[http://www.buildcoolstuff.com/gallery/holograms.html Laser Pointer Holograms] *[http://www.repairfaq.org/sam/lasersam.htm Laser Sam's FAQ] The best source of laser related information on the net. *[http://courses.media.mit.edu/2002spring/mas450/reading/other_handouts/spatial_freq/index.html MIT Spring 2002 Holography course] *[http://www.holo.com/holo/book/book.html Practical Holography] by Christopher Outwater & Van Hamersveld *[http://www.holography.ru/techeng.htm Russion Holography 25 Holography Lessons] *[http://www.dragonseye.com/blog/categories/2-Tutorials Holography Tutorials] by Michael Harrison *[http://www.physics.ohio-state.edu/~kagan/holography/index.html Holography course at Ohio State] *[http://teched.vt.edu/gcc/CurriculumMaterials/HoloProject/HTML/index.html Virtual Holography course at Virginia Tech] *[http://www.ph.ed.ac.uk/~wjh/teaching/mo/holography.html University of Edinburgh] *[http://www.3dimagery.com Nuts to bolts online descriptions for hobbyist] *[http://geola.lt/download/synfography_virtual_scene_setup.pdf Synfography basics - virtual scene setup for Geola's colour holographic printing] ===Links to Holography Supplies and Tools=== ====Turnkey Equipment==== *[http://www.myholostudio.com/ Analogue holography] {Complete holography studios} *[http://geola.lt/show.php?lang=eng&cont=holo_index&lside=holo_index_left Digital holographic printing - Synfography] {Complete digital solutions} ====Electronics==== *[http://www.digikey.com DigiKey] {Electronics} *[http://www.goldmine-elec.com Gold Mine Electronics] *[http://www.allelectronics.com/ All Electronics] {Electronics} *[http://www.alltronics.com Alltronics] {Electronics} *[http://www.oatleyelectronics.com/ Oatley Electronics] {Electronics} *[http://www.mouser.com/Mouser Mouser] {Electronics} ====Film and Chemistry==== *[http://www.litiholo.com LitiHolo] Film, holography kits, color holography kits, educational material. (Special discount available to members of [https://holographyforum.org Holography Forum].) *[http://www.integraf.com Integraf] Film, Kits and Books *[http://www.laserreflections.com Laser Reflections] Film *[http://www.slavich.com Slavich] Film, Plates and Chemistry *[http://www.geola.lt/eshop/index.htm Geola] Certified Slavich film and plates made for Geola distribution network, Chemistry *[http://www.ilfordphoto.com/holofx/holofx.asp Ilford] Harman HoloFX fine-grain red and green sensitive plates *[http://www.adorama.com Adorama] Supplier of Harman HoloFX plates *[http://www.forthdimension.net Forth Dimension] Film and Supplies *[http://www.photoformulary.com Photographer's Formulary] Chemistry *[http://www.sigmaaldrich.com/ Sigma Aldrich] Chemicals *[http://perso.wanadoo.fr/holographie/GB/index.html Ultimate Film] Film *[http://www.abra-electronics.com Abra Electronics] Isopropyl Alcohol *[http://www.colourholographic.com Colour Holographics] BB Plates - Red, Green, Blue, Pan *[http://www.filmotec.de/Produkte/produkte.html Filmotec] ORWO - Red, Green, Pan in works *[http://www.fujihunt.com/fuji/fhweb2004.nsf/pagesbykey/Holo%20products?OpenDocument Fuji] Pan said to be discontinued ====Kits==== *[http://www.litiholo.com LitiHolo] Film, holography kits, color holography kits, educational material. (Special discount available to members of [https://holographyforum.org Holography Forum].) *[http://www.integraf.com Integraf] {Film, Kits and Books} *[http://www.geola.lt/show.php?lang=eng&cont=phot_en_kit&lside=phot_index_left Geola] {Holography supply refill kit} ====Lasers, Parts and Supplies==== *[http://www.optima-optics.com Optima] {Laser Diode Parts} *[http://www.nvginc.com NVG Inc.] {Laser Diode Parts} *[http://www.mi-lasers.com/index1.html Meredith Instruments] {Used Gas Lasers} *[http://www.roithner-laser.com/ Roithner] {Lasers and diodes} *[http://www.cnilaser.com/ CNI Laser] {DPSS Lasers}] *[http://www.lasersurplus.com/ Laser Surplus Sales] {Used Lasers} *[http://www.innolas.co.uk/ Innovative Laser Technology] {Lasers and parts} *[http://www.geola.com/ Geola] {High energy pulsed lasers, Holographic studios} ====Optics and Table Supplies==== *[http://www.thorlabs.com Thor Labs] {Optics} *[http://www.edmundoptics.com/us/onlinecatalog/browse.cfm Edmund Optics] {Optics} *[http://www.imagesco.com ImagesCo] {Supplies and inexpensive optics} *[http://www.surplusshed.com Surplus Shed] {Surplus Optics} *[http://www.murni.com/kit_0.htm Coulter Telescopes] {Inexpensive Collimating Mirrors} *[http://www.abrisa.com/index.asp Abrisa] {Glass Products, Dichroic Mirrors} *[http://www.lenoxlaser.com/ Lenox Laser] {Piinholes} *[http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=5646 Harbor Freight] {Magnetic Bases} *[http://www.use-enco.com/CGI/INSRIT?PMAKA=625-0300&PMPXNO=946102&PARTPG=INLMK3 ENCO] {Magnetic Bases} *[http://www.geola.com/ Geola] {Optics for pulsed holography} ====Robotics==== *[http://www.solarbotics.com SolarBotics] {Robot Technology} ====Surplus and Other Stuff==== *[http://www.sciplus.com American Science Surplus] {Surplus Parts and Cool Stuff} *[http://www.spsenergy.com/index.htm SPS Energy] {Solar Cells as Light Meter Probes} *[http://www.fgsi.com/oracal.htm Oracal] {instead of black paint for reflection holos #651} ====Tooling and Machining==== *[http://www.reidtool.com Reid Tool] {Tooling supplies} *[http://www.mscindustrial.com MSC Industrial] {Raw Metal and Machining Supplies} *[http://www.mcmaster.com McMaster Carr] {Raw Metal and Machining Supplies} ====Tools==== *[http://www.use-enco.com Enco] {Tools} ====Technical==== *[http://www.moshier.net/rtd-readme.html Thermistor calibration] ===Links to Amateur/Individual Holographers=== *[http://www.techsoft.no/holography/ronny_anderassen.htm Ronnie Anderassen] *[http://www.anait.com/ Anait] *[http://members.shaw.ca/holopix/My_holograms.html TomB] *[http://www.holography.demon.co.uk/ Margaret Benyon] *[http://rudieberkhout.home.mindspring.com/ Rudie Berkhout] *[http://cabd0.tripod.com/holograms/ Jeff Blyth] *[http://universal-hologram.com/index.htm Greg Cherry] *[http://web.mit.edu/museum/lightforest/lightforest.html Betsy Connors] *[http://www.holoworld.com/ Frank Defreitas] *[http://www.jfairstein.com/holoindex.html Jon Fairstein] *[http://www.hologramm.ch.vu/ Floh] *[http://webhome.idirect.com/~hgdesign Howard Gerry] *[http://www.ghisays.net Andres Ghisays] *[http://universal-hologram.com/nini%20gorglione.htm Nancy Gorglione] *[http://www.dragonseye.com/blog Michael Harrison] *[http://www.techsoft.no/holography Vidar Hegdal] *[http://www.pearljohn.co.uk/ Pearl John] [http://pearljohn.blogspot.com/ her Blog] *[http://www.bobdbob.com/~protius Tommy Johnson] *[http://www.designerinlight.com Colin Kaminski] *[http://www.holocenter.or.kr/ Juyong Lee] *[http://www.lucente.biz/index.html Mark Lucente] *[http://www.indimensionn.com/page3.html Bill McGarvin] *[http://www.holography.nl/ Kris Meerlo] *[http://www.rotorwave.com/holography.htm Ron Michael] *[http://www.3dimagery.com Steve Michael] *[http://holographics.com.au/ Martina Mrongovius] *[http://www.lasart.com/ August Muth] *[http://www.hololab.com/ Ikuo Nakamura] *[http://www.anamarianicholson.com/ Ana Maria Nicholson] *[http://www.holograms3d.com/ John Pecora] *[http://www.apepper.com/ Andrew Pepper] *[http://www.alchemists.com/visual_alchemy/holography.html Al Razutis] *[http://www.vilamedia.com/gallery.html Doris Vila] *[http://wengam.com/ Wenyon & Gamble] *[http://perso.wanadoo.fr/redlum.xohp/argonlaser.html W's Laser Projects Page] *[http://www.martymouse.net/happyfeet/ Danny Bruza (Danny Bee)] ===Links to Holograms For Sale=== *[http://www.holography.ru/maineng.htm Beautiful Russian Holograms] *[http://www.holograms.bc.ca Royal Holographic Art Gallery] *[http://holographiccenter.com/ Holographic Center] *[http://www.triple-take.com Triple-Take] *[http://www.hologramstore.biz Dragon's Eye Creations] *[http://www.holoshop.nl HoloShop.nl] *[http://www.holoshop.com Holograms & Lasers Intl] *[http://www.geola.lt/show.php?lang=eng&cont=holoindex&lside=holo_index_left Geola - Digital holographic prints - Synfograms - Colour and movement in one] *[http://universal-hologram.com/ Hologram Art] *[http://www.rabbitholes.com/art-gallery/ Holographic Art Prints from Computer 3D and Animation from Leading 3D Artists] *[http://www.rabbitholes.com/order-samples/ Samples kits of Rabbitholes Holograms] ===Links to Professional Holographers=== *[http://www.3dimagery.com Three Dimensional Imagery] Hologram Production Lab *[http://universal-hologram.com/index.htm Cherry Optical] Hologram Production Lab *[http://www.forthdimension.net Forth Dimension] Hologram Production Lab *[http://www.holonorth.com/main.html Holographics North] Hologram Production Lab *[http://www.holographsonmain.com Holographs on Main] Portrait Studio *[http://www.laserreflections.com Laser Reflections] Pulsed Holography Lab *[http://www.zebraimaging.com Zebra Imaging] Hologram Production Lab *[http://www.geola.lt Geola] Synfograms (Geola's digital holograms) - life scene colour imaging with animation *[http://www.rabbitholes.com RabbitHoles Media] Full color digital hologram production ===Organizations=== *[http://www.holocenter.org/ Center for the Holographic Arts] *[http://www.holography.co.uk/index.shtml Royal Photographic Society] *[http://www.spie.org The International Society for Optical Engineering] *[http://www.IHMA.org International Hologram Manufacturers Association] *[http://www.holographynews.info Holography News - Industry information] 0b698a9f5148be803153e5d27075c89f85d1c718 0 1 2775 2772 2020-04-26T03:20:09Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [https://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=https://holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} <!--{{note|'''Temporary Outage Scheduled:''' Beginning Monday, May 11, 2020, the Holography Forum and the Wiki may be unavailable from approximately 11:30am EDT (3:30pm UTC) for up to 1 hour Monday through Wednesday, and then from 8:00am to 1:00pm (noon to 5:00pm UTC) on Thursday, May 14, 2020. This is due to some electrical system maintenance. (While my hosting provider for the forum and wiki has been very generous over the years providing Internet connectivity at no cost, the generosity never included backup power.) I apologize for the inconvenience this outage may cause.|gotcha}}--> '''[https://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 71f30079b447c72a3805765a83c90b79e6b2bea5 2776 2775 2020-04-26T03:20:34Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [https://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=https://holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} {{note|'''Temporary Outage Scheduled:''' Beginning Monday, May 11, 2020, the Holography Forum and the Wiki may be unavailable from approximately 11:30am EDT (3:30pm UTC) for up to 1 hour Monday through Wednesday, and then from 8:00am to 1:00pm (noon to 5:00pm UTC) on Thursday, May 14, 2020. This is due to some electrical system maintenance. (While my hosting provider for the forum and wiki has been very generous over the years providing Internet connectivity at no cost, the generosity never included backup power.) I apologize for the inconvenience this outage may cause.|gotcha}} '''[https://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] f454e9f52f275d848d02b2825b9a45281acf3af5 2777 2776 2020-05-29T00:14:43Z Jsfisher 1 wikitext text/x-wiki {{#seo: |description=Master reference for all things holographic}} '''<big>Welcome to the [https://holographyforum.org/forum Holography Forum's] Holography Wiki - A Holography FAQ and Database for anyone who makes holograms.</big>''' {| class="wikitable" style="color: white; background-color:#4499ff;" width="500em" |- | [[Image:HoloforumLogo.gif|left|link=https://holographyforum.org/forum]] <br /> '''<big>Holographyforum.org / holowiki.org</big>'''<br />A place to discuss holography |} <!-- {{note|'''Temporary Outage Scheduled:''' Beginning Monday, May 11, 2020, the Holography Forum and the Wiki may be unavailable from approximately 11:30am EDT (3:30pm UTC) for up to 1 hour Monday through Wednesday, and then from 8:00am to 1:00pm (noon to 5:00pm UTC) on Thursday, May 14, 2020. This is due to some electrical system maintenance. (While my hosting provider for the forum and wiki has been very generous over the years providing Internet connectivity at no cost, the generosity never included backup power.) I apologize for the inconvenience this outage may cause.|gotcha}} --> '''[https://holowiki.org/forum Holography Forum]''' is the online discussion vehicle for an eclectic group of holography enthusiasts, experts, amateurs, and professionals. The forum itself is a wealth of information, and new topics for discussion are always welcome. Newcomers are warmly welcomed. You may browse the various discussion threads as a guest, and it costs nothing to sign up as a full forum member. Your host for this Holowiki site is [[User:jsfisher| John Fisher]], chief volunteer with the honor of being site administrator. [[Image:JohnFP AngelMusic.jpg|right|400px|]] == New Stuff and Recent Additions == * Presentation slides from the '''[[ISDH 2015 | Tenth International Symposium on Display Holography]]''', provided by Petr Lobaz. * '''Holography Forum''' has moved back to its original home at http://holographyforum.org/forum. * Experiment with '''[[Experimenter's Corner#Albumen Emulsion Plates | albumen plates]]''' by Filipe Alves. * '''[[Cold Water Processing]]''' article by Ed Wesly. * Compilation of '''[[Ewesly_/_Holographic_Formulae | chemistry for holographic developers and bleaches]]''', courtesy of Ed Wesly. * '''[[DCG Color Tuning]]''' guide derived form the Holography Forum archives. == Basic Information == * '''[[Beginner's Corner]].''' Basic information for getting a start in holography. * '''[[Dichromated Gelatin]].''' Basic information about branching off into the realm of DCG holography. * '''[[Experimenter's Corner]].''' Odd things to try, or what others have tried. * '''[[Hints and Kinks]].''' Tips and techniques shared by others. * '''[[Equipment]].''' Things used in making holograms. ** '''[[Homemade Equipment]].''' Some equipment is easily made at home. * '''[[Gallery]].''' Great examples of success, failure, and experiments. == A Little History == * '''[[History of Holography|History of Holography]].''' The timeline of the people and technology. * '''[[History of Dichromates | History of Dichromate Holography]].''' A timeline of the people and technology in the advancement of dichromated gelatin holography. * '''[[Biographies of Holographers|Biographies of Holographers]].''' The people who have made it all possible. == Advanced Information == * '''[[Holography Safety|Holography Safety]].''' Chemical and laser safety. A must read! * '''[[Abbreviations|Abbreviations]].''' Commonly used abbreviations by holographers. * '''[[Holography Glossary|Holography Glossary]].''' Holography technical terms defined. * '''[[Holography Technology|Holography Technology]].''' The hardware and setups for making holograms. * '''[[Hologram Recording Materials|Hologram Recording Materials]].''' How to get, make and use them and chemistry. * '''[[Holography Theory|Holography Theory]].''' The Mathematics and Science of Holography. == Other Resources == * '''[[Holography Links|Holography Links]].''' Other resources for holographers on the web. * '''[[Reading Room]].''' Miscellaneous interesting documents that need to be cataloged. * '''[[:Category:Rallison|Category:Rallison]].''' Information recovered from Ralcon site (Richard Rallison). * [[Archives|Archives]] 85c0ce80ad00a91252a84c5b0c11100945b988a4